strutils.c

/*

    arfhttpd: Yet another HTTP server
    Copyright (C) 2023 arf20 (Ángel Ruiz Fernandez)

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <https://www.gnu.org/licenses/>.

    strutils.c: string utilities

*/

#include "strutils.h"

#include <string.h>
#include <stdio.h>

size_t /* from BSD */
strlcat(char *dst, const char *src, size_t dstsize) {
    int d_len, s_len, offset, src_index;

    /* obtain initial sizes */
    d_len = strlen(dst);
    s_len = strlen(src);

    /* get the end of dst */
    offset = d_len;

    /* append src */
    src_index = 0;
    while(*(src+src_index) != '\0')
    {
        *(dst + offset) = *(src + src_index);
        offset++;
        src_index++;
        /* don't copy more than dstsize characters
           minus one */
        if(offset == dstsize - 1)
            break;
    }
    /* always cap the string! */
    *(dst + offset) = '\0';

    return d_len + s_len;
}

void
strsub(char *dest, size_t destsize, const char *src, size_t n) {
    int i = 0;
    for (i = 0; i < n && i < destsize && src[i]; i++)
        dest[i] = src[i];
    dest[i] = '\0';
}

char *
stralloccpy(const char *start, size_t length) {
    if (!start) return NULL;
    char *str = malloc(length + 1);
    strncpy(str, start, length);
    str[length] = '\0';
    return str;
}

char *
human_size(int isize, char *buf, size_t buflen) {
    int i = 0;
    float size = isize;
    const char *units[] = {"B", "KiB", "MiB", "GiB", "TiB"};
    while (size > 1024.0f) {
        size /= 1024.0f;
        i++;
    }
    snprintf(buf, buflen, "%.*f %s", i, size, units[i]);
    return buf;
}

const char *
strnchr(const char *str, size_t n, char chr) {
    for (int i = 0; i < n; i++)
        if (str[i] == chr) return str + i;
    return NULL;
}