libcurl下载到内存(二)

针对上一篇文章libcurl下载到内存(一)，略显得有点罗唆，我们采用最简单的办法修改对应的getinmem.c文件，来实现上述功能：

/*****************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 * $Id: getinmemory.c,v 1.12 2007-11-07 04:53:37 danf Exp $
 *
 * Example source code to show how the callback function can be used to
 * download data into a chunk of memory instead of storing it in a file.
 *
 * This exact source code has not been verified to work.
 */

#include
#include
#include

#include
#include
#include

struct MemoryStruct {
  char *memory;
  size_t size;
};

//添加一个全局变量

struct MemoryStruct chunk;

static void *myrealloc(void *ptr, size_t size)
{
  /* There might be a realloc() out there that doesn't like reallocing
     NULL pointers, so we take care of it here */
  if(ptr)
    return realloc(ptr, size);
  else
    return malloc(size);
}

static size_t
WriteMemoryCallback(void *ptr, size_t size, size_t nmemb, void *data)
{
  size_t realsize = size * nmemb;
 //我们给定了一个足够大的内存，不需要重新申请

//struct MemoryStruct *mem = (struct MemoryStruct *)data;

  mem->memory = (char *)myrealloc(mem->memory, mem->size + realsize + 1);
  if (mem->memory) {
    memcpy(&(mem->memory[mem->size]), ptr, realsize);
    mem->size += realsize;
    mem->memory[mem->size] = 0;
  }
  return realsize;
}

 

//int main(int argc, char **argv)
int getFileInBuffer(char * buffer)

{
  CURL *curl_handle;

//取消原来的注释

  //struct MemoryStruct chunk;

//根据传递的buffer进行初始化

  chunk.memory=NULL; /* we expect realloc(NULL, size) to work */
  chunk.size = 0;    /* no data at this point */

  curl_global_init(CURL_GLOBAL_ALL);

  /* init the curl session */
  curl_handle = curl_easy_init();

  /* specify URL to get */
  curl_easy_setopt(curl_handle, CURLOPT_URL, "");

  /* send all data to this function  */
  curl_easy_setopt(curl_handle, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);

  /* we pass our 'chunk' struct to the callback function */
  curl_easy_setopt(curl_handle, CURLOPT_WRITEDATA, (void *)&chunk);

  /* some servers don't like requests that are made without a user-agent
     field, so we provide one */
  curl_easy_setopt(curl_handle, CURLOPT_USERAGENT, "libcurl-agent/1.0");

  /* get it! */
  curl_easy_perform(curl_handle);

  /* cleanup curl stuff */
  curl_easy_cleanup(curl_handle);

  /*
   * Now, our chunk.memory points to a memory block that is chunk.size
   * bytes big and contains the remote file.
   *
   * Do something nice with it!
   *
   * You should be aware of the fact that at this point we might have an
   * allocated data block, and nothing has yet deallocated that data. So when
   * you're done with it, you should free() it as a nice application.
   */

  if(chunk.memory)
    free(chunk.memory);

  /* we're done with libcurl, so clean it up */
  curl_global_cleanup();

  return chunk.size;
}
这样我们就可以把我们要的内容保存在buffer内存中，然后执行你想要的操作就可以了：

char buffer[1024 * 10];

....

int size = getFileInBuffer(buffer);

....

全文完