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authordependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>2022-01-28 23:48:40 +0100
committerGitHub <noreply@github.com>2022-01-28 23:48:40 +0100
commit5a1fd7daddbb07b93e3611d023ea48e1991fc0c6 (patch)
treee592a99163702c4c6214c9519a7983fa58fab13c /vendor/github.com/klauspost/compress/zstd/encoder_options.go
parentac06a268096285a9f795bd19df950075a930c9d6 (diff)
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Bump github.com/SevereCloud/vksdk/v2 from 2.11.0 to 2.13.0 (#1698)
Bumps [github.com/SevereCloud/vksdk/v2](https://github.com/SevereCloud/vksdk) from 2.11.0 to 2.13.0. - [Release notes](https://github.com/SevereCloud/vksdk/releases) - [Commits](https://github.com/SevereCloud/vksdk/compare/v2.11.0...v2.13.0) --- updated-dependencies: - dependency-name: github.com/SevereCloud/vksdk/v2 dependency-type: direct:production update-type: version-update:semver-minor ... Signed-off-by: dependabot[bot] <support@github.com> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Diffstat (limited to 'vendor/github.com/klauspost/compress/zstd/encoder_options.go')
-rw-r--r--vendor/github.com/klauspost/compress/zstd/encoder_options.go312
1 files changed, 312 insertions, 0 deletions
diff --git a/vendor/github.com/klauspost/compress/zstd/encoder_options.go b/vendor/github.com/klauspost/compress/zstd/encoder_options.go
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+++ b/vendor/github.com/klauspost/compress/zstd/encoder_options.go
@@ -0,0 +1,312 @@
+package zstd
+
+import (
+ "errors"
+ "fmt"
+ "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
+ lowMem bool
+ dict *dict
+}
+
+func (o *encoderOptions) setDefault() {
+ *o = encoderOptions{
+ concurrent: runtime.GOMAXPROCS(0),
+ crc: true,
+ single: nil,
+ blockSize: 1 << 16,
+ windowSize: 8 << 20,
+ level: SpeedDefault,
+ allLitEntropy: true,
+ 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), lowMem: o.lowMem}}}
+ }
+ return &fastEncoder{fastBase: fastBase{maxMatchOff: int32(o.windowSize), lowMem: o.lowMem}}
+
+ case SpeedDefault:
+ if o.dict != nil {
+ return &doubleFastEncoderDict{fastEncoderDict: fastEncoderDict{fastEncoder: fastEncoder{fastBase: fastBase{maxMatchOff: int32(o.windowSize), lowMem: o.lowMem}}}}
+ }
+ return &doubleFastEncoder{fastEncoder: fastEncoder{fastBase: fastBase{maxMatchOff: int32(o.windowSize), lowMem: o.lowMem}}}
+ case SpeedBetterCompression:
+ if o.dict != nil {
+ return &betterFastEncoderDict{betterFastEncoder: betterFastEncoder{fastBase: fastBase{maxMatchOff: int32(o.windowSize), lowMem: o.lowMem}}}
+ }
+ return &betterFastEncoder{fastBase: fastBase{maxMatchOff: int32(o.windowSize), lowMem: o.lowMem}}
+ case SpeedBestCompression:
+ return &bestFastEncoder{fastBase: fastBase{maxMatchOff: int32(o.windowSize), 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.
+// 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.
+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
+ }
+ 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 {
+ o.pad = 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
+ case level >= 10:
+ return SpeedBestCompression
+ }
+ return SpeedDefault
+}
+
+// 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
+ case SpeedDefault:
+ o.windowSize = 8 << 20
+ case SpeedBetterCompression:
+ o.windowSize = 16 << 20
+ case SpeedBestCompression:
+ o.windowSize = 32 << 20
+ }
+ }
+ if !o.customALEntropy {
+ o.allLitEntropy = l > SpeedFastest
+ }
+
+ 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.
+// 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 encoder *may* choose to use no dictionary instead for certain payloads.
+func WithEncoderDict(dict []byte) EOption {
+ return func(o *encoderOptions) error {
+ d, err := loadDict(dict)
+ if err != nil {
+ return err
+ }
+ o.dict = d
+ return nil
+ }
+}