/* vim:set ts=2 sw=2 sts=2 et cindent: */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#if !defined(BufferMediaResource_h_)

#define BufferMediaResource_h_

#include "MediaResource.h"

#include "nsISeekableStream.h"

#include <algorithm>

namespace mozilla {

DDLoggedTypeDeclNameAndBase(BufferMediaResource, MediaResource);

// A simple MediaResource based on an in memory buffer.  This class accepts

// the address and the length of the buffer, and simulates a read/seek API

// on top of it.  The Read implementation involves copying memory, which is

// unfortunate, but the MediaResource interface mandates that.

class BufferMediaResource

  : public MediaResource

  , public DecoderDoctorLifeLogger<BufferMediaResource>

{

public:

  BufferMediaResource(const uint8_t* aBuffer, uint32_t aLength)

    : mBuffer(aBuffer)

    , mLength(aLength)

  {

  }

protected:

  virtual ~BufferMediaResource()

  {

  }

private:

  // These methods are called off the main thread.

  nsresult ReadAt(int64_t aOffset, char* aBuffer,

                  uint32_t aCount, uint32_t* aBytes) override

  {

    if (aOffset < 0 || aOffset > mLength) {

      return NS_ERROR_FAILURE;

    }

    *aBytes = std::min(mLength - static_cast<uint32_t>(aOffset), aCount);

    memcpy(aBuffer, mBuffer + aOffset, *aBytes);

    return NS_OK;

  }

  // Memory-based and no locks, caching discouraged.

  bool ShouldCacheReads() override { return false; }

  void Pin() override {}

  void Unpin() override {}

  int64_t GetLength() override { return mLength; }

  int64_t GetNextCachedData(int64_t aOffset) override { return aOffset; }

  int64_t GetCachedDataEnd(int64_t aOffset) override

  {

    return std::max(aOffset, int64_t(mLength));

  }

  bool IsDataCachedToEndOfResource(int64_t aOffset) override { return true; }

  nsresult ReadFromCache(char* aBuffer,

                         int64_t aOffset,

                         uint32_t aCount) override

  {

    if (aOffset < 0) {

      return NS_ERROR_FAILURE;

    }

    uint32_t bytes = std::min(mLength - static_cast<uint32_t>(aOffset), aCount);

    memcpy(aBuffer, mBuffer + aOffset, bytes);

    return NS_OK;

  }

  nsresult GetCachedRanges(MediaByteRangeSet& aRanges) override

  {

    aRanges += MediaByteRange(0, int64_t(mLength));

    return NS_OK;

  }

private:

  const uint8_t * mBuffer;

  uint32_t mLength;

};

} // namespace mozilla

#endif