deps: update and fix chardet import (#9351)

vendor/github.com/gogs/chardet/unicode.go

@@ -0,0 +1,103 @@
+package chardet
+
+import (
+	"bytes"
+)
+
+var (
+	utf16beBom = []byte{0xFE, 0xFF}
+	utf16leBom = []byte{0xFF, 0xFE}
+	utf32beBom = []byte{0x00, 0x00, 0xFE, 0xFF}
+	utf32leBom = []byte{0xFF, 0xFE, 0x00, 0x00}
+)
+
+type recognizerUtf16be struct {
+}
+
+func newRecognizer_utf16be() *recognizerUtf16be {
+	return &recognizerUtf16be{}
+}
+
+func (*recognizerUtf16be) Match(input *recognizerInput) (output recognizerOutput) {
+	output = recognizerOutput{
+		Charset: "UTF-16BE",
+	}
+	if bytes.HasPrefix(input.raw, utf16beBom) {
+		output.Confidence = 100
+	}
+	return
+}
+
+type recognizerUtf16le struct {
+}
+
+func newRecognizer_utf16le() *recognizerUtf16le {
+	return &recognizerUtf16le{}
+}
+
+func (*recognizerUtf16le) Match(input *recognizerInput) (output recognizerOutput) {
+	output = recognizerOutput{
+		Charset: "UTF-16LE",
+	}
+	if bytes.HasPrefix(input.raw, utf16leBom) && !bytes.HasPrefix(input.raw, utf32leBom) {
+		output.Confidence = 100
+	}
+	return
+}
+
+type recognizerUtf32 struct {
+	name       string
+	bom        []byte
+	decodeChar func(input []byte) uint32
+}
+
+func decodeUtf32be(input []byte) uint32 {
+	return uint32(input[0])<<24 | uint32(input[1])<<16 | uint32(input[2])<<8 | uint32(input[3])
+}
+
+func decodeUtf32le(input []byte) uint32 {
+	return uint32(input[3])<<24 | uint32(input[2])<<16 | uint32(input[1])<<8 | uint32(input[0])
+}
+
+func newRecognizer_utf32be() *recognizerUtf32 {
+	return &recognizerUtf32{
+		"UTF-32BE",
+		utf32beBom,
+		decodeUtf32be,
+	}
+}
+
+func newRecognizer_utf32le() *recognizerUtf32 {
+	return &recognizerUtf32{
+		"UTF-32LE",
+		utf32leBom,
+		decodeUtf32le,
+	}
+}
+
+func (r *recognizerUtf32) Match(input *recognizerInput) (output recognizerOutput) {
+	output = recognizerOutput{
+		Charset: r.name,
+	}
+	hasBom := bytes.HasPrefix(input.raw, r.bom)
+	var numValid, numInvalid uint32
+	for b := input.raw; len(b) >= 4; b = b[4:] {
+		if c := r.decodeChar(b); c >= 0x10FFFF || (c >= 0xD800 && c <= 0xDFFF) {
+			numInvalid++
+		} else {
+			numValid++
+		}
+	}
+	if hasBom && numInvalid == 0 {
+		output.Confidence = 100
+	} else if hasBom && numValid > numInvalid*10 {
+		output.Confidence = 80
+	} else if numValid > 3 && numInvalid == 0 {
+		output.Confidence = 100
+	} else if numValid > 0 && numInvalid == 0 {
+		output.Confidence = 80
+	} else if numValid > numInvalid*10 {
+		output.Confidence = 25
+	}
+	return
+}