[PATCH 1/8] sha1-array: provide oid_array_filter

[Stefan Beller <sbeller@google.com>]

Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
---
 sha1-array.c | 17 +++++++++++++++++
 sha1-array.h |  9 +++++++++
 2 files changed, 26 insertions(+)

diff --git a/sha1-array.c b/sha1-array.c
index b94e0ec0f5e..d922e94e3fc 100644
--- a/sha1-array.c
+++ b/sha1-array.c
@@ -77,3 +77,20 @@ int oid_array_for_each_unique(struct oid_array *array,
 	}
 	return 0;
 }
+
+void oid_array_filter(struct oid_array *array,
+		      for_each_oid_fn want,
+		      void *cb_data)
+{
+	unsigned nr = array->nr, src, dst;
+	struct object_id *oids = array->oid;
+
+	for (src = dst = 0; src < nr; src++) {
+		if (want(&oids[src], cb_data)) {
+			if (src != dst)
+				oidcpy(&oids[dst], &oids[src]);
+			dst++;
+		}
+	}
+	array->nr = dst;
+}
diff --git a/sha1-array.h b/sha1-array.h
index 232bf950172..275e5b02f5e 100644
--- a/sha1-array.h
+++ b/sha1-array.h
@@ -23,4 +23,13 @@ int oid_array_for_each_unique(struct oid_array *array,
 			      for_each_oid_fn fn,
 			      void *data);
 
+/*
+ * Apply want to each entry in array, retaining only the entries for
+ * which the function returns true.  Preserve the order of the entries
+ * that are retained.
+ */
+void oid_array_filter(struct oid_array *array,
+		      for_each_oid_fn want,
+		      void *cbdata);
+
 #endif /* SHA1_ARRAY_H */
-- 
2.19.0.444.g18242da7ef-goog