diff options
Diffstat (limited to 'vendor/github.com/klauspost/compress/zstd/framedec.go')
| -rw-r--r-- | vendor/github.com/klauspost/compress/zstd/framedec.go | 415 |
1 files changed, 0 insertions, 415 deletions
diff --git a/vendor/github.com/klauspost/compress/zstd/framedec.go b/vendor/github.com/klauspost/compress/zstd/framedec.go deleted file mode 100644 index e47af66e7..000000000 --- a/vendor/github.com/klauspost/compress/zstd/framedec.go +++ /dev/null @@ -1,415 +0,0 @@ -// Copyright 2019+ Klaus Post. All rights reserved. -// License information can be found in the LICENSE file. -// Based on work by Yann Collet, released under BSD License. - -package zstd - -import ( - "encoding/binary" - "encoding/hex" - "errors" - "io" - - "github.com/klauspost/compress/zstd/internal/xxhash" -) - -type frameDec struct { - o decoderOptions - crc *xxhash.Digest - - WindowSize uint64 - - // Frame history passed between blocks - history history - - rawInput byteBuffer - - // Byte buffer that can be reused for small input blocks. - bBuf byteBuf - - FrameContentSize uint64 - - DictionaryID uint32 - HasCheckSum bool - SingleSegment bool -} - -const ( - // MinWindowSize is the minimum Window Size, which is 1 KB. - MinWindowSize = 1 << 10 - - // MaxWindowSize is the maximum encoder window size - // and the default decoder maximum window size. - MaxWindowSize = 1 << 29 -) - -const ( - frameMagic = "\x28\xb5\x2f\xfd" - skippableFrameMagic = "\x2a\x4d\x18" -) - -func newFrameDec(o decoderOptions) *frameDec { - if o.maxWindowSize > o.maxDecodedSize { - o.maxWindowSize = o.maxDecodedSize - } - d := frameDec{ - o: o, - } - return &d -} - -// reset will read the frame header and prepare for block decoding. -// If nothing can be read from the input, io.EOF will be returned. -// Any other error indicated that the stream contained data, but -// there was a problem. -func (d *frameDec) reset(br byteBuffer) error { - d.HasCheckSum = false - d.WindowSize = 0 - var signature [4]byte - for { - var err error - // Check if we can read more... - b, err := br.readSmall(1) - switch err { - case io.EOF, io.ErrUnexpectedEOF: - return io.EOF - case nil: - signature[0] = b[0] - default: - return err - } - // Read the rest, don't allow io.ErrUnexpectedEOF - b, err = br.readSmall(3) - switch err { - case io.EOF: - return io.EOF - case nil: - copy(signature[1:], b) - default: - return err - } - - if string(signature[1:4]) != skippableFrameMagic || signature[0]&0xf0 != 0x50 { - if debugDecoder { - println("Not skippable", hex.EncodeToString(signature[:]), hex.EncodeToString([]byte(skippableFrameMagic))) - } - // Break if not skippable frame. - break - } - // Read size to skip - b, err = br.readSmall(4) - if err != nil { - if debugDecoder { - println("Reading Frame Size", err) - } - return err - } - n := uint32(b[0]) | (uint32(b[1]) << 8) | (uint32(b[2]) << 16) | (uint32(b[3]) << 24) - println("Skipping frame with", n, "bytes.") - err = br.skipN(int64(n)) - if err != nil { - if debugDecoder { - println("Reading discarded frame", err) - } - return err - } - } - if string(signature[:]) != frameMagic { - if debugDecoder { - println("Got magic numbers: ", signature, "want:", []byte(frameMagic)) - } - return ErrMagicMismatch - } - - // Read Frame_Header_Descriptor - fhd, err := br.readByte() - if err != nil { - if debugDecoder { - println("Reading Frame_Header_Descriptor", err) - } - return err - } - d.SingleSegment = fhd&(1<<5) != 0 - - if fhd&(1<<3) != 0 { - return errors.New("reserved bit set on frame header") - } - - // Read Window_Descriptor - // https://github.com/facebook/zstd/blob/dev/doc/zstd_compression_format.md#window_descriptor - d.WindowSize = 0 - if !d.SingleSegment { - wd, err := br.readByte() - if err != nil { - if debugDecoder { - println("Reading Window_Descriptor", err) - } - return err - } - if debugDecoder { - printf("raw: %x, mantissa: %d, exponent: %d\n", wd, wd&7, wd>>3) - } - windowLog := 10 + (wd >> 3) - windowBase := uint64(1) << windowLog - windowAdd := (windowBase / 8) * uint64(wd&0x7) - d.WindowSize = windowBase + windowAdd - } - - // Read Dictionary_ID - // https://github.com/facebook/zstd/blob/dev/doc/zstd_compression_format.md#dictionary_id - d.DictionaryID = 0 - if size := fhd & 3; size != 0 { - if size == 3 { - size = 4 - } - - b, err := br.readSmall(int(size)) - if err != nil { - println("Reading Dictionary_ID", err) - return err - } - var id uint32 - switch len(b) { - case 1: - id = uint32(b[0]) - case 2: - id = uint32(b[0]) | (uint32(b[1]) << 8) - case 4: - id = uint32(b[0]) | (uint32(b[1]) << 8) | (uint32(b[2]) << 16) | (uint32(b[3]) << 24) - } - if debugDecoder { - println("Dict size", size, "ID:", id) - } - d.DictionaryID = id - } - - // Read Frame_Content_Size - // https://github.com/facebook/zstd/blob/dev/doc/zstd_compression_format.md#frame_content_size - var fcsSize int - v := fhd >> 6 - switch v { - case 0: - if d.SingleSegment { - fcsSize = 1 - } - default: - fcsSize = 1 << v - } - d.FrameContentSize = fcsUnknown - if fcsSize > 0 { - b, err := br.readSmall(fcsSize) - if err != nil { - println("Reading Frame content", err) - return err - } - switch len(b) { - case 1: - d.FrameContentSize = uint64(b[0]) - case 2: - // When FCS_Field_Size is 2, the offset of 256 is added. - d.FrameContentSize = uint64(b[0]) | (uint64(b[1]) << 8) + 256 - case 4: - d.FrameContentSize = uint64(b[0]) | (uint64(b[1]) << 8) | (uint64(b[2]) << 16) | (uint64(b[3]) << 24) - case 8: - d1 := uint32(b[0]) | (uint32(b[1]) << 8) | (uint32(b[2]) << 16) | (uint32(b[3]) << 24) - d2 := uint32(b[4]) | (uint32(b[5]) << 8) | (uint32(b[6]) << 16) | (uint32(b[7]) << 24) - d.FrameContentSize = uint64(d1) | (uint64(d2) << 32) - } - if debugDecoder { - println("Read FCS:", d.FrameContentSize) - } - } - - // Move this to shared. - d.HasCheckSum = fhd&(1<<2) != 0 - if d.HasCheckSum { - if d.crc == nil { - d.crc = xxhash.New() - } - d.crc.Reset() - } - - if d.WindowSize > d.o.maxWindowSize { - if debugDecoder { - printf("window size %d > max %d\n", d.WindowSize, d.o.maxWindowSize) - } - return ErrWindowSizeExceeded - } - - if d.WindowSize == 0 && d.SingleSegment { - // We may not need window in this case. - d.WindowSize = d.FrameContentSize - if d.WindowSize < MinWindowSize { - d.WindowSize = MinWindowSize - } - if d.WindowSize > d.o.maxDecodedSize { - if debugDecoder { - printf("window size %d > max %d\n", d.WindowSize, d.o.maxWindowSize) - } - return ErrDecoderSizeExceeded - } - } - - // The minimum Window_Size is 1 KB. - if d.WindowSize < MinWindowSize { - if debugDecoder { - println("got window size: ", d.WindowSize) - } - return ErrWindowSizeTooSmall - } - d.history.windowSize = int(d.WindowSize) - if !d.o.lowMem || d.history.windowSize < maxBlockSize { - // Alloc 2x window size if not low-mem, or window size below 2MB. - d.history.allocFrameBuffer = d.history.windowSize * 2 - } else { - if d.o.lowMem { - // Alloc with 1MB extra. - d.history.allocFrameBuffer = d.history.windowSize + maxBlockSize/2 - } else { - // Alloc with 2MB extra. - d.history.allocFrameBuffer = d.history.windowSize + maxBlockSize - } - } - - if debugDecoder { - println("Frame: Dict:", d.DictionaryID, "FrameContentSize:", d.FrameContentSize, "singleseg:", d.SingleSegment, "window:", d.WindowSize, "crc:", d.HasCheckSum) - } - - // history contains input - maybe we do something - d.rawInput = br - return nil -} - -// next will start decoding the next block from stream. -func (d *frameDec) next(block *blockDec) error { - if debugDecoder { - println("decoding new block") - } - err := block.reset(d.rawInput, d.WindowSize) - if err != nil { - println("block error:", err) - // Signal the frame decoder we have a problem. - block.sendErr(err) - return err - } - return nil -} - -// checkCRC will check the checksum, assuming the frame has one. -// Will return ErrCRCMismatch if crc check failed, otherwise nil. -func (d *frameDec) checkCRC() error { - // We can overwrite upper tmp now - buf, err := d.rawInput.readSmall(4) - if err != nil { - println("CRC missing?", err) - return err - } - - want := binary.LittleEndian.Uint32(buf[:4]) - got := uint32(d.crc.Sum64()) - - if got != want { - if debugDecoder { - printf("CRC check failed: got %08x, want %08x\n", got, want) - } - return ErrCRCMismatch - } - if debugDecoder { - printf("CRC ok %08x\n", got) - } - return nil -} - -// consumeCRC skips over the checksum, assuming the frame has one. -func (d *frameDec) consumeCRC() error { - _, err := d.rawInput.readSmall(4) - if err != nil { - println("CRC missing?", err) - } - return err -} - -// runDecoder will run the decoder for the remainder of the frame. -func (d *frameDec) runDecoder(dst []byte, dec *blockDec) ([]byte, error) { - saved := d.history.b - - // We use the history for output to avoid copying it. - d.history.b = dst - d.history.ignoreBuffer = len(dst) - // Store input length, so we only check new data. - crcStart := len(dst) - d.history.decoders.maxSyncLen = 0 - if d.o.limitToCap { - d.history.decoders.maxSyncLen = uint64(cap(dst) - len(dst)) - } - if d.FrameContentSize != fcsUnknown { - if !d.o.limitToCap || d.FrameContentSize+uint64(len(dst)) < d.history.decoders.maxSyncLen { - d.history.decoders.maxSyncLen = d.FrameContentSize + uint64(len(dst)) - } - if d.history.decoders.maxSyncLen > d.o.maxDecodedSize { - if debugDecoder { - println("maxSyncLen:", d.history.decoders.maxSyncLen, "> maxDecodedSize:", d.o.maxDecodedSize) - } - return dst, ErrDecoderSizeExceeded - } - if debugDecoder { - println("maxSyncLen:", d.history.decoders.maxSyncLen) - } - if !d.o.limitToCap && uint64(cap(dst)) < d.history.decoders.maxSyncLen { - // Alloc for output - dst2 := make([]byte, len(dst), d.history.decoders.maxSyncLen+compressedBlockOverAlloc) - copy(dst2, dst) - dst = dst2 - } - } - var err error - for { - err = dec.reset(d.rawInput, d.WindowSize) - if err != nil { - break - } - if debugDecoder { - println("next block:", dec) - } - err = dec.decodeBuf(&d.history) - if err != nil { - break - } - if uint64(len(d.history.b)-crcStart) > d.o.maxDecodedSize { - println("runDecoder: maxDecodedSize exceeded", uint64(len(d.history.b)-crcStart), ">", d.o.maxDecodedSize) - err = ErrDecoderSizeExceeded - break - } - if d.o.limitToCap && len(d.history.b) > cap(dst) { - println("runDecoder: cap exceeded", uint64(len(d.history.b)), ">", cap(dst)) - err = ErrDecoderSizeExceeded - break - } - if uint64(len(d.history.b)-crcStart) > d.FrameContentSize { - println("runDecoder: FrameContentSize exceeded", uint64(len(d.history.b)-crcStart), ">", d.FrameContentSize) - err = ErrFrameSizeExceeded - break - } - if dec.Last { - break - } - if debugDecoder { - println("runDecoder: FrameContentSize", uint64(len(d.history.b)-crcStart), "<=", d.FrameContentSize) - } - } - dst = d.history.b - if err == nil { - if d.FrameContentSize != fcsUnknown && uint64(len(d.history.b)-crcStart) != d.FrameContentSize { - err = ErrFrameSizeMismatch - } else if d.HasCheckSum { - if d.o.ignoreChecksum { - err = d.consumeCRC() - } else { - d.crc.Write(dst[crcStart:]) - err = d.checkCRC() - } - } - } - d.history.b = saved - return dst, err -} |