1 files changed, 24 insertions, 0 deletions
diff --git a/line-range.h b/line-range.h
new file mode 100644
index 0000000000..830f25b501
--- /dev/null
+++ b/line-range.h
@@ -0,0 +1,24 @@
+#ifndef LINE_RANGE_H
+#define LINE_RANGE_H
+
+/*
+ * Parse one item in an -L begin,end option w.r.t. the notional file
+ * object 'cb_data' consisting of 'lines' lines.
+ *
+ * The 'nth_line_cb' callback is used to determine the start of the
+ * line 'lno' inside the 'cb_data'.  The caller is expected to already
+ * have a suitable map at hand to make this a constant-time lookup.
+ *
+ * Returns 0 in case of success and -1 if there was an error.  The
+ * actual range is stored in *begin and *end.  The counting starts
+ * at 1!  In case of error, the caller should show usage message.
+ */
+
+typedef const char *(*nth_line_fn_t)(void *data, long lno);
+
+extern int parse_range_arg(const char *arg,
+			   nth_line_fn_t nth_line_cb,
+			   void *cb_data, long lines,
+			   long *begin, long *end);
+
+#endif /* LINE_RANGE_H */