commit ec7a30cc8688923e0ccfff4c8f81c5e577c4c9ab
author senorblanco@chromium.org <senorblanco@chromium.org@2bbb7eff-a529-9590-31e7-b0007b416f81> Tue Dec 07 21:07:56 2010 +0000
committer senorblanco@chromium.org <senorblanco@chromium.org@2bbb7eff-a529-9590-31e7-b0007b416f81> Tue Dec 07 21:07:56 2010 +0000
tree e91c9784d26105c3dfd24f11df1b6871d41f36cd
parent 038aff623d9fd47946cd31685f74cf473f7c84f0

Upstream mulDiv255Ceil() from WebKit to the skia repository.

(Patch by Noel Gordon (noel.gordon@gmail.com))

Review URL:  http://codereview.appspot.com/3466042



git-svn-id: http://skia.googlecode.com/svn/trunk@632 2bbb7eff-a529-9590-31e7-b0007b416f81

tests/MathTest.cpp

diff --git a/tests/MathTest.cpp b/tests/MathTest.cpp
index 4bfbd94..2555d73 100644
--- a/tests/MathTest.cpp
+++ b/tests/MathTest.cpp
@@ -171,6 +171,19 @@
 #endif
 }
 
+static void test_muldiv255ceiling(skiatest::Reporter* reporter) {
+    for (int c = 0; c <= 255; c++) {
+        for (int a = 0; a <= 255; a++) {
+            int product = (c * a + 255);
+            int expected_ceiling = (product + (product >> 8)) >> 8;
+            int webkit_ceiling = (c * a + 254) / 255;
+            REPORTER_ASSERT(reporter, expected_ceiling == webkit_ceiling);
+            int skia_ceiling = SkMulDiv255Ceiling(c, a);
+            REPORTER_ASSERT(reporter, skia_ceiling == webkit_ceiling);
+        }
+    }
+}
+
 static void test_copysign(skiatest::Reporter* reporter) {
     static const int32_t gTriples[] = {
         // x, y, expected result
@@ -237,6 +250,7 @@
 #endif
 
     test_muldiv255(reporter);
+    test_muldiv255ceiling(reporter);
     test_copysign(reporter);
 
     {