getdelim.c

/*****************************************************************************
 * getdelim.c: POSIX getdelim() and getline() replacements
 *****************************************************************************
 * Copyright © 2010 Rémi Denis-Courmont
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser 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.
 *****************************************************************************/

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include <stdio.h>
#include <stdlib.h>

ssize_t getdelim (char **restrict lineptr, size_t *restrict n,
                  int delimiter, FILE *restrict stream)
{
    char *ptr = *lineptr;
    size_t size = (ptr != NULL) ? *n : 0;
    size_t len = 0;

    for (;;)
    {
        if ((size - len) <= 2)
        {
            size = size ? (size * 2) : 256;
            ptr = realloc (*lineptr, size);
            if (ptr == NULL)
                return -1;
            *lineptr = ptr;
            *n = size;
        }

        int c = fgetc (stream);
        if (c == -1)
        {
            if (len == 0 || ferror (stream))
                return -1;
            break; /* EOF */
        }
        ptr[len++] = c;
        if (c == delimiter)
            break;
    }

    ptr[len] = '\0';
    return len;
}

ssize_t getline (char **restrict lineptr, size_t *restrict n,
                 FILE *restrict stream)
{
    return getdelim (lineptr, n, '\n', stream);
}