diff options
Diffstat (limited to 'vendor/github.com/klauspost/compress/zstd/blockenc.go')
| -rw-r--r-- | vendor/github.com/klauspost/compress/zstd/blockenc.go | 60 |
1 files changed, 47 insertions, 13 deletions
diff --git a/vendor/github.com/klauspost/compress/zstd/blockenc.go b/vendor/github.com/klauspost/compress/zstd/blockenc.go index cba24c76d..9d9151a0e 100644 --- a/vendor/github.com/klauspost/compress/zstd/blockenc.go +++ b/vendor/github.com/klauspost/compress/zstd/blockenc.go @@ -155,14 +155,17 @@ func (h *literalsHeader) setSize(regenLen int) { } // setSizes will set the size of a compressed literals section and the input length. -func (h *literalsHeader) setSizes(compLen, inLen int) { +func (h *literalsHeader) setSizes(compLen, inLen int, single bool) { compBits, inBits := bits.Len32(uint32(compLen)), bits.Len32(uint32(inLen)) // Only retain 2 bits const mask = 3 lh := uint64(*h & mask) switch { case compBits <= 10 && inBits <= 10: - lh |= (1 << 2) | (uint64(inLen) << 4) | (uint64(compLen) << (10 + 4)) | (3 << 60) + if !single { + lh |= 1 << 2 + } + lh |= (uint64(inLen) << 4) | (uint64(compLen) << (10 + 4)) | (3 << 60) if debug { const mmask = (1 << 24) - 1 n := (lh >> 4) & mmask @@ -175,8 +178,14 @@ func (h *literalsHeader) setSizes(compLen, inLen int) { } case compBits <= 14 && inBits <= 14: lh |= (2 << 2) | (uint64(inLen) << 4) | (uint64(compLen) << (14 + 4)) | (4 << 60) + if single { + panic("single stream used with more than 10 bits length.") + } case compBits <= 18 && inBits <= 18: lh |= (3 << 2) | (uint64(inLen) << 4) | (uint64(compLen) << (18 + 4)) | (5 << 60) + if single { + panic("single stream used with more than 10 bits length.") + } default: panic("internal error: block too big") } @@ -307,12 +316,30 @@ func (b *blockEnc) encodeLits() error { return nil } - // TODO: Switch to 1X when less than x bytes. - out, reUsed, err := huff0.Compress4X(b.literals, b.litEnc) - // Bail out of compression is too little. - if len(out) > (len(b.literals) - len(b.literals)>>4) { + var ( + out []byte + reUsed, single bool + err error + ) + if len(b.literals) >= 1024 { + // Use 4 Streams. + out, reUsed, err = huff0.Compress4X(b.literals, b.litEnc) + if len(out) > len(b.literals)-len(b.literals)>>4 { + // Bail out of compression is too little. + err = huff0.ErrIncompressible + } + } else if len(b.literals) > 32 { + // Use 1 stream + single = true + out, reUsed, err = huff0.Compress1X(b.literals, b.litEnc) + if len(out) > len(b.literals)-len(b.literals)>>4 { + // Bail out of compression is too little. + err = huff0.ErrIncompressible + } + } else { err = huff0.ErrIncompressible } + switch err { case huff0.ErrIncompressible: if debug { @@ -351,7 +378,7 @@ func (b *blockEnc) encodeLits() error { lh.setType(literalsBlockCompressed) } // Set sizes - lh.setSizes(len(out), len(b.literals)) + lh.setSizes(len(out), len(b.literals), single) bh.setSize(uint32(len(out) + lh.size() + 1)) // Write block headers. @@ -381,16 +408,23 @@ func (b *blockEnc) encode() error { b.output = bh.appendTo(b.output) var ( - out []byte - reUsed bool - err error + out []byte + reUsed, single bool + err error ) - if len(b.literals) > 32 { - // TODO: Switch to 1X on small blocks. + if len(b.literals) >= 1024 { + // Use 4 Streams. out, reUsed, err = huff0.Compress4X(b.literals, b.litEnc) if len(out) > len(b.literals)-len(b.literals)>>4 { err = huff0.ErrIncompressible } + } else if len(b.literals) > 32 { + // Use 1 stream + single = true + out, reUsed, err = huff0.Compress1X(b.literals, b.litEnc) + if len(out) > len(b.literals)-len(b.literals)>>4 { + err = huff0.ErrIncompressible + } } else { err = huff0.ErrIncompressible } @@ -435,7 +469,7 @@ func (b *blockEnc) encode() error { } } } - lh.setSizes(len(out), len(b.literals)) + lh.setSizes(len(out), len(b.literals), single) if debug { printf("Compressed %d literals to %d bytes", len(b.literals), len(out)) println("Adding literal header:", lh) |