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#include <printf.h>
#include <stdarg.h>
int snprintf(char * buff, size_t len, const char *format, ...) {
va_list ap;
va_start(ap, format);
len = vsnprintf(buff, len, format, ap);
va_end(ap);
return len;
}
int vsnprintf(char *buff, size_t len, const char* format, va_list ap){
size_t i, result;
if (!buff || !format)
return -1;
#define PUTCHAR(thechar) \
do { \
if (result < len-1) \
*buff++ = (thechar); \
result++; \
} while (0)
result = 0;
for(i = 0; format[i] != '\0' ; i++) {
if (format[i] == '%') {
i++;
switch(format[i]) {
case '%':
PUTCHAR('%');
break;
case 'i':;
case 'd': {
int integer = va_arg(ap,int);
int cpt2 = 0;
char buff_int[16];
if (integer<0)
PUTCHAR('-');
do {
int m10 = integer%10;
m10 = (m10 < 0)? -m10:m10;
buff_int[cpt2++] = (char)('0'+ m10);
integer = integer/10;
} while(integer != 0);
for(cpt2 = cpt2 - 1; cpt2 >= 0; cpt2--)
PUTCHAR(buff_int[cpt2]);
break;
}
case 'c': {
int value = va_arg(ap,int);
PUTCHAR((char)value);
break;
}
case 's': {
char *string = va_arg(ap,char *);
if (!string)
string = "(null)";
for(; *string != '\0' ; string++)
PUTCHAR(*string);
break;
}
case 'x': {
unsigned int hexa = va_arg(ap,int);
unsigned int nb;
int j, had_nonzero = 0;
for(j = 0; j < 8; j++)
{
nb = (unsigned int)(hexa << (j*4));
nb = (nb >> 28) & 0xf;
// Skip the leading zeros
if (nb == 0) {
if (had_nonzero)
PUTCHAR('0');
} else {
had_nonzero = 1;
if (nb < 10)
PUTCHAR('0'+nb);
else
PUTCHAR('a'+(nb-10));
}
}
if (!had_nonzero)
PUTCHAR('0');
break;
}
default:
PUTCHAR('%');
PUTCHAR(format[i]);
}
} else {
PUTCHAR(format[i]);
}
}
*buff = '\0';
return result;
}
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