SkHalfToFloat_01 / SkFloatToHalf_01

tests/Float16Test.cpp

 /*
  * Copyright 2016 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 "SkColor.h"
 #include "SkHalf.h"
 #include "SkOpts.h"
 #include "SkPixmap.h"
+#include "SkRandom.h"
 
 static bool eq_within_half_float(float a, float b) {
     const float kTolerance = 1.0f / (1 << (8 + 10));
 
     SkHalf ha = SkFloatToHalf(a);
     SkHalf hb = SkFloatToHalf(b);
     float a2 = SkHalfToFloat(ha);
     float b2 = SkHalfToFloat(hb);
     return fabsf(a2 - b2) <= kTolerance;
 }
@@ skipping 34 matching lines @@
     const uint16_t hs[] = { 0x3c00, 0x4000, 0x4200, 0x4400, 0x4500, 0x4600, 0x4700 };
 
     uint16_t hscratch[7];
     SkOpts::float_to_half(hscratch, fs, 7);
     REPORTER_ASSERT(reporter, 0 == memcmp(hscratch, hs, sizeof(hs)));
 
     float fscratch[7];
     SkOpts::half_to_float(fscratch, hs, 7);
     REPORTER_ASSERT(reporter, 0 == memcmp(fscratch, fs, sizeof(fs)));
 }
+
+DEF_TEST(HalfToFloat_01, r) {
+    for (uint16_t h = 0; h < 0x8000; h++) {
+        float f = SkHalfToFloat(h);
+        if (f >= 0 && f <= 1) {
+            REPORTER_ASSERT(r, SkHalfToFloat_01(h)[0] == f);
+            REPORTER_ASSERT(r, SkFloatToHalf_01(SkHalfToFloat_01(h)) == h);
+        }
+    }
+}
+
+DEF_TEST(FloatToHalf_01, r) {
+#if 0
+    for (uint32_t bits = 0; bits < 0x80000000; bits++) {
+#else
+    SkRandom rand;
+    for (int i = 0; i < 1000000; i++) {
+        uint32_t bits = rand.nextU();
+#endif
+        float f;
+        memcpy(&f, &bits, 4);
+        if (f >= 0 && f <= 1) {
+            uint16_t h1 = (uint16_t)SkFloatToHalf_01(Sk4f(f,0,0,0)),
+                     h2 = SkFloatToHalf(f);
+            bool ok = (h1 == h2 || h1 == h2-1);
+            REPORTER_ASSERT(r, ok);
+            if (!ok) {
+                SkDebugf("%08x (%d) -> %04x (%d), want %04x (%d)\n",
+                         bits, bits>>23, h1, h1>>10, h2, h2>>10);
+                break;
+            }
+        }
+    }
+}