libcurl 庫的ftp上傳和下載代碼

#include <stdlib.h>  
    #include <stdio.h>  
    #include <curl/curl.h>  
    #include <sys/stat.h>  
    /* parse headers for Content-Length */  
    size_t getcontentlengthfunc(void *ptr, size_t size, size_t nmemb, void *stream)   
    {  
        int r;  
        long len = 0;  
        /* _snscanf() is Win32 specific */  
        //r = _snscanf(ptr, size * nmemb, "Content-Length: %ld\n", &len);  
        r = sscanf((const char*)ptr, "Content-Length: %ld\n", &len);  
        if (r) /* Microsoft: we don't read the specs */  
            *((long *) stream) = len;  
        return size * nmemb;  
    }  
    /* discard downloaded data */  
    size_t discardfunc(void *ptr, size_t size, size_t nmemb, void *stream)   
    {  
        return size * nmemb;  
    }  
    //write data to upload  
    size_t writefunc(void *ptr, size_t size, size_t nmemb, void *stream)  
    {  
        return fwrite(ptr, size, nmemb, (FILE*)stream);  
    }  
    /* read data to upload */  
    size_t readfunc(void *ptr, size_t size, size_t nmemb, void *stream)  
    {  
        FILE *f = (FILE*)stream;  
        size_t n;  
        if (ferror(f))  
            return CURL_READFUNC_ABORT;  
        n = fread(ptr, size, nmemb, f) * size;  
        return n;  
    }  
    int upload(CURL *curlhandle, const char * remotepath, const char * localpath, long timeout, long tries)  
    {  
        FILE *f;  
        long uploaded_len = 0;  
        CURLcode r = CURLE_GOT_NOTHING;  
        int c;  
        f = fopen(localpath, "rb");  
        if (f == NULL) {  
            perror(NULL);  
            return 0;  
        }  
        curl_easy_setopt(curlhandle, CURLOPT_UPLOAD, 1L);  
        curl_easy_setopt(curlhandle, CURLOPT_URL, remotepath);  
        curl_easy_setopt(curlhandle, CURLOPT_USERPWD, "spider:spider");     
        if (timeout)  
            curl_easy_setopt(curlhandle, CURLOPT_FTP_RESPONSE_TIMEOUT, timeout);  
        curl_easy_setopt(curlhandle, CURLOPT_HEADERFUNCTION, getcontentlengthfunc);  
        curl_easy_setopt(curlhandle, CURLOPT_HEADERDATA, &uploaded_len);  
        curl_easy_setopt(curlhandle, CURLOPT_WRITEFUNCTION, discardfunc);  
        curl_easy_setopt(curlhandle, CURLOPT_READFUNCTION, readfunc);  
        curl_easy_setopt(curlhandle, CURLOPT_READDATA, f);  
        curl_easy_setopt(curlhandle, CURLOPT_FTPPORT, "-"); /* disable passive mode */  
        curl_easy_setopt(curlhandle, CURLOPT_FTP_CREATE_MISSING_DIRS, 1L);  
        curl_easy_setopt(curlhandle, CURLOPT_VERBOSE, 1L);  
        for (c = 0; (r != CURLE_OK) && (c < tries); c++) {  
            /* are we resuming? */  
            if (c) { /* yes */  
                /* determine the length of the file already written */  
                /* 
                * With NOBODY and NOHEADER, libcurl will issue a SIZE 
                * command, but the only way to retrieve the result is 
                * to parse the returned Content-Length header. Thus, 
                * getcontentlengthfunc(). We need discardfunc() above 
                * because HEADER will dump the headers to stdout 
                * without it. 
                */  
                curl_easy_setopt(curlhandle, CURLOPT_NOBODY, 1L);  
                curl_easy_setopt(curlhandle, CURLOPT_HEADER, 1L);  
                r = curl_easy_perform(curlhandle);  
                if (r != CURLE_OK)  
                    continue;  
                curl_easy_setopt(curlhandle, CURLOPT_NOBODY, 0L);  
                curl_easy_setopt(curlhandle, CURLOPT_HEADER, 0L);  
                fseek(f, uploaded_len, SEEK_SET);  
                curl_easy_setopt(curlhandle, CURLOPT_APPEND, 1L);  
            }  
            else { /* no */  
                curl_easy_setopt(curlhandle, CURLOPT_APPEND, 0L);  
            }  
            r = curl_easy_perform(curlhandle);  
        }  
        fclose(f);  
        if (r == CURLE_OK)  
            return 1;  
        else {  
            fprintf(stderr, "%s\n", curl_easy_strerror(r));  
            return 0;  
        }  
    }  
    // 下載  
    int download(CURL *curlhandle, const char * remotepath, const char * localpath, long timeout, long tries)  
    {  
        FILE *f;  
        curl_off_t local_file_len = -1 ;  
        long filesize =0 ;  
        CURLcode r = CURLE_GOT_NOTHING;  
        struct stat file_info;  
        int use_resume = 0;  
        //獲取本地文件大小信息  
        if(stat(localpath, &file_info) == 0)  
        {  
            local_file_len = file_info.st_size;   
            use_resume = 1;  
        }  
        //追加方式打開文件，實現斷點續傳  
        f = fopen(localpath, "ab+");  
        if (f == NULL) {  
            perror(NULL);  
            return 0;  
        }  
        curl_easy_setopt(curlhandle, CURLOPT_URL, remotepath);  
        curl_easy_setopt(curlhandle, CURLOPT_USERPWD, "spider:spider");     
        //鏈接超時設置  
        curl_easy_setopt(curlhandle, CURLOPT_CONNECTTIMEOUT, timeout);  
        //設置頭處理函數  
        curl_easy_setopt(curlhandle, CURLOPT_HEADERFUNCTION, getcontentlengthfunc);  
        curl_easy_setopt(curlhandle, CURLOPT_HEADERDATA, &filesize);  
        // 設置斷點續傳  
        curl_easy_setopt(curlhandle, CURLOPT_RESUME_FROM_LARGE, use_resume?local_file_len:0);  
        curl_easy_setopt(curlhandle, CURLOPT_WRITEFUNCTION, writefunc);  
        curl_easy_setopt(curlhandle, CURLOPT_WRITEDATA, f);  
        curl_easy_setopt(curlhandle, CURLOPT_NOPROGRESS, 1L);  
        curl_easy_setopt(curlhandle, CURLOPT_VERBOSE, 1L);  
        r = curl_easy_perform(curlhandle);  
        fclose(f);  
        if (r == CURLE_OK)  
            return 1;  
        else {  
            fprintf(stderr, "%s\n", curl_easy_strerror(r));  
            return 0;  
        }  
    }  
    int main(int c, char **argv)   
    {  
        CURL *curlhandle = NULL;  
        CURL *curldwn = NULL;  
        curl_global_init(CURL_GLOBAL_ALL);  
        curlhandle = curl_easy_init();  
        curldwn = curl_easy_init();  
        upload(curlhandle, "ftp://192.168.0.185/a/success", "D:/abc.jpg", 1, 3);  
        download(curldwn, "ftp://192.168.0.185/a/success", "D:/abc1.jpg", 1, 3);  
        curl_easy_cleanup(curlhandle);  
        curl_easy_cleanup(curldwn);  
        curl_global_cleanup();  
        return 0;  
    }