Endianness conversions with positive integers

endianness.c

// converts 32-bits positive integer to 4-bytes little endian
void to4li(unsigned long int const value, char * const buffer)
{
	buffer[0] = value >> 8 * 0;
	buffer[1] = value >> 8 * 1;
	buffer[2] = value >> 8 * 2;
	buffer[3] = value >> 8 * 3;
}

// converts 16-bits positive integer to 2-bytes little endian
void to2li(unsigned short const value, char * const buffer)
{
	buffer[0] = value >> 8 * 0;
	buffer[1] = value >> 8 * 1;
}

// converts 32-bits positive integer to 4-bytes big endian
void to4bi(unsigned long int const value, char * const buffer)
{
	buffer[0] = value >> 8 * 3;
	buffer[1] = value >> 8 * 2;
	buffer[2] = value >> 8 * 1;
	buffer[3] = value >> 8 * 0;
}

// converts 16-bits positive integer to 2-bytes big endian
void to2bi(unsigned short const value, char * const buffer)
{
	buffer[0] = value >> 8 * 1;
	buffer[1] = value >> 8 * 0;
}

// converts 4-bytes little endian to 32-bits positive integer
unsigned long int from4li(char const * const buffer)
{
	unsigned long int value = 0;
	
	value += (unsigned char) buffer[0] << 8 * 0;
	value += (unsigned char) buffer[1] << 8 * 1;
	value += (unsigned char) buffer[2] << 8 * 2;
	value += (unsigned char) buffer[3] << 8 * 3;
	
	return value;
}

// converts 2-bytes little endian to 16-bits positive integer
unsigned short int from2li(char const * const buffer)
{
	unsigned short int value = 0;
	
	value += (unsigned char) buffer[0] << 8 * 0;
	value += (unsigned char) buffer[1] << 8 * 1;
	
	return value;
}

// converts 4-bytes big endian to 32-bits positive integer
unsigned long int from4bi(char const * const buffer)
{
	unsigned long int value = 0;
	
	value += (unsigned char) buffer[0] << 8 * 3;
	value += (unsigned char) buffer[1] << 8 * 2;
	value += (unsigned char) buffer[2] << 8 * 1;
	value += (unsigned char) buffer[3] << 8 * 0;
	
	return value;
}

// converts 2-bytes big endian to 16-bits positive integer
unsigned short int from2bi(char const * const buffer)
{
	unsigned short int value = 0;
	
	value += (unsigned char) buffer[0] << 8 * 1;
	value += (unsigned char) buffer[1] << 8 * 0;
	
	return value;
}