| Index: include/core/SkChecksum.h
|
| diff --git a/include/core/SkChecksum.h b/include/core/SkChecksum.h
|
| deleted file mode 100644
|
| index bf3228f91db8722337e9b06db0fb23fb491d4e37..0000000000000000000000000000000000000000
|
| --- a/include/core/SkChecksum.h
|
| +++ /dev/null
|
| @@ -1,135 +0,0 @@
|
| -/*
|
| - * Copyright 2012 Google Inc.
|
| - *
|
| - * Use of this source code is governed by a BSD-style license that can be
|
| - * found in the LICENSE file.
|
| - */
|
| -
|
| -#ifndef SkChecksum_DEFINED
|
| -#define SkChecksum_DEFINED
|
| -
|
| -#include "SkTypes.h"
|
| -
|
| -/**
|
| - * Computes a 32bit checksum from a blob of 32bit aligned data. This is meant
|
| - * to be very very fast, as it is used internally by the font cache, in
|
| - * conjuction with the entire raw key. This algorithm does not generate
|
| - * unique values as well as others (e.g. MD5) but it performs much faster.
|
| - * Skia's use cases can survive non-unique values (since the entire key is
|
| - * always available). Clients should only be used in circumstances where speed
|
| - * over uniqueness is at a premium.
|
| - */
|
| -class SkChecksum : SkNoncopyable {
|
| -private:
|
| - /*
|
| - * Our Rotate and Mash helpers are meant to automatically do the right
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| - * thing depending if sizeof(uintptr_t) is 4 or 8.
|
| - */
|
| - enum {
|
| - ROTR = 17,
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| - ROTL = sizeof(uintptr_t) * 8 - ROTR,
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| - HALFBITS = sizeof(uintptr_t) * 4
|
| - };
|
| -
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| - static inline uintptr_t Mash(uintptr_t total, uintptr_t value) {
|
| - return ((total >> ROTR) | (total << ROTL)) ^ value;
|
| - }
|
| -
|
| -public:
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| -
|
| - /**
|
| - * Calculate 32-bit Murmur hash (murmur3).
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| - * This should take 2-3x longer than SkChecksum::Compute, but is a considerably better hash.
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| - * See en.wikipedia.org/wiki/MurmurHash.
|
| - *
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| - * @param data Memory address of the data block to be processed. Must be 32-bit aligned.
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| - * @param size Size of the data block in bytes. Must be a multiple of 4.
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| - * @param seed Initial hash seed. (optional)
|
| - * @return hash result
|
| - */
|
| - static uint32_t Murmur3(const uint32_t* data, size_t bytes, uint32_t seed=0) {
|
| - SkASSERT(SkIsAlign4(bytes));
|
| - const size_t words = bytes/4;
|
| -
|
| - uint32_t hash = seed;
|
| - for (size_t i = 0; i < words; i++) {
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| - uint32_t k = data[i];
|
| - k *= 0xcc9e2d51;
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| - k = (k << 15) | (k >> 17);
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| - k *= 0x1b873593;
|
| -
|
| - hash ^= k;
|
| - hash = (hash << 13) | (hash >> 19);
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| - hash *= 5;
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| - hash += 0xe6546b64;
|
| - }
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| - hash ^= bytes;
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| - hash ^= hash >> 16;
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| - hash *= 0x85ebca6b;
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| - hash ^= hash >> 13;
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| - hash *= 0xc2b2ae35;
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| - hash ^= hash >> 16;
|
| - return hash;
|
| - }
|
| -
|
| - /**
|
| - * Compute a 32-bit checksum for a given data block
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| - *
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| - * WARNING: this algorithm is tuned for efficiency, not backward/forward
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| - * compatibility. It may change at any time, so a checksum generated with
|
| - * one version of the Skia code may not match a checksum generated with
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| - * a different version of the Skia code.
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| - *
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| - * @param data Memory address of the data block to be processed. Must be
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| - * 32-bit aligned.
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| - * @param size Size of the data block in bytes. Must be a multiple of 4.
|
| - * @return checksum result
|
| - */
|
| - static uint32_t Compute(const uint32_t* data, size_t size) {
|
| - SkASSERT(SkIsAlign4(size));
|
| -
|
| - /*
|
| - * We want to let the compiler use 32bit or 64bit addressing and math
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| - * so we use uintptr_t as our magic type. This makes the code a little
|
| - * more obscure (we can't hard-code 32 or 64 anywhere, but have to use
|
| - * sizeof()).
|
| - */
|
| - uintptr_t result = 0;
|
| - const uintptr_t* ptr = reinterpret_cast<const uintptr_t*>(data);
|
| -
|
| - /*
|
| - * count the number of quad element chunks. This takes into account
|
| - * if we're on a 32bit or 64bit arch, since we use sizeof(uintptr_t)
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| - * to compute how much to shift-down the size.
|
| - */
|
| - size_t n4 = size / (sizeof(uintptr_t) << 2);
|
| - for (size_t i = 0; i < n4; ++i) {
|
| - result = Mash(result, *ptr++);
|
| - result = Mash(result, *ptr++);
|
| - result = Mash(result, *ptr++);
|
| - result = Mash(result, *ptr++);
|
| - }
|
| - size &= ((sizeof(uintptr_t) << 2) - 1);
|
| -
|
| - data = reinterpret_cast<const uint32_t*>(ptr);
|
| - const uint32_t* stop = data + (size >> 2);
|
| - while (data < stop) {
|
| - result = Mash(result, *data++);
|
| - }
|
| -
|
| - /*
|
| - * smash us down to 32bits if we were 64. Note that when uintptr_t is
|
| - * 32bits, this code-path should go away, but I still got a warning
|
| - * when I wrote
|
| - * result ^= result >> 32;
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| - * since >>32 is undefined for 32bit ints, hence the wacky HALFBITS
|
| - * define.
|
| - */
|
| - if (8 == sizeof(result)) {
|
| - result ^= result >> HALFBITS;
|
| - }
|
| - return static_cast<uint32_t>(result);
|
| - }
|
| -};
|
| -
|
| -#endif
|
|
|