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Diffstat (limited to 'vendor/github.com/ulikunitz/xz/lzma/decoderdict.go')
-rw-r--r--vendor/github.com/ulikunitz/xz/lzma/decoderdict.go135
1 files changed, 135 insertions, 0 deletions
diff --git a/vendor/github.com/ulikunitz/xz/lzma/decoderdict.go b/vendor/github.com/ulikunitz/xz/lzma/decoderdict.go
new file mode 100644
index 000000000..564a12b83
--- /dev/null
+++ b/vendor/github.com/ulikunitz/xz/lzma/decoderdict.go
@@ -0,0 +1,135 @@
+// 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"
+ "fmt"
+)
+
+// decoderDict provides the dictionary for the decoder. The whole
+// dictionary is used as reader buffer.
+type decoderDict struct {
+ buf buffer
+ head int64
+}
+
+// newDecoderDict creates a new decoder dictionary. The whole dictionary
+// will be used as reader buffer.
+func newDecoderDict(dictCap int) (d *decoderDict, err error) {
+ // lower limit supports easy test cases
+ if !(1 <= dictCap && int64(dictCap) <= MaxDictCap) {
+ return nil, errors.New("lzma: dictCap out of range")
+ }
+ d = &decoderDict{buf: *newBuffer(dictCap)}
+ return d, nil
+}
+
+// Reset clears the dictionary. The read buffer is not changed, so the
+// buffered data can still be read.
+func (d *decoderDict) Reset() {
+ d.head = 0
+}
+
+// WriteByte writes a single byte into the dictionary. It is used to
+// write literals into the dictionary.
+func (d *decoderDict) WriteByte(c byte) error {
+ if err := d.buf.WriteByte(c); err != nil {
+ return err
+ }
+ d.head++
+ return nil
+}
+
+// pos returns the position of the dictionary head.
+func (d *decoderDict) pos() int64 { return d.head }
+
+// dictLen returns the actual length of the dictionary.
+func (d *decoderDict) dictLen() int {
+ capacity := d.buf.Cap()
+ if d.head >= int64(capacity) {
+ return capacity
+ }
+ return int(d.head)
+}
+
+// byteAt returns a byte stored in the dictionary. If the distance is
+// non-positive or exceeds the current length of the dictionary the zero
+// byte is returned.
+func (d *decoderDict) byteAt(dist int) byte {
+ if !(0 < dist && dist <= d.dictLen()) {
+ return 0
+ }
+ i := d.buf.front - dist
+ if i < 0 {
+ i += len(d.buf.data)
+ }
+ return d.buf.data[i]
+}
+
+// writeMatch writes the match at the top of the dictionary. The given
+// distance must point in the current dictionary and the length must not
+// exceed the maximum length 273 supported in LZMA.
+//
+// The error value ErrNoSpace indicates that no space is available in
+// the dictionary for writing. You need to read from the dictionary
+// first.
+func (d *decoderDict) writeMatch(dist int64, length int) error {
+ if !(0 < dist && dist <= int64(d.dictLen())) {
+ return errors.New("writeMatch: distance out of range")
+ }
+ if !(0 < length && length <= maxMatchLen) {
+ return errors.New("writeMatch: length out of range")
+ }
+ if length > d.buf.Available() {
+ return ErrNoSpace
+ }
+ d.head += int64(length)
+
+ i := d.buf.front - int(dist)
+ if i < 0 {
+ i += len(d.buf.data)
+ }
+ for length > 0 {
+ var p []byte
+ if i >= d.buf.front {
+ p = d.buf.data[i:]
+ i = 0
+ } else {
+ p = d.buf.data[i:d.buf.front]
+ i = d.buf.front
+ }
+ if len(p) > length {
+ p = p[:length]
+ }
+ if _, err := d.buf.Write(p); err != nil {
+ panic(fmt.Errorf("d.buf.Write returned error %s", err))
+ }
+ length -= len(p)
+ }
+ return nil
+}
+
+// Write writes the given bytes into the dictionary and advances the
+// head.
+func (d *decoderDict) Write(p []byte) (n int, err error) {
+ n, err = d.buf.Write(p)
+ d.head += int64(n)
+ return n, err
+}
+
+// Available returns the number of available bytes for writing into the
+// decoder dictionary.
+func (d *decoderDict) Available() int { return d.buf.Available() }
+
+// Read reads data from the buffer contained in the decoder dictionary.
+func (d *decoderDict) Read(p []byte) (n int, err error) { return d.buf.Read(p) }
+
+// Buffered returns the number of bytes currently buffered in the
+// decoder dictionary.
+func (d *decoderDict) buffered() int { return d.buf.Buffered() }
+
+// Peek gets data from the buffer without advancing the rear index.
+func (d *decoderDict) peek(p []byte) (n int, err error) { return d.buf.Peek(p) }