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.
81 lines
1.8 KiB
Go
81 lines
1.8 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
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import (
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"errors"
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"fmt"
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"unicode"
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)
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// operation represents an operation on the dictionary during encoding or
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// decoding.
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type operation interface {
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Len() int
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}
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// rep represents a repetition at the given distance and the given length
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type match struct {
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// supports all possible distance values, including the eos marker
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distance int64
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// length
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n int
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}
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// verify checks whether the match is valid. If that is not the case an
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// error is returned.
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func (m match) verify() error {
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if !(minDistance <= m.distance && m.distance <= maxDistance) {
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return errors.New("distance out of range")
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}
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if !(1 <= m.n && m.n <= maxMatchLen) {
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return errors.New("length out of range")
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}
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return nil
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}
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// l return the l-value for the match, which is the difference of length
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// n and 2.
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func (m match) l() uint32 {
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return uint32(m.n - minMatchLen)
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}
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// dist returns the dist value for the match, which is one less of the
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// distance stored in the match.
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func (m match) dist() uint32 {
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return uint32(m.distance - minDistance)
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}
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// Len returns the number of bytes matched.
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func (m match) Len() int {
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return m.n
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}
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// String returns a string representation for the repetition.
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func (m match) String() string {
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return fmt.Sprintf("M{%d,%d}", m.distance, m.n)
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}
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// lit represents a single byte literal.
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type lit struct {
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b byte
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}
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// Len returns 1 for the single byte literal.
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func (l lit) Len() int {
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return 1
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}
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// String returns a string representation for the literal.
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func (l lit) String() string {
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var c byte
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if unicode.IsPrint(rune(l.b)) {
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c = l.b
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} else {
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c = '.'
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}
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return fmt.Sprintf("L{%c/%02x}", c, l.b)
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}
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