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38 lines
1.1 KiB
38 lines
1.1 KiB
// Copyright 2014 The zappy Authors. 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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// Copyright 2011 The Snappy-Go Authors. 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 SNAPPY-GO-LICENSE file.
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package zappy // import "modernc.org/zappy"
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import (
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"encoding/binary"
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)
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// We limit how far copy back-references can go, the same as the snappy C++
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// code.
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const maxOffset = 1 << 20
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// emitCopy writes a copy chunk and returns the number of bytes written.
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func emitCopy(dst []byte, offset, length int) (n int) {
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n = binary.PutVarint(dst, int64(-length))
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n += binary.PutUvarint(dst[n:], uint64(offset))
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return
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}
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// emitLiteral writes a literal chunk and returns the number of bytes written.
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func emitLiteral(dst, lit []byte) (n int) {
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n = binary.PutVarint(dst, int64(len(lit)-1))
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n += copy(dst[n:], lit)
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return
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}
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// MaxEncodedLen returns the maximum length of a zappy block, given its
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// uncompressed length.
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func MaxEncodedLen(srcLen int) int {
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return 10 + srcLen + (srcLen+1)/2
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}
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