/* zlib-extra.c -  Extra or enhanced routines for compressed I/O.
 *
 * Copyright (c) 2014 David Bremner
 *
 * 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 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see http://www.gnu.org/licenses/ .
 *
 * Author: David Bremner <david@tethera.net>
 */

#include "zlib-extra.h"
#include <talloc.h>
#include <stdio.h>
#include <string.h>

/* mimic POSIX/glibc getline, but on a zlib gzFile stream, and using talloc */
ssize_t
gzgetline (void *ctx, char **lineptr, size_t *n, gzFile stream) {

    size_t len = *n;
    char *buf = *lineptr;
    size_t offset = 0;

    if (len == 0 || buf == NULL) {
	/* same as getdelim from gnulib */
	len = 120;
	buf = talloc_size (ctx, len);
	if (buf == NULL)
	    return -1;
    }

    while (1) {

	if (!gzgets (stream, buf + offset, len - offset))
	    return -1;

	offset += strlen (buf+offset);

	if ( buf[offset-1] == '\n' )
	    break;

	len *= 2;
	buf = talloc_realloc (ctx, buf, char, len);
	if (buf == NULL)
	    return -1;

    }

    *lineptr = buf;
    *n = len;
    return offset;
}