[PATCH v1 1/3] libcamera: controls: Give name to the union containing storage

[Barnabás Pőcze]

In order to be able to copy the storage as one unit, regardless of
which member is active give a name to the union member.

Signed-off-by: Barnabás Pőcze <barnabas.pocze at ideasonboard.com>
---
 include/libcamera/controls.h |  6 +++---
 src/libcamera/controls.cpp   | 17 ++++++++---------
 2 files changed, 11 insertions(+), 12 deletions(-)

diff --git a/include/libcamera/controls.h b/include/libcamera/controls.h
index 4bfe9615c..1dc6ccffa 100644
--- a/include/libcamera/controls.h
+++ b/include/libcamera/controls.h
@@ -238,9 +238,9 @@ private:
 	bool isArray_;
 	std::size_t numElements_ : 32;
 	union {
-		uint64_t value_;
-		void *storage_;
-	};
+		uint64_t internal;
+		void *external;
+	} storage_;
 
 	void release();
 	void set(ControlType type, bool isArray, const void *data,
diff --git a/src/libcamera/controls.cpp b/src/libcamera/controls.cpp
index 70f6f6092..d384e1ef7 100644
--- a/src/libcamera/controls.cpp
+++ b/src/libcamera/controls.cpp
@@ -10,6 +10,7 @@
 #include <sstream>
 #include <string.h>
 #include <string>
+#include <utility>
 
 #include <libcamera/base/log.h>
 #include <libcamera/base/utils.h>
@@ -122,10 +123,8 @@ void ControlValue::release()
 {
 	std::size_t size = numElements_ * ControlValueSize[type_];
 
-	if (size > sizeof(value_)) {
-		delete[] reinterpret_cast<uint8_t *>(storage_);
-		storage_ = nullptr;
-	}
+	if (size > sizeof(storage_.internal))
+		delete[] reinterpret_cast<uint8_t *>(std::exchange(storage_.external, nullptr));
 }
 
 ControlValue::~ControlValue()
@@ -192,9 +191,9 @@ ControlValue &ControlValue::operator=(const ControlValue &other)
 Span<const uint8_t> ControlValue::data() const
 {
 	std::size_t size = numElements_ * ControlValueSize[type_];
-	const uint8_t *data = size > sizeof(value_)
-			    ? reinterpret_cast<const uint8_t *>(storage_)
-			    : reinterpret_cast<const uint8_t *>(&value_);
+	const uint8_t *data = size > sizeof(storage_.internal)
+			    ? reinterpret_cast<const uint8_t *>(storage_.external)
+			    : reinterpret_cast<const uint8_t *>(&storage_.internal);
 	return { data, size };
 }
 
@@ -391,8 +390,8 @@ void ControlValue::reserve(ControlType type, bool isArray, std::size_t numElemen
 	if (oldSize == newSize)
 		return;
 
-	if (newSize > sizeof(value_))
-		storage_ = reinterpret_cast<void *>(new uint8_t[newSize]);
+	if (newSize > sizeof(storage_.internal))
+		storage_.external = new uint8_t[newSize];
 }
 
 /**
-- 
2.49.0