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