// Copyright 2008, Google Inc.
//
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// modification, are permitted provided that the following conditions are met:
//
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//     this list of conditions and the following disclaimer.
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//     used to endorse or promote products derived from this software without
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#ifdef OFFICIAL_BUILD
// The blob API has not been finalized for official builds
#else

#include <algorithm>
#include <cassert>
#include <limits>
#include "gears/blob/buffer_blob.h"

BufferBlob::BufferBlob(std::vector<uint8> *buffer) {
  buffer_.swap(*buffer);
}

BufferBlob::BufferBlob(const void *source, int64 num_bytes)
    : buffer_(static_cast<const uint8*>(source),
              static_cast<const uint8*>(source) + num_bytes) {
  // The current implementation of BufferBlob stores data in a vector.
  // A vector has an upper bound for how much data it can hold.
  // Make sure we haven't gone beyond this limit.
  assert(num_bytes <= buffer_.max_size());
}

int64 BufferBlob::Read(uint8 *destination, int64 offset,
                       int64 max_bytes) const {
  if (offset < 0 || max_bytes < 0) {
    return -1;
  }
  if (offset >= buffer_.size() || max_bytes == 0) {
    return 0;
  }
  int64 available = buffer_.size() - offset;
  int64 num_bytes = std::min(available, max_bytes);
  if (num_bytes > std::numeric_limits<size_t>::max()) {
    num_bytes = static_cast<int64>(std::numeric_limits<size_t>::max());
  }
  memcpy(destination, &(buffer_[static_cast<size_type>(offset)]),
         static_cast<size_t>(num_bytes));
  return num_bytes;
}

int64 BufferBlob::Length() const {
  return buffer_.size();
}

#endif  // not OFFICIAL_BUILD