utils.c

/*
 * Copyright (c) 2016-2018 . All Rights Reserved.
 */

#include "utils.h"

int size_of_bytes(int str_len) {
    int out_len = (str_len & 1) ? (str_len + 1) / 2 : str_len / 2;
    return out_len;
}

uint8_t strtohex(char c) {
    if (c >= '0' && c <= '9')
        return c - '0';
    if (c >= 'a' && c <= 'f')
        return c - 'a' + 10;
    if (c >= 'A' && c <= 'F')
        return c - 'A' + 10;
    return 255;
}

int hex2byte_arr(char *buf, int len, uint8_t *out, int outbuf_size) {
    int i = len - 1;
    int out_len = (len & 1) ? (len + 1) / 2 : len / 2;
    int j = out_len - 1;

    if (j > outbuf_size)
        return -1; /* Output buffer is smaller than need */

    while (i >= 0) {
        out[j] = strtohex(buf[i--]);
        if (i >= 0) {
            out[j--] |= strtohex(buf[i--]) << 4;
        }
    }

    return out_len;
}

void int8_to_char(uint8_t *buffer, int len, char *out) {
    const char hex[] = "0123456789abcdef";
    int max = 2 * len;
    int i = 0;
    int j = 0;
    while (j < len) {
        out[i++] = hex[(buffer[j] >> 4) & 0xF];
        out[i++] = hex[buffer[j] & 0xF];
        j++;
    }
    out[i] = '\0';
}