Method Realloc

include/cereal/external/rapidjson/allocators.h:204–235

Resizes a memory block (concept Allocator)

    //! Resizes a memory block (concept Allocator)
    void* Realloc(void* originalPtr, size_t originalSize, size_t newSize) {
        if (originalPtr == 0)
            return Malloc(newSize);

        if (newSize == 0)
            return NULL;

        originalSize = CEREAL_RAPIDJSON_ALIGN(originalSize);
        newSize = CEREAL_RAPIDJSON_ALIGN(newSize);

        // Do not shrink if new size is smaller than original
        if (originalSize >= newSize)
            return originalPtr;

        // Simply expand it if it is the last allocation and there is sufficient space
        if (originalPtr == reinterpret_cast<char *>(chunkHead_) + CEREAL_RAPIDJSON_ALIGN(sizeof(ChunkHeader)) + chunkHead_->size - originalSize) {
            size_t increment = static_cast<size_t>(newSize - originalSize);
            if (chunkHead_->size + increment <= chunkHead_->capacity) {
                chunkHead_->size += increment;
                return originalPtr;
            }
        }

        // Realloc process: allocate and copy memory, do not free original buffer.
        if (void* newBuffer = Malloc(newSize)) {
            if (originalSize)
                std::memcpy(newBuffer, originalPtr, originalSize);
            return newBuffer;
        }
        else
            return NULL;
    }

    //! Frees a memory block (concept Allocator)
    static void Free(void *ptr) { (void)ptr; } // Do nothing