diff options
Diffstat (limited to 'vendor/github.com/ulikunitz/xz/lzma/reader.go')
-rw-r--r-- | vendor/github.com/ulikunitz/xz/lzma/reader.go | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/vendor/github.com/ulikunitz/xz/lzma/reader.go b/vendor/github.com/ulikunitz/xz/lzma/reader.go new file mode 100644 index 000000000..2ef3dcaaa --- /dev/null +++ b/vendor/github.com/ulikunitz/xz/lzma/reader.go @@ -0,0 +1,100 @@ +// 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 supports the decoding and encoding of LZMA streams. +// Reader and Writer support the classic LZMA format. Reader2 and +// Writer2 support the decoding and encoding of LZMA2 streams. +// +// The package is written completely in Go and doesn't rely on any external +// library. +package lzma + +import ( + "errors" + "io" +) + +// ReaderConfig stores the parameters for the reader of the classic LZMA +// format. +type ReaderConfig struct { + DictCap int +} + +// fill converts the zero values of the configuration to the default values. +func (c *ReaderConfig) fill() { + if c.DictCap == 0 { + c.DictCap = 8 * 1024 * 1024 + } +} + +// Verify checks the reader configuration for errors. Zero values will +// be replaced by default values. +func (c *ReaderConfig) Verify() error { + c.fill() + if !(MinDictCap <= c.DictCap && int64(c.DictCap) <= MaxDictCap) { + return errors.New("lzma: dictionary capacity is out of range") + } + return nil +} + +// Reader provides a reader for LZMA files or streams. +type Reader struct { + lzma io.Reader + h header + d *decoder +} + +// NewReader creates a new reader for an LZMA stream using the classic +// format. NewReader reads and checks the header of the LZMA stream. +func NewReader(lzma io.Reader) (r *Reader, err error) { + return ReaderConfig{}.NewReader(lzma) +} + +// NewReader creates a new reader for an LZMA stream in the classic +// format. The function reads and verifies the the header of the LZMA +// stream. +func (c ReaderConfig) NewReader(lzma io.Reader) (r *Reader, err error) { + if err = c.Verify(); err != nil { + return nil, err + } + data := make([]byte, HeaderLen) + if _, err := io.ReadFull(lzma, data); err != nil { + if err == io.EOF { + return nil, errors.New("lzma: unexpected EOF") + } + return nil, err + } + r = &Reader{lzma: lzma} + if err = r.h.unmarshalBinary(data); err != nil { + return nil, err + } + if r.h.dictCap < MinDictCap { + return nil, errors.New("lzma: dictionary capacity too small") + } + dictCap := r.h.dictCap + if c.DictCap > dictCap { + dictCap = c.DictCap + } + + state := newState(r.h.properties) + dict, err := newDecoderDict(dictCap) + if err != nil { + return nil, err + } + r.d, err = newDecoder(ByteReader(lzma), state, dict, r.h.size) + if err != nil { + return nil, err + } + return r, nil +} + +// EOSMarker indicates that an EOS marker has been encountered. +func (r *Reader) EOSMarker() bool { + return r.d.eosMarker +} + +// Read returns uncompressed data. +func (r *Reader) Read(p []byte) (n int, err error) { + return r.d.Read(p) +} |