Split off SkConsistentChecksum from SkChecksum
as part of https://goto.google.com/ImprovingTheSkiaRebaseliningProcess
Review URL: https://codereview.appspot.com/6820074
git-svn-id: http://skia.googlecode.com/svn/trunk@6270 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/tests/ChecksumTest.cpp b/tests/ChecksumTest.cpp
new file mode 100644
index 0000000..3425bcd
--- /dev/null
+++ b/tests/ChecksumTest.cpp
@@ -0,0 +1,120 @@
+
+/*
+ * Copyright 2012 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+#include "Test.h"
+#include "SkChecksum.h"
+#include "SkConsistentChecksum.h"
+
+namespace skiatest {
+ class ChecksumTestClass : public Test {
+ public:
+ static Test* Factory(void*) {return SkNEW(ChecksumTestClass); }
+ protected:
+ virtual void onGetName(SkString* name) { name->set("Checksum"); }
+ virtual void onRun(Reporter* reporter) {
+ this->fReporter = reporter;
+ RunTest();
+ }
+ private:
+ enum Algorithm {
+ kSkChecksum,
+ kSkConsistentChecksum
+ };
+
+ // 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");
+
+ switch(fWhichAlgorithm) {
+ case kSkChecksum:
+ return SkChecksum::Compute(data, size);
+ case kSkConsistentChecksum:
+ return SkConsistentChecksum::Compute(data, size);
+ default:
+ SkString message("fWhichAlgorithm has unknown value ");
+ message.appendf("%d", fWhichAlgorithm);
+ fReporter->reportFailed(message);
+ }
+ // we never get here
+ return 0;
+ }
+
+ // Confirm that the checksum algorithm (specified by fWhichAlgorithm)
+ // 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;
+
+ sk_bzero(ptr, buf_size);
+ uint32_t 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
+
+ // Try checksums of different-sized chunks, but always
+ // 32-bit aligned and big enough to contain all the
+ // nonzero bytes.
+ size_t checksum_size = (((i/4)+1)*4);
+ REPORTER_ASSERT(fReporter, checksum_size <= buf_size);
+
+ uint32_t curr = ComputeChecksum(ptr, checksum_size);
+ REPORTER_ASSERT(fReporter, prev != curr);
+ uint32_t again = ComputeChecksum(ptr, checksum_size);
+ REPORTER_ASSERT(fReporter, again == curr);
+ prev = curr;
+ }
+ }
+
+ // Return the checksum of a portion of this static test data
+ // (8 bytes repeated twice): "1234567812345678"
+ uint32_t GetTestDataChecksum(size_t offset, size_t len) {
+ static char testbytes[] = "1234567812345678";
+ uint32_t* ptr = reinterpret_cast<uint32_t*>(testbytes);
+ return ComputeChecksum(ptr, len);
+ }
+
+ void RunTest() {
+ // Test self-consistency of checksum algorithms.
+ fWhichAlgorithm = kSkChecksum;
+ REPORTER_ASSERT(fReporter,
+ GetTestDataChecksum(0, 8) ==
+ GetTestDataChecksum(8, 8));
+ TestChecksumSelfConsistency(128);
+ fWhichAlgorithm = kSkConsistentChecksum;
+ REPORTER_ASSERT(fReporter,
+ GetTestDataChecksum(0, 8) ==
+ GetTestDataChecksum(8, 8));
+ 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(0, 8) == 0xa12fac2c);
+ REPORTER_ASSERT(fReporter, GetTestDataChecksum(8, 8) == 0xa12fac2c);
+ REPORTER_ASSERT(fReporter, GetTestDataChecksum(8, 4) == 0x34333231);
+ }
+
+ Reporter* fReporter;
+ Algorithm fWhichAlgorithm;
+ };
+
+ static TestRegistry gReg(ChecksumTestClass::Factory);
+}