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1 /* | |
2 * Copyright (c) 2012, Google Inc. All rights reserved. | |
3 * | |
4 * Redistribution and use in source and binary forms, with or without | |
5 * modification, are permitted provided that the following conditions are | |
6 * met: | |
7 * | |
8 * * Redistributions of source code must retain the above copyright | |
9 * notice, this list of conditions and the following disclaimer. | |
10 * * Redistributions in binary form must reproduce the above | |
11 * copyright notice, this list of conditions and the following disclaimer | |
12 * in the documentation and/or other materials provided with the | |
13 * distribution. | |
14 * * Neither the name of Google Inc. nor the names of its | |
15 * contributors may be used to endorse or promote products derived from | |
16 * this software without specific prior written permission. | |
17 * | |
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR | |
21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT | |
22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | |
23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT | |
24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | |
28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
29 */ | |
30 | |
31 #include "wtf/SaturatedArithmetic.h" | |
32 | |
33 #include "testing/gtest/include/gtest/gtest.h" | |
34 #include <limits.h> | |
35 | |
36 namespace WTF { | |
37 | |
38 TEST(SaturatedArithmeticTest, Addition) { | |
39 EXPECT_EQ(0, saturatedAddition(0, 0)); | |
40 EXPECT_EQ(1, saturatedAddition(0, 1)); | |
41 EXPECT_EQ(100, saturatedAddition(0, 100)); | |
42 EXPECT_EQ(150, saturatedAddition(100, 50)); | |
43 | |
44 EXPECT_EQ(-1, saturatedAddition(0, -1)); | |
45 EXPECT_EQ(0, saturatedAddition(1, -1)); | |
46 EXPECT_EQ(50, saturatedAddition(100, -50)); | |
47 EXPECT_EQ(-50, saturatedAddition(50, -100)); | |
48 | |
49 EXPECT_EQ(INT_MAX - 1, saturatedAddition(INT_MAX - 1, 0)); | |
50 EXPECT_EQ(INT_MAX, saturatedAddition(INT_MAX - 1, 1)); | |
51 EXPECT_EQ(INT_MAX, saturatedAddition(INT_MAX - 1, 2)); | |
52 EXPECT_EQ(INT_MAX - 1, saturatedAddition(0, INT_MAX - 1)); | |
53 EXPECT_EQ(INT_MAX, saturatedAddition(1, INT_MAX - 1)); | |
54 EXPECT_EQ(INT_MAX, saturatedAddition(2, INT_MAX - 1)); | |
55 EXPECT_EQ(INT_MAX, saturatedAddition(INT_MAX - 1, INT_MAX - 1)); | |
56 EXPECT_EQ(INT_MAX, saturatedAddition(INT_MAX, INT_MAX)); | |
57 | |
58 EXPECT_EQ(INT_MIN, saturatedAddition(INT_MIN, 0)); | |
59 EXPECT_EQ(INT_MIN + 1, saturatedAddition(INT_MIN + 1, 0)); | |
60 EXPECT_EQ(INT_MIN + 2, saturatedAddition(INT_MIN + 1, 1)); | |
61 EXPECT_EQ(INT_MIN + 3, saturatedAddition(INT_MIN + 1, 2)); | |
62 EXPECT_EQ(INT_MIN, saturatedAddition(INT_MIN + 1, -1)); | |
63 EXPECT_EQ(INT_MIN, saturatedAddition(INT_MIN + 1, -2)); | |
64 EXPECT_EQ(INT_MIN + 1, saturatedAddition(0, INT_MIN + 1)); | |
65 EXPECT_EQ(INT_MIN, saturatedAddition(-1, INT_MIN + 1)); | |
66 EXPECT_EQ(INT_MIN, saturatedAddition(-2, INT_MIN + 1)); | |
67 | |
68 EXPECT_EQ(INT_MAX / 2 + 10000, saturatedAddition(INT_MAX / 2, 10000)); | |
69 EXPECT_EQ(INT_MAX, saturatedAddition(INT_MAX / 2 + 1, INT_MAX / 2 + 1)); | |
70 EXPECT_EQ(-1, saturatedAddition(INT_MIN, INT_MAX)); | |
71 } | |
72 | |
73 TEST(SaturatedArithmeticTest, Subtraction) { | |
74 EXPECT_EQ(0, saturatedSubtraction(0, 0)); | |
75 EXPECT_EQ(-1, saturatedSubtraction(0, 1)); | |
76 EXPECT_EQ(-100, saturatedSubtraction(0, 100)); | |
77 EXPECT_EQ(50, saturatedSubtraction(100, 50)); | |
78 | |
79 EXPECT_EQ(1, saturatedSubtraction(0, -1)); | |
80 EXPECT_EQ(2, saturatedSubtraction(1, -1)); | |
81 EXPECT_EQ(150, saturatedSubtraction(100, -50)); | |
82 EXPECT_EQ(150, saturatedSubtraction(50, -100)); | |
83 | |
84 EXPECT_EQ(INT_MAX, saturatedSubtraction(INT_MAX, 0)); | |
85 EXPECT_EQ(INT_MAX - 1, saturatedSubtraction(INT_MAX, 1)); | |
86 EXPECT_EQ(INT_MAX - 1, saturatedSubtraction(INT_MAX - 1, 0)); | |
87 EXPECT_EQ(INT_MAX, saturatedSubtraction(INT_MAX - 1, -1)); | |
88 EXPECT_EQ(INT_MAX, saturatedSubtraction(INT_MAX - 1, -2)); | |
89 EXPECT_EQ(-INT_MAX + 1, saturatedSubtraction(0, INT_MAX - 1)); | |
90 EXPECT_EQ(-INT_MAX, saturatedSubtraction(-1, INT_MAX - 1)); | |
91 EXPECT_EQ(-INT_MAX - 1, saturatedSubtraction(-2, INT_MAX - 1)); | |
92 EXPECT_EQ(-INT_MAX - 1, saturatedSubtraction(-3, INT_MAX - 1)); | |
93 | |
94 EXPECT_EQ(INT_MIN, saturatedSubtraction(INT_MIN, 0)); | |
95 EXPECT_EQ(INT_MIN + 1, saturatedSubtraction(INT_MIN + 1, 0)); | |
96 EXPECT_EQ(INT_MIN, saturatedSubtraction(INT_MIN + 1, 1)); | |
97 EXPECT_EQ(INT_MIN, saturatedSubtraction(INT_MIN + 1, 2)); | |
98 | |
99 EXPECT_EQ(0, saturatedSubtraction(INT_MIN, INT_MIN)); | |
100 EXPECT_EQ(0, saturatedSubtraction(INT_MAX, INT_MAX)); | |
101 EXPECT_EQ(INT_MAX, saturatedSubtraction(INT_MAX, INT_MIN)); | |
102 } | |
103 | |
104 TEST(SaturatedArithmeticTest, SetSigned) { | |
105 const int kFractionBits = 6; | |
106 const int intMaxForLayoutUnit = INT_MAX >> kFractionBits; | |
107 const int intMinForLayoutUnit = INT_MIN >> kFractionBits; | |
108 | |
109 EXPECT_EQ(0, saturatedSet<kFractionBits>(0)); | |
110 | |
111 // Internally the max number we can represent (without saturating) | |
112 // is all the (non-sign) bits set except for the bottom n fraction bits | |
113 const int maxInternalRepresentation = INT_MAX ^ ((1 << kFractionBits) - 1); | |
114 EXPECT_EQ(maxInternalRepresentation, | |
115 saturatedSet<kFractionBits>(intMaxForLayoutUnit)); | |
116 | |
117 EXPECT_EQ(getMaxSaturatedSetResultForTesting(kFractionBits), | |
118 saturatedSet<kFractionBits>(intMaxForLayoutUnit + 100)); | |
119 | |
120 EXPECT_EQ((intMaxForLayoutUnit - 100) << kFractionBits, | |
121 saturatedSet<kFractionBits>(intMaxForLayoutUnit - 100)); | |
122 | |
123 EXPECT_EQ(getMinSaturatedSetResultForTesting(kFractionBits), | |
124 saturatedSet<kFractionBits>(intMinForLayoutUnit)); | |
125 | |
126 EXPECT_EQ(getMinSaturatedSetResultForTesting(kFractionBits), | |
127 saturatedSet<kFractionBits>(intMinForLayoutUnit - 100)); | |
128 | |
129 // Shifting negative numbers left has undefined behavior, so use | |
130 // multiplication instead of direct shifting here. | |
131 EXPECT_EQ((intMinForLayoutUnit + 100) * (1 << kFractionBits), | |
132 saturatedSet<kFractionBits>(intMinForLayoutUnit + 100)); | |
133 } | |
134 | |
135 TEST(SaturatedArithmeticTest, SetUnsigned) { | |
136 const int kFractionBits = 6; | |
137 const int intMaxForLayoutUnit = INT_MAX >> kFractionBits; | |
138 | |
139 EXPECT_EQ(0, saturatedSet<kFractionBits>((unsigned)0)); | |
140 | |
141 EXPECT_EQ(getMaxSaturatedSetResultForTesting(kFractionBits), | |
142 saturatedSet<kFractionBits>((unsigned)intMaxForLayoutUnit)); | |
143 | |
144 const unsigned kOverflowed = intMaxForLayoutUnit + 100; | |
145 EXPECT_EQ(getMaxSaturatedSetResultForTesting(kFractionBits), | |
146 saturatedSet<kFractionBits>(kOverflowed)); | |
147 | |
148 const unsigned kNotOverflowed = intMaxForLayoutUnit - 100; | |
149 EXPECT_EQ((intMaxForLayoutUnit - 100) << kFractionBits, | |
150 saturatedSet<kFractionBits>(kNotOverflowed)); | |
151 } | |
152 | |
153 } // namespace WTF | |
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