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Move SkChecksum::Murmur3 out of the header.

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As we use this more and more, we end up with more and more inline copies.
On my desktop, this makes Skia ~16K smaller.

Boy perf trybots would be neat.

BUG=skia:

Review URL: https://codereview.chromium.org/1415133003
This commit is contained in:
mtklein 2015-10-21 11:53:27 -07:00 committed by Commit bot
parent b4a20767ee
commit e71000f0df
3 changed files with 49 additions and 38 deletions
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1
gyp/core.gypi
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@ -65,6 +65,7 @@
'<(skia_src_path)/core/SkCachedData.cpp',
'<(skia_src_path)/core/SkCanvas.cpp',
'<(skia_src_path)/core/SkCanvasPriv.h',
'<(skia_src_path)/core/SkChecksum.cpp',
'<(skia_src_path)/core/SkChunkAlloc.cpp',
'<(skia_src_path)/core/SkClipStack.cpp',
'<(skia_src_path)/core/SkColor.cpp',

39
include/private/SkChecksum.h
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@ -76,44 +76,7 @@ public:
* @param seed Initial hash seed. (optional)
* @return hash result
*/
static uint32_t Murmur3(const void* data, size_t bytes, uint32_t seed=0) {
// Use may_alias to remind the compiler we're intentionally violating strict aliasing,
// and so not to apply strict-aliasing-based optimizations.
typedef uint32_t SK_ATTRIBUTE(may_alias) aliased_uint32_t;
typedef uint8_t SK_ATTRIBUTE(may_alias) aliased_uint8_t;
// Handle 4 bytes at a time while possible.
const aliased_uint32_t* safe_data = (const aliased_uint32_t*)data;
const size_t words = bytes/4;
uint32_t hash = seed;
for (size_t i = 0; i < words; i++) {
uint32_t k = safe_data[i];
k *= 0xcc9e2d51;
k = (k << 15) | (k >> 17);
k *= 0x1b873593;
hash ^= k;
hash = (hash << 13) | (hash >> 19);
hash *= 5;
hash += 0xe6546b64;
}
// Handle last 0-3 bytes.
const aliased_uint8_t* safe_tail = (const uint8_t*)(safe_data + words);
uint32_t k = 0;
switch (bytes & 3) {
case 3: k ^= safe_tail[2] << 16;
case 2: k ^= safe_tail[1] << 8;
case 1: k ^= safe_tail[0] << 0;
k *= 0xcc9e2d51;
k = (k << 15) | (k >> 17);
k *= 0x1b873593;
hash ^= k;
}
hash ^= bytes;
return Mix(hash);
}
static uint32_t Murmur3(const void* data, size_t bytes, uint32_t seed=0);
/**
* Compute a 32-bit checksum for a given data block

47
src/core/SkChecksum.cpp Normal file
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@ -0,0 +1,47 @@
/*
* Copyright 2015 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkChecksum.h"
uint32_t SkChecksum::Murmur3(const void* data, size_t bytes, uint32_t seed) {
// Use may_alias to remind the compiler we're intentionally violating strict aliasing,
// and so not to apply strict-aliasing-based optimizations.
typedef uint32_t SK_ATTRIBUTE(may_alias) aliased_uint32_t;
typedef uint8_t SK_ATTRIBUTE(may_alias) aliased_uint8_t;
// Handle 4 bytes at a time while possible.
const aliased_uint32_t* safe_data = (const aliased_uint32_t*)data;
const size_t words = bytes/4;
uint32_t hash = seed;
for (size_t i = 0; i < words; i++) {
uint32_t k = safe_data[i];
k *= 0xcc9e2d51;
k = (k << 15) | (k >> 17);
k *= 0x1b873593;
hash ^= k;
hash = (hash << 13) | (hash >> 19);
hash *= 5;
hash += 0xe6546b64;
}
// Handle last 0-3 bytes.
const aliased_uint8_t* safe_tail = (const uint8_t*)(safe_data + words);
uint32_t k = 0;
switch (bytes & 3) {
case 3: k ^= safe_tail[2] << 16;
case 2: k ^= safe_tail[1] << 8;
case 1: k ^= safe_tail[0] << 0;
k *= 0xcc9e2d51;
k = (k << 15) | (k >> 17);
k *= 0x1b873593;
hash ^= k;
}
hash ^= bytes;
return SkChecksum::Mix(hash);
}