curl多线程下载实现

其实libcurl自带一个应用，很高大上，但是作为范例参考怎么使用libcurl觉得不大适合！还是写一些helloworl的程序的，一目了然......

#include "stdafx.h"
#include <io.h>
#include "curl/curl.h"
#include <string>
 
#include "curl/easy.h"
 
#include "pthread.h"
 
using namespace std;
 
struct tNode 
{
	FILE *fp;
	int startidx;
	int maxidx;
	void *_curl;
	pthread_t _tid;
};
bool bError = false;
int threadCnt = 0;
static pthread_mutex_t foo_mutex = PTHREAD_MUTEX_INITIALIZER;
static size_t downLoadPackage(void *ptr, size_t size, size_t nmemb, void *userdata)
{
	tNode *node = (tNode*)userdata;
	size_t written = 0;
	pthread_mutex_lock(&foo_mutex);
	if ( node->startidx + size * nmemb <= node->maxidx )
	{
		fseek( node->fp, node->startidx, SEEK_SET );
		written = fwrite(ptr, size, nmemb, node->fp);
		node->startidx += size * nmemb;
	}
	else
	{
		fseek( node->fp, node->startidx, SEEK_SET );
		written = fwrite(ptr, 1, node->maxidx - node->startidx + 1, node->fp);
		node->startidx = node->maxidx;
	}
	pthread_mutex_unlock(&foo_mutex);
	return written;
}
 
int assetsManagerProgressFunc(void *ptr, double totalToDownload, double nowDownloaded, double totalToUpLoad, double nowUpLoaded)
{
	static int percent = 0;
	int tmp = 0;
	if ( totalToDownload > 0 )
	{
		tmp = (int)(nowDownloaded / totalToDownload * 100);
	}
	
	printf("下载进度%0d%%\r", tmp);
	return 0;
}
 
/************************************************************************/
/* 获取要下载的远程文件的大小 											*/
/************************************************************************/
long getDownloadFileLenth(const char *url){
	double downloadFileLenth = 0;
	CURL *handle = curl_easy_init();
	curl_easy_setopt(handle, CURLOPT_URL, url);
	curl_easy_setopt(handle, CURLOPT_HEADER, 1);    //只需要header头
	curl_easy_setopt(handle, CURLOPT_NOBODY, 1);    //不需要body
	if (curl_easy_perform(handle) == CURLE_OK) 
	{
		curl_easy_getinfo(handle, CURLINFO_CONTENT_LENGTH_DOWNLOAD, &downloadFileLenth);
	} 
	else 
	{
		downloadFileLenth = -1;
	}
	return downloadFileLenth;
}
 
void* workThread(void* pData)
{
	tNode* pNode = (tNode*)pData;
 
	int res = curl_easy_perform(pNode->_curl);
 
	if ( res != 0 )
	{
 
	}
 
	curl_easy_cleanup(pNode->_curl);
 
	pthread_mutex_lock(&foo_mutex);
	threadCnt --;
	pthread_mutex_unlock(&foo_mutex);
	delete pNode;
	pthread_exit(0);
 
	return NULL;
}
 
bool downLoad(int threadNum, std::string _packageUrl, std::string _storagePath, std::string fileName )
{
	long fileLength = getDownloadFileLenth(_packageUrl.c_str());
 
	if ( fileLength <= 0 )
	{
		printf("get the file error...");
		return false;
	}
 
	
	// Create a file to save package.
	const string outFileName = _storagePath + fileName;
	FILE *fp = fopen(outFileName.c_str(), "wb");
	if (! fp)
	{
		return false;
	}
 
	//_chsize((int)fp, fileLength);
 
	int gap = fileLength / threadNum;
 
	for ( int i = 0; i <= threadNum; i ++ )
	{
		tNode* pNode = new tNode();
 
		if ( i < threadNum )
		{
			pNode->startidx = i * gap;
			pNode->maxidx = pNode->startidx - 1;
		}
		else
		{
			if ( fileLength % threadNum != 0 )
			{
				pNode->startidx = i * gap;
				pNode->maxidx = fileLength - 1;
			}
		}
 
		CURL* _curl = curl_easy_init();
 
		pNode->_curl = _curl;
		pNode->fp = fp;
 
		// Download pacakge
		curl_easy_setopt(_curl, CURLOPT_URL, _packageUrl.c_str());
		curl_easy_setopt(_curl, CURLOPT_WRITEFUNCTION, downLoadPackage);
		curl_easy_setopt(_curl, CURLOPT_WRITEDATA, pNode);
		curl_easy_setopt(_curl, CURLOPT_NOPROGRESS, false);
		curl_easy_setopt(_curl, CURLOPT_PROGRESSFUNCTION, assetsManagerProgressFunc);
		//curl_easy_setopt(_curl, CURLOPT_PROGRESSDATA, this);
		curl_easy_setopt(_curl, CURLOPT_NOSIGNAL, 1L);
		curl_easy_setopt(_curl, CURLOPT_LOW_SPEED_LIMIT, 1L);
		curl_easy_setopt(_curl, CURLOPT_LOW_SPEED_TIME, 5L);
 
		pthread_mutex_lock(&foo_mutex);
		threadCnt ++;
		pthread_mutex_unlock(&foo_mutex);
		int rc = pthread_create (&pNode->_tid, NULL, workThread,pNode);
	}
 
 
 
	if (bError)
	{
		fclose(fp);
		return false;
	}
 
	while (threadCnt >0)
	{
		Sleep(1000);
	}
 
	fclose(fp);
 
	printf("download succed......\n");
	return true;
}
 
int _tmain(int argc, _TCHAR* argv[])
{
	downLoad(10, "http://ardownload.adobe.com/pub/adobe/reader/win/11.x/11.0.01/en_US/AdbeRdr11001_en_US.exe", "./", "AdbeRdr11001_en_US.exe");
 
	getchar();
	return 0;
}