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riscv-pke/util/snprintf.c

84 lines
2.0 KiB

/*
* vsnprintf() is borrowed from pk.
*/
//#include <stdint.h>
//#include <stdarg.h>
//#include <stdbool.h>
#include "util/snprintf.h"
int32 vsnprintf(char* out, size_t n, const char* s, va_list vl) {
bool format = FALSE;
bool longarg = FALSE;
size_t pos = 0;
for (; *s; s++) {
if (format) {
switch (*s) {
case 'l':
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 num = longarg ? va_arg(vl, long) : va_arg(vl, int);
if (num < 0) {
num = -num;
if (++pos < n) out[pos - 1] = '-';
}
long digits = 1;
for (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;
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;
}