From 404aeae4545d2426c089a5f8d5e82dae56f5212b Mon Sep 17 00:00:00 2001 From: Rutger Broekhoff Date: Fri, 29 Dec 2023 21:31:53 +0100 Subject: Make Nix builds work --- vendor/github.com/klauspost/compress/s2/decode.go | 437 ++++++++++++++++++++++ 1 file changed, 437 insertions(+) create mode 100644 vendor/github.com/klauspost/compress/s2/decode.go (limited to 'vendor/github.com/klauspost/compress/s2/decode.go') diff --git a/vendor/github.com/klauspost/compress/s2/decode.go b/vendor/github.com/klauspost/compress/s2/decode.go new file mode 100644 index 0000000..6c7feaf --- /dev/null +++ b/vendor/github.com/klauspost/compress/s2/decode.go @@ -0,0 +1,437 @@ +// Copyright 2011 The Snappy-Go Authors. All rights reserved. +// Copyright (c) 2019 Klaus Post. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package s2 + +import ( + "encoding/binary" + "errors" + "fmt" + "strconv" +) + +var ( + // ErrCorrupt reports that the input is invalid. + ErrCorrupt = errors.New("s2: corrupt input") + // ErrCRC reports that the input failed CRC validation (streams only) + ErrCRC = errors.New("s2: corrupt input, crc mismatch") + // ErrTooLarge reports that the uncompressed length is too large. + ErrTooLarge = errors.New("s2: decoded block is too large") + // ErrUnsupported reports that the input isn't supported. + ErrUnsupported = errors.New("s2: unsupported input") +) + +// DecodedLen returns the length of the decoded block. +func DecodedLen(src []byte) (int, error) { + v, _, err := decodedLen(src) + return v, err +} + +// decodedLen returns the length of the decoded block and the number of bytes +// that the length header occupied. +func decodedLen(src []byte) (blockLen, headerLen int, err error) { + v, n := binary.Uvarint(src) + if n <= 0 || v > 0xffffffff { + return 0, 0, ErrCorrupt + } + + const wordSize = 32 << (^uint(0) >> 32 & 1) + if wordSize == 32 && v > 0x7fffffff { + return 0, 0, ErrTooLarge + } + return int(v), n, nil +} + +const ( + decodeErrCodeCorrupt = 1 +) + +// Decode returns the decoded form of src. The returned slice may be a sub- +// slice of dst if dst was large enough to hold the entire decoded block. +// Otherwise, a newly allocated slice will be returned. +// +// The dst and src must not overlap. It is valid to pass a nil dst. +func Decode(dst, src []byte) ([]byte, error) { + dLen, s, err := decodedLen(src) + if err != nil { + return nil, err + } + if dLen <= cap(dst) { + dst = dst[:dLen] + } else { + dst = make([]byte, dLen) + } + if s2Decode(dst, src[s:]) != 0 { + return nil, ErrCorrupt + } + return dst, nil +} + +// s2DecodeDict 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 s2DecodeDict(dst, src []byte, dict *Dict) int { + if dict == nil { + return s2Decode(dst, src) + } + const debug = false + const debugErrs = debug + + if debug { + fmt.Println("Starting decode, dst len:", len(dst)) + } + var d, s, length int + offset := len(dict.dict) - dict.repeat + + // 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) + switch { + case x < 60: + s++ + case x == 60: + 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 + 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 + 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 + } + length = int(x) + 1 + if debug { + fmt.Println("literals, length:", length, "d-after:", d+length) + } + if length > len(dst)-d || length > len(src)-s || (strconv.IntSize == 32 && length <= 0) { + if debugErrs { + fmt.Println("corrupt literal: length:", length, "d-left:", len(dst)-d, "src-left:", len(src)-s) + } + return decodeErrCodeCorrupt + } + + copy(dst[d:], src[s:s+length]) + d += length + s += length + continue + + case tagCopy1: + s += 2 + 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) ") + } + // keep last offset + switch length { + case 5: + length = int(src[s]) + 4 + s += 1 + case 6: + in := src[s : s+2] + length = int(uint32(in[0])|(uint32(in[1])<<8)) + (1 << 8) + s += 2 + case 7: + in := src[s : s+3] + length = int((uint32(in[2])<<16)|(uint32(in[1])<<8)|uint32(in[0])) + (1 << 16) + s += 3 + default: // 0-> 4 + } + } else { + offset = toffset + } + 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 + + 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 + } + + if offset <= 0 || length > len(dst)-d { + if debugErrs { + fmt.Println("match error; offset:", offset, "length:", length, "dst-left:", len(dst)-d) + } + return decodeErrCodeCorrupt + } + + // copy from dict + if d < offset { + if d > MaxDictSrcOffset { + if debugErrs { + fmt.Println("dict after", MaxDictSrcOffset, "d:", d, "offset:", offset, "length:", length) + } + return decodeErrCodeCorrupt + } + startOff := len(dict.dict) - offset + d + if startOff < 0 || startOff+length > len(dict.dict) { + if debugErrs { + fmt.Printf("offset (%d) + length (%d) bigger than dict (%d)\n", offset, length, len(dict.dict)) + } + return decodeErrCodeCorrupt + } + if debug { + fmt.Println("dict copy, length:", length, "offset:", offset, "d-after:", d+length, "dict start offset:", startOff) + } + copy(dst[d:d+length], dict.dict[startOff:]) + d += length + continue + } + + if debug { + fmt.Println("copy, length:", length, "offset:", offset, "d-after:", d+length) + } + + // Copy from an earlier sub-slice of dst to a later sub-slice. + // If no overlap, use the built-in copy: + if offset > length { + copy(dst[d:d+length], dst[d-offset:]) + d += length + continue + } + + // 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:]) + // + // We align the slices into a and b and show the compiler they are the same size. + // This allows the loop to run without bounds checks. + a := dst[d : d+length] + b := dst[d-offset:] + b = b[:len(a)] + for i := range a { + a[i] = b[i] + } + d += length + } + + // Remaining with extra checks... + 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. + if debugErrs { + fmt.Println("src went oob") + } + 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. + if debugErrs { + fmt.Println("src went oob") + } + 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. + if debugErrs { + fmt.Println("src went oob") + } + 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. + if debugErrs { + fmt.Println("src went oob") + } + 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 > len(dst)-d || length > len(src)-s || (strconv.IntSize == 32 && length <= 0) { + if debugErrs { + fmt.Println("corrupt literal: length:", length, "d-left:", len(dst)-d, "src-left:", len(src)-s) + } + return decodeErrCodeCorrupt + } + if debug { + fmt.Println("literals, length:", length, "d-after:", d+length) + } + + 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. + if debugErrs { + fmt.Println("src went oob") + } + return decodeErrCodeCorrupt + } + length = int(src[s-2]) >> 2 & 0x7 + toffset := int(uint32(src[s-2])&0xe0<<3 | uint32(src[s-1])) + if toffset == 0 { + if debug { + fmt.Print("(repeat) ") + } + // keep last offset + switch length { + case 5: + s += 1 + if uint(s) > uint(len(src)) { // The uint conversions catch overflow from the previous line. + if debugErrs { + fmt.Println("src went oob") + } + return decodeErrCodeCorrupt + } + length = int(uint32(src[s-1])) + 4 + case 6: + s += 2 + if uint(s) > uint(len(src)) { // The uint conversions catch overflow from the previous line. + if debugErrs { + fmt.Println("src went oob") + } + return decodeErrCodeCorrupt + } + length = int(uint32(src[s-2])|(uint32(src[s-1])<<8)) + (1 << 8) + case 7: + s += 3 + if uint(s) > uint(len(src)) { // The uint conversions catch overflow from the previous line. + if debugErrs { + fmt.Println("src went oob") + } + return decodeErrCodeCorrupt + } + length = int(uint32(src[s-3])|(uint32(src[s-2])<<8)|(uint32(src[s-1])<<16)) + (1 << 16) + default: // 0-> 4 + } + } else { + offset = toffset + } + length += 4 + case tagCopy2: + s += 3 + if uint(s) > uint(len(src)) { // The uint conversions catch overflow from the previous line. + if debugErrs { + fmt.Println("src went oob") + } + return decodeErrCodeCorrupt + } + length = 1 + int(src[s-3])>>2 + offset = int(uint32(src[s-2]) | uint32(src[s-1])<<8) + + case tagCopy4: + s += 5 + if uint(s) > uint(len(src)) { // The uint conversions catch overflow from the previous line. + if debugErrs { + fmt.Println("src went oob") + } + return decodeErrCodeCorrupt + } + 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 || length > len(dst)-d { + if debugErrs { + fmt.Println("match error; offset:", offset, "length:", length, "dst-left:", len(dst)-d) + } + return decodeErrCodeCorrupt + } + + // copy from dict + if d < offset { + if d > MaxDictSrcOffset { + if debugErrs { + fmt.Println("dict after", MaxDictSrcOffset, "d:", d, "offset:", offset, "length:", length) + } + return decodeErrCodeCorrupt + } + rOff := len(dict.dict) - (offset - d) + if debug { + fmt.Println("starting dict entry from dict offset", len(dict.dict)-rOff) + } + if rOff+length > len(dict.dict) { + if debugErrs { + fmt.Println("err: END offset", rOff+length, "bigger than dict", len(dict.dict), "dict offset:", rOff, "length:", length) + } + return decodeErrCodeCorrupt + } + if rOff < 0 { + if debugErrs { + fmt.Println("err: START offset", rOff, "less than 0", len(dict.dict), "dict offset:", rOff, "length:", length) + } + return decodeErrCodeCorrupt + } + copy(dst[d:d+length], dict.dict[rOff:]) + d += length + continue + } + + if debug { + fmt.Println("copy, length:", length, "offset:", offset, "d-after:", d+length) + } + + // Copy from an earlier sub-slice of dst to a later sub-slice. + // If no overlap, use the built-in copy: + if offset > length { + copy(dst[d:d+length], dst[d-offset:]) + d += length + continue + } + + // 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:]) + // + // We align the slices into a and b and show the compiler they are the same size. + // This allows the loop to run without bounds checks. + a := dst[d : d+length] + b := dst[d-offset:] + b = b[:len(a)] + for i := range a { + a[i] = b[i] + } + d += length + } + + if d != len(dst) { + if debugErrs { + fmt.Println("wanted length", len(dst), "got", d) + } + return decodeErrCodeCorrupt + } + return 0 +} -- cgit v1.2.3