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Annotation of 43BSDReno/lib/libc/gen/scandir.c, revision 1.1.1.1

1.1       root        1: /*
                      2:  * Copyright (c) 1983 Regents of the University of California.
                      3:  * All rights reserved.
                      4:  *
                      5:  * Redistribution and use in source and binary forms are permitted provided
                      6:  * that: (1) source distributions retain this entire copyright notice and
                      7:  * comment, and (2) distributions including binaries display the following
                      8:  * acknowledgement:  ``This product includes software developed by the
                      9:  * University of California, Berkeley and its contributors'' in the
                     10:  * documentation or other materials provided with the distribution and in
                     11:  * all advertising materials mentioning features or use of this software.
                     12:  * Neither the name of the University nor the names of its contributors may
                     13:  * be used to endorse or promote products derived from this software without
                     14:  * specific prior written permission.
                     15:  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
                     16:  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
                     17:  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
                     18:  */
                     19: 
                     20: #if defined(LIBC_SCCS) && !defined(lint)
                     21: static char sccsid[] = "@(#)scandir.c  5.9 (Berkeley) 6/24/90";
                     22: #endif /* LIBC_SCCS and not lint */
                     23: 
                     24: /*
                     25:  * Scan the directory dirname calling select to make a list of selected
                     26:  * directory entries then sort using qsort and compare routine dcomp.
                     27:  * Returns the number of entries and a pointer to a list of pointers to
                     28:  * struct dirent (through namelist). Returns -1 if there were any errors.
                     29:  */
                     30: 
                     31: #include <sys/types.h>
                     32: #include <sys/stat.h>
                     33: #include <dirent.h>
                     34: 
                     35: /*
                     36:  * The DIRSIZ macro gives the minimum record length which will hold
                     37:  * the directory entry.  This requires the amount of space in struct dirent
                     38:  * without the d_name field, plus enough space for the name with a terminating
                     39:  * null byte (dp->d_namlen+1), rounded up to a 4 byte boundary.
                     40:  */
                     41: #undef DIRSIZ
                     42: #define DIRSIZ(dp) \
                     43:     ((sizeof (struct dirent) - (MAXNAMLEN+1)) + (((dp)->d_namlen+1 + 3) &~ 3))
                     44: 
                     45: scandir(dirname, namelist, select, dcomp)
                     46:        char *dirname;
                     47:        struct dirent ***namelist;
                     48:        int (*select)(), (*dcomp)();
                     49: {
                     50:        register struct dirent *d, *p, **names;
                     51:        register int nitems;
                     52:        struct stat stb;
                     53:        long arraysz;
                     54:        DIR *dirp;
                     55: 
                     56:        if ((dirp = opendir(dirname)) == NULL)
                     57:                return(-1);
                     58:        if (fstat(dirp->dd_fd, &stb) < 0)
                     59:                return(-1);
                     60: 
                     61:        /*
                     62:         * estimate the array size by taking the size of the directory file
                     63:         * and dividing it by a multiple of the minimum size entry. 
                     64:         */
                     65:        arraysz = (stb.st_size / 24);
                     66:        names = (struct dirent **)malloc(arraysz * sizeof(struct dirent *));
                     67:        if (names == NULL)
                     68:                return(-1);
                     69: 
                     70:        nitems = 0;
                     71:        while ((d = readdir(dirp)) != NULL) {
                     72:                if (select != NULL && !(*select)(d))
                     73:                        continue;       /* just selected names */
                     74:                /*
                     75:                 * Make a minimum size copy of the data
                     76:                 */
                     77:                p = (struct dirent *)malloc(DIRSIZ(d));
                     78:                if (p == NULL)
                     79:                        return(-1);
                     80:                p->d_ino = d->d_ino;
                     81:                p->d_reclen = d->d_reclen;
                     82:                p->d_namlen = d->d_namlen;
                     83:                bcopy(d->d_name, p->d_name, p->d_namlen + 1);
                     84:                /*
                     85:                 * Check to make sure the array has space left and
                     86:                 * realloc the maximum size.
                     87:                 */
                     88:                if (++nitems >= arraysz) {
                     89:                        if (fstat(dirp->dd_fd, &stb) < 0)
                     90:                                return(-1);     /* just might have grown */
                     91:                        arraysz = stb.st_size / 12;
                     92:                        names = (struct dirent **)realloc((char *)names,
                     93:                                arraysz * sizeof(struct dirent *));
                     94:                        if (names == NULL)
                     95:                                return(-1);
                     96:                }
                     97:                names[nitems-1] = p;
                     98:        }
                     99:        closedir(dirp);
                    100:        if (nitems && dcomp != NULL)
                    101:                qsort(names, nitems, sizeof(struct dirent *), dcomp);
                    102:        *namelist = names;
                    103:        return(nitems);
                    104: }
                    105: 
                    106: /*
                    107:  * Alphabetic order comparison routine for those who want it.
                    108:  */
                    109: alphasort(d1, d2)
                    110:        void *d1, *d2;
                    111: {
                    112:        return(strcmp((*(struct dirent **)d1)->d_name,
                    113:            (*(struct dirent **)d2)->d_name));
                    114: }

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