+/*
+ * 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;
+}
+