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posixdir.c
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posixdir.c
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/*
** POSIXDIR.C - POSIX-style directory processing
**
** Original Copyright 1988-1991 by Bob Stout as part of
** the MicroFirm Function Library (MFL)
**
** The user is granted a free limited license to use this source file
** to create royalty-free programs, subject to the terms of the
** license restrictions specified in the LICENSE.MFL file.
*/
#include <string.h>
#include <stdlib.h>
#include <dos.h>
#include <io.h>
#include <errno.h>
#include "sniptype.h"
#include "dirent.h"
#include "filnames.h" /* For dos2unix() */
#define _NDIRS 20
int DFerr;
DIR _DIRS[_NDIRS]; /* Initialize DIR array to zeros */
/******************************************************************/
/* */
/* opendir() */
/* */
/* Function: Open a directory for reading. */
/* */
/* Parameters: 1 - Directory name. May include path spec. */
/* */
/* Returns: Pointer to a DIR typedef'ed structure, similar */
/* to fopen() returning a FILE pointer. */
/* */
/* NULL if error, DFerr set as follows: */
/* Success_ - No error */
/* ENOENT - Could not locate directory or contents */
/* ENOTDIR - Not a directory */
/* ENOMEM - Too many directories already open */
/* */
/* Side effects: The dd_size element of the DIR structure */
/* will contain a number representing the total */
/* number of entries in the directory. The */
/* dd_loc element will be set to zero since */
/* no elements have, as yet, been read. */
/* */
/******************************************************************/
DIR *opendir(char *fname)
{
int i;
unsigned n = 0;
char *p;
DOSFileData dstruct;
for (i = 0; i < _NDIRS; ++i)
{
if (!_DIRS[i].dd_fd)
break;
}
if (_NDIRS <= i)
{
DFerr = ENOMEM;
return NULL;
}
dos2unix(fname);
if (':' == fname[1] && 1 < strlen(fname))
p = &fname[2];
else p = fname;
while ('/' == LAST_CHAR(p) && 1 < strlen(p))
LAST_CHAR(p) = '\0';
if (strcmp(p, "/") && strlen(p))
{
if (Success_ != (FIND_FIRST(fname, _A_ANY, &_DIRS[i].dd_buf)))
{
DFerr = ENOENT;
return NULL;
}
if (!(_A_SUBDIR & _DIRS[i].dd_buf.attrib))
{
DFerr = ENOTDIR;
return NULL;
}
}
strcpy(_DIRS[i].dd_dirname, fname);
if (!strlen(p))
strcat(_DIRS[i].dd_dirname, ".");
if ('/' != LAST_CHAR(_DIRS[i].dd_dirname))
strcat(_DIRS[i].dd_dirname, "/");
strcat(strupr(_DIRS[i].dd_dirname), "*.*");
if (Success_ != FIND_FIRST(_DIRS[i].dd_dirname,
_A_ANY, &_DIRS[i].dd_buf))
{
DFerr = ENOENT;
return NULL;
}
memcpy(&dstruct, &_DIRS[i].dd_buf, sizeof(DOSFileData));
do
{
++n;
} while (Success_ == FIND_NEXT(&_DIRS[i].dd_buf));
memcpy(&_DIRS[i].dd_buf, &dstruct, sizeof(DOSFileData));
_DIRS[i].dd_size = n;
_DIRS[i].dd_loc = 0;
_DIRS[i].dd_fd = i + 1;
DFerr = Success_;
return &_DIRS[i];
}
/******************************************************************/
/* */
/* closedir() */
/* */
/* Function: Close a previously opened directory. */
/* */
/* Parameters: 1 - DIR pointer of directory to close. */
/* */
/* Returns: Success_ or Error_. */
/* */
/******************************************************************/
int closedir(DIR *dirp)
{
if (0 == dirp->dd_fd || _NDIRS < dirp->dd_fd)
{
DFerr = EBADF;
return Error_;
}
FIND_END(dirp->dd_buf);
memset(dirp, 0, sizeof(DIR));
return Success_;
}
/******************************************************************/
/* */
/* rewinddir() */
/* */
/* Function: Reset an open DIR to its first entry. */
/* */
/* Parameters: 1 - DIR pointer of directory to rewind. */
/* */
/* Returns: Success_ or Error_. */
/* */
/******************************************************************/
int rewinddir(DIR *dirp)
{
if (0 == dirp->dd_fd || _NDIRS < dirp->dd_fd)
{
DFerr = EBADF;
return Error_;
}
FIND_FIRST(dirp->dd_dirname, _A_ANY, &(dirp->dd_buf));
dirp->dd_loc = 0;
return Success_;
}
/******************************************************************/
/* */
/* seekdir() */
/* */
/* Function: Point to a selected entry in a DIR. */
/* */
/* Parameters: 1 - DIR pointer of directory to rewind. */
/* 2 - Offset of entry to seek */
/* 3 - Origin of offset */
/* */
/* Returns: A DOSFileData pointer, same as returned by DOS find */
/* first/next calls. */
/* */
/* NULL if error, DFerr set as follows: */
/* Success_ - No error */
/* EBADF - Bad file (DIR) pointer */
/* EACCES - Illegal origin specification */
/* EOF - Attempt to seek past end of directory */
/* */
/******************************************************************/
DOSFileData *seekdir(DIR *dirp, int offset, int origin)
{
int i, loc;
if (0 == dirp->dd_fd || _NDIRS < dirp->dd_fd)
{
DFerr = EBADF;
return NULL;
}
switch (origin)
{
case SEEK_SET:
loc = offset + 1;
break;
case SEEK_CUR:
loc = dirp->dd_loc + offset;
break;
case SEEK_END:
loc = dirp->dd_size + offset;
break;
default:
DFerr = EACCES;
return NULL;
}
if (loc > (int)dirp->dd_size || 0 >= loc)
{
DFerr = EOF;
return NULL;
}
rewinddir(dirp);
for (i = 0; i < loc; ++i)
readdir(dirp);
DFerr = Success_;
return (&(dirp->dd_buf));
}
/******************************************************************/
/* */
/* readdir() */
/* */
/* Function: Reads entries from an open directory. */
/* */
/* Parameters: 1 - DIR pointer of directory to read. */
/* */
/* Returns: A DOSFileData pointer, same as returned by DOS find */
/* first/next calls. */
/* */
/* NULL if error, DFerr set as follows: */
/* Success_ - No error */
/* EBADF - Bad file (DIR) pointer */
/* EOF - Attempt to read past end of directory */
/* */
/* Side effects: The dd_loc element of the DIR structure */
/* will contain a number representing which */
/* element of the directory was returned. It may */
/* range from 1 to dd_size. */
/* */
/******************************************************************/
DOSFileData *readdir(DIR *dirp)
{
if (0 == dirp->dd_fd || _NDIRS < dirp->dd_fd)
{
DFerr = EBADF;
return NULL;
}
if (0 == dirp->dd_loc || Success_ == FIND_NEXT(&(dirp->dd_buf)))
{
dirp->dd_loc += 1;
DFerr = Success_;
return (&(dirp->dd_buf));
}
else
{
DFerr = EOF;
return NULL;
}
}