1 files changed, 108 insertions, 0 deletions
diff --git a/lib/linelength.c b/lib/linelength.c
new file mode 100644
index 0000000..69a702f
--- /dev/null
+++ b/lib/linelength.c
@@ -0,0 +1,108 @@
+/*
+ * linelength.c: find the terminal line length
+ * Preferences: 1. MANWIDTH, 2. COLUMNS, 3. ioctl, 4. 80
+ *
+ * Originally adapted from Andries Brouwer's man implementation, also
+ * released under the GPL: authors believed to include Martin Schulze and
+ * Jon Tombs, dated 1995/09/02.
+ *
+ * Changes for man-db copyright (C) 2001, 2003, 2007 Colin Watson.
+ *
+ * This file is part of man-db.
+ *
+ * man-db 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 2 of the License, or
+ * (at your option) any later version.
+ *
+ * man-db 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 man-db; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#  include "config.h"
+#endif /* HAVE_CONFIG_H */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <termios.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+#ifndef _PATH_TTY
+# define _PATH_TTY "/dev/tty"
+#endif /* _PATH_TTY */
+
+static int line_length = -1;
+
+int get_line_length (void)
+{
+	const char *columns;
+	int width;
+#ifdef TIOCGWINSZ
+	int dev_tty, tty_fd = -1;
+#endif
+
+	if (line_length != -1)
+		return line_length;
+
+	line_length = 80;
+
+	columns = getenv ("MANWIDTH");
+	if (columns != NULL) {
+		width = atoi (columns);
+		if (width > 0)
+			return line_length = width;
+	}
+
+	columns = getenv ("COLUMNS");
+	if (columns != NULL) {
+		width = atoi (columns);
+		if (width > 0)
+			return line_length = width;
+	}
+
+#ifdef TIOCGWINSZ
+	/* Original TIOCGWINSZ approach was from Jon Tombs.
+	 * We don't require both stdin and stdout to be a tty, and line
+	 * length is primarily a property of output. However, if it happens
+	 * that stdin is connected to a terminal but stdout isn't, then that
+	 * may well be because the user is trying something like
+	 * 'MAN_KEEP_STDERR=1 man foo >/dev/null' to see just the error
+	 * messages, so use the window size from stdin as a fallback.
+	 * In some cases we may have neither (e.g. if man is running inside
+	 * lesspipe); /dev/tty should be a reliable way to get to the
+	 * current tty if it exists.
+	 */
+	dev_tty = open (_PATH_TTY, O_RDONLY);
+	if (dev_tty >= 0)
+		tty_fd = dev_tty;
+	else if (isatty (STDOUT_FILENO))
+		tty_fd = STDOUT_FILENO;
+	else if (isatty (STDIN_FILENO))
+		tty_fd = STDIN_FILENO;
+	if (tty_fd >= 0) {
+		int ret;
+		struct winsize wsz;
+
+		ret = ioctl (tty_fd, TIOCGWINSZ, &wsz);
+		if (dev_tty >= 0)
+			close (dev_tty);
+		if (ret)
+			perror ("TIOCGWINSZ failed");
+		else if (wsz.ws_col)
+			return line_length = wsz.ws_col;
+	}
+#endif
+
+	return line_length = 80;
+}