# HG changeset patch
# User František Kučera <franta-hg@frantovo.cz>
# Date 1514047952 -3600
# Node ID 4975c24cc361c3f0e3103ac1618f3d1fa2dd0376
# Parent  8f0a5552db789132b6b9990c620777145a74d19d
check memory bounds in read() and write()

diff -r 8f0a5552db78 -r 4975c24cc361 c++/rgb-assembler/rgb-assembler.cpp
--- a/c++/rgb-assembler/rgb-assembler.cpp	Sat Dec 23 17:33:49 2017 +0100
+++ b/c++/rgb-assembler/rgb-assembler.cpp	Sat Dec 23 17:52:32 2017 +0100
@@ -76,6 +76,12 @@
 
 // TODO: more commands, better numbers
 
+template<typename T> T logMemoryError(const address_t &index) {
+	wprintf(L"memory error: index = %d, sizeof(T) = %d, MEMORY_SIZE = %d\n", index, sizeof (T), MEMORY_SIZE);
+	// TODO: return error value or throw exception
+	return T();
+}
+
 /**
  * Reads data on given position in memory and increments the index (position).
  * 
@@ -84,10 +90,14 @@
  * @return value found at given position
  */
 template<typename T> T read(octet_t * memory, address_t &index) {
-	// TODO: for addresses: map higher memory to static hardcoded areas or peripherals
-	T * value = reinterpret_cast<T*> (memory + index);
-	index += sizeof (T);
-	return *value;
+	// TODO: map higher memory to static hardcoded areas or peripherals
+	if (index + sizeof (T) <= MEMORY_SIZE) {
+		T * value = reinterpret_cast<T*> (memory + index);
+		index += sizeof (T);
+		return *value;
+	} else {
+		return logMemoryError<T>(index);
+	}
 }
 
 /**
@@ -96,10 +106,14 @@
  * @param index offset in same units as memory type
  * @param value value to be written at given position
  */
-template<typename T> void write(octet_t * memory, address_t &index, const T value) {
-	T * m = reinterpret_cast<T*> (memory + index);
-	*m = value;
-	index += sizeof (value);
+template<typename T> T write(octet_t * memory, address_t &index, const T value) {
+	if (index + sizeof (T) <= MEMORY_SIZE) {
+		T * m = reinterpret_cast<T*> (memory + index);
+		*m = value;
+		index += sizeof (value);
+	} else {
+		return logMemoryError<T>(index);
+	}
 }
 
 int main(int argc, char* argv[]) {