skia2/tests/ClampRangeTest.cpp
commit-bot@chromium.org 86398e5d91 Avoid undefined behavior and enable asserts in ClampTest.
The old code here wasn't being careful to avoid int32_t overflow in slow_check.  Fix that.

R_ASSERT hasn't been doing anything for a while.  As a result, there are a couple bugs in SkClampRange, marked as such and commented out.  The asserts also weren't quite passing, so I fixed them up (allowing 0xFFFF to be considered either as part of the ramp or part of V1.)

BUG=skia:2481
R=reed@google.com, mtklein@google.com

Author: mtklein@chromium.org

Review URL: https://codereview.chromium.org/260523004

git-svn-id: http://skia.googlecode.com/svn/trunk@14479 2bbb7eff-a529-9590-31e7-b0007b416f81
2014-04-30 16:51:51 +00:00

107 lines
2.8 KiB
C++

/*
* Copyright 2011 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkRandom.h"
#include "Test.h"
#include "gradients/SkClampRange.h"
static skiatest::Reporter* gReporter;
#define R_ASSERT(cond) if (!(cond)) { \
SkDebugf("%d: %s\n", __LINE__, #cond); \
REPORTER_ASSERT(gReporter, cond); \
}
// Arbitrary sentinel values outside [0, 0xFFFF].
static const int kV0 = -42, kV1 = -53, kRamp = -64;
static void check_value(int64_t bigfx, int expected) {
if (bigfx < 0) {
R_ASSERT(expected == kV0);
} else if (bigfx > 0xFFFF) {
R_ASSERT(expected == kV1);
} else if (bigfx == 0xFFFF) {
// Either one is fine (and we do see both).
R_ASSERT(expected == kV1 || expected == kRamp);
} else {
R_ASSERT(expected == kRamp);
}
}
static void slow_check(const SkClampRange& range,
const SkFixed fx, SkFixed dx, int count) {
SkASSERT(range.fCount0 + range.fCount1 + range.fCount2 == count);
// If dx is large, fx will overflow if updated naively. So we use more bits.
int64_t bigfx = fx;
for (int i = 0; i < range.fCount0; i++) {
check_value(bigfx, range.fV0);
bigfx += dx;
}
for (int i = 0; i < range.fCount1; i++) {
check_value(bigfx, kRamp);
bigfx += dx;
}
for (int i = 0; i < range.fCount2; i++) {
check_value(bigfx, range.fV1);
bigfx += dx;
}
}
static void test_range(SkFixed fx, SkFixed dx, int count) {
SkClampRange range;
range.init(fx, dx, count, kV0, kV1);
slow_check(range, fx, dx, count);
}
#define ff(x) SkIntToFixed(x)
DEF_TEST(ClampRange, reporter) {
gReporter = reporter;
test_range(0, 0, 20);
test_range(0xFFFF, 0, 20);
test_range(-ff(2), 0, 20);
test_range( ff(2), 0, 20);
test_range(-10, 1, 20);
test_range(10, -1, 20);
test_range(-10, 3, 20);
test_range(10, -3, 20);
test_range(ff(1), ff(16384), 100);
test_range(ff(-1), ff(-16384), 100);
test_range(ff(1)/2, ff(16384), 100);
// TODO(reed): skia:2481, fix whatever bug this is, then uncomment
//test_range(ff(1)/2, ff(-16384), 100);
SkRandom rand;
// test non-overflow cases
for (int i = 0; i < 1000000; i++) {
SkFixed fx = rand.nextS() >> 1;
SkFixed sx = rand.nextS() >> 1;
int count = rand.nextU() % 1000 + 1;
SkFixed dx = (sx - fx) / count;
test_range(fx, dx, count);
}
// TODO(reed): skia:2481, fix whatever bug this is, then uncomment
/*
// test overflow cases
for (int i = 0; i < 100000; i++) {
SkFixed fx = rand.nextS();
SkFixed dx = rand.nextS();
int count = rand.nextU() % 1000 + 1;
test_range(fx, dx, count);
}
*/
}