Fixed a few cppcheck warnings.

C-style cast
Add function const to MemoryPoolAllocator::Capacity() and Size()

include/rapidjson/allocators.h

@@ -130,7 +130,7 @@ public:
 	//! Computes the total capacity of allocated memory chunks.
 	/*! \return total capacity in bytes.
 	*/
-	size_t Capacity() {
+	size_t Capacity() const {
 		size_t capacity = 0;
 		for (ChunkHeader* c = chunkHead_; c != 0; c = c->next)
 			capacity += c->capacity;
@@ -140,7 +140,7 @@ public:
 	//! Computes the memory blocks allocated.
 	/*! \return total used bytes.
 	*/
-	size_t Size() {
+	size_t Size() const {
 		size_t size = 0;
 		for (ChunkHeader* c = chunkHead_; c != 0; c = c->next)
 			size += c->size;
@@ -196,7 +196,7 @@ private:
 	/*! \param capacity Capacity of the chunk in bytes.
 	*/
 	void AddChunk(size_t capacity) {
-		ChunkHeader* chunk = (ChunkHeader*)baseAllocator_->Malloc(sizeof(ChunkHeader) + capacity);
+		ChunkHeader* chunk = reinterpret_cast<ChunkHeader*>(baseAllocator_->Malloc(sizeof(ChunkHeader) + capacity));
 		chunk->capacity = capacity;
 		chunk->size = 0;
 		chunk->next = chunkHead_;

include/rapidjson/document.h

@@ -518,12 +518,12 @@ public:
 		if (o.size >= o.capacity) {
 			if (o.capacity == 0) {
 				o.capacity = kDefaultObjectCapacity;
-				o.members = (Member*)allocator.Malloc(o.capacity * sizeof(Member));
+				o.members = reinterpret_cast<Member*>(allocator.Malloc(o.capacity * sizeof(Member)));
 			}
 			else {
 				SizeType oldCapacity = o.capacity;
 				o.capacity *= 2;
-				o.members = (Member*)allocator.Realloc(o.members, oldCapacity * sizeof(Member), o.capacity * sizeof(Member));
+				o.members = reinterpret_cast<Member*>(allocator.Realloc(o.members, oldCapacity * sizeof(Member), o.capacity * sizeof(Member)));
 			}
 		}
 		o.members[o.size].name.RawAssign(name);