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47 lines
1.2 KiB
47 lines
1.2 KiB
// Copyright 2018 Klaus Post. 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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// Based on work Copyright (c) 2013, Yann Collet, released under BSD License. |
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package fse |
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// byteReader provides a byte reader that reads |
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// little endian values from a byte stream. |
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// The input stream is manually advanced. |
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// The reader performs no bounds checks. |
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type byteReader struct { |
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b []byte |
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off int |
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} |
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// init will initialize the reader and set the input. |
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func (b *byteReader) init(in []byte) { |
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b.b = in |
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b.off = 0 |
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} |
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// advance the stream b n bytes. |
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func (b *byteReader) advance(n uint) { |
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b.off += int(n) |
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} |
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// Uint32 returns a little endian uint32 starting at current offset. |
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func (b byteReader) Uint32() uint32 { |
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b2 := b.b[b.off:] |
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b2 = b2[:4] |
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v3 := uint32(b2[3]) |
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v2 := uint32(b2[2]) |
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v1 := uint32(b2[1]) |
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v0 := uint32(b2[0]) |
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return v0 | (v1 << 8) | (v2 << 16) | (v3 << 24) |
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} |
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// unread returns the unread portion of the input. |
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func (b byteReader) unread() []byte { |
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return b.b[b.off:] |
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} |
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// remain will return the number of bytes remaining. |
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func (b byteReader) remain() int { |
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return len(b.b) - b.off |
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}
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