diff options
Diffstat (limited to 'src/pkg/encoding/git85/git.go')
| -rw-r--r-- | src/pkg/encoding/git85/git.go | 277 | 
1 files changed, 0 insertions, 277 deletions
| diff --git a/src/pkg/encoding/git85/git.go b/src/pkg/encoding/git85/git.go deleted file mode 100644 index 6bb74f46c..000000000 --- a/src/pkg/encoding/git85/git.go +++ /dev/null @@ -1,277 +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 git85 implements the radix 85 data encoding -// used in the Git version control system. -package git85 - -import ( -	"bytes" -	"io" -	"os" -	"strconv" -) - -type CorruptInputError int64 - -func (e CorruptInputError) String() string { -	return "illegal git85 data at input byte " + strconv.Itoa64(int64(e)) -} - -const encode = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz!#$%&()*+-;<=>?@^_`{|}~" - -// The decodings are 1+ the actual value, so that the -// default zero value can be used to mean "not valid". -var decode = [256]uint8{ -	'0': 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, -	'A': 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, -	24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, -	'a': 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, -	50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, -	'!': 63, -	'#': 64, 65, 66, 67, -	'(': 68, 69, 70, 71, -	'-': 72, -	';': 73, -	'<': 74, 75, 76, 77, -	'@': 78, -	'^': 79, 80, 81, -	'{': 82, 83, 84, 85, -} - -// Encode encodes src into EncodedLen(len(src)) -// bytes of dst.  As a convenience, it returns the number -// of bytes written to dst, but this value is always EncodedLen(len(src)). -// Encode implements the radix 85 encoding used in the -// Git version control tool. -// -// The encoding splits src into chunks of at most 52 bytes -// and encodes each chunk on its own line. -func Encode(dst, src []byte) int { -	ndst := 0 -	for len(src) > 0 { -		n := len(src) -		if n > 52 { -			n = 52 -		} -		if n <= 27 { -			dst[ndst] = byte('A' + n - 1) -		} else { -			dst[ndst] = byte('a' + n - 26 - 1) -		} -		ndst++ -		for i := 0; i < n; i += 4 { -			var v uint32 -			for j := 0; j < 4 && i+j < n; j++ { -				v |= uint32(src[i+j]) << uint(24-j*8) -			} -			for j := 4; j >= 0; j-- { -				dst[ndst+j] = encode[v%85] -				v /= 85 -			} -			ndst += 5 -		} -		dst[ndst] = '\n' -		ndst++ -		src = src[n:] -	} -	return ndst -} - -// EncodedLen returns the length of an encoding of n source bytes. -func EncodedLen(n int) int { -	if n == 0 { -		return 0 -	} -	// 5 bytes per 4 bytes of input, rounded up. -	// 2 extra bytes for each line of 52 src bytes, rounded up. -	return (n+3)/4*5 + (n+51)/52*2 -} - -var newline = []byte{'\n'} - -// Decode decodes src into at most MaxDecodedLen(len(src)) -// bytes, returning the actual number of bytes written to dst. -// -// If Decode encounters invalid input, it returns a CorruptInputError. -// -func Decode(dst, src []byte) (n int, err os.Error) { -	ndst := 0 -	nsrc := 0 -	for nsrc < len(src) { -		var l int -		switch ch := int(src[nsrc]); { -		case 'A' <= ch && ch <= 'Z': -			l = ch - 'A' + 1 -		case 'a' <= ch && ch <= 'z': -			l = ch - 'a' + 26 + 1 -		default: -			return ndst, CorruptInputError(nsrc) -		} -		if nsrc+1+l > len(src) { -			return ndst, CorruptInputError(nsrc) -		} -		el := (l + 3) / 4 * 5 // encoded len -		if nsrc+1+el+1 > len(src) || src[nsrc+1+el] != '\n' { -			return ndst, CorruptInputError(nsrc) -		} -		line := src[nsrc+1 : nsrc+1+el] -		for i := 0; i < el; i += 5 { -			var v uint32 -			for j := 0; j < 5; j++ { -				ch := decode[line[i+j]] -				if ch == 0 { -					return ndst, CorruptInputError(nsrc + 1 + i + j) -				} -				v = v*85 + uint32(ch-1) -			} -			for j := 0; j < 4; j++ { -				dst[ndst] = byte(v >> 24) -				v <<= 8 -				ndst++ -			} -		} -		// Last fragment may have run too far (but there was room in dst). -		// Back up. -		if l%4 != 0 { -			ndst -= 4 - l%4 -		} -		nsrc += 1 + el + 1 -	} -	return ndst, nil -} - -func MaxDecodedLen(n int) int { return n / 5 * 4 } - -// NewEncoder returns a new Git base85 stream encoder.  Data written to -// the returned writer will be encoded and then written to w. -// The Git encoding operates on 52-byte blocks; when finished -// writing, the caller must Close the returned encoder to flush any -// partially written blocks. -func NewEncoder(w io.Writer) io.WriteCloser { return &encoder{w: w} } - -type encoder struct { -	w    io.Writer -	err  os.Error -	buf  [52]byte -	nbuf int -	out  [1024]byte -	nout int -} - -func (e *encoder) Write(p []byte) (n int, err os.Error) { -	if e.err != nil { -		return 0, e.err -	} - -	// Leading fringe. -	if e.nbuf > 0 { -		var i int -		for i = 0; i < len(p) && e.nbuf < 52; i++ { -			e.buf[e.nbuf] = p[i] -			e.nbuf++ -		} -		n += i -		p = p[i:] -		if e.nbuf < 52 { -			return -		} -		nout := Encode(e.out[0:], e.buf[0:]) -		if _, e.err = e.w.Write(e.out[0:nout]); e.err != nil { -			return n, e.err -		} -		e.nbuf = 0 -	} - -	// Large interior chunks. -	for len(p) >= 52 { -		nn := len(e.out) / (1 + 52/4*5 + 1) * 52 -		if nn > len(p) { -			nn = len(p) / 52 * 52 -		} -		if nn > 0 { -			nout := Encode(e.out[0:], p[0:nn]) -			if _, e.err = e.w.Write(e.out[0:nout]); e.err != nil { -				return n, e.err -			} -		} -		n += nn -		p = p[nn:] -	} - -	// Trailing fringe. -	for i := 0; i < len(p); i++ { -		e.buf[i] = p[i] -	} -	e.nbuf = len(p) -	n += len(p) -	return -} - -func (e *encoder) Close() os.Error { -	// If there's anything left in the buffer, flush it out -	if e.err == nil && e.nbuf > 0 { -		nout := Encode(e.out[0:], e.buf[0:e.nbuf]) -		e.nbuf = 0 -		_, e.err = e.w.Write(e.out[0:nout]) -	} -	return e.err -} - -// NewDecoder returns a new Git base85 stream decoder. -func NewDecoder(r io.Reader) io.Reader { return &decoder{r: r} } - -type decoder struct { -	r       io.Reader -	err     os.Error -	readErr os.Error -	buf     [1024]byte -	nbuf    int -	out     []byte -	outbuf  [1024]byte -	off     int64 -} - -func (d *decoder) Read(p []byte) (n int, err os.Error) { -	if len(p) == 0 { -		return 0, nil -	} - -	for { -		// Copy leftover output from last decode. -		if len(d.out) > 0 { -			n = copy(p, d.out) -			d.out = d.out[n:] -			return -		} - -		// Out of decoded output.  Check errors. -		if d.err != nil { -			return 0, d.err -		} -		if d.readErr != nil { -			d.err = d.readErr -			return 0, d.err -		} - -		// Read and decode more input. -		var nn int -		nn, d.readErr = d.r.Read(d.buf[d.nbuf:]) -		d.nbuf += nn - -		// Send complete lines to Decode. -		nl := bytes.LastIndex(d.buf[0:d.nbuf], newline) -		if nl < 0 { -			continue -		} -		nn, d.err = Decode(d.outbuf[0:], d.buf[0:nl+1]) -		if e, ok := d.err.(CorruptInputError); ok { -			d.err = CorruptInputError(int64(e) + d.off) -		} -		d.out = d.outbuf[0:nn] -		d.nbuf = copy(d.buf[0:], d.buf[nl+1:d.nbuf]) -		d.off += int64(nl + 1) -	} -	panic("unreachable") -} | 
