simplify vasprintf implementation

the old implementation preallocated a buffer in order to try to avoid
calling vsnprintf more than once. not only did this potentially lead
to memory fragmentation from trimming with realloc; it also pulled in
realloc/free, which otherwise might not be needed in a static linked
program.
This commit is contained in:
Rich Felker 2014-06-04 03:39:22 -04:00
parent bdad2fefb2
commit 6a25313c11

View File

@ -3,26 +3,13 @@
#include <stdarg.h>
#include <stdlib.h>
#define GUESS 240U
int vasprintf(char **s, const char *fmt, va_list ap)
{
va_list ap2;
char *a;
int l=GUESS;
if (!(a=malloc(GUESS))) return -1;
va_copy(ap2, ap);
l=vsnprintf(a, GUESS, fmt, ap2);
int l = vsnprintf(0, 0, fmt, ap2);
va_end(ap2);
if (l<GUESS) {
char *b = realloc(a, l+1U);
*s = b ? b : a;
return l;
}
free(a);
if (l<0 || !(*s=malloc(l+1U))) return -1;
return vsnprintf(*s, l+1U, fmt, ap);
}