diff options
Diffstat (limited to 'vendor/github.com/klauspost/compress/s2/decode_other.go')
| -rw-r--r-- | vendor/github.com/klauspost/compress/s2/decode_other.go | 47 |
1 files changed, 36 insertions, 11 deletions
diff --git a/vendor/github.com/klauspost/compress/s2/decode_other.go b/vendor/github.com/klauspost/compress/s2/decode_other.go index 1074ebd2..2cb55c2c 100644 --- a/vendor/github.com/klauspost/compress/s2/decode_other.go +++ b/vendor/github.com/klauspost/compress/s2/decode_other.go @@ -28,6 +28,9 @@ func s2Decode(dst, src []byte) int { // As long as we can read at least 5 bytes... for s < len(src)-5 { + // Removing bounds checks is SLOWER, when if doing + // in := src[s:s+5] + // Checked on Go 1.18 switch src[s] & 0x03 { case tagLiteral: x := uint32(src[s] >> 2) @@ -38,17 +41,25 @@ func s2Decode(dst, src []byte) int { s += 2 x = uint32(src[s-1]) case x == 61: + in := src[s : s+3] + x = uint32(in[1]) | uint32(in[2])<<8 s += 3 - x = uint32(src[s-2]) | uint32(src[s-1])<<8 case x == 62: + in := src[s : s+4] + // Load as 32 bit and shift down. + x = uint32(in[0]) | uint32(in[1])<<8 | uint32(in[2])<<16 | uint32(in[3])<<24 + x >>= 8 s += 4 - x = uint32(src[s-3]) | uint32(src[s-2])<<8 | uint32(src[s-1])<<16 case x == 63: + in := src[s : s+5] + x = uint32(in[1]) | uint32(in[2])<<8 | uint32(in[3])<<16 | uint32(in[4])<<24 s += 5 - 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 > len(dst)-d || length > len(src)-s || (strconv.IntSize == 32 && length <= 0) { + if debug { + fmt.Println("corrupt: lit size", length) + } return decodeErrCodeCorrupt } if debug { @@ -62,8 +73,8 @@ func s2Decode(dst, src []byte) int { case tagCopy1: s += 2 - length = int(src[s-2]) >> 2 & 0x7 toffset := int(uint32(src[s-2])&0xe0<<3 | uint32(src[s-1])) + length = int(src[s-2]) >> 2 & 0x7 if toffset == 0 { if debug { fmt.Print("(repeat) ") @@ -71,14 +82,16 @@ func s2Decode(dst, src []byte) int { // keep last offset switch length { case 5: + length = int(src[s]) + 4 s += 1 - length = int(uint32(src[s-1])) + 4 case 6: + in := src[s : s+2] + length = int(uint32(in[0])|(uint32(in[1])<<8)) + (1 << 8) s += 2 - length = int(uint32(src[s-2])|(uint32(src[s-1])<<8)) + (1 << 8) case 7: + in := src[s : s+3] + length = int((uint32(in[2])<<16)|(uint32(in[1])<<8)|uint32(in[0])) + (1 << 16) s += 3 - length = int(uint32(src[s-3])|(uint32(src[s-2])<<8)|(uint32(src[s-1])<<16)) + (1 << 16) default: // 0-> 4 } } else { @@ -86,17 +99,23 @@ func s2Decode(dst, src []byte) int { } length += 4 case tagCopy2: + in := src[s : s+3] + offset = int(uint32(in[1]) | uint32(in[2])<<8) + length = 1 + int(in[0])>>2 s += 3 - length = 1 + int(src[s-3])>>2 - offset = int(uint32(src[s-2]) | uint32(src[s-1])<<8) case tagCopy4: + in := src[s : s+5] + offset = int(uint32(in[1]) | uint32(in[2])<<8 | uint32(in[3])<<16 | uint32(in[4])<<24) + length = 1 + int(in[0])>>2 s += 5 - length = 1 + int(src[s-5])>>2 - offset = int(uint32(src[s-4]) | uint32(src[s-3])<<8 | uint32(src[s-2])<<16 | uint32(src[s-1])<<24) } if offset <= 0 || d < offset || length > len(dst)-d { + if debug { + fmt.Println("corrupt: match, length", length, "offset:", offset, "dst avail:", len(dst)-d, "dst pos:", d) + } + return decodeErrCodeCorrupt } @@ -163,6 +182,9 @@ func s2Decode(dst, src []byte) int { } length = int(x) + 1 if length > len(dst)-d || length > len(src)-s || (strconv.IntSize == 32 && length <= 0) { + if debug { + fmt.Println("corrupt: lit size", length) + } return decodeErrCodeCorrupt } if debug { @@ -229,6 +251,9 @@ func s2Decode(dst, src []byte) int { } if offset <= 0 || d < offset || length > len(dst)-d { + if debug { + fmt.Println("corrupt: match, length", length, "offset:", offset, "dst avail:", len(dst)-d, "dst pos:", d) + } return decodeErrCodeCorrupt } |