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7508f98c71
Making xtob take two byte arguments avoids a lot of slicing. This makes
the Parse function faster. In addition, because so much slicing is
avoiding, duplicating the parse logic to ParseBytes resulted in the
function being faster than Parse (<1ns).
The BenchmarkParseBytesNative function has been removed (parseBytes was
identical to ParseBytes). And a new benchmark,
BenchmarkParseBytesUnsafe, has been added to benchmark the old way of
parsing []byte (which is slightly slower than Parse and thus the new
ParseBytes implementation).
benchmark old ns/op new ns/op delta
BenchmarkUUID_MarshalJSON-4 685 667 -2.63%
BenchmarkUUID_UnmarshalJSON-4 1145 1162 +1.48%
BenchmarkParse-4 61.6 56.5 -8.28%
BenchmarkParseBytes-4 65.7 55.9 -14.92%
BenchmarkParseBytesCopy-4 121 115 -4.96%
BenchmarkNew-4 1665 1643 -1.32%
BenchmarkUUID_String-4 112 113 +0.89%
BenchmarkUUID_URN-4 117 119 +1.71%
benchmark old allocs new allocs delta
BenchmarkUUID_MarshalJSON-4 4 4 +0.00%
BenchmarkUUID_UnmarshalJSON-4 2 2 +0.00%
BenchmarkParse-4 0 0 +0.00%
BenchmarkParseBytes-4 0 0 +0.00%
BenchmarkParseBytesCopy-4 1 1 +0.00%
BenchmarkNew-4 1 1 +0.00%
BenchmarkUUID_String-4 1 1 +0.00%
BenchmarkUUID_URN-4 1 1 +0.00%
benchmark old bytes new bytes delta
BenchmarkUUID_MarshalJSON-4 248 248 +0.00%
BenchmarkUUID_UnmarshalJSON-4 248 248 +0.00%
BenchmarkParse-4 0 0 +0.00%
BenchmarkParseBytes-4 0 0 +0.00%
BenchmarkParseBytesCopy-4 48 48 +0.00%
BenchmarkNew-4 16 16 +0.00%
BenchmarkUUID_String-4 48 48 +0.00%
BenchmarkUUID_URN-4 48 48 +0.00%
44 lines
1.9 KiB
Go
44 lines
1.9 KiB
Go
// Copyright 2016 Google Inc. 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 uuid
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import (
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"io"
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)
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// randomBits completely fills slice b with random data.
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func randomBits(b []byte) {
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if _, err := io.ReadFull(rander, b); err != nil {
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panic(err.Error()) // rand should never fail
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}
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}
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// xvalues returns the value of a byte as a hexadecimal digit or 255.
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var xvalues = [256]byte{
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 255, 255, 255, 255, 255, 255,
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255, 10, 11, 12, 13, 14, 15, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 10, 11, 12, 13, 14, 15, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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}
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// xtob converts hex characters x1 and x2 into a byte.
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func xtob(x1, x2 byte) (byte, bool) {
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b1 := xvalues[x1]
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b2 := xvalues[x2]
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return (b1 << 4) | b2, b1 != 255 && b2 != 255
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}
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