From 2b1809e9d384c143487ef6065af0cf0112669b06 Mon Sep 17 00:00:00 2001
From: He Junyan <junyan.he@hotmail.com>
Date: Fri, 10 Apr 2020 21:21:43 +0800
Subject: [PATCH] libs: video-format: add a helper function of
 get_formats_by_chroma.

The function iterates all supported video formats and returns the
formats belong to the specified chroma type.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer-vaapi/-/merge_requests/315>
---
 gst-libs/gst/vaapi/video-format.c | 33 +++++++++++++++++++++++++++++++
 gst-libs/gst/vaapi/video-format.h |  3 +++
 2 files changed, 36 insertions(+)

diff --git a/gst-libs/gst/vaapi/video-format.c b/gst-libs/gst/vaapi/video-format.c
index 5ebb211ccb..6c1e8e7f5d 100644
--- a/gst-libs/gst/vaapi/video-format.c
+++ b/gst-libs/gst/vaapi/video-format.c
@@ -476,6 +476,39 @@ gst_vaapi_video_format_get_best_native (GstVideoFormat format)
   return gst_vaapi_video_format_from_chroma (chroma_type);
 }
 
+/**
+ * gst_vaapi_video_format_get_formats_by_chroma:
+ * @chroma: a #GstVaapiChromaType
+ *
+ * Get all #GstVideoFormat which belong to #GstVaapiChromaType.
+ *
+ * Returns: an array of #GstVideoFormat.
+ **/
+GArray *
+gst_vaapi_video_format_get_formats_by_chroma (guint chroma)
+{
+  const GstVideoFormatMap *entry;
+  GArray *formats;
+  guint i;
+
+  formats = g_array_new (FALSE, FALSE, sizeof (GstVideoFormat));
+  if (!formats)
+    return NULL;
+
+  for (i = 0; i < gst_vaapi_video_formats_map->len; i++) {
+    entry = &g_array_index (gst_vaapi_video_formats_map, GstVideoFormatMap, i);
+    if (entry->chroma_type == chroma)
+      g_array_append_val (formats, entry->format);
+  }
+
+  if (formats->len == 0) {
+    g_array_unref (formats);
+    return NULL;
+  }
+
+  return formats;
+}
+
 struct ImageFormatsData
 {
   VAImageFormat *formats;
diff --git a/gst-libs/gst/vaapi/video-format.h b/gst-libs/gst/vaapi/video-format.h
index 466e115a2d..953194e559 100644
--- a/gst-libs/gst/vaapi/video-format.h
+++ b/gst-libs/gst/vaapi/video-format.h
@@ -64,6 +64,9 @@ gst_vaapi_video_format_from_chroma (guint chroma);
 GstVideoFormat
 gst_vaapi_video_format_get_best_native (GstVideoFormat format);
 
+GArray *
+gst_vaapi_video_format_get_formats_by_chroma (guint chroma);
+
 gboolean
 gst_vaapi_video_format_create_map (VAImageFormat * formats, guint n);