/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim: set ts=8 sts=2 et sw=2 tw=80: */

/* 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/. */

#include "BlobImpl.h"

#include "File.h"

#include "mozilla/CheckedInt.h"

namespace mozilla {

namespace dom {

// Makes sure that aStart and aEnd is less then or equal to aSize and greater

// than 0

static void

ParseSize(int64_t aSize, int64_t& aStart, int64_t& aEnd)

{

  CheckedInt64 newStartOffset = aStart;

  if (aStart < -aSize) {

    newStartOffset = 0;

  }

  else if (aStart < 0) {

    newStartOffset += aSize;

  }

  else if (aStart > aSize) {

    newStartOffset = aSize;

  }

  CheckedInt64 newEndOffset = aEnd;

  if (aEnd < -aSize) {

    newEndOffset = 0;

  }

  else if (aEnd < 0) {

    newEndOffset += aSize;

  }

  else if (aEnd > aSize) {

    newEndOffset = aSize;

  }

  if (!newStartOffset.isValid() || !newEndOffset.isValid() ||

      newStartOffset.value() >= newEndOffset.value()) {

    aStart = aEnd = 0;

  }

  else {

    aStart = newStartOffset.value();

    aEnd = newEndOffset.value();

  }

}

already_AddRefed<BlobImpl>

BlobImpl::Slice(const Optional<int64_t>& aStart,

                const Optional<int64_t>& aEnd,

                const nsAString& aContentType,

                ErrorResult& aRv)

{

  // Truncate aStart and aEnd so that we stay within this file.

  uint64_t thisLength = GetSize(aRv);

  if (NS_WARN_IF(aRv.Failed())) {

    return nullptr;

  }

  int64_t start = aStart.WasPassed() ? aStart.Value() : 0;

  int64_t end = aEnd.WasPassed() ? aEnd.Value() : (int64_t)thisLength;

  ParseSize((int64_t)thisLength, start, end);

  nsAutoString type(aContentType);

  Blob::MakeValidBlobType(type);

  return CreateSlice((uint64_t)start, (uint64_t)(end - start), type, aRv);

}

NS_IMPL_ISUPPORTS(BlobImpl, BlobImpl)

} // namespace dom

} // namespace mozilla