最近有一个任务要做WEBUI上管理SD卡的内容,至少要可以显示SD卡内容和下载。
先把任务分解,至少三点
1、显示SD卡内容
2、下载功能
3、与webs通信
再看最基本的第一点,显示SD卡内容,那么重点是对文件夹下的内容进行遍历查找。
通过查找资料认识了这两个函数:
DIR * opendir(const char * name);
opendir()用来打开参数name 指定的目录, 并返回DIR*形态的目录流, 和open()类似, 接下来对目录的读取和搜索都要使用此返回值.
struct dirent* readdir(DIR* dir_handle);
本函数用来读取目录。返回是dirent结构体指针
dirent结构体成员如下,
struct dirent { long d_ino; /* inode number 索引节点号 */ off_t d_off; /* offset to this dirent 在目录文件中的偏移 */ unsigned short d_reclen;/* length of this d_name 文件名长 */ unsigned char d_type; /* the type of d_name 文件类型 */ char d_name [NAME_MAX+1];/* file name (null-terminated) 文件名,最长255字符 */ }
在Linux下opendir()、readdir()和closedir()这三个函数主要用来遍历目录,注意不要忘了closedir()。在使用这三个函数前必须先包括以下两个头文件:
#include <sys/types.h>
#include <dirent.h>
了解以上这些,便可以写出简单函数测试了,网上找了一个函数简单修改:
#include <dirent.h> #include <sys/stat.h> char filename[256][256]; int len = 0; int trave_dir(char* path, int depth) { DIR *d; //声明一个句柄 struct dirent *file; //readdir函数的返回值就存放在这个结构体中 struct stat sb; if(!(d = opendir(path))) { printf("error opendir %s!!!\n",path); return -1; } while((file = readdir(d)) != NULL) { //把当前目录.,上一级目录..及隐藏文件都去掉,避免死循环遍历目录 if(strncmp(file->d_name, ".", 1) == 0) continue; strcpy(filename[len++], file->d_name); //保存遍历到的文件名 } closedir(d);//不要忘记了 return 0; } int main() { int depth = 1; int i; trave_dir("/media/card", depth); for(i = 0; i < len; i++) { printf("%s\t", filename[i]); } printf("\n"); return 0; }
原型是:
#include <stdio.h> #include <string.h> #include <sys/types.h> #include <dirent.h> #include <sys/stat.h> char filename[256][256]; int len = 0; int trave_dir(char* path, int depth) { DIR *d; /*声明一个句柄*/ struct dirent *file; /*readdir函数的返回值就存放在这个结构体中*/ struct stat sb; if(!(d = opendir(path))) { printf("error\n"); return -1; } while((file = readdir(d)) != NULL) { /*把当前目录.,上一级目录..及隐藏文件都去掉,避免死循环遍历目录*/ if(strncmp(file->d_name, ".", 1) == 0) continue; strcpy(filename[len++], file->d_name); /*保存遍历到的文件名*/ /*判断该文件是否是目录,及是否已搜索了三层,这里我定义只搜索了三层目录,太深就不搜了,省得搜出太多文件*/ if(stat(file->d_name, &sb) >= 0 && S_ISDIR(sb.st_mode) && depth <= 3) { trave_dir(file->d_name, depth + 1); } } closedir(d); return 0; } int main() { int depth = 1; int i; trave_dir("/home/user/", depth); for(i = 0; i < len; i++) { printf("%s\t", filename[i]); } printf("\n"); return 0; }
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以下内容转自:http://blog.csdn.net/wallwind/article/details/7528474,进行了简单的格式整理,未验证和研读代码
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1、linux C 遍历目录及其子目录:
#include <stdio.h> #include <string.h> #include <stdlib.h> #include <dirent.h> #include <sys/stat.h> #include <unistd.h> #include <sys/types.h> using namespace std; void listDir(char *path) { DIR *pDir ; struct dirent *ent ; int i=0 ; char childpath[512]; pDir=opendir(path); memset(childpath,0,sizeof(childpath)); while((ent=readdir(pDir))!=NULL) { if(ent->d_type & DT_DIR) { if(strcmp(ent->d_name,".")==0 || strcmp(ent->d_name,"..")==0) continue; sprintf(childpath,"%s/%s",path,ent->d_name); printf("path:%s/n",childpath); listDir(childpath); } else { cout<<ent->d_name<<endl; } } } int main(int argc,char *argv[]) { listDir(argv[1]); return 0; }
#include <stdio.h> #include <string.h> #include <sys/types.h> #include <dirent.h> #include <sys/stat.h> char filename[256][256]; int len = 0; int trave_dir(char* path, int depth) { DIR *d; //声明一个句柄 struct dirent *file; //readdir函数的返回值就存放在这个结构体中 struct stat sb; if(!(d = opendir(path))) { printf("error opendir %s!!!\n",path); return -1; } while((file = readdir(d)) != NULL) { //把当前目录.,上一级目录..及隐藏文件都去掉,避免死循环遍历目录 if(strncmp(file->d_name, ".", 1) == 0) continue; strcpy(filename[len++], file->d_name); //保存遍历到的文件名 //判断该文件是否是目录,及是否已搜索了三层,这里我定义只搜索了三层目录,太深就不搜了,省得搜出太多文件 if(stat(file->d_name, &sb) >= 0 && S_ISDIR(sb.st_mode) && depth <= 3) { trave_dir(file->d_name, depth + 1); } } closedir(d); return 0; } int main() { int depth = 1; int i; trave_dir("/usr/keygoe/ini/", depth); for(i = 0; i < len; i++) { printf("%s\t", filename[i]); } printf("\n"); return 0; }
#include <stdio.h> #include <dirent.h> #include <sys/stat.h> void List(char *path) { struct dirent* ent = NULL; DIR *pDir; pDir=opendir(path); while (NULL != (ent=readdir(pDir))) { if (ent->d_reclen==24) { if (ent->d_type==8) { printf("普通文件:%s\n", ent->d_name); } else { printf("子目录:%s\n",ent->d_name); List(ent->d_name); printf("返回%s\n",ent->d_name); } } } } int main(int argc, char *argv[]) { List(argv[1]); return 0; }
void List(char *path) { printf("路径为[%s]\n", path); struct dirent* ent = NULL; DIR *pDir; pDir=opendir(path); //d_reclen:16表示子目录或以.开头的隐藏文件,24表示普通文本文件,28为二进制文件,还有其他…… while (NULL != (ent=readdir(pDir))) { printf("reclen=%d type=%d\t", ent->d_reclen, ent->d_type); if (ent->d_reclen==24) { //d_type:4表示为目录,8表示为文件 if (ent->d_type==8) { printf("普通文件[%s]\n", ent->d_name); } } else if(ent->d_reclen==16) { printf("[.]开头的子目录或隐藏文件[%s]\n",ent->d_name); } else { printf("其他文件[%s]\n", ent->d_name); } } }
#include <stdio.h> #include <dirent.h> #include <sys/types.h> #include <sys/stat.h> void dir_scan(char *path, char *file); int count = 0; int main(int argc, char *argv[]) { struct stat s; if(argc != 2){ printf("one direction requried\n"); exit(1); } if(lstat(argv[1], &s) < 0){ printf("lstat error\n"); exit(2); } //判断一个路径是否是目录 if(!S_ISDIR(s.st_mode)){ printf("%s is not a direction name\n", argv[1]); exit(3); } dir_scan("", argv[1]); printf("total: %d files\n", count); exit(0); } void dir_scan(char *path, char *file) { struct stat s; DIR *dir; struct dirent *dt; char dirname[50]; memset(dirname, 0, 50*sizeof(char)); strcpy(dirname, path); if(lstat(file, &s) < 0){ printf("lstat error\n"); } if(S_ISDIR(s.st_mode)){ strcpy(dirname+strlen(dirname), file); strcpy(dirname+strlen(dirname), "/"); if((dir = opendir(file)) == NULL){ printf("opendir %s/%s error\n"); exit(4); } if(chdir(file) < 0) { printf("chdir error\n"); exit(5); } while((dt = readdir(dir)) != NULL){ if(dt->d_name[0] == '.'){ continue; } dir_scan(dirname, dt->d_name); } if(chdir("..") < 0){ printf("chdir error\n"); exit(6); } }else{ printf("%s%s\n", dirname, file); count++; } }
int main(int argc, char **argv) { DIR * pdir; struct dirent * pdirent; struct stat f_ftime; int fcnt;/*文件数目统计*/ pdir=opendir("./"); if(pdir==NULL) { return(-1); } fcnt=0; for(pdirent=readdir(pdir);pdirent!=NULL;pdirent=readdir(pdir)) { if(strcmp(pdirent->d_name,".")==0||strcmp(pdirent->d_name,"..")==0) continue; if(stat(pdirent->d_name,&f_ftime)!=0) return -1 ; if(S_ISDIR(f_ftime.st_mode)) continue; /*子目录跳过*/ fcnt++; printf("文件:%s\n",pdirent->d_name); } printf("文件总数%d\n",fcnt); closedir(pdir); return 0; }
#include <unistd.h> #include <stdio.h> #include <dirent.h> #include <string.h> #include <sys/stat.h> void printdir(char *dir, int depth) { DIR *dp; struct dirent *entry; struct stat statbuf; if((dp = opendir(dir)) == NULL) { fprintf(stderr, "cannot open directory: %s\n ", dir); return; } chdir(dir); while((entry = readdir(dp)) != NULL) { lstat(entry-> d_name,&statbuf); if(S_ISDIR(statbuf.st_mode)) { /**//* Found a directory, but ignore . and .. */ if(strcmp( ". ",entry-> d_name) == 0 || strcmp( ".. ",entry-> d_name) == 0) continue; printf( "%*s%s/\n ",depth, " ",entry-> d_name); /**//* Recurse at a new indent level */ printdir(entry-> d_name,depth+4); } else printf( "%*s%s\n ",depth, " ",entry-> d_name); } chdir( ".. "); closedir(dp); } /**//* Now we move onto the main function. */ int main(int argc, char* argv[]) { char *topdir, pwd[2]= ". "; if (argc != 2) topdir=pwd; else topdir=argv[1]; printf( "Directory scan of %s\n ",topdir); printdir(topdir,0); printf( "done.\n "); exit(0); }