Function ReadLittleInt32

include/bmpread/bmpread.c:152–171

Reads a little-endian int32_t from fp and stores the result in *dest in the * host's byte order. Returns 0 on EOF or nonzero on success. */

 * host's byte order.  Returns 0 on EOF or nonzero on success.
 */
static int ReadLittleInt32(int32_t * dest, FILE * fp)
{
    /* I *believe* casting unsigned -> signed is implementation-defined when
     * the unsigned value is out of range for the signed type, which would be
     * the case for any negative number we've just read out of the file into a
     * uint.  This is a portable way to "reinterpret" the bits as signed
     * without running into undefined/implementation-defined behavior.  I
     * think.
     */
    union int32_signedness_swap
    {
        uint32_t uint32;
        int32_t  int32;

    } t;

    if(!ReadLittleBytes(&t.uint32, 4, fp)) return 0;
    *dest = t.int32;
    return 1;
}

/* Reads a little-endian uint16_t from fp and stores the result in *dest in the
 * host's byte order.  Returns 0 on EOF or nonzero n success.