Merge pull request #305 from pah/fix/strict-memcpy

Avoid calling memcpy with NULL pointers

include/rapidjson/allocators.h

@@ -160,6 +160,9 @@ public:
 
     //! Allocates a memory block. (concept Allocator)
     void* Malloc(size_t size) {
+        if (!size)
+            return NULL;
+
         size = RAPIDJSON_ALIGN(size);
         if (chunkHead_ == 0 || chunkHead_->size + size > chunkHead_->capacity)
             AddChunk(chunk_capacity_ > size ? chunk_capacity_ : size);
@@ -191,7 +194,9 @@ public:
         // Realloc process: allocate and copy memory, do not free original buffer.
         void* newBuffer = Malloc(newSize);
         RAPIDJSON_ASSERT(newBuffer != 0);   // Do not handle out-of-memory explicitly.
-        return std::memcpy(newBuffer, originalPtr, originalSize);
+        if (originalSize)
+            std::memcpy(newBuffer, originalPtr, originalSize);
+        return newBuffer;
     }
 
     //! Frees a memory block (concept Allocator)

include/rapidjson/document.h

@@ -1579,16 +1579,24 @@ private:
     // Initialize this value as array with initial data, without calling destructor.
     void SetArrayRaw(GenericValue* values, SizeType count, Allocator& allocator) {
         flags_ = kArrayFlag;
-        data_.a.elements = (GenericValue*)allocator.Malloc(count * sizeof(GenericValue));
-        std::memcpy(data_.a.elements, values, count * sizeof(GenericValue));
+        if (count) {
+            data_.a.elements = (GenericValue*)allocator.Malloc(count * sizeof(GenericValue));
+            std::memcpy(data_.a.elements, values, count * sizeof(GenericValue));
+        }
+        else
+            data_.a.elements = NULL;
         data_.a.size = data_.a.capacity = count;
     }
 
     //! Initialize this value as object with initial data, without calling destructor.
     void SetObjectRaw(Member* members, SizeType count, Allocator& allocator) {
         flags_ = kObjectFlag;
-        data_.o.members = (Member*)allocator.Malloc(count * sizeof(Member));
-        std::memcpy(data_.o.members, members, count * sizeof(Member));
+        if (count) {
+            data_.o.members = (Member*)allocator.Malloc(count * sizeof(Member));
+            std::memcpy(data_.o.members, members, count * sizeof(Member));
+        }
+        else
+            data_.o.members = NULL;
         data_.o.size = data_.o.capacity = count;
     }