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author | dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com> | 2020-12-23 09:17:35 +0000 |
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committer | Daniel J Walsh <dwalsh@redhat.com> | 2020-12-23 04:29:57 -0500 |
commit | 057faea5c185d24cda40d310b0a80763ee46f4cc (patch) | |
tree | 148844953c6a27c11313175c7c9cd6625152a371 /vendor/github.com/klauspost/compress/zstd/decodeheader.go | |
parent | 07663f74c48d11732a3330248f837d5abf86fe9c (diff) | |
download | podman-057faea5c185d24cda40d310b0a80763ee46f4cc.tar.gz podman-057faea5c185d24cda40d310b0a80763ee46f4cc.tar.bz2 podman-057faea5c185d24cda40d310b0a80763ee46f4cc.zip |
Bump github.com/containers/storage from 1.24.3 to 1.24.4
Bumps [github.com/containers/storage](https://github.com/containers/storage) from 1.24.3 to 1.24.4.
- [Release notes](https://github.com/containers/storage/releases)
- [Changelog](https://github.com/containers/storage/blob/master/docs/containers-storage-changes.md)
- [Commits](https://github.com/containers/storage/compare/v1.24.3...v1.24.4)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>
Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>
Diffstat (limited to 'vendor/github.com/klauspost/compress/zstd/decodeheader.go')
-rw-r--r-- | vendor/github.com/klauspost/compress/zstd/decodeheader.go | 202 |
1 files changed, 202 insertions, 0 deletions
diff --git a/vendor/github.com/klauspost/compress/zstd/decodeheader.go b/vendor/github.com/klauspost/compress/zstd/decodeheader.go new file mode 100644 index 000000000..87896c5ea --- /dev/null +++ b/vendor/github.com/klauspost/compress/zstd/decodeheader.go @@ -0,0 +1,202 @@ +// Copyright 2020+ Klaus Post. All rights reserved. +// License information can be found in the LICENSE file. + +package zstd + +import ( + "bytes" + "errors" + "io" +) + +// HeaderMaxSize is the maximum size of a Frame and Block Header. +// If less is sent to Header.Decode it *may* still contain enough information. +const HeaderMaxSize = 14 + 3 + +// Header contains information about the first frame and block within that. +type Header struct { + // Window Size the window of data to keep while decoding. + // Will only be set if HasFCS is false. + WindowSize uint64 + + // Frame content size. + // Expected size of the entire frame. + FrameContentSize uint64 + + // Dictionary ID. + // If 0, no dictionary. + DictionaryID uint32 + + // First block information. + FirstBlock struct { + // OK will be set if first block could be decoded. + OK bool + + // Is this the last block of a frame? + Last bool + + // Is the data compressed? + // If true CompressedSize will be populated. + // Unfortunately DecompressedSize cannot be determined + // without decoding the blocks. + Compressed bool + + // DecompressedSize is the expected decompressed size of the block. + // Will be 0 if it cannot be determined. + DecompressedSize int + + // CompressedSize of the data in the block. + // Does not include the block header. + // Will be equal to DecompressedSize if not Compressed. + CompressedSize int + } + + // Skippable will be true if the frame is meant to be skipped. + // No other information will be populated. + Skippable bool + + // If set there is a checksum present for the block content. + HasCheckSum bool + + // If this is true FrameContentSize will have a valid value + HasFCS bool + + SingleSegment bool +} + +// Decode the header from the beginning of the stream. +// This will decode the frame header and the first block header if enough bytes are provided. +// It is recommended to provide at least HeaderMaxSize bytes. +// If the frame header cannot be read an error will be returned. +// If there isn't enough input, io.ErrUnexpectedEOF is returned. +// The FirstBlock.OK will indicate if enough information was available to decode the first block header. +func (h *Header) Decode(in []byte) error { + if len(in) < 4 { + return io.ErrUnexpectedEOF + } + b, in := in[:4], in[4:] + if !bytes.Equal(b, frameMagic) { + if !bytes.Equal(b[1:4], skippableFrameMagic) || b[0]&0xf0 != 0x50 { + return ErrMagicMismatch + } + *h = Header{Skippable: true} + return nil + } + if len(in) < 1 { + return io.ErrUnexpectedEOF + } + + // Clear output + *h = Header{} + fhd, in := in[0], in[1:] + h.SingleSegment = fhd&(1<<5) != 0 + h.HasCheckSum = fhd&(1<<2) != 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 + if !h.SingleSegment { + if len(in) < 1 { + return io.ErrUnexpectedEOF + } + var wd byte + wd, in = in[0], in[1:] + windowLog := 10 + (wd >> 3) + windowBase := uint64(1) << windowLog + windowAdd := (windowBase / 8) * uint64(wd&0x7) + h.WindowSize = windowBase + windowAdd + } + + // Read Dictionary_ID + // https://github.com/facebook/zstd/blob/dev/doc/zstd_compression_format.md#dictionary_id + if size := fhd & 3; size != 0 { + if size == 3 { + size = 4 + } + if len(in) < int(size) { + return io.ErrUnexpectedEOF + } + b, in = in[:size], in[size:] + if b == nil { + return io.ErrUnexpectedEOF + } + switch size { + case 1: + h.DictionaryID = uint32(b[0]) + case 2: + h.DictionaryID = uint32(b[0]) | (uint32(b[1]) << 8) + case 4: + h.DictionaryID = uint32(b[0]) | (uint32(b[1]) << 8) | (uint32(b[2]) << 16) | (uint32(b[3]) << 24) + } + } + + // 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 h.SingleSegment { + fcsSize = 1 + } + default: + fcsSize = 1 << v + } + + if fcsSize > 0 { + h.HasFCS = true + if len(in) < fcsSize { + return io.ErrUnexpectedEOF + } + b, in = in[:fcsSize], in[fcsSize:] + if b == nil { + return io.ErrUnexpectedEOF + } + switch fcsSize { + case 1: + h.FrameContentSize = uint64(b[0]) + case 2: + // When FCS_Field_Size is 2, the offset of 256 is added. + h.FrameContentSize = uint64(b[0]) | (uint64(b[1]) << 8) + 256 + case 4: + h.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) + h.FrameContentSize = uint64(d1) | (uint64(d2) << 32) + } + } + + // Frame Header done, we will not fail from now on. + if len(in) < 3 { + return nil + } + tmp, in := in[:3], in[3:] + bh := uint32(tmp[0]) | (uint32(tmp[1]) << 8) | (uint32(tmp[2]) << 16) + h.FirstBlock.Last = bh&1 != 0 + blockType := blockType((bh >> 1) & 3) + // find size. + cSize := int(bh >> 3) + switch blockType { + case blockTypeReserved: + return nil + case blockTypeRLE: + h.FirstBlock.Compressed = true + h.FirstBlock.DecompressedSize = cSize + h.FirstBlock.CompressedSize = 1 + case blockTypeCompressed: + h.FirstBlock.Compressed = true + h.FirstBlock.CompressedSize = cSize + case blockTypeRaw: + h.FirstBlock.DecompressedSize = cSize + h.FirstBlock.CompressedSize = cSize + default: + panic("Invalid block type") + } + + h.FirstBlock.OK = true + return nil +} |