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Diffstat (limited to 'vendor/github.com/klauspost/compress/zstd/bytereader.go')
-rw-r--r--vendor/github.com/klauspost/compress/zstd/bytereader.go74
1 files changed, 74 insertions, 0 deletions
diff --git a/vendor/github.com/klauspost/compress/zstd/bytereader.go b/vendor/github.com/klauspost/compress/zstd/bytereader.go
new file mode 100644
index 000000000..dc4378b64
--- /dev/null
+++ b/vendor/github.com/klauspost/compress/zstd/bytereader.go
@@ -0,0 +1,74 @@
+// 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
+
+// byteReader provides a byte reader that reads
+// little endian values from a byte stream.
+// The input stream is manually advanced.
+// The reader performs no bounds checks.
+type byteReader struct {
+ b []byte
+ off int
+}
+
+// init will initialize the reader and set the input.
+func (b *byteReader) init(in []byte) {
+ b.b = in
+ b.off = 0
+}
+
+// advance the stream b n bytes.
+func (b *byteReader) advance(n uint) {
+ b.off += int(n)
+}
+
+// overread returns whether we have advanced too far.
+func (b *byteReader) overread() bool {
+ return b.off > len(b.b)
+}
+
+// Int32 returns a little endian int32 starting at current offset.
+func (b byteReader) Int32() int32 {
+ b2 := b.b[b.off : b.off+4 : b.off+4]
+ v3 := int32(b2[3])
+ v2 := int32(b2[2])
+ v1 := int32(b2[1])
+ v0 := int32(b2[0])
+ return v0 | (v1 << 8) | (v2 << 16) | (v3 << 24)
+}
+
+// Uint8 returns the next byte
+func (b *byteReader) Uint8() uint8 {
+ v := b.b[b.off]
+ return v
+}
+
+// Uint32 returns a little endian uint32 starting at current offset.
+func (b byteReader) Uint32() uint32 {
+ if r := b.remain(); r < 4 {
+ // Very rare
+ v := uint32(0)
+ for i := 1; i <= r; i++ {
+ v = (v << 8) | uint32(b.b[len(b.b)-i])
+ }
+ return v
+ }
+ b2 := b.b[b.off : b.off+4 : b.off+4]
+ v3 := uint32(b2[3])
+ v2 := uint32(b2[2])
+ v1 := uint32(b2[1])
+ v0 := uint32(b2[0])
+ return v0 | (v1 << 8) | (v2 << 16) | (v3 << 24)
+}
+
+// unread returns the unread portion of the input.
+func (b byteReader) unread() []byte {
+ return b.b[b.off:]
+}
+
+// remain will return the number of bytes remaining.
+func (b byteReader) remain() int {
+ return len(b.b) - b.off
+}