range-set: publish API for re-use by git-blame -L

git-blame is slated to accept multiple -L ranges.  git-log already
accepts multiple -L's but its implementation of range-set, which
organizes and normalizes -L ranges, is private.  Publish the small
subset of range-set API which is needed for git-blame multiple -L
support.

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

line-log.c

@@ -23,7 +23,7 @@ static void range_set_grow(struct range_set *rs, size_t extra)
 /* Either initialization would be fine */
 #define RANGE_SET_INIT {0}
 
-static void range_set_init(struct range_set *rs, size_t prealloc)
+void range_set_init(struct range_set *rs, size_t prealloc)
 {
 	rs->alloc = rs->nr = 0;
 	rs->ranges = NULL;
@@ -31,7 +31,7 @@ static void range_set_init(struct range_set *rs, size_t prealloc)
 		range_set_grow(rs, prealloc);
 }
 
-static void range_set_release(struct range_set *rs)
+void range_set_release(struct range_set *rs)
 {
 	free(rs->ranges);
 	rs->alloc = rs->nr = 0;
@@ -56,7 +56,7 @@ static void range_set_move(struct range_set *dst, struct range_set *src)
 }
 
 /* tack on a _new_ range _at the end_ */
-static void range_set_append_unsafe(struct range_set *rs, long a, long b)
+void range_set_append_unsafe(struct range_set *rs, long a, long b)
 {
 	assert(a <= b);
 	range_set_grow(rs, 1);
@@ -65,7 +65,7 @@ static void range_set_append_unsafe(struct range_set *rs, long a, long b)
 	rs->nr++;
 }
 
-static void range_set_append(struct range_set *rs, long a, long b)
+void range_set_append(struct range_set *rs, long a, long b)
 {
 	assert(rs->nr == 0 || rs->ranges[rs->nr-1].end <= a);
 	range_set_append_unsafe(rs, a, b);
@@ -107,7 +107,7 @@ static void range_set_check_invariants(struct range_set *rs)
  * In-place pass of sorting and merging the ranges in the range set,
  * to establish the invariants when we get the ranges from the user
  */
-static void sort_and_merge_range_set(struct range_set *rs)
+void sort_and_merge_range_set(struct range_set *rs)
 {
 	int i;
 	int o = 0; /* output cursor */

line-log.h

@@ -25,6 +25,18 @@ struct diff_ranges {
 	struct range_set target;
 };
 
+extern void range_set_init(struct range_set *, size_t prealloc);
+extern void range_set_release(struct range_set *);
+/* Range includes start; excludes end */
+extern void range_set_append_unsafe(struct range_set *, long start, long end);
+/* New range must begin at or after end of last added range */
+extern void range_set_append(struct range_set *, long start, long end);
+/*
+ * In-place pass of sorting and merging the ranges in the range set,
+ * to sort and make the ranges disjoint.
+ */
+extern void sort_and_merge_range_set(struct range_set *);
+
 /* Linked list of interesting files and their associated ranges.  The
  * list must be kept sorted by path.
  *