net/quic/quic_data_writer_test.cc

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