windows客户端开发–文件以及文件夹相关操作(windows api)
一文中，主要使用了一些windows api实现文件以及文件夹的相关操作。
c++语言本身不提供文件相关操作，我们也可以使用boost库完成我们想要的功能。
但是为了仅仅一个小功能，引入boost库，似乎有点小题大做吧，那今天就介绍一种“跨平台”的文件操作，dirent。
这里所谓的“跨平台”其实是个伪命题，不是真正意义上的。
let us go!!!
初识dirent
是POSIX.1标准定义的unix类目录操作的头文件，包含了许多UNIX系统服务的函数原型，例如opendir函数、readdir函数.
看到上面的描述，你会理解我所说的用引号引起来的“跨平台”了。
在windows平台上同样可以使用：
https://github.com/tronkko/dirent/blob/master/include/dirent.h
只是简单的包含这个头文件dirent.h就可以了，因为这个文件只有八百多行，在博客的最后面，我将会贴上这个源码。
熟悉dirent
dirent结构体：
struct dirent {
long d_ino; /* Always zero */
unsigned short d_reclen; /* Structure size */
size_t d_namlen; /* Length of name without \0 */
int d_type; /* File type */
char d_name[PATH_MAX]; /* File name */
};
typedef struct dirent dirent;
DIR：
A type representing a directory stream.
struct DIR {
struct dirent ent;
struct _WDIR *wdirp;
};
typedef struct DIR DIR;
一些函数：
int closedir(DIR *);
DIR *opendir(const char *);
struct dirent *readdir(DIR *);
int readdir_r(DIR *, struct dirent *, struct dirent **);
void rewinddir(DIR *);
void seekdir(DIR *, long int);
long int telldir(DIR *);
使用dirent
删除文件夹下所有文件：
DIR *foder = opendir(file_path_to_delete.c_str());
struct dirent *next_file;
char filepath[256];
while ((next_file = readdir(foder)) != NULL)
{
// build the path for each file in the folder
sprintf(filepath, "%s/%s", course_path.c_str(), next_file->d_name);
remove(filepath);
}
注意：
路径要以’/’结尾：
file_path_to_delete += "\/";
判断目录是否存在：
DIR *mydir = NULL;
if((mydir= opendir(dir))==NULL)//判断目录
{
int ret = mkdir(dir, MODE);//创建目录
if (ret != 0)
{
return -1;
}
printf("%s created sucess!/n", dir);
} 判断是文件夹还是文件：
unsigned char isFile =0x8;
DIR Dir;
struct dirent *DirEntry;
Dir = opendir("c:/test/")
while(Dir=readdir(Dir))
{
if ( DirEntry->d_type == isFile)
{
cout <<"Found a File : " << DirEntry->d_name << endl;
}
}==========================================================华丽的分割线============================================================
//dirent.h
/*
* dirent.h - dirent API for Microsoft Visual Studio
*
* Copyright (C) 2006-2012 Toni Ronkko
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* ``Software''), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED ``AS IS'', WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL TONI RONKKO BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*
* $Id: dirent.h,v 1.20 2014/03/19 17:52:23 tronkko Exp $
*/
#ifndef DIRENT_H
#define DIRENT_H
/*
* Define architecture flags so we don't need to include windows.h.
* Avoiding windows.h makes it simpler to use windows sockets in conjunction
* with dirent.h.
*/
#if !defined(_68K_) && !defined(_MPPC_) && !defined(_X86_) && !defined(_IA64_) && !defined(_AMD64_) && defined(_M_IX86)
# define _X86_
#endif
#if !defined(_68K_) && !defined(_MPPC_) && !defined(_X86_) && !defined(_IA64_) && !defined(_AMD64_) && defined(_M_AMD64)
#define _AMD64_
#endif
#include <stdio.h>
#include <stdarg.h>
#include <windef.h>
#include <winbase.h>
#include <wchar.h>
#include <string.h>
#include <stdlib.h>
#include <malloc.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
/* Indicates that d_type field is available in dirent structure */
#define _DIRENT_HAVE_D_TYPE
/* Indicates that d_namlen field is available in dirent structure */
#define _DIRENT_HAVE_D_NAMLEN
/* Entries missing from MSVC 6.0 */
#if !defined(FILE_ATTRIBUTE_DEVICE)
# define FILE_ATTRIBUTE_DEVICE 0x40
#endif
/* File type and permission flags for stat() */
#if !defined(S_IFMT)
# define S_IFMT _S_IFMT /* File type mask */
#endif
#if !defined(S_IFDIR)
# define S_IFDIR _S_IFDIR /* Directory */
#endif
#if !defined(S_IFCHR)
# define S_IFCHR _S_IFCHR /* Character device */
#endif
#if !defined(S_IFFIFO)
# define S_IFFIFO _S_IFFIFO /* Pipe */
#endif
#if !defined(S_IFREG)
# define S_IFREG _S_IFREG /* Regular file */
#endif
#if !defined(S_IREAD)
# define S_IREAD _S_IREAD /* Read permission */
#endif
#if !defined(S_IWRITE)
# define S_IWRITE _S_IWRITE /* Write permission */
#endif
#if !defined(S_IEXEC)
# define S_IEXEC _S_IEXEC /* Execute permission */
#endif
#if !defined(S_IFIFO)
# define S_IFIFO _S_IFIFO /* Pipe */
#endif
#if !defined(S_IFBLK)
# define S_IFBLK 0 /* Block device */
#endif
#if !defined(S_IFLNK)
# define S_IFLNK 0 /* Link */
#endif
#if !defined(S_IFSOCK)
# define S_IFSOCK 0 /* Socket */
#endif
#if defined(_MSC_VER)
# define S_IRUSR S_IREAD /* Read user */
# define S_IWUSR S_IWRITE /* Write user */
# define S_IXUSR 0 /* Execute user */
# define S_IRGRP 0 /* Read group */
# define S_IWGRP 0 /* Write group */
# define S_IXGRP 0 /* Execute group */
# define S_IROTH 0 /* Read others */
# define S_IWOTH 0 /* Write others */
# define S_IXOTH 0 /* Execute others */
#endif
/* Maximum length of file name */
#if !defined(PATH_MAX)
# define PATH_MAX MAX_PATH
#endif
#if !defined(FILENAME_MAX)
# define FILENAME_MAX MAX_PATH
#endif
#if !defined(NAME_MAX)
# define NAME_MAX FILENAME_MAX
#endif
/* File type flags for d_type */
#define DT_UNKNOWN 0
#define DT_REG S_IFREG
#define DT_DIR S_IFDIR
#define DT_FIFO S_IFIFO
#define DT_SOCK S_IFSOCK
#define DT_CHR S_IFCHR
#define DT_BLK S_IFBLK
#define DT_LNK S_IFLNK
/* Macros for converting between st_mode and d_type */
#define IFTODT(mode) ((mode) & S_IFMT)
#define DTTOIF(type) (type)
/*
* File type macros. Note that block devices, sockets and links cannot be
* distinguished on Windows and the macros S_ISBLK, S_ISSOCK and S_ISLNK are
* only defined for compatibility. These macros should always return false
* on Windows.
*/
#define S_ISFIFO(mode) (((mode) & S_IFMT) == S_IFIFO)
#define S_ISDIR(mode) (((mode) & S_IFMT) == S_IFDIR)
#define S_ISREG(mode) (((mode) & S_IFMT) == S_IFREG)
#define S_ISLNK(mode) (((mode) & S_IFMT) == S_IFLNK)
#define S_ISSOCK(mode) (((mode) & S_IFMT) == S_IFSOCK)
#define S_ISCHR(mode) (((mode) & S_IFMT) == S_IFCHR)
#define S_ISBLK(mode) (((mode) & S_IFMT) == S_IFBLK)
/* Return the exact length of d_namlen without zero terminator */
#define _D_EXACT_NAMLEN(p) ((p)->d_namlen)
/* Return number of bytes needed to store d_namlen */
#define _D_ALLOC_NAMLEN(p) (PATH_MAX)
#ifdef __cplusplus
extern "C" {
#endif
/* Wide-character version */
struct _wdirent {
long d_ino; /* Always zero */
unsigned short d_reclen; /* Structure size */
size_t d_namlen; /* Length of name without \0 */
int d_type; /* File type */
wchar_t d_name[PATH_MAX]; /* File name */
};
typedef struct _wdirent _wdirent;
struct _WDIR {
struct _wdirent ent; /* Current directory entry */
WIN32_FIND_DATAW data; /* Private file data */
int cached; /* True if data is valid */
HANDLE handle; /* Win32 search handle */
wchar_t *patt; /* Initial directory name */
};
typedef struct _WDIR _WDIR;
static _WDIR *_wopendir(const wchar_t *dirname);
static struct _wdirent *_wreaddir(_WDIR *dirp);
static int _wclosedir(_WDIR *dirp);
static void _wrewinddir(_WDIR* dirp);
/* For compatibility with Symbian */
#define wdirent _wdirent
#define WDIR _WDIR
#define wopendir _wopendir
#define wreaddir _wreaddir
#define wclosedir _wclosedir
#define wrewinddir _wrewinddir
/* Multi-byte character versions */
struct dirent {
long d_ino; /* Always zero */
unsigned short d_reclen; /* Structure size */
size_t d_namlen; /* Length of name without \0 */
int d_type; /* File type */
char d_name[PATH_MAX]; /* File name */
};
typedef struct dirent dirent;
struct DIR {
struct dirent ent;
struct _WDIR *wdirp;
};
typedef struct DIR DIR;
static DIR *opendir(const char *dirname);
static struct dirent *readdir(DIR *dirp);
static int closedir(DIR *dirp);
static void rewinddir(DIR* dirp);
/* Internal utility functions */
static WIN32_FIND_DATAW *dirent_first(_WDIR *dirp);
static WIN32_FIND_DATAW *dirent_next(_WDIR *dirp);
static int dirent_mbstowcs_s(
size_t *pReturnValue,
wchar_t *wcstr,
size_t sizeInWords,
const char *mbstr,
size_t count);
static int dirent_wcstombs_s(
size_t *pReturnValue,
char *mbstr,
size_t sizeInBytes,
const wchar_t *wcstr,
size_t count);
static void dirent_set_errno(int error);
/*
* Open directory stream DIRNAME for read and return a pointer to the
* internal working area that is used to retrieve individual directory
* entries.
*/
static _WDIR*
_wopendir(
const wchar_t *dirname)
{
_WDIR *dirp = NULL;
int error;
/* Must have directory name */
if (dirname == NULL || dirname[0] == '\0') {
dirent_set_errno(ENOENT);
return NULL;
}
/* Allocate new _WDIR structure */
dirp = (_WDIR*)malloc(sizeof(struct _WDIR));
if (dirp != NULL) {
DWORD n;
/* Reset _WDIR structure */
dirp->handle = INVALID_HANDLE_VALUE;
dirp->patt = NULL;
dirp->cached = 0;
/* Compute the length of full path plus zero terminator */
n = GetFullPathNameW(dirname, 0, NULL, NULL);
/* Allocate room for absolute directory name and search pattern */
dirp->patt = (wchar_t*)malloc(sizeof(wchar_t) * n + 16);
if (dirp->patt) {
/*
* Convert relative directory name to an absolute one. This
* allows rewinddir() to function correctly even when current
* working directory is changed between opendir() and rewinddir().
*/
n = GetFullPathNameW(dirname, n, dirp->patt, NULL);
if (n > 0) {
wchar_t *p;
/* Append search pattern \* to the directory name */
p = dirp->patt + n;
if (dirp->patt < p) {
switch (p[-1]) {
case '\\':
case '/':
case ':':
/* Directory ends in path separator, e.g. c:\temp\ */
/*NOP*/;
break;
default:
/* Directory name doesn't end in path separator */
*p++ = '\\';
}
}
*p++ = '*';
*p = '\0';
/* Open directory stream and retrieve the first entry */
if (dirent_first(dirp)) {
/* Directory stream opened successfully */
error = 0;
}
else {
/* Cannot retrieve first entry */
error = 1;
dirent_set_errno(ENOENT);
}
}
else {
/* Cannot retrieve full path name */
dirent_set_errno(ENOENT);
error = 1;
}
}
else {
/* Cannot allocate memory for search pattern */
error = 1;
}
}
else {
/* Cannot allocate _WDIR structure */
error = 1;
}
/* Clean up in case of error */
if (error && dirp) {
_wclosedir(dirp);
dirp = NULL;
}
return dirp;
}
/*
* Read next directory entry. The directory entry is returned in dirent
* structure in the d_name field. Individual directory entries returned by
* this function include regular files, sub-directories, pseudo-directories
* "." and ".." as well as volume labels, hidden files and system files.
*/
static struct _wdirent*
_wreaddir(
_WDIR *dirp)
{
WIN32_FIND_DATAW *datap;
struct _wdirent *entp;
/* Read next directory entry */
datap = dirent_next(dirp);
if (datap) {
size_t n;
DWORD attr;
/* Pointer to directory entry to return */
entp = &dirp->ent;
/*
* Copy file name as wide-character string. If the file name is too
* long to fit in to the destination buffer, then truncate file name
* to PATH_MAX characters and zero-terminate the buffer.
*/
n = 0;
while (n + 1 < PATH_MAX && datap->cFileName[n] != 0) {
entp->d_name[n] = datap->cFileName[n];
n++;
}
dirp->ent.d_name[n] = 0;
/* Length of file name excluding zero terminator */
entp->d_namlen = n;
/* File type */
attr = datap->dwFileAttributes;
if ((attr & FILE_ATTRIBUTE_DEVICE) != 0) {
entp->d_type = DT_CHR;
}
else if ((attr & FILE_ATTRIBUTE_DIRECTORY) != 0) {
entp->d_type = DT_DIR;
}
else {
entp->d_type = DT_REG;
}
/* Reset dummy fields */
entp->d_ino = 0;
entp->d_reclen = sizeof(struct _wdirent);
}
else {
/* Last directory entry read */
entp = NULL;
}
return entp;
}
/*
* Close directory stream opened by opendir() function. This invalidates the
* DIR structure as well as any directory entry read previously by
* _wreaddir().
*/
static int
_wclosedir(
_WDIR *dirp)
{
int ok;
if (dirp) {
/* Release search handle */
if (dirp->handle != INVALID_HANDLE_VALUE) {
FindClose(dirp->handle);
dirp->handle = INVALID_HANDLE_VALUE;
}
/* Release search pattern */
if (dirp->patt) {
free(dirp->patt);
dirp->patt = NULL;
}
/* Release directory structure */
free(dirp);
ok = /*success*/0;
}
else {
/* Invalid directory stream */
dirent_set_errno(EBADF);
ok = /*failure*/-1;
}
return ok;
}
/*
* Rewind directory stream such that _wreaddir() returns the very first
* file name again.
*/
static void
_wrewinddir(
_WDIR* dirp)
{
if (dirp) {
/* Release existing search handle */
if (dirp->handle != INVALID_HANDLE_VALUE) {
FindClose(dirp->handle);
}
/* Open new search handle */
dirent_first(dirp);
}
}
/* Get first directory entry (internal) */
static WIN32_FIND_DATAW*
dirent_first(
_WDIR *dirp)
{
WIN32_FIND_DATAW *datap;
/* Open directory and retrieve the first entry */
dirp->handle = FindFirstFileW(dirp->patt, &dirp->data);
if (dirp->handle != INVALID_HANDLE_VALUE) {
/* a directory entry is now waiting in memory */
datap = &dirp->data;
dirp->cached = 1;
}
else {
/* Failed to re-open directory: no directory entry in memory */
dirp->cached = 0;
datap = NULL;
}
return datap;
}
/* Get next directory entry (internal) */
static WIN32_FIND_DATAW*
dirent_next(
_WDIR *dirp)
{
WIN32_FIND_DATAW *p;
/* Get next directory entry */
if (dirp->cached != 0) {
/* A valid directory entry already in memory */
p = &dirp->data;
dirp->cached = 0;
}
else if (dirp->handle != INVALID_HANDLE_VALUE) {
/* Get the next directory entry from stream */
if (FindNextFileW(dirp->handle, &dirp->data) != FALSE) {
/* Got a file */
p = &dirp->data;
}
else {
/* The very last entry has been processed or an error occured */
FindClose(dirp->handle);
dirp->handle = INVALID_HANDLE_VALUE;
p = NULL;
}
}
else {
/* End of directory stream reached */
p = NULL;
}
return p;
}
/*
* Open directory stream using plain old C-string.
*/
static DIR*
opendir(
const char *dirname)
{
struct DIR *dirp;
int error;
/* Must have directory name */
if (dirname == NULL || dirname[0] == '\0') {
dirent_set_errno(ENOENT);
return NULL;
}
/* Allocate memory for DIR structure */
dirp = (DIR*)malloc(sizeof(struct DIR));
if (dirp) {
wchar_t wname[PATH_MAX];
size_t n;
/* Convert directory name to wide-character string */
error = dirent_mbstowcs_s(&n, wname, PATH_MAX, dirname, PATH_MAX);
if (!error) {
/* Open directory stream using wide-character name */
dirp->wdirp = _wopendir(wname);
if (dirp->wdirp) {
/* Directory stream opened */
error = 0;
}
else {
/* Failed to open directory stream */
error = 1;
}
}
else {
/*
* Cannot convert file name to wide-character string. This
* occurs if the string contains invalid multi-byte sequences or
* the output buffer is too small to contain the resulting
* string.
*/
error = 1;
}
}
else {
/* Cannot allocate DIR structure */
error = 1;
}
/* Clean up in case of error */
if (error && dirp) {
free(dirp);
dirp = NULL;
}
return dirp;
}
/*
* Read next directory entry.
*
* When working with text consoles, please note that file names returned by
* readdir() are represented in the default ANSI code page while any output to
* console is typically formatted on another code page. Thus, non-ASCII
* characters in file names will not usually display correctly on console. The
* problem can be fixed in two ways: (1) change the character set of console
* to 1252 using chcp utility and use Lucida Console font, or (2) use
* _cprintf function when writing to console. The _cprinf() will re-encode
* ANSI strings to the console code page so many non-ASCII characters will
* display correcly.
*/
static struct dirent*
readdir(
DIR *dirp)
{
WIN32_FIND_DATAW *datap;
struct dirent *entp;
/* Read next directory entry */
datap = dirent_next(dirp->wdirp);
if (datap) {
size_t n;
int error;
/* Attempt to convert file name to multi-byte string */
error = dirent_wcstombs_s(
&n, dirp->ent.d_name, PATH_MAX, datap->cFileName, PATH_MAX);
/*
* If the file name cannot be represented by a multi-byte string,
* then attempt to use old 8+3 file name. This allows traditional
* Unix-code to access some file names despite of unicode
* characters, although file names may seem unfamiliar to the user.
*
* Be ware that the code below cannot come up with a short file
* name unless the file system provides one. At least
* VirtualBox shared folders fail to do this.
*/
if (error && datap->cAlternateFileName[0] != '\0') {
error = dirent_wcstombs_s(
&n, dirp->ent.d_name, PATH_MAX,
datap->cAlternateFileName, PATH_MAX);
}
if (!error) {
DWORD attr;
/* Initialize directory entry for return */
entp = &dirp->ent;
/* Length of file name excluding zero terminator */
entp->d_namlen = n - 1;
/* File attributes */
attr = datap->dwFileAttributes;
if ((attr & FILE_ATTRIBUTE_DEVICE) != 0) {
entp->d_type = DT_CHR;
}
else if ((attr & FILE_ATTRIBUTE_DIRECTORY) != 0) {
entp->d_type = DT_DIR;
}
else {
entp->d_type = DT_REG;
}
/* Reset dummy fields */
entp->d_ino = 0;
entp->d_reclen = sizeof(struct dirent);
}
else {
/*
* Cannot convert file name to multi-byte string so construct
* an errornous directory entry and return that. Note that
* we cannot return NULL as that would stop the processing
* of directory entries completely.
*/
entp = &dirp->ent;
entp->d_name[0] = '?';
entp->d_name[1] = '\0';
entp->d_namlen = 1;
entp->d_type = DT_UNKNOWN;
entp->d_ino = 0;
entp->d_reclen = 0;
}
}
else {
/* No more directory entries */
entp = NULL;
}
return entp;
}
/*
* Close directory stream.
*/
static int
closedir(
DIR *dirp)
{
int ok;
if (dirp) {
/* Close wide-character directory stream */
ok = _wclosedir(dirp->wdirp);
dirp->wdirp = NULL;
/* Release multi-byte character version */
free(dirp);
}
else {
/* Invalid directory stream */
dirent_set_errno(EBADF);
ok = /*failure*/-1;
}
return ok;
}
/*
* Rewind directory stream to beginning.
*/
static void
rewinddir(
DIR* dirp)
{
/* Rewind wide-character string directory stream */
_wrewinddir(dirp->wdirp);
}
/* Convert multi-byte string to wide character string */
static int
dirent_mbstowcs_s(
size_t *pReturnValue,
wchar_t *wcstr,
size_t sizeInWords,
const char *mbstr,
size_t count)
{
int error;
#if defined(_MSC_VER) && _MSC_VER >= 1400
/* Microsoft Visual Studio 2005 or later */
error = mbstowcs_s(pReturnValue, wcstr, sizeInWords, mbstr, count);
#else
/* Older Visual Studio or non-Microsoft compiler */
size_t n;
/* Convert to wide-character string (or count characters) */
n = mbstowcs(wcstr, mbstr, sizeInWords);
if (!wcstr || n < count) {
/* Zero-terminate output buffer */
if (wcstr && sizeInWords) {
if (n >= sizeInWords) {
n = sizeInWords - 1;
}
wcstr[n] = 0;
}
/* Length of resuting multi-byte string WITH zero terminator */
if (pReturnValue) {
*pReturnValue = n + 1;
}
/* Success */
error = 0;
}
else {
/* Could not convert string */
error = 1;
}
#endif
return error;
}
/* Convert wide-character string to multi-byte string */
static int
dirent_wcstombs_s(
size_t *pReturnValue,
char *mbstr,
size_t sizeInBytes, /* max size of mbstr */
const wchar_t *wcstr,
size_t count)
{
int error;
#if defined(_MSC_VER) && _MSC_VER >= 1400
/* Microsoft Visual Studio 2005 or later */
error = wcstombs_s(pReturnValue, mbstr, sizeInBytes, wcstr, count);
#else
/* Older Visual Studio or non-Microsoft compiler */
size_t n;
/* Convert to multi-byte string (or count the number of bytes needed) */
n = wcstombs(mbstr, wcstr, sizeInBytes);
if (!mbstr || n < count) {
/* Zero-terminate output buffer */
if (mbstr && sizeInBytes) {
if (n >= sizeInBytes) {
n = sizeInBytes - 1;
}
mbstr[n] = '\0';
}
/* Lenght of resulting multi-bytes string WITH zero-terminator */
if (pReturnValue) {
*pReturnValue = n + 1;
}
/* Success */
error = 0;
}
else {
/* Cannot convert string */
error = 1;
}
#endif
return error;
}
/* Set errno variable */
static void
dirent_set_errno(
int error)
{
#if defined(_MSC_VER) && _MSC_VER >= 1400
/* Microsoft Visual Studio 2005 and later */
_set_errno(error);
#else
/* Non-Microsoft compiler or older Microsoft compiler */
errno = error;
#endif
}
#ifdef __cplusplus
}
#endif
#endif /*DIRENT_H*/
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