//

//  readstat_bits.c - Bit-twiddling utility functions

//

#include <sys/types.h>

#include <stdint.h>

#include <string.h>

#include "readstat_bits.h"

int machine_is_little_endian(void) {

    int test_byte_order = 1;

    return ((char *)&test_byte_order)[0];

}

char ones_to_twos_complement1(char num) {

    return num < 0 ? num+1 : num;

}

int16_t ones_to_twos_complement2(int16_t num) {

    return num < 0 ? num+1 : num;

}

int32_t ones_to_twos_complement4(int32_t num) {

    return num < 0 ? num+1 : num;

}

char twos_to_ones_complement1(char num) {

    return num < 0 ? num-1 : num;

}

int16_t twos_to_ones_complement2(int16_t num) {

    return num < 0 ? num-1 : num;

}

int32_t twos_to_ones_complement4(int32_t num) {

    return num < 0 ? num-1 : num;

}

uint16_t byteswap2(uint16_t num) {

    return ((num & 0xFF00) >> 8) | ((num & 0x00FF) << 8);

}

uint32_t byteswap4(uint32_t num) {

    num = ((num & 0xFFFF0000) >> 16) | ((num & 0x0000FFFF) << 16);

    return ((num & 0xFF00FF00) >> 8) | ((num & 0x00FF00FF) << 8);

}

uint64_t byteswap8(uint64_t num) {

    num = ((num & 0xFFFFFFFF00000000) >> 32) | ((num & 0x00000000FFFFFFFF) << 32);

    num = ((num & 0xFFFF0000FFFF0000) >> 16) | ((num & 0x0000FFFF0000FFFF) << 16);

    return ((num & 0xFF00FF00FF00FF00) >> 8) | ((num & 0x00FF00FF00FF00FF) << 8);

}

float byteswap_float(float num) {

    uint32_t answer = 0;

    memcpy(&answer, &num, 4);

    answer = byteswap4(answer);

    memcpy(&num, &answer, 4);

    return num;

}

double byteswap_double(double num) {

    uint64_t answer = 0;

    memcpy(&answer, &num, 8);

    answer = byteswap8(answer);

    memcpy(&num, &answer, 8);

    return num;

}