iconv 的使用注意

水深无声 2022-09-24 08:24 199阅读 0赞

#include <iconv.h>
    #include <stdio.h>
    #include <stdlib.h>
    #include <string.h>
    
    int main()
    {
    	 char *dest = NULL;
       size_t destSize = 0;
    	 char name[]= {0x52, 0x00, 0x6f, 0x00, 0x6f, 0x00, 0x74, 0x00}; // ROOT -- UNICODE编码
    	 iconv_t cd = NULL;
    
    	 cd = iconv_open("UTF8", "UNICODE");
    	 if((void*)-1 == cd)
       {
           return;
       }
    	 size_t a = (size_t)sizeof(name);
    	 char * sp = name ;
    	 char *outBuf = (char*)malloc(a * 4);
    
    	 printf("sp=%p, outbuf=%p\r\n", sp, outBuf);
    	 memset((void *)outBuf, 0, a* 4);
    	 size_t b =(size_t) (a*4); 
       printf("sp = %s, a=%d, b = %d\r\n",sp,  a, b);
    
    	 size_t n =  iconv(cd, &sp, &a, &outBuf, &b);
    	 printf("sp=%p,  outbuf=%p\r\n",sp, outBuf);
    	 printf("END-outBuf:%s, name = %s \r\n", outBuf, name);		
    	  return 0;
    }

我们来看一下 这段代码 最后的运行结果：

![Center][]

**我们可以 看到 再进行iconv函数 带入的指针 sp，outBuf 的 指针地址 都发生了改变 。 **

**我们具体看一下流程， sp指向了原name 的一个地址，那么带入到iconv时候，从unicode 到ytf-8 ，name的地址上数据发生了变化，但是原先带入的sp却指向了另外的地方**

**而，outBuf 是我们malloc出来的一个内存空间，将他带入到iconv 却没有得到我们要的结果  说明 outBuf的地址也发生了变化。 同理也需要一个中间变量的过度。**

完整代码 参见如下：

#include <iconv.h>
    #include <stdio.h>
    #include <stdlib.h>
    #include <string.h>
    
    int main()
    {
    	 char *dest = NULL;
       size_t destSize = 0;
    	 char name[]= {0x52, 0x00, 0x6f, 0x00, 0x6f, 0x00, 0x74, 0x00}; // ROOT -- UNICODE编码
    	 iconv_t cd = NULL;
    
    	 cd = iconv_open("UTF8", "UNICODE");
    	 if((void*)-1 == cd)
       {
           return;
       }
    	 size_t a = (size_t)sizeof(name);
    	 char * sp = name ;
    	 char *outBuf = (char*)malloc(a * 4);
       char *out = outBuf;
    	 printf("out: %p, outbuf=%p\r\n", out, outBuf);
    	 memset((void *)outBuf, 0, a* 4);
    	 size_t b =(size_t) (a*4); 
       printf("sp = %s, 111===%d, %d\r\n",sp,  a, b);
    	 printf("out: %p, outbuf=%p\r\n", out, outBuf);
    	 size_t n =  iconv(cd, &sp, &a, &out, &b);
    	 printf("out: %p, outbuf=%p\r\n", out, outBuf);
    	 printf("ENDL2 :%s, name = %s \r\n", outBuf, name);		
    	  return 0;
    }

具体iconv 的实现 参见 glibc库:    [https://github.com/vevenlcf/glibc/tree/master/iconv][https_github.com_vevenlcf_glibc_tree_master_iconv]

[Center]: /images/20220719/f49fdd9a7ea844a4ac1af4f0bff8eeb0.png
[https_github.com_vevenlcf_glibc_tree_master_iconv]: https://github.com/vevenlcf/glibc/tree/master/iconv