Introduce BMessage::CompareData() which is a Haiku API extension. It compares

the data of two BMessages and allows recursive comparison (BMessage inside
BMessage). Note that using this API might require you to recompile your app in
the path to R1.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@28174 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/os/app/Message.h

@@ -216,6 +216,10 @@ class BMessage {
 		status_t		ReplaceData(const char *name, type_code type, int32 index,
 							const void *data, ssize_t numBytes);
 
+		// Compareing data (only) - Haiku experimental API
+		bool			CompareData(const BMessage &other,
+							bool ignoreFieldOrder = true, bool deep = false) const;
+
 		void			*operator new(size_t size);
 		void			*operator new(size_t, void *pointer);
 		void			operator delete(void *pointer, size_t size);

src/kits/app/Message.cpp

@@ -220,6 +220,65 @@ BMessage::operator delete(void *pointer, size_t size)
 }
 
 
+bool
+BMessage::CompareData(const BMessage &other, bool ignoreFieldOrder,
+	bool deep) const
+{
+	if (this == &other)
+		return true;
+
+	if (fHeader->field_count != other.fHeader->field_count)
+		return false;
+
+	for (int32 i = 0; i < fHeader->field_count; i++) {
+		field_header *field = &fFields[i];
+		field_header *otherField = NULL;
+
+		const char *name = (const char *)fData + field->offset;
+		if (ignoreFieldOrder) {
+			if (other._FindField(name, B_ANY_TYPE, &otherField) != B_OK)
+				return false;
+		} else {
+			otherField = &other.fFields[i];
+			if (otherField->name_length != field->name_length)
+				return false;
+
+			const char *otherName = (const char *)other.fData
+				+ otherField->offset;
+			if (strncmp(name, otherName, field->name_length) != 0)
+				return false;
+		}
+
+		if (otherField->type != field->type || otherField->count != field->count)
+			return false;
+
+		uint8 *data = fData + field->offset + field->name_length;
+		uint8 *otherData = other.fData + otherField->offset
+			+ otherField->name_length;
+
+		bool needsMemCompare = true;
+		if (deep && field->type == B_MESSAGE_TYPE) {
+			BMessage message, otherMessage;
+			if (message.Unflatten((const char *)data) == B_OK
+				&& otherMessage.Unflatten((const char *)otherData) == B_OK) {
+				if (!message.CompareData(ignoreFieldOrder, deep))
+					return false;
+				needsMemCompare = false;
+			}
+		}
+
+		if (needsMemCompare) {
+			if (otherField->data_size != field->data_size)
+				return false;
+			if (memcmp(data, otherData, field->data_size) != 0)
+				return false;
+		}
+	}
+
+	return true;
+}
+
+
 status_t
 BMessage::_InitCommon(bool initHeader)
 {