diff options
Diffstat (limited to 'vendor/github.com/klauspost/compress/flate/inflate.go')
| -rw-r--r-- | vendor/github.com/klauspost/compress/flate/inflate.go | 829 |
1 files changed, 0 insertions, 829 deletions
diff --git a/vendor/github.com/klauspost/compress/flate/inflate.go b/vendor/github.com/klauspost/compress/flate/inflate.go deleted file mode 100644 index 2f410d64f..000000000 --- a/vendor/github.com/klauspost/compress/flate/inflate.go +++ /dev/null @@ -1,829 +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 flate implements the DEFLATE compressed data format, described in -// RFC 1951. The gzip and zlib packages implement access to DEFLATE-based file -// formats. -package flate - -import ( - "bufio" - "compress/flate" - "fmt" - "io" - "math/bits" - "sync" -) - -const ( - maxCodeLen = 16 // max length of Huffman code - maxCodeLenMask = 15 // mask for max length of Huffman code - // The next three numbers come from the RFC section 3.2.7, with the - // additional proviso in section 3.2.5 which implies that distance codes - // 30 and 31 should never occur in compressed data. - maxNumLit = 286 - maxNumDist = 30 - numCodes = 19 // number of codes in Huffman meta-code - - debugDecode = false -) - -// Value of length - 3 and extra bits. -type lengthExtra struct { - length, extra uint8 -} - -var decCodeToLen = [32]lengthExtra{{length: 0x0, extra: 0x0}, {length: 0x1, extra: 0x0}, {length: 0x2, extra: 0x0}, {length: 0x3, extra: 0x0}, {length: 0x4, extra: 0x0}, {length: 0x5, extra: 0x0}, {length: 0x6, extra: 0x0}, {length: 0x7, extra: 0x0}, {length: 0x8, extra: 0x1}, {length: 0xa, extra: 0x1}, {length: 0xc, extra: 0x1}, {length: 0xe, extra: 0x1}, {length: 0x10, extra: 0x2}, {length: 0x14, extra: 0x2}, {length: 0x18, extra: 0x2}, {length: 0x1c, extra: 0x2}, {length: 0x20, extra: 0x3}, {length: 0x28, extra: 0x3}, {length: 0x30, extra: 0x3}, {length: 0x38, extra: 0x3}, {length: 0x40, extra: 0x4}, {length: 0x50, extra: 0x4}, {length: 0x60, extra: 0x4}, {length: 0x70, extra: 0x4}, {length: 0x80, extra: 0x5}, {length: 0xa0, extra: 0x5}, {length: 0xc0, extra: 0x5}, {length: 0xe0, extra: 0x5}, {length: 0xff, extra: 0x0}, {length: 0x0, extra: 0x0}, {length: 0x0, extra: 0x0}, {length: 0x0, extra: 0x0}} - -var bitMask32 = [32]uint32{ - 0, 1, 3, 7, 0xF, 0x1F, 0x3F, 0x7F, 0xFF, - 0x1FF, 0x3FF, 0x7FF, 0xFFF, 0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF, - 0x1ffff, 0x3ffff, 0x7FFFF, 0xfFFFF, 0x1fFFFF, 0x3fFFFF, 0x7fFFFF, 0xffFFFF, - 0x1ffFFFF, 0x3ffFFFF, 0x7ffFFFF, 0xfffFFFF, 0x1fffFFFF, 0x3fffFFFF, 0x7fffFFFF, -} // up to 32 bits - -// Initialize the fixedHuffmanDecoder only once upon first use. -var fixedOnce sync.Once -var fixedHuffmanDecoder huffmanDecoder - -// A CorruptInputError reports the presence of corrupt input at a given offset. -type CorruptInputError = flate.CorruptInputError - -// An InternalError reports an error in the flate code itself. -type InternalError string - -func (e InternalError) Error() string { return "flate: internal error: " + string(e) } - -// A ReadError reports an error encountered while reading input. -// -// Deprecated: No longer returned. -type ReadError = flate.ReadError - -// A WriteError reports an error encountered while writing output. -// -// Deprecated: No longer returned. -type WriteError = flate.WriteError - -// Resetter resets a ReadCloser returned by NewReader or NewReaderDict to -// to switch to a new underlying Reader. This permits reusing a ReadCloser -// instead of allocating a new one. -type Resetter interface { - // Reset discards any buffered data and resets the Resetter as if it was - // newly initialized with the given reader. - Reset(r io.Reader, dict []byte) error -} - -// The data structure for decoding Huffman tables is based on that of -// zlib. There is a lookup table of a fixed bit width (huffmanChunkBits), -// For codes smaller than the table width, there are multiple entries -// (each combination of trailing bits has the same value). For codes -// larger than the table width, the table contains a link to an overflow -// table. The width of each entry in the link table is the maximum code -// size minus the chunk width. -// -// Note that you can do a lookup in the table even without all bits -// filled. Since the extra bits are zero, and the DEFLATE Huffman codes -// have the property that shorter codes come before longer ones, the -// bit length estimate in the result is a lower bound on the actual -// number of bits. -// -// See the following: -// http://www.gzip.org/algorithm.txt - -// chunk & 15 is number of bits -// chunk >> 4 is value, including table link - -const ( - huffmanChunkBits = 9 - huffmanNumChunks = 1 << huffmanChunkBits - huffmanCountMask = 15 - huffmanValueShift = 4 -) - -type huffmanDecoder struct { - maxRead int // the maximum number of bits we can read and not overread - chunks *[huffmanNumChunks]uint16 // chunks as described above - links [][]uint16 // overflow links - linkMask uint32 // mask the width of the link table -} - -// Initialize Huffman decoding tables from array of code lengths. -// Following this function, h is guaranteed to be initialized into a complete -// tree (i.e., neither over-subscribed nor under-subscribed). The exception is a -// degenerate case where the tree has only a single symbol with length 1. Empty -// trees are permitted. -func (h *huffmanDecoder) init(lengths []int) bool { - // Sanity enables additional runtime tests during Huffman - // table construction. It's intended to be used during - // development to supplement the currently ad-hoc unit tests. - const sanity = false - - if h.chunks == nil { - h.chunks = new([huffmanNumChunks]uint16) - } - - if h.maxRead != 0 { - *h = huffmanDecoder{chunks: h.chunks, links: h.links} - } - - // Count number of codes of each length, - // compute maxRead and max length. - var count [maxCodeLen]int - var min, max int - for _, n := range lengths { - if n == 0 { - continue - } - if min == 0 || n < min { - min = n - } - if n > max { - max = n - } - count[n&maxCodeLenMask]++ - } - - // Empty tree. The decompressor.huffSym function will fail later if the tree - // is used. Technically, an empty tree is only valid for the HDIST tree and - // not the HCLEN and HLIT tree. However, a stream with an empty HCLEN tree - // is guaranteed to fail since it will attempt to use the tree to decode the - // codes for the HLIT and HDIST trees. Similarly, an empty HLIT tree is - // guaranteed to fail later since the compressed data section must be - // composed of at least one symbol (the end-of-block marker). - if max == 0 { - return true - } - - code := 0 - var nextcode [maxCodeLen]int - for i := min; i <= max; i++ { - code <<= 1 - nextcode[i&maxCodeLenMask] = code - code += count[i&maxCodeLenMask] - } - - // Check that the coding is complete (i.e., that we've - // assigned all 2-to-the-max possible bit sequences). - // Exception: To be compatible with zlib, we also need to - // accept degenerate single-code codings. See also - // TestDegenerateHuffmanCoding. - if code != 1<<uint(max) && !(code == 1 && max == 1) { - if debugDecode { - fmt.Println("coding failed, code, max:", code, max, code == 1<<uint(max), code == 1 && max == 1, "(one should be true)") - } - return false - } - - h.maxRead = min - - chunks := h.chunks[:] - for i := range chunks { - chunks[i] = 0 - } - - if max > huffmanChunkBits { - numLinks := 1 << (uint(max) - huffmanChunkBits) - h.linkMask = uint32(numLinks - 1) - - // create link tables - link := nextcode[huffmanChunkBits+1] >> 1 - if cap(h.links) < huffmanNumChunks-link { - h.links = make([][]uint16, huffmanNumChunks-link) - } else { - h.links = h.links[:huffmanNumChunks-link] - } - for j := uint(link); j < huffmanNumChunks; j++ { - reverse := int(bits.Reverse16(uint16(j))) - reverse >>= uint(16 - huffmanChunkBits) - off := j - uint(link) - if sanity && h.chunks[reverse] != 0 { - panic("impossible: overwriting existing chunk") - } - h.chunks[reverse] = uint16(off<<huffmanValueShift | (huffmanChunkBits + 1)) - if cap(h.links[off]) < numLinks { - h.links[off] = make([]uint16, numLinks) - } else { - h.links[off] = h.links[off][:numLinks] - } - } - } else { - h.links = h.links[:0] - } - - for i, n := range lengths { - if n == 0 { - continue - } - code := nextcode[n] - nextcode[n]++ - chunk := uint16(i<<huffmanValueShift | n) - reverse := int(bits.Reverse16(uint16(code))) - reverse >>= uint(16 - n) - if n <= huffmanChunkBits { - for off := reverse; off < len(h.chunks); off += 1 << uint(n) { - // We should never need to overwrite - // an existing chunk. Also, 0 is - // never a valid chunk, because the - // lower 4 "count" bits should be - // between 1 and 15. - if sanity && h.chunks[off] != 0 { - panic("impossible: overwriting existing chunk") - } - h.chunks[off] = chunk - } - } else { - j := reverse & (huffmanNumChunks - 1) - if sanity && h.chunks[j]&huffmanCountMask != huffmanChunkBits+1 { - // Longer codes should have been - // associated with a link table above. - panic("impossible: not an indirect chunk") - } - value := h.chunks[j] >> huffmanValueShift - linktab := h.links[value] - reverse >>= huffmanChunkBits - for off := reverse; off < len(linktab); off += 1 << uint(n-huffmanChunkBits) { - if sanity && linktab[off] != 0 { - panic("impossible: overwriting existing chunk") - } - linktab[off] = chunk - } - } - } - - if sanity { - // Above we've sanity checked that we never overwrote - // an existing entry. Here we additionally check that - // we filled the tables completely. - for i, chunk := range h.chunks { - if chunk == 0 { - // As an exception, in the degenerate - // single-code case, we allow odd - // chunks to be missing. - if code == 1 && i%2 == 1 { - continue - } - panic("impossible: missing chunk") - } - } - for _, linktab := range h.links { - for _, chunk := range linktab { - if chunk == 0 { - panic("impossible: missing chunk") - } - } - } - } - - return true -} - -// Reader is the actual read interface needed by NewReader. -// If the passed in io.Reader does not also have ReadByte, -// the NewReader will introduce its own buffering. -type Reader interface { - io.Reader - io.ByteReader -} - -type step uint8 - -const ( - copyData step = iota + 1 - nextBlock - huffmanBytesBuffer - huffmanBytesReader - huffmanBufioReader - huffmanStringsReader - huffmanGenericReader -) - -// Decompress state. -type decompressor struct { - // Input source. - r Reader - roffset int64 - - // Huffman decoders for literal/length, distance. - h1, h2 huffmanDecoder - - // Length arrays used to define Huffman codes. - bits *[maxNumLit + maxNumDist]int - codebits *[numCodes]int - - // Output history, buffer. - dict dictDecoder - - // Next step in the decompression, - // and decompression state. - step step - stepState int - err error - toRead []byte - hl, hd *huffmanDecoder - copyLen int - copyDist int - - // Temporary buffer (avoids repeated allocation). - buf [4]byte - - // Input bits, in top of b. - b uint32 - - nb uint - final bool -} - -func (f *decompressor) nextBlock() { - for f.nb < 1+2 { - if f.err = f.moreBits(); f.err != nil { - return - } - } - f.final = f.b&1 == 1 - f.b >>= 1 - typ := f.b & 3 - f.b >>= 2 - f.nb -= 1 + 2 - switch typ { - case 0: - f.dataBlock() - if debugDecode { - fmt.Println("stored block") - } - case 1: - // compressed, fixed Huffman tables - f.hl = &fixedHuffmanDecoder - f.hd = nil - f.huffmanBlockDecoder() - if debugDecode { - fmt.Println("predefinied huffman block") - } - case 2: - // compressed, dynamic Huffman tables - if f.err = f.readHuffman(); f.err != nil { - break - } - f.hl = &f.h1 - f.hd = &f.h2 - f.huffmanBlockDecoder() - if debugDecode { - fmt.Println("dynamic huffman block") - } - default: - // 3 is reserved. - if debugDecode { - fmt.Println("reserved data block encountered") - } - f.err = CorruptInputError(f.roffset) - } -} - -func (f *decompressor) Read(b []byte) (int, error) { - for { - if len(f.toRead) > 0 { - n := copy(b, f.toRead) - f.toRead = f.toRead[n:] - if len(f.toRead) == 0 { - return n, f.err - } - return n, nil - } - if f.err != nil { - return 0, f.err - } - - f.doStep() - - if f.err != nil && len(f.toRead) == 0 { - f.toRead = f.dict.readFlush() // Flush what's left in case of error - } - } -} - -// WriteTo implements the io.WriteTo interface for io.Copy and friends. -func (f *decompressor) WriteTo(w io.Writer) (int64, error) { - total := int64(0) - flushed := false - for { - if len(f.toRead) > 0 { - n, err := w.Write(f.toRead) - total += int64(n) - if err != nil { - f.err = err - return total, err - } - if n != len(f.toRead) { - return total, io.ErrShortWrite - } - f.toRead = f.toRead[:0] - } - if f.err != nil && flushed { - if f.err == io.EOF { - return total, nil - } - return total, f.err - } - if f.err == nil { - f.doStep() - } - if len(f.toRead) == 0 && f.err != nil && !flushed { - f.toRead = f.dict.readFlush() // Flush what's left in case of error - flushed = true - } - } -} - -func (f *decompressor) Close() error { - if f.err == io.EOF { - return nil - } - return f.err -} - -// RFC 1951 section 3.2.7. -// Compression with dynamic Huffman codes - -var codeOrder = [...]int{16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15} - -func (f *decompressor) readHuffman() error { - // HLIT[5], HDIST[5], HCLEN[4]. - for f.nb < 5+5+4 { - if err := f.moreBits(); err != nil { - return err - } - } - nlit := int(f.b&0x1F) + 257 - if nlit > maxNumLit { - if debugDecode { - fmt.Println("nlit > maxNumLit", nlit) - } - return CorruptInputError(f.roffset) - } - f.b >>= 5 - ndist := int(f.b&0x1F) + 1 - if ndist > maxNumDist { - if debugDecode { - fmt.Println("ndist > maxNumDist", ndist) - } - return CorruptInputError(f.roffset) - } - f.b >>= 5 - nclen := int(f.b&0xF) + 4 - // numCodes is 19, so nclen is always valid. - f.b >>= 4 - f.nb -= 5 + 5 + 4 - - // (HCLEN+4)*3 bits: code lengths in the magic codeOrder order. - for i := 0; i < nclen; i++ { - for f.nb < 3 { - if err := f.moreBits(); err != nil { - return err - } - } - f.codebits[codeOrder[i]] = int(f.b & 0x7) - f.b >>= 3 - f.nb -= 3 - } - for i := nclen; i < len(codeOrder); i++ { - f.codebits[codeOrder[i]] = 0 - } - if !f.h1.init(f.codebits[0:]) { - if debugDecode { - fmt.Println("init codebits failed") - } - return CorruptInputError(f.roffset) - } - - // HLIT + 257 code lengths, HDIST + 1 code lengths, - // using the code length Huffman code. - for i, n := 0, nlit+ndist; i < n; { - x, err := f.huffSym(&f.h1) - if err != nil { - return err - } - if x < 16 { - // Actual length. - f.bits[i] = x - i++ - continue - } - // Repeat previous length or zero. - var rep int - var nb uint - var b int - switch x { - default: - return InternalError("unexpected length code") - case 16: - rep = 3 - nb = 2 - if i == 0 { - if debugDecode { - fmt.Println("i==0") - } - return CorruptInputError(f.roffset) - } - b = f.bits[i-1] - case 17: - rep = 3 - nb = 3 - b = 0 - case 18: - rep = 11 - nb = 7 - b = 0 - } - for f.nb < nb { - if err := f.moreBits(); err != nil { - if debugDecode { - fmt.Println("morebits:", err) - } - return err - } - } - rep += int(f.b & uint32(1<<(nb®SizeMaskUint32)-1)) - f.b >>= nb & regSizeMaskUint32 - f.nb -= nb - if i+rep > n { - if debugDecode { - fmt.Println("i+rep > n", i, rep, n) - } - return CorruptInputError(f.roffset) - } - for j := 0; j < rep; j++ { - f.bits[i] = b - i++ - } - } - - if !f.h1.init(f.bits[0:nlit]) || !f.h2.init(f.bits[nlit:nlit+ndist]) { - if debugDecode { - fmt.Println("init2 failed") - } - return CorruptInputError(f.roffset) - } - - // As an optimization, we can initialize the maxRead bits to read at a time - // for the HLIT tree to the length of the EOB marker since we know that - // every block must terminate with one. This preserves the property that - // we never read any extra bytes after the end of the DEFLATE stream. - if f.h1.maxRead < f.bits[endBlockMarker] { - f.h1.maxRead = f.bits[endBlockMarker] - } - if !f.final { - // If not the final block, the smallest block possible is - // a predefined table, BTYPE=01, with a single EOB marker. - // This will take up 3 + 7 bits. - f.h1.maxRead += 10 - } - - return nil -} - -// Copy a single uncompressed data block from input to output. -func (f *decompressor) dataBlock() { - // Uncompressed. - // Discard current half-byte. - left := (f.nb) & 7 - f.nb -= left - f.b >>= left - - offBytes := f.nb >> 3 - // Unfilled values will be overwritten. - f.buf[0] = uint8(f.b) - f.buf[1] = uint8(f.b >> 8) - f.buf[2] = uint8(f.b >> 16) - f.buf[3] = uint8(f.b >> 24) - - f.roffset += int64(offBytes) - f.nb, f.b = 0, 0 - - // Length then ones-complement of length. - nr, err := io.ReadFull(f.r, f.buf[offBytes:4]) - f.roffset += int64(nr) - if err != nil { - f.err = noEOF(err) - return - } - n := uint16(f.buf[0]) | uint16(f.buf[1])<<8 - nn := uint16(f.buf[2]) | uint16(f.buf[3])<<8 - if nn != ^n { - if debugDecode { - ncomp := ^n - fmt.Println("uint16(nn) != uint16(^n)", nn, ncomp) - } - f.err = CorruptInputError(f.roffset) - return - } - - if n == 0 { - f.toRead = f.dict.readFlush() - f.finishBlock() - return - } - - f.copyLen = int(n) - f.copyData() -} - -// copyData copies f.copyLen bytes from the underlying reader into f.hist. -// It pauses for reads when f.hist is full. -func (f *decompressor) copyData() { - buf := f.dict.writeSlice() - if len(buf) > f.copyLen { - buf = buf[:f.copyLen] - } - - cnt, err := io.ReadFull(f.r, buf) - f.roffset += int64(cnt) - f.copyLen -= cnt - f.dict.writeMark(cnt) - if err != nil { - f.err = noEOF(err) - return - } - - if f.dict.availWrite() == 0 || f.copyLen > 0 { - f.toRead = f.dict.readFlush() - f.step = copyData - return - } - f.finishBlock() -} - -func (f *decompressor) finishBlock() { - if f.final { - if f.dict.availRead() > 0 { - f.toRead = f.dict.readFlush() - } - f.err = io.EOF - } - f.step = nextBlock -} - -func (f *decompressor) doStep() { - switch f.step { - case copyData: - f.copyData() - case nextBlock: - f.nextBlock() - case huffmanBytesBuffer: - f.huffmanBytesBuffer() - case huffmanBytesReader: - f.huffmanBytesReader() - case huffmanBufioReader: - f.huffmanBufioReader() - case huffmanStringsReader: - f.huffmanStringsReader() - case huffmanGenericReader: - f.huffmanGenericReader() - default: - panic("BUG: unexpected step state") - } -} - -// noEOF returns err, unless err == io.EOF, in which case it returns io.ErrUnexpectedEOF. -func noEOF(e error) error { - if e == io.EOF { - return io.ErrUnexpectedEOF - } - return e -} - -func (f *decompressor) moreBits() error { - c, err := f.r.ReadByte() - if err != nil { - return noEOF(err) - } - f.roffset++ - f.b |= uint32(c) << (f.nb & regSizeMaskUint32) - f.nb += 8 - return nil -} - -// Read the next Huffman-encoded symbol from f according to h. -func (f *decompressor) huffSym(h *huffmanDecoder) (int, error) { - // Since a huffmanDecoder can be empty or be composed of a degenerate tree - // with single element, huffSym must error on these two edge cases. In both - // cases, the chunks slice will be 0 for the invalid sequence, leading it - // satisfy the n == 0 check below. - n := uint(h.maxRead) - // Optimization. Compiler isn't smart enough to keep f.b,f.nb in registers, - // but is smart enough to keep local variables in registers, so use nb and b, - // inline call to moreBits and reassign b,nb back to f on return. - nb, b := f.nb, f.b - for { - for nb < n { - c, err := f.r.ReadByte() - if err != nil { - f.b = b - f.nb = nb - return 0, noEOF(err) - } - f.roffset++ - b |= uint32(c) << (nb & regSizeMaskUint32) - nb += 8 - } - chunk := h.chunks[b&(huffmanNumChunks-1)] - n = uint(chunk & huffmanCountMask) - if n > huffmanChunkBits { - chunk = h.links[chunk>>huffmanValueShift][(b>>huffmanChunkBits)&h.linkMask] - n = uint(chunk & huffmanCountMask) - } - if n <= nb { - if n == 0 { - f.b = b - f.nb = nb - if debugDecode { - fmt.Println("huffsym: n==0") - } - f.err = CorruptInputError(f.roffset) - return 0, f.err - } - f.b = b >> (n & regSizeMaskUint32) - f.nb = nb - n - return int(chunk >> huffmanValueShift), nil - } - } -} - -func makeReader(r io.Reader) Reader { - if rr, ok := r.(Reader); ok { - return rr - } - return bufio.NewReader(r) -} - -func fixedHuffmanDecoderInit() { - fixedOnce.Do(func() { - // These come from the RFC section 3.2.6. - var bits [288]int - for i := 0; i < 144; i++ { - bits[i] = 8 - } - for i := 144; i < 256; i++ { - bits[i] = 9 - } - for i := 256; i < 280; i++ { - bits[i] = 7 - } - for i := 280; i < 288; i++ { - bits[i] = 8 - } - fixedHuffmanDecoder.init(bits[:]) - }) -} - -func (f *decompressor) Reset(r io.Reader, dict []byte) error { - *f = decompressor{ - r: makeReader(r), - bits: f.bits, - codebits: f.codebits, - h1: f.h1, - h2: f.h2, - dict: f.dict, - step: nextBlock, - } - f.dict.init(maxMatchOffset, dict) - return nil -} - -// NewReader returns a new ReadCloser that can be used -// to read the uncompressed version of r. -// If r does not also implement io.ByteReader, -// the decompressor may read more data than necessary from r. -// It is the caller's responsibility to call Close on the ReadCloser -// when finished reading. -// -// The ReadCloser returned by NewReader also implements Resetter. -func NewReader(r io.Reader) io.ReadCloser { - fixedHuffmanDecoderInit() - - var f decompressor - f.r = makeReader(r) - f.bits = new([maxNumLit + maxNumDist]int) - f.codebits = new([numCodes]int) - f.step = nextBlock - f.dict.init(maxMatchOffset, nil) - return &f -} - -// NewReaderDict is like NewReader but initializes the reader -// with a preset dictionary. The returned Reader behaves as if -// the uncompressed data stream started with the given dictionary, -// which has already been read. NewReaderDict is typically used -// to read data compressed by NewWriterDict. -// -// The ReadCloser returned by NewReader also implements Resetter. -func NewReaderDict(r io.Reader, dict []byte) io.ReadCloser { - fixedHuffmanDecoderInit() - - var f decompressor - f.r = makeReader(r) - f.bits = new([maxNumLit + maxNumDist]int) - f.codebits = new([numCodes]int) - f.step = nextBlock - f.dict.init(maxMatchOffset, dict) - return &f -} |