mirror of
https://github.com/go-gitea/gitea.git
synced 2024-08-28 23:27:27 +02:00
101 lines
2.6 KiB
Go
Vendored
101 lines
2.6 KiB
Go
Vendored
// Copyright 2014-2021 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)
|
|
}
|