components/packed_ct_ev_whitelist/bit_stream_reader_unittest.cc

   1 // Copyright 2014 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 "components/packed_ct_ev_whitelist/bit_stream_reader.h"
   6
   7 #include <algorithm>
   8 #include <string>
   9
  10 #include "testing/gtest/include/gtest/gtest.h"
  11
  12 namespace packed_ct_ev_whitelist {
  13 namespace internal {
  14
  15 const uint8_t kSomeData[] = {0xd5, 0xe2, 0xaf, 0xe5, 0xbb, 0x10, 0x7c, 0xd1};
  16
  17 TEST(BitStreamReaderTest, CanReadSingleByte) {
  18   BitStreamReader reader(
  19       base::StringPiece(reinterpret_cast<const char*>(kSomeData), 1));
  20   uint64_t v(0);
  21
  22   EXPECT_EQ(8u, reader.BitsLeft());
  23   EXPECT_TRUE(reader.ReadBits(8, &v));
  24   EXPECT_EQ(UINT64_C(0xd5), v);
  25
  26   EXPECT_FALSE(reader.ReadBits(1, &v));
  27   EXPECT_EQ(0u, reader.BitsLeft());
  28 }
  29
  30 TEST(BitStreamReaderTest, CanReadSingleBits) {
  31   const uint64_t expected_bits[] = {
  32       1, 1, 0, 1, 0, 1, 0, 1, 1, 1, 1, 0, 0, 0, 1, 0};
  33   BitStreamReader reader(
  34       base::StringPiece(reinterpret_cast<const char*>(kSomeData), 2));
  35   EXPECT_EQ(16u, reader.BitsLeft());
  36   uint64_t v(0);
  37
  38   for (int i = 0; i < 16; ++i) {
  39     EXPECT_TRUE(reader.ReadBits(1, &v));
  40     EXPECT_EQ(expected_bits[i], v);
  41   }
  42   EXPECT_EQ(0u, reader.BitsLeft());
  43 }
  44
  45 TEST(BitStreamReaderTest, CanReadBitGroups) {
  46   BitStreamReader reader(
  47       base::StringPiece(reinterpret_cast<const char*>(kSomeData), 3));
  48   EXPECT_EQ(24u, reader.BitsLeft());
  49   uint64_t v(0);
  50   uint64_t res(0);
  51
  52   EXPECT_TRUE(reader.ReadBits(5, &v));
  53   res |= v << 19;
  54   EXPECT_EQ(19u, reader.BitsLeft());
  55   EXPECT_TRUE(reader.ReadBits(13, &v));
  56   res |= v << 6;
  57   EXPECT_EQ(6u, reader.BitsLeft());
  58   EXPECT_TRUE(reader.ReadBits(6, &v));
  59   res |= v;
  60   EXPECT_EQ(UINT64_C(0xd5e2af), res);
  61
  62   EXPECT_FALSE(reader.ReadBits(1, &v));
  63 }
  64
  65 TEST(BitStreamReaderTest, CanRead64Bit) {
  66   BitStreamReader reader(
  67       base::StringPiece(reinterpret_cast<const char*>(kSomeData), 8));
  68   EXPECT_EQ(64u, reader.BitsLeft());
  69   uint64_t v(0);
  70
  71   EXPECT_TRUE(reader.ReadBits(64, &v));
  72   EXPECT_EQ(UINT64_C(0xd5e2afe5bb107cd1), v);
  73 }
  74
  75 TEST(BitStreamReaderTest, CanReadUnaryEncodedNumbers) {
  76   internal::BitStreamReader reader(
  77       base::StringPiece(reinterpret_cast<const char*>(kSomeData), 3));
  78   const uint64_t expected_values[] = {2, 1, 1, 4, 0, 0, 1, 1, 1, 4};
  79   uint64_t v(0);
  80   for (int i = 0; i < 10; ++i) {
  81     EXPECT_TRUE(reader.ReadUnaryEncoding(&v));
  82     EXPECT_EQ(expected_values[i], v) << "Values differ at position " << i;
  83   }
  84 }
  85
  86 TEST(BitStreamReaderTest, CannotReadFromEmptyStream) {
  87   BitStreamReader reader(base::StringPiece(
  88       reinterpret_cast<const char*>(kSomeData), static_cast<size_t>(0u)));
  89   uint64_t v(0);
  90
  91   EXPECT_EQ(0u, reader.BitsLeft());
  92   EXPECT_FALSE(reader.ReadBits(1, &v));
  93   EXPECT_FALSE(reader.ReadUnaryEncoding(&v));
  94 }
  95
  96 }  // namespace internal
  97 }  // namespace packed_ct_ev_whitelist