notmuch/compat/getdelim.c

/* getdelim.c --- Implementation of replacement getdelim function.
 * Copyright (C) 1994, 1996, 1997, 1998, 2001, 2003, 2005, 2006, 2007,
 * 2008, 2009 Free Software Foundation, Inc.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 3, or (at
 * your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.  */

/* Ported from glibc by Simon Josefsson. */

#include "compat.h"

#include <stdio.h>

#include <limits.h>
#include <stdint.h>
#include <stdlib.h>
#include <errno.h>

#ifndef SSIZE_MAX
# define SSIZE_MAX ((ssize_t) (SIZE_MAX / 2))
#endif

#if USE_UNLOCKED_IO
# include "unlocked-io.h"
# define getc_maybe_unlocked(fp)        getc (fp)
#elif ! HAVE_FLOCKFILE || ! HAVE_FUNLOCKFILE || ! HAVE_DECL_GETC_UNLOCKED
# undef flockfile
# undef funlockfile
# define flockfile(x) ((void) 0)
# define funlockfile(x) ((void) 0)
# define getc_maybe_unlocked(fp)        getc (fp)
#else
# define getc_maybe_unlocked(fp)        getc_unlocked (fp)
#endif

/* Read up to (and including) a DELIMITER from FP into *LINEPTR (and
 * NUL-terminate it).  *LINEPTR is a pointer returned from malloc (or
 * NULL), pointing to *N characters of space.  It is realloc'ed as
 * necessary.  Returns the number of characters read (not including
 * the null terminator), or -1 on error or EOF.  */

ssize_t
getdelim (char **lineptr, size_t *n, int delimiter, FILE *fp)
{
    ssize_t result = -1;
    size_t cur_len = 0;

    if (lineptr == NULL || n == NULL || fp == NULL) {
	errno = EINVAL;
	return -1;
    }

    flockfile (fp);

    if (*lineptr == NULL || *n == 0) {
	char *new_lineptr;
	*n = 120;
	new_lineptr = (char *) realloc (*lineptr, *n);
	if (new_lineptr == NULL) {
	    result = -1;
	    goto unlock_return;
	}
	*lineptr = new_lineptr;
    }

    for (;;) {
	int i;

	i = getc_maybe_unlocked (fp);
	if (i == EOF) {
	    result = -1;
	    break;
	}

	/* Make enough space for len+1 (for final NUL) bytes.  */
	if (cur_len + 1 >= *n) {
	    size_t needed_max =
		SSIZE_MAX < SIZE_MAX ? (size_t) SSIZE_MAX + 1 : SIZE_MAX;
	    size_t needed = 2 * *n + 1; /* Be generous. */
	    char *new_lineptr;

	    if (needed_max < needed)
		needed = needed_max;
	    if (cur_len + 1 >= needed) {
		result = -1;
		errno = EOVERFLOW;
		goto unlock_return;
	    }

	    new_lineptr = (char *) realloc (*lineptr, needed);
	    if (new_lineptr == NULL) {
		result = -1;
		goto unlock_return;
	    }

	    *lineptr = new_lineptr;
	    *n = needed;
	}

	(*lineptr)[cur_len] = i;
	cur_len++;

	if (i == delimiter)
	    break;
    }
    (*lineptr)[cur_len] = '\0';
    result = cur_len ? (ssize_t) cur_len : result;

  unlock_return:
    funlockfile (fp); /* doesn't set errno */

    return result;
}