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.
50 lines
1.4 KiB
Go
50 lines
1.4 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 "fmt"
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// directCodec allows the encoding and decoding of values with a fixed number
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// of bits. The number of bits must be in the range [1,32].
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type directCodec byte
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// makeDirectCodec creates a directCodec. The function panics if the number of
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// bits is not in the range [1,32].
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func makeDirectCodec(bits int) directCodec {
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if !(1 <= bits && bits <= 32) {
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panic(fmt.Errorf("bits=%d out of range", bits))
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}
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return directCodec(bits)
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}
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// Bits returns the number of bits supported by this codec.
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func (dc directCodec) Bits() int {
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return int(dc)
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}
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// Encode uses the range encoder to encode a value with the fixed number of
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// bits. The most-significant bit is encoded first.
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func (dc directCodec) Encode(e *rangeEncoder, v uint32) error {
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for i := int(dc) - 1; i >= 0; i-- {
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if err := e.DirectEncodeBit(v >> uint(i)); err != nil {
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return err
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}
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}
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return nil
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}
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// Decode uses the range decoder to decode a value with the given number of
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// given bits. The most-significant bit is decoded first.
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func (dc directCodec) Decode(d *rangeDecoder) (v uint32, err error) {
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for i := int(dc) - 1; i >= 0; i-- {
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x, err := d.DirectDecodeBit()
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if err != nil {
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return 0, err
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}
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v = (v << 1) | x
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}
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return v, nil
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}
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