/* C program to read 
	ISO-8859-1 characters from a file file 
        and output UTF-8 encoded chars
	Note: the terminal window expects UTF-8

TO RUN, BE IN THIS DIRECTORY, AND TYPE:  ./iso2utf
 */

#include <stdio.h>
char * iso2utf(char* s, char c)
/*  convert one character c to possibly 2 bytes of utf-8
	and store in string starting at address s
	We need to return the advanced pointer
It would probably have been better to process a whole line,
with args of both string pointers, much like strcpy() */
{   char cc;
	if (c>=0)	// if leftmost bit is set, a char is regarded
			// as a negative number. This causes problems with shifting
	{   *s++ = c;			//  ascii char, 0xxxxxxx
	}
	else				//  extended,	1xxxxxxx
	{    *s++ = 0xC0 | (c>>6)&0x3;  /*  110yyy1x   (the y bits are 0)
					2 leftmost bits, shifted
					the extra mask is needed to 
					remove extended sign bits! */
	     *s++ = 0x80 | 0x3f & c;	//  10xxxxxx
	}
	return s;
}

int main()
{  FILE *in;
   int ch;
   char str[400];
   char* ptr=str;
   in = fopen("isotest.txt","r");   // a file created with ISO-8859-1 encoding
   while (EOF!= (ch = fgetc(in)))
   {	//printf("%c  %2x\n",ch, ch&0xff);  // debug stmt
	ptr=iso2utf(ptr, ch);
   }
   fclose(in);
   *ptr = '\0';			// terminate string
   printf(str);
   return 0;
}