source: trunk/minix/commands/i386/mtools-3.9.7/streamcache.c@ 11

/*
 * streamcache.c
 * Managing a cache of open disks
 */

#include "sysincludes.h"
#include "msdos.h"
#include "mtools.h"
#include "vfat.h"
#include "fs.h"
#include "mainloop.h"
#include "plain_io.h"
#include "file.h"

static int is_initialized = 0;
static Stream_t *fss[256]; /* open drives */

static void finish_sc(void)
{
        int i;

        for(i=0; i<256; i++){
                if(fss[i] && fss[i]->refs != 1 )
                        fprintf(stderr,"Streamcache allocation problem:%c %d\n",
                                i, fss[i]->refs);
                FREE(&(fss[i]));
        }
}

static void init_streamcache(void)
{
        int i;

        if(is_initialized)
                return;
        is_initialized = 1;
        for(i=0; i<256; i++)
                fss[i]=0;
        atexit(finish_sc);
}

Stream_t *open_root_dir(char *drive, int flags)
{
        Stream_t *Fs;
        int i, k;

        init_streamcache();

        k = -1;
        for(i=0; i<256; i++) {
                if (fss[i] == NULL || strcmp(getDrive(fss[i]), drive) == 0) {
                        k = i;
                        break;
                }
        }

        if(k == -1) {
                fprintf(stderr, "Cannot initialize '%s:', out of table space\n",
                        drive);
                return NULL;
        }

        /* open the drive */
        if(fss[k])
                Fs = fss[k];
        else {
                Fs = fs_init(drive, flags);
                if (!Fs){
                        fprintf(stderr, "Cannot initialize '%s:'\n", drive);
                        return NULL;
                }

                fss[k] = Fs;
        }

        return OpenRoot(Fs);
}