ref: 25b70033bf57b57008b235a258c728efd13a08b2
dir: /win32/win_opendir.c/
//
// 03/10/2006 James Haley
//
// For this module only:
// This code is public domain. No change sufficient enough to constitute a
// significant or original work has been made, and thus it remains as such.
//
//
// DESCRIPTION:
//
// Implementation of POSIX opendir for Visual C++.
// Derived from the MinGW C Library Extensions Source (released to the
// public domain). As with other Win32 modules, don't include most DOOM
// headers into this or conflicts will occur.
//
// Original Header:
//
// * dirent.c
// * This file has no copyright assigned and is placed in the Public Domain.
// * This file is a part of the mingw-runtime package.
// * No warranty is given; refer to the file DISCLAIMER within the package.
// *
// * Derived from DIRLIB.C by Matt J. Weinstein
// * This note appears in the DIRLIB.H
// * DIRLIB.H by M. J. Weinstein Released to public domain 1-Jan-89
// *
// * Updated by Jeremy Bettis <jeremy@hksys.com>
// * Significantly revised and rewinddir, seekdir and telldir added by Colin
// * Peters <colin@fu.is.saga-u.ac.jp>
//
#ifndef _MSC_VER
#error i_opndir.c is for Microsoft Visual C++ only
#endif
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#define WIN32_LEAN_AND_MEAN
#include <windows.h> /* for GetFileAttributes */
#include <tchar.h>
#define SUFFIX _T("*")
#define SLASH _T("\\")
#include "win_opendir.h"
//
// opendir
//
// Returns a pointer to a DIR structure appropriately filled in to begin
// searching a directory.
//
DIR *opendir(const _TCHAR *szPath)
{
DIR *nd;
unsigned int rc;
_TCHAR szFullPath[MAX_PATH];
errno = 0;
if(!szPath)
{
errno = EFAULT;
return (DIR *)0;
}
if(szPath[0] == _T('\0'))
{
errno = ENOTDIR;
return (DIR *)0;
}
/* Attempt to determine if the given path really is a directory. */
rc = GetFileAttributes(szPath);
if(rc == (unsigned int)-1)
{
/* call GetLastError for more error info */
errno = ENOENT;
return (DIR *)0;
}
if(!(rc & FILE_ATTRIBUTE_DIRECTORY))
{
/* Error, entry exists but not a directory. */
errno = ENOTDIR;
return (DIR *)0;
}
/* Make an absolute pathname. */
_tfullpath(szFullPath, szPath, MAX_PATH);
/* Allocate enough space to store DIR structure and the complete
* directory path given. */
nd = (DIR *)(malloc(sizeof(DIR) + (_tcslen(szFullPath)
+ _tcslen(SLASH)
+ _tcslen(SUFFIX) + 1)
* sizeof(_TCHAR)));
if(!nd)
{
/* Error, out of memory. */
errno = ENOMEM;
return (DIR *)0;
}
/* Create the search expression. */
_tcscpy(nd->dd_name, szFullPath);
/* Add on a slash if the path does not end with one. */
if(nd->dd_name[0] != _T('\0')
&& _tcsrchr(nd->dd_name, _T('/')) != nd->dd_name
+ _tcslen(nd->dd_name) - 1
&& _tcsrchr(nd->dd_name, _T('\\')) != nd->dd_name
+ _tcslen(nd->dd_name) - 1)
{
_tcscat(nd->dd_name, SLASH);
}
/* Add on the search pattern */
_tcscat(nd->dd_name, SUFFIX);
/* Initialize handle to -1 so that a premature closedir doesn't try
* to call _findclose on it. */
nd->dd_handle = -1;
/* Initialize the status. */
nd->dd_stat = 0;
/* Initialize the dirent structure. ino and reclen are invalid under
* Win32, and name simply points at the appropriate part of the
* findfirst_t structure. */
nd->dd_dir.d_ino = 0;
nd->dd_dir.d_reclen = 0;
nd->dd_dir.d_namlen = 0;
memset(nd->dd_dir.d_name, 0, FILENAME_MAX);
return nd;
}
//
// readdir
//
// Return a pointer to a dirent structure filled with the information on the
// next entry in the directory.
//
struct dirent *readdir(DIR *dirp)
{
errno = 0;
/* Check for valid DIR struct. */
if(!dirp)
{
errno = EFAULT;
return (struct dirent *)0;
}
if (dirp->dd_stat < 0)
{
/* We have already returned all files in the directory
* (or the structure has an invalid dd_stat). */
return (struct dirent *)0;
}
else if (dirp->dd_stat == 0)
{
/* We haven't started the search yet. */
/* Start the search */
dirp->dd_handle = _tfindfirst(dirp->dd_name, &(dirp->dd_dta));
if(dirp->dd_handle == -1)
{
/* Whoops! Seems there are no files in that
* directory. */
dirp->dd_stat = -1;
}
else
{
dirp->dd_stat = 1;
}
}
else
{
/* Get the next search entry. */
if(_tfindnext(dirp->dd_handle, &(dirp->dd_dta)))
{
/* We are off the end or otherwise error.
_findnext sets errno to ENOENT if no more file
Undo this. */
DWORD winerr = GetLastError();
if(winerr == ERROR_NO_MORE_FILES)
errno = 0;
_findclose(dirp->dd_handle);
dirp->dd_handle = -1;
dirp->dd_stat = -1;
}
else
{
/* Update the status to indicate the correct
* number. */
dirp->dd_stat++;
}
}
if (dirp->dd_stat > 0)
{
/* Successfully got an entry. Everything about the file is
* already appropriately filled in except the length of the
* file name. */
dirp->dd_dir.d_namlen = _tcslen(dirp->dd_dta.name);
_tcscpy(dirp->dd_dir.d_name, dirp->dd_dta.name);
return &dirp->dd_dir;
}
return (struct dirent *)0;
}
//
// closedir
//
// Frees up resources allocated by opendir.
//
int closedir(DIR *dirp)
{
int rc;
errno = 0;
rc = 0;
if(!dirp)
{
errno = EFAULT;
return -1;
}
if(dirp->dd_handle != -1)
{
rc = _findclose(dirp->dd_handle);
}
/* Delete the dir structure. */
free(dirp);
return rc;
}
//
// rewinddir
//
// Return to the beginning of the directory "stream". We simply call findclose
// and then reset things like an opendir.
//
void rewinddir(DIR * dirp)
{
errno = 0;
if(!dirp)
{
errno = EFAULT;
return;
}
if(dirp->dd_handle != -1)
{
_findclose(dirp->dd_handle);
}
dirp->dd_handle = -1;
dirp->dd_stat = 0;
}
//
// telldir
//
// Returns the "position" in the "directory stream" which can be used with
// seekdir to go back to an old entry. We simply return the value in stat.
//
long telldir(DIR *dirp)
{
errno = 0;
if(!dirp)
{
errno = EFAULT;
return -1;
}
return dirp->dd_stat;
}
//
// seekdir
//
// Seek to an entry previously returned by telldir. We rewind the directory
// and call readdir repeatedly until either dd_stat is the position number
// or -1 (off the end). This is not perfect, in that the directory may
// have changed while we weren't looking. But that is probably the case with
// any such system.
//
void seekdir(DIR *dirp, long lPos)
{
errno = 0;
if(!dirp)
{
errno = EFAULT;
return;
}
if(lPos < -1)
{
/* Seeking to an invalid position. */
errno = EINVAL;
return;
}
else if(lPos == -1)
{
/* Seek past end. */
if(dirp->dd_handle != -1)
{
_findclose(dirp->dd_handle);
}
dirp->dd_handle = -1;
dirp->dd_stat = -1;
}
else
{
/* Rewind and read forward to the appropriate index. */
rewinddir(dirp);
while((dirp->dd_stat < lPos) && readdir(dirp))
; /* do-nothing loop */
}
}
// EOF