gistfile1.txt

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



char* convert(const char *from_charset, const char *to_charset, const char *input) {
	size_t inleft, outleft, converted = 0;
	char *output, *outbuf, *tmp;
	const char *inbuf;
	size_t outlen;
	iconv_t cd;
	int errno;

	if ((cd = iconv_open(to_charset, from_charset)) == (iconv_t) -1)
		return NULL;

	inleft = strlen(input);
	inbuf = input;

	/* we'll start off allocating an output buffer which is the same size
	 * as our input buffer. */
	outlen = inleft;

	/* we allocate 4 bytes more than what we need for nul-termination... */
	if (!(output = (char*) malloc(outlen + 4))) {
		iconv_close(cd);
		return NULL;
	}

	do {
		errno = 0;
		outbuf = output + converted;
		outleft = outlen - converted;

		converted = iconv(cd, (char **) &inbuf, &inleft, &outbuf, &outleft);
		if (converted != (size_t) -1 || errno == EINVAL) {
			/*
			 * EINVAL  An  incomplete  multibyte sequence has been encoun­-
			 *         tered in the input.
			 *
			 * We'll just truncate it and ignore it.
			 */
			break;
		}

		if (errno != E2BIG) {
			/*
			 * EILSEQ An invalid multibyte sequence has been  encountered
			 *        in the input.
			 *
			 * Bad input, we can't really recover from this.
			 */
			iconv_close(cd);
			free(output);
			return NULL;
		}

		/*
		 * E2BIG   There is not sufficient room at *outbuf.
		 *
		 * We just need to grow our outbuffer and try again.
		 */

		converted = outbuf - output;
		outlen += inleft * 2 + 8;

		if (!(tmp = (char*) realloc(output, outlen + 4))) {
			iconv_close(cd);
			free(output);
			return NULL;
		}

		output = tmp;
		outbuf = output + converted;
	} while (1);

	/* flush the iconv conversion */
	iconv(cd, NULL, NULL, &outbuf, &outleft);
	iconv_close(cd);

	/* Note: not all charsets can be nul-terminated with a single
	 * nul byte. UCS2, for example, needs 2 nul bytes and UCS4
	 * needs 4. I hope that 4 nul bytes is enough to terminate all
	 * multibyte charsets? */

	/* nul-terminate the string */
	memset(outbuf, 0, 4);

	return output;
}

int main() {
	//char input[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ[]^_`abcdefghijklmnopqrstuvwxyz{|}~€‚„…†‡‰Š‹ŚŤŽŹ‘’“”•–—™š›śťžźˇ˘Ł¤Ą¦§¨©Ş«¬®Ż°±˛ł´µ¶·¸ąş»Ľ˝ľżŔÁÂĂÄĹĆÇČÉĘËĚÍÎĎĐŃŇÓÔŐÖ×ŘŮÚŰÜÝŢßŕáâăäĺćçčéęëěíîďđńňóôőö÷řůúűüýţ";
	char input[] = "caffc8f] はれひほふ\n Author: A U Thor <author@example.com>";
	//char *encoding= "cp1250";
	char *encoding = "ISO-2022-JP";
	
	char* outputCp = convert("UTF-8", encoding, input);

	printf("Input: %s\n", input);
	printf("UTF-8 -> %s: %s\n", encoding, outputCp);

	char* outputUtf8 = convert(encoding, "UTF-8", outputCp);
	printf("UTF-8 -> %s -> UTF-8: %s\n", encoding, outputUtf8);

        if (strcmp(outputUtf8, input) == 0) {
                printf("Input and output are identical\n");
        } else {
                printf("Output DOESN'T match with the input\n");
        }
	
	return 0;
}