Move modules/gzip to gitea.com/macaron/gzip (#9058)
* Move modules/gzip to gitea.com/macaron/gzip * Fix vendor
This commit is contained in:
Lunny Xiao
GitHub
parent
ba4e8f221b
commit
9ff6312627
54 changed files with 2972 additions and 5163 deletions
544
vendor/github.com/klauspost/compress/flate/huffman_bit_writer.go
generated
vendored
544
vendor/github.com/klauspost/compress/flate/huffman_bit_writer.go
generated
vendored
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@ -35,7 +35,7 @@ const (
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)
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// The number of extra bits needed by length code X - LENGTH_CODES_START.
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var lengthExtraBits = []int8{
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var lengthExtraBits = [32]int8{
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/* 257 */ 0, 0, 0,
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/* 260 */ 0, 0, 0, 0, 0, 1, 1, 1, 1, 2,
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/* 270 */ 2, 2, 2, 3, 3, 3, 3, 4, 4, 4,
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@ -43,14 +43,14 @@ var lengthExtraBits = []int8{
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}
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// The length indicated by length code X - LENGTH_CODES_START.
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var lengthBase = []uint32{
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var lengthBase = [32]uint8{
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0, 1, 2, 3, 4, 5, 6, 7, 8, 10,
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12, 14, 16, 20, 24, 28, 32, 40, 48, 56,
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64, 80, 96, 112, 128, 160, 192, 224, 255,
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}
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// offset code word extra bits.
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var offsetExtraBits = []int8{
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var offsetExtraBits = [64]int8{
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0, 0, 0, 0, 1, 1, 2, 2, 3, 3,
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4, 4, 5, 5, 6, 6, 7, 7, 8, 8,
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9, 9, 10, 10, 11, 11, 12, 12, 13, 13,
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@ -58,7 +58,7 @@ var offsetExtraBits = []int8{
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14, 14, 15, 15, 16, 16, 17, 17, 18, 18, 19, 19, 20, 20,
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}
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var offsetBase = []uint32{
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var offsetBase = [64]uint32{
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/* normal deflate */
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0x000000, 0x000001, 0x000002, 0x000003, 0x000004,
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0x000006, 0x000008, 0x00000c, 0x000010, 0x000018,
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@ -85,26 +85,48 @@ type huffmanBitWriter struct {
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// Data waiting to be written is bytes[0:nbytes]
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// and then the low nbits of bits.
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bits uint64
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nbits uint
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bytes [bufferSize]byte
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codegenFreq [codegenCodeCount]int32
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nbytes int
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literalFreq []int32
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offsetFreq []int32
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codegen []uint8
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nbits uint16
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nbytes uint8
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literalEncoding *huffmanEncoder
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offsetEncoding *huffmanEncoder
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codegenEncoding *huffmanEncoder
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err error
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lastHeader int
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// Set between 0 (reused block can be up to 2x the size)
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logReusePenalty uint
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lastHuffMan bool
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bytes [256]byte
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literalFreq [lengthCodesStart + 32]uint16
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offsetFreq [32]uint16
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codegenFreq [codegenCodeCount]uint16
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// codegen must have an extra space for the final symbol.
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codegen [literalCount + offsetCodeCount + 1]uint8
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}
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// Huffman reuse.
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//
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// The huffmanBitWriter supports reusing huffman tables and thereby combining block sections.
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//
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// This is controlled by several variables:
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//
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// If lastHeader is non-zero the Huffman table can be reused.
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// This also indicates that a Huffman table has been generated that can output all
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// possible symbols.
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// It also indicates that an EOB has not yet been emitted, so if a new tabel is generated
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// an EOB with the previous table must be written.
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//
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// If lastHuffMan is set, a table for outputting literals has been generated and offsets are invalid.
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//
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// An incoming block estimates the output size of a new table using a 'fresh' by calculating the
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// optimal size and adding a penalty in 'logReusePenalty'.
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// A Huffman table is not optimal, which is why we add a penalty, and generating a new table
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// is slower both for compression and decompression.
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func newHuffmanBitWriter(w io.Writer) *huffmanBitWriter {
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return &huffmanBitWriter{
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writer: w,
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literalFreq: make([]int32, maxNumLit),
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offsetFreq: make([]int32, offsetCodeCount),
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codegen: make([]uint8, maxNumLit+offsetCodeCount+1),
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literalEncoding: newHuffmanEncoder(maxNumLit),
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literalEncoding: newHuffmanEncoder(literalCount),
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codegenEncoding: newHuffmanEncoder(codegenCodeCount),
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offsetEncoding: newHuffmanEncoder(offsetCodeCount),
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}
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@ -113,7 +135,42 @@ func newHuffmanBitWriter(w io.Writer) *huffmanBitWriter {
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func (w *huffmanBitWriter) reset(writer io.Writer) {
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w.writer = writer
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w.bits, w.nbits, w.nbytes, w.err = 0, 0, 0, nil
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w.bytes = [bufferSize]byte{}
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w.bytes = [256]byte{}
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w.lastHeader = 0
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w.lastHuffMan = false
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}
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func (w *huffmanBitWriter) canReuse(t *tokens) (offsets, lits bool) {
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offsets, lits = true, true
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a := t.offHist[:offsetCodeCount]
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b := w.offsetFreq[:len(a)]
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for i := range a {
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if b[i] == 0 && a[i] != 0 {
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offsets = false
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break
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}
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}
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a = t.extraHist[:literalCount-256]
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b = w.literalFreq[256:literalCount]
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b = b[:len(a)]
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for i := range a {
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if b[i] == 0 && a[i] != 0 {
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lits = false
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break
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}
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}
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if lits {
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a = t.litHist[:]
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b = w.literalFreq[:len(a)]
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for i := range a {
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if b[i] == 0 && a[i] != 0 {
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lits = false
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break
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}
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}
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}
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return
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}
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func (w *huffmanBitWriter) flush() {
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@ -144,30 +201,11 @@ func (w *huffmanBitWriter) write(b []byte) {
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_, w.err = w.writer.Write(b)
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}
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func (w *huffmanBitWriter) writeBits(b int32, nb uint) {
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if w.err != nil {
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return
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}
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w.bits |= uint64(b) << w.nbits
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func (w *huffmanBitWriter) writeBits(b int32, nb uint16) {
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w.bits |= uint64(b) << (w.nbits & 63)
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w.nbits += nb
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if w.nbits >= 48 {
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bits := w.bits
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w.bits >>= 48
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w.nbits -= 48
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n := w.nbytes
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bytes := w.bytes[n : n+6]
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bytes[0] = byte(bits)
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bytes[1] = byte(bits >> 8)
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bytes[2] = byte(bits >> 16)
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bytes[3] = byte(bits >> 24)
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bytes[4] = byte(bits >> 32)
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bytes[5] = byte(bits >> 40)
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n += 6
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if n >= bufferFlushSize {
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w.write(w.bytes[:n])
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n = 0
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}
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w.nbytes = n
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w.writeOutBits()
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}
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}
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@ -213,7 +251,7 @@ func (w *huffmanBitWriter) generateCodegen(numLiterals int, numOffsets int, litE
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// a copy of the frequencies, and as the place where we put the result.
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// This is fine because the output is always shorter than the input used
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// so far.
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codegen := w.codegen // cache
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codegen := w.codegen[:] // cache
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// Copy the concatenated code sizes to codegen. Put a marker at the end.
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cgnl := codegen[:numLiterals]
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for i := range cgnl {
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@ -292,30 +330,54 @@ func (w *huffmanBitWriter) generateCodegen(numLiterals int, numOffsets int, litE
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codegen[outIndex] = badCode
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}
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// dynamicSize returns the size of dynamically encoded data in bits.
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func (w *huffmanBitWriter) dynamicSize(litEnc, offEnc *huffmanEncoder, extraBits int) (size, numCodegens int) {
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func (w *huffmanBitWriter) codegens() int {
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numCodegens := len(w.codegenFreq)
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for numCodegens > 4 && w.codegenFreq[codegenOrder[numCodegens-1]] == 0 {
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numCodegens--
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}
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return numCodegens
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}
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func (w *huffmanBitWriter) headerSize() (size, numCodegens int) {
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numCodegens = len(w.codegenFreq)
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for numCodegens > 4 && w.codegenFreq[codegenOrder[numCodegens-1]] == 0 {
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numCodegens--
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}
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header := 3 + 5 + 5 + 4 + (3 * numCodegens) +
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return 3 + 5 + 5 + 4 + (3 * numCodegens) +
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w.codegenEncoding.bitLength(w.codegenFreq[:]) +
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int(w.codegenFreq[16])*2 +
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int(w.codegenFreq[17])*3 +
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int(w.codegenFreq[18])*7
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size = header +
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litEnc.bitLength(w.literalFreq) +
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offEnc.bitLength(w.offsetFreq) +
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extraBits
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int(w.codegenFreq[18])*7, numCodegens
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}
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// dynamicSize returns the size of dynamically encoded data in bits.
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func (w *huffmanBitWriter) dynamicSize(litEnc, offEnc *huffmanEncoder, extraBits int) (size, numCodegens int) {
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header, numCodegens := w.headerSize()
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size = header +
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litEnc.bitLength(w.literalFreq[:]) +
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offEnc.bitLength(w.offsetFreq[:]) +
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extraBits
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return size, numCodegens
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}
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// extraBitSize will return the number of bits that will be written
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// as "extra" bits on matches.
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func (w *huffmanBitWriter) extraBitSize() int {
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total := 0
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for i, n := range w.literalFreq[257:literalCount] {
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total += int(n) * int(lengthExtraBits[i&31])
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}
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for i, n := range w.offsetFreq[:offsetCodeCount] {
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total += int(n) * int(offsetExtraBits[i&31])
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}
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return total
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}
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// fixedSize returns the size of dynamically encoded data in bits.
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func (w *huffmanBitWriter) fixedSize(extraBits int) int {
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return 3 +
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fixedLiteralEncoding.bitLength(w.literalFreq) +
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fixedOffsetEncoding.bitLength(w.offsetFreq) +
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fixedLiteralEncoding.bitLength(w.literalFreq[:]) +
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fixedOffsetEncoding.bitLength(w.offsetFreq[:]) +
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extraBits
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}
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@ -333,32 +395,38 @@ func (w *huffmanBitWriter) storedSize(in []byte) (int, bool) {
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}
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func (w *huffmanBitWriter) writeCode(c hcode) {
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if w.err != nil {
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return
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}
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// The function does not get inlined if we "& 63" the shift.
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w.bits |= uint64(c.code) << w.nbits
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w.nbits += uint(c.len)
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w.nbits += c.len
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if w.nbits >= 48 {
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bits := w.bits
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w.bits >>= 48
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w.nbits -= 48
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n := w.nbytes
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bytes := w.bytes[n : n+6]
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bytes[0] = byte(bits)
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bytes[1] = byte(bits >> 8)
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bytes[2] = byte(bits >> 16)
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bytes[3] = byte(bits >> 24)
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bytes[4] = byte(bits >> 32)
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bytes[5] = byte(bits >> 40)
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n += 6
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if n >= bufferFlushSize {
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w.write(w.bytes[:n])
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n = 0
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}
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w.nbytes = n
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w.writeOutBits()
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}
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}
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// writeOutBits will write bits to the buffer.
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func (w *huffmanBitWriter) writeOutBits() {
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bits := w.bits
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w.bits >>= 48
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w.nbits -= 48
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n := w.nbytes
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w.bytes[n] = byte(bits)
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w.bytes[n+1] = byte(bits >> 8)
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w.bytes[n+2] = byte(bits >> 16)
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w.bytes[n+3] = byte(bits >> 24)
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w.bytes[n+4] = byte(bits >> 32)
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w.bytes[n+5] = byte(bits >> 40)
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n += 6
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if n >= bufferFlushSize {
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if w.err != nil {
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n = 0
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return
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}
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w.write(w.bytes[:n])
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n = 0
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}
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w.nbytes = n
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}
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// Write the header of a dynamic Huffman block to the output stream.
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//
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// numLiterals The number of literals specified in codegen
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@ -412,6 +480,11 @@ func (w *huffmanBitWriter) writeStoredHeader(length int, isEof bool) {
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if w.err != nil {
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return
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}
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if w.lastHeader > 0 {
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// We owe an EOB
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w.writeCode(w.literalEncoding.codes[endBlockMarker])
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w.lastHeader = 0
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}
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var flag int32
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if isEof {
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flag = 1
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@ -426,6 +499,12 @@ func (w *huffmanBitWriter) writeFixedHeader(isEof bool) {
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if w.err != nil {
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return
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}
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if w.lastHeader > 0 {
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// We owe an EOB
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w.writeCode(w.literalEncoding.codes[endBlockMarker])
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w.lastHeader = 0
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}
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// Indicate that we are a fixed Huffman block
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var value int32 = 2
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if isEof {
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@ -439,29 +518,23 @@ func (w *huffmanBitWriter) writeFixedHeader(isEof bool) {
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// is larger than the original bytes, the data will be written as a
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// stored block.
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// If the input is nil, the tokens will always be Huffman encoded.
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func (w *huffmanBitWriter) writeBlock(tokens []token, eof bool, input []byte) {
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func (w *huffmanBitWriter) writeBlock(tokens *tokens, eof bool, input []byte) {
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if w.err != nil {
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return
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}
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tokens = append(tokens, endBlockMarker)
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numLiterals, numOffsets := w.indexTokens(tokens)
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tokens.AddEOB()
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if w.lastHeader > 0 {
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// We owe an EOB
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w.writeCode(w.literalEncoding.codes[endBlockMarker])
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w.lastHeader = 0
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}
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numLiterals, numOffsets := w.indexTokens(tokens, false)
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w.generate(tokens)
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var extraBits int
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storedSize, storable := w.storedSize(input)
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if storable {
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// We only bother calculating the costs of the extra bits required by
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// the length of offset fields (which will be the same for both fixed
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// and dynamic encoding), if we need to compare those two encodings
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// against stored encoding.
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for lengthCode := lengthCodesStart + 8; lengthCode < numLiterals; lengthCode++ {
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// First eight length codes have extra size = 0.
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extraBits += int(w.literalFreq[lengthCode]) * int(lengthExtraBits[lengthCode-lengthCodesStart])
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}
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for offsetCode := 4; offsetCode < numOffsets; offsetCode++ {
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// First four offset codes have extra size = 0.
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extraBits += int(w.offsetFreq[offsetCode]) * int(offsetExtraBits[offsetCode])
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}
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extraBits = w.extraBitSize()
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}
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// Figure out smallest code.
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@ -500,7 +573,7 @@ func (w *huffmanBitWriter) writeBlock(tokens []token, eof bool, input []byte) {
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}
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// Write the tokens.
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w.writeTokens(tokens, literalEncoding.codes, offsetEncoding.codes)
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w.writeTokens(tokens.Slice(), literalEncoding.codes, offsetEncoding.codes)
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}
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// writeBlockDynamic encodes a block using a dynamic Huffman table.
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@ -508,57 +581,103 @@ func (w *huffmanBitWriter) writeBlock(tokens []token, eof bool, input []byte) {
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// histogram distribution.
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// If input is supplied and the compression savings are below 1/16th of the
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// input size the block is stored.
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func (w *huffmanBitWriter) writeBlockDynamic(tokens []token, eof bool, input []byte) {
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func (w *huffmanBitWriter) writeBlockDynamic(tokens *tokens, eof bool, input []byte, sync bool) {
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if w.err != nil {
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return
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}
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tokens = append(tokens, endBlockMarker)
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numLiterals, numOffsets := w.indexTokens(tokens)
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// Generate codegen and codegenFrequencies, which indicates how to encode
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// the literalEncoding and the offsetEncoding.
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w.generateCodegen(numLiterals, numOffsets, w.literalEncoding, w.offsetEncoding)
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w.codegenEncoding.generate(w.codegenFreq[:], 7)
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size, numCodegens := w.dynamicSize(w.literalEncoding, w.offsetEncoding, 0)
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// Store bytes, if we don't get a reasonable improvement.
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if ssize, storable := w.storedSize(input); storable && ssize < (size+size>>4) {
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w.writeStoredHeader(len(input), eof)
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w.writeBytes(input)
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return
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sync = sync || eof
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if sync {
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tokens.AddEOB()
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}
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// Write Huffman table.
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w.writeDynamicHeader(numLiterals, numOffsets, numCodegens, eof)
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// We cannot reuse pure huffman table.
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if w.lastHuffMan && w.lastHeader > 0 {
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// We will not try to reuse.
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w.writeCode(w.literalEncoding.codes[endBlockMarker])
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w.lastHeader = 0
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w.lastHuffMan = false
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}
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if !sync {
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tokens.Fill()
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}
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numLiterals, numOffsets := w.indexTokens(tokens, !sync)
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var size int
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// Check if we should reuse.
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if w.lastHeader > 0 {
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// Estimate size for using a new table
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newSize := w.lastHeader + tokens.EstimatedBits()
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// The estimated size is calculated as an optimal table.
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// We add a penalty to make it more realistic and re-use a bit more.
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||||
newSize += newSize >> (w.logReusePenalty & 31)
|
||||
extra := w.extraBitSize()
|
||||
reuseSize, _ := w.dynamicSize(w.literalEncoding, w.offsetEncoding, extra)
|
||||
|
||||
// Check if a new table is better.
|
||||
if newSize < reuseSize {
|
||||
// Write the EOB we owe.
|
||||
w.writeCode(w.literalEncoding.codes[endBlockMarker])
|
||||
size = newSize
|
||||
w.lastHeader = 0
|
||||
} else {
|
||||
size = reuseSize
|
||||
}
|
||||
// Check if we get a reasonable size decrease.
|
||||
if ssize, storable := w.storedSize(input); storable && ssize < (size+size>>4) {
|
||||
w.writeStoredHeader(len(input), eof)
|
||||
w.writeBytes(input)
|
||||
w.lastHeader = 0
|
||||
return
|
||||
}
|
||||
}
|
||||
|
||||
// We want a new block/table
|
||||
if w.lastHeader == 0 {
|
||||
w.generate(tokens)
|
||||
// Generate codegen and codegenFrequencies, which indicates how to encode
|
||||
// the literalEncoding and the offsetEncoding.
|
||||
w.generateCodegen(numLiterals, numOffsets, w.literalEncoding, w.offsetEncoding)
|
||||
w.codegenEncoding.generate(w.codegenFreq[:], 7)
|
||||
var numCodegens int
|
||||
size, numCodegens = w.dynamicSize(w.literalEncoding, w.offsetEncoding, w.extraBitSize())
|
||||
// Store bytes, if we don't get a reasonable improvement.
|
||||
if ssize, storable := w.storedSize(input); storable && ssize < (size+size>>4) {
|
||||
w.writeStoredHeader(len(input), eof)
|
||||
w.writeBytes(input)
|
||||
w.lastHeader = 0
|
||||
return
|
||||
}
|
||||
|
||||
// Write Huffman table.
|
||||
w.writeDynamicHeader(numLiterals, numOffsets, numCodegens, eof)
|
||||
w.lastHeader, _ = w.headerSize()
|
||||
w.lastHuffMan = false
|
||||
}
|
||||
|
||||
if sync {
|
||||
w.lastHeader = 0
|
||||
}
|
||||
// Write the tokens.
|
||||
w.writeTokens(tokens, w.literalEncoding.codes, w.offsetEncoding.codes)
|
||||
w.writeTokens(tokens.Slice(), w.literalEncoding.codes, w.offsetEncoding.codes)
|
||||
}
|
||||
|
||||
// indexTokens indexes a slice of tokens, and updates
|
||||
// literalFreq and offsetFreq, and generates literalEncoding
|
||||
// and offsetEncoding.
|
||||
// The number of literal and offset tokens is returned.
|
||||
func (w *huffmanBitWriter) indexTokens(tokens []token) (numLiterals, numOffsets int) {
|
||||
for i := range w.literalFreq {
|
||||
w.literalFreq[i] = 0
|
||||
}
|
||||
for i := range w.offsetFreq {
|
||||
w.offsetFreq[i] = 0
|
||||
}
|
||||
func (w *huffmanBitWriter) indexTokens(t *tokens, filled bool) (numLiterals, numOffsets int) {
|
||||
copy(w.literalFreq[:], t.litHist[:])
|
||||
copy(w.literalFreq[256:], t.extraHist[:])
|
||||
copy(w.offsetFreq[:], t.offHist[:offsetCodeCount])
|
||||
|
||||
for _, t := range tokens {
|
||||
if t < matchType {
|
||||
w.literalFreq[t.literal()]++
|
||||
continue
|
||||
}
|
||||
length := t.length()
|
||||
offset := t.offset()
|
||||
w.literalFreq[lengthCodesStart+lengthCode(length)]++
|
||||
w.offsetFreq[offsetCode(offset)]++
|
||||
if t.n == 0 {
|
||||
return
|
||||
}
|
||||
if filled {
|
||||
return maxNumLit, maxNumDist
|
||||
}
|
||||
|
||||
// get the number of literals
|
||||
numLiterals = len(w.literalFreq)
|
||||
for w.literalFreq[numLiterals-1] == 0 {
|
||||
|
|
@ -575,41 +694,85 @@ func (w *huffmanBitWriter) indexTokens(tokens []token) (numLiterals, numOffsets
|
|||
w.offsetFreq[0] = 1
|
||||
numOffsets = 1
|
||||
}
|
||||
w.literalEncoding.generate(w.literalFreq, 15)
|
||||
w.offsetEncoding.generate(w.offsetFreq, 15)
|
||||
return
|
||||
}
|
||||
|
||||
func (w *huffmanBitWriter) generate(t *tokens) {
|
||||
w.literalEncoding.generate(w.literalFreq[:literalCount], 15)
|
||||
w.offsetEncoding.generate(w.offsetFreq[:offsetCodeCount], 15)
|
||||
}
|
||||
|
||||
// writeTokens writes a slice of tokens to the output.
|
||||
// codes for literal and offset encoding must be supplied.
|
||||
func (w *huffmanBitWriter) writeTokens(tokens []token, leCodes, oeCodes []hcode) {
|
||||
if w.err != nil {
|
||||
return
|
||||
}
|
||||
if len(tokens) == 0 {
|
||||
return
|
||||
}
|
||||
|
||||
// Only last token should be endBlockMarker.
|
||||
var deferEOB bool
|
||||
if tokens[len(tokens)-1] == endBlockMarker {
|
||||
tokens = tokens[:len(tokens)-1]
|
||||
deferEOB = true
|
||||
}
|
||||
|
||||
// Create slices up to the next power of two to avoid bounds checks.
|
||||
lits := leCodes[:256]
|
||||
offs := oeCodes[:32]
|
||||
lengths := leCodes[lengthCodesStart:]
|
||||
lengths = lengths[:32]
|
||||
for _, t := range tokens {
|
||||
if t < matchType {
|
||||
w.writeCode(leCodes[t.literal()])
|
||||
w.writeCode(lits[t.literal()])
|
||||
continue
|
||||
}
|
||||
|
||||
// Write the length
|
||||
length := t.length()
|
||||
lengthCode := lengthCode(length)
|
||||
w.writeCode(leCodes[lengthCode+lengthCodesStart])
|
||||
extraLengthBits := uint(lengthExtraBits[lengthCode])
|
||||
if false {
|
||||
w.writeCode(lengths[lengthCode&31])
|
||||
} else {
|
||||
// inlined
|
||||
c := lengths[lengthCode&31]
|
||||
w.bits |= uint64(c.code) << (w.nbits & 63)
|
||||
w.nbits += c.len
|
||||
if w.nbits >= 48 {
|
||||
w.writeOutBits()
|
||||
}
|
||||
}
|
||||
|
||||
extraLengthBits := uint16(lengthExtraBits[lengthCode&31])
|
||||
if extraLengthBits > 0 {
|
||||
extraLength := int32(length - lengthBase[lengthCode])
|
||||
extraLength := int32(length - lengthBase[lengthCode&31])
|
||||
w.writeBits(extraLength, extraLengthBits)
|
||||
}
|
||||
// Write the offset
|
||||
offset := t.offset()
|
||||
offsetCode := offsetCode(offset)
|
||||
w.writeCode(oeCodes[offsetCode])
|
||||
extraOffsetBits := uint(offsetExtraBits[offsetCode])
|
||||
if false {
|
||||
w.writeCode(offs[offsetCode&31])
|
||||
} else {
|
||||
// inlined
|
||||
c := offs[offsetCode&31]
|
||||
w.bits |= uint64(c.code) << (w.nbits & 63)
|
||||
w.nbits += c.len
|
||||
if w.nbits >= 48 {
|
||||
w.writeOutBits()
|
||||
}
|
||||
}
|
||||
extraOffsetBits := uint16(offsetExtraBits[offsetCode&63])
|
||||
if extraOffsetBits > 0 {
|
||||
extraOffset := int32(offset - offsetBase[offsetCode])
|
||||
extraOffset := int32(offset - offsetBase[offsetCode&63])
|
||||
w.writeBits(extraOffset, extraOffsetBits)
|
||||
}
|
||||
}
|
||||
if deferEOB {
|
||||
w.writeCode(leCodes[endBlockMarker])
|
||||
}
|
||||
}
|
||||
|
||||
// huffOffset is a static offset encoder used for huffman only encoding.
|
||||
|
|
@ -620,82 +783,99 @@ func init() {
|
|||
w := newHuffmanBitWriter(nil)
|
||||
w.offsetFreq[0] = 1
|
||||
huffOffset = newHuffmanEncoder(offsetCodeCount)
|
||||
huffOffset.generate(w.offsetFreq, 15)
|
||||
huffOffset.generate(w.offsetFreq[:offsetCodeCount], 15)
|
||||
}
|
||||
|
||||
// writeBlockHuff encodes a block of bytes as either
|
||||
// Huffman encoded literals or uncompressed bytes if the
|
||||
// results only gains very little from compression.
|
||||
func (w *huffmanBitWriter) writeBlockHuff(eof bool, input []byte) {
|
||||
func (w *huffmanBitWriter) writeBlockHuff(eof bool, input []byte, sync bool) {
|
||||
if w.err != nil {
|
||||
return
|
||||
}
|
||||
|
||||
// Clear histogram
|
||||
for i := range w.literalFreq {
|
||||
for i := range w.literalFreq[:] {
|
||||
w.literalFreq[i] = 0
|
||||
}
|
||||
if !w.lastHuffMan {
|
||||
for i := range w.offsetFreq[:] {
|
||||
w.offsetFreq[i] = 0
|
||||
}
|
||||
}
|
||||
|
||||
// Add everything as literals
|
||||
histogram(input, w.literalFreq)
|
||||
|
||||
w.literalFreq[endBlockMarker] = 1
|
||||
|
||||
const numLiterals = endBlockMarker + 1
|
||||
const numOffsets = 1
|
||||
|
||||
w.literalEncoding.generate(w.literalFreq, 15)
|
||||
|
||||
// Figure out smallest code.
|
||||
// Always use dynamic Huffman or Store
|
||||
var numCodegens int
|
||||
|
||||
// Generate codegen and codegenFrequencies, which indicates how to encode
|
||||
// the literalEncoding and the offsetEncoding.
|
||||
w.generateCodegen(numLiterals, numOffsets, w.literalEncoding, huffOffset)
|
||||
w.codegenEncoding.generate(w.codegenFreq[:], 7)
|
||||
size, numCodegens := w.dynamicSize(w.literalEncoding, huffOffset, 0)
|
||||
estBits := histogramSize(input, w.literalFreq[:], !eof && !sync) + 15
|
||||
|
||||
// Store bytes, if we don't get a reasonable improvement.
|
||||
if ssize, storable := w.storedSize(input); storable && ssize < (size+size>>4) {
|
||||
ssize, storable := w.storedSize(input)
|
||||
if storable && ssize < (estBits+estBits>>4) {
|
||||
w.writeStoredHeader(len(input), eof)
|
||||
w.writeBytes(input)
|
||||
return
|
||||
}
|
||||
|
||||
// Huffman.
|
||||
w.writeDynamicHeader(numLiterals, numOffsets, numCodegens, eof)
|
||||
if w.lastHeader > 0 {
|
||||
size, _ := w.dynamicSize(w.literalEncoding, huffOffset, w.lastHeader)
|
||||
estBits += estBits >> (w.logReusePenalty)
|
||||
|
||||
if estBits < size {
|
||||
// We owe an EOB
|
||||
w.writeCode(w.literalEncoding.codes[endBlockMarker])
|
||||
w.lastHeader = 0
|
||||
}
|
||||
}
|
||||
|
||||
const numLiterals = endBlockMarker + 1
|
||||
const numOffsets = 1
|
||||
if w.lastHeader == 0 {
|
||||
w.literalFreq[endBlockMarker] = 1
|
||||
w.literalEncoding.generate(w.literalFreq[:numLiterals], 15)
|
||||
|
||||
// Generate codegen and codegenFrequencies, which indicates how to encode
|
||||
// the literalEncoding and the offsetEncoding.
|
||||
w.generateCodegen(numLiterals, numOffsets, w.literalEncoding, huffOffset)
|
||||
w.codegenEncoding.generate(w.codegenFreq[:], 7)
|
||||
numCodegens := w.codegens()
|
||||
|
||||
// Huffman.
|
||||
w.writeDynamicHeader(numLiterals, numOffsets, numCodegens, eof)
|
||||
w.lastHuffMan = true
|
||||
w.lastHeader, _ = w.headerSize()
|
||||
}
|
||||
|
||||
encoding := w.literalEncoding.codes[:257]
|
||||
n := w.nbytes
|
||||
for _, t := range input {
|
||||
// Bitwriting inlined, ~30% speedup
|
||||
c := encoding[t]
|
||||
w.bits |= uint64(c.code) << w.nbits
|
||||
w.nbits += uint(c.len)
|
||||
if w.nbits < 48 {
|
||||
continue
|
||||
w.bits |= uint64(c.code) << ((w.nbits) & 63)
|
||||
w.nbits += c.len
|
||||
if w.nbits >= 48 {
|
||||
bits := w.bits
|
||||
w.bits >>= 48
|
||||
w.nbits -= 48
|
||||
n := w.nbytes
|
||||
w.bytes[n] = byte(bits)
|
||||
w.bytes[n+1] = byte(bits >> 8)
|
||||
w.bytes[n+2] = byte(bits >> 16)
|
||||
w.bytes[n+3] = byte(bits >> 24)
|
||||
w.bytes[n+4] = byte(bits >> 32)
|
||||
w.bytes[n+5] = byte(bits >> 40)
|
||||
n += 6
|
||||
if n >= bufferFlushSize {
|
||||
if w.err != nil {
|
||||
n = 0
|
||||
return
|
||||
}
|
||||
w.write(w.bytes[:n])
|
||||
n = 0
|
||||
}
|
||||
w.nbytes = n
|
||||
}
|
||||
// Store 6 bytes
|
||||
bits := w.bits
|
||||
w.bits >>= 48
|
||||
w.nbits -= 48
|
||||
bytes := w.bytes[n : n+6]
|
||||
bytes[0] = byte(bits)
|
||||
bytes[1] = byte(bits >> 8)
|
||||
bytes[2] = byte(bits >> 16)
|
||||
bytes[3] = byte(bits >> 24)
|
||||
bytes[4] = byte(bits >> 32)
|
||||
bytes[5] = byte(bits >> 40)
|
||||
n += 6
|
||||
if n < bufferFlushSize {
|
||||
continue
|
||||
}
|
||||
w.write(w.bytes[:n])
|
||||
if w.err != nil {
|
||||
return // Return early in the event of write failures
|
||||
}
|
||||
n = 0
|
||||
}
|
||||
w.nbytes = n
|
||||
w.writeCode(encoding[endBlockMarker])
|
||||
if eof || sync {
|
||||
w.writeCode(encoding[endBlockMarker])
|
||||
w.lastHeader = 0
|
||||
w.lastHuffMan = false
|
||||
}
|
||||
}
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue