com32/lib/bufprintf.c

   1 #include <stdarg.h>
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <bufprintf.h>
   5
   6 int vbufprintf(struct print_buf *buf, const char *format, va_list ap)
   7 {
   8     va_list ap2;
   9     int rv;
  10
  11     va_copy(ap2, ap);
  12     rv = vsnprintf(NULL, 0, format, ap);
  13
  14     /* >= to make sure we have space for terminating null */
  15     if (rv + buf->len >= buf->size) {
  16         size_t newsize = rv + buf->len + BUFPAD;
  17         char *newbuf;
  18
  19         newbuf = realloc(buf->buf, newsize);
  20         if (!newbuf) {
  21             rv = -1;
  22             goto bail;
  23         }
  24
  25         buf->buf = newbuf;
  26         buf->size = newsize;
  27     }
  28
  29     rv = vsnprintf(buf->buf + buf->len, buf->size - buf->len, format, ap2);
  30     buf->len += rv;
  31 bail:
  32     va_end(ap2);
  33     return rv;
  34 }
  35
  36 int bufprintf(struct print_buf *buf, const char *format, ...)
  37 {
  38     va_list ap;
  39     int rv;
  40
  41     va_start(ap, format);
  42     rv = vbufprintf(buf, format, ap);
  43     va_end(ap);
  44     return rv;
  45 }