1 files changed, 71 insertions, 0 deletions
diff --git a/src/util/line_number.c b/src/util/line_number.c
new file mode 100644
index 0000000..557e053
--- /dev/null
+++ b/src/util/line_number.c
@@ -0,0 +1,71 @@
+/*++
+/* NAME
+/*	line_number 3
+/* SUMMARY
+/*	line number utilities
+/* SYNOPSIS
+/*	#include <line_number.h>
+/*
+/*	char	*format_line_number(result, first, last)
+/*	VSTRING	*buffer;
+/*	ssize_t	first;
+/*	ssize_t	lastl
+/* DESCRIPTION
+/*	format_line_number() formats a line number or number range.
+/*	The output is <first-number>-<last-number> when the numbers
+/*	differ, <first-number> when the numbers are identical.
+/* .IP result
+/*	Result buffer, or null-pointer. In the latter case the
+/*	result is stored in a static buffer that is overwritten
+/*	with subsequent calls. The function result value is a
+/*	pointer into the result buffer.
+/* .IP first
+/*	First line number.
+/* .IP last
+/*	Last line number.
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*--*/
+
+ /*
+  * System library.
+  */
+#include <sys_defs.h>
+
+ /*
+  * Utility library.
+  */
+#include <vstring.h>
+#include <line_number.h>
+
+/* format_line_number - pretty-print line number or number range */
+
+char   *format_line_number(VSTRING *result, ssize_t first, ssize_t last)
+{
+    static VSTRING *buf;
+
+    /*
+     * Your buffer or mine?
+     */
+    if (result == 0) {
+	if (buf == 0)
+	    buf = vstring_alloc(10);
+	result = buf;
+    }
+
+    /*
+     * Print a range only when the numbers differ.
+     */
+    vstring_sprintf(result, "%ld", (long) first);
+    if (first != last)
+	vstring_sprintf_append(result, "-%ld", (long) last);
+
+    return (vstring_str(result));
+}