VictoriaMetrics/vendor/github.com/klauspost/compress/zstd/zstd.go

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// Package zstd provides decompression of zstandard files.
//
// For advanced usage and examples, go to the README: https://github.com/klauspost/compress/tree/master/zstd#zstd
package zstd
import (
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"bytes"
"encoding/binary"
"errors"
"log"
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"math"
"math/bits"
)
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// enable debug printing
const debug = false
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// enable encoding debug printing
const debugEncoder = debug
// enable decoding debug printing
const debugDecoder = debug
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// Enable extra assertions.
const debugAsserts = debug || false
// print sequence details
const debugSequences = false
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// print detailed matching information
const debugMatches = false
// force encoder to use predefined tables.
const forcePreDef = false
// zstdMinMatch is the minimum zstd match length.
const zstdMinMatch = 3
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// fcsUnknown is used for unknown frame content size.
const fcsUnknown = math.MaxUint64
var (
// ErrReservedBlockType is returned when a reserved block type is found.
// Typically this indicates wrong or corrupted input.
ErrReservedBlockType = errors.New("invalid input: reserved block type encountered")
// ErrCompressedSizeTooBig is returned when a block is bigger than allowed.
// Typically this indicates wrong or corrupted input.
ErrCompressedSizeTooBig = errors.New("invalid input: compressed size too big")
// ErrBlockTooSmall is returned when a block is too small to be decoded.
// Typically returned on invalid input.
ErrBlockTooSmall = errors.New("block too small")
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// ErrUnexpectedBlockSize is returned when a block has unexpected size.
// Typically returned on invalid input.
ErrUnexpectedBlockSize = errors.New("unexpected block size")
// ErrMagicMismatch is returned when a "magic" number isn't what is expected.
// Typically this indicates wrong or corrupted input.
ErrMagicMismatch = errors.New("invalid input: magic number mismatch")
// ErrWindowSizeExceeded is returned when a reference exceeds the valid window size.
// Typically this indicates wrong or corrupted input.
ErrWindowSizeExceeded = errors.New("window size exceeded")
// ErrWindowSizeTooSmall is returned when no window size is specified.
// Typically this indicates wrong or corrupted input.
ErrWindowSizeTooSmall = errors.New("invalid input: window size was too small")
// ErrDecoderSizeExceeded is returned if decompressed size exceeds the configured limit.
ErrDecoderSizeExceeded = errors.New("decompressed size exceeds configured limit")
// ErrUnknownDictionary is returned if the dictionary ID is unknown.
ErrUnknownDictionary = errors.New("unknown dictionary")
// ErrFrameSizeExceeded is returned if the stated frame size is exceeded.
// This is only returned if SingleSegment is specified on the frame.
ErrFrameSizeExceeded = errors.New("frame size exceeded")
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// ErrFrameSizeMismatch is returned if the stated frame size does not match the expected size.
// This is only returned if SingleSegment is specified on the frame.
ErrFrameSizeMismatch = errors.New("frame size does not match size on stream")
// ErrCRCMismatch is returned if CRC mismatches.
ErrCRCMismatch = errors.New("CRC check failed")
// ErrDecoderClosed will be returned if the Decoder was used after
// Close has been called.
ErrDecoderClosed = errors.New("decoder used after Close")
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// ErrDecoderNilInput is returned when a nil Reader was provided
// and an operation other than Reset/DecodeAll/Close was attempted.
ErrDecoderNilInput = errors.New("nil input provided as reader")
)
func println(a ...interface{}) {
if debug || debugDecoder || debugEncoder {
log.Println(a...)
}
}
func printf(format string, a ...interface{}) {
if debug || debugDecoder || debugEncoder {
log.Printf(format, a...)
}
}
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// matchLen returns the maximum common prefix length of a and b.
// a must be the shortest of the two.
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func matchLen(a, b []byte) (n int) {
for ; len(a) >= 8 && len(b) >= 8; a, b = a[8:], b[8:] {
diff := binary.LittleEndian.Uint64(a) ^ binary.LittleEndian.Uint64(b)
if diff != 0 {
return n + bits.TrailingZeros64(diff)>>3
}
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n += 8
}
for i := range a {
if a[i] != b[i] {
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break
}
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n++
}
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return n
}
func load3232(b []byte, i int32) uint32 {
return binary.LittleEndian.Uint32(b[i:])
}
func load6432(b []byte, i int32) uint64 {
return binary.LittleEndian.Uint64(b[i:])
}
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type byter interface {
Bytes() []byte
Len() int
}
var _ byter = &bytes.Buffer{}