From bc7189b7f234cf9cef41790a2a6b1f9ceac9f518 Mon Sep 17 00:00:00 2001 From: Klaus Post Date: Wed, 4 Sep 2019 16:53:03 -0700 Subject: [PATCH] Lazy init of zstd tables. --- zstd/decoder.go | 1 + zstd/encoder.go | 1 + zstd/fse_predefined.go | 159 +++++++++++++++++++++-------------------- zstd/snappy.go | 1 + 4 files changed, 85 insertions(+), 77 deletions(-) diff --git a/zstd/decoder.go b/zstd/decoder.go index f4db3096ad..098f9bf99f 100644 --- a/zstd/decoder.go +++ b/zstd/decoder.go @@ -75,6 +75,7 @@ var ( // The Reset function can be used to initiate a new stream, which is will considerably // reduce the allocations normally caused by NewReader. func NewReader(r io.Reader, opts ...DOption) (*Decoder, error) { + initPredefined() var d Decoder d.o.setDefault() for _, o := range opts { diff --git a/zstd/encoder.go b/zstd/encoder.go index b7011be29a..c39b571196 100644 --- a/zstd/encoder.go +++ b/zstd/encoder.go @@ -59,6 +59,7 @@ type encoderState struct { // NewWriter will create a new Zstandard encoder. // If the encoder will be used for encoding blocks a nil writer can be used. func NewWriter(w io.Writer, opts ...EOption) (*Encoder, error) { + initPredefined() var e Encoder e.o.setDefault() for _, o := range opts { diff --git a/zstd/fse_predefined.go b/zstd/fse_predefined.go index 5186de8027..6c17dc17f4 100644 --- a/zstd/fse_predefined.go +++ b/zstd/fse_predefined.go @@ -7,6 +7,7 @@ package zstd import ( "fmt" "math" + "sync" ) var ( @@ -69,85 +70,89 @@ func fillBase(dst []baseOffset, base uint32, bits ...uint8) { } } -func init() { - // Literals length codes - tmp := make([]baseOffset, 36) - for i := range tmp[:16] { - tmp[i] = baseOffset{ - baseLine: uint32(i), - addBits: 0, +var predef sync.Once + +func initPredefined() { + predef.Do(func() { + // Literals length codes + tmp := make([]baseOffset, 36) + for i := range tmp[:16] { + tmp[i] = baseOffset{ + baseLine: uint32(i), + addBits: 0, + } } - } - fillBase(tmp[16:], 16, 1, 1, 1, 1, 2, 2, 3, 3, 4, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16) - symbolTableX[tableLiteralLengths] = tmp - - // Match length codes - tmp = make([]baseOffset, 53) - for i := range tmp[:32] { - tmp[i] = baseOffset{ - // The transformation adds the 3 length. - baseLine: uint32(i) + 3, - addBits: 0, - } - } - fillBase(tmp[32:], 35, 1, 1, 1, 1, 2, 2, 3, 3, 4, 4, 5, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16) - symbolTableX[tableMatchLengths] = tmp - - // Offset codes - tmp = make([]baseOffset, maxOffsetBits+1) - tmp[1] = baseOffset{ - baseLine: 1, - addBits: 1, - } - fillBase(tmp[2:], 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30) - symbolTableX[tableOffsets] = tmp - - // Fill predefined tables and transform them. - // https://github.com/facebook/zstd/blob/dev/doc/zstd_compression_format.md#default-distributions - for i := range fsePredef[:] { - f := &fsePredef[i] - switch tableIndex(i) { - case tableLiteralLengths: - // https://github.com/facebook/zstd/blob/ededcfca57366461021c922720878c81a5854a0a/lib/decompress/zstd_decompress_block.c#L243 - f.actualTableLog = 6 - copy(f.norm[:], []int16{4, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, - 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 2, 1, 1, 1, 1, 1, - -1, -1, -1, -1}) - f.symbolLen = 36 - case tableOffsets: - // https://github.com/facebook/zstd/blob/ededcfca57366461021c922720878c81a5854a0a/lib/decompress/zstd_decompress_block.c#L281 - f.actualTableLog = 5 - copy(f.norm[:], []int16{ - 1, 1, 1, 1, 1, 1, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, - 1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1}) - f.symbolLen = 29 - case tableMatchLengths: - //https://github.com/facebook/zstd/blob/ededcfca57366461021c922720878c81a5854a0a/lib/decompress/zstd_decompress_block.c#L304 - f.actualTableLog = 6 - copy(f.norm[:], []int16{ - 1, 4, 3, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, - 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, - 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, -1, -1, - -1, -1, -1, -1, -1}) - f.symbolLen = 53 + fillBase(tmp[16:], 16, 1, 1, 1, 1, 2, 2, 3, 3, 4, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16) + symbolTableX[tableLiteralLengths] = tmp + + // Match length codes + tmp = make([]baseOffset, 53) + for i := range tmp[:32] { + tmp[i] = baseOffset{ + // The transformation adds the 3 length. + baseLine: uint32(i) + 3, + addBits: 0, + } } - if err := f.buildDtable(); err != nil { - panic(fmt.Errorf("building table %v: %v", tableIndex(i), err)) + fillBase(tmp[32:], 35, 1, 1, 1, 1, 2, 2, 3, 3, 4, 4, 5, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16) + symbolTableX[tableMatchLengths] = tmp + + // Offset codes + tmp = make([]baseOffset, maxOffsetBits+1) + tmp[1] = baseOffset{ + baseLine: 1, + addBits: 1, } - if err := f.transform(symbolTableX[i]); err != nil { - panic(fmt.Errorf("building table %v: %v", tableIndex(i), err)) + fillBase(tmp[2:], 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30) + symbolTableX[tableOffsets] = tmp + + // Fill predefined tables and transform them. + // https://github.com/facebook/zstd/blob/dev/doc/zstd_compression_format.md#default-distributions + for i := range fsePredef[:] { + f := &fsePredef[i] + switch tableIndex(i) { + case tableLiteralLengths: + // https://github.com/facebook/zstd/blob/ededcfca57366461021c922720878c81a5854a0a/lib/decompress/zstd_decompress_block.c#L243 + f.actualTableLog = 6 + copy(f.norm[:], []int16{4, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, + 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 2, 1, 1, 1, 1, 1, + -1, -1, -1, -1}) + f.symbolLen = 36 + case tableOffsets: + // https://github.com/facebook/zstd/blob/ededcfca57366461021c922720878c81a5854a0a/lib/decompress/zstd_decompress_block.c#L281 + f.actualTableLog = 5 + copy(f.norm[:], []int16{ + 1, 1, 1, 1, 1, 1, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, + 1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1}) + f.symbolLen = 29 + case tableMatchLengths: + //https://github.com/facebook/zstd/blob/ededcfca57366461021c922720878c81a5854a0a/lib/decompress/zstd_decompress_block.c#L304 + f.actualTableLog = 6 + copy(f.norm[:], []int16{ + 1, 4, 3, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, + 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, + 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, -1, -1, + -1, -1, -1, -1, -1}) + f.symbolLen = 53 + } + if err := f.buildDtable(); err != nil { + panic(fmt.Errorf("building table %v: %v", tableIndex(i), err)) + } + if err := f.transform(symbolTableX[i]); err != nil { + panic(fmt.Errorf("building table %v: %v", tableIndex(i), err)) + } + f.preDefined = true + + // Create encoder as well + enc := &fsePredefEnc[i] + copy(enc.norm[:], f.norm[:]) + enc.symbolLen = f.symbolLen + enc.actualTableLog = f.actualTableLog + if err := enc.buildCTable(); err != nil { + panic(fmt.Errorf("building encoding table %v: %v", tableIndex(i), err)) + } + enc.setBits(bitTables[i]) + enc.preDefined = true } - f.preDefined = true - - // Create encoder as well - enc := &fsePredefEnc[i] - copy(enc.norm[:], f.norm[:]) - enc.symbolLen = f.symbolLen - enc.actualTableLog = f.actualTableLog - if err := enc.buildCTable(); err != nil { - panic(fmt.Errorf("building encoding table %v: %v", tableIndex(i), err)) - } - enc.setBits(bitTables[i]) - enc.preDefined = true - } + }) } diff --git a/zstd/snappy.go b/zstd/snappy.go index e9e518570e..a048818f9a 100644 --- a/zstd/snappy.go +++ b/zstd/snappy.go @@ -80,6 +80,7 @@ type SnappyConverter struct { // If any error is detected on the Snappy stream it is returned. // The number of bytes written is returned. func (r *SnappyConverter) Convert(in io.Reader, w io.Writer) (int64, error) { + initPredefined() r.err = nil r.r = in if r.block == nil {