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Annotation of 42BSD/lib/libc/gen/scandir.c, revision 1.1.1.1

1.1       root        1: #ifndef lint
                      2: static char sccsid[] = "@(#)scandir.c  4.2 (Berkeley) 7/1/83";
                      3: #endif
                      4: 
                      5: /*
                      6:  * Scan the directory dirname calling select to make a list of selected
                      7:  * directory entries then sort using qsort and compare routine dcomp.
                      8:  * Returns the number of entries and a pointer to a list of pointers to
                      9:  * struct direct (through namelist). Returns -1 if there were any errors.
                     10:  */
                     11: 
                     12: #include <sys/types.h>
                     13: #include <sys/stat.h>
                     14: #include <sys/dir.h>
                     15: 
                     16: scandir(dirname, namelist, select, dcomp)
                     17:        char *dirname;
                     18:        struct direct *(*namelist[]);
                     19:        int (*select)(), (*dcomp)();
                     20: {
                     21:        register struct direct *d, *p, **names;
                     22:        register int nitems;
                     23:        register char *cp1, *cp2;
                     24:        struct stat stb;
                     25:        long arraysz;
                     26:        DIR *dirp;
                     27: 
                     28:        if ((dirp = opendir(dirname)) == NULL)
                     29:                return(-1);
                     30:        if (fstat(dirp->dd_fd, &stb) < 0)
                     31:                return(-1);
                     32: 
                     33:        /*
                     34:         * estimate the array size by taking the size of the directory file
                     35:         * and dividing it by a multiple of the minimum size entry. 
                     36:         */
                     37:        arraysz = (stb.st_size / 24);
                     38:        names = (struct direct **)malloc(arraysz * sizeof(struct direct *));
                     39:        if (names == NULL)
                     40:                return(-1);
                     41: 
                     42:        nitems = 0;
                     43:        while ((d = readdir(dirp)) != NULL) {
                     44:                if (select != NULL && !(*select)(d))
                     45:                        continue;       /* just selected names */
                     46:                /*
                     47:                 * Make a minimum size copy of the data
                     48:                 */
                     49:                p = (struct direct *)malloc(DIRSIZ(d));
                     50:                if (p == NULL)
                     51:                        return(-1);
                     52:                p->d_ino = d->d_ino;
                     53:                p->d_reclen = d->d_reclen;
                     54:                p->d_namlen = d->d_namlen;
                     55:                for (cp1 = p->d_name, cp2 = d->d_name; *cp1++ = *cp2++; );
                     56:                /*
                     57:                 * Check to make sure the array has space left and
                     58:                 * realloc the maximum size.
                     59:                 */
                     60:                if (++nitems >= arraysz) {
                     61:                        names = (struct direct **)realloc((char *)names,
                     62:                                (stb.st_size/12) * sizeof(struct direct *));
                     63:                        if (names == NULL)
                     64:                                return(-1);
                     65:                }
                     66:                names[nitems-1] = p;
                     67:        }
                     68:        closedir(dirp);
                     69:        if (nitems && dcomp != NULL)
                     70:                qsort(names, nitems, sizeof(struct direct *), dcomp);
                     71:        *namelist = names;
                     72:        return(nitems);
                     73: }
                     74: 
                     75: /*
                     76:  * Alphabetic order comparison routine for those who want it.
                     77:  */
                     78: alphasort(d1, d2)
                     79:        struct direct **d1, **d2;
                     80: {
                     81:        return(strcmp((*d1)->d_name, (*d2)->d_name));
                     82: }

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