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author | Daniel J Walsh <dwalsh@redhat.com> | 2018-07-08 07:55:30 -0400 |
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committer | Atomic Bot <atomic-devel@projectatomic.io> | 2018-07-19 18:43:32 +0000 |
commit | 98703eb204923f06555605c648fc165a55214520 (patch) | |
tree | a407bae8b3489d4f9b0f0d0f228658bbfe95a38e /vendor/github.com/ulikunitz/xz/lzma/buffer.go | |
parent | c020db8cd21cb221cfbe36b264e0ec02999596ed (diff) | |
download | podman-98703eb204923f06555605c648fc165a55214520.tar.gz podman-98703eb204923f06555605c648fc165a55214520.tar.bz2 podman-98703eb204923f06555605c648fc165a55214520.zip |
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')
-rw-r--r-- | vendor/github.com/ulikunitz/xz/lzma/buffer.go | 171 |
1 files changed, 171 insertions, 0 deletions
diff --git a/vendor/github.com/ulikunitz/xz/lzma/buffer.go b/vendor/github.com/ulikunitz/xz/lzma/buffer.go new file mode 100644 index 000000000..50e0b6d57 --- /dev/null +++ b/vendor/github.com/ulikunitz/xz/lzma/buffer.go @@ -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 +} |