src/stdio/getdelim.c

   1 #include "stdio_impl.h"
   2 #include <string.h>
   3 #include <stdlib.h>
   4 #include <inttypes.h>
   5 #include <errno.h>
   6
   7 ssize_t getdelim(char **restrict s, size_t *restrict n, int delim, FILE *restrict f)
   8 {
   9         char *tmp;
  10         unsigned char *z;
  11         size_t k;
  12         size_t i=0;
  13         int c;
  14
  15         FLOCK(f);
  16
  17         if (!n || !s) {
  18                 f->mode |= f->mode-1;
  19                 f->flags |= F_ERR;
  20                 FUNLOCK(f);
  21                 errno = EINVAL;
  22                 return -1;
  23         }
  24
  25         if (!*s) *n=0;
  26
  27         for (;;) {
  28                 if (f->rpos != f->rend) {
  29                         z = memchr(f->rpos, delim, f->rend - f->rpos);
  30                         k = z ? z - f->rpos + 1 : f->rend - f->rpos;
  31                 } else {
  32                         z = 0;
  33                         k = 0;
  34                 }
  35                 if (i+k >= *n) {
  36                         size_t m = i+k+2;
  37                         if (!z && m < SIZE_MAX/4) m += m/2;
  38                         tmp = realloc(*s, m);
  39                         if (!tmp) {
  40                                 m = i+k+2;
  41                                 tmp = realloc(*s, m);
  42                                 if (!tmp) {
  43                                         /* Copy as much as fits and ensure no
  44                                          * pushback remains in the FILE buf. */
  45                                         k = *n-i;
  46                                         memcpy(*s+i, f->rpos, k);
  47                                         f->rpos += k;
  48                                         f->mode |= f->mode-1;
  49                                         f->flags |= F_ERR;
  50                                         FUNLOCK(f);
  51                                         errno = ENOMEM;
  52                                         return -1;
  53                                 }
  54                         }
  55                         *s = tmp;
  56                         *n = m;
  57                 }
  58                 memcpy(*s+i, f->rpos, k);
  59                 f->rpos += k;
  60                 i += k;
  61                 if (z) break;
  62                 if ((c = getc_unlocked(f)) == EOF) {
  63                         if (!i || !feof(f)) {
  64                                 FUNLOCK(f);
  65                                 return -1;
  66                         }
  67                         break;
  68                 }
  69                 /* If the byte read by getc won't fit without growing the
  70                  * output buffer, push it back for next iteration. */
  71                 if (i+1 >= *n) *--f->rpos = c;
  72                 else if (((*s)[i++] = c) == delim) break;
  73         }
  74         (*s)[i] = 0;
  75
  76         FUNLOCK(f);
  77
  78         return i;
  79 }
  80
  81 weak_alias(getdelim, __getdelim);