1 files changed, 102 insertions, 0 deletions
diff --git a/vendor/github.com/klauspost/compress/zstd/decoder_options.go b/vendor/github.com/klauspost/compress/zstd/decoder_options.go
new file mode 100644
index 00000000..95cc9b8b
--- /dev/null
+++ b/vendor/github.com/klauspost/compress/zstd/decoder_options.go
@@ -0,0 +1,102 @@
+// 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 (
+	"errors"
+	"runtime"
+)
+
+// DOption is an option for creating a decoder.
+type DOption func(*decoderOptions) error
+
+// options retains accumulated state of multiple options.
+type decoderOptions struct {
+	lowMem         bool
+	concurrent     int
+	maxDecodedSize uint64
+	maxWindowSize  uint64
+	dicts          []dict
+}
+
+func (o *decoderOptions) setDefault() {
+	*o = decoderOptions{
+		// use less ram: true for now, but may change.
+		lowMem:        true,
+		concurrent:    runtime.GOMAXPROCS(0),
+		maxWindowSize: MaxWindowSize,
+	}
+	o.maxDecodedSize = 1 << 63
+}
+
+// WithDecoderLowmem will set whether to use a lower amount of memory,
+// but possibly have to allocate more while running.
+func WithDecoderLowmem(b bool) DOption {
+	return func(o *decoderOptions) error { o.lowMem = b; return nil }
+}
+
+// WithDecoderConcurrency will set the concurrency,
+// meaning the maximum number of decoders to run concurrently.
+// The value supplied must be at least 1.
+// By default this will be set to GOMAXPROCS.
+func WithDecoderConcurrency(n int) DOption {
+	return func(o *decoderOptions) error {
+		if n <= 0 {
+			return errors.New("concurrency must be at least 1")
+		}
+		o.concurrent = n
+		return nil
+	}
+}
+
+// WithDecoderMaxMemory allows to set a maximum decoded size for in-memory
+// non-streaming operations or maximum window size for streaming operations.
+// This can be used to control memory usage of potentially hostile content.
+// Maximum and default is 1 << 63 bytes.
+func WithDecoderMaxMemory(n uint64) DOption {
+	return func(o *decoderOptions) error {
+		if n == 0 {
+			return errors.New("WithDecoderMaxMemory must be at least 1")
+		}
+		if n > 1<<63 {
+			return errors.New("WithDecoderMaxmemory must be less than 1 << 63")
+		}
+		o.maxDecodedSize = n
+		return nil
+	}
+}
+
+// WithDecoderDicts allows to register one or more dictionaries for the decoder.
+// If several dictionaries with the same ID is provided the last one will be used.
+func WithDecoderDicts(dicts ...[]byte) DOption {
+	return func(o *decoderOptions) error {
+		for _, b := range dicts {
+			d, err := loadDict(b)
+			if err != nil {
+				return err
+			}
+			o.dicts = append(o.dicts, *d)
+		}
+		return nil
+	}
+}
+
+// WithDecoderMaxWindow allows to set a maximum window size for decodes.
+// This allows rejecting packets that will cause big memory usage.
+// The Decoder will likely allocate more memory based on the WithDecoderLowmem setting.
+// If WithDecoderMaxMemory is set to a lower value, that will be used.
+// Default is 512MB, Maximum is ~3.75 TB as per zstandard spec.
+func WithDecoderMaxWindow(size uint64) DOption {
+	return func(o *decoderOptions) error {
+		if size < MinWindowSize {
+			return errors.New("WithMaxWindowSize must be at least 1KB, 1024 bytes")
+		}
+		if size > (1<<41)+7*(1<<38) {
+			return errors.New("WithMaxWindowSize must be less than (1<<41) + 7*(1<<38) ~ 3.75TB")
+		}
+		o.maxWindowSize = size
+		return nil
+	}
+}