用iconv做通用的语言编码转换(转)

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <iconv.h>

#ifndef ICONV_CONST
# define ICONV_CONST const
#endif

/*!
对字符串进行语言编码转换
param from   原始编码，比如"GB2312",的按照iconv支持的写
param to       转换的目的编码
param save   转换后的数据保存到这个指针里，需要在外部分配内存
param savelen 存储转换后数据的内存大小
param src       原始需要转换的字符串
param srclen     原始字符串长度
*/
int
convert(const char *from, const char *to, char* save, int savelen, char *src, int srclen)
{
     iconv_t cd;
    char   *inbuf = src;
    char *outbuf = save;
     size_t outbufsize = savelen;
    int status = 0;
     size_t   savesize = 0;
     size_t inbufsize = srclen;
    const char* inptr = inbuf;
     size_t       insize = inbufsize;
    char* outptr = outbuf;
     size_t outsize = outbufsize;
    
     cd = iconv_open(to, from);
     iconv(cd,NULL,NULL,NULL,NULL);
    if (inbufsize == 0) {
         status = -1;
        goto done;
     }
    while (insize > 0) {
         size_t res = iconv(cd,(ICONV_CONST char**)&inptr,&insize,&outptr,&outsize);
        if (outptr != outbuf) {
            int saved_errno = errno;
            int outsize = outptr - outbuf;
             strncpy(save+savesize, outbuf, outsize);
             errno = saved_errno;
         }
        if (res == (size_t)(-1)) {
            if (errno == EILSEQ) {
                int one = 1;
                 iconvctl(cd,ICONV_SET_DISCARD_ILSEQ,&one);
                 status = -3;
             } else if (errno == EINVAL) {
                if (inbufsize == 0) {
                     status = -4;
                    goto done;
                 } else {
                    break;
                 }
             } else if (errno == E2BIG) {
                 status = -5;
                goto done;
             } else {
                 status = -6;
                goto done;
             }
         }
     }
     status = strlen(save);
done:
     iconv_close(cd);
    return status;

}