diff options
Diffstat (limited to 'src/pkg/compress/flate/inflate.go')
| -rw-r--r-- | src/pkg/compress/flate/inflate.go | 33 |
1 files changed, 30 insertions, 3 deletions
diff --git a/src/pkg/compress/flate/inflate.go b/src/pkg/compress/flate/inflate.go index 7dc8cf93b..320b80d06 100644 --- a/src/pkg/compress/flate/inflate.go +++ b/src/pkg/compress/flate/inflate.go @@ -2,9 +2,9 @@ // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. -// The flate package implements the DEFLATE compressed data -// format, described in RFC 1951. The gzip and zlib packages -// implement access to DEFLATE-based file formats. +// Package flate implements the DEFLATE compressed data format, described in +// RFC 1951. The gzip and zlib packages implement access to DEFLATE-based file +// formats. package flate import ( @@ -526,6 +526,20 @@ func (f *decompressor) dataBlock() os.Error { return nil } +func (f *decompressor) setDict(dict []byte) { + if len(dict) > len(f.hist) { + // Will only remember the tail. + dict = dict[len(dict)-len(f.hist):] + } + + f.hp = copy(f.hist[:], dict) + if f.hp == len(f.hist) { + f.hp = 0 + f.hfull = true + } + f.hw = f.hp +} + func (f *decompressor) moreBits() os.Error { c, err := f.r.ReadByte() if err != nil { @@ -618,3 +632,16 @@ func NewReader(r io.Reader) io.ReadCloser { go func() { pw.CloseWithError(f.decompress(r, pw)) }() return pr } + +// NewReaderDict is like NewReader but initializes the reader +// with a preset dictionary. The returned Reader behaves as if +// the uncompressed data stream started with the given dictionary, +// which has already been read. NewReaderDict is typically used +// to read data compressed by NewWriterDict. +func NewReaderDict(r io.Reader, dict []byte) io.ReadCloser { + var f decompressor + f.setDict(dict) + pr, pw := io.Pipe() + go func() { pw.CloseWithError(f.decompress(r, pw)) }() + return pr +} |