C使用libconv将iso ISO-8859-1转换为UTF-8

Question

我需要将拉丁语ISO-8859-1字符编码为UTF-8(以及相反的操作).

我第一次使用这个答案有没有办法从UTF8转换为iso-8859-1？执行操作,它的工作原理;

现在我想使用提供所有转换机制的libiconv,并且应该帮助我保持代码更简单.

我按照这里提供的示例: https://www.lemoda.net/c/iconv-example/iconv-example.html

我写了一个看起来像这样的方法:

char *iconvISO2UTF8(char *iso) {
    iconv_t iconvDesc = iconv_open ("ISO?8859-1", "UTF-8//TRANSLIT//IGNORE");

    if (iconvDesc == (iconv_t) - 1) {
        /* Something went wrong.  */
        if (errno == EINVAL)
            fprintf(stderr, "conversion from '%s' to '%s' not available", "ISO?8859?1", "UTF-8");           
        else
            fprintf(stderr, "LibIcon initialization failure");          

        return NULL;
    }

    size_t iconv_value;
    char * utf8;
    size_t len;
    size_t utf8len; 
    char * utf8start;

    int len_start;


    len = strlen (iso);
    if (! len) {        
        fprintf(stderr, "iconvISO2UTF8: input String is empty.");           
        return NULL;
    }

    /* Assign enough space to put the UTF-8. */
    utf8len = 2 * len;
    utf8 = calloc (utf8len, sizeof (char));
    if (! utf8) {
        fprintf(stderr, "iconvISO2UTF8: Calloc failed.");           
        return NULL;
    }
    /* Keep track of the variables. */
    utf8start = utf8;
    len_start = len;

    iconv_value = iconv (iconvDesc, & iso, & len, & utf8, & utf8len);
    /* Handle failures. */
    if (iconv_value == (size_t) - 1) {      
        switch (errno) {
                /* See "man 3 iconv" for an explanation. */
            case EILSEQ:
                fprintf(stderr, "iconv failed: Invalid multibyte sequence, in string '%s', length %d, out string '%s', length %d\n", iso, (int) len, utf8start, (int) utf8len);             
                break;
            case EINVAL:
                fprintf(stderr, "iconv failed: Incomplete multibyte sequence, in string '%s', length %d, out string '%s', length %d\n", iso, (int) len, utf8start, (int) utf8len);              
                break;
            case E2BIG:
                fprintf(stderr, "iconv failed: No more room, in string '%s', length %d, out string '%s', length %d\n", iso, (int)  len, utf8start, (int) utf8len);                              
                break;
            default:
                fprintf(stderr, "iconv failed, in string '%s', length %d, out string '%s', length %d\n", iso, (int) len, utf8start, (int) utf8len);                             
        }
        return NULL;
    }


    if(iconv_close (iconvDesc) != 0) {
        fprintf(stderr, "libicon close failed: %s", strerror (errno));          
    }

    return utf8start;

}

当我用普通的类似ascii的字符称之为"abracadabra"时,iconv有效.但是一旦我向它发送强调的字符,就像"éàèüöä"那么iconv()调用将失败并带有EILSEQ代码:

iconv失败:无效的多字节序列,字符串'éàèüöä',长度6,字符串'',长度12

下面是一个示例主程序,当存储在用ISO-8859-1编码的源文件中并在使用ISO-8859-1作为默认字符集的linux系统上编译时崩溃:

int main(int argc, char **argv) {
    char *iso1 = "abracadabra";
    char *utf = iconvISO2UTF8(iso1);
    puts(utf);
    free(utf);

    char *iso2 = "éàèüöä";
    utf = iconvISO2UTF8(iso2);
    puts(utf);
    free(utf);
}

是否可以使用iconv运行此类转换？如果是,这段代码有什么问题？

Answer 1

请仔细阅读iconv_open(3)手册页:

iconv_t iconv_open(const char *tocode, const char *fromcode);

如果您从ISO 8859-1转换为UTF-8,那么这是不一致的:

iconv_t iconvDesc = iconv_open ("ISO?8859-1", "UTF-8//TRANSLIT//IGNORE");

应该说

iconv_t iconvDesc = iconv_open ("UTF-8//TRANSLIT//IGNORE", "ISO?8859-1");