android: metadata: Add hasEntry and entryContains

Add convenience functions for checking if an entry is present in a
CameraMetadata instance, and to check if an array entry includes a
specific value.

Signed-off-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

src/android/camera_metadata.cpp

@@ -121,6 +121,26 @@ bool CameraMetadata::resize(size_t count, size_t size)
 	return true;
 }
 
+template<> bool CameraMetadata::entryContains(uint32_t tag, uint8_t value) const
+{
+	camera_metadata_ro_entry_t entry;
+	if (!getEntry(tag, &entry))
+		return false;
+
+	for (unsigned int i = 0; i < entry.count; i++) {
+		if (entry.data.u8[i] == value)
+			return true;
+	}
+
+	return false;
+}
+
+bool CameraMetadata::hasEntry(uint32_t tag) const
+{
+	camera_metadata_ro_entry_t entry;
+	return getEntry(tag, &entry);
+}
+
 bool CameraMetadata::addEntry(uint32_t tag, const void *data, size_t count,
 			      size_t elementSize)
 {

src/android/camera_metadata.h

@@ -29,6 +29,10 @@ public:
 	bool isValid() const { return valid_; }
 	bool getEntry(uint32_t tag, camera_metadata_ro_entry_t *entry) const;
 
+	template<typename T> bool entryContains(uint32_t tag, T value) const;
+
+	bool hasEntry(uint32_t tag) const;
+
 	template<typename T,
 		 std::enable_if_t<std::is_arithmetic_v<T>> * = nullptr>
 	bool addEntry(uint32_t tag, const T &data)