big_endian_unittest.cc

// Copyright 2014 The Chromium 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 "base/big_endian.h"

#include "base/strings/string_piece.h"
#include "testing/gtest/include/gtest/gtest.h"

namespace base {

TEST(BigEndianReaderTest, ReadsValues) {
  char data[] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0xA, 0xB, 0xC, 0xD, 0xE, 0xF,
                  0x1A, 0x2B, 0x3C, 0x4D, 0x5E };
  char buf[2];
  uint8 u8;
  uint16 u16;
  uint32 u32;
  uint64 u64;
  base::StringPiece piece;
  BigEndianReader reader(data, sizeof(data));

  EXPECT_TRUE(reader.Skip(2));
  EXPECT_EQ(data + 2, reader.ptr());
  EXPECT_EQ(reader.remaining(), static_cast<int>(sizeof(data)) - 2);
  EXPECT_TRUE(reader.ReadBytes(buf, sizeof(buf)));
  EXPECT_EQ(0x2, buf[0]);
  EXPECT_EQ(0x3, buf[1]);
  EXPECT_TRUE(reader.ReadU8(&u8));
  EXPECT_EQ(0x4, u8);
  EXPECT_TRUE(reader.ReadU16(&u16));
  EXPECT_EQ(0x0506, u16);
  EXPECT_TRUE(reader.ReadU32(&u32));
  EXPECT_EQ(0x0708090Au, u32);
  EXPECT_TRUE(reader.ReadU64(&u64));
  EXPECT_EQ(0x0B0C0D0E0F1A2B3Cllu, u64);
  base::StringPiece expected(reader.ptr(), 2);
  EXPECT_TRUE(reader.ReadPiece(&piece, 2));
  EXPECT_EQ(2u, piece.size());
  EXPECT_EQ(expected.data(), piece.data());
}

TEST(BigEndianReaderTest, RespectsLength) {
  char data[8];
  char buf[2];
  uint8 u8;
  uint16 u16;
  uint32 u32;
  uint64 u64;
  base::StringPiece piece;
  BigEndianReader reader(data, sizeof(data));
  // 8 left
  EXPECT_FALSE(reader.Skip(9));
  EXPECT_TRUE(reader.Skip(1));
  // 7 left
  EXPECT_FALSE(reader.ReadU64(&u64));
  EXPECT_TRUE(reader.Skip(4));
  // 3 left
  EXPECT_FALSE(reader.ReadU32(&u32));
  EXPECT_FALSE(reader.ReadPiece(&piece, 4));
  EXPECT_TRUE(reader.Skip(2));
  // 1 left
  EXPECT_FALSE(reader.ReadU16(&u16));
  EXPECT_FALSE(reader.ReadBytes(buf, 2));
  EXPECT_TRUE(reader.Skip(1));
  // 0 left
  EXPECT_FALSE(reader.ReadU8(&u8));
  EXPECT_EQ(0, reader.remaining());
}

TEST(BigEndianWriterTest, WritesValues) {
  char expected[] = { 0, 0, 2, 3, 4, 5, 6, 7, 8, 9, 0xA, 0xB, 0xC, 0xD, 0xE,
                      0xF, 0x1A, 0x2B, 0x3C };
  char data[sizeof(expected)];
  char buf[] = { 0x2, 0x3 };
  memset(data, 0, sizeof(data));
  BigEndianWriter writer(data, sizeof(data));

  EXPECT_TRUE(writer.Skip(2));
  EXPECT_TRUE(writer.WriteBytes(buf, sizeof(buf)));
  EXPECT_TRUE(writer.WriteU8(0x4));
  EXPECT_TRUE(writer.WriteU16(0x0506));
  EXPECT_TRUE(writer.WriteU32(0x0708090A));
  EXPECT_TRUE(writer.WriteU64(0x0B0C0D0E0F1A2B3Cllu));
  EXPECT_EQ(0, memcmp(expected, data, sizeof(expected)));
}

TEST(BigEndianWriterTest, RespectsLength) {
  char data[8];
  char buf[2];
  uint8 u8 = 0;
  uint16 u16 = 0;
  uint32 u32 = 0;
  uint64 u64 = 0;
  BigEndianWriter writer(data, sizeof(data));
  // 8 left
  EXPECT_FALSE(writer.Skip(9));
  EXPECT_TRUE(writer.Skip(1));
  // 7 left
  EXPECT_FALSE(writer.WriteU64(u64));
  EXPECT_TRUE(writer.Skip(4));
  // 3 left
  EXPECT_FALSE(writer.WriteU32(u32));
  EXPECT_TRUE(writer.Skip(2));
  // 1 left
  EXPECT_FALSE(writer.WriteU16(u16));
  EXPECT_FALSE(writer.WriteBytes(buf, 2));
  EXPECT_TRUE(writer.Skip(1));
  // 0 left
  EXPECT_FALSE(writer.WriteU8(u8));
  EXPECT_EQ(0, writer.remaining());
}

}  // namespace base