// Copyright © 2010-2012 sss
// 
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
// 
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
// 
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.


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


int main(int argc, char **argv)
{
	int opt = -1;
	char ifile[256], ofile[256], fcharset[32], tcharset[32];
    memset(ifile, 0, sizeof(ifile));
    memset(ofile, 0, sizeof(ofile));
    memset(fcharset, 0, sizeof(fcharset));
    memset(tcharset, 0, sizeof(tcharset));

	ifile[0] = 0;
	ofile[0] = 0;
	fcharset[0] = 0;
	tcharset[0] = 0;
	while((opt = getopt(argc, argv, "i:o:f:t:")) != -1)
	{
		switch(opt)
		{
			case 'i':
			strncpy(ifile, optarg, sizeof(ifile) - 1);
			break;
			case 'o':
			strncpy(ofile, optarg, sizeof(ofile) - 1);
			break;
			case 'f':
			strncpy(fcharset, optarg, sizeof(fcharset) - 1);
			break;
			case 't':
			strncpy(tcharset, optarg, sizeof(tcharset) - 1);
			break;
			default:
			printf("usage: %s -ioft\n\t-i input file\n\t-o output file\n\t-f from charset\n\t-t to charset\n", argv[0]);
		}
	}
	iconv_t id = iconv_open(tcharset, fcharset);
	if((long)id == -1)
	{
		printf("failed to create iconv descriptor with error: %s\n", strerror(errno));
		return 1;
	}
	FILE *in = fopen(ifile, "r");
	if(!in)
	{
		printf("failed to open input file with error: %s\n", strerror(errno));
		return 1;
	}
	FILE *out = fopen(ofile, "w");
	if(!out)
	{
		printf("failed to open input file with error: %s\n", strerror(errno));
		return 1;
	}
	while(!feof(in))
	{
		char *buf, *outbuf, *op, *ip;

        buf = (char*)malloc(4096);
        if (!buf)
        {
            printf("failed to allocate memory for \"buf\"\n");
            return 1;
        }
        outbuf = (char*)malloc(4096);
        if (!outbuf)
        {
            printf("failed to allocate memory for \"outbuf\"");
            free(buf);
            return 1;
        }
		op = outbuf;
		ip = buf;
		if(!fgets(buf, 4096, in))
        {
            if (buf)
                free(buf);
            if (outbuf)
                free(outbuf);
			break;
        }
		size_t len = strlen(buf), outlen = 4096;
		int enc_len = iconv(id, &ip, &len, &op, &outlen);
		if(enc_len == -1)
		{
			printf("failed to convert buffer with error: %s\n", strerror(errno));
            free(buf);
            free(outbuf);
			return 1;
		}
		enc_len = 4096 - outlen;
		if((int)fwrite(outbuf, 1, enc_len, out) != enc_len)
		{
			printf("failed to write data to file with error: %s\n", strerror(errno));
            free(buf);
            free(outbuf);
			return 1;
		}
		free(buf);
		free(outbuf);
	}
	return 0;
}