/******************************************************************************
 *
 * unicodertf -	SWFilter decendant to convert a double byte unicode file
 *				 to RTF tags
 */


#include <stdlib.h>
#include <stdio.h>
#include <unicodertf.h>

UnicodeRTF::UnicodeRTF() {
}


char UnicodeRTF::ProcessText(char *text, int maxlen, const SWKey *key, const SWModule *module)
{
	unsigned char *to, *from, *maxto;
	int len;
	char digit[10];
	short ch;	// must be signed per unicode spec (negative is ok for big numbers > 32768)

	len = strlenw(text) + 2;						// shift string to right of buffer
	if (len < maxlen) {
		memmove(&text[maxlen - len], text, len);
		from = (unsigned char*)&text[maxlen - len];
	}
	else	from = (unsigned char*)text;
	maxto =(unsigned char*)text + maxlen;

	// -------------------------------
	bool lastUni = false;
	for (to = (unsigned char*)text; *from && (to <= maxto); from++) {
		ch = 0;
		if ((*from & 128) != 128) {
//			if ((*from == ' ') && (lastUni))
//				*to++ = ' ';
			*to++ = *from;
			lastUni = false;
			continue;
		}
		if ((*from & 128) && ((*from & 64) != 64)) {
	    // error
			*from = 'x';
			continue;
		}
		*from <<= 1;
		int subsequent;
		for (subsequent = 1; (*from & 128); subsequent++) {
			*from <<= 1;
			from[subsequent] &= 63;
			ch <<= 6;
			ch |= from[subsequent];
		}
		subsequent--;
		*from <<=1;
		char significantFirstBits = 8 - (2+subsequent);
		
		ch |= (((short)*from) << (((6*subsequent)+significantFirstBits)-8));
		from += subsequent;
		*to++ = '\\';
		*to++ = 'u';
		sprintf(digit, "%d", ch);
		for (char *dig = digit; *dig; dig++)
			*to++ = *dig;
		*to++ = '?';
		lastUni = true;
	}
	   
	if (to != maxto) {
		*to++ = 0;
	}
	*to = 0;
	return 0;
}