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Move modules/gzip to gitea.com/macaron/gzip (#9058)

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* Move modules/gzip to gitea.com/macaron/gzip

* Fix vendor
This commit is contained in:
Lunny Xiao 2019-11-18 13:18:33 +08:00 • committed by GitHub
parent ba4e8f221b
commit 9ff6312627
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GPG key ID: 4AEE18F83AFDEB23
54 changed files with 2972 additions and 5163 deletions
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1
vendor/github.com/klauspost/compress/LICENSE generated vendored
View file

@ -1,4 +1,5 @@
Copyright (c) 2012 The Go Authors. All rights reserved.
Copyright (c) 2019 Klaus Post. All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are

32
vendor/github.com/klauspost/compress/flate/copy.go generated vendored
View file

@ -1,32 +0,0 @@
// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package flate
// forwardCopy is like the built-in copy function except that it always goes
// forward from the start, even if the dst and src overlap.
// It is equivalent to:
// for i := 0; i < n; i++ {
// mem[dst+i] = mem[src+i]
// }
func forwardCopy(mem []byte, dst, src, n int) {
if dst <= src {
copy(mem[dst:dst+n], mem[src:src+n])
return
}
for {
if dst >= src+n {
copy(mem[dst:dst+n], mem[src:src+n])
return
}
// There is some forward overlap. The destination
// will be filled with a repeated pattern of mem[src:src+k].
// We copy one instance of the pattern here, then repeat.
// Each time around this loop k will double.
k := dst - src
copy(mem[dst:dst+k], mem[src:src+k])
n -= k
dst += k
}
}

41
vendor/github.com/klauspost/compress/flate/crc32_amd64.go generated vendored
View file

@ -1,41 +0,0 @@
//+build !noasm
//+build !appengine
// Copyright 2015, Klaus Post, see LICENSE for details.
package flate
import (
"github.com/klauspost/cpuid"
)
// crc32sse returns a hash for the first 4 bytes of the slice
// len(a) must be >= 4.
//go:noescape
func crc32sse(a []byte) uint32
// crc32sseAll calculates hashes for each 4-byte set in a.
// dst must be east len(a) - 4 in size.
// The size is not checked by the assembly.
//go:noescape
func crc32sseAll(a []byte, dst []uint32)
// matchLenSSE4 returns the number of matching bytes in a and b
// up to length 'max'. Both slices must be at least 'max'
// bytes in size.
//
// TODO: drop the "SSE4" name, since it doesn't use any SSE instructions.
//
//go:noescape
func matchLenSSE4(a, b []byte, max int) int
// histogram accumulates a histogram of b in h.
// h must be at least 256 entries in length,
// and must be cleared before calling this function.
//go:noescape
func histogram(b []byte, h []int32)
// Detect SSE 4.2 feature.
func init() {
useSSE42 = cpuid.CPU.SSE42()
}

213
vendor/github.com/klauspost/compress/flate/crc32_amd64.s generated vendored
View file

@ -1,213 +0,0 @@
//+build !noasm
//+build !appengine
// Copyright 2015, Klaus Post, see LICENSE for details.
// func crc32sse(a []byte) uint32
TEXT ·crc32sse(SB), 4, $0
MOVQ a+0(FP), R10
XORQ BX, BX
// CRC32 dword (R10), EBX
BYTE $0xF2; BYTE $0x41; BYTE $0x0f
BYTE $0x38; BYTE $0xf1; BYTE $0x1a
MOVL BX, ret+24(FP)
RET
// func crc32sseAll(a []byte, dst []uint32)
TEXT ·crc32sseAll(SB), 4, $0
MOVQ a+0(FP), R8 // R8: src
MOVQ a_len+8(FP), R10 // input length
MOVQ dst+24(FP), R9 // R9: dst
SUBQ $4, R10
JS end
JZ one_crc
MOVQ R10, R13
SHRQ $2, R10 // len/4
ANDQ $3, R13 // len&3
XORQ BX, BX
ADDQ $1, R13
TESTQ R10, R10
JZ rem_loop
crc_loop:
MOVQ (R8), R11
XORQ BX, BX
XORQ DX, DX
XORQ DI, DI
MOVQ R11, R12
SHRQ $8, R11
MOVQ R12, AX
MOVQ R11, CX
SHRQ $16, R12
SHRQ $16, R11
MOVQ R12, SI
// CRC32 EAX, EBX
BYTE $0xF2; BYTE $0x0f
BYTE $0x38; BYTE $0xf1; BYTE $0xd8
// CRC32 ECX, EDX
BYTE $0xF2; BYTE $0x0f
BYTE $0x38; BYTE $0xf1; BYTE $0xd1
// CRC32 ESI, EDI
BYTE $0xF2; BYTE $0x0f
BYTE $0x38; BYTE $0xf1; BYTE $0xfe
MOVL BX, (R9)
MOVL DX, 4(R9)
MOVL DI, 8(R9)
XORQ BX, BX
MOVL R11, AX
// CRC32 EAX, EBX
BYTE $0xF2; BYTE $0x0f
BYTE $0x38; BYTE $0xf1; BYTE $0xd8
MOVL BX, 12(R9)
ADDQ $16, R9
ADDQ $4, R8
XORQ BX, BX
SUBQ $1, R10
JNZ crc_loop
rem_loop:
MOVL (R8), AX
// CRC32 EAX, EBX
BYTE $0xF2; BYTE $0x0f
BYTE $0x38; BYTE $0xf1; BYTE $0xd8
MOVL BX, (R9)
ADDQ $4, R9
ADDQ $1, R8
XORQ BX, BX
SUBQ $1, R13
JNZ rem_loop
end:
RET
one_crc:
MOVQ $1, R13
XORQ BX, BX
JMP rem_loop
// func matchLenSSE4(a, b []byte, max int) int
TEXT ·matchLenSSE4(SB), 4, $0
MOVQ a_base+0(FP), SI
MOVQ b_base+24(FP), DI
MOVQ DI, DX
MOVQ max+48(FP), CX
cmp8:
// As long as we are 8 or more bytes before the end of max, we can load and
// compare 8 bytes at a time. If those 8 bytes are equal, repeat.
CMPQ CX, $8
JLT cmp1
MOVQ (SI), AX
MOVQ (DI), BX
CMPQ AX, BX
JNE bsf
ADDQ $8, SI
ADDQ $8, DI
SUBQ $8, CX
JMP cmp8
bsf:
// If those 8 bytes were not equal, XOR the two 8 byte values, and return
// the index of the first byte that differs. The BSF instruction finds the
// least significant 1 bit, the amd64 architecture is little-endian, and
// the shift by 3 converts a bit index to a byte index.
XORQ AX, BX
BSFQ BX, BX
SHRQ $3, BX
ADDQ BX, DI
// Subtract off &b[0] to convert from &b[ret] to ret, and return.
SUBQ DX, DI
MOVQ DI, ret+56(FP)
RET
cmp1:
// In the slices' tail, compare 1 byte at a time.
CMPQ CX, $0
JEQ matchLenEnd
MOVB (SI), AX
MOVB (DI), BX
CMPB AX, BX
JNE matchLenEnd
ADDQ $1, SI
ADDQ $1, DI
SUBQ $1, CX
JMP cmp1
matchLenEnd:
// Subtract off &b[0] to convert from &b[ret] to ret, and return.
SUBQ DX, DI
MOVQ DI, ret+56(FP)
RET
// func histogram(b []byte, h []int32)
TEXT ·histogram(SB), 4, $0
MOVQ b+0(FP), SI // SI: &b
MOVQ b_len+8(FP), R9 // R9: len(b)
MOVQ h+24(FP), DI // DI: Histogram
MOVQ R9, R8
SHRQ $3, R8
JZ hist1
XORQ R11, R11
loop_hist8:
MOVQ (SI), R10
MOVB R10, R11
INCL (DI)(R11*4)
SHRQ $8, R10
MOVB R10, R11
INCL (DI)(R11*4)
SHRQ $8, R10
MOVB R10, R11
INCL (DI)(R11*4)
SHRQ $8, R10
MOVB R10, R11
INCL (DI)(R11*4)
SHRQ $8, R10
MOVB R10, R11
INCL (DI)(R11*4)
SHRQ $8, R10
MOVB R10, R11
INCL (DI)(R11*4)
SHRQ $8, R10
MOVB R10, R11
INCL (DI)(R11*4)
SHRQ $8, R10
INCL (DI)(R10*4)
ADDQ $8, SI
DECQ R8
JNZ loop_hist8
hist1:
ANDQ $7, R9
JZ end_hist
XORQ R10, R10
loop_hist1:
MOVB (SI), R10
INCL (DI)(R10*4)
INCQ SI
DECQ R9
JNZ loop_hist1
end_hist:
RET

35
vendor/github.com/klauspost/compress/flate/crc32_noasm.go generated vendored
View file

@ -1,35 +0,0 @@
//+build !amd64 noasm appengine
// Copyright 2015, Klaus Post, see LICENSE for details.
package flate
func init() {
useSSE42 = false
}
// crc32sse should never be called.
func crc32sse(a []byte) uint32 {
panic("no assembler")
}
// crc32sseAll should never be called.
func crc32sseAll(a []byte, dst []uint32) {
panic("no assembler")
}
// matchLenSSE4 should never be called.
func matchLenSSE4(a, b []byte, max int) int {
panic("no assembler")
return 0
}
// histogram accumulates a histogram of b in h.
//
// len(h) must be >= 256, and h's elements must be all zeroes.
func histogram(b []byte, h []int32) {
h = h[:256]
for _, t := range b {
h[t]++
}
}

893
vendor/github.com/klauspost/compress/flate/deflate.go generated vendored
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File diff suppressed because it is too large Load diff

257
vendor/github.com/klauspost/compress/flate/fast_encoder.go generated vendored Normal file
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@ -0,0 +1,257 @@
// Copyright 2011 The Snappy-Go Authors. All rights reserved.
// Modified for deflate by Klaus Post (c) 2015.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package flate
import (
"fmt"
"math/bits"
)
type fastEnc interface {
Encode(dst *tokens, src []byte)
Reset()
}
func newFastEnc(level int) fastEnc {
switch level {
case 1:
return &fastEncL1{fastGen: fastGen{cur: maxStoreBlockSize}}
case 2:
return &fastEncL2{fastGen: fastGen{cur: maxStoreBlockSize}}
case 3:
return &fastEncL3{fastGen: fastGen{cur: maxStoreBlockSize}}
case 4:
return &fastEncL4{fastGen: fastGen{cur: maxStoreBlockSize}}
case 5:
return &fastEncL5{fastGen: fastGen{cur: maxStoreBlockSize}}
case 6:
return &fastEncL6{fastGen: fastGen{cur: maxStoreBlockSize}}
default:
panic("invalid level specified")
}
}
const (
tableBits = 16 // Bits used in the table
tableSize = 1 << tableBits // Size of the table
tableShift = 32 - tableBits // Right-shift to get the tableBits most significant bits of a uint32.
baseMatchOffset = 1 // The smallest match offset
baseMatchLength = 3 // The smallest match length per the RFC section 3.2.5
maxMatchOffset = 1 << 15 // The largest match offset
bTableBits = 18 // Bits used in the big tables
bTableSize = 1 << bTableBits // Size of the table
allocHistory = maxMatchOffset * 10 // Size to preallocate for history.
bufferReset = (1 << 31) - allocHistory - maxStoreBlockSize // Reset the buffer offset when reaching this.
)
const (
prime3bytes = 506832829
prime4bytes = 2654435761
prime5bytes = 889523592379
prime6bytes = 227718039650203
prime7bytes = 58295818150454627
prime8bytes = 0xcf1bbcdcb7a56463
)
func load32(b []byte, i int) uint32 {
// Help the compiler eliminate bounds checks on the read so it can be done in a single read.
b = b[i:]
b = b[:4]
return uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24
}
func load64(b []byte, i int) uint64 {
// Help the compiler eliminate bounds checks on the read so it can be done in a single read.
b = b[i:]
b = b[:8]
return uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 |
uint64(b[4])<<32 | uint64(b[5])<<40 | uint64(b[6])<<48 | uint64(b[7])<<56
}
func load3232(b []byte, i int32) uint32 {
// Help the compiler eliminate bounds checks on the read so it can be done in a single read.
b = b[i:]
b = b[:4]
return uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24
}
func load6432(b []byte, i int32) uint64 {
// Help the compiler eliminate bounds checks on the read so it can be done in a single read.
b = b[i:]
b = b[:8]
return uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 |
uint64(b[4])<<32 | uint64(b[5])<<40 | uint64(b[6])<<48 | uint64(b[7])<<56
}
func hash(u uint32) uint32 {
return (u * 0x1e35a7bd) >> tableShift
}
type tableEntry struct {
val uint32
offset int32
}
// fastGen maintains the table for matches,
// and the previous byte block for level 2.
// This is the generic implementation.
type fastGen struct {
hist []byte
cur int32
}
func (e *fastGen) addBlock(src []byte) int32 {
// check if we have space already
if len(e.hist)+len(src) > cap(e.hist) {
if cap(e.hist) == 0 {
e.hist = make([]byte, 0, allocHistory)
} else {
if cap(e.hist) < maxMatchOffset*2 {
panic("unexpected buffer size")
}
// Move down
offset := int32(len(e.hist)) - maxMatchOffset
copy(e.hist[0:maxMatchOffset], e.hist[offset:])
e.cur += offset
e.hist = e.hist[:maxMatchOffset]
}
}
s := int32(len(e.hist))
e.hist = append(e.hist, src...)
return s
}
// hash4 returns the hash of u to fit in a hash table with h bits.
// Preferably h should be a constant and should always be <32.
func hash4u(u uint32, h uint8) uint32 {
return (u * prime4bytes) >> ((32 - h) & 31)
}
type tableEntryPrev struct {
Cur tableEntry
Prev tableEntry
}
// hash4x64 returns the hash of the lowest 4 bytes of u to fit in a hash table with h bits.
// Preferably h should be a constant and should always be <32.
func hash4x64(u uint64, h uint8) uint32 {
return (uint32(u) * prime4bytes) >> ((32 - h) & 31)
}
// hash7 returns the hash of the lowest 7 bytes of u to fit in a hash table with h bits.
// Preferably h should be a constant and should always be <64.
func hash7(u uint64, h uint8) uint32 {
return uint32(((u << (64 - 56)) * prime7bytes) >> ((64 - h) & 63))
}
// hash8 returns the hash of u to fit in a hash table with h bits.
// Preferably h should be a constant and should always be <64.
func hash8(u uint64, h uint8) uint32 {
return uint32((u * prime8bytes) >> ((64 - h) & 63))
}
// hash6 returns the hash of the lowest 6 bytes of u to fit in a hash table with h bits.
// Preferably h should be a constant and should always be <64.
func hash6(u uint64, h uint8) uint32 {
return uint32(((u << (64 - 48)) * prime6bytes) >> ((64 - h) & 63))
}
// matchlen will return the match length between offsets and t in src.
// The maximum length returned is maxMatchLength - 4.
// It is assumed that s > t, that t >=0 and s < len(src).
func (e *fastGen) matchlen(s, t int32, src []byte) int32 {
if debugDecode {
if t >= s {
panic(fmt.Sprint("t >=s:", t, s))
}
if int(s) >= len(src) {
panic(fmt.Sprint("s >= len(src):", s, len(src)))
}
if t < 0 {
panic(fmt.Sprint("t < 0:", t))
}
if s-t > maxMatchOffset {
panic(fmt.Sprint(s, "-", t, "(", s-t, ") > maxMatchLength (", maxMatchOffset, ")"))
}
}
s1 := int(s) + maxMatchLength - 4
if s1 > len(src) {
s1 = len(src)
}
// Extend the match to be as long as possible.
return int32(matchLen(src[s:s1], src[t:]))
}
// matchlenLong will return the match length between offsets and t in src.
// It is assumed that s > t, that t >=0 and s < len(src).
func (e *fastGen) matchlenLong(s, t int32, src []byte) int32 {
if debugDecode {
if t >= s {
panic(fmt.Sprint("t >=s:", t, s))
}
if int(s) >= len(src) {
panic(fmt.Sprint("s >= len(src):", s, len(src)))
}
if t < 0 {
panic(fmt.Sprint("t < 0:", t))
}
if s-t > maxMatchOffset {
panic(fmt.Sprint(s, "-", t, "(", s-t, ") > maxMatchLength (", maxMatchOffset, ")"))
}
}
// Extend the match to be as long as possible.
return int32(matchLen(src[s:], src[t:]))
}
// Reset the encoding table.
func (e *fastGen) Reset() {
if cap(e.hist) < int(maxMatchOffset*8) {
l := maxMatchOffset * 8
// Make it at least 1MB.
if l < 1<<20 {
l = 1 << 20
}
e.hist = make([]byte, 0, l)
}
// We offset current position so everything will be out of reach
e.cur += maxMatchOffset + int32(len(e.hist))
e.hist = e.hist[:0]
}
// matchLen returns the maximum length.
// 'a' must be the shortest of the two.
func matchLen(a, b []byte) int {
b = b[:len(a)]
var checked int
if len(a) > 4 {
// Try 4 bytes first
if diff := load32(a, 0) ^ load32(b, 0); diff != 0 {
return bits.TrailingZeros32(diff) >> 3
}
// Switch to 8 byte matching.
checked = 4
a = a[4:]
b = b[4:]
for len(a) >= 8 {
b = b[:len(a)]
if diff := load64(a, 0) ^ load64(b, 0); diff != 0 {
return checked + (bits.TrailingZeros64(diff) >> 3)
}
checked += 8
a = a[8:]
b = b[8:]
}
}
b = b[:len(a)]
for i := range a {
if a[i] != b[i] {
return int(i) + checked
}
}
return len(a) + checked
}

544
vendor/github.com/klauspost/compress/flate/huffman_bit_writer.go generated vendored
View file

@ -35,7 +35,7 @@ const (
)
// The number of extra bits needed by length code X - LENGTH_CODES_START.
var lengthExtraBits = []int8{
var lengthExtraBits = [32]int8{
/* 257 */ 0, 0, 0,
/* 260 */ 0, 0, 0, 0, 0, 1, 1, 1, 1, 2,
/* 270 */ 2, 2, 2, 3, 3, 3, 3, 4, 4, 4,
@ -43,14 +43,14 @@ var lengthExtraBits = []int8{
}
// The length indicated by length code X - LENGTH_CODES_START.
var lengthBase = []uint32{
var lengthBase = [32]uint8{
0, 1, 2, 3, 4, 5, 6, 7, 8, 10,
12, 14, 16, 20, 24, 28, 32, 40, 48, 56,
64, 80, 96, 112, 128, 160, 192, 224, 255,
}
// offset code word extra bits.
var offsetExtraBits = []int8{
var offsetExtraBits = [64]int8{
0, 0, 0, 0, 1, 1, 2, 2, 3, 3,
4, 4, 5, 5, 6, 6, 7, 7, 8, 8,
9, 9, 10, 10, 11, 11, 12, 12, 13, 13,
@ -58,7 +58,7 @@ var offsetExtraBits = []int8{
14, 14, 15, 15, 16, 16, 17, 17, 18, 18, 19, 19, 20, 20,
}
var offsetBase = []uint32{
var offsetBase = [64]uint32{
/* normal deflate */
0x000000, 0x000001, 0x000002, 0x000003, 0x000004,
0x000006, 0x000008, 0x00000c, 0x000010, 0x000018,
@ -85,26 +85,48 @@ type huffmanBitWriter struct {
// Data waiting to be written is bytes[0:nbytes]
// and then the low nbits of bits.
bits uint64
nbits uint
bytes [bufferSize]byte
codegenFreq [codegenCodeCount]int32
nbytes int
literalFreq []int32
offsetFreq []int32
codegen []uint8
nbits uint16
nbytes uint8
literalEncoding *huffmanEncoder
offsetEncoding *huffmanEncoder
codegenEncoding *huffmanEncoder
err error
lastHeader int
// Set between 0 (reused block can be up to 2x the size)
logReusePenalty uint
lastHuffMan bool
bytes [256]byte
literalFreq [lengthCodesStart + 32]uint16
offsetFreq [32]uint16
codegenFreq [codegenCodeCount]uint16
// codegen must have an extra space for the final symbol.
codegen [literalCount + offsetCodeCount + 1]uint8
}
// Huffman reuse.
//
// The huffmanBitWriter supports reusing huffman tables and thereby combining block sections.
//
// This is controlled by several variables:
//
// If lastHeader is non-zero the Huffman table can be reused.
// This also indicates that a Huffman table has been generated that can output all
// possible symbols.
// It also indicates that an EOB has not yet been emitted, so if a new tabel is generated
// an EOB with the previous table must be written.
//
// If lastHuffMan is set, a table for outputting literals has been generated and offsets are invalid.
//
// An incoming block estimates the output size of a new table using a 'fresh' by calculating the
// optimal size and adding a penalty in 'logReusePenalty'.
// A Huffman table is not optimal, which is why we add a penalty, and generating a new table
// is slower both for compression and decompression.
func newHuffmanBitWriter(w io.Writer) *huffmanBitWriter {
return &huffmanBitWriter{
writer: w,
literalFreq: make([]int32, maxNumLit),
offsetFreq: make([]int32, offsetCodeCount),
codegen: make([]uint8, maxNumLit+offsetCodeCount+1),
literalEncoding: newHuffmanEncoder(maxNumLit),
literalEncoding: newHuffmanEncoder(literalCount),
codegenEncoding: newHuffmanEncoder(codegenCodeCount),
offsetEncoding: newHuffmanEncoder(offsetCodeCount),
}
@ -113,7 +135,42 @@ func newHuffmanBitWriter(w io.Writer) *huffmanBitWriter {
func (w *huffmanBitWriter) reset(writer io.Writer) {
w.writer = writer
w.bits, w.nbits, w.nbytes, w.err = 0, 0, 0, nil
w.bytes = [bufferSize]byte{}
w.bytes = [256]byte{}
w.lastHeader = 0
w.lastHuffMan = false
}
func (w *huffmanBitWriter) canReuse(t *tokens) (offsets, lits bool) {
offsets, lits = true, true
a := t.offHist[:offsetCodeCount]
b := w.offsetFreq[:len(a)]
for i := range a {
if b[i] == 0 && a[i] != 0 {
offsets = false
break
}
}
a = t.extraHist[:literalCount-256]
b = w.literalFreq[256:literalCount]
b = b[:len(a)]
for i := range a {
if b[i] == 0 && a[i] != 0 {
lits = false
break
}
}
if lits {
a = t.litHist[:]
b = w.literalFreq[:len(a)]
for i := range a {
if b[i] == 0 && a[i] != 0 {
lits = false
break
}
}
}
return
}
func (w *huffmanBitWriter) flush() {
@ -144,30 +201,11 @@ func (w *huffmanBitWriter) write(b []byte) {
_, w.err = w.writer.Write(b)
}
func (w *huffmanBitWriter) writeBits(b int32, nb uint) {
if w.err != nil {
return
}
w.bits |= uint64(b) << w.nbits
func (w *huffmanBitWriter) writeBits(b int32, nb uint16) {
w.bits |= uint64(b) << (w.nbits & 63)
w.nbits += nb
if w.nbits >= 48 {
bits := w.bits
w.bits >>= 48
w.nbits -= 48
n := w.nbytes
bytes := w.bytes[n : n+6]
bytes[0] = byte(bits)
bytes[1] = byte(bits >> 8)
bytes[2] = byte(bits >> 16)
bytes[3] = byte(bits >> 24)
bytes[4] = byte(bits >> 32)
bytes[5] = byte(bits >> 40)
n += 6
if n >= bufferFlushSize {
w.write(w.bytes[:n])
n = 0
}
w.nbytes = n
w.writeOutBits()
}
}
@ -213,7 +251,7 @@ func (w *huffmanBitWriter) generateCodegen(numLiterals int, numOffsets int, litE
// a copy of the frequencies, and as the place where we put the result.
// This is fine because the output is always shorter than the input used
// so far.
codegen := w.codegen // cache
codegen := w.codegen[:] // cache
// Copy the concatenated code sizes to codegen. Put a marker at the end.
cgnl := codegen[:numLiterals]
for i := range cgnl {
@ -292,30 +330,54 @@ func (w *huffmanBitWriter) generateCodegen(numLiterals int, numOffsets int, litE
codegen[outIndex] = badCode
}
// dynamicSize returns the size of dynamically encoded data in bits.
func (w *huffmanBitWriter) dynamicSize(litEnc, offEnc *huffmanEncoder, extraBits int) (size, numCodegens int) {
func (w *huffmanBitWriter) codegens() int {
numCodegens := len(w.codegenFreq)
for numCodegens > 4 && w.codegenFreq[codegenOrder[numCodegens-1]] == 0 {
numCodegens--
}
return numCodegens
}
func (w *huffmanBitWriter) headerSize() (size, numCodegens int) {
numCodegens = len(w.codegenFreq)
for numCodegens > 4 && w.codegenFreq[codegenOrder[numCodegens-1]] == 0 {
numCodegens--
}
header := 3 + 5 + 5 + 4 + (3 * numCodegens) +
return 3 + 5 + 5 + 4 + (3 * numCodegens) +
w.codegenEncoding.bitLength(w.codegenFreq[:]) +
int(w.codegenFreq[16])*2 +
int(w.codegenFreq[17])*3 +
int(w.codegenFreq[18])*7
size = header +
litEnc.bitLength(w.literalFreq) +
offEnc.bitLength(w.offsetFreq) +
extraBits
int(w.codegenFreq[18])*7, numCodegens
}
// dynamicSize returns the size of dynamically encoded data in bits.
func (w *huffmanBitWriter) dynamicSize(litEnc, offEnc *huffmanEncoder, extraBits int) (size, numCodegens int) {
header, numCodegens := w.headerSize()
size = header +
litEnc.bitLength(w.literalFreq[:]) +
offEnc.bitLength(w.offsetFreq[:]) +
extraBits
return size, numCodegens
}
// extraBitSize will return the number of bits that will be written
// as "extra" bits on matches.
func (w *huffmanBitWriter) extraBitSize() int {
total := 0
for i, n := range w.literalFreq[257:literalCount] {
total += int(n) * int(lengthExtraBits[i&31])
}
for i, n := range w.offsetFreq[:offsetCodeCount] {
total += int(n) * int(offsetExtraBits[i&31])
}
return total
}
// fixedSize returns the size of dynamically encoded data in bits.
func (w *huffmanBitWriter) fixedSize(extraBits int) int {
return 3 +
fixedLiteralEncoding.bitLength(w.literalFreq) +
fixedOffsetEncoding.bitLength(w.offsetFreq) +
fixedLiteralEncoding.bitLength(w.literalFreq[:]) +
fixedOffsetEncoding.bitLength(w.offsetFreq[:]) +
extraBits
}
@ -333,32 +395,38 @@ func (w *huffmanBitWriter) storedSize(in []byte) (int, bool) {
}
func (w *huffmanBitWriter) writeCode(c hcode) {
if w.err != nil {
return
}
// The function does not get inlined if we "& 63" the shift.
w.bits |= uint64(c.code) << w.nbits
w.nbits += uint(c.len)
w.nbits += c.len
if w.nbits >= 48 {
bits := w.bits
w.bits >>= 48
w.nbits -= 48
n := w.nbytes
bytes := w.bytes[n : n+6]
bytes[0] = byte(bits)
bytes[1] = byte(bits >> 8)
bytes[2] = byte(bits >> 16)
bytes[3] = byte(bits >> 24)
bytes[4] = byte(bits >> 32)
bytes[5] = byte(bits >> 40)
n += 6
if n >= bufferFlushSize {
w.write(w.bytes[:n])
n = 0
}
w.nbytes = n
w.writeOutBits()
}
}
// writeOutBits will write bits to the buffer.
func (w *huffmanBitWriter) writeOutBits() {
bits := w.bits
w.bits >>= 48
w.nbits -= 48
n := w.nbytes
w.bytes[n] = byte(bits)
w.bytes[n+1] = byte(bits >> 8)
w.bytes[n+2] = byte(bits >> 16)
w.bytes[n+3] = byte(bits >> 24)
w.bytes[n+4] = byte(bits >> 32)
w.bytes[n+5] = byte(bits >> 40)
n += 6
if n >= bufferFlushSize {
if w.err != nil {
n = 0
return
}
w.write(w.bytes[:n])
n = 0
}
w.nbytes = n
}
// Write the header of a dynamic Huffman block to the output stream.
//
// numLiterals The number of literals specified in codegen
@ -412,6 +480,11 @@ func (w *huffmanBitWriter) writeStoredHeader(length int, isEof bool) {
if w.err != nil {
return
}
if w.lastHeader > 0 {
// We owe an EOB
w.writeCode(w.literalEncoding.codes[endBlockMarker])
w.lastHeader = 0
}
var flag int32
if isEof {
flag = 1
@ -426,6 +499,12 @@ func (w *huffmanBitWriter) writeFixedHeader(isEof bool) {
if w.err != nil {
return
}
if w.lastHeader > 0 {
// We owe an EOB
w.writeCode(w.literalEncoding.codes[endBlockMarker])
w.lastHeader = 0
}
// Indicate that we are a fixed Huffman block
var value int32 = 2
if isEof {
@ -439,29 +518,23 @@ func (w *huffmanBitWriter) writeFixedHeader(isEof bool) {
// is larger than the original bytes, the data will be written as a
// stored block.
// If the input is nil, the tokens will always be Huffman encoded.
func (w *huffmanBitWriter) writeBlock(tokens []token, eof bool, input []byte) {
func (w *huffmanBitWriter) writeBlock(tokens *tokens, eof bool, input []byte) {
if w.err != nil {
return
}
tokens = append(tokens, endBlockMarker)
numLiterals, numOffsets := w.indexTokens(tokens)
tokens.AddEOB()
if w.lastHeader > 0 {
// We owe an EOB
w.writeCode(w.literalEncoding.codes[endBlockMarker])
w.lastHeader = 0
}
numLiterals, numOffsets := w.indexTokens(tokens, false)
w.generate(tokens)
var extraBits int
storedSize, storable := w.storedSize(input)
if storable {
// We only bother calculating the costs of the extra bits required by
// the length of offset fields (which will be the same for both fixed
// and dynamic encoding), if we need to compare those two encodings
// against stored encoding.
for lengthCode := lengthCodesStart + 8; lengthCode < numLiterals; lengthCode++ {
// First eight length codes have extra size = 0.
extraBits += int(w.literalFreq[lengthCode]) * int(lengthExtraBits[lengthCode-lengthCodesStart])
}
for offsetCode := 4; offsetCode < numOffsets; offsetCode++ {
// First four offset codes have extra size = 0.
extraBits += int(w.offsetFreq[offsetCode]) * int(offsetExtraBits[offsetCode])
}
extraBits = w.extraBitSize()
}
// Figure out smallest code.
@ -500,7 +573,7 @@ func (w *huffmanBitWriter) writeBlock(tokens []token, eof bool, input []byte) {
}
// Write the tokens.
w.writeTokens(tokens, literalEncoding.codes, offsetEncoding.codes)
w.writeTokens(tokens.Slice(), literalEncoding.codes, offsetEncoding.codes)
}
// writeBlockDynamic encodes a block using a dynamic Huffman table.
@ -508,57 +581,103 @@ func (w *huffmanBitWriter) writeBlock(tokens []token, eof bool, input []byte) {
// histogram distribution.
// If input is supplied and the compression savings are below 1/16th of the
// input size the block is stored.
func (w *huffmanBitWriter) writeBlockDynamic(tokens []token, eof bool, input []byte) {
func (w *huffmanBitWriter) writeBlockDynamic(tokens *tokens, eof bool, input []byte, sync bool) {
if w.err != nil {
return
}
tokens = append(tokens, endBlockMarker)
numLiterals, numOffsets := w.indexTokens(tokens)
// Generate codegen and codegenFrequencies, which indicates how to encode
// the literalEncoding and the offsetEncoding.
w.generateCodegen(numLiterals, numOffsets, w.literalEncoding, w.offsetEncoding)
w.codegenEncoding.generate(w.codegenFreq[:], 7)
size, numCodegens := w.dynamicSize(w.literalEncoding, w.offsetEncoding, 0)
// Store bytes, if we don't get a reasonable improvement.
if ssize, storable := w.storedSize(input); storable && ssize < (size+size>>4) {
w.writeStoredHeader(len(input), eof)
w.writeBytes(input)
return
sync = sync || eof
if sync {
tokens.AddEOB()
}
// Write Huffman table.
w.writeDynamicHeader(numLiterals, numOffsets, numCodegens, eof)
// We cannot reuse pure huffman table.
if w.lastHuffMan && w.lastHeader > 0 {
// We will not try to reuse.
w.writeCode(w.literalEncoding.codes[endBlockMarker])
w.lastHeader = 0
w.lastHuffMan = false
}
if !sync {
tokens.Fill()
}
numLiterals, numOffsets := w.indexTokens(tokens, !sync)
var size int
// Check if we should reuse.
if w.lastHeader > 0 {
// Estimate size for using a new table
newSize := w.lastHeader + tokens.EstimatedBits()
// The estimated size is calculated as an optimal table.
// We add a penalty to make it more realistic and re-use a bit more.
newSize += newSize >> (w.logReusePenalty & 31)
extra := w.extraBitSize()
reuseSize, _ := w.dynamicSize(w.literalEncoding, w.offsetEncoding, extra)
// Check if a new table is better.
if newSize < reuseSize {
// Write the EOB we owe.
w.writeCode(w.literalEncoding.codes[endBlockMarker])
size = newSize
w.lastHeader = 0
} else {
size = reuseSize
}
// Check if we get a reasonable size decrease.
if ssize, storable := w.storedSize(input); storable && ssize < (size+size>>4) {
w.writeStoredHeader(len(input), eof)
w.writeBytes(input)
w.lastHeader = 0
return
}
}
// We want a new block/table
if w.lastHeader == 0 {
w.generate(tokens)
// Generate codegen and codegenFrequencies, which indicates how to encode
// the literalEncoding and the offsetEncoding.
w.generateCodegen(numLiterals, numOffsets, w.literalEncoding, w.offsetEncoding)
w.codegenEncoding.generate(w.codegenFreq[:], 7)
var numCodegens int
size, numCodegens = w.dynamicSize(w.literalEncoding, w.offsetEncoding, w.extraBitSize())
// Store bytes, if we don't get a reasonable improvement.
if ssize, storable := w.storedSize(input); storable && ssize < (size+size>>4) {
w.writeStoredHeader(len(input), eof)
w.writeBytes(input)
w.lastHeader = 0
return
}
// Write Huffman table.
w.writeDynamicHeader(numLiterals, numOffsets, numCodegens, eof)
w.lastHeader, _ = w.headerSize()
w.lastHuffMan = false
}
if sync {
w.lastHeader = 0
}
// Write the tokens.
w.writeTokens(tokens, w.literalEncoding.codes, w.offsetEncoding.codes)
w.writeTokens(tokens.Slice(), w.literalEncoding.codes, w.offsetEncoding.codes)
}
// indexTokens indexes a slice of tokens, and updates
// literalFreq and offsetFreq, and generates literalEncoding
// and offsetEncoding.
// The number of literal and offset tokens is returned.
func (w *huffmanBitWriter) indexTokens(tokens []token) (numLiterals, numOffsets int) {
for i := range w.literalFreq {
w.literalFreq[i] = 0
}
for i := range w.offsetFreq {
w.offsetFreq[i] = 0
}
func (w *huffmanBitWriter) indexTokens(t *tokens, filled bool) (numLiterals, numOffsets int) {
copy(w.literalFreq[:], t.litHist[:])
copy(w.literalFreq[256:], t.extraHist[:])
copy(w.offsetFreq[:], t.offHist[:offsetCodeCount])
for _, t := range tokens {
if t < matchType {
w.literalFreq[t.literal()]++
continue
}
length := t.length()
offset := t.offset()
w.literalFreq[lengthCodesStart+lengthCode(length)]++
w.offsetFreq[offsetCode(offset)]++
if t.n == 0 {
return
}
if filled {
return maxNumLit, maxNumDist
}
// get the number of literals
numLiterals = len(w.literalFreq)
for w.literalFreq[numLiterals-1] == 0 {
@ -575,41 +694,85 @@ func (w *huffmanBitWriter) indexTokens(tokens []token) (numLiterals, numOffsets
w.offsetFreq[0] = 1
numOffsets = 1
}
w.literalEncoding.generate(w.literalFreq, 15)
w.offsetEncoding.generate(w.offsetFreq, 15)
return
}
func (w *huffmanBitWriter) generate(t *tokens) {
w.literalEncoding.generate(w.literalFreq[:literalCount], 15)
w.offsetEncoding.generate(w.offsetFreq[:offsetCodeCount], 15)
}
// writeTokens writes a slice of tokens to the output.
// codes for literal and offset encoding must be supplied.
func (w *huffmanBitWriter) writeTokens(tokens []token, leCodes, oeCodes []hcode) {
if w.err != nil {
return
}
if len(tokens) == 0 {
return
}
// Only last token should be endBlockMarker.
var deferEOB bool
if tokens[len(tokens)-1] == endBlockMarker {
tokens = tokens[:len(tokens)-1]
deferEOB = true
}
// Create slices up to the next power of two to avoid bounds checks.
lits := leCodes[:256]
offs := oeCodes[:32]
lengths := leCodes[lengthCodesStart:]
lengths = lengths[:32]
for _, t := range tokens {
if t < matchType {
w.writeCode(leCodes[t.literal()])
w.writeCode(lits[t.literal()])
continue
}
// Write the length
length := t.length()
lengthCode := lengthCode(length)
w.writeCode(leCodes[lengthCode+lengthCodesStart])
extraLengthBits := uint(lengthExtraBits[lengthCode])
if false {
w.writeCode(lengths[lengthCode&31])
} else {
// inlined
c := lengths[lengthCode&31]
w.bits |= uint64(c.code) << (w.nbits & 63)
w.nbits += c.len
if w.nbits >= 48 {
w.writeOutBits()
}
}
extraLengthBits := uint16(lengthExtraBits[lengthCode&31])
if extraLengthBits > 0 {
extraLength := int32(length - lengthBase[lengthCode])
extraLength := int32(length - lengthBase[lengthCode&31])
w.writeBits(extraLength, extraLengthBits)
}
// Write the offset
offset := t.offset()
offsetCode := offsetCode(offset)
w.writeCode(oeCodes[offsetCode])
extraOffsetBits := uint(offsetExtraBits[offsetCode])
if false {
w.writeCode(offs[offsetCode&31])
} else {
// inlined
c := offs[offsetCode&31]
w.bits |= uint64(c.code) << (w.nbits & 63)
w.nbits += c.len
if w.nbits >= 48 {
w.writeOutBits()
}
}
extraOffsetBits := uint16(offsetExtraBits[offsetCode&63])
if extraOffsetBits > 0 {
extraOffset := int32(offset - offsetBase[offsetCode])
extraOffset := int32(offset - offsetBase[offsetCode&63])
w.writeBits(extraOffset, extraOffsetBits)
}
}
if deferEOB {
w.writeCode(leCodes[endBlockMarker])
}
}
// huffOffset is a static offset encoder used for huffman only encoding.
@ -620,82 +783,99 @@ func init() {
w := newHuffmanBitWriter(nil)
w.offsetFreq[0] = 1
huffOffset = newHuffmanEncoder(offsetCodeCount)
huffOffset.generate(w.offsetFreq, 15)
huffOffset.generate(w.offsetFreq[:offsetCodeCount], 15)
}
// writeBlockHuff encodes a block of bytes as either
// Huffman encoded literals or uncompressed bytes if the
// results only gains very little from compression.
func (w *huffmanBitWriter) writeBlockHuff(eof bool, input []byte) {
func (w *huffmanBitWriter) writeBlockHuff(eof bool, input []byte, sync bool) {
if w.err != nil {
return
}
// Clear histogram
for i := range w.literalFreq {
for i := range w.literalFreq[:] {
w.literalFreq[i] = 0
}
if !w.lastHuffMan {
for i := range w.offsetFreq[:] {
w.offsetFreq[i] = 0
}
}
// Add everything as literals
histogram(input, w.literalFreq)
w.literalFreq[endBlockMarker] = 1
const numLiterals = endBlockMarker + 1
const numOffsets = 1
w.literalEncoding.generate(w.literalFreq, 15)
// Figure out smallest code.
// Always use dynamic Huffman or Store
var numCodegens int
// Generate codegen and codegenFrequencies, which indicates how to encode
// the literalEncoding and the offsetEncoding.
w.generateCodegen(numLiterals, numOffsets, w.literalEncoding, huffOffset)
w.codegenEncoding.generate(w.codegenFreq[:], 7)
size, numCodegens := w.dynamicSize(w.literalEncoding, huffOffset, 0)
estBits := histogramSize(input, w.literalFreq[:], !eof && !sync) + 15
// Store bytes, if we don't get a reasonable improvement.
if ssize, storable := w.storedSize(input); storable && ssize < (size+size>>4) {
ssize, storable := w.storedSize(input)
if storable && ssize < (estBits+estBits>>4) {
w.writeStoredHeader(len(input), eof)
w.writeBytes(input)
return
}
// Huffman.
w.writeDynamicHeader(numLiterals, numOffsets, numCodegens, eof)
if w.lastHeader > 0 {
size, _ := w.dynamicSize(w.literalEncoding, huffOffset, w.lastHeader)
estBits += estBits >> (w.logReusePenalty)
if estBits < size {
// We owe an EOB
w.writeCode(w.literalEncoding.codes[endBlockMarker])
w.lastHeader = 0
}
}
const numLiterals = endBlockMarker + 1
const numOffsets = 1
if w.lastHeader == 0 {
w.literalFreq[endBlockMarker] = 1
w.literalEncoding.generate(w.literalFreq[:numLiterals], 15)
// Generate codegen and codegenFrequencies, which indicates how to encode
// the literalEncoding and the offsetEncoding.
w.generateCodegen(numLiterals, numOffsets, w.literalEncoding, huffOffset)
w.codegenEncoding.generate(w.codegenFreq[:], 7)
numCodegens := w.codegens()
// Huffman.
w.writeDynamicHeader(numLiterals, numOffsets, numCodegens, eof)
w.lastHuffMan = true
w.lastHeader, _ = w.headerSize()
}
encoding := w.literalEncoding.codes[:257]
n := w.nbytes
for _, t := range input {
// Bitwriting inlined, ~30% speedup
c := encoding[t]
w.bits |= uint64(c.code) << w.nbits
w.nbits += uint(c.len)
if w.nbits < 48 {
continue
w.bits |= uint64(c.code) << ((w.nbits) & 63)
w.nbits += c.len
if w.nbits >= 48 {
bits := w.bits
w.bits >>= 48
w.nbits -= 48
n := w.nbytes
w.bytes[n] = byte(bits)
w.bytes[n+1] = byte(bits >> 8)
w.bytes[n+2] = byte(bits >> 16)
w.bytes[n+3] = byte(bits >> 24)
w.bytes[n+4] = byte(bits >> 32)
w.bytes[n+5] = byte(bits >> 40)
n += 6
if n >= bufferFlushSize {
if w.err != nil {
n = 0
return
}
w.write(w.bytes[:n])
n = 0
}
w.nbytes = n
}
// Store 6 bytes
bits := w.bits
w.bits >>= 48
w.nbits -= 48
bytes := w.bytes[n : n+6]
bytes[0] = byte(bits)
bytes[1] = byte(bits >> 8)
bytes[2] = byte(bits >> 16)
bytes[3] = byte(bits >> 24)
bytes[4] = byte(bits >> 32)
bytes[5] = byte(bits >> 40)
n += 6
if n < bufferFlushSize {
continue
}
w.write(w.bytes[:n])
if w.err != nil {
return // Return early in the event of write failures
}
n = 0
}
w.nbytes = n
w.writeCode(encoding[endBlockMarker])
if eof || sync {
w.writeCode(encoding[endBlockMarker])
w.lastHeader = 0
w.lastHuffMan = false
}
}

72
vendor/github.com/klauspost/compress/flate/huffman_code.go generated vendored
View file

@ -6,9 +6,16 @@ package flate
import (
"math"
"math/bits"
"sort"
)
const (
maxBitsLimit = 16
// number of valid literals
literalCount = 286
)
// hcode is a huffman code with a bit code and bit length.
type hcode struct {
code, len uint16
@ -24,7 +31,7 @@ type huffmanEncoder struct {
type literalNode struct {
literal uint16
freq int32
freq uint16
}
// A levelInfo describes the state of the constructed tree for a given depth.
@ -53,18 +60,24 @@ func (h *hcode) set(code uint16, length uint16) {
h.code = code
}
func maxNode() literalNode { return literalNode{math.MaxUint16, math.MaxInt32} }
func reverseBits(number uint16, bitLength byte) uint16 {
return bits.Reverse16(number << ((16 - bitLength) & 15))
}
func maxNode() literalNode { return literalNode{math.MaxUint16, math.MaxUint16} }
func newHuffmanEncoder(size int) *huffmanEncoder {
return &huffmanEncoder{codes: make([]hcode, size)}
// Make capacity to next power of two.
c := uint(bits.Len32(uint32(size - 1)))
return &huffmanEncoder{codes: make([]hcode, size, 1<<c)}
}
// Generates a HuffmanCode corresponding to the fixed literal table
func generateFixedLiteralEncoding() *huffmanEncoder {
h := newHuffmanEncoder(maxNumLit)
h := newHuffmanEncoder(literalCount)
codes := h.codes
var ch uint16
for ch = 0; ch < maxNumLit; ch++ {
for ch = 0; ch < literalCount; ch++ {
var bits uint16
var size uint16
switch {
@ -105,7 +118,7 @@ func generateFixedOffsetEncoding() *huffmanEncoder {
var fixedLiteralEncoding *huffmanEncoder = generateFixedLiteralEncoding()
var fixedOffsetEncoding *huffmanEncoder = generateFixedOffsetEncoding()
func (h *huffmanEncoder) bitLength(freq []int32) int {
func (h *huffmanEncoder) bitLength(freq []uint16) int {
var total int
for i, f := range freq {
if f != 0 {
@ -115,8 +128,6 @@ func (h *huffmanEncoder) bitLength(freq []int32) int {
return total
}
const maxBitsLimit = 16
// Return the number of literals assigned to each bit size in the Huffman encoding
//
// This method is only called when list.length >= 3
@ -160,9 +171,9 @@ func (h *huffmanEncoder) bitCounts(list []literalNode, maxBits int32) []int32 {
// We initialize the levels as if we had already figured this out.
levels[level] = levelInfo{
level: level,
lastFreq: list[1].freq,
nextCharFreq: list[2].freq,
nextPairFreq: list[0].freq + list[1].freq,
lastFreq: int32(list[1].freq),
nextCharFreq: int32(list[2].freq),
nextPairFreq: int32(list[0].freq) + int32(list[1].freq),
}
leafCounts[level][level] = 2
if level == 1 {
@ -194,7 +205,12 @@ func (h *huffmanEncoder) bitCounts(list []literalNode, maxBits int32) []int32 {
l.lastFreq = l.nextCharFreq
// Lower leafCounts are the same of the previous node.
leafCounts[level][level] = n
l.nextCharFreq = list[n].freq
e := list[n]
if e.literal < math.MaxUint16 {
l.nextCharFreq = int32(e.freq)
} else {
l.nextCharFreq = math.MaxInt32
}
} else {
// The next item on this row is a pair from the previous row.
// nextPairFreq isn't valid until we generate two
@ -270,12 +286,12 @@ func (h *huffmanEncoder) assignEncodingAndSize(bitCount []int32, list []literalN
//
// freq An array of frequencies, in which frequency[i] gives the frequency of literal i.
// maxBits The maximum number of bits to use for any literal.
func (h *huffmanEncoder) generate(freq []int32, maxBits int32) {
func (h *huffmanEncoder) generate(freq []uint16, maxBits int32) {
if h.freqcache == nil {
// Allocate a reusable buffer with the longest possible frequency table.
// Possible lengths are codegenCodeCount, offsetCodeCount and maxNumLit.
// The largest of these is maxNumLit, so we allocate for that case.
h.freqcache = make([]literalNode, maxNumLit+1)
// Possible lengths are codegenCodeCount, offsetCodeCount and literalCount.
// The largest of these is literalCount, so we allocate for that case.
h.freqcache = make([]literalNode, literalCount+1)
}
list := h.freqcache[:len(freq)+1]
// Number of non-zero literals
@ -342,3 +358,27 @@ func (s byFreq) Less(i, j int) bool {
}
func (s byFreq) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
// histogramSize accumulates a histogram of b in h.
// An estimated size in bits is returned.
// Unassigned values are assigned '1' in the histogram.
// len(h) must be >= 256, and h's elements must be all zeroes.
func histogramSize(b []byte, h []uint16, fill bool) int {
h = h[:256]
for _, t := range b {
h[t]++
}
invTotal := 1.0 / float64(len(b))
shannon := 0.0
single := math.Ceil(-math.Log2(invTotal))
for i, v := range h[:] {
if v > 0 {
n := float64(v)
shannon += math.Ceil(-math.Log2(n*invTotal) * n)
} else if fill {
shannon += single
h[i] = 1
}
}
return int(shannon + 0.99)
}

169
vendor/github.com/klauspost/compress/flate/inflate.go generated vendored
View file

@ -9,19 +9,24 @@ package flate
import (
"bufio"
"fmt"
"io"
"math/bits"
"strconv"
"sync"
)
const (
maxCodeLen = 16 // max length of Huffman code
maxCodeLen = 16 // max length of Huffman code
maxCodeLenMask = 15 // mask for max length of Huffman code
// The next three numbers come from the RFC section 3.2.7, with the
// additional proviso in section 3.2.5 which implies that distance codes
// 30 and 31 should never occur in compressed data.
maxNumLit = 286
maxNumDist = 30
numCodes = 19 // number of codes in Huffman meta-code
debugDecode = false
)
// Initialize the fixedHuffmanDecoder only once upon first use.
@ -101,10 +106,10 @@ const (
)
type huffmanDecoder struct {
min int // the minimum code length
chunks [huffmanNumChunks]uint32 // chunks as described above
links [][]uint32 // overflow links
linkMask uint32 // mask the width of the link table
min int // the minimum code length
chunks *[huffmanNumChunks]uint16 // chunks as described above
links [][]uint16 // overflow links
linkMask uint32 // mask the width of the link table
}
// Initialize Huffman decoding tables from array of code lengths.
@ -112,21 +117,24 @@ type huffmanDecoder struct {
// tree (i.e., neither over-subscribed nor under-subscribed). The exception is a
// degenerate case where the tree has only a single symbol with length 1. Empty
// trees are permitted.
func (h *huffmanDecoder) init(bits []int) bool {
func (h *huffmanDecoder) init(lengths []int) bool {
// Sanity enables additional runtime tests during Huffman
// table construction. It's intended to be used during
// development to supplement the currently ad-hoc unit tests.
const sanity = false
if h.chunks == nil {
h.chunks = &[huffmanNumChunks]uint16{}
}
if h.min != 0 {
*h = huffmanDecoder{}
*h = huffmanDecoder{chunks: h.chunks, links: h.links}
}
// Count number of codes of each length,
// compute min and max length.
var count [maxCodeLen]int
var min, max int
for _, n := range bits {
for _, n := range lengths {
if n == 0 {
continue
}
@ -136,7 +144,7 @@ func (h *huffmanDecoder) init(bits []int) bool {
if n > max {
max = n
}
count[n]++
count[n&maxCodeLenMask]++
}
// Empty tree. The decompressor.huffSym function will fail later if the tree
@ -154,8 +162,8 @@ func (h *huffmanDecoder) init(bits []int) bool {
var nextcode [maxCodeLen]int
for i := min; i <= max; i++ {
code <<= 1
nextcode[i] = code
code += count[i]
nextcode[i&maxCodeLenMask] = code
code += count[i&maxCodeLenMask]
}
// Check that the coding is complete (i.e., that we've
@ -164,37 +172,56 @@ func (h *huffmanDecoder) init(bits []int) bool {
// accept degenerate single-code codings. See also
// TestDegenerateHuffmanCoding.
if code != 1<<uint(max) && !(code == 1 && max == 1) {
if debugDecode {
fmt.Println("coding failed, code, max:", code, max, code == 1<<uint(max), code == 1 && max == 1, "(one should be true)")
}
return false
}
h.min = min
chunks := h.chunks[:]
for i := range chunks {
chunks[i] = 0
}
if max > huffmanChunkBits {
numLinks := 1 << (uint(max) - huffmanChunkBits)
h.linkMask = uint32(numLinks - 1)
// create link tables
link := nextcode[huffmanChunkBits+1] >> 1
h.links = make([][]uint32, huffmanNumChunks-link)
if cap(h.links) < huffmanNumChunks-link {
h.links = make([][]uint16, huffmanNumChunks-link)
} else {
h.links = h.links[:huffmanNumChunks-link]
}
for j := uint(link); j < huffmanNumChunks; j++ {
reverse := int(reverseByte[j>>8]) | int(reverseByte[j&0xff])<<8
reverse := int(bits.Reverse16(uint16(j)))
reverse >>= uint(16 - huffmanChunkBits)
off := j - uint(link)
if sanity && h.chunks[reverse] != 0 {
panic("impossible: overwriting existing chunk")
}
h.chunks[reverse] = uint32(off<<huffmanValueShift | (huffmanChunkBits + 1))
h.links[off] = make([]uint32, numLinks)
h.chunks[reverse] = uint16(off<<huffmanValueShift | (huffmanChunkBits + 1))
if cap(h.links[off]) < numLinks {
h.links[off] = make([]uint16, numLinks)
} else {
links := h.links[off][:0]
h.links[off] = links[:numLinks]
}
}
} else {
h.links = h.links[:0]
}
for i, n := range bits {
for i, n := range lengths {
if n == 0 {
continue
}
code := nextcode[n]
nextcode[n]++
chunk := uint32(i<<huffmanValueShift | n)
reverse := int(reverseByte[code>>8]) | int(reverseByte[code&0xff])<<8
chunk := uint16(i<<huffmanValueShift | n)
reverse := int(bits.Reverse16(uint16(code)))
reverse >>= uint(16 - n)
if n <= huffmanChunkBits {
for off := reverse; off < len(h.chunks); off += 1 << uint(n) {
@ -326,6 +353,9 @@ func (f *decompressor) nextBlock() {
f.huffmanBlock()
default:
// 3 is reserved.
if debugDecode {
fmt.Println("reserved data block encountered")
}
f.err = CorruptInputError(f.roffset)
}
}
@ -404,11 +434,17 @@ func (f *decompressor) readHuffman() error {
}
nlit := int(f.b&0x1F) + 257
if nlit > maxNumLit {
if debugDecode {
fmt.Println("nlit > maxNumLit", nlit)
}
return CorruptInputError(f.roffset)
}
f.b >>= 5
ndist := int(f.b&0x1F) + 1
if ndist > maxNumDist {
if debugDecode {
fmt.Println("ndist > maxNumDist", ndist)
}
return CorruptInputError(f.roffset)
}
f.b >>= 5
@ -432,6 +468,9 @@ func (f *decompressor) readHuffman() error {
f.codebits[codeOrder[i]] = 0
}
if !f.h1.init(f.codebits[0:]) {
if debugDecode {
fmt.Println("init codebits failed")
}
return CorruptInputError(f.roffset)
}
@ -459,6 +498,9 @@ func (f *decompressor) readHuffman() error {
rep = 3
nb = 2
if i == 0 {
if debugDecode {
fmt.Println("i==0")
}
return CorruptInputError(f.roffset)
}
b = f.bits[i-1]
@ -473,6 +515,9 @@ func (f *decompressor) readHuffman() error {
}
for f.nb < nb {
if err := f.moreBits(); err != nil {
if debugDecode {
fmt.Println("morebits:", err)
}
return err
}
}
@ -480,6 +525,9 @@ func (f *decompressor) readHuffman() error {
f.b >>= nb
f.nb -= nb
if i+rep > n {
if debugDecode {
fmt.Println("i+rep > n", i, rep, n)
}
return CorruptInputError(f.roffset)
}
for j := 0; j < rep; j++ {
@ -489,6 +537,9 @@ func (f *decompressor) readHuffman() error {
}
if !f.h1.init(f.bits[0:nlit]) || !f.h2.init(f.bits[nlit:nlit+ndist]) {
if debugDecode {
fmt.Println("init2 failed")
}
return CorruptInputError(f.roffset)
}
@ -566,12 +617,18 @@ readLiteral:
length = 258
n = 0
default:
if debugDecode {
fmt.Println(v, ">= maxNumLit")
}
f.err = CorruptInputError(f.roffset)
return
}
if n > 0 {
for f.nb < n {
if err = f.moreBits(); err != nil {
if debugDecode {
fmt.Println("morebits n>0:", err)
}
f.err = err
return
}
@ -585,15 +642,21 @@ readLiteral:
if f.hd == nil {
for f.nb < 5 {
if err = f.moreBits(); err != nil {
if debugDecode {
fmt.Println("morebits f.nb<5:", err)
}
f.err = err
return
}
}
dist = int(reverseByte[(f.b&0x1F)<<3])
dist = int(bits.Reverse8(uint8(f.b & 0x1F << 3)))
f.b >>= 5
f.nb -= 5
} else {
if dist, err = f.huffSym(f.hd); err != nil {
if debugDecode {
fmt.Println("huffsym:", err)
}
f.err = err
return
}
@ -608,6 +671,9 @@ readLiteral:
extra := (dist & 1) << nb
for f.nb < nb {
if err = f.moreBits(); err != nil {
if debugDecode {
fmt.Println("morebits f.nb<nb:", err)
}
f.err = err
return
}
@ -617,12 +683,18 @@ readLiteral:
f.nb -= nb
dist = 1<<(nb+1) + 1 + extra
default:
if debugDecode {
fmt.Println("dist too big:", dist, maxNumDist)
}
f.err = CorruptInputError(f.roffset)
return
}
// No check on length; encoding can be prescient.
if dist > f.dict.histSize() {
if debugDecode {
fmt.Println("dist > f.dict.histSize():", dist, f.dict.histSize())
}
f.err = CorruptInputError(f.roffset)
return
}
@ -661,15 +733,15 @@ func (f *decompressor) dataBlock() {
nr, err := io.ReadFull(f.r, f.buf[0:4])
f.roffset += int64(nr)
if err != nil {
if err == io.EOF {
err = io.ErrUnexpectedEOF
}
f.err = err
f.err = noEOF(err)
return
}
n := int(f.buf[0]) | int(f.buf[1])<<8
nn := int(f.buf[2]) | int(f.buf[3])<<8
if uint16(nn) != uint16(^n) {
if debugDecode {
fmt.Println("uint16(nn) != uint16(^n)", nn, ^n)
}
f.err = CorruptInputError(f.roffset)
return
}
@ -697,10 +769,7 @@ func (f *decompressor) copyData() {
f.copyLen -= cnt
f.dict.writeMark(cnt)
if err != nil {
if err == io.EOF {
err = io.ErrUnexpectedEOF
}
f.err = err
f.err = noEOF(err)
return
}
@ -722,13 +791,18 @@ func (f *decompressor) finishBlock() {
f.step = (*decompressor).nextBlock
}
// noEOF returns err, unless err == io.EOF, in which case it returns io.ErrUnexpectedEOF.
func noEOF(e error) error {
if e == io.EOF {
return io.ErrUnexpectedEOF
}
return e
}
func (f *decompressor) moreBits() error {
c, err := f.r.ReadByte()
if err != nil {
if err == io.EOF {
err = io.ErrUnexpectedEOF
}
return err
return noEOF(err)
}
f.roffset++
f.b |= uint32(c) << f.nb
@ -743,25 +817,40 @@ func (f *decompressor) huffSym(h *huffmanDecoder) (int, error) {
// cases, the chunks slice will be 0 for the invalid sequence, leading it
// satisfy the n == 0 check below.
n := uint(h.min)
// Optimization. Compiler isn't smart enough to keep f.b,f.nb in registers,
// but is smart enough to keep local variables in registers, so use nb and b,
// inline call to moreBits and reassign b,nb back to f on return.
nb, b := f.nb, f.b
for {
for f.nb < n {
if err := f.moreBits(); err != nil {
return 0, err
for nb < n {
c, err := f.r.ReadByte()
if err != nil {
f.b = b
f.nb = nb
return 0, noEOF(err)
}
f.roffset++
b |= uint32(c) << (nb & 31)
nb += 8
}
chunk := h.chunks[f.b&(huffmanNumChunks-1)]
chunk := h.chunks[b&(huffmanNumChunks-1)]
n = uint(chunk & huffmanCountMask)
if n > huffmanChunkBits {
chunk = h.links[chunk>>huffmanValueShift][(f.b>>huffmanChunkBits)&h.linkMask]
chunk = h.links[chunk>>huffmanValueShift][(b>>huffmanChunkBits)&h.linkMask]
n = uint(chunk & huffmanCountMask)
}
if n <= f.nb {
if n <= nb {
if n == 0 {
f.b = b
f.nb = nb
if debugDecode {
fmt.Println("huffsym: n==0")
}
f.err = CorruptInputError(f.roffset)
return 0, f.err
}
f.b >>= n
f.nb -= n
f.b = b >> (n & 31)
f.nb = nb - n
return int(chunk >> huffmanValueShift), nil
}
}
@ -799,6 +888,8 @@ func (f *decompressor) Reset(r io.Reader, dict []byte) error {
r: makeReader(r),
bits: f.bits,
codebits: f.codebits,
h1: f.h1,
h2: f.h2,
dict: f.dict,
step: (*decompressor).nextBlock,
}

174
vendor/github.com/klauspost/compress/flate/level1.go generated vendored Normal file
View file

@ -0,0 +1,174 @@
package flate
// fastGen maintains the table for matches,
// and the previous byte block for level 2.
// This is the generic implementation.
type fastEncL1 struct {
fastGen
table [tableSize]tableEntry
}
// EncodeL1 uses a similar algorithm to level 1
func (e *fastEncL1) Encode(dst *tokens, src []byte) {
const (
inputMargin = 12 - 1
minNonLiteralBlockSize = 1 + 1 + inputMargin
)
// Protect against e.cur wraparound.
for e.cur >= bufferReset {
if len(e.hist) == 0 {
for i := range e.table[:] {
e.table[i] = tableEntry{}
}
e.cur = maxMatchOffset
break
}
// Shift down everything in the table that isn't already too far away.
minOff := e.cur + int32(len(e.hist)) - maxMatchOffset
for i := range e.table[:] {
v := e.table[i].offset
if v <= minOff {
v = 0
} else {
v = v - e.cur + maxMatchOffset
}
e.table[i].offset = v
}
e.cur = maxMatchOffset
}
s := e.addBlock(src)
// This check isn't in the Snappy implementation, but there, the caller
// instead of the callee handles this case.
if len(src) < minNonLiteralBlockSize {
// We do not fill the token table.
// This will be picked up by caller.
dst.n = uint16(len(src))
return
}
// Override src
src = e.hist
nextEmit := s
// sLimit is when to stop looking for offset/length copies. The inputMargin
// lets us use a fast path for emitLiteral in the main loop, while we are
// looking for copies.
sLimit := int32(len(src) - inputMargin)
// nextEmit is where in src the next emitLiteral should start from.
cv := load3232(src, s)
for {
const skipLog = 5
const doEvery = 2
nextS := s
var candidate tableEntry
for {
nextHash := hash(cv)
candidate = e.table[nextHash]
nextS = s + doEvery + (s-nextEmit)>>skipLog
if nextS > sLimit {
goto emitRemainder
}
now := load6432(src, nextS)
e.table[nextHash] = tableEntry{offset: s + e.cur, val: cv}
nextHash = hash(uint32(now))
offset := s - (candidate.offset - e.cur)
if offset < maxMatchOffset && cv == candidate.val {
e.table[nextHash] = tableEntry{offset: nextS + e.cur, val: uint32(now)}
break
}
// Do one right away...
cv = uint32(now)
s = nextS
nextS++
candidate = e.table[nextHash]
now >>= 8
e.table[nextHash] = tableEntry{offset: s + e.cur, val: cv}
offset = s - (candidate.offset - e.cur)
if offset < maxMatchOffset && cv == candidate.val {
e.table[nextHash] = tableEntry{offset: nextS + e.cur, val: uint32(now)}
break
}
cv = uint32(now)
s = nextS
}
// A 4-byte match has been found. We'll later see if more than 4 bytes
// match. But, prior to the match, src[nextEmit:s] are unmatched. Emit
// them as literal bytes.
for {
// Invariant: we have a 4-byte match at s, and no need to emit any
// literal bytes prior to s.
// Extend the 4-byte match as long as possible.
t := candidate.offset - e.cur
l := e.matchlenLong(s+4, t+4, src) + 4
// Extend backwards
for t > 0 && s > nextEmit && src[t-1] == src[s-1] {
s--
t--
l++
}
if nextEmit < s {
emitLiteral(dst, src[nextEmit:s])
}
// Save the match found
dst.AddMatchLong(l, uint32(s-t-baseMatchOffset))
s += l
nextEmit = s
if nextS >= s {
s = nextS + 1
}
if s >= sLimit {
// Index first pair after match end.
if int(s+l+4) < len(src) {
cv := load3232(src, s)
e.table[hash(cv)] = tableEntry{offset: s + e.cur, val: cv}
}
goto emitRemainder
}
// We could immediately start working at s now, but to improve
// compression we first update the hash table at s-2 and at s. If
// another emitCopy is not our next move, also calculate nextHash
// at s+1. At least on GOARCH=amd64, these three hash calculations
// are faster as one load64 call (with some shifts) instead of
// three load32 calls.
x := load6432(src, s-2)
o := e.cur + s - 2
prevHash := hash(uint32(x))
e.table[prevHash] = tableEntry{offset: o, val: uint32(x)}
x >>= 16
currHash := hash(uint32(x))
candidate = e.table[currHash]
e.table[currHash] = tableEntry{offset: o + 2, val: uint32(x)}
offset := s - (candidate.offset - e.cur)
if offset > maxMatchOffset || uint32(x) != candidate.val {
cv = uint32(x >> 8)
s++
break
}
}
}
emitRemainder:
if int(nextEmit) < len(src) {
// If nothing was added, don't encode literals.
if dst.n == 0 {
return
}
emitLiteral(dst, src[nextEmit:])
}
}

199
vendor/github.com/klauspost/compress/flate/level2.go generated vendored Normal file
View file

@ -0,0 +1,199 @@
package flate
// fastGen maintains the table for matches,
// and the previous byte block for level 2.
// This is the generic implementation.
type fastEncL2 struct {
fastGen
table [bTableSize]tableEntry
}
// EncodeL2 uses a similar algorithm to level 1, but is capable
// of matching across blocks giving better compression at a small slowdown.
func (e *fastEncL2) Encode(dst *tokens, src []byte) {
const (
inputMargin = 12 - 1
minNonLiteralBlockSize = 1 + 1 + inputMargin
)
// Protect against e.cur wraparound.
for e.cur >= bufferReset {
if len(e.hist) == 0 {
for i := range e.table[:] {
e.table[i] = tableEntry{}
}
e.cur = maxMatchOffset
break
}
// Shift down everything in the table that isn't already too far away.
minOff := e.cur + int32(len(e.hist)) - maxMatchOffset
for i := range e.table[:] {
v := e.table[i].offset
if v <= minOff {
v = 0
} else {
v = v - e.cur + maxMatchOffset
}
e.table[i].offset = v
}
e.cur = maxMatchOffset
}
s := e.addBlock(src)
// This check isn't in the Snappy implementation, but there, the caller
// instead of the callee handles this case.
if len(src) < minNonLiteralBlockSize {
// We do not fill the token table.
// This will be picked up by caller.
dst.n = uint16(len(src))
return
}
// Override src
src = e.hist
nextEmit := s
// sLimit is when to stop looking for offset/length copies. The inputMargin
// lets us use a fast path for emitLiteral in the main loop, while we are
// looking for copies.
sLimit := int32(len(src) - inputMargin)
// nextEmit is where in src the next emitLiteral should start from.
cv := load3232(src, s)
for {
// When should we start skipping if we haven't found matches in a long while.
const skipLog = 5
const doEvery = 2
nextS := s
var candidate tableEntry
for {
nextHash := hash4u(cv, bTableBits)
s = nextS
nextS = s + doEvery + (s-nextEmit)>>skipLog
if nextS > sLimit {
goto emitRemainder
}
candidate = e.table[nextHash]
now := load6432(src, nextS)
e.table[nextHash] = tableEntry{offset: s + e.cur, val: cv}
nextHash = hash4u(uint32(now), bTableBits)
offset := s - (candidate.offset - e.cur)
if offset < maxMatchOffset && cv == candidate.val {
e.table[nextHash] = tableEntry{offset: nextS + e.cur, val: uint32(now)}
break
}
// Do one right away...
cv = uint32(now)
s = nextS
nextS++
candidate = e.table[nextHash]
now >>= 8
e.table[nextHash] = tableEntry{offset: s + e.cur, val: cv}
offset = s - (candidate.offset - e.cur)
if offset < maxMatchOffset && cv == candidate.val {
break
}
cv = uint32(now)
}
// A 4-byte match has been found. We'll later see if more than 4 bytes
// match. But, prior to the match, src[nextEmit:s] are unmatched. Emit
// them as literal bytes.
// Call emitCopy, and then see if another emitCopy could be our next
// move. Repeat until we find no match for the input immediately after
// what was consumed by the last emitCopy call.
//
// If we exit this loop normally then we need to call emitLiteral next,
// though we don't yet know how big the literal will be. We handle that
// by proceeding to the next iteration of the main loop. We also can
// exit this loop via goto if we get close to exhausting the input.
for {
// Invariant: we have a 4-byte match at s, and no need to emit any
// literal bytes prior to s.
// Extend the 4-byte match as long as possible.
t := candidate.offset - e.cur
l := e.matchlenLong(s+4, t+4, src) + 4
// Extend backwards
for t > 0 && s > nextEmit && src[t-1] == src[s-1] {
s--
t--
l++
}
if nextEmit < s {
emitLiteral(dst, src[nextEmit:s])
}
dst.AddMatchLong(l, uint32(s-t-baseMatchOffset))
s += l
nextEmit = s
if nextS >= s {
s = nextS + 1
}
if s >= sLimit {
// Index first pair after match end.
if int(s+l+4) < len(src) {
cv := load3232(src, s)
e.table[hash4u(cv, bTableBits)] = tableEntry{offset: s + e.cur, val: cv}
}
goto emitRemainder
}
// Store every second hash in-between, but offset by 1.
for i := s - l + 2; i < s-5; i += 7 {
x := load6432(src, int32(i))
nextHash := hash4u(uint32(x), bTableBits)
e.table[nextHash] = tableEntry{offset: e.cur + i, val: uint32(x)}
// Skip one
x >>= 16
nextHash = hash4u(uint32(x), bTableBits)
e.table[nextHash] = tableEntry{offset: e.cur + i + 2, val: uint32(x)}
// Skip one
x >>= 16
nextHash = hash4u(uint32(x), bTableBits)
e.table[nextHash] = tableEntry{offset: e.cur + i + 4, val: uint32(x)}
}
// We could immediately start working at s now, but to improve
// compression we first update the hash table at s-2 to s. If
// another emitCopy is not our next move, also calculate nextHash
// at s+1. At least on GOARCH=amd64, these three hash calculations
// are faster as one load64 call (with some shifts) instead of
// three load32 calls.
x := load6432(src, s-2)
o := e.cur + s - 2
prevHash := hash4u(uint32(x), bTableBits)
prevHash2 := hash4u(uint32(x>>8), bTableBits)
e.table[prevHash] = tableEntry{offset: o, val: uint32(x)}
e.table[prevHash2] = tableEntry{offset: o + 1, val: uint32(x >> 8)}
currHash := hash4u(uint32(x>>16), bTableBits)
candidate = e.table[currHash]
e.table[currHash] = tableEntry{offset: o + 2, val: uint32(x >> 16)}
offset := s - (candidate.offset - e.cur)
if offset > maxMatchOffset || uint32(x>>16) != candidate.val {
cv = uint32(x >> 24)
s++
break
}
}
}
emitRemainder:
if int(nextEmit) < len(src) {
// If nothing was added, don't encode literals.
if dst.n == 0 {
return
}
emitLiteral(dst, src[nextEmit:])
}
}

225
vendor/github.com/klauspost/compress/flate/level3.go generated vendored Normal file
View file

@ -0,0 +1,225 @@
package flate
// fastEncL3
type fastEncL3 struct {
fastGen
table [tableSize]tableEntryPrev
}
// Encode uses a similar algorithm to level 2, will check up to two candidates.
func (e *fastEncL3) Encode(dst *tokens, src []byte) {
const (
inputMargin = 8 - 1
minNonLiteralBlockSize = 1 + 1 + inputMargin
)
// Protect against e.cur wraparound.
for e.cur >= bufferReset {
if len(e.hist) == 0 {
for i := range e.table[:] {
e.table[i] = tableEntryPrev{}
}
e.cur = maxMatchOffset
break
}
// Shift down everything in the table that isn't already too far away.
minOff := e.cur + int32(len(e.hist)) - maxMatchOffset
for i := range e.table[:] {
v := e.table[i]
if v.Cur.offset <= minOff {
v.Cur.offset = 0
} else {
v.Cur.offset = v.Cur.offset - e.cur + maxMatchOffset
}
if v.Prev.offset <= minOff {
v.Prev.offset = 0
} else {
v.Prev.offset = v.Prev.offset - e.cur + maxMatchOffset
}
e.table[i] = v
}
e.cur = maxMatchOffset
}
s := e.addBlock(src)
// Skip if too small.
if len(src) < minNonLiteralBlockSize {
// We do not fill the token table.
// This will be picked up by caller.
dst.n = uint16(len(src))
return
}
// Override src
src = e.hist
nextEmit := s
// sLimit is when to stop looking for offset/length copies. The inputMargin
// lets us use a fast path for emitLiteral in the main loop, while we are
// looking for copies.
sLimit := int32(len(src) - inputMargin)
// nextEmit is where in src the next emitLiteral should start from.
cv := load3232(src, s)
for {
const skipLog = 6
nextS := s
var candidate tableEntry
for {
nextHash := hash(cv)
s = nextS
nextS = s + 1 + (s-nextEmit)>>skipLog
if nextS > sLimit {
goto emitRemainder
}
candidates := e.table[nextHash]
now := load3232(src, nextS)
e.table[nextHash] = tableEntryPrev{Prev: candidates.Cur, Cur: tableEntry{offset: s + e.cur, val: cv}}
// Check both candidates
candidate = candidates.Cur
offset := s - (candidate.offset - e.cur)
if cv == candidate.val {
if offset > maxMatchOffset {
cv = now
// Previous will also be invalid, we have nothing.
continue
}
o2 := s - (candidates.Prev.offset - e.cur)
if cv != candidates.Prev.val || o2 > maxMatchOffset {
break
}
// Both match and are valid, pick longest.
l1, l2 := matchLen(src[s+4:], src[s-offset+4:]), matchLen(src[s+4:], src[s-o2+4:])
if l2 > l1 {
candidate = candidates.Prev
}
break
} else {
// We only check if value mismatches.
// Offset will always be invalid in other cases.
candidate = candidates.Prev
if cv == candidate.val {
offset := s - (candidate.offset - e.cur)
if offset <= maxMatchOffset {
break
}
}
}
cv = now
}
// Call emitCopy, and then see if another emitCopy could be our next
// move. Repeat until we find no match for the input immediately after
// what was consumed by the last emitCopy call.
//
// If we exit this loop normally then we need to call emitLiteral next,
// though we don't yet know how big the literal will be. We handle that
// by proceeding to the next iteration of the main loop. We also can
// exit this loop via goto if we get close to exhausting the input.
for {
// Invariant: we have a 4-byte match at s, and no need to emit any
// literal bytes prior to s.
// Extend the 4-byte match as long as possible.
//
t := candidate.offset - e.cur
l := e.matchlenLong(s+4, t+4, src) + 4
// Extend backwards
for t > 0 && s > nextEmit && src[t-1] == src[s-1] {
s--
t--
l++
}
if nextEmit < s {
emitLiteral(dst, src[nextEmit:s])
}
dst.AddMatchLong(l, uint32(s-t-baseMatchOffset))
s += l
nextEmit = s
if nextS >= s {
s = nextS + 1
}
if s >= sLimit {
t += l
// Index first pair after match end.
if int(t+4) < len(src) && t > 0 {
cv := load3232(src, t)
nextHash := hash(cv)
e.table[nextHash] = tableEntryPrev{
Prev: e.table[nextHash].Cur,
Cur: tableEntry{offset: e.cur + t, val: cv},
}
}
goto emitRemainder
}
// We could immediately start working at s now, but to improve
// compression we first update the hash table at s-3 to s.
x := load6432(src, s-3)
prevHash := hash(uint32(x))
e.table[prevHash] = tableEntryPrev{
Prev: e.table[prevHash].Cur,
Cur: tableEntry{offset: e.cur + s - 3, val: uint32(x)},
}
x >>= 8
prevHash = hash(uint32(x))
e.table[prevHash] = tableEntryPrev{
Prev: e.table[prevHash].Cur,
Cur: tableEntry{offset: e.cur + s - 2, val: uint32(x)},
}
x >>= 8
prevHash = hash(uint32(x))
e.table[prevHash] = tableEntryPrev{
Prev: e.table[prevHash].Cur,
Cur: tableEntry{offset: e.cur + s - 1, val: uint32(x)},
}
x >>= 8
currHash := hash(uint32(x))
candidates := e.table[currHash]
cv = uint32(x)
e.table[currHash] = tableEntryPrev{
Prev: candidates.Cur,
Cur: tableEntry{offset: s + e.cur, val: cv},
}
// Check both candidates
candidate = candidates.Cur
if cv == candidate.val {
offset := s - (candidate.offset - e.cur)
if offset <= maxMatchOffset {
continue
}
} else {
// We only check if value mismatches.
// Offset will always be invalid in other cases.
candidate = candidates.Prev
if cv == candidate.val {
offset := s - (candidate.offset - e.cur)
if offset <= maxMatchOffset {
continue
}
}
}
cv = uint32(x >> 8)
s++
break
}
}
emitRemainder:
if int(nextEmit) < len(src) {
// If nothing was added, don't encode literals.
if dst.n == 0 {
return
}
emitLiteral(dst, src[nextEmit:])
}
}

210
vendor/github.com/klauspost/compress/flate/level4.go generated vendored Normal file
View file

@ -0,0 +1,210 @@
package flate
import "fmt"
type fastEncL4 struct {
fastGen
table [tableSize]tableEntry
bTable [tableSize]tableEntry
}
func (e *fastEncL4) Encode(dst *tokens, src []byte) {
const (
inputMargin = 12 - 1
minNonLiteralBlockSize = 1 + 1 + inputMargin
)
// Protect against e.cur wraparound.
for e.cur >= bufferReset {
if len(e.hist) == 0 {
for i := range e.table[:] {
e.table[i] = tableEntry{}
}
for i := range e.bTable[:] {
e.bTable[i] = tableEntry{}
}
e.cur = maxMatchOffset
break
}
// Shift down everything in the table that isn't already too far away.
minOff := e.cur + int32(len(e.hist)) - maxMatchOffset
for i := range e.table[:] {
v := e.table[i].offset
if v <= minOff {
v = 0
} else {
v = v - e.cur + maxMatchOffset
}
e.table[i].offset = v
}
for i := range e.bTable[:] {
v := e.bTable[i].offset
if v <= minOff {
v = 0
} else {
v = v - e.cur + maxMatchOffset
}
e.bTable[i].offset = v
}
e.cur = maxMatchOffset
}
s := e.addBlock(src)
// This check isn't in the Snappy implementation, but there, the caller
// instead of the callee handles this case.
if len(src) < minNonLiteralBlockSize {
// We do not fill the token table.
// This will be picked up by caller.
dst.n = uint16(len(src))
return
}
// Override src
src = e.hist
nextEmit := s
// sLimit is when to stop looking for offset/length copies. The inputMargin
// lets us use a fast path for emitLiteral in the main loop, while we are
// looking for copies.
sLimit := int32(len(src) - inputMargin)
// nextEmit is where in src the next emitLiteral should start from.
cv := load6432(src, s)
for {
const skipLog = 6
const doEvery = 1
nextS := s
var t int32
for {
nextHashS := hash4x64(cv, tableBits)
nextHashL := hash7(cv, tableBits)
s = nextS
nextS = s + doEvery + (s-nextEmit)>>skipLog
if nextS > sLimit {
goto emitRemainder
}
// Fetch a short+long candidate
sCandidate := e.table[nextHashS]
lCandidate := e.bTable[nextHashL]
next := load6432(src, nextS)
entry := tableEntry{offset: s + e.cur, val: uint32(cv)}
e.table[nextHashS] = entry
e.bTable[nextHashL] = entry
t = lCandidate.offset - e.cur
if s-t < maxMatchOffset && uint32(cv) == lCandidate.val {
// We got a long match. Use that.
break
}
t = sCandidate.offset - e.cur
if s-t < maxMatchOffset && uint32(cv) == sCandidate.val {
// Found a 4 match...
lCandidate = e.bTable[hash7(next, tableBits)]
// If the next long is a candidate, check if we should use that instead...
lOff := nextS - (lCandidate.offset - e.cur)
if lOff < maxMatchOffset && lCandidate.val == uint32(next) {
l1, l2 := matchLen(src[s+4:], src[t+4:]), matchLen(src[nextS+4:], src[nextS-lOff+4:])
if l2 > l1 {
s = nextS
t = lCandidate.offset - e.cur
}
}
break
}
cv = next
}
// A 4-byte match has been found. We'll later see if more than 4 bytes
// match. But, prior to the match, src[nextEmit:s] are unmatched. Emit
// them as literal bytes.
// Extend the 4-byte match as long as possible.
l := e.matchlenLong(s+4, t+4, src) + 4
// Extend backwards
for t > 0 && s > nextEmit && src[t-1] == src[s-1] {
s--
t--
l++
}
if nextEmit < s {
emitLiteral(dst, src[nextEmit:s])
}
if false {
if t >= s {
panic("s-t")
}
if (s - t) > maxMatchOffset {
panic(fmt.Sprintln("mmo", t))
}
if l < baseMatchLength {
panic("bml")
}
}
dst.AddMatchLong(l, uint32(s-t-baseMatchOffset))
s += l
nextEmit = s
if nextS >= s {
s = nextS + 1
}
if s >= sLimit {
// Index first pair after match end.
if int(s+8) < len(src) {
cv := load6432(src, s)
e.table[hash4x64(cv, tableBits)] = tableEntry{offset: s + e.cur, val: uint32(cv)}
e.bTable[hash7(cv, tableBits)] = tableEntry{offset: s + e.cur, val: uint32(cv)}
}
goto emitRemainder
}
// Store every 3rd hash in-between
if true {
i := nextS
if i < s-1 {
cv := load6432(src, i)
t := tableEntry{offset: i + e.cur, val: uint32(cv)}
t2 := tableEntry{val: uint32(cv >> 8), offset: t.offset + 1}
e.bTable[hash7(cv, tableBits)] = t
e.bTable[hash7(cv>>8, tableBits)] = t2
e.table[hash4u(t2.val, tableBits)] = t2
i += 3
for ; i < s-1; i += 3 {
cv := load6432(src, i)
t := tableEntry{offset: i + e.cur, val: uint32(cv)}
t2 := tableEntry{val: uint32(cv >> 8), offset: t.offset + 1}
e.bTable[hash7(cv, tableBits)] = t
e.bTable[hash7(cv>>8, tableBits)] = t2
e.table[hash4u(t2.val, tableBits)] = t2
}
}
}
// We could immediately start working at s now, but to improve
// compression we first update the hash table at s-1 and at s.
x := load6432(src, s-1)
o := e.cur + s - 1
prevHashS := hash4x64(x, tableBits)
prevHashL := hash7(x, tableBits)
e.table[prevHashS] = tableEntry{offset: o, val: uint32(x)}
e.bTable[prevHashL] = tableEntry{offset: o, val: uint32(x)}
cv = x >> 8
}
emitRemainder:
if int(nextEmit) < len(src) {
// If nothing was added, don't encode literals.
if dst.n == 0 {
return
}
emitLiteral(dst, src[nextEmit:])
}
}

276
vendor/github.com/klauspost/compress/flate/level5.go generated vendored Normal file
View file

@ -0,0 +1,276 @@
package flate
import "fmt"
type fastEncL5 struct {
fastGen
table [tableSize]tableEntry
bTable [tableSize]tableEntryPrev
}
func (e *fastEncL5) Encode(dst *tokens, src []byte) {
const (
inputMargin = 12 - 1
minNonLiteralBlockSize = 1 + 1 + inputMargin
)
// Protect against e.cur wraparound.
for e.cur >= bufferReset {
if len(e.hist) == 0 {
for i := range e.table[:] {
e.table[i] = tableEntry{}
}
for i := range e.bTable[:] {
e.bTable[i] = tableEntryPrev{}
}
e.cur = maxMatchOffset
break
}
// Shift down everything in the table that isn't already too far away.
minOff := e.cur + int32(len(e.hist)) - maxMatchOffset
for i := range e.table[:] {
v := e.table[i].offset
if v <= minOff {
v = 0
} else {
v = v - e.cur + maxMatchOffset
}
e.table[i].offset = v
}
for i := range e.bTable[:] {
v := e.bTable[i]
if v.Cur.offset <= minOff {
v.Cur.offset = 0
v.Prev.offset = 0
} else {
v.Cur.offset = v.Cur.offset - e.cur + maxMatchOffset
if v.Prev.offset <= minOff {
v.Prev.offset = 0
} else {
v.Prev.offset = v.Prev.offset - e.cur + maxMatchOffset
}
}
e.bTable[i] = v
}
e.cur = maxMatchOffset
}
s := e.addBlock(src)
// This check isn't in the Snappy implementation, but there, the caller
// instead of the callee handles this case.
if len(src) < minNonLiteralBlockSize {
// We do not fill the token table.
// This will be picked up by caller.
dst.n = uint16(len(src))
return
}
// Override src
src = e.hist
nextEmit := s
// sLimit is when to stop looking for offset/length copies. The inputMargin
// lets us use a fast path for emitLiteral in the main loop, while we are
// looking for copies.
sLimit := int32(len(src) - inputMargin)
// nextEmit is where in src the next emitLiteral should start from.
cv := load6432(src, s)
for {
const skipLog = 6
const doEvery = 1
nextS := s
var l int32
var t int32
for {
nextHashS := hash4x64(cv, tableBits)
nextHashL := hash7(cv, tableBits)
s = nextS
nextS = s + doEvery + (s-nextEmit)>>skipLog
if nextS > sLimit {
goto emitRemainder
}
// Fetch a short+long candidate
sCandidate := e.table[nextHashS]
lCandidate := e.bTable[nextHashL]
next := load6432(src, nextS)
entry := tableEntry{offset: s + e.cur, val: uint32(cv)}
e.table[nextHashS] = entry
eLong := &e.bTable[nextHashL]
eLong.Cur, eLong.Prev = entry, eLong.Cur
nextHashS = hash4x64(next, tableBits)
nextHashL = hash7(next, tableBits)
t = lCandidate.Cur.offset - e.cur
if s-t < maxMatchOffset {
if uint32(cv) == lCandidate.Cur.val {
// Store the next match
e.table[nextHashS] = tableEntry{offset: nextS + e.cur, val: uint32(next)}
eLong := &e.bTable[nextHashL]
eLong.Cur, eLong.Prev = tableEntry{offset: nextS + e.cur, val: uint32(next)}, eLong.Cur
t2 := lCandidate.Prev.offset - e.cur
if s-t2 < maxMatchOffset && uint32(cv) == lCandidate.Prev.val {
l = e.matchlen(s+4, t+4, src) + 4
ml1 := e.matchlen(s+4, t2+4, src) + 4
if ml1 > l {
t = t2
l = ml1
break
}
}
break
}
t = lCandidate.Prev.offset - e.cur
if s-t < maxMatchOffset && uint32(cv) == lCandidate.Prev.val {
// Store the next match
e.table[nextHashS] = tableEntry{offset: nextS + e.cur, val: uint32(next)}
eLong := &e.bTable[nextHashL]
eLong.Cur, eLong.Prev = tableEntry{offset: nextS + e.cur, val: uint32(next)}, eLong.Cur
break
}
}
t = sCandidate.offset - e.cur
if s-t < maxMatchOffset && uint32(cv) == sCandidate.val {
// Found a 4 match...
l = e.matchlen(s+4, t+4, src) + 4
lCandidate = e.bTable[nextHashL]
// Store the next match
e.table[nextHashS] = tableEntry{offset: nextS + e.cur, val: uint32(next)}
eLong := &e.bTable[nextHashL]
eLong.Cur, eLong.Prev = tableEntry{offset: nextS + e.cur, val: uint32(next)}, eLong.Cur
// If the next long is a candidate, use that...
t2 := lCandidate.Cur.offset - e.cur
if nextS-t2 < maxMatchOffset {
if lCandidate.Cur.val == uint32(next) {
ml := e.matchlen(nextS+4, t2+4, src) + 4
if ml > l {
t = t2
s = nextS
l = ml
break
}
}
// If the previous long is a candidate, use that...
t2 = lCandidate.Prev.offset - e.cur
if nextS-t2 < maxMatchOffset && lCandidate.Prev.val == uint32(next) {
ml := e.matchlen(nextS+4, t2+4, src) + 4
if ml > l {
t = t2
s = nextS
l = ml
break
}
}
}
break
}
cv = next
}
// A 4-byte match has been found. We'll later see if more than 4 bytes
// match. But, prior to the match, src[nextEmit:s] are unmatched. Emit
// them as literal bytes.
// Extend the 4-byte match as long as possible.
if l == 0 {
l = e.matchlenLong(s+4, t+4, src) + 4
} else if l == maxMatchLength {
l += e.matchlenLong(s+l, t+l, src)
}
// Extend backwards
for t > 0 && s > nextEmit && src[t-1] == src[s-1] {
s--
t--
l++
}
if nextEmit < s {
emitLiteral(dst, src[nextEmit:s])
}
if false {
if t >= s {
panic(fmt.Sprintln("s-t", s, t))
}
if (s - t) > maxMatchOffset {
panic(fmt.Sprintln("mmo", s-t))
}
if l < baseMatchLength {
panic("bml")
}
}
dst.AddMatchLong(l, uint32(s-t-baseMatchOffset))
s += l
nextEmit = s
if nextS >= s {
s = nextS + 1
}
if s >= sLimit {
goto emitRemainder
}
// Store every 3rd hash in-between.
if true {
const hashEvery = 3
i := s - l + 1
if i < s-1 {
cv := load6432(src, i)
t := tableEntry{offset: i + e.cur, val: uint32(cv)}
e.table[hash4x64(cv, tableBits)] = t
eLong := &e.bTable[hash7(cv, tableBits)]
eLong.Cur, eLong.Prev = t, eLong.Cur
// Do an long at i+1
cv >>= 8
t = tableEntry{offset: t.offset + 1, val: uint32(cv)}
eLong = &e.bTable[hash7(cv, tableBits)]
eLong.Cur, eLong.Prev = t, eLong.Cur
// We only have enough bits for a short entry at i+2
cv >>= 8
t = tableEntry{offset: t.offset + 1, val: uint32(cv)}
e.table[hash4x64(cv, tableBits)] = t
// Skip one - otherwise we risk hitting 's'
i += 4
for ; i < s-1; i += hashEvery {
cv := load6432(src, i)
t := tableEntry{offset: i + e.cur, val: uint32(cv)}
t2 := tableEntry{offset: t.offset + 1, val: uint32(cv >> 8)}
eLong := &e.bTable[hash7(cv, tableBits)]
eLong.Cur, eLong.Prev = t, eLong.Cur
e.table[hash4u(t2.val, tableBits)] = t2
}
}
}
// We could immediately start working at s now, but to improve
// compression we first update the hash table at s-1 and at s.
x := load6432(src, s-1)
o := e.cur + s - 1
prevHashS := hash4x64(x, tableBits)
prevHashL := hash7(x, tableBits)
e.table[prevHashS] = tableEntry{offset: o, val: uint32(x)}
eLong := &e.bTable[prevHashL]
eLong.Cur, eLong.Prev = tableEntry{offset: o, val: uint32(x)}, eLong.Cur
cv = x >> 8
}
emitRemainder:
if int(nextEmit) < len(src) {
// If nothing was added, don't encode literals.
if dst.n == 0 {
return
}
emitLiteral(dst, src[nextEmit:])
}
}

279
vendor/github.com/klauspost/compress/flate/level6.go generated vendored Normal file
View file

@ -0,0 +1,279 @@
package flate
import "fmt"
type fastEncL6 struct {
fastGen
table [tableSize]tableEntry
bTable [tableSize]tableEntryPrev
}
func (e *fastEncL6) Encode(dst *tokens, src []byte) {
const (
inputMargin = 12 - 1
minNonLiteralBlockSize = 1 + 1 + inputMargin
)
// Protect against e.cur wraparound.
for e.cur >= bufferReset {
if len(e.hist) == 0 {
for i := range e.table[:] {
e.table[i] = tableEntry{}
}
for i := range e.bTable[:] {
e.bTable[i] = tableEntryPrev{}
}
e.cur = maxMatchOffset
break
}
// Shift down everything in the table that isn't already too far away.
minOff := e.cur + int32(len(e.hist)) - maxMatchOffset
for i := range e.table[:] {
v := e.table[i].offset
if v <= minOff {
v = 0
} else {
v = v - e.cur + maxMatchOffset
}
e.table[i].offset = v
}
for i := range e.bTable[:] {
v := e.bTable[i]
if v.Cur.offset <= minOff {
v.Cur.offset = 0
v.Prev.offset = 0
} else {
v.Cur.offset = v.Cur.offset - e.cur + maxMatchOffset
if v.Prev.offset <= minOff {
v.Prev.offset = 0
} else {
v.Prev.offset = v.Prev.offset - e.cur + maxMatchOffset
}
}
e.bTable[i] = v
}
e.cur = maxMatchOffset
}
s := e.addBlock(src)
// This check isn't in the Snappy implementation, but there, the caller
// instead of the callee handles this case.
if len(src) < minNonLiteralBlockSize {
// We do not fill the token table.
// This will be picked up by caller.
dst.n = uint16(len(src))
return
}
// Override src
src = e.hist
nextEmit := s
// sLimit is when to stop looking for offset/length copies. The inputMargin
// lets us use a fast path for emitLiteral in the main loop, while we are
// looking for copies.
sLimit := int32(len(src) - inputMargin)
// nextEmit is where in src the next emitLiteral should start from.
cv := load6432(src, s)
// Repeat MUST be > 1 and within range
repeat := int32(1)
for {
const skipLog = 7
const doEvery = 1
nextS := s
var l int32
var t int32
for {
nextHashS := hash4x64(cv, tableBits)
nextHashL := hash7(cv, tableBits)
s = nextS
nextS = s + doEvery + (s-nextEmit)>>skipLog
if nextS > sLimit {
goto emitRemainder
}
// Fetch a short+long candidate
sCandidate := e.table[nextHashS]
lCandidate := e.bTable[nextHashL]
next := load6432(src, nextS)
entry := tableEntry{offset: s + e.cur, val: uint32(cv)}
e.table[nextHashS] = entry
eLong := &e.bTable[nextHashL]
eLong.Cur, eLong.Prev = entry, eLong.Cur
// Calculate hashes of 'next'
nextHashS = hash4x64(next, tableBits)
nextHashL = hash7(next, tableBits)
t = lCandidate.Cur.offset - e.cur
if s-t < maxMatchOffset {
if uint32(cv) == lCandidate.Cur.val {
// Long candidate matches at least 4 bytes.
// Store the next match
e.table[nextHashS] = tableEntry{offset: nextS + e.cur, val: uint32(next)}
eLong := &e.bTable[nextHashL]
eLong.Cur, eLong.Prev = tableEntry{offset: nextS + e.cur, val: uint32(next)}, eLong.Cur
// Check the previous long candidate as well.
t2 := lCandidate.Prev.offset - e.cur
if s-t2 < maxMatchOffset && uint32(cv) == lCandidate.Prev.val {
l = e.matchlen(s+4, t+4, src) + 4
ml1 := e.matchlen(s+4, t2+4, src) + 4
if ml1 > l {
t = t2
l = ml1
break
}
}
break
}
// Current value did not match, but check if previous long value does.
t = lCandidate.Prev.offset - e.cur
if s-t < maxMatchOffset && uint32(cv) == lCandidate.Prev.val {
// Store the next match
e.table[nextHashS] = tableEntry{offset: nextS + e.cur, val: uint32(next)}
eLong := &e.bTable[nextHashL]
eLong.Cur, eLong.Prev = tableEntry{offset: nextS + e.cur, val: uint32(next)}, eLong.Cur
break
}
}
t = sCandidate.offset - e.cur
if s-t < maxMatchOffset && uint32(cv) == sCandidate.val {
// Found a 4 match...
l = e.matchlen(s+4, t+4, src) + 4
// Look up next long candidate (at nextS)
lCandidate = e.bTable[nextHashL]
// Store the next match
e.table[nextHashS] = tableEntry{offset: nextS + e.cur, val: uint32(next)}
eLong := &e.bTable[nextHashL]
eLong.Cur, eLong.Prev = tableEntry{offset: nextS + e.cur, val: uint32(next)}, eLong.Cur
// Check repeat at s + repOff
const repOff = 1
t2 := s - repeat + repOff
if load3232(src, t2) == uint32(cv>>(8*repOff)) {
ml := e.matchlen(s+4+repOff, t2+4, src) + 4
if ml > l {
t = t2
l = ml
s += repOff
// Not worth checking more.
break
}
}
// If the next long is a candidate, use that...
t2 = lCandidate.Cur.offset - e.cur
if nextS-t2 < maxMatchOffset {
if lCandidate.Cur.val == uint32(next) {
ml := e.matchlen(nextS+4, t2+4, src) + 4
if ml > l {
t = t2
s = nextS
l = ml
// This is ok, but check previous as well.
}
}
// If the previous long is a candidate, use that...
t2 = lCandidate.Prev.offset - e.cur
if nextS-t2 < maxMatchOffset && lCandidate.Prev.val == uint32(next) {
ml := e.matchlen(nextS+4, t2+4, src) + 4
if ml > l {
t = t2
s = nextS
l = ml
break
}
}
}
break
}
cv = next
}
// A 4-byte match has been found. We'll later see if more than 4 bytes
// match. But, prior to the match, src[nextEmit:s] are unmatched. Emit
// them as literal bytes.
// Extend the 4-byte match as long as possible.
if l == 0 {
l = e.matchlenLong(s+4, t+4, src) + 4
} else if l == maxMatchLength {
l += e.matchlenLong(s+l, t+l, src)
}
// Extend backwards
for t > 0 && s > nextEmit && src[t-1] == src[s-1] {
s--
t--
l++
}
if nextEmit < s {
emitLiteral(dst, src[nextEmit:s])
}
if false {
if t >= s {
panic(fmt.Sprintln("s-t", s, t))
}
if (s - t) > maxMatchOffset {
panic(fmt.Sprintln("mmo", s-t))
}
if l < baseMatchLength {
panic("bml")
}
}
dst.AddMatchLong(l, uint32(s-t-baseMatchOffset))
repeat = s - t
s += l
nextEmit = s
if nextS >= s {
s = nextS + 1
}
if s >= sLimit {
// Index after match end.
for i := nextS + 1; i < int32(len(src))-8; i += 2 {
cv := load6432(src, i)
e.table[hash4x64(cv, tableBits)] = tableEntry{offset: i + e.cur, val: uint32(cv)}
eLong := &e.bTable[hash7(cv, tableBits)]
eLong.Cur, eLong.Prev = tableEntry{offset: i + e.cur, val: uint32(cv)}, eLong.Cur
}
goto emitRemainder
}
// Store every long hash in-between and every second short.
if true {
for i := nextS + 1; i < s-1; i += 2 {
cv := load6432(src, i)
t := tableEntry{offset: i + e.cur, val: uint32(cv)}
t2 := tableEntry{offset: t.offset + 1, val: uint32(cv >> 8)}
eLong := &e.bTable[hash7(cv, tableBits)]
eLong2 := &e.bTable[hash7(cv>>8, tableBits)]
e.table[hash4x64(cv, tableBits)] = t
eLong.Cur, eLong.Prev = t, eLong.Cur
eLong2.Cur, eLong2.Prev = t2, eLong2.Cur
}
}
// We could immediately start working at s now, but to improve
// compression we first update the hash table at s-1 and at s.
cv = load6432(src, s)
}
emitRemainder:
if int(nextEmit) < len(src) {
// If nothing was added, don't encode literals.
if dst.n == 0 {
return
}
emitLiteral(dst, src[nextEmit:])
}
}

48
vendor/github.com/klauspost/compress/flate/reverse_bits.go generated vendored
View file

@ -1,48 +0,0 @@
// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package flate
var reverseByte = [256]byte{
0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0,
0x10, 0x90, 0x50, 0xd0, 0x30, 0xb0, 0x70, 0xf0,
0x08, 0x88, 0x48, 0xc8, 0x28, 0xa8, 0x68, 0xe8,
0x18, 0x98, 0x58, 0xd8, 0x38, 0xb8, 0x78, 0xf8,
0x04, 0x84, 0x44, 0xc4, 0x24, 0xa4, 0x64, 0xe4,
0x14, 0x94, 0x54, 0xd4, 0x34, 0xb4, 0x74, 0xf4,
0x0c, 0x8c, 0x4c, 0xcc, 0x2c, 0xac, 0x6c, 0xec,
0x1c, 0x9c, 0x5c, 0xdc, 0x3c, 0xbc, 0x7c, 0xfc,
0x02, 0x82, 0x42, 0xc2, 0x22, 0xa2, 0x62, 0xe2,
0x12, 0x92, 0x52, 0xd2, 0x32, 0xb2, 0x72, 0xf2,
0x0a, 0x8a, 0x4a, 0xca, 0x2a, 0xaa, 0x6a, 0xea,
0x1a, 0x9a, 0x5a, 0xda, 0x3a, 0xba, 0x7a, 0xfa,
0x06, 0x86, 0x46, 0xc6, 0x26, 0xa6, 0x66, 0xe6,
0x16, 0x96, 0x56, 0xd6, 0x36, 0xb6, 0x76, 0xf6,
0x0e, 0x8e, 0x4e, 0xce, 0x2e, 0xae, 0x6e, 0xee,
0x1e, 0x9e, 0x5e, 0xde, 0x3e, 0xbe, 0x7e, 0xfe,
0x01, 0x81, 0x41, 0xc1, 0x21, 0xa1, 0x61, 0xe1,
0x11, 0x91, 0x51, 0xd1, 0x31, 0xb1, 0x71, 0xf1,
0x09, 0x89, 0x49, 0xc9, 0x29, 0xa9, 0x69, 0xe9,
0x19, 0x99, 0x59, 0xd9, 0x39, 0xb9, 0x79, 0xf9,
0x05, 0x85, 0x45, 0xc5, 0x25, 0xa5, 0x65, 0xe5,
0x15, 0x95, 0x55, 0xd5, 0x35, 0xb5, 0x75, 0xf5,
0x0d, 0x8d, 0x4d, 0xcd, 0x2d, 0xad, 0x6d, 0xed,
0x1d, 0x9d, 0x5d, 0xdd, 0x3d, 0xbd, 0x7d, 0xfd,
0x03, 0x83, 0x43, 0xc3, 0x23, 0xa3, 0x63, 0xe3,
0x13, 0x93, 0x53, 0xd3, 0x33, 0xb3, 0x73, 0xf3,
0x0b, 0x8b, 0x4b, 0xcb, 0x2b, 0xab, 0x6b, 0xeb,
0x1b, 0x9b, 0x5b, 0xdb, 0x3b, 0xbb, 0x7b, 0xfb,
0x07, 0x87, 0x47, 0xc7, 0x27, 0xa7, 0x67, 0xe7,
0x17, 0x97, 0x57, 0xd7, 0x37, 0xb7, 0x77, 0xf7,
0x0f, 0x8f, 0x4f, 0xcf, 0x2f, 0xaf, 0x6f, 0xef,
0x1f, 0x9f, 0x5f, 0xdf, 0x3f, 0xbf, 0x7f, 0xff,
}
func reverseUint16(v uint16) uint16 {
return uint16(reverseByte[v>>8]) | uint16(reverseByte[v&0xFF])<<8
}
func reverseBits(number uint16, bitLength byte) uint16 {
return reverseUint16(number << uint8(16-bitLength))
}

856
vendor/github.com/klauspost/compress/flate/snappy.go generated vendored
View file

@ -1,856 +0,0 @@
// Copyright 2011 The Snappy-Go Authors. All rights reserved.
// Modified for deflate by Klaus Post (c) 2015.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package flate
// emitLiteral writes a literal chunk and returns the number of bytes written.
func emitLiteral(dst *tokens, lit []byte) {
ol := int(dst.n)
for i, v := range lit {
dst.tokens[(i+ol)&maxStoreBlockSize] = token(v)
}
dst.n += uint16(len(lit))
}
// emitCopy writes a copy chunk and returns the number of bytes written.
func emitCopy(dst *tokens, offset, length int) {
dst.tokens[dst.n] = matchToken(uint32(length-3), uint32(offset-minOffsetSize))
dst.n++
}
type snappyEnc interface {
Encode(dst *tokens, src []byte)
Reset()
}
func newSnappy(level int) snappyEnc {
switch level {
case 1:
return &snappyL1{}
case 2:
return &snappyL2{snappyGen: snappyGen{cur: maxStoreBlockSize, prev: make([]byte, 0, maxStoreBlockSize)}}
case 3:
return &snappyL3{snappyGen: snappyGen{cur: maxStoreBlockSize, prev: make([]byte, 0, maxStoreBlockSize)}}
case 4:
return &snappyL4{snappyL3{snappyGen: snappyGen{cur: maxStoreBlockSize, prev: make([]byte, 0, maxStoreBlockSize)}}}
default:
panic("invalid level specified")
}
}
const (
tableBits = 14 // Bits used in the table
tableSize = 1 << tableBits // Size of the table
tableMask = tableSize - 1 // Mask for table indices. Redundant, but can eliminate bounds checks.
tableShift = 32 - tableBits // Right-shift to get the tableBits most significant bits of a uint32.
baseMatchOffset = 1 // The smallest match offset
baseMatchLength = 3 // The smallest match length per the RFC section 3.2.5
maxMatchOffset = 1 << 15 // The largest match offset
)
func load32(b []byte, i int) uint32 {
b = b[i : i+4 : len(b)] // Help the compiler eliminate bounds checks on the next line.
return uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24
}
func load64(b []byte, i int) uint64 {
b = b[i : i+8 : len(b)] // Help the compiler eliminate bounds checks on the next line.
return uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 |
uint64(b[4])<<32 | uint64(b[5])<<40 | uint64(b[6])<<48 | uint64(b[7])<<56
}
func hash(u uint32) uint32 {
return (u * 0x1e35a7bd) >> tableShift
}
// snappyL1 encapsulates level 1 compression
type snappyL1 struct{}
func (e *snappyL1) Reset() {}
func (e *snappyL1) Encode(dst *tokens, src []byte) {
const (
inputMargin = 16 - 1
minNonLiteralBlockSize = 1 + 1 + inputMargin
)
// This check isn't in the Snappy implementation, but there, the caller
// instead of the callee handles this case.
if len(src) < minNonLiteralBlockSize {
// We do not fill the token table.
// This will be picked up by caller.
dst.n = uint16(len(src))
return
}
// Initialize the hash table.
//
// The table element type is uint16, as s < sLimit and sLimit < len(src)
// and len(src) <= maxStoreBlockSize and maxStoreBlockSize == 65535.
var table [tableSize]uint16
// sLimit is when to stop looking for offset/length copies. The inputMargin
// lets us use a fast path for emitLiteral in the main loop, while we are
// looking for copies.
sLimit := len(src) - inputMargin
// nextEmit is where in src the next emitLiteral should start from.
nextEmit := 0
// The encoded form must start with a literal, as there are no previous
// bytes to copy, so we start looking for hash matches at s == 1.
s := 1
nextHash := hash(load32(src, s))
for {
// Copied from the C++ snappy implementation:
//
// Heuristic match skipping: If 32 bytes are scanned with no matches
// found, start looking only at every other byte. If 32 more bytes are
// scanned (or skipped), look at every third byte, etc.. When a match
// is found, immediately go back to looking at every byte. This is a
// small loss (~5% performance, ~0.1% density) for compressible data
// due to more bookkeeping, but for non-compressible data (such as
// JPEG) it's a huge win since the compressor quickly "realizes" the
// data is incompressible and doesn't bother looking for matches
// everywhere.
//
// The "skip" variable keeps track of how many bytes there are since
// the last match; dividing it by 32 (ie. right-shifting by five) gives
// the number of bytes to move ahead for each iteration.
skip := 32
nextS := s
candidate := 0
for {
s = nextS
bytesBetweenHashLookups := skip >> 5
nextS = s + bytesBetweenHashLookups
skip += bytesBetweenHashLookups
if nextS > sLimit {
goto emitRemainder
}
candidate = int(table[nextHash&tableMask])
table[nextHash&tableMask] = uint16(s)
nextHash = hash(load32(src, nextS))
// TODO: < should be <=, and add a test for that.
if s-candidate < maxMatchOffset && load32(src, s) == load32(src, candidate) {
break
}
}
// A 4-byte match has been found. We'll later see if more than 4 bytes
// match. But, prior to the match, src[nextEmit:s] are unmatched. Emit
// them as literal bytes.
emitLiteral(dst, src[nextEmit:s])
// Call emitCopy, and then see if another emitCopy could be our next
// move. Repeat until we find no match for the input immediately after
// what was consumed by the last emitCopy call.
//
// If we exit this loop normally then we need to call emitLiteral next,
// though we don't yet know how big the literal will be. We handle that
// by proceeding to the next iteration of the main loop. We also can
// exit this loop via goto if we get close to exhausting the input.
for {
// Invariant: we have a 4-byte match at s, and no need to emit any
// literal bytes prior to s.
base := s
// Extend the 4-byte match as long as possible.
//
// This is an inlined version of Snappy's:
// s = extendMatch(src, candidate+4, s+4)
s += 4
s1 := base + maxMatchLength
if s1 > len(src) {
s1 = len(src)
}
a := src[s:s1]
b := src[candidate+4:]
b = b[:len(a)]
l := len(a)
for i := range a {
if a[i] != b[i] {
l = i
break
}
}
s += l
// matchToken is flate's equivalent of Snappy's emitCopy.
dst.tokens[dst.n] = matchToken(uint32(s-base-baseMatchLength), uint32(base-candidate-baseMatchOffset))
dst.n++
nextEmit = s
if s >= sLimit {
goto emitRemainder
}
// We could immediately start working at s now, but to improve
// compression we first update the hash table at s-1 and at s. If
// another emitCopy is not our next move, also calculate nextHash
// at s+1. At least on GOARCH=amd64, these three hash calculations
// are faster as one load64 call (with some shifts) instead of
// three load32 calls.
x := load64(src, s-1)
prevHash := hash(uint32(x >> 0))
table[prevHash&tableMask] = uint16(s - 1)
currHash := hash(uint32(x >> 8))
candidate = int(table[currHash&tableMask])
table[currHash&tableMask] = uint16(s)
// TODO: >= should be >, and add a test for that.
if s-candidate >= maxMatchOffset || uint32(x>>8) != load32(src, candidate) {
nextHash = hash(uint32(x >> 16))
s++
break
}
}
}
emitRemainder:
if nextEmit < len(src) {
emitLiteral(dst, src[nextEmit:])
}
}
type tableEntry struct {
val uint32
offset int32
}
func load3232(b []byte, i int32) uint32 {
b = b[i : i+4 : len(b)] // Help the compiler eliminate bounds checks on the next line.
return uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24
}
func load6432(b []byte, i int32) uint64 {
b = b[i : i+8 : len(b)] // Help the compiler eliminate bounds checks on the next line.
return uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 |
uint64(b[4])<<32 | uint64(b[5])<<40 | uint64(b[6])<<48 | uint64(b[7])<<56
}
// snappyGen maintains the table for matches,
// and the previous byte block for level 2.
// This is the generic implementation.
type snappyGen struct {
prev []byte
cur int32
}
// snappyGen maintains the table for matches,
// and the previous byte block for level 2.
// This is the generic implementation.
type snappyL2 struct {
snappyGen
table [tableSize]tableEntry
}
// EncodeL2 uses a similar algorithm to level 1, but is capable
// of matching across blocks giving better compression at a small slowdown.
func (e *snappyL2) Encode(dst *tokens, src []byte) {
const (
inputMargin = 16 - 1
minNonLiteralBlockSize = 1 + 1 + inputMargin
)
// Ensure that e.cur doesn't wrap, mainly an issue on 32 bits.
if e.cur > 1<<30 {
for i := range e.table {
e.table[i] = tableEntry{}
}
e.cur = maxStoreBlockSize
}
// This check isn't in the Snappy implementation, but there, the caller
// instead of the callee handles this case.
if len(src) < minNonLiteralBlockSize {
// We do not fill the token table.
// This will be picked up by caller.
dst.n = uint16(len(src))
e.cur += maxStoreBlockSize
e.prev = e.prev[:0]
return
}
// sLimit is when to stop looking for offset/length copies. The inputMargin
// lets us use a fast path for emitLiteral in the main loop, while we are
// looking for copies.
sLimit := int32(len(src) - inputMargin)
// nextEmit is where in src the next emitLiteral should start from.
nextEmit := int32(0)
s := int32(0)
cv := load3232(src, s)
nextHash := hash(cv)
for {
// Copied from the C++ snappy implementation:
//
// Heuristic match skipping: If 32 bytes are scanned with no matches
// found, start looking only at every other byte. If 32 more bytes are
// scanned (or skipped), look at every third byte, etc.. When a match
// is found, immediately go back to looking at every byte. This is a
// small loss (~5% performance, ~0.1% density) for compressible data
// due to more bookkeeping, but for non-compressible data (such as
// JPEG) it's a huge win since the compressor quickly "realizes" the
// data is incompressible and doesn't bother looking for matches
// everywhere.
//
// The "skip" variable keeps track of how many bytes there are since
// the last match; dividing it by 32 (ie. right-shifting by five) gives
// the number of bytes to move ahead for each iteration.
skip := int32(32)
nextS := s
var candidate tableEntry
for {
s = nextS
bytesBetweenHashLookups := skip >> 5
nextS = s + bytesBetweenHashLookups
skip += bytesBetweenHashLookups
if nextS > sLimit {
goto emitRemainder
}
candidate = e.table[nextHash&tableMask]
now := load3232(src, nextS)
e.table[nextHash&tableMask] = tableEntry{offset: s + e.cur, val: cv}
nextHash = hash(now)
offset := s - (candidate.offset - e.cur)
if offset >= maxMatchOffset || cv != candidate.val {
// Out of range or not matched.
cv = now
continue
}
break
}
// A 4-byte match has been found. We'll later see if more than 4 bytes
// match. But, prior to the match, src[nextEmit:s] are unmatched. Emit
// them as literal bytes.
emitLiteral(dst, src[nextEmit:s])
// Call emitCopy, and then see if another emitCopy could be our next
// move. Repeat until we find no match for the input immediately after
// what was consumed by the last emitCopy call.
//
// If we exit this loop normally then we need to call emitLiteral next,
// though we don't yet know how big the literal will be. We handle that
// by proceeding to the next iteration of the main loop. We also can
// exit this loop via goto if we get close to exhausting the input.
for {
// Invariant: we have a 4-byte match at s, and no need to emit any
// literal bytes prior to s.
// Extend the 4-byte match as long as possible.
//
s += 4
t := candidate.offset - e.cur + 4
l := e.matchlen(s, t, src)
// matchToken is flate's equivalent of Snappy's emitCopy. (length,offset)
dst.tokens[dst.n] = matchToken(uint32(l+4-baseMatchLength), uint32(s-t-baseMatchOffset))
dst.n++
s += l
nextEmit = s
if s >= sLimit {
goto emitRemainder
}
// We could immediately start working at s now, but to improve
// compression we first update the hash table at s-1 and at s. If
// another emitCopy is not our next move, also calculate nextHash
// at s+1. At least on GOARCH=amd64, these three hash calculations
// are faster as one load64 call (with some shifts) instead of
// three load32 calls.
x := load6432(src, s-1)
prevHash := hash(uint32(x))
e.table[prevHash&tableMask] = tableEntry{offset: e.cur + s - 1, val: uint32(x)}
x >>= 8
currHash := hash(uint32(x))
candidate = e.table[currHash&tableMask]
e.table[currHash&tableMask] = tableEntry{offset: e.cur + s, val: uint32(x)}
offset := s - (candidate.offset - e.cur)
if offset >= maxMatchOffset || uint32(x) != candidate.val {
cv = uint32(x >> 8)
nextHash = hash(cv)
s++
break
}
}
}
emitRemainder:
if int(nextEmit) < len(src) {
emitLiteral(dst, src[nextEmit:])
}
e.cur += int32(len(src))
e.prev = e.prev[:len(src)]
copy(e.prev, src)
}
type tableEntryPrev struct {
Cur tableEntry
Prev tableEntry
}
// snappyL3
type snappyL3 struct {
snappyGen
table [tableSize]tableEntryPrev
}
// Encode uses a similar algorithm to level 2, will check up to two candidates.
func (e *snappyL3) Encode(dst *tokens, src []byte) {
const (
inputMargin = 16 - 1
minNonLiteralBlockSize = 1 + 1 + inputMargin
)
// Ensure that e.cur doesn't wrap, mainly an issue on 32 bits.
if e.cur > 1<<30 {
for i := range e.table {
e.table[i] = tableEntryPrev{}
}
e.cur = maxStoreBlockSize
}
// This check isn't in the Snappy implementation, but there, the caller
// instead of the callee handles this case.
if len(src) < minNonLiteralBlockSize {
// We do not fill the token table.
// This will be picked up by caller.
dst.n = uint16(len(src))
e.cur += maxStoreBlockSize
e.prev = e.prev[:0]
return
}
// sLimit is when to stop looking for offset/length copies. The inputMargin
// lets us use a fast path for emitLiteral in the main loop, while we are
// looking for copies.
sLimit := int32(len(src) - inputMargin)
// nextEmit is where in src the next emitLiteral should start from.
nextEmit := int32(0)
s := int32(0)
cv := load3232(src, s)
nextHash := hash(cv)
for {
// Copied from the C++ snappy implementation:
//
// Heuristic match skipping: If 32 bytes are scanned with no matches
// found, start looking only at every other byte. If 32 more bytes are
// scanned (or skipped), look at every third byte, etc.. When a match
// is found, immediately go back to looking at every byte. This is a
// small loss (~5% performance, ~0.1% density) for compressible data
// due to more bookkeeping, but for non-compressible data (such as
// JPEG) it's a huge win since the compressor quickly "realizes" the
// data is incompressible and doesn't bother looking for matches
// everywhere.
//
// The "skip" variable keeps track of how many bytes there are since
// the last match; dividing it by 32 (ie. right-shifting by five) gives
// the number of bytes to move ahead for each iteration.
skip := int32(32)
nextS := s
var candidate tableEntry
for {
s = nextS
bytesBetweenHashLookups := skip >> 5
nextS = s + bytesBetweenHashLookups
skip += bytesBetweenHashLookups
if nextS > sLimit {
goto emitRemainder
}
candidates := e.table[nextHash&tableMask]
now := load3232(src, nextS)
e.table[nextHash&tableMask] = tableEntryPrev{Prev: candidates.Cur, Cur: tableEntry{offset: s + e.cur, val: cv}}
nextHash = hash(now)
// Check both candidates
candidate = candidates.Cur
if cv == candidate.val {
offset := s - (candidate.offset - e.cur)
if offset < maxMatchOffset {
break
}
} else {
// We only check if value mismatches.
// Offset will always be invalid in other cases.
candidate = candidates.Prev
if cv == candidate.val {
offset := s - (candidate.offset - e.cur)
if offset < maxMatchOffset {
break
}
}
}
cv = now
}
// A 4-byte match has been found. We'll later see if more than 4 bytes
// match. But, prior to the match, src[nextEmit:s] are unmatched. Emit
// them as literal bytes.
emitLiteral(dst, src[nextEmit:s])
// Call emitCopy, and then see if another emitCopy could be our next
// move. Repeat until we find no match for the input immediately after
// what was consumed by the last emitCopy call.
//
// If we exit this loop normally then we need to call emitLiteral next,
// though we don't yet know how big the literal will be. We handle that
// by proceeding to the next iteration of the main loop. We also can
// exit this loop via goto if we get close to exhausting the input.
for {
// Invariant: we have a 4-byte match at s, and no need to emit any
// literal bytes prior to s.
// Extend the 4-byte match as long as possible.
//
s += 4
t := candidate.offset - e.cur + 4
l := e.matchlen(s, t, src)
// matchToken is flate's equivalent of Snappy's emitCopy. (length,offset)
dst.tokens[dst.n] = matchToken(uint32(l+4-baseMatchLength), uint32(s-t-baseMatchOffset))
dst.n++
s += l
nextEmit = s
if s >= sLimit {
goto emitRemainder
}
// We could immediately start working at s now, but to improve
// compression we first update the hash table at s-2, s-1 and at s. If
// another emitCopy is not our next move, also calculate nextHash
// at s+1. At least on GOARCH=amd64, these three hash calculations
// are faster as one load64 call (with some shifts) instead of
// three load32 calls.
x := load6432(src, s-2)
prevHash := hash(uint32(x))
e.table[prevHash&tableMask] = tableEntryPrev{
Prev: e.table[prevHash&tableMask].Cur,
Cur: tableEntry{offset: e.cur + s - 2, val: uint32(x)},
}
x >>= 8
prevHash = hash(uint32(x))
e.table[prevHash&tableMask] = tableEntryPrev{
Prev: e.table[prevHash&tableMask].Cur,
Cur: tableEntry{offset: e.cur + s - 1, val: uint32(x)},
}
x >>= 8
currHash := hash(uint32(x))
candidates := e.table[currHash&tableMask]
cv = uint32(x)
e.table[currHash&tableMask] = tableEntryPrev{
Prev: candidates.Cur,
Cur: tableEntry{offset: s + e.cur, val: cv},
}
// Check both candidates
candidate = candidates.Cur
if cv == candidate.val {
offset := s - (candidate.offset - e.cur)
if offset < maxMatchOffset {
continue
}
} else {
// We only check if value mismatches.
// Offset will always be invalid in other cases.
candidate = candidates.Prev
if cv == candidate.val {
offset := s - (candidate.offset - e.cur)
if offset < maxMatchOffset {
continue
}
}
}
cv = uint32(x >> 8)
nextHash = hash(cv)
s++
break
}
}
emitRemainder:
if int(nextEmit) < len(src) {
emitLiteral(dst, src[nextEmit:])
}
e.cur += int32(len(src))
e.prev = e.prev[:len(src)]
copy(e.prev, src)
}
// snappyL4
type snappyL4 struct {
snappyL3
}
// Encode uses a similar algorithm to level 3,
// but will check up to two candidates if first isn't long enough.
func (e *snappyL4) Encode(dst *tokens, src []byte) {
const (
inputMargin = 16 - 1
minNonLiteralBlockSize = 1 + 1 + inputMargin
matchLenGood = 12
)
// Ensure that e.cur doesn't wrap, mainly an issue on 32 bits.
if e.cur > 1<<30 {
for i := range e.table {
e.table[i] = tableEntryPrev{}
}
e.cur = maxStoreBlockSize
}
// This check isn't in the Snappy implementation, but there, the caller
// instead of the callee handles this case.
if len(src) < minNonLiteralBlockSize {
// We do not fill the token table.
// This will be picked up by caller.
dst.n = uint16(len(src))
e.cur += maxStoreBlockSize
e.prev = e.prev[:0]
return
}
// sLimit is when to stop looking for offset/length copies. The inputMargin
// lets us use a fast path for emitLiteral in the main loop, while we are
// looking for copies.
sLimit := int32(len(src) - inputMargin)
// nextEmit is where in src the next emitLiteral should start from.
nextEmit := int32(0)
s := int32(0)
cv := load3232(src, s)
nextHash := hash(cv)
for {
// Copied from the C++ snappy implementation:
//
// Heuristic match skipping: If 32 bytes are scanned with no matches
// found, start looking only at every other byte. If 32 more bytes are
// scanned (or skipped), look at every third byte, etc.. When a match
// is found, immediately go back to looking at every byte. This is a
// small loss (~5% performance, ~0.1% density) for compressible data
// due to more bookkeeping, but for non-compressible data (such as
// JPEG) it's a huge win since the compressor quickly "realizes" the
// data is incompressible and doesn't bother looking for matches
// everywhere.
//
// The "skip" variable keeps track of how many bytes there are since
// the last match; dividing it by 32 (ie. right-shifting by five) gives
// the number of bytes to move ahead for each iteration.
skip := int32(32)
nextS := s
var candidate tableEntry
var candidateAlt tableEntry
for {
s = nextS
bytesBetweenHashLookups := skip >> 5
nextS = s + bytesBetweenHashLookups
skip += bytesBetweenHashLookups
if nextS > sLimit {
goto emitRemainder
}
candidates := e.table[nextHash&tableMask]
now := load3232(src, nextS)
e.table[nextHash&tableMask] = tableEntryPrev{Prev: candidates.Cur, Cur: tableEntry{offset: s + e.cur, val: cv}}
nextHash = hash(now)
// Check both candidates
candidate = candidates.Cur
if cv == candidate.val {
offset := s - (candidate.offset - e.cur)
if offset < maxMatchOffset {
offset = s - (candidates.Prev.offset - e.cur)
if cv == candidates.Prev.val && offset < maxMatchOffset {
candidateAlt = candidates.Prev
}
break
}
} else {
// We only check if value mismatches.
// Offset will always be invalid in other cases.
candidate = candidates.Prev
if cv == candidate.val {
offset := s - (candidate.offset - e.cur)
if offset < maxMatchOffset {
break
}
}
}
cv = now
}
// A 4-byte match has been found. We'll later see if more than 4 bytes
// match. But, prior to the match, src[nextEmit:s] are unmatched. Emit
// them as literal bytes.
emitLiteral(dst, src[nextEmit:s])
// Call emitCopy, and then see if another emitCopy could be our next
// move. Repeat until we find no match for the input immediately after
// what was consumed by the last emitCopy call.
//
// If we exit this loop normally then we need to call emitLiteral next,
// though we don't yet know how big the literal will be. We handle that
// by proceeding to the next iteration of the main loop. We also can
// exit this loop via goto if we get close to exhausting the input.
for {
// Invariant: we have a 4-byte match at s, and no need to emit any
// literal bytes prior to s.
// Extend the 4-byte match as long as possible.
//
s += 4
t := candidate.offset - e.cur + 4
l := e.matchlen(s, t, src)
// Try alternative candidate if match length < matchLenGood.
if l < matchLenGood-4 && candidateAlt.offset != 0 {
t2 := candidateAlt.offset - e.cur + 4
l2 := e.matchlen(s, t2, src)
if l2 > l {
l = l2
t = t2
}
}
// matchToken is flate's equivalent of Snappy's emitCopy. (length,offset)
dst.tokens[dst.n] = matchToken(uint32(l+4-baseMatchLength), uint32(s-t-baseMatchOffset))
dst.n++
s += l
nextEmit = s
if s >= sLimit {
goto emitRemainder
}
// We could immediately start working at s now, but to improve
// compression we first update the hash table at s-2, s-1 and at s. If
// another emitCopy is not our next move, also calculate nextHash
// at s+1. At least on GOARCH=amd64, these three hash calculations
// are faster as one load64 call (with some shifts) instead of
// three load32 calls.
x := load6432(src, s-2)
prevHash := hash(uint32(x))
e.table[prevHash&tableMask] = tableEntryPrev{
Prev: e.table[prevHash&tableMask].Cur,
Cur: tableEntry{offset: e.cur + s - 2, val: uint32(x)},
}
x >>= 8
prevHash = hash(uint32(x))
e.table[prevHash&tableMask] = tableEntryPrev{
Prev: e.table[prevHash&tableMask].Cur,
Cur: tableEntry{offset: e.cur + s - 1, val: uint32(x)},
}
x >>= 8
currHash := hash(uint32(x))
candidates := e.table[currHash&tableMask]
cv = uint32(x)
e.table[currHash&tableMask] = tableEntryPrev{
Prev: candidates.Cur,
Cur: tableEntry{offset: s + e.cur, val: cv},
}
// Check both candidates
candidate = candidates.Cur
candidateAlt = tableEntry{}
if cv == candidate.val {
offset := s - (candidate.offset - e.cur)
if offset < maxMatchOffset {
offset = s - (candidates.Prev.offset - e.cur)
if cv == candidates.Prev.val && offset < maxMatchOffset {
candidateAlt = candidates.Prev
}
continue
}
} else {
// We only check if value mismatches.
// Offset will always be invalid in other cases.
candidate = candidates.Prev
if cv == candidate.val {
offset := s - (candidate.offset - e.cur)
if offset < maxMatchOffset {
continue
}
}
}
cv = uint32(x >> 8)
nextHash = hash(cv)
s++
break
}
}
emitRemainder:
if int(nextEmit) < len(src) {
emitLiteral(dst, src[nextEmit:])
}
e.cur += int32(len(src))
e.prev = e.prev[:len(src)]
copy(e.prev, src)
}
func (e *snappyGen) matchlen(s, t int32, src []byte) int32 {
s1 := int(s) + maxMatchLength - 4
if s1 > len(src) {
s1 = len(src)
}
// If we are inside the current block
if t >= 0 {
b := src[t:]
a := src[s:s1]
b = b[:len(a)]
// Extend the match to be as long as possible.
for i := range a {
if a[i] != b[i] {
return int32(i)
}
}
return int32(len(a))
}
// We found a match in the previous block.
tp := int32(len(e.prev)) + t
if tp < 0 {
return 0
}
// Extend the match to be as long as possible.
a := src[s:s1]
b := e.prev[tp:]
if len(b) > len(a) {
b = b[:len(a)]
}
a = a[:len(b)]
for i := range b {
if a[i] != b[i] {
return int32(i)
}
}
n := int32(len(b))
a = src[s+n : s1]
b = src[:len(a)]
for i := range a {
if a[i] != b[i] {
return int32(i) + n
}
}
return int32(len(a)) + n
}
// Reset the encoding table.
func (e *snappyGen) Reset() {
e.prev = e.prev[:0]
e.cur += maxMatchOffset + 1
}

252
vendor/github.com/klauspost/compress/flate/stateless.go generated vendored Normal file
View file

@ -0,0 +1,252 @@
package flate
import (
"io"
"math"
)
const (
maxStatelessBlock = math.MaxInt16
slTableBits = 13
slTableSize = 1 << slTableBits
slTableShift = 32 - slTableBits
)
type statelessWriter struct {
dst io.Writer
closed bool
}
func (s *statelessWriter) Close() error {
if s.closed {
return nil
}
s.closed = true
// Emit EOF block
return StatelessDeflate(s.dst, nil, true)
}
func (s *statelessWriter) Write(p []byte) (n int, err error) {
err = StatelessDeflate(s.dst, p, false)
if err != nil {
return 0, err
}
return len(p), nil
}
func (s *statelessWriter) Reset(w io.Writer) {
s.dst = w
s.closed = false
}
// NewStatelessWriter will do compression but without maintaining any state
// between Write calls.
// There will be no memory kept between Write calls,
// but compression and speed will be suboptimal.
// Because of this, the size of actual Write calls will affect output size.
func NewStatelessWriter(dst io.Writer) io.WriteCloser {
return &statelessWriter{dst: dst}
}
// StatelessDeflate allows to compress directly to a Writer without retaining state.
// When returning everything will be flushed.
func StatelessDeflate(out io.Writer, in []byte, eof bool) error {
var dst tokens
bw := newHuffmanBitWriter(out)
if eof && len(in) == 0 {
// Just write an EOF block.
// Could be faster...
bw.writeStoredHeader(0, true)
bw.flush()
return bw.err
}
for len(in) > 0 {
todo := in
if len(todo) > maxStatelessBlock {
todo = todo[:maxStatelessBlock]
}
in = in[len(todo):]
// Compress
statelessEnc(&dst, todo)
isEof := eof && len(in) == 0
if dst.n == 0 {
bw.writeStoredHeader(len(todo), isEof)
if bw.err != nil {
return bw.err
}
bw.writeBytes(todo)
} else if int(dst.n) > len(todo)-len(todo)>>4 {
// If we removed less than 1/16th, huffman compress the block.
bw.writeBlockHuff(isEof, todo, false)
} else {
bw.writeBlockDynamic(&dst, isEof, todo, false)
}
if bw.err != nil {
return bw.err
}
dst.Reset()
}
if !eof {
// Align.
bw.writeStoredHeader(0, false)
}
bw.flush()
return bw.err
}
func hashSL(u uint32) uint32 {
return (u * 0x1e35a7bd) >> slTableShift
}
func load3216(b []byte, i int16) uint32 {
// Help the compiler eliminate bounds checks on the read so it can be done in a single read.
b = b[i:]
b = b[:4]
return uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24
}
func load6416(b []byte, i int16) uint64 {
// Help the compiler eliminate bounds checks on the read so it can be done in a single read.
b = b[i:]
b = b[:8]
return uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 |
uint64(b[4])<<32 | uint64(b[5])<<40 | uint64(b[6])<<48 | uint64(b[7])<<56
}
func statelessEnc(dst *tokens, src []byte) {
const (
inputMargin = 12 - 1
minNonLiteralBlockSize = 1 + 1 + inputMargin
)
type tableEntry struct {
offset int16
}
var table [slTableSize]tableEntry
// This check isn't in the Snappy implementation, but there, the caller
// instead of the callee handles this case.
if len(src) < minNonLiteralBlockSize {
// We do not fill the token table.
// This will be picked up by caller.
dst.n = uint16(len(src))
return
}
s := int16(1)
nextEmit := int16(0)
// sLimit is when to stop looking for offset/length copies. The inputMargin
// lets us use a fast path for emitLiteral in the main loop, while we are
// looking for copies.
sLimit := int16(len(src) - inputMargin)
// nextEmit is where in src the next emitLiteral should start from.
cv := load3216(src, s)
for {
const skipLog = 5
const doEvery = 2
nextS := s
var candidate tableEntry
for {
nextHash := hashSL(cv)
candidate = table[nextHash]
nextS = s + doEvery + (s-nextEmit)>>skipLog
if nextS > sLimit || nextS <= 0 {
goto emitRemainder
}
now := load6416(src, nextS)
table[nextHash] = tableEntry{offset: s}
nextHash = hashSL(uint32(now))
if cv == load3216(src, candidate.offset) {
table[nextHash] = tableEntry{offset: nextS}
break
}
// Do one right away...
cv = uint32(now)
s = nextS
nextS++
candidate = table[nextHash]
now >>= 8
table[nextHash] = tableEntry{offset: s}
if cv == load3216(src, candidate.offset) {
table[nextHash] = tableEntry{offset: nextS}
break
}
cv = uint32(now)
s = nextS
}
// A 4-byte match has been found. We'll later see if more than 4 bytes
// match. But, prior to the match, src[nextEmit:s] are unmatched. Emit
// them as literal bytes.
for {
// Invariant: we have a 4-byte match at s, and no need to emit any
// literal bytes prior to s.
// Extend the 4-byte match as long as possible.
t := candidate.offset
l := int16(matchLen(src[s+4:], src[t+4:]) + 4)
// Extend backwards
for t > 0 && s > nextEmit && src[t-1] == src[s-1] {
s--
t--
l++
}
if nextEmit < s {
emitLiteral(dst, src[nextEmit:s])
}
// Save the match found
dst.AddMatchLong(int32(l), uint32(s-t-baseMatchOffset))
s += l
nextEmit = s
if nextS >= s {
s = nextS + 1
}
if s >= sLimit {
goto emitRemainder
}
// We could immediately start working at s now, but to improve
// compression we first update the hash table at s-2 and at s. If
// another emitCopy is not our next move, also calculate nextHash
// at s+1. At least on GOARCH=amd64, these three hash calculations
// are faster as one load64 call (with some shifts) instead of
// three load32 calls.
x := load6416(src, s-2)
o := s - 2
prevHash := hashSL(uint32(x))
table[prevHash] = tableEntry{offset: o}
x >>= 16
currHash := hashSL(uint32(x))
candidate = table[currHash]
table[currHash] = tableEntry{offset: o + 2}
if uint32(x) != load3216(src, candidate.offset) {
cv = uint32(x >> 8)
s++
break
}
}
}
emitRemainder:
if int(nextEmit) < len(src) {
// If nothing was added, don't encode literals.
if dst.n == 0 {
return
}
emitLiteral(dst, src[nextEmit:])
}
}

306
vendor/github.com/klauspost/compress/flate/token.go generated vendored
View file

@ -4,7 +4,13 @@
package flate
import "fmt"
import (
"bytes"
"encoding/binary"
"fmt"
"io"
"math"
)
const (
// 2 bits: type 0 = literal 1=EOF 2=Match 3=Unused
@ -19,7 +25,7 @@ const (
// The length code for length X (MIN_MATCH_LENGTH <= X <= MAX_MATCH_LENGTH)
// is lengthCodes[length - MIN_MATCH_LENGTH]
var lengthCodes = [...]uint32{
var lengthCodes = [256]uint8{
0, 1, 2, 3, 4, 5, 6, 7, 8, 8,
9, 9, 10, 10, 11, 11, 12, 12, 12, 12,
13, 13, 13, 13, 14, 14, 14, 14, 15, 15,
@ -48,7 +54,37 @@ var lengthCodes = [...]uint32{
27, 27, 27, 27, 27, 28,
}
var offsetCodes = [...]uint32{
// lengthCodes1 is length codes, but starting at 1.
var lengthCodes1 = [256]uint8{
1, 2, 3, 4, 5, 6, 7, 8, 9, 9,
10, 10, 11, 11, 12, 12, 13, 13, 13, 13,
14, 14, 14, 14, 15, 15, 15, 15, 16, 16,
16, 16, 17, 17, 17, 17, 17, 17, 17, 17,
18, 18, 18, 18, 18, 18, 18, 18, 19, 19,
19, 19, 19, 19, 19, 19, 20, 20, 20, 20,
20, 20, 20, 20, 21, 21, 21, 21, 21, 21,
21, 21, 21, 21, 21, 21, 21, 21, 21, 21,
22, 22, 22, 22, 22, 22, 22, 22, 22, 22,
22, 22, 22, 22, 22, 22, 23, 23, 23, 23,
23, 23, 23, 23, 23, 23, 23, 23, 23, 23,
23, 23, 24, 24, 24, 24, 24, 24, 24, 24,
24, 24, 24, 24, 24, 24, 24, 24, 25, 25,
25, 25, 25, 25, 25, 25, 25, 25, 25, 25,
25, 25, 25, 25, 25, 25, 25, 25, 25, 25,
25, 25, 25, 25, 25, 25, 25, 25, 25, 25,
26, 26, 26, 26, 26, 26, 26, 26, 26, 26,
26, 26, 26, 26, 26, 26, 26, 26, 26, 26,
26, 26, 26, 26, 26, 26, 26, 26, 26, 26,
26, 26, 27, 27, 27, 27, 27, 27, 27, 27,
27, 27, 27, 27, 27, 27, 27, 27, 27, 27,
27, 27, 27, 27, 27, 27, 27, 27, 27, 27,
27, 27, 27, 27, 28, 28, 28, 28, 28, 28,
28, 28, 28, 28, 28, 28, 28, 28, 28, 28,
28, 28, 28, 28, 28, 28, 28, 28, 28, 28,
28, 28, 28, 28, 28, 29,
}
var offsetCodes = [256]uint32{
0, 1, 2, 3, 4, 4, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7,
8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9,
10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10,
@ -67,49 +103,265 @@ var offsetCodes = [...]uint32{
15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
}
// offsetCodes14 are offsetCodes, but with 14 added.
var offsetCodes14 = [256]uint32{
14, 15, 16, 17, 18, 18, 19, 19, 20, 20, 20, 20, 21, 21, 21, 21,
22, 22, 22, 22, 22, 22, 22, 22, 23, 23, 23, 23, 23, 23, 23, 23,
24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25,
26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26,
26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26,
27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27,
27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27,
28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28,
28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28,
28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28,
28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28,
29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29,
29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29,
29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29,
29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29,
}
type token uint32
type tokens struct {
tokens [maxStoreBlockSize + 1]token
n uint16 // Must be able to contain maxStoreBlockSize
nLits int
extraHist [32]uint16 // codes 256->maxnumlit
offHist [32]uint16 // offset codes
litHist [256]uint16 // codes 0->255
n uint16 // Must be able to contain maxStoreBlockSize
tokens [maxStoreBlockSize + 1]token
}
// Convert a literal into a literal token.
func literalToken(literal uint32) token { return token(literalType + literal) }
// Convert a < xlength, xoffset > pair into a match token.
func matchToken(xlength uint32, xoffset uint32) token {
return token(matchType + xlength<<lengthShift + xoffset)
}
func matchTokend(xlength uint32, xoffset uint32) token {
if xlength > maxMatchLength || xoffset > maxMatchOffset {
panic(fmt.Sprintf("Invalid match: len: %d, offset: %d\n", xlength, xoffset))
return token(matchType)
func (t *tokens) Reset() {
if t.n == 0 {
return
}
return token(matchType + xlength<<lengthShift + xoffset)
t.n = 0
t.nLits = 0
for i := range t.litHist[:] {
t.litHist[i] = 0
}
for i := range t.extraHist[:] {
t.extraHist[i] = 0
}
for i := range t.offHist[:] {
t.offHist[i] = 0
}
}
func (t *tokens) Fill() {
if t.n == 0 {
return
}
for i, v := range t.litHist[:] {
if v == 0 {
t.litHist[i] = 1
t.nLits++
}
}
for i, v := range t.extraHist[:literalCount-256] {
if v == 0 {
t.nLits++
t.extraHist[i] = 1
}
}
for i, v := range t.offHist[:offsetCodeCount] {
if v == 0 {
t.offHist[i] = 1
}
}
}
func indexTokens(in []token) tokens {
var t tokens
t.indexTokens(in)
return t
}
func (t *tokens) indexTokens(in []token) {
t.Reset()
for _, tok := range in {
if tok < matchType {
t.tokens[t.n] = tok
t.litHist[tok]++
t.n++
continue
}
t.AddMatch(uint32(tok.length()), tok.offset())
}
}
// emitLiteral writes a literal chunk and returns the number of bytes written.
func emitLiteral(dst *tokens, lit []byte) {
ol := int(dst.n)
for i, v := range lit {
dst.tokens[(i+ol)&maxStoreBlockSize] = token(v)
dst.litHist[v]++
}
dst.n += uint16(len(lit))
dst.nLits += len(lit)
}
func (t *tokens) AddLiteral(lit byte) {
t.tokens[t.n] = token(lit)
t.litHist[lit]++
t.n++
t.nLits++
}
// EstimatedBits will return an minimum size estimated by an *optimal*
// compression of the block.
// The size of the block
func (t *tokens) EstimatedBits() int {
shannon := float64(0)
bits := int(0)
nMatches := 0
if t.nLits > 0 {
invTotal := 1.0 / float64(t.nLits)
for _, v := range t.litHist[:] {
if v > 0 {
n := float64(v)
shannon += math.Ceil(-math.Log2(n*invTotal) * n)
}
}
// Just add 15 for EOB
shannon += 15
for _, v := range t.extraHist[1 : literalCount-256] {
if v > 0 {
n := float64(v)
shannon += math.Ceil(-math.Log2(n*invTotal) * n)
bits += int(lengthExtraBits[v&31]) * int(v)
nMatches += int(v)
}
}
}
if nMatches > 0 {
invTotal := 1.0 / float64(nMatches)
for _, v := range t.offHist[:offsetCodeCount] {
if v > 0 {
n := float64(v)
shannon += math.Ceil(-math.Log2(n*invTotal) * n)
bits += int(offsetExtraBits[v&31]) * int(n)
}
}
}
return int(shannon) + bits
}
// AddMatch adds a match to the tokens.
// This function is very sensitive to inlining and right on the border.
func (t *tokens) AddMatch(xlength uint32, xoffset uint32) {
if debugDecode {
if xlength >= maxMatchLength+baseMatchLength {
panic(fmt.Errorf("invalid length: %v", xlength))
}
if xoffset >= maxMatchOffset+baseMatchOffset {
panic(fmt.Errorf("invalid offset: %v", xoffset))
}
}
t.nLits++
lengthCode := lengthCodes1[uint8(xlength)] & 31
t.tokens[t.n] = token(matchType | xlength<<lengthShift | xoffset)
t.extraHist[lengthCode]++
t.offHist[offsetCode(xoffset)&31]++
t.n++
}
// AddMatchLong adds a match to the tokens, potentially longer than max match length.
// Length should NOT have the base subtracted, only offset should.
func (t *tokens) AddMatchLong(xlength int32, xoffset uint32) {
if debugDecode {
if xoffset >= maxMatchOffset+baseMatchOffset {
panic(fmt.Errorf("invalid offset: %v", xoffset))
}
}
oc := offsetCode(xoffset) & 31
for xlength > 0 {
xl := xlength
if xl > 258 {
// We need to have at least baseMatchLength left over for next loop.
xl = 258 - baseMatchLength
}
xlength -= xl
xl -= 3
t.nLits++
lengthCode := lengthCodes1[uint8(xl)] & 31
t.tokens[t.n] = token(matchType | uint32(xl)<<lengthShift | xoffset)
t.extraHist[lengthCode]++
t.offHist[oc]++
t.n++
}
}
func (t *tokens) AddEOB() {
t.tokens[t.n] = token(endBlockMarker)
t.extraHist[0]++
t.n++
}
func (t *tokens) Slice() []token {
return t.tokens[:t.n]
}
// VarInt returns the tokens as varint encoded bytes.
func (t *tokens) VarInt() []byte {
var b = make([]byte, binary.MaxVarintLen32*int(t.n))
var off int
for _, v := range t.tokens[:t.n] {
off += binary.PutUvarint(b[off:], uint64(v))
}
return b[:off]
}
// FromVarInt restores t to the varint encoded tokens provided.
// Any data in t is removed.
func (t *tokens) FromVarInt(b []byte) error {
var buf = bytes.NewReader(b)
var toks []token
for {
r, err := binary.ReadUvarint(buf)
if err == io.EOF {
break
}
if err != nil {
return err
}
toks = append(toks, token(r))
}
t.indexTokens(toks)
return nil
}
// Returns the type of a token
func (t token) typ() uint32 { return uint32(t) & typeMask }
// Returns the literal of a literal token
func (t token) literal() uint32 { return uint32(t - literalType) }
func (t token) literal() uint8 { return uint8(t) }
// Returns the extra offset of a match token
func (t token) offset() uint32 { return uint32(t) & offsetMask }
func (t token) length() uint32 { return uint32((t - matchType) >> lengthShift) }
func (t token) length() uint8 { return uint8(t >> lengthShift) }
func lengthCode(len uint32) uint32 { return lengthCodes[len] }
// The code is never more than 8 bits, but is returned as uint32 for convenience.
func lengthCode(len uint8) uint32 { return uint32(lengthCodes[len]) }
// Returns the offset code corresponding to a specific offset
func offsetCode(off uint32) uint32 {
if off < uint32(len(offsetCodes)) {
return offsetCodes[off]
} else if off>>7 < uint32(len(offsetCodes)) {
return offsetCodes[off>>7] + 14
} else {
return offsetCodes[off>>14] + 28
if false {
if off < uint32(len(offsetCodes)) {
return offsetCodes[off&255]
} else if off>>7 < uint32(len(offsetCodes)) {
return offsetCodes[(off>>7)&255] + 14
} else {
return offsetCodes[(off>>14)&255] + 28
}
}
if off < uint32(len(offsetCodes)) {
return offsetCodes[uint8(off)]
}
return offsetCodes14[uint8(off>>7)]
}

2
vendor/github.com/klauspost/compress/gzip/gunzip.go generated vendored
View file

@ -10,11 +10,11 @@ import (
"bufio"
"encoding/binary"
"errors"
"hash/crc32"
"io"
"time"
"github.com/klauspost/compress/flate"
"github.com/klauspost/crc32"
)
const (

32
vendor/github.com/klauspost/compress/gzip/gzip.go generated vendored
View file

@ -7,10 +7,10 @@ package gzip
import (
"errors"
"fmt"
"hash/crc32"
"io"
"github.com/klauspost/compress/flate"
"github.com/klauspost/crc32"
)
// These constants are copied from the flate package, so that code that imports
@ -22,6 +22,13 @@ const (
DefaultCompression = flate.DefaultCompression
ConstantCompression = flate.ConstantCompression
HuffmanOnly = flate.HuffmanOnly
// StatelessCompression will do compression but without maintaining any state
// between Write calls.
// There will be no memory kept between Write calls,
// but compression and speed will be suboptimal.
// Because of this, the size of actual Write calls will affect output size.
StatelessCompression = -3
)
// A Writer is an io.WriteCloser.
@ -59,7 +66,7 @@ func NewWriter(w io.Writer) *Writer {
// integer value between BestSpeed and BestCompression inclusive. The error
// returned will be nil if the level is valid.
func NewWriterLevel(w io.Writer, level int) (*Writer, error) {
if level < HuffmanOnly || level > BestCompression {
if level < StatelessCompression || level > BestCompression {
return nil, fmt.Errorf("gzip: invalid compression level: %d", level)
}
z := new(Writer)
@ -69,9 +76,12 @@ func NewWriterLevel(w io.Writer, level int) (*Writer, error) {
func (z *Writer) init(w io.Writer, level int) {
compressor := z.compressor
if compressor != nil {
compressor.Reset(w)
if level != StatelessCompression {
if compressor != nil {
compressor.Reset(w)
}
}
*z = Writer{
Header: Header{
OS: 255, // unknown
@ -189,12 +199,16 @@ func (z *Writer) Write(p []byte) (int, error) {
return n, z.err
}
}
if z.compressor == nil {
if z.compressor == nil && z.level != StatelessCompression {
z.compressor, _ = flate.NewWriter(z.w, z.level)
}
}
z.size += uint32(len(p))
z.digest = crc32.Update(z.digest, crc32.IEEETable, p)
if z.level == StatelessCompression {
return len(p), flate.StatelessDeflate(z.w, p, false)
}
n, z.err = z.compressor.Write(p)
return n, z.err
}
@ -211,7 +225,7 @@ func (z *Writer) Flush() error {
if z.err != nil {
return z.err
}
if z.closed {
if z.closed || z.level == StatelessCompression {
return nil
}
if !z.wroteHeader {
@ -240,7 +254,11 @@ func (z *Writer) Close() error {
return z.err
}
}
z.err = z.compressor.Close()
if z.level == StatelessCompression {
z.err = flate.StatelessDeflate(z.w, nil, true)
} else {
z.err = z.compressor.Close()
}
if z.err != nil {
return z.err
}