[Vendor] blevesearch v0.8.1 -> v1.0.7 (#11360)

* Update blevesearch v0.8.1 -> v1.0.7

* make vendor

Co-authored-by: zeripath <art27@cantab.net>

vendor/github.com/blevesearch/zap/v12/intcoder.go

@@ -0,0 +1,203 @@
+//  Copyright (c) 2017 Couchbase, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 		http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package zap
+
+import (
+	"bytes"
+	"encoding/binary"
+	"io"
+	"math"
+)
+
+const termNotEncoded = math.MaxUint64
+
+type chunkedIntCoder struct {
+	final     []byte
+	chunkSize uint64
+	chunkBuf  bytes.Buffer
+	chunkLens []uint64
+	currChunk uint64
+
+	buf []byte
+}
+
+// newChunkedIntCoder returns a new chunk int coder which packs data into
+// chunks based on the provided chunkSize and supports up to the specified
+// maxDocNum
+func newChunkedIntCoder(chunkSize uint64, maxDocNum uint64) *chunkedIntCoder {
+	total := maxDocNum/chunkSize + 1
+	rv := &chunkedIntCoder{
+		chunkSize: chunkSize,
+		chunkLens: make([]uint64, total),
+		final:     make([]byte, 0, 64),
+	}
+
+	return rv
+}
+
+// Reset lets you reuse this chunked int coder.  buffers are reset and reused
+// from previous use.  you cannot change the chunk size or max doc num.
+func (c *chunkedIntCoder) Reset() {
+	c.final = c.final[:0]
+	c.chunkBuf.Reset()
+	c.currChunk = 0
+	for i := range c.chunkLens {
+		c.chunkLens[i] = 0
+	}
+}
+
+// SetChunkSize changes the chunk size.  It is only valid to do so
+// with a new chunkedIntCoder, or immediately after calling Reset()
+func (c *chunkedIntCoder) SetChunkSize(chunkSize uint64, maxDocNum uint64) {
+	total := int(maxDocNum/chunkSize + 1)
+	c.chunkSize = chunkSize
+	if cap(c.chunkLens) < total {
+		c.chunkLens = make([]uint64, total)
+	} else {
+		c.chunkLens = c.chunkLens[:total]
+	}
+}
+
+// Add encodes the provided integers into the correct chunk for the provided
+// doc num.  You MUST call Add() with increasing docNums.
+func (c *chunkedIntCoder) Add(docNum uint64, vals ...uint64) error {
+	chunk := docNum / c.chunkSize
+	if chunk != c.currChunk {
+		// starting a new chunk
+		c.Close()
+		c.chunkBuf.Reset()
+		c.currChunk = chunk
+	}
+
+	if len(c.buf) < binary.MaxVarintLen64 {
+		c.buf = make([]byte, binary.MaxVarintLen64)
+	}
+
+	for _, val := range vals {
+		wb := binary.PutUvarint(c.buf, val)
+		_, err := c.chunkBuf.Write(c.buf[:wb])
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (c *chunkedIntCoder) AddBytes(docNum uint64, buf []byte) error {
+	chunk := docNum / c.chunkSize
+	if chunk != c.currChunk {
+		// starting a new chunk
+		c.Close()
+		c.chunkBuf.Reset()
+		c.currChunk = chunk
+	}
+
+	_, err := c.chunkBuf.Write(buf)
+	return err
+}
+
+// Close indicates you are done calling Add() this allows the final chunk
+// to be encoded.
+func (c *chunkedIntCoder) Close() {
+	encodingBytes := c.chunkBuf.Bytes()
+	c.chunkLens[c.currChunk] = uint64(len(encodingBytes))
+	c.final = append(c.final, encodingBytes...)
+	c.currChunk = uint64(cap(c.chunkLens)) // sentinel to detect double close
+}
+
+// Write commits all the encoded chunked integers to the provided writer.
+func (c *chunkedIntCoder) Write(w io.Writer) (int, error) {
+	bufNeeded := binary.MaxVarintLen64 * (1 + len(c.chunkLens))
+	if len(c.buf) < bufNeeded {
+		c.buf = make([]byte, bufNeeded)
+	}
+	buf := c.buf
+
+	// convert the chunk lengths into chunk offsets
+	chunkOffsets := modifyLengthsToEndOffsets(c.chunkLens)
+
+	// write out the number of chunks & each chunk offsets
+	n := binary.PutUvarint(buf, uint64(len(chunkOffsets)))
+	for _, chunkOffset := range chunkOffsets {
+		n += binary.PutUvarint(buf[n:], chunkOffset)
+	}
+
+	tw, err := w.Write(buf[:n])
+	if err != nil {
+		return tw, err
+	}
+
+	// write out the data
+	nw, err := w.Write(c.final)
+	tw += nw
+	if err != nil {
+		return tw, err
+	}
+	return tw, nil
+}
+
+// writeAt commits all the encoded chunked integers to the provided writer
+// and returns the starting offset, total bytes written and an error
+func (c *chunkedIntCoder) writeAt(w io.Writer) (uint64, int, error) {
+	startOffset := uint64(termNotEncoded)
+	if len(c.final) <= 0 {
+		return startOffset, 0, nil
+	}
+
+	if chw := w.(*CountHashWriter); chw != nil {
+		startOffset = uint64(chw.Count())
+	}
+
+	tw, err := c.Write(w)
+	return startOffset, tw, err
+}
+
+func (c *chunkedIntCoder) FinalSize() int {
+	return len(c.final)
+}
+
+// modifyLengthsToEndOffsets converts the chunk length array
+// to a chunk offset array. The readChunkBoundary
+// will figure out the start and end of every chunk from
+// these offsets. Starting offset of i'th index is stored
+// in i-1'th position except for 0'th index and ending offset
+// is stored at i'th index position.
+// For 0'th element, starting position is always zero.
+// eg:
+// Lens ->  5 5 5 5 => 5 10 15 20
+// Lens ->  0 5 0 5 => 0 5 5 10
+// Lens ->  0 0 0 5 => 0 0 0 5
+// Lens ->  5 0 0 0 => 5 5 5 5
+// Lens ->  0 5 0 0 => 0 5 5 5
+// Lens ->  0 0 5 0 => 0 0 5 5
+func modifyLengthsToEndOffsets(lengths []uint64) []uint64 {
+	var runningOffset uint64
+	var index, i int
+	for i = 1; i <= len(lengths); i++ {
+		runningOffset += lengths[i-1]
+		lengths[index] = runningOffset
+		index++
+	}
+	return lengths
+}
+
+func readChunkBoundary(chunk int, offsets []uint64) (uint64, uint64) {
+	var start uint64
+	if chunk > 0 {
+		start = offsets[chunk-1]
+	}
+	return start, offsets[chunk]
+}