Merge "libmedia: add NULL check before accessing source and destination buffers."

            ALOGE("got %zu, but memory has %zu", len, mMemory->size());

            return ERROR_OUT_OF_RANGE;

        }

        if(buffer == NULL) {

           ALOGE("readAt got a NULL buffer");

           return UNKNOWN_ERROR;

        }

        if (mMemory->pointer() == NULL) {

           ALOGE("readAt got a NULL mMemory->pointer()");

           return UNKNOWN_ERROR;

        }

        memcpy(buffer, mMemory->pointer(), len);