BufferReader.h

#ifndef PACKING_BUFFER_H_
#define PACKING_BUFFER_H_
 
#include <cstdint>
#include <stdexcept>
#include <vector>
 
namespace packing {
namespace utility {
 
template <typename WordType>
class BufferReader {
 public:
  BufferReader(const std::vector<uint8_t>& b) : buffer_{b}, i_word_{0} {}
 
  operator bool() { return (i_word_ < buffer_.size()); }
 
  BufferReader& operator>>(WordType& w) {
    if (*this) w = next();
    return *this;
  }
 
 private:
  WordType next() {
    WordType w{0};
    for (std::size_t i_byte{0}; i_byte < N_BYTES; i_byte++) {
      w |= (buffer_.at(i_word_ + i_byte) << 8 * i_byte);
    }
    i_word_ += N_BYTES;
    return w;
  }
 
 private:
  // number of bytes in the words we are reading
  static const std::size_t N_BYTES{sizeof(WordType)};
  // current buffer we are reading
  const std::vector<uint8_t>& buffer_;
  // current index in buffer we are reading
  std::size_t i_word_;
};  // BufferReader
 
}  // namespace utility
}  // namespace packing
 
#endif  // PACKING_BUFFERREADER_H_