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/*
* Copyright (c) 2025, Ian Moffett.
* Provided under the BSD-3 clause.
*/
#include <sdk/types.h>
#include <sdk/string.h>
#include <sdk/stdarg.h>
static inline void
printc(char *buf, USIZE size, USIZE *off, char c)
{
if (*off < size - 1) {
buf[(*off)++] = c;
}
buf[*off] = 0;
}
static void
printstr(char *buf, USIZE size, USIZE *off, const char *s)
{
while (*off < size - 1 && *s != '\0') {
buf[(*off)++] = *(s)++;
}
buf[*off] = 0;
}
int
snprintf(char *s, USIZE size, const char *fmt, ...)
{
va_list ap;
int ret;
va_start(ap, fmt);
ret = vsnprintf(s, size, fmt, ap);
va_end(ap);
return ret;
}
int
vsnprintf(char *s, USIZE size, const char *fmt, va_list ap)
{
USIZE tmp_len, num_len, off = 0;
USIZE num = 0;
char c, c1, num_buf[256] = {0};
const char *tmp_str;
BYTE pad_width = 0;
while (off < (size - 1)) {
while (*fmt && *fmt != '%') {
printc(s, size, &off, *fmt++);
}
if (*(fmt)++ == '\0' || off == size - 1) {
return off;
}
/*
* Handle a case where we have "%0N". For example:
* "%04d"
*/
if (*fmt == '0') {
++fmt;
while (*fmt >= '0' && *fmt <= '9') {
pad_width = pad_width * 10 + (*fmt - '0');
++fmt;
}
}
c = *fmt++;
switch (c) {
case 'c':
c1 = (char )va_arg(ap, int);
printc(s, size, &off, c1);
break;
case '%':
printc(s, size, &off, c);
break;
case 'd':
num = va_arg(ap, QUAD);
itoa(num, num_buf, 10);
if (pad_width > 0) {
num_len = strlen(num_buf);
for (USIZE i = num_len; i < pad_width; ++i)
printc(s, size, &off, '0');
pad_width = 0;
}
printstr(s, size, &off, num_buf);
break;
case 'p':
num = va_arg(ap, UQUAD);
itoa(num, num_buf, 16);
tmp_len = strlen(num_buf);
/* Add '0x' prefix */
printc(s, size, &off, '0');
printc(s, size, &off, 'x');
/* XXX: Assumes 64-bit */
for (USIZE i = 0; i < 18 - tmp_len; ++i) {
printc(s, size, &off, '0');
}
printstr(s, size, &off, num_buf + 2);
break;
case 'x':
num = va_arg(ap, UQUAD);
itoa(num, num_buf, 16);
tmp_len = strlen(num_buf);
printstr(s, size, &off, num_buf + 2);
break;
case 's':
tmp_str = va_arg(ap, const char *);
printstr(s, size, &off, tmp_str);
break;
}
}
return 0;
}
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