Fix founding difference in pdfium_test on AdobeCMYK_to_sRGB

core/fxcodec/codec/fx_codec_jpx_unittest.cpp

 // Copyright 2014 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <stdint.h>
 
 #include <limits>
 
 #include "core/fxcodec/codec/codec_int.h"
 #include "testing/fx_string_testhelpers.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 static const OPJ_OFF_T kSkipError = static_cast<OPJ_OFF_T>(-1);
 static const OPJ_SIZE_T kReadError = static_cast<OPJ_SIZE_T>(-1);
 static const OPJ_SIZE_T kWriteError = static_cast<OPJ_SIZE_T>(-1);
 
 static unsigned char stream_data[] = {
     0x00, 0x01, 0x02, 0x03,
     0x84, 0x85, 0x86, 0x87,  // Include some hi-bytes, too.
 };
 
+union Float_t {
+  Float_t(float num = 0.0f) : f(num) {}
+
+  int32_t i;
+  FX_FLOAT f;
+};
+
+TEST(fxcodec, CMYK_Rounding) {
+  // Testing all floats from 0.0 to 1.0 takes about 35 seconds in release
+  // builds and much longer in debug builds, so just test the known-dangerous
+  // range.
+  const FX_FLOAT startValue = 0.001f;
+  const FX_FLOAT endValue = 0.003f;
+  FX_FLOAT R = 0.0f, G = 0.0f, B = 0.0f;
+  // Iterate through floats by incrementing the representation, as discussed in
+  // https://randomascii.wordpress.com/2012/01/23/stupid-float-tricks-2/
+  for (Float_t f = startValue; f.f < endValue; f.i++) {
+    AdobeCMYK_to_sRGB(f.f, f.f, f.f, f.f, R, G, B);
+  }
+  // Check various other 'special' numbers.
+  AdobeCMYK_to_sRGB(0.0f, 0.25f, 0.5f, 1.0f, R, G, B);
+}
+
 TEST(fxcodec, DecodeDataNullDecodeData) {
   unsigned char buffer[16];
   DecodeData* ptr = nullptr;
 
   // Error codes, not segvs, should callers pass us a nullptr pointer.
   EXPECT_EQ(kReadError, opj_read_from_memory(buffer, sizeof(buffer), ptr));
   EXPECT_EQ(kWriteError, opj_write_from_memory(buffer, sizeof(buffer), ptr));
   EXPECT_EQ(kSkipError, opj_skip_from_memory(1, ptr));
   EXPECT_FALSE(opj_seek_from_memory(1, ptr));
 }
@@ skipping 491 matching lines @@
       EXPECT_NE(img.comps[0].h, img.comps[1].h);
       EXPECT_NE(img.comps[0].w, img.comps[2].w);
       EXPECT_NE(img.comps[0].h, img.comps[2].h);
     }
     FX_Free(img.comps[0].data);
     FX_Free(img.comps[1].data);
     FX_Free(img.comps[2].data);
   }
   FX_Free(img.comps);
 }