_readdir.c

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/*      readdir()                                       Author: Kees J. Bot
 *                                                              24 Apr 1989
 */
#define nil 0
#include <lib.h>
#define read    _read
#define readdir _readdir
#include <sys/types.h>
#include <sys/stat.h>
#include <dirent.h>
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#include <limits.h>
#include <errno.h>
#include <string.h>

#define v7ent(p)        ((struct _v7_direct *) (p))
#define V7_EXTENT       (sizeof(struct _v7_direct) / sizeof(struct _fl_direct) - 1)

struct dirent *readdir(DIR *dp)
/* Return the next entry in a directory.  Handle V7 and FLEX format dirs. */
{
        struct dirent *e;

        if (dp == nil) { errno= EBADF; return nil; }

        do {
                if (dp->_count <= 0) {
                        /* Read the next directory block. */
                        dp->_count= read(dp->_fd, dp->_buf, sizeof(dp->_buf));
                        if (dp->_count <= 0) return nil;

                        dp->_count/= sizeof(dp->_buf[0]);
                        dp->_ptr= dp->_buf;

                        /* Extent is zero of the first flex entry. */
                        if (dp->_v7 == (char)-1) dp->_v7= dp->_buf[0].d_extent;
                }

                if (!dp->_v7) {
                        /* FLEX. */
                        e= (struct dirent *) dp->_ptr;
                } else {
                        /* V7: transform to FLEX. */
                        e= (struct dirent *) dp->_v7f;
                        e->d_ino= v7ent(dp->_ptr)->d_ino;
                        e->d_extent= V7_EXTENT;
                        memcpy(e->d_name, v7ent(dp->_ptr)->d_name, DIRSIZ);
                        e->d_name[DIRSIZ]= 0;
                }

                dp->_ptr+= 1 + e->d_extent;
                dp->_count-= 1 + e->d_extent;
                dp->_pos+= (1 + e->d_extent) * sizeof(*dp->_ptr);

        } while (e->d_ino == 0);
        return e;
}

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