diff options
Diffstat (limited to 'vendor/golang.org/x/text/encoding/unicode/utf32')
| -rw-r--r-- | vendor/golang.org/x/text/encoding/unicode/utf32/utf32.go | 296 |
1 files changed, 0 insertions, 296 deletions
diff --git a/vendor/golang.org/x/text/encoding/unicode/utf32/utf32.go b/vendor/golang.org/x/text/encoding/unicode/utf32/utf32.go deleted file mode 100644 index 48b21521..00000000 --- a/vendor/golang.org/x/text/encoding/unicode/utf32/utf32.go +++ /dev/null @@ -1,296 +0,0 @@ -// Copyright 2016 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 utf32 provides the UTF-32 Unicode encoding. -// -// Please note that support for UTF-32 is discouraged as it is a rare and -// inefficient encoding, unfit for use as an interchange format. For use -// on the web, the W3C strongly discourages its use -// (https://www.w3.org/TR/html5/document-metadata.html#charset) -// while WHATWG directly prohibits supporting it -// (https://html.spec.whatwg.org/multipage/syntax.html#character-encodings). -package utf32 // import "golang.org/x/text/encoding/unicode/utf32" - -import ( - "errors" - "unicode/utf8" - - "golang.org/x/text/encoding" - "golang.org/x/text/encoding/internal/identifier" - "golang.org/x/text/transform" -) - -// All lists a configuration for each IANA-defined UTF-32 variant. -var All = []encoding.Encoding{ - UTF32(BigEndian, UseBOM), - UTF32(BigEndian, IgnoreBOM), - UTF32(LittleEndian, IgnoreBOM), -} - -// ErrMissingBOM means that decoding UTF-32 input with ExpectBOM did not -// find a starting byte order mark. -var ErrMissingBOM = errors.New("encoding: missing byte order mark") - -// UTF32 returns a UTF-32 Encoding for the given default endianness and -// byte order mark (BOM) policy. -// -// When decoding from UTF-32 to UTF-8, if the BOMPolicy is IgnoreBOM then -// neither BOMs U+FEFF nor ill-formed code units 0xFFFE0000 in the input -// stream will affect the endianness used for decoding. Instead BOMs will -// be output as their standard UTF-8 encoding "\xef\xbb\xbf" while -// 0xFFFE0000 code units will be output as "\xef\xbf\xbd", the standard -// UTF-8 encoding for the Unicode replacement character. If the BOMPolicy -// is UseBOM or ExpectBOM a starting BOM is not written to the UTF-8 -// output. Instead, it overrides the default endianness e for the remainder -// of the transformation. Any subsequent BOMs U+FEFF or ill-formed code -// units 0xFFFE0000 will not affect the endianness used, and will instead -// be output as their standard UTF-8 (replacement) encodings. For UseBOM, -// if there is no starting BOM, it will proceed with the default -// Endianness. For ExpectBOM, in that case, the transformation will return -// early with an ErrMissingBOM error. -// -// When encoding from UTF-8 to UTF-32, a BOM will be inserted at the start -// of the output if the BOMPolicy is UseBOM or ExpectBOM. Otherwise, a BOM -// will not be inserted. The UTF-8 input does not need to contain a BOM. -// -// There is no concept of a 'native' endianness. If the UTF-32 data is -// produced and consumed in a greater context that implies a certain -// endianness, use IgnoreBOM. Otherwise, use ExpectBOM and always produce -// and consume a BOM. -// -// In the language of http://www.unicode.org/faq/utf_bom.html#bom10, -// IgnoreBOM corresponds to "Where the precise type of the data stream is -// known... the BOM should not be used" and ExpectBOM corresponds to "A -// particular protocol... may require use of the BOM". -func UTF32(e Endianness, b BOMPolicy) encoding.Encoding { - return utf32Encoding{config{e, b}, mibValue[e][b&bomMask]} -} - -// mibValue maps Endianness and BOMPolicy settings to MIB constants for UTF-32. -// Note that some configurations map to the same MIB identifier. -var mibValue = map[Endianness][numBOMValues]identifier.MIB{ - BigEndian: [numBOMValues]identifier.MIB{ - IgnoreBOM: identifier.UTF32BE, - UseBOM: identifier.UTF32, - }, - LittleEndian: [numBOMValues]identifier.MIB{ - IgnoreBOM: identifier.UTF32LE, - UseBOM: identifier.UTF32, - }, - // ExpectBOM is not widely used and has no valid MIB identifier. -} - -// BOMPolicy is a UTF-32 encodings's byte order mark policy. -type BOMPolicy uint8 - -const ( - writeBOM BOMPolicy = 0x01 - acceptBOM BOMPolicy = 0x02 - requireBOM BOMPolicy = 0x04 - bomMask BOMPolicy = 0x07 - - // HACK: numBOMValues == 8 triggers a bug in the 1.4 compiler (cannot have a - // map of an array of length 8 of a type that is also used as a key or value - // in another map). See golang.org/issue/11354. - // TODO: consider changing this value back to 8 if the use of 1.4.* has - // been minimized. - numBOMValues = 8 + 1 - - // IgnoreBOM means to ignore any byte order marks. - IgnoreBOM BOMPolicy = 0 - // Unicode-compliant interpretation for UTF-32BE/LE. - - // UseBOM means that the UTF-32 form may start with a byte order mark, - // which will be used to override the default encoding. - UseBOM BOMPolicy = writeBOM | acceptBOM - // Unicode-compliant interpretation for UTF-32. - - // ExpectBOM means that the UTF-32 form must start with a byte order mark, - // which will be used to override the default encoding. - ExpectBOM BOMPolicy = writeBOM | acceptBOM | requireBOM - // Consistent with BOMPolicy definition in golang.org/x/text/encoding/unicode -) - -// Endianness is a UTF-32 encoding's default endianness. -type Endianness bool - -const ( - // BigEndian is UTF-32BE. - BigEndian Endianness = false - // LittleEndian is UTF-32LE. - LittleEndian Endianness = true -) - -type config struct { - endianness Endianness - bomPolicy BOMPolicy -} - -type utf32Encoding struct { - config - mib identifier.MIB -} - -func (u utf32Encoding) NewDecoder() *encoding.Decoder { - return &encoding.Decoder{Transformer: &utf32Decoder{ - initial: u.config, - current: u.config, - }} -} - -func (u utf32Encoding) NewEncoder() *encoding.Encoder { - return &encoding.Encoder{Transformer: &utf32Encoder{ - endianness: u.endianness, - initialBOMPolicy: u.bomPolicy, - currentBOMPolicy: u.bomPolicy, - }} -} - -func (u utf32Encoding) ID() (mib identifier.MIB, other string) { - return u.mib, "" -} - -func (u utf32Encoding) String() string { - e, b := "B", "" - if u.endianness == LittleEndian { - e = "L" - } - switch u.bomPolicy { - case ExpectBOM: - b = "Expect" - case UseBOM: - b = "Use" - case IgnoreBOM: - b = "Ignore" - } - return "UTF-32" + e + "E (" + b + " BOM)" -} - -type utf32Decoder struct { - initial config - current config -} - -func (u *utf32Decoder) Reset() { - u.current = u.initial -} - -func (u *utf32Decoder) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) { - if len(src) == 0 { - if atEOF && u.current.bomPolicy&requireBOM != 0 { - return 0, 0, ErrMissingBOM - } - return 0, 0, nil - } - if u.current.bomPolicy&acceptBOM != 0 { - if len(src) < 4 { - return 0, 0, transform.ErrShortSrc - } - switch { - case src[0] == 0x00 && src[1] == 0x00 && src[2] == 0xfe && src[3] == 0xff: - u.current.endianness = BigEndian - nSrc = 4 - case src[0] == 0xff && src[1] == 0xfe && src[2] == 0x00 && src[3] == 0x00: - u.current.endianness = LittleEndian - nSrc = 4 - default: - if u.current.bomPolicy&requireBOM != 0 { - return 0, 0, ErrMissingBOM - } - } - u.current.bomPolicy = IgnoreBOM - } - - var r rune - var dSize, sSize int - for nSrc < len(src) { - if nSrc+3 < len(src) { - x := uint32(src[nSrc+0])<<24 | uint32(src[nSrc+1])<<16 | - uint32(src[nSrc+2])<<8 | uint32(src[nSrc+3]) - if u.current.endianness == LittleEndian { - x = x>>24 | (x >> 8 & 0x0000FF00) | (x << 8 & 0x00FF0000) | x<<24 - } - r, sSize = rune(x), 4 - if dSize = utf8.RuneLen(r); dSize < 0 { - r, dSize = utf8.RuneError, 3 - } - } else if atEOF { - // 1..3 trailing bytes. - r, dSize, sSize = utf8.RuneError, 3, len(src)-nSrc - } else { - err = transform.ErrShortSrc - break - } - if nDst+dSize > len(dst) { - err = transform.ErrShortDst - break - } - nDst += utf8.EncodeRune(dst[nDst:], r) - nSrc += sSize - } - return nDst, nSrc, err -} - -type utf32Encoder struct { - endianness Endianness - initialBOMPolicy BOMPolicy - currentBOMPolicy BOMPolicy -} - -func (u *utf32Encoder) Reset() { - u.currentBOMPolicy = u.initialBOMPolicy -} - -func (u *utf32Encoder) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) { - if u.currentBOMPolicy&writeBOM != 0 { - if len(dst) < 4 { - return 0, 0, transform.ErrShortDst - } - dst[0], dst[1], dst[2], dst[3] = 0x00, 0x00, 0xfe, 0xff - u.currentBOMPolicy = IgnoreBOM - nDst = 4 - } - - r, size := rune(0), 0 - for nSrc < len(src) { - r = rune(src[nSrc]) - - // Decode a 1-byte rune. - if r < utf8.RuneSelf { - size = 1 - - } else { - // Decode a multi-byte rune. - r, size = utf8.DecodeRune(src[nSrc:]) - if size == 1 { - // All valid runes of size 1 (those below utf8.RuneSelf) were - // handled above. We have invalid UTF-8 or we haven't seen the - // full character yet. - if !atEOF && !utf8.FullRune(src[nSrc:]) { - err = transform.ErrShortSrc - break - } - } - } - - if nDst+4 > len(dst) { - err = transform.ErrShortDst - break - } - - dst[nDst+0] = uint8(r >> 24) - dst[nDst+1] = uint8(r >> 16) - dst[nDst+2] = uint8(r >> 8) - dst[nDst+3] = uint8(r) - nDst += 4 - nSrc += size - } - - if u.endianness == LittleEndian { - for i := 0; i < nDst; i += 4 { - dst[i], dst[i+1], dst[i+2], dst[i+3] = dst[i+3], dst[i+2], dst[i+1], dst[i] - } - } - return nDst, nSrc, err -} |