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Diffstat (limited to 'vendor/github.com/klauspost/compress/zstd/bytebuf.go')
-rw-r--r--vendor/github.com/klauspost/compress/zstd/bytebuf.go121
1 files changed, 121 insertions, 0 deletions
diff --git a/vendor/github.com/klauspost/compress/zstd/bytebuf.go b/vendor/github.com/klauspost/compress/zstd/bytebuf.go
new file mode 100644
index 000000000..4a8460476
--- /dev/null
+++ b/vendor/github.com/klauspost/compress/zstd/bytebuf.go
@@ -0,0 +1,121 @@
+// 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 (
+ "fmt"
+ "io"
+ "io/ioutil"
+)
+
+type byteBuffer interface {
+ // Read up to 8 bytes.
+ // Returns nil if no more input is available.
+ readSmall(n int) []byte
+
+ // Read >8 bytes.
+ // MAY use the destination slice.
+ readBig(n int, dst []byte) ([]byte, error)
+
+ // Read a single byte.
+ readByte() (byte, error)
+
+ // Skip n bytes.
+ skipN(n int) error
+}
+
+// in-memory buffer
+type byteBuf []byte
+
+func (b *byteBuf) readSmall(n int) []byte {
+ if debug && n > 8 {
+ panic(fmt.Errorf("small read > 8 (%d). use readBig", n))
+ }
+ bb := *b
+ if len(bb) < n {
+ return nil
+ }
+ r := bb[:n]
+ *b = bb[n:]
+ return r
+}
+
+func (b *byteBuf) readBig(n int, dst []byte) ([]byte, error) {
+ bb := *b
+ if len(bb) < n {
+ return nil, io.ErrUnexpectedEOF
+ }
+ r := bb[:n]
+ *b = bb[n:]
+ return r, nil
+}
+
+func (b *byteBuf) remain() []byte {
+ return *b
+}
+
+func (b *byteBuf) readByte() (byte, error) {
+ bb := *b
+ if len(bb) < 1 {
+ return 0, nil
+ }
+ r := bb[0]
+ *b = bb[1:]
+ return r, nil
+}
+
+func (b *byteBuf) skipN(n int) error {
+ bb := *b
+ if len(bb) < n {
+ return io.ErrUnexpectedEOF
+ }
+ *b = bb[n:]
+ return nil
+}
+
+// wrapper around a reader.
+type readerWrapper struct {
+ r io.Reader
+ tmp [8]byte
+}
+
+func (r *readerWrapper) readSmall(n int) []byte {
+ if debug && n > 8 {
+ panic(fmt.Errorf("small read > 8 (%d). use readBig", n))
+ }
+ n2, err := io.ReadFull(r.r, r.tmp[:n])
+ // We only really care about the actual bytes read.
+ if n2 != n {
+ if debug {
+ println("readSmall: got", n2, "want", n, "err", err)
+ }
+ return nil
+ }
+ return r.tmp[:n]
+}
+
+func (r *readerWrapper) readBig(n int, dst []byte) ([]byte, error) {
+ if cap(dst) < n {
+ dst = make([]byte, n)
+ }
+ n2, err := io.ReadFull(r.r, dst[:n])
+ return dst[:n2], err
+}
+
+func (r *readerWrapper) readByte() (byte, error) {
+ n2, err := r.r.Read(r.tmp[:1])
+ if err != nil {
+ return 0, err
+ }
+ if n2 != 1 {
+ return 0, io.ErrUnexpectedEOF
+ }
+ return r.tmp[0], nil
+}
+
+func (r *readerWrapper) skipN(n int) error {
+ _, err := io.CopyN(ioutil.Discard, r.r, int64(n))
+ return err
+}