fusl/src/stdio/getdelim.c

#include "stdio_impl.h"
#include <string.h>
#include <inttypes.h>
#include <errno.h>

#define MIN(a, b) ((a) < (b) ? (a) : (b))

ssize_t getdelim(char** restrict s,
                 size_t* restrict n,
                 int delim,
                 FILE* restrict f) {
  char* tmp;
  unsigned char* z;
  size_t k;
  size_t i = 0;
  int c;

  FLOCK(f);

  if (!n || !s) {
    f->flags |= F_ERR;
    FUNLOCK(f);
    errno = EINVAL;
    return -1;
  }

  if (!*s)
    *n = 0;

  for (;;) {
    z = memchr(f->rpos, delim, f->rend - f->rpos);
    k = z ? z - f->rpos + 1 : f->rend - f->rpos;
    if (i + k + 1 >= *n) {
      if (k >= SIZE_MAX / 2 - i)
        goto oom;
      size_t m = i + k + 2;
      if (!z && m < SIZE_MAX / 4)
        m += m / 2;
      tmp = realloc(*s, m);
      if (!tmp) {
        m = i + k + 2;
        tmp = realloc(*s, m);
        if (!tmp)
          goto oom;
      }
      *s = tmp;
      *n = m;
    }
    memcpy(*s + i, f->rpos, k);
    f->rpos += k;
    i += k;
    if (z)
      break;
    if ((c = getc_unlocked(f)) == EOF) {
      if (!i || !feof(f)) {
        FUNLOCK(f);
        return -1;
      }
      break;
    }
    if (((*s)[i++] = c) == delim)
      break;
  }
  (*s)[i] = 0;

  FUNLOCK(f);

  return i;
oom:
  f->flags |= F_ERR;
  FUNLOCK(f);
  errno = ENOMEM;
  return -1;
}

weak_alias(getdelim, __getdelim);