[WIP PATCH 07/22] Add range clone functions

[Bo Yang <struggleyb.nku@gmail.com>]

Since diff_line_range can form a single list through its
'next' pointer, we provide two kind of clone.

diff_line_range_clone:
	used to clone only the element node and set the
	element's 'next' pointer to NULL.
diff_line_range_clone_deeply:
	used to clone the whole list of ranges.

Signed-off-by: Bo Yang <struggleyb.nku@gmail.com>
---
 line.c |   39 +++++++++++++++++++++++++++++++++++++++
 line.h |    4 ++++
 2 files changed, 43 insertions(+), 0 deletions(-)

diff --git a/line.c b/line.c
index 4314cee..c9ff934 100644
--- a/line.c
+++ b/line.c
@@ -382,6 +382,45 @@ void diff_line_range_append(struct diff_line_range *r, const char *arg)
 	r->ranges[r->nr - 1].arg = arg;
 }
 
+struct diff_line_range *diff_line_range_clone(struct diff_line_range *r)
+{
+	struct diff_line_range *ret = xmalloc(sizeof(*ret));
+	int i = 0;
+
+	DIFF_LINE_RANGE_INIT(ret);
+	ret->ranges = xcalloc(r->nr, sizeof(struct range));
+	memcpy(ret->ranges, r->ranges, sizeof(struct range) * r->nr);
+
+	ret->alloc = ret->nr = r->nr;
+
+	for (; i < ret->nr; i++)
+		PRINT_PAIR_INIT(&ret->ranges[i].pair);
+
+	ret->spec = r->spec;
+	assert(ret->spec);
+	ret->spec->count++;
+
+	return ret;
+}
+
+struct diff_line_range *diff_line_range_clone_deeply(struct diff_line_range *r)
+{
+	struct diff_line_range *ret = NULL;
+	struct diff_line_range *tmp = NULL, *prev = NULL;
+
+	assert(r);
+	ret = tmp = prev = diff_line_range_clone(r);
+	r = r->next;
+	while (r) {
+		tmp = diff_line_range_clone(r);
+		prev->next = tmp;
+		prev = tmp;
+		r = r->next;
+	}
+
+	return ret;
+}
+
 struct diff_line_range *diff_line_range_merge(struct diff_line_range *out,
 		struct diff_line_range *other)
 {
diff --git a/line.h b/line.h
index 8b30ada..7563536 100644
--- a/line.h
+++ b/line.h
@@ -119,6 +119,10 @@ extern struct diff_line_range *diff_line_range_merge(
 		struct diff_line_range *out,
 		struct diff_line_range *other);
 
+extern struct diff_line_range *diff_line_range_clone(struct diff_line_range *r);
+
+extern struct diff_line_range *diff_line_range_clone_deeply(struct diff_line_range *r);
+
 extern void setup_line(struct rev_info *rev, struct diff_line_range *r);
 
 extern void add_line_range(struct rev_info *revs, struct commit *commit,
-- 
1.7.0.2.273.gc2413.dirty