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authorDaniel J Walsh <dwalsh@redhat.com>2018-07-08 07:55:30 -0400
committerAtomic Bot <atomic-devel@projectatomic.io>2018-07-19 18:43:32 +0000
commit98703eb204923f06555605c648fc165a55214520 (patch)
treea407bae8b3489d4f9b0f0d0f228658bbfe95a38e /vendor/github.com/ulikunitz/xz/lzma/buffer.go
parentc020db8cd21cb221cfbe36b264e0ec02999596ed (diff)
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Vendor in latest code for storage,image, buildah
vendor in containers/storage vendor in containers/image vendor in projectatomic/buildah Signed-off-by: Daniel J Walsh <dwalsh@redhat.com> Closes: #1114 Approved by: mheon
Diffstat (limited to 'vendor/github.com/ulikunitz/xz/lzma/buffer.go')
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diff --git a/vendor/github.com/ulikunitz/xz/lzma/buffer.go b/vendor/github.com/ulikunitz/xz/lzma/buffer.go
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@@ -0,0 +1,171 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package lzma
+
+import (
+ "errors"
+)
+
+// buffer provides a circular buffer of bytes. If the front index equals
+// the rear index the buffer is empty. As a consequence front cannot be
+// equal rear for a full buffer. So a full buffer has a length that is
+// one byte less the the length of the data slice.
+type buffer struct {
+ data []byte
+ front int
+ rear int
+}
+
+// newBuffer creates a buffer with the given size.
+func newBuffer(size int) *buffer {
+ return &buffer{data: make([]byte, size+1)}
+}
+
+// Cap returns the capacity of the buffer.
+func (b *buffer) Cap() int {
+ return len(b.data) - 1
+}
+
+// Resets the buffer. The front and rear index are set to zero.
+func (b *buffer) Reset() {
+ b.front = 0
+ b.rear = 0
+}
+
+// Buffered returns the number of bytes buffered.
+func (b *buffer) Buffered() int {
+ delta := b.front - b.rear
+ if delta < 0 {
+ delta += len(b.data)
+ }
+ return delta
+}
+
+// Available returns the number of bytes available for writing.
+func (b *buffer) Available() int {
+ delta := b.rear - 1 - b.front
+ if delta < 0 {
+ delta += len(b.data)
+ }
+ return delta
+}
+
+// addIndex adds a non-negative integer to the index i and returns the
+// resulting index. The function takes care of wrapping the index as
+// well as potential overflow situations.
+func (b *buffer) addIndex(i int, n int) int {
+ // subtraction of len(b.data) prevents overflow
+ i += n - len(b.data)
+ if i < 0 {
+ i += len(b.data)
+ }
+ return i
+}
+
+// Read reads bytes from the buffer into p and returns the number of
+// bytes read. The function never returns an error but might return less
+// data than requested.
+func (b *buffer) Read(p []byte) (n int, err error) {
+ n, err = b.Peek(p)
+ b.rear = b.addIndex(b.rear, n)
+ return n, err
+}
+
+// Peek reads bytes from the buffer into p without changing the buffer.
+// Peek will never return an error but might return less data than
+// requested.
+func (b *buffer) Peek(p []byte) (n int, err error) {
+ m := b.Buffered()
+ n = len(p)
+ if m < n {
+ n = m
+ p = p[:n]
+ }
+ k := copy(p, b.data[b.rear:])
+ if k < n {
+ copy(p[k:], b.data)
+ }
+ return n, nil
+}
+
+// Discard skips the n next bytes to read from the buffer, returning the
+// bytes discarded.
+//
+// If Discards skips fewer than n bytes, it returns an error.
+func (b *buffer) Discard(n int) (discarded int, err error) {
+ if n < 0 {
+ return 0, errors.New("buffer.Discard: negative argument")
+ }
+ m := b.Buffered()
+ if m < n {
+ n = m
+ err = errors.New(
+ "buffer.Discard: discarded less bytes then requested")
+ }
+ b.rear = b.addIndex(b.rear, n)
+ return n, err
+}
+
+// ErrNoSpace indicates that there is insufficient space for the Write
+// operation.
+var ErrNoSpace = errors.New("insufficient space")
+
+// Write puts data into the buffer. If less bytes are written than
+// requested ErrNoSpace is returned.
+func (b *buffer) Write(p []byte) (n int, err error) {
+ m := b.Available()
+ n = len(p)
+ if m < n {
+ n = m
+ p = p[:m]
+ err = ErrNoSpace
+ }
+ k := copy(b.data[b.front:], p)
+ if k < n {
+ copy(b.data, p[k:])
+ }
+ b.front = b.addIndex(b.front, n)
+ return n, err
+}
+
+// WriteByte writes a single byte into the buffer. The error ErrNoSpace
+// is returned if no single byte is available in the buffer for writing.
+func (b *buffer) WriteByte(c byte) error {
+ if b.Available() < 1 {
+ return ErrNoSpace
+ }
+ b.data[b.front] = c
+ b.front = b.addIndex(b.front, 1)
+ return nil
+}
+
+// prefixLen returns the length of the common prefix of a and b.
+func prefixLen(a, b []byte) int {
+ if len(a) > len(b) {
+ a, b = b, a
+ }
+ for i, c := range a {
+ if b[i] != c {
+ return i
+ }
+ }
+ return len(a)
+}
+
+// matchLen returns the length of the common prefix for the given
+// distance from the rear and the byte slice p.
+func (b *buffer) matchLen(distance int, p []byte) int {
+ var n int
+ i := b.rear - distance
+ if i < 0 {
+ if n = prefixLen(p, b.data[len(b.data)+i:]); n < -i {
+ return n
+ }
+ p = p[n:]
+ i = 0
+ }
+ n += prefixLen(p, b.data[i:])
+ return n
+}