Munging data four bytes at a time

void Munge32( void *data, uint32_t size ) {
    uint32_t *data32 = (uint32_t*) data;
    uint32_t *data32End = data32 + (size >> 2); /* Divide size by 4. */
    uint8_t *data8 = (uint8_t*) data32End;
    uint8_t *data8End = data8 + (size & 0x00000003); /* Strip upper 30 bits. */
    
    while( data32 != data32End ) {
        *data32++ = -*data32;
    }
    while( data8 != data8End ) {
        *data8++ = -*data8;
    }
}