Method nextCluster

src/core/FatSystem.cpp:199–259

* Returns the 32-bit fat value for the given cluster number */

 * Returns the 32-bit fat value for the given cluster number
 */
unsigned int FatSystem::nextCluster(unsigned int cluster, int fat)
{
    int bytes = (bits == 32 ? 4 : 2);
#ifndef __WIN__
    char buffer[bytes];
#else
    char *buffer = new char[bytes];
    __try
    {
#endif

    if (!validCluster(cluster)) {
        return 0;
    }

    if (cacheEnabled) {
        return cache[cluster];
    }

    readData(fatStart+fatSize*fat+(bits*cluster)/8, buffer, sizeof(buffer));

    unsigned int next;

    if (type == FAT32) {
        next = FAT_READ_LONG(buffer, 0)&0x0fffffff;

        if (next >= 0x0ffffff0) {
            return FAT_LAST;
        } else {
            return next;
        }
    } else {
        next = FAT_READ_SHORT(buffer,0)&0xffff;

        if (bits == 12) {
            int bit = cluster*bits;
            if (bit%8 != 0) {
                next = next >> 4;
            }
            next &= 0xfff;
            if (next >= 0xff0) {
                return FAT_LAST;
            } else {
                return next;
            }
        } else {
            if (next >= 0xfff0) {
                return FAT_LAST;
            } else {
                return next;
            }
        }
    }
#ifdef __WIN__
}
__finally
{
    delete[] buffer;