// Copyright 2013 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.

// The test buffer data is 52 bytes, wrap position is set to 20 (this is
// arbitrarily chosen). The total buffer size is allocated dynamically based on
// the actual header size. This gives:
// Header of some size, non-wrapping part 20 bytes, wrapping part 32 bytes.
// As input data, a 14 byte array is used and repeatedly written. It's chosen
// not to be an integer factor smaller than the wrapping part. This ensures that
// the wrapped data isn't repeated at the same position.
// Note that desipte the number of wraps (if one or more), the reference output
// data is the same since the offset at each wrap is always the same.

#include "chrome/common/partial_circular_buffer.h"

#include <stddef.h>
#include <stdint.h>

#include <memory>

#include "base/macros.h"
#include "testing/gtest/include/gtest/gtest.h"

const uint32_t kWrapPosition = 20;
const uint8_t kInputData[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14};
const uint8_t kOutputRefDataWrap[] =
    // The 20 bytes in the non-wrapping part.
    {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 1, 2, 3, 4, 5, 6,
     // The 32 bytes in wrapping part.
     11, 12, 13, 14, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 1, 2, 3, 4,
     5, 6, 7, 8, 9, 10, 11, 12, 13, 14};

class PartialCircularBufferTest : public testing::Test {
 public:
  PartialCircularBufferTest() {
    PartialCircularBuffer::BufferData test_struct;
    buffer_header_size_ =
        &test_struct.data[0] - reinterpret_cast<uint8_t*>(&test_struct);

    buffer_.reset(
        new uint8_t[buffer_header_size_ + sizeof(kOutputRefDataWrap)]);
  }

  void InitWriteBuffer(bool append) {
    pcb_write_.reset(new PartialCircularBuffer(
        buffer_.get(),
        buffer_header_size_ + sizeof(kOutputRefDataWrap),
        kWrapPosition,
        append));
  }

  void WriteToBuffer(int num) {
    for (int i = 0; i < num; ++i)
      pcb_write_->Write(kInputData, sizeof(kInputData));
  }

  void InitReadBuffer() {
    pcb_read_.reset(new PartialCircularBuffer(
        buffer_.get(), buffer_header_size_ + sizeof(kOutputRefDataWrap)));
  }

 protected:
  std::unique_ptr<PartialCircularBuffer> pcb_write_;
  std::unique_ptr<PartialCircularBuffer> pcb_read_;
  std::unique_ptr<uint8_t[]> buffer_;
  uint32_t buffer_header_size_;

  DISALLOW_COPY_AND_ASSIGN(PartialCircularBufferTest);
};

TEST_F(PartialCircularBufferTest, NoWrapBeginningPartOnly) {
  InitWriteBuffer(false);
  WriteToBuffer(1);
  InitReadBuffer();

  uint8_t output_data[sizeof(kInputData)] = {0};
  EXPECT_EQ(sizeof(output_data),
            pcb_read_->Read(output_data, sizeof(output_data)));

  EXPECT_EQ(0, memcmp(kInputData, output_data, sizeof(kInputData)));

  EXPECT_EQ(0u, pcb_read_->Read(output_data, sizeof(output_data)));
}

TEST_F(PartialCircularBufferTest, NoWrapBeginningAndEndParts) {
  InitWriteBuffer(false);
  WriteToBuffer(2);
  InitReadBuffer();

  uint8_t output_data[2 * sizeof(kInputData)] = {0};
  EXPECT_EQ(sizeof(output_data),
            pcb_read_->Read(output_data, sizeof(output_data)));

  const uint8_t output_ref_data[2 * sizeof(kInputData)] = {
      1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
      1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14};
  EXPECT_EQ(0, memcmp(output_ref_data, output_data, sizeof(output_data)));

  EXPECT_EQ(0u, pcb_read_->Read(output_data, sizeof(output_data)));
}

TEST_F(PartialCircularBufferTest, WrapOnce) {
  InitWriteBuffer(false);
  WriteToBuffer(4);
  InitReadBuffer();

  uint8_t output_data[sizeof(kOutputRefDataWrap)] = {0};
  EXPECT_EQ(sizeof(output_data),
            pcb_read_->Read(output_data, sizeof(output_data)));

  EXPECT_EQ(0, memcmp(kOutputRefDataWrap, output_data, sizeof(output_data)));

  EXPECT_EQ(0u, pcb_read_->Read(output_data, sizeof(output_data)));
}

TEST_F(PartialCircularBufferTest, WrapTwice) {
  InitWriteBuffer(false);
  WriteToBuffer(7);
  InitReadBuffer();

  uint8_t output_data[sizeof(kOutputRefDataWrap)] = {0};
  EXPECT_EQ(sizeof(output_data),
            pcb_read_->Read(output_data, sizeof(output_data)));

  EXPECT_EQ(0, memcmp(kOutputRefDataWrap, output_data, sizeof(output_data)));

  EXPECT_EQ(0u, pcb_read_->Read(output_data, sizeof(output_data)));
}

TEST_F(PartialCircularBufferTest, WrapOnceSmallerOutputBuffer) {
  InitWriteBuffer(false);
  WriteToBuffer(4);
  InitReadBuffer();

  uint8_t output_data[sizeof(kOutputRefDataWrap)] = {0};
  const uint32_t size_per_read = 16;
  uint32_t read = 0;
  for (; read + size_per_read <= sizeof(output_data); read += size_per_read) {
    EXPECT_EQ(size_per_read,
              pcb_read_->Read(output_data + read, size_per_read));
  }
  EXPECT_EQ(sizeof(output_data) - read,
            pcb_read_->Read(output_data + read, size_per_read));

  EXPECT_EQ(0, memcmp(kOutputRefDataWrap, output_data, sizeof(output_data)));

  EXPECT_EQ(0u, pcb_read_->Read(output_data, sizeof(output_data)));
}

TEST_F(PartialCircularBufferTest, WrapOnceWithAppend) {
  InitWriteBuffer(false);
  WriteToBuffer(2);
  InitWriteBuffer(true);
  WriteToBuffer(2);
  InitReadBuffer();

  uint8_t output_data[sizeof(kOutputRefDataWrap)] = {0};
  EXPECT_EQ(sizeof(output_data),
            pcb_read_->Read(output_data, sizeof(output_data)));

  EXPECT_EQ(0, memcmp(kOutputRefDataWrap, output_data, sizeof(output_data)));

  EXPECT_EQ(0u, pcb_read_->Read(output_data, sizeof(output_data)));
}

TEST_F(PartialCircularBufferTest, WrapTwiceWithAppend) {
  InitWriteBuffer(false);
  WriteToBuffer(4);
  InitWriteBuffer(true);
  WriteToBuffer(3);
  InitReadBuffer();

  uint8_t output_data[sizeof(kOutputRefDataWrap)] = {0};
  EXPECT_EQ(sizeof(output_data),
            pcb_read_->Read(output_data, sizeof(output_data)));

  EXPECT_EQ(0, memcmp(kOutputRefDataWrap, output_data, sizeof(output_data)));

  EXPECT_EQ(0u, pcb_read_->Read(output_data, sizeof(output_data)));
}

TEST_F(PartialCircularBufferTest, WrapOnceThenOverwriteWithNoWrap) {
  InitWriteBuffer(false);
  WriteToBuffer(4);
  InitWriteBuffer(false);
  WriteToBuffer(1);
  InitReadBuffer();

  uint8_t output_data[sizeof(kInputData)] = {0};
  EXPECT_EQ(sizeof(output_data),
            pcb_read_->Read(output_data, sizeof(output_data)));

  EXPECT_EQ(0, memcmp(kInputData, output_data, sizeof(kInputData)));

  EXPECT_EQ(0u, pcb_read_->Read(output_data, sizeof(output_data)));
}

TEST_F(PartialCircularBufferTest, WrapTwiceWithSingleWrite) {
  const size_t kInputSize = sizeof(kInputData);
  const size_t kLargeSize = kInputSize * 7;
  uint8_t large_input[kLargeSize] = {0};
  for (size_t offset = 0; offset < kLargeSize; offset += kInputSize)
    memcpy(large_input + offset, kInputData, kInputSize);

  InitWriteBuffer(false);
  pcb_write_->Write(large_input, kLargeSize);
  InitReadBuffer();

  uint8_t output_data[sizeof(kOutputRefDataWrap)] = {0};
  EXPECT_EQ(sizeof(output_data),
            pcb_read_->Read(output_data, sizeof(output_data)));

  EXPECT_EQ(0, memcmp(kOutputRefDataWrap, output_data, sizeof(output_data)));

  EXPECT_EQ(0u, pcb_read_->Read(output_data, sizeof(output_data)));
}