// Copyright 2013 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 simplifiedchinese import ( "unicode/utf8" "golang.org/x/text/encoding" "golang.org/x/text/encoding/internal" "golang.org/x/text/encoding/internal/identifier" "golang.org/x/text/transform" ) var ( // GB18030 is the GB18030 encoding. GB18030 encoding.Encoding = &gbk18030 // GBK is the GBK encoding. It encodes an extension of the GB2312 character set // and is also known as Code Page 936. GBK encoding.Encoding = &gbk ) var gbk = internal.Encoding{ &internal.SimpleEncoding{ gbkDecoder{gb18030: false}, gbkEncoder{gb18030: false}, }, "GBK", identifier.GBK, } var gbk18030 = internal.Encoding{ &internal.SimpleEncoding{ gbkDecoder{gb18030: true}, gbkEncoder{gb18030: true}, }, "GB18030", identifier.GB18030, } type gbkDecoder struct { transform.NopResetter gb18030 bool } func (d gbkDecoder) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) { r, size := rune(0), 0 loop: for ; nSrc < len(src); nSrc += size { switch c0 := src[nSrc]; { case c0 < utf8.RuneSelf: r, size = rune(c0), 1 // Microsoft's Code Page 936 extends GBK 1.0 to encode the euro sign U+20AC // as 0x80. The HTML5 specification at http://encoding.spec.whatwg.org/#gbk // says to treat "gbk" as Code Page 936. case c0 == 0x80: r, size = '€', 1 case c0 < 0xff: if nSrc+1 >= len(src) { if !atEOF { err = transform.ErrShortSrc break loop } r, size = utf8.RuneError, 1 goto write } c1 := src[nSrc+1] switch { case 0x40 <= c1 && c1 < 0x7f: c1 -= 0x40 case 0x80 <= c1 && c1 < 0xff: c1 -= 0x41 case d.gb18030 && 0x30 <= c1 && c1 < 0x40: if nSrc+3 >= len(src) { if !atEOF { err = transform.ErrShortSrc break loop } // The second byte here is always ASCII, so we can set size // to 1 in all cases. r, size = utf8.RuneError, 1 goto write } c2 := src[nSrc+2] if c2 < 0x81 || 0xff <= c2 { r, size = utf8.RuneError, 1 goto write } c3 := src[nSrc+3] if c3 < 0x30 || 0x3a <= c3 { r, size = utf8.RuneError, 1 goto write } size = 4 r = ((rune(c0-0x81)*10+rune(c1-0x30))*126+rune(c2-0x81))*10 + rune(c3-0x30) if r < 39420 { i, j := 0, len(gb18030) for i < j { h := i + (j-i)/2 if r >= rune(gb18030[h][0]) { i = h + 1 } else { j = h } } dec := &gb18030[i-1] r += rune(dec[1]) - rune(dec[0]) goto write } r -= 189000 if 0 <= r && r < 0x100000 { r += 0x10000 } else { r, size = utf8.RuneError, 1 } goto write default: r, size = utf8.RuneError, 1 goto write } r, size = '\ufffd', 2 if i := int(c0-0x81)*190 + int(c1); i < len(decode) { r = rune(decode[i]) if r == 0 { r = '\ufffd' } } default: r, size = utf8.RuneError, 1 } write: if nDst+utf8.RuneLen(r) > len(dst) { err = transform.ErrShortDst break loop } nDst += utf8.EncodeRune(dst[nDst:], r) } return nDst, nSrc, err } type gbkEncoder struct { transform.NopResetter gb18030 bool } func (e gbkEncoder) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) { r, r2, size := rune(0), rune(0), 0 for ; nSrc < len(src); nSrc += size { 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 } } // func init checks that the switch covers all tables. switch { case encode0Low <= r && r < encode0High: if r2 = rune(encode0[r-encode0Low]); r2 != 0 { goto write2 } case encode1Low <= r && r < encode1High: // Microsoft's Code Page 936 extends GBK 1.0 to encode the euro sign U+20AC // as 0x80. The HTML5 specification at http://encoding.spec.whatwg.org/#gbk // says to treat "gbk" as Code Page 936. if r == '€' { r = 0x80 goto write1 } if r2 = rune(encode1[r-encode1Low]); r2 != 0 { goto write2 } case encode2Low <= r && r < encode2High: if r2 = rune(encode2[r-encode2Low]); r2 != 0 { goto write2 } case encode3Low <= r && r < encode3High: if r2 = rune(encode3[r-encode3Low]); r2 != 0 { goto write2 } case encode4Low <= r && r < encode4High: if r2 = rune(encode4[r-encode4Low]); r2 != 0 { goto write2 } } if e.gb18030 { if r < 0x10000 { i, j := 0, len(gb18030) for i < j { h := i + (j-i)/2 if r >= rune(gb18030[h][1]) { i = h + 1 } else { j = h } } dec := &gb18030[i-1] r += rune(dec[0]) - rune(dec[1]) goto write4 } else if r < 0x110000 { r += 189000 - 0x10000 goto write4 } } err = internal.ErrASCIIReplacement break } write1: if nDst >= len(dst) { err = transform.ErrShortDst break } dst[nDst] = uint8(r) nDst++ continue write2: if nDst+2 > len(dst) { err = transform.ErrShortDst break } dst[nDst+0] = uint8(r2 >> 8) dst[nDst+1] = uint8(r2) nDst += 2 continue write4: if nDst+4 > len(dst) { err = transform.ErrShortDst break } dst[nDst+3] = uint8(r%10 + 0x30) r /= 10 dst[nDst+2] = uint8(r%126 + 0x81) r /= 126 dst[nDst+1] = uint8(r%10 + 0x30) r /= 10 dst[nDst+0] = uint8(r + 0x81) nDst += 4 continue } return nDst, nSrc, err } func init() { // Check that the hard-coded encode switch covers all tables. if numEncodeTables != 5 { panic("bad numEncodeTables") } }