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/*
* Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Hyra nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/types.h>
#include <stdint.h>
#include <stdio.h>
static inline void
printc(char *buf, size_t size, size_t *off, char c)
{
if (*off < size - 1) {
buf[(*off)++] = c;
}
buf[*off] = 0;
}
static void
printstr(char *buf, size_t size, size_t *off, const char *s)
{
while (*off < size - 1 && *s != '\0') {
buf[(*off)++] = *(s)++;
}
buf[*off] = 0;
}
static void
dec_to_str(int value, char *buf, size_t size, size_t *off)
{
size_t i = 0;
uint8_t is_negative = 0;
uint8_t tmp;
char intbuf[4096];
if (value == 0) {
intbuf[i++] = '0';
intbuf[i++] = '\0';
printstr(buf, size, off, intbuf);
return;
}
if (value < 0) {
/* Easier to handle positive numbers */
value *= -1;
is_negative = 1;
}
while (value > 0) {
intbuf[i++] = '0' + (value % 10);
value /= 10;
}
if (is_negative) {
intbuf[i++] = '-';
}
intbuf[i--] = '\0';
/* Result is in reverse */
for (int j = 0; j < i; ++j, --i) {
tmp = intbuf[j];
intbuf[j] = intbuf[i];
intbuf[i] = tmp;
}
printstr(buf, size, off, intbuf);
}
int
vsnprintf(char *s, size_t size, const char *fmt, va_list ap)
{
size_t tmp_len, off = 0;
ssize_t num = 0;
char c, c1;
const char *tmp_str;
int tmp_num;
while (off < (size - 1)) {
while (*fmt && *fmt != '%') {
printc(s, size, &off, *fmt++);
}
if (*(fmt)++ == '\0' || off == size - 1) {
return off;
}
c = *fmt++;
switch (c) {
case 'c':
c1 = (char)va_arg(ap, int);
printc(s, size, &off, c1);
break;
case 's':
tmp_str = va_arg(ap, const char *);
printstr(s, size, &off, tmp_str);
break;
case 'd':
tmp_num = va_arg(ap, int);
dec_to_str(tmp_num, s, size, &off);
break;
}
}
return 0;
}
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