Is there a way to convert from UTF8 to ISO-8859-1?

Question

My software is getting some strings in UTF8 than I need to convert to ISO 8859 1. I know that UTF8 domain is bigger than ISO 8859. But the data in UTF8 has been previously

Answer 1

The following example uses iconv library also. It works even when you have a file (or input stream) that contains mixed UTF-8 and ISO-8859-1 characters (this could happen, for example, if you have an UTF-8 file and edit it in environement that uses ISO-8859-1).

int Utf8ToLatin1(char* input, char* output, size_t size)
{
    size_t in_left = size;
    size_t out_left = size;

    char *in_buf    = input;
    char *out_buf   = output;

    iconv_t cd = iconv_open("ISO_8859-1", "UTF-8");
    if (cd == (iconv_t)-1) {
        (void) fprintf(stderr, "iconv_open() failed, msg encoding will be kept!");
        strncpy(output, input, size);
        return -1;
    }

    do {
        if (iconv(cd, &in_buf, &in_left, &out_buf, &out_left) == (size_t) -1) {
            if (errno == EILSEQ) {
                /* Input conversion stopped due to an input byte that
                 * does not belong to the input codeset.
                 */
                printf("Input conversion stopped due to an input byte that does not belong to the input codeset.\n");
                *out_buf= *in_buf;
                out_buf++   ;out_left--;
                in_buf++    ;in_left--;

            } else if (errno == E2BIG) {
                /* Input conversion stopped due to lack of space in
                 * the output buffer.
                 */
                printf("Input conversion stopped due to lack of space in the output buffer.\n");
                perror("iconv failed!, propably the encoding is already Latin, msg encoding will be kept!\n");
                strncpy(output, input, size);
                return -1;
            } else if (errno == EINVAL) {
                /* Input conversion stopped due to an incomplete
                 * character or shift sequence at the end of the
                 * input buffer.
                 */
                printf("Input conversion stopped due to an incomplete character or shift sequence at the end of the input buffer.\n");
                *out_buf= *in_buf;
                out_buf++   ;out_left--;
                in_buf++    ;in_left--;
            }

        }
    } while (in_left > 0 && out_left > 0);
    *out_buf = 0;

    iconv_close(cd);

    printf("*********************************************************\n");
    printf("ISO-8859-1:\n %s\n", input, output);
    return 0;

}