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-rw-r--r--DEPS1
-rw-r--r--gyp/utils.gyp23
-rw-r--r--src/utils/SkCityHash.cpp23
-rw-r--r--src/utils/SkCityHash.h47
-rw-r--r--src/utils/SkConsistentChecksum.h95
-rw-r--r--src/utils/cityhash/README2
-rw-r--r--src/utils/cityhash/config.h17
-rw-r--r--tests/ChecksumTest.cpp102
8 files changed, 166 insertions, 144 deletions
diff --git a/DEPS b/DEPS
index 55a6401538..5cd2370931 100644
--- a/DEPS
+++ b/DEPS
@@ -9,6 +9,7 @@ use_relative_paths = True
#
deps = {
"third_party/externals/angle" : "http://angleproject.googlecode.com/svn/trunk@1268",
+ "third_party/externals/cityhash" : "http://cityhash.googlecode.com/svn/trunk@11",
"third_party/externals/freetype" : "https://android.googlesource.com/platform/external/freetype.git",
"third_party/externals/gyp" : "http://gyp.googlecode.com/svn/trunk@1517",
"third_party/externals/libjpeg" : "http://src.chromium.org/svn/trunk/src/third_party/libjpeg@125399",
diff --git a/gyp/utils.gyp b/gyp/utils.gyp
index 5658f045bf..b2833f2a0f 100644
--- a/gyp/utils.gyp
+++ b/gyp/utils.gyp
@@ -5,6 +5,9 @@
'product_name': 'skia_utils',
'type': 'static_library',
'standalone_static_library': 1,
+ 'dependencies': [
+ 'cityhash',
+ ],
'include_dirs': [
'../include/config',
'../include/core',
@@ -23,6 +26,7 @@
'../include/utils/SkCountdown.h',
'../include/utils/SkRunnable.h',
'../include/utils/SkThreadPool.h',
+ '../src/utils/SkCityHash.cpp',
'../src/utils/SkCondVar.cpp',
'../src/utils/SkCountdown.cpp',
'../src/utils/SkThreadPool.cpp',
@@ -193,6 +197,25 @@
],
},
},
+ {
+ 'target_name': 'cityhash',
+ 'type': 'static_library',
+ 'standalone_static_library': 1,
+ 'include_dirs': [
+ '../include/config',
+ '../include/core',
+ '../src/utils/cityhash',
+ '../third_party/externals/cityhash/src',
+ ],
+ 'sources': [
+ '../third_party/externals/cityhash/src/city.cc',
+ ],
+ 'direct_dependent_settings': {
+ 'include_dirs': [
+ '../third_party/externals/cityhash/src',
+ ],
+ },
+ },
],
}
diff --git a/src/utils/SkCityHash.cpp b/src/utils/SkCityHash.cpp
new file mode 100644
index 0000000000..a21aa89634
--- /dev/null
+++ b/src/utils/SkCityHash.cpp
@@ -0,0 +1,23 @@
+/*
+ * Copyright 2012 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+/**
+ * Pass any calls through to the CityHash library.
+ * This is the only source file that accesses the CityHash code directly.
+ */
+
+#include "SkCityHash.h"
+#include "SkTypes.h"
+#include "city.h"
+
+uint32_t SkCityHash::Compute32(const char *data, size_t size) {
+ return CityHash32(data, size);
+}
+
+uint64_t SkCityHash::Compute64(const char *data, size_t size) {
+ return CityHash64(data, size);
+}
diff --git a/src/utils/SkCityHash.h b/src/utils/SkCityHash.h
new file mode 100644
index 0000000000..c69e0fb37b
--- /dev/null
+++ b/src/utils/SkCityHash.h
@@ -0,0 +1,47 @@
+/*
+ * Copyright 2012 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+/**
+ * Hash functions, using the CityHash algorithm.
+ *
+ * Results are guaranteed to be:
+ * 1. consistent across revisions of the library (for a given set
+ * of bytes, the checksum generated at one revision of the Skia
+ * library will match the one generated on any other revision of
+ * the Skia library)
+ * 2. consistent across platforms (for a given
+ * set of bytes, the checksum generated on one platform will
+ * match the one generated on any other platform)
+ */
+
+#ifndef SkCityHash_DEFINED
+#define SkCityHash_DEFINED
+
+#include "SkTypes.h"
+
+class SkCityHash : SkNoncopyable {
+public:
+ /**
+ * Compute a 32-bit checksum for a given data block.
+ *
+ * @param data Memory address of the data block to be processed.
+ * @param size Size of the data block in bytes.
+ * @return checksum result
+ */
+ static uint32_t Compute32(const char *data, size_t size);
+
+ /**
+ * Compute a 64-bit checksum for a given data block.
+ *
+ * @param data Memory address of the data block to be processed.
+ * @param size Size of the data block in bytes.
+ * @return checksum result
+ */
+ static uint64_t Compute64(const char *data, size_t size);
+};
+
+#endif
diff --git a/src/utils/SkConsistentChecksum.h b/src/utils/SkConsistentChecksum.h
deleted file mode 100644
index 8b7c53dde8..0000000000
--- a/src/utils/SkConsistentChecksum.h
+++ /dev/null
@@ -1,95 +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 SkConsistentChecksum_DEFINED
-#define SkConsistentChecksum_DEFINED
-
-#include "SkTypes.h"
-
-class SkConsistentChecksum : SkNoncopyable {
-private:
- /*
- * Our Rotate and Mash helpers are meant to automatically do the right
- * thing depending if sizeof(uintptr_t) is 4 or 8.
- */
- enum {
- ROTR = 17,
- ROTL = sizeof(uintptr_t) * 8 - ROTR,
- HALFBITS = sizeof(uintptr_t) * 4
- };
-
- static inline uintptr_t Mash(uintptr_t total, uintptr_t value) {
- return ((total >> ROTR) | (total << ROTL)) ^ value;
- }
-
-public:
- /**
- * Compute a 32-bit checksum for a given data block
- *
- * WARNING: As of 1 Nov 2012, this algorithm is still in
- * flux... but once we get it doing what we want, it will be:
- * 1. consistent across revisions of the library (for a given set
- * of bytes, the checksum generated at one revision of the Skia
- * library will match the one generated on any other revision of
- * the Skia library)
- * 2. consistent across platforms (for a given
- * set of bytes, the checksum generated on one platform will
- * match the one generated on any other platform)
- *
- * @param data Memory address of the data block to be processed. Must be
- * 32-bit aligned.
- * @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
- * 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)
- * 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;
- * 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
diff --git a/src/utils/cityhash/README b/src/utils/cityhash/README
new file mode 100644
index 0000000000..d93928857f
--- /dev/null
+++ b/src/utils/cityhash/README
@@ -0,0 +1,2 @@
+This directory contains files needed to build third_party/externals/cityhash
+(such as the config.h file that would normally be created by autoconf)
diff --git a/src/utils/cityhash/config.h b/src/utils/cityhash/config.h
new file mode 100644
index 0000000000..bd3641658e
--- /dev/null
+++ b/src/utils/cityhash/config.h
@@ -0,0 +1,17 @@
+/*
+ * Copyright 2012 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+/**
+ * Converts from Skia build flags to the macro definitions cityhash normally
+ * gets from autoconf.
+ */
+
+#include "SkTypes.h"
+
+#ifdef SK_CPU_BENDIAN
+ #define WORDS_BIGENDIAN 1
+#endif
diff --git a/tests/ChecksumTest.cpp b/tests/ChecksumTest.cpp
index 5d5d83bc93..dea0eef856 100644
--- a/tests/ChecksumTest.cpp
+++ b/tests/ChecksumTest.cpp
@@ -7,7 +7,10 @@
*/
#include "Test.h"
#include "SkChecksum.h"
-#include "SkConsistentChecksum.h"
+#include "SkCityHash.h"
+
+// Word size that is large enough to hold results of any checksum type.
+typedef uint64_t checksum_result;
namespace skiatest {
class ChecksumTestClass : public Test {
@@ -22,26 +25,25 @@ namespace skiatest {
private:
enum Algorithm {
kSkChecksum,
- kSkConsistentChecksum
+ kSkCityHash32,
+ kSkCityHash64
};
// Call Compute(data, size) on the appropriate checksum algorithm,
// depending on this->fWhichAlgorithm.
- uint32_t ComputeChecksum(uint32_t* data, size_t size) {
- // Our checksum algorithms require 32-bit aligned data.
- // If either of these tests fail, then the algorithm
- // doesn't have a chance.
- REPORTER_ASSERT_MESSAGE(fReporter,
- reinterpret_cast<uintptr_t>(data) % 4 == 0,
- "test data pointer is not 32-bit aligned");
- REPORTER_ASSERT_MESSAGE(fReporter, SkIsAlign4(size),
- "test data size is not 32-bit aligned");
-
+ checksum_result ComputeChecksum(const char *data, size_t size) {
switch(fWhichAlgorithm) {
case kSkChecksum:
- return SkChecksum::Compute(data, size);
- case kSkConsistentChecksum:
- return SkConsistentChecksum::Compute(data, size);
+ REPORTER_ASSERT_MESSAGE(fReporter,
+ reinterpret_cast<uintptr_t>(data) % 4 == 0,
+ "test data pointer is not 32-bit aligned");
+ REPORTER_ASSERT_MESSAGE(fReporter, SkIsAlign4(size),
+ "test data size is not 32-bit aligned");
+ return SkChecksum::Compute(reinterpret_cast<const uint32_t *>(data), size);
+ case kSkCityHash32:
+ return SkCityHash::Compute32(data, size);
+ case kSkCityHash64:
+ return SkCityHash::Compute64(data, size);
default:
SkString message("fWhichAlgorithm has unknown value ");
message.appendf("%d", fWhichAlgorithm);
@@ -55,16 +57,22 @@ namespace skiatest {
// generates the same results if called twice over the same data.
void TestChecksumSelfConsistency(size_t buf_size) {
SkAutoMalloc storage(buf_size);
- uint32_t* ptr = (uint32_t*)storage.get();
- char* cptr = (char*)ptr;
+ char* ptr = reinterpret_cast<char *>(storage.get());
+
+ REPORTER_ASSERT(fReporter,
+ GetTestDataChecksum(8, 0) ==
+ GetTestDataChecksum(8, 0));
+ REPORTER_ASSERT(fReporter,
+ GetTestDataChecksum(8, 0) !=
+ GetTestDataChecksum(8, 1));
sk_bzero(ptr, buf_size);
- uint32_t prev = 0;
+ checksum_result prev = 0;
// assert that as we change values (from 0 to non-zero) in
// our buffer, we get a different value
for (size_t i = 0; i < buf_size; ++i) {
- cptr[i] = (i & 0x7f) + 1; // need some non-zero value here
+ ptr[i] = (i & 0x7f) + 1; // need some non-zero value here
// Try checksums of different-sized chunks, but always
// 32-bit aligned and big enough to contain all the
@@ -73,9 +81,9 @@ namespace skiatest {
size_t checksum_size = (((i/4)+1)*4);
REPORTER_ASSERT(fReporter, checksum_size <= buf_size);
- uint32_t curr = ComputeChecksum(ptr, checksum_size);
+ checksum_result curr = ComputeChecksum(ptr, checksum_size);
REPORTER_ASSERT(fReporter, prev != curr);
- uint32_t again = ComputeChecksum(ptr, checksum_size);
+ checksum_result again = ComputeChecksum(ptr, checksum_size);
REPORTER_ASSERT(fReporter, again == curr);
prev = curr;
}
@@ -84,48 +92,49 @@ namespace skiatest {
// Return the checksum of a buffer of bytes 'len' long.
// The pattern of values within the buffer will be consistent
// for every call, based on 'seed'.
- uint32_t GetTestDataChecksum(size_t len, char seed=0) {
+ checksum_result GetTestDataChecksum(size_t len, char seed=0) {
SkAutoMalloc storage(len);
- uint32_t* start = (uint32_t *)storage.get();
- char* ptr = (char *)start;
+ char* start = reinterpret_cast<char *>(storage.get());
+ char* ptr = start;
for (size_t i = 0; i < len; ++i) {
*ptr++ = ((seed+i) & 0x7f);
}
- uint32_t result = ComputeChecksum(start, len);
+ checksum_result result = ComputeChecksum(start, len);
return result;
}
void RunTest() {
// Test self-consistency of checksum algorithms.
fWhichAlgorithm = kSkChecksum;
- REPORTER_ASSERT(fReporter,
- GetTestDataChecksum(8, 0) ==
- GetTestDataChecksum(8, 0));
- REPORTER_ASSERT(fReporter,
- GetTestDataChecksum(8, 0) !=
- GetTestDataChecksum(8, 1));
TestChecksumSelfConsistency(128);
- fWhichAlgorithm = kSkConsistentChecksum;
- REPORTER_ASSERT(fReporter,
- GetTestDataChecksum(8, 0) ==
- GetTestDataChecksum(8, 0));
- REPORTER_ASSERT(fReporter,
- GetTestDataChecksum(8, 0) !=
- GetTestDataChecksum(8, 1));
+ fWhichAlgorithm = kSkCityHash32;
+ TestChecksumSelfConsistency(128);
+ fWhichAlgorithm = kSkCityHash64;
TestChecksumSelfConsistency(128);
// Test checksum results that should be consistent across
// versions and platforms.
fWhichAlgorithm = kSkChecksum;
REPORTER_ASSERT(fReporter, ComputeChecksum(NULL, 0) == 0);
- fWhichAlgorithm = kSkConsistentChecksum;
- REPORTER_ASSERT(fReporter, ComputeChecksum(NULL, 0) == 0);
- REPORTER_ASSERT(fReporter, GetTestDataChecksum(4) == 0x03020100);
- REPORTER_ASSERT(fReporter, GetTestDataChecksum(8) == 0x07860485);
+ fWhichAlgorithm = kSkCityHash32;
+ REPORTER_ASSERT(fReporter, ComputeChecksum(NULL, 0) == 0xdc56d17a);
+ REPORTER_ASSERT(fReporter, GetTestDataChecksum(4) == 0x616e1132);
+ REPORTER_ASSERT(fReporter, GetTestDataChecksum(8) == 0xeb0fd2d6);
+ REPORTER_ASSERT(fReporter, GetTestDataChecksum(128) == 0x5321e430);
+ REPORTER_ASSERT(fReporter, GetTestDataChecksum(132) == 0x924a10e4);
+ REPORTER_ASSERT(fReporter, GetTestDataChecksum(256) == 0xd4de9dc9);
+ REPORTER_ASSERT(fReporter, GetTestDataChecksum(260) == 0xecf0325d);
+ fWhichAlgorithm = kSkCityHash64;
+ REPORTER_ASSERT(fReporter, ComputeChecksum(NULL, 0) == 0x9ae16a3b2f90404f);
+ REPORTER_ASSERT(fReporter, GetTestDataChecksum(4) == 0x82bffd898958e540);
+ REPORTER_ASSERT(fReporter, GetTestDataChecksum(8) == 0xad5a13e1e8e93b98);
+ REPORTER_ASSERT(fReporter, GetTestDataChecksum(128) == 0x10b153630af1f395);
+ REPORTER_ASSERT(fReporter, GetTestDataChecksum(132) == 0x7db71dc4adcc6647);
+ REPORTER_ASSERT(fReporter, GetTestDataChecksum(256) == 0xeee763519b91b010);
+ REPORTER_ASSERT(fReporter, GetTestDataChecksum(260) == 0x2fe19e0b2239bc23);
// TODO: note the weakness exposed by these collisions...
- // We need to improve the SkConsistentChecksum algorithm
- // (and maybe SkChecksum too?)
+ // We need to improve the SkChecksum algorithm.
// We would prefer that these asserts FAIL!
// Filed as https://code.google.com/p/skia/issues/detail?id=981
// ('SkChecksum algorithm allows for way too many collisions')
@@ -134,11 +143,6 @@ namespace skiatest {
GetTestDataChecksum(128) == GetTestDataChecksum(256));
REPORTER_ASSERT(fReporter,
GetTestDataChecksum(132) == GetTestDataChecksum(260));
- fWhichAlgorithm = kSkConsistentChecksum;
- REPORTER_ASSERT(fReporter, GetTestDataChecksum(128) == 0);
- REPORTER_ASSERT(fReporter, GetTestDataChecksum(132) == 0x03020100);
- REPORTER_ASSERT(fReporter, GetTestDataChecksum(256) == 0);
- REPORTER_ASSERT(fReporter, GetTestDataChecksum(260) == 0x03020100);
}
Reporter* fReporter;
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-24 07:01:16 +0000