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author | 2025-03-09 17:47:56 +0100 | |
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committer | 2025-03-10 01:59:49 +0100 | |
commit | 3ac1ee16f377d31a0fb80c8dae28b6239ac4229e (patch) | |
tree | f61faa581feaaeaba2542b9f2b8234a590684413 /vendor/github.com/klauspost/compress/zstd/encoder_options.go | |
parent | [chore] update URLs to forked source (diff) | |
download | gotosocial-3ac1ee16f377d31a0fb80c8dae28b6239ac4229e.tar.xz |
[chore] remove vendor
Diffstat (limited to 'vendor/github.com/klauspost/compress/zstd/encoder_options.go')
-rw-r--r-- | vendor/github.com/klauspost/compress/zstd/encoder_options.go | 339 |
1 files changed, 0 insertions, 339 deletions
diff --git a/vendor/github.com/klauspost/compress/zstd/encoder_options.go b/vendor/github.com/klauspost/compress/zstd/encoder_options.go deleted file mode 100644 index 20671dcb9..000000000 --- a/vendor/github.com/klauspost/compress/zstd/encoder_options.go +++ /dev/null @@ -1,339 +0,0 @@ -package zstd - -import ( - "errors" - "fmt" - "math" - "math/bits" - "runtime" - "strings" -) - -// EOption is an option for creating a encoder. -type EOption func(*encoderOptions) error - -// options retains accumulated state of multiple options. -type encoderOptions struct { - concurrent int - level EncoderLevel - single *bool - pad int - blockSize int - windowSize int - crc bool - fullZero bool - noEntropy bool - allLitEntropy bool - customWindow bool - customALEntropy bool - customBlockSize bool - lowMem bool - dict *dict -} - -func (o *encoderOptions) setDefault() { - *o = encoderOptions{ - concurrent: runtime.GOMAXPROCS(0), - crc: true, - single: nil, - blockSize: maxCompressedBlockSize, - windowSize: 8 << 20, - level: SpeedDefault, - allLitEntropy: false, - lowMem: false, - } -} - -// encoder returns an encoder with the selected options. -func (o encoderOptions) encoder() encoder { - switch o.level { - case SpeedFastest: - if o.dict != nil { - return &fastEncoderDict{fastEncoder: fastEncoder{fastBase: fastBase{maxMatchOff: int32(o.windowSize), bufferReset: math.MaxInt32 - int32(o.windowSize*2), lowMem: o.lowMem}}} - } - return &fastEncoder{fastBase: fastBase{maxMatchOff: int32(o.windowSize), bufferReset: math.MaxInt32 - int32(o.windowSize*2), lowMem: o.lowMem}} - - case SpeedDefault: - if o.dict != nil { - return &doubleFastEncoderDict{fastEncoderDict: fastEncoderDict{fastEncoder: fastEncoder{fastBase: fastBase{maxMatchOff: int32(o.windowSize), bufferReset: math.MaxInt32 - int32(o.windowSize*2), lowMem: o.lowMem}}}} - } - return &doubleFastEncoder{fastEncoder: fastEncoder{fastBase: fastBase{maxMatchOff: int32(o.windowSize), bufferReset: math.MaxInt32 - int32(o.windowSize*2), lowMem: o.lowMem}}} - case SpeedBetterCompression: - if o.dict != nil { - return &betterFastEncoderDict{betterFastEncoder: betterFastEncoder{fastBase: fastBase{maxMatchOff: int32(o.windowSize), bufferReset: math.MaxInt32 - int32(o.windowSize*2), lowMem: o.lowMem}}} - } - return &betterFastEncoder{fastBase: fastBase{maxMatchOff: int32(o.windowSize), bufferReset: math.MaxInt32 - int32(o.windowSize*2), lowMem: o.lowMem}} - case SpeedBestCompression: - return &bestFastEncoder{fastBase: fastBase{maxMatchOff: int32(o.windowSize), bufferReset: math.MaxInt32 - int32(o.windowSize*2), lowMem: o.lowMem}} - } - panic("unknown compression level") -} - -// WithEncoderCRC will add CRC value to output. -// Output will be 4 bytes larger. -func WithEncoderCRC(b bool) EOption { - return func(o *encoderOptions) error { o.crc = b; return nil } -} - -// WithEncoderConcurrency will set the concurrency, -// meaning the maximum number of encoders to run concurrently. -// The value supplied must be at least 1. -// For streams, setting a value of 1 will disable async compression. -// By default this will be set to GOMAXPROCS. -func WithEncoderConcurrency(n int) EOption { - return func(o *encoderOptions) error { - if n <= 0 { - return fmt.Errorf("concurrency must be at least 1") - } - o.concurrent = n - return nil - } -} - -// WithWindowSize will set the maximum allowed back-reference distance. -// The value must be a power of two between MinWindowSize and MaxWindowSize. -// A larger value will enable better compression but allocate more memory and, -// for above-default values, take considerably longer. -// The default value is determined by the compression level and max 8MB. -func WithWindowSize(n int) EOption { - return func(o *encoderOptions) error { - switch { - case n < MinWindowSize: - return fmt.Errorf("window size must be at least %d", MinWindowSize) - case n > MaxWindowSize: - return fmt.Errorf("window size must be at most %d", MaxWindowSize) - case (n & (n - 1)) != 0: - return errors.New("window size must be a power of 2") - } - - o.windowSize = n - o.customWindow = true - if o.blockSize > o.windowSize { - o.blockSize = o.windowSize - o.customBlockSize = true - } - return nil - } -} - -// WithEncoderPadding will add padding to all output so the size will be a multiple of n. -// This can be used to obfuscate the exact output size or make blocks of a certain size. -// The contents will be a skippable frame, so it will be invisible by the decoder. -// n must be > 0 and <= 1GB, 1<<30 bytes. -// The padded area will be filled with data from crypto/rand.Reader. -// If `EncodeAll` is used with data already in the destination, the total size will be multiple of this. -func WithEncoderPadding(n int) EOption { - return func(o *encoderOptions) error { - if n <= 0 { - return fmt.Errorf("padding must be at least 1") - } - // No need to waste our time. - if n == 1 { - n = 0 - } - if n > 1<<30 { - return fmt.Errorf("padding must less than 1GB (1<<30 bytes) ") - } - o.pad = n - return nil - } -} - -// EncoderLevel predefines encoder compression levels. -// Only use the constants made available, since the actual mapping -// of these values are very likely to change and your compression could change -// unpredictably when upgrading the library. -type EncoderLevel int - -const ( - speedNotSet EncoderLevel = iota - - // SpeedFastest will choose the fastest reasonable compression. - // This is roughly equivalent to the fastest Zstandard mode. - SpeedFastest - - // SpeedDefault is the default "pretty fast" compression option. - // This is roughly equivalent to the default Zstandard mode (level 3). - SpeedDefault - - // SpeedBetterCompression will yield better compression than the default. - // Currently it is about zstd level 7-8 with ~ 2x-3x the default CPU usage. - // By using this, notice that CPU usage may go up in the future. - SpeedBetterCompression - - // SpeedBestCompression will choose the best available compression option. - // This will offer the best compression no matter the CPU cost. - SpeedBestCompression - - // speedLast should be kept as the last actual compression option. - // The is not for external usage, but is used to keep track of the valid options. - speedLast -) - -// EncoderLevelFromString will convert a string representation of an encoding level back -// to a compression level. The compare is not case sensitive. -// If the string wasn't recognized, (false, SpeedDefault) will be returned. -func EncoderLevelFromString(s string) (bool, EncoderLevel) { - for l := speedNotSet + 1; l < speedLast; l++ { - if strings.EqualFold(s, l.String()) { - return true, l - } - } - return false, SpeedDefault -} - -// EncoderLevelFromZstd will return an encoder level that closest matches the compression -// ratio of a specific zstd compression level. -// Many input values will provide the same compression level. -func EncoderLevelFromZstd(level int) EncoderLevel { - switch { - case level < 3: - return SpeedFastest - case level >= 3 && level < 6: - return SpeedDefault - case level >= 6 && level < 10: - return SpeedBetterCompression - default: - return SpeedBestCompression - } -} - -// String provides a string representation of the compression level. -func (e EncoderLevel) String() string { - switch e { - case SpeedFastest: - return "fastest" - case SpeedDefault: - return "default" - case SpeedBetterCompression: - return "better" - case SpeedBestCompression: - return "best" - default: - return "invalid" - } -} - -// WithEncoderLevel specifies a predefined compression level. -func WithEncoderLevel(l EncoderLevel) EOption { - return func(o *encoderOptions) error { - switch { - case l <= speedNotSet || l >= speedLast: - return fmt.Errorf("unknown encoder level") - } - o.level = l - if !o.customWindow { - switch o.level { - case SpeedFastest: - o.windowSize = 4 << 20 - if !o.customBlockSize { - o.blockSize = 1 << 16 - } - case SpeedDefault: - o.windowSize = 8 << 20 - case SpeedBetterCompression: - o.windowSize = 8 << 20 - case SpeedBestCompression: - o.windowSize = 8 << 20 - } - } - if !o.customALEntropy { - o.allLitEntropy = l > SpeedDefault - } - - return nil - } -} - -// WithZeroFrames will encode 0 length input as full frames. -// This can be needed for compatibility with zstandard usage, -// but is not needed for this package. -func WithZeroFrames(b bool) EOption { - return func(o *encoderOptions) error { - o.fullZero = b - return nil - } -} - -// WithAllLitEntropyCompression will apply entropy compression if no matches are found. -// Disabling this will skip incompressible data faster, but in cases with no matches but -// skewed character distribution compression is lost. -// Default value depends on the compression level selected. -func WithAllLitEntropyCompression(b bool) EOption { - return func(o *encoderOptions) error { - o.customALEntropy = true - o.allLitEntropy = b - return nil - } -} - -// WithNoEntropyCompression will always skip entropy compression of literals. -// This can be useful if content has matches, but unlikely to benefit from entropy -// compression. Usually the slight speed improvement is not worth enabling this. -func WithNoEntropyCompression(b bool) EOption { - return func(o *encoderOptions) error { - o.noEntropy = b - return nil - } -} - -// WithSingleSegment will set the "single segment" flag when EncodeAll is used. -// If this flag is set, data must be regenerated within a single continuous memory segment. -// In this case, Window_Descriptor byte is skipped, but Frame_Content_Size is necessarily present. -// As a consequence, the decoder must allocate a memory segment of size equal or larger than size of your content. -// In order to preserve the decoder from unreasonable memory requirements, -// a decoder is allowed to reject a compressed frame which requests a memory size beyond decoder's authorized range. -// For broader compatibility, decoders are recommended to support memory sizes of at least 8 MB. -// This is only a recommendation, each decoder is free to support higher or lower limits, depending on local limitations. -// If this is not specified, block encodes will automatically choose this based on the input size and the window size. -// This setting has no effect on streamed encodes. -func WithSingleSegment(b bool) EOption { - return func(o *encoderOptions) error { - o.single = &b - return nil - } -} - -// WithLowerEncoderMem will trade in some memory cases trade less memory usage for -// slower encoding speed. -// This will not change the window size which is the primary function for reducing -// memory usage. See WithWindowSize. -func WithLowerEncoderMem(b bool) EOption { - return func(o *encoderOptions) error { - o.lowMem = b - return nil - } -} - -// WithEncoderDict allows to register a dictionary that will be used for the encode. -// -// The slice dict must be in the [dictionary format] produced by -// "zstd --train" from the Zstandard reference implementation. -// -// The encoder *may* choose to use no dictionary instead for certain payloads. -// -// [dictionary format]: https://github.com/facebook/zstd/blob/dev/doc/zstd_compression_format.md#dictionary-format -func WithEncoderDict(dict []byte) EOption { - return func(o *encoderOptions) error { - d, err := loadDict(dict) - if err != nil { - return err - } - o.dict = d - return nil - } -} - -// WithEncoderDictRaw registers a dictionary that may be used by the encoder. -// -// The slice content may contain arbitrary data. It will be used as an initial -// history. -func WithEncoderDictRaw(id uint32, content []byte) EOption { - return func(o *encoderOptions) error { - if bits.UintSize > 32 && uint(len(content)) > dictMaxLength { - return fmt.Errorf("dictionary of size %d > 2GiB too large", len(content)) - } - o.dict = &dict{id: id, content: content, offsets: [3]int{1, 4, 8}} - return nil - } -} |