forked from Shiloh/githaven
b6a95a8cb3
* Dropped unused codekit config * Integrated dynamic and static bindata for public * Ignore public bindata * Add a general generate make task * Integrated flexible public assets into web command * Updated vendoring, added all missiong govendor deps * Made the linter happy with the bindata and dynamic code * Moved public bindata definition to modules directory * Ignoring the new bindata path now * Updated to the new public modules import path * Updated public bindata command and drop the new prefix
97 lines
2.8 KiB
Go
97 lines
2.8 KiB
Go
// Copyright 2016 The Snappy-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.
|
|
|
|
// +build !amd64
|
|
|
|
package snappy
|
|
|
|
// decode writes the decoding of src to dst. It assumes that the varint-encoded
|
|
// length of the decompressed bytes has already been read, and that len(dst)
|
|
// equals that length.
|
|
//
|
|
// It returns 0 on success or a decodeErrCodeXxx error code on failure.
|
|
func decode(dst, src []byte) int {
|
|
var d, s, offset, length int
|
|
for s < len(src) {
|
|
switch src[s] & 0x03 {
|
|
case tagLiteral:
|
|
x := uint32(src[s] >> 2)
|
|
switch {
|
|
case x < 60:
|
|
s++
|
|
case x == 60:
|
|
s += 2
|
|
if uint(s) > uint(len(src)) { // The uint conversions catch overflow from the previous line.
|
|
return decodeErrCodeCorrupt
|
|
}
|
|
x = uint32(src[s-1])
|
|
case x == 61:
|
|
s += 3
|
|
if uint(s) > uint(len(src)) { // The uint conversions catch overflow from the previous line.
|
|
return decodeErrCodeCorrupt
|
|
}
|
|
x = uint32(src[s-2]) | uint32(src[s-1])<<8
|
|
case x == 62:
|
|
s += 4
|
|
if uint(s) > uint(len(src)) { // The uint conversions catch overflow from the previous line.
|
|
return decodeErrCodeCorrupt
|
|
}
|
|
x = uint32(src[s-3]) | uint32(src[s-2])<<8 | uint32(src[s-1])<<16
|
|
case x == 63:
|
|
s += 5
|
|
if uint(s) > uint(len(src)) { // The uint conversions catch overflow from the previous line.
|
|
return decodeErrCodeCorrupt
|
|
}
|
|
x = uint32(src[s-4]) | uint32(src[s-3])<<8 | uint32(src[s-2])<<16 | uint32(src[s-1])<<24
|
|
}
|
|
length = int(x) + 1
|
|
if length <= 0 {
|
|
return decodeErrCodeUnsupportedLiteralLength
|
|
}
|
|
if length > len(dst)-d || length > len(src)-s {
|
|
return decodeErrCodeCorrupt
|
|
}
|
|
copy(dst[d:], src[s:s+length])
|
|
d += length
|
|
s += length
|
|
continue
|
|
|
|
case tagCopy1:
|
|
s += 2
|
|
if uint(s) > uint(len(src)) { // The uint conversions catch overflow from the previous line.
|
|
return decodeErrCodeCorrupt
|
|
}
|
|
length = 4 + int(src[s-2])>>2&0x7
|
|
offset = int(src[s-2])&0xe0<<3 | int(src[s-1])
|
|
|
|
case tagCopy2:
|
|
s += 3
|
|
if uint(s) > uint(len(src)) { // The uint conversions catch overflow from the previous line.
|
|
return decodeErrCodeCorrupt
|
|
}
|
|
length = 1 + int(src[s-3])>>2
|
|
offset = int(src[s-2]) | int(src[s-1])<<8
|
|
|
|
case tagCopy4:
|
|
return decodeErrCodeUnsupportedCopy4Tag
|
|
}
|
|
|
|
if offset <= 0 || d < offset || length > len(dst)-d {
|
|
return decodeErrCodeCorrupt
|
|
}
|
|
// Copy from an earlier sub-slice of dst to a later sub-slice. Unlike
|
|
// the built-in copy function, this byte-by-byte copy always runs
|
|
// forwards, even if the slices overlap. Conceptually, this is:
|
|
//
|
|
// d += forwardCopy(dst[d:d+length], dst[d-offset:])
|
|
for end := d + length; d != end; d++ {
|
|
dst[d] = dst[d-offset]
|
|
}
|
|
}
|
|
if d != len(dst) {
|
|
return decodeErrCodeCorrupt
|
|
}
|
|
return 0
|
|
}
|