1 files changed, 86 insertions, 0 deletions
diff --git a/tests/ClampRangeTest.cpp b/tests/ClampRangeTest.cpp
new file mode 100644
index 0000000000..b3d1e78a90
--- /dev/null
+++ b/tests/ClampRangeTest.cpp
@@ -0,0 +1,86 @@
+#include "Test.h"
+#include "SkClampRange.h"
+#include "SkRandom.h"
+
+static skiatest::Reporter* gReporter;
+
+static int classify_value(SkFixed fx, int v0, int v1) {
+    if (fx <= 0) {
+        return v0;
+    }
+    if (fx >= 0xFFFF) {
+        return v1;
+    }
+    REPORTER_ASSERT(gReporter, false);
+    return 0;
+}
+
+#define V0  -42
+#define V1  1024
+
+static void slow_check(const SkClampRange& range,
+                       SkFixed fx, SkFixed dx, int count) {
+    SkASSERT(range.fCount0 + range.fCount1 + range.fCount2 == count);
+    
+    int i;
+    for (i = 0; i < range.fCount0; i++) {
+        int v = classify_value(fx, V0, V1);
+        REPORTER_ASSERT(gReporter, v == range.fV0);
+        fx += dx;
+    }
+    REPORTER_ASSERT(gReporter, range.fCount1 == 0 || fx == range.fFx1);
+    for (i = 0; i < range.fCount1; i++) {
+        REPORTER_ASSERT(gReporter, fx >= 0 && fx <= 0xFFFF);
+        fx += dx;
+    }
+    for (i = 0; i < range.fCount2; i++) {
+        int v = classify_value(fx, V0, V1);
+        REPORTER_ASSERT(gReporter, v == range.fV1);
+        fx += dx;
+    }
+}
+
+static void test_range(SkFixed fx, SkFixed dx, int count) {
+    SkClampRange range;
+    range.init(fx, dx, count, V0, V1);
+    slow_check(range, fx, dx, count);
+}
+
+#define ff(x)   SkIntToFixed(x)
+
+static void TestClampRange(skiatest::Reporter* 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);
+    
+    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);
+    }
+    
+    // test overflow cases
+    for (int i = 0; i < 0*1000000; i++) {
+        SkFixed fx = rand.nextS();
+        SkFixed sx = rand.nextS();
+        int count = rand.nextU() % 1000 + 1;
+        SkFixed dx = (sx - fx) / count;
+        test_range(fx, dx, count);
+    }
+}
+
+#include "TestClassDef.h"
+DEFINE_TESTCLASS("ClampRange", ClampRangeClass, TestClampRange)