/*
 * Copyright © 2024 Nick Bowler
 *
 * getline-like function which removes trailing newline (if any), and
 * returns nonzero if and only if a line was successfully read.
 *
 * 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 <https://www.gnu.org/licenses/>.
 */

#include <stdio.h>
#include <string.h>
#include <limits.h>
#include <errno.h>

#ifdef CDECL_TEST_H_
/*
 * Use the minimum initial alloc size in the test programs to ensure we at
 * least are exercising the realloc path on a reasonably regular basis.
 */
#  define CDECL99_GETLINE_INITIAL_ALLOC 1
#else
#  define CDECL99_GETLINE_INITIAL_ALLOC 75
#endif

static inline int do_getline(char **linebuf, size_t *n)
{
	extern void print_error(const char *fmt, ...);
	const char *errmsg;

#if HAVE_GETLINE
	ssize_t rc;

	if ((rc = getline(linebuf, n, stdin)) < 0) {
		if (ferror(stdin))
			goto input_error;
		return 0;
	}

	if (rc-- && (*linebuf)[rc] == '\n')
		(*linebuf)[rc] = '\0';
	return 1;
#else
	char *work = *linebuf;
	size_t pos = 0;
	size_t sz;

	if (!work) {
		sz = CDECL99_GETLINE_INITIAL_ALLOC;
		goto initial_alloc;
	}

	for (sz = *n;;) {
		if (!fgets(&work[pos], sz - pos, stdin)) {
			if (ferror(stdin))
				goto input_error;

			return !!pos;
		}

		pos += strlen(&work[pos]);
		if (work[pos-1] == '\n') {
			work[pos-1] = '\0';
			return 1;
		}

		if (sz > INT_MAX/2 || sz > ((size_t)-1)/4)
			break;

		sz = ((sz*4) + 2) / 3;
initial_alloc:
		work = realloc(work, sz);
		if (!work)
			break;
		*linebuf = work;
		*n = sz;
	}

	errmsg = _("failed to allocate memory");
#endif
	if (0) input_error: errmsg = strerror(errno);
	print_error("%s", errmsg);
	return 0;
}