Add maxCapacity constructor parameter to MemoryDataStream

Sming/Core/Data/Stream/MemoryDataStream.cpp

@@ -21,6 +21,10 @@ MemoryDataStream::MemoryDataStream(String&& string) noexcept
 bool MemoryDataStream::ensureCapacity(size_t minCapacity)
 {
 	if(capacity < minCapacity) {
+		if(minCapacity > maxCapacity) {
+			debug_e("MemoryDataStream too large, requested %u limit is %u", minCapacity, maxCapacity);
+			return false;
+		}
 		size_t newCapacity = minCapacity;
 		if(capacity != 0) {
 			// If expanding stream, increase buffer capacity in anticipation of further writes
@@ -30,6 +34,7 @@ bool MemoryDataStream::ensureCapacity(size_t minCapacity)
 		// realloc can fail, store the result in temporary pointer
 		auto newBuffer = (char*)realloc(buffer, newCapacity);
 		if(newBuffer == nullptr) {
+			debug_e("MemoryDataStream realloc(%u) failed", newCapacity);
 			return false;
 		}
 

Sming/Core/Data/Stream/MemoryDataStream.h

@@ -26,7 +26,9 @@
 class MemoryDataStream : public ReadWriteStream
 {
 public:
-	MemoryDataStream() = default;
+	MemoryDataStream(size_t maxCapacity = UINT16_MAX) : maxCapacity(maxCapacity)
+	{
+	}
 
 	/**
 	 * @brief Stream takes ownership of String content using move semantics
@@ -103,8 +105,9 @@ class MemoryDataStream : public ReadWriteStream
 	}
 
 private:
-	char* buffer = nullptr; ///< Stream content stored here
-	size_t readPos = 0;		///< Offset to current read position
-	size_t size = 0;		///< Number of bytes stored in stream (i.e. the write position)
-	size_t capacity = 0;	///< Number of bytes allocated in buffer
+	char* buffer = nullptr;			///< Stream content stored here
+	size_t maxCapacity{UINT16_MAX}; ///< Limit size of stream
+	size_t readPos = 0;				///< Offset to current read position
+	size_t size = 0;				///< Number of bytes stored in stream (i.e. the write position)
+	size_t capacity = 0;			///< Number of bytes allocated in buffer
 };

Sming/Wiring/FIFO.h

@@ -73,8 +73,10 @@ template <typename T, int rawSize> bool FIFO<T, rawSize>::enqueue(T element)
 	}
 	numberOfElements++;
 	raw[nextIn] = element;
-	if(++nextIn >= rawSize) // advance to next index, wrap if needed
+	// advance to next index, wrap if needed
+	if(++nextIn >= rawSize) {
 		nextIn = 0;
+	}
 	return true;
 }