reading integer from network stream

Makefile

all: StreamReader.hpp test.cpp
	g++ -o test test.cpp

StreamReader.hpp

#include <endian.h>
#include <string.h>

#include <iostream>


namespace {

template <typename T>
union TypeCaster
{
  T data;
  char bytes[sizeof(T)];
};


template <typename T, int>
struct ByteOrder_ {
  static inline T convert(T val);
};

template<typename T>
struct ByteOrder_<T, 2> {
  static inline T convert(T val) {
    return htobe16(val);
  }
};

template<typename T>
struct ByteOrder_<T, 4> {
  static inline T convert(T val) {
    return htobe32(val);
  }
};


template<typename T>
struct ByteOrder_<T, 8> {
  static inline T convert(T val) {
    return htobe64(val);
  }
};

template<typename T>
struct ByteOrder {
  static inline T convert(T val) {
    return ByteOrder_<T, sizeof(T)>::convert(val);
  }
};

} // namespace

template<typename T>
struct StreamReader
{
  inline static T read(std::istream &in) {
    int size = sizeof(T);

    TypeCaster<T> caster;
    in.read(caster.bytes, size);

    return ByteOrder<T>::convert(caster.data);
  }
};

test.cpp

#include <assert.h>
#include <stdint.h>

#include <iostream>
#include <sstream>
#include <string>

#include "StreamReader.hpp"

int main(void) {
  std::istringstream is("12345678");

  assert (StreamReader<int32_t>::read(is) == 0x31323334);
  assert (StreamReader<int32_t>::read(is) == 0x35363738);

  is.seekg(0, std::ios::beg);

  assert (StreamReader<int64_t>::read(is) == 0x3132333435363738);

  is.seekg(3, std::ios::beg);
  assert (StreamReader<int16_t>::read(is) == 0x3435);
  
  return 0;
}