1// Copyright (c) 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "net/quic/quic_data_writer.h"
6
7#include "base/memory/scoped_ptr.h"
8#include "net/quic/quic_data_reader.h"
9#include "net/test/gtest_util.h"
10#include "testing/gtest/include/gtest/gtest.h"
11
12namespace net {
13namespace test {
14namespace {
15
16TEST(QuicDataWriterTest, WriteUInt8ToOffset) {
17  QuicDataWriter writer(4);
18
19  writer.WriteUInt32(0xfefdfcfb);
20  EXPECT_TRUE(writer.WriteUInt8ToOffset(1, 0));
21  EXPECT_TRUE(writer.WriteUInt8ToOffset(2, 1));
22  EXPECT_TRUE(writer.WriteUInt8ToOffset(3, 2));
23  EXPECT_TRUE(writer.WriteUInt8ToOffset(4, 3));
24
25  scoped_ptr<char[]> data(writer.take());
26
27  EXPECT_EQ(1, data[0]);
28  EXPECT_EQ(2, data[1]);
29  EXPECT_EQ(3, data[2]);
30  EXPECT_EQ(4, data[3]);
31}
32
33TEST(QuicDataWriterDeathTest, WriteUInt8ToOffset) {
34  QuicDataWriter writer(4);
35
36  EXPECT_DFATAL(EXPECT_FALSE(writer.WriteUInt8ToOffset(5, 4)),
37                "offset: 4 >= capacity: 4");
38}
39
40TEST(QuicDataWriterTest, SanityCheckUFloat16Consts) {
41  // Check the arithmetic on the constants - otherwise the values below make
42  // no sense.
43  EXPECT_EQ(30, kUFloat16MaxExponent);
44  EXPECT_EQ(11, kUFloat16MantissaBits);
45  EXPECT_EQ(12, kUFloat16MantissaEffectiveBits);
46  EXPECT_EQ(GG_UINT64_C(0x3FFC0000000), kUFloat16MaxValue);
47}
48
49TEST(QuicDataWriterTest, WriteUFloat16) {
50  struct TestCase {
51    uint64 decoded;
52    uint16 encoded;
53  };
54  TestCase test_cases[] = {
55    // Small numbers represent themselves.
56    { 0, 0 }, { 1, 1 }, { 2, 2 }, { 3, 3 }, { 4, 4 }, { 5, 5 }, { 6, 6 },
57    { 7, 7 }, { 15, 15 }, { 31, 31 }, { 42, 42 }, { 123, 123 }, { 1234, 1234 },
58    // Check transition through 2^11.
59    { 2046, 2046 }, { 2047, 2047 }, { 2048, 2048 }, { 2049, 2049 },
60    // Running out of mantissa at 2^12.
61    { 4094, 4094 }, { 4095, 4095 }, { 4096, 4096 }, { 4097, 4096 },
62    { 4098, 4097 }, { 4099, 4097 }, { 4100, 4098 }, { 4101, 4098 },
63    // Check transition through 2^13.
64    { 8190, 6143 }, { 8191, 6143 }, { 8192, 6144 }, { 8193, 6144 },
65    { 8194, 6144 }, { 8195, 6144 }, { 8196, 6145 }, { 8197, 6145 },
66    // Half-way through the exponents.
67    { 0x7FF8000, 0x87FF }, { 0x7FFFFFF, 0x87FF }, { 0x8000000, 0x8800 },
68    { 0xFFF0000, 0x8FFF }, { 0xFFFFFFF, 0x8FFF }, { 0x10000000, 0x9000 },
69    // Transition into the largest exponent.
70    { 0x1FFFFFFFFFE, 0xF7FF}, { 0x1FFFFFFFFFF, 0xF7FF},
71    { 0x20000000000, 0xF800}, { 0x20000000001, 0xF800},
72    { 0x2003FFFFFFE, 0xF800}, { 0x2003FFFFFFF, 0xF800},
73    { 0x20040000000, 0xF801}, { 0x20040000001, 0xF801},
74    // Transition into the max value and clamping.
75    { 0x3FF80000000, 0xFFFE}, { 0x3FFBFFFFFFF, 0xFFFE},
76    { 0x3FFC0000000, 0xFFFF}, { 0x3FFC0000001, 0xFFFF},
77    { 0x3FFFFFFFFFF, 0xFFFF}, { 0x40000000000, 0xFFFF},
78    { 0xFFFFFFFFFFFFFFFF, 0xFFFF},
79  };
80  int num_test_cases = sizeof(test_cases) / sizeof(test_cases[0]);
81
82  for (int i = 0; i < num_test_cases; ++i) {
83    QuicDataWriter writer(2);
84    EXPECT_TRUE(writer.WriteUFloat16(test_cases[i].decoded));
85    scoped_ptr<char[]> data(writer.take());
86    EXPECT_EQ(test_cases[i].encoded, *reinterpret_cast<uint16*>(data.get()));
87  }
88}
89
90TEST(QuicDataWriterTest, ReadUFloat16) {
91  struct TestCase {
92    uint64 decoded;
93    uint16 encoded;
94  };
95  TestCase test_cases[] = {
96    // There are fewer decoding test cases because encoding truncates, and
97    // decoding returns the smallest expansion.
98    // Small numbers represent themselves.
99    { 0, 0 }, { 1, 1 }, { 2, 2 }, { 3, 3 }, { 4, 4 }, { 5, 5 }, { 6, 6 },
100    { 7, 7 }, { 15, 15 }, { 31, 31 }, { 42, 42 }, { 123, 123 }, { 1234, 1234 },
101    // Check transition through 2^11.
102    { 2046, 2046 }, { 2047, 2047 }, { 2048, 2048 }, { 2049, 2049 },
103    // Running out of mantissa at 2^12.
104    { 4094, 4094 }, { 4095, 4095 }, { 4096, 4096 },
105    { 4098, 4097 }, { 4100, 4098 },
106    // Check transition through 2^13.
107    { 8190, 6143 }, { 8192, 6144 }, { 8196, 6145 },
108    // Half-way through the exponents.
109    { 0x7FF8000, 0x87FF }, { 0x8000000, 0x8800 },
110    { 0xFFF0000, 0x8FFF }, { 0x10000000, 0x9000 },
111    // Transition into the largest exponent.
112    { 0x1FFE0000000, 0xF7FF}, { 0x20000000000, 0xF800},
113    { 0x20040000000, 0xF801},
114    // Transition into the max value.
115    { 0x3FF80000000, 0xFFFE}, { 0x3FFC0000000, 0xFFFF},
116  };
117  int num_test_cases = sizeof(test_cases) / sizeof(test_cases[0]);
118
119  for (int i = 0; i < num_test_cases; ++i) {
120    QuicDataReader reader(reinterpret_cast<char*>(&test_cases[i].encoded), 2);
121    uint64 value;
122    EXPECT_TRUE(reader.ReadUFloat16(&value));
123    EXPECT_EQ(test_cases[i].decoded, value);
124  }
125}
126
127TEST(QuicDataWriterTest, RoundTripUFloat16) {
128  // Just test all 16-bit encoded values. 0 and max already tested above.
129  uint64 previous_value = 0;
130  for (uint16 i = 1; i < 0xFFFF; ++i) {
131    // Read the two bytes.
132    QuicDataReader reader(reinterpret_cast<char*>(&i), 2);
133    uint64 value;
134    // All values must be decodable.
135    EXPECT_TRUE(reader.ReadUFloat16(&value));
136    // Check that small numbers represent themselves
137    if (i < 4097)
138      EXPECT_EQ(i, value);
139    // Check there's monotonic growth.
140    EXPECT_LT(previous_value, value);
141    // Check that precision is within 0.5% away from the denormals.
142    if (i > 2000)
143      EXPECT_GT(previous_value * 1005, value * 1000);
144    // Check we're always within the promised range.
145    EXPECT_LT(value, GG_UINT64_C(0x3FFC0000000));
146    previous_value = value;
147    QuicDataWriter writer(6);
148    EXPECT_TRUE(writer.WriteUFloat16(value - 1));
149    EXPECT_TRUE(writer.WriteUFloat16(value));
150    EXPECT_TRUE(writer.WriteUFloat16(value + 1));
151    scoped_ptr<char[]> data(writer.take());
152    // Check minimal decoding (previous decoding has previous encoding).
153    EXPECT_EQ(i-1, *reinterpret_cast<uint16*>(data.get()));
154    // Check roundtrip.
155    EXPECT_EQ(i, *reinterpret_cast<uint16*>(data.get() + 2));
156    // Check next decoding.
157    EXPECT_EQ(i < 4096? i+1 : i, *reinterpret_cast<uint16*>(data.get() + 4));
158  }
159}
160
161}  // namespace
162}  // namespace test
163}  // namespace net
164