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// See LICENSE for license details.
#include <stdint.h>
#include <string.h>
#include <stdarg.h>
#include <stdbool.h>
int vsnprintf(char* out, size_t n, const char* s, va_list vl)
{
bool format = false;
bool longarg = false;
bool longlongarg = false;
size_t pos = 0;
for( ; *s; s++)
{
if(format)
{
switch(*s)
{
case 'l':
if (s[1] == 'l') {
longlongarg = true;
s++;
}
else
longarg = true;
break;
case 'p':
longarg = true;
if (++pos < n) out[pos-1] = '0';
if (++pos < n) out[pos-1] = 'x';
case 'x':
{
long num = longarg ? va_arg(vl, long) : va_arg(vl, int);
for(int i = 2*(longarg ? sizeof(long) : sizeof(int))-1; i >= 0; i--) {
int d = (num >> (4*i)) & 0xF;
if (++pos < n) out[pos-1] = (d < 10 ? '0'+d : 'a'+d-10);
}
longarg = false;
format = false;
break;
}
case 'd':
{
long long num;
if (longarg)
num = va_arg(vl, long);
else if (longlongarg)
num = va_arg(vl, long long);
else
num = va_arg(vl, int);
if (num < 0) {
num = -num;
if (++pos < n) out[pos-1] = '-';
}
long digits = 1;
for (long long nn = num; nn /= 10; digits++)
;
for (int i = digits-1; i >= 0; i--) {
if (pos + i + 1 < n) out[pos + i] = '0' + (num % 10);
num /= 10;
}
pos += digits;
longarg = false;
longlongarg = false;
format = false;
break;
}
case 's':
{
const char* s2 = va_arg(vl, const char*);
while (*s2) {
if (++pos < n)
out[pos-1] = *s2;
s2++;
}
longarg = false;
format = false;
break;
}
case 'c':
{
if (++pos < n) out[pos-1] = (char)va_arg(vl,int);
longarg = false;
format = false;
break;
}
default:
break;
}
}
else if(*s == '%')
format = true;
else
if (++pos < n) out[pos-1] = *s;
}
if (pos < n)
out[pos] = 0;
else if (n)
out[n-1] = 0;
return pos;
}
int snprintf(char* out, size_t n, const char* s, ...)
{
va_list vl;
va_start(vl, s);
int res = vsnprintf(out, n, s, vl);
va_end(vl);
return res;
}
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