989489096e
This commit implements a massive refactor of the repository, and moves the build system over to use Mage (magefile.org) which should allow seamless building across multiple platforms.
101 lines
2.6 KiB
Go
101 lines
2.6 KiB
Go
// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package lzma supports the decoding and encoding of LZMA streams.
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// Reader and Writer support the classic LZMA format. Reader2 and
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// Writer2 support the decoding and encoding of LZMA2 streams.
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//
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// The package is written completely in Go and doesn't rely on any external
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// library.
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package lzma
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import (
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"errors"
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"io"
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)
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// ReaderConfig stores the parameters for the reader of the classic LZMA
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// format.
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type ReaderConfig struct {
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DictCap int
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}
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// fill converts the zero values of the configuration to the default values.
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func (c *ReaderConfig) fill() {
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if c.DictCap == 0 {
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c.DictCap = 8 * 1024 * 1024
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}
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}
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// Verify checks the reader configuration for errors. Zero values will
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// be replaced by default values.
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func (c *ReaderConfig) Verify() error {
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c.fill()
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if !(MinDictCap <= c.DictCap && int64(c.DictCap) <= MaxDictCap) {
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return errors.New("lzma: dictionary capacity is out of range")
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}
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return nil
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}
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// Reader provides a reader for LZMA files or streams.
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type Reader struct {
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lzma io.Reader
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h header
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d *decoder
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}
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// NewReader creates a new reader for an LZMA stream using the classic
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// format. NewReader reads and checks the header of the LZMA stream.
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func NewReader(lzma io.Reader) (r *Reader, err error) {
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return ReaderConfig{}.NewReader(lzma)
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}
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// NewReader creates a new reader for an LZMA stream in the classic
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// format. The function reads and verifies the the header of the LZMA
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// stream.
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func (c ReaderConfig) NewReader(lzma io.Reader) (r *Reader, err error) {
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if err = c.Verify(); err != nil {
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return nil, err
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}
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data := make([]byte, HeaderLen)
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if _, err := io.ReadFull(lzma, data); err != nil {
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if err == io.EOF {
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return nil, errors.New("lzma: unexpected EOF")
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}
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return nil, err
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}
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r = &Reader{lzma: lzma}
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if err = r.h.unmarshalBinary(data); err != nil {
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return nil, err
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}
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if r.h.dictCap < MinDictCap {
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return nil, errors.New("lzma: dictionary capacity too small")
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}
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dictCap := r.h.dictCap
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if c.DictCap > dictCap {
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dictCap = c.DictCap
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}
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state := newState(r.h.properties)
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dict, err := newDecoderDict(dictCap)
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if err != nil {
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return nil, err
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}
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r.d, err = newDecoder(ByteReader(lzma), state, dict, r.h.size)
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if err != nil {
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return nil, err
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}
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return r, nil
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}
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// EOSMarker indicates that an EOS marker has been encountered.
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func (r *Reader) EOSMarker() bool {
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return r.d.eosMarker
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}
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// Read returns uncompressed data.
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func (r *Reader) Read(p []byte) (n int, err error) {
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return r.d.Read(p)
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}
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