/* thongs.c - manage and write out thong tables for gentlex.c */
/*
	Copyright Carnegie Mellon University 1992 - All rights reserved
	$Disclaimer: 
 * Permission to use, copy, modify, and distribute this software and its 
 * documentation for any purpose is hereby granted without fee, 
 * provided that the above copyright notice appear in all copies and that 
 * both that copyright notice, this permission notice, and the following 
 * disclaimer appear in supporting documentation, and that the names of 
 * IBM, Carnegie Mellon University, and other copyright holders, not be 
 * used in advertising or publicity pertaining to distribution of the software 
 * without specific, written prior permission.
 * 
 * IBM, CARNEGIE MELLON UNIVERSITY, AND THE OTHER COPYRIGHT HOLDERS 
 * DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING 
 * ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.  IN NO EVENT 
 * SHALL IBM, CARNEGIE MELLON UNIVERSITY, OR ANY OTHER COPYRIGHT HOLDER 
 * BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY 
 * DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, 
 * WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS 
 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE 
 * OF THIS SOFTWARE.
 *  $
*/
#ifndef NORCSID
	char *tlex_thongs_rcsid = "$Header: /afs/cs.cmu.edu/project/atk-dist/auis-6.3/atk/syntax/tlex/RCS/thongs.c,v 1.5 1992/12/19 21:51:43 wjh R6tape $";
#endif

/*
	Maintains the list -Thongs-  sorted in order by ->thong
		by adding elements with ThongAdd
	At end, writes the thong tables with ThongOut
*/

#include <stdio.h>

#include <global.h>
#include <gentlex.h>


static struct line *Thongs = NULL;	/* list of all thongs */
	/* each thong on the list has its ->action field pt
	   to a Hdr for the resulting action.  
	   These Hdrs are on the Classes list
	*/

/* compute the number of leading positions in which
	the two strings s and q are the same
*/
	static int
Similarity(s, q)
	char *s, *q;
{
	int n;
	for (n=0; *s && *s++ == *q++; n++) {}
	return n;
}

/* ThongAdd(thong, action, fromset)
	adds the given thong with the given action
	Copies the text of the offered thong.
	If the thong is one character long and there is no
	conflict, the action is simply stored in Actions array.
	If lineno is zero in an action, it is assumed to be
		a replaceable default.
	However, a warning is given if the replacement
		has fromset TRUE.  
	Thus there will be a warning if a set overrides one
		of the entries made from the .tab.c file.
	Returns a pointer to a struct line representing the action;
	it may be the original Hdr or it may be a Thong.
*/
	struct line *
ThongAdd(thong, action, fromset)
	char *thong;
	struct line *action;
	boolean fromset;
{
	struct line *tx, *prevx;
	struct line *tl;

	tl = Actions[UNSIGN(*thong)];
	if (tl == NULL && thong[1] == '\0') {
		/* just store as an action */
		Actions[UNSIGN(*thong)] = action;
		return;
	}
	
	if (tl == NULL || tl->type != Thong) {
		/* Create the thong entry for single character */
		tl = (struct line *)malloc(sizeof(struct line));
		tl->lineno = 0;
		tl->type = Thong;
		tl->u.g.thong = (char *)malloc(2);
		tl->u.g.thong[0] = *thong;
		tl->u.g.thong[1] = '\0';
		tl->u.g.hdr = Actions[UNSIGN(*thong)];
		tl->u.g.index = -1;	/* assigned later */
		tl->next = Thongs;
		Thongs = tl;
		Actions[UNSIGN(*thong)] = tl;
	}
	/* tl is the struct line of ->type==Thong 
			for the single character *thong */

	/* find insertion location in table */
	prevx = NULL;
	for (tx = tl; tx; tx = tx->next)
		if (*tx->u.g.thong != *thong)
			break;
		else if (strcmp(tx->u.g.thong, thong) >= 0)
			break;
		else prevx = tx;

	if (tx && strcmp(tx->u.g.thong, thong) == 0) {
		/* we have two actions for one string
			either may be an overridable default
			as indicated by having a ->lineno == 0
		    if the existing action is NULL, we are now 
			specifying an action for a single character
			not previously given an action  */
		if (tx->u.g.hdr == NULL)
			tx->u.g.hdr = action;
		else if (tx->u.g.hdr->lineno == 0) {
			/* the old one was overridable */
			tx->u.g.hdr = action;
			if (fromset)  ErrorA(WARNING, 
				"Set specifies character also used as token", 
				thong);
		}
		else if (action->lineno == 0) {
			/* the new one is overridable, leave the old */
		}
		else {
			int tlin = LineNo;
			LineNo = action->lineno;
			ErrorA(ERROR, "two actions for thong", tx->u.g.thong);
			LineNo = tlin;
		}
	}
	else {
		/* this string has never had an action defined:
			make a new entry in thongs list */
		tl = (struct line *)malloc(sizeof (struct line));
		tl->next = tx;
		tl->lineno = 0;
		tl->type = Thong;
		tl->u.g.thong = freeze(thong, NULL);
		tl->u.g.hdr = action;
		tl->u.g.index = -1;
		prevx->next = tl;
			/* if prevx == NULL, something is very wrong */
	}
}

/* ThongReplaceNulls(hdr)
	replace null actions in Thongs list with hdr
*/
	void
ThongReplaceNulls(hdr)
	struct line *hdr;
{
	struct line *tx;
	for (tx = Thongs; tx; tx = tx->next)
		if (tx->u.g.hdr == NULL)
			tx->u.g.hdr = hdr;
}


/* ThongOut - generate tables
	tlex_thongtbl,  tlex_thongsame,  tlex_thongact
with the form:
	static char *tlex_thongtbl[] = {
		"/", ".9", ... ""
	};
	static char tlex_thongsame[] = {
		0, 0, ..., 0
	};
	static short tlex_thongact[] = {
		13, N, ... 0
	};
    assign u.g.index values
*/

	void
ThongOut(f)
	FILE *f;
{
	int len, tlen;
	int index;
	struct line *tx;
	char *es, *prev;

	/* thongtbl */
	fprintf(f, "static char *%s_thongtbl[] = {", Prefix);
	index = 0;
	for (tx = Thongs; tx; tx = tx->next) {
		tx->u.g.index = index++;	/* assign index value */
		es = Escapify(tx->u.g.thong, &tlen);

		if (tx->u.g.thong[1] == '\0') {
			/* one character thong; start a group */
			fprintf(f, "\n\t/* %d */ ",
					tlex_ACTTHONG | tx->u.g.index);
			len = 18;
		}
		if (len + tlen > 65) {
			fprintf(f, "\n\t");
			len = 8;
		}
		fprintf(f, "\"%s\"", es);
		fprintf(f, ", ");
		len += tlen + 4;
	}
	fprintf(f, "\"\"};\n");

	/* thongsame */
	prev = "";
	fprintf(f, "static char %s_thongsame[] = {\n\t", Prefix);
	len = 8;	/* (8 for the \t in thongcon) */
	for (tx = Thongs; tx; tx = tx->next) {
		if (len + 3 > 75) {
			fprintf(f, "\n\t");
			len = 8;
		}
		fprintf(f, "%d", Similarity(prev, tx->u.g.thong));
		prev = tx->u.g.thong;
		fprintf(f, ", ");
		len += 3;
	}
	fprintf(f, "0};\n");

	/* thongact */
	fprintf(f, "static short %s_thongact[] = {\n\t", Prefix);
	len = 8;	/* (8 for the \t in thongcon) */
	for (tx = Thongs; tx; tx = tx->next) {
		if (len + 5 > 64) {
			fprintf(f, "\n\t");
			len = 8;
		}
		fprintf(f, "%d", tx->u.g.hdr->u.h.action);
		fprintf(f, ", ");
		len += 5;
	}
	fprintf(f, "0};\n");
}

/* ThongAction -  compute action array entry for the given character
	value is   tlex_THONG | (index in thong table of entry)
*/
	int
ThongAction(thong)
	struct line *thong;
{
	return tlex_ACTTHONG | thong->u.g.index;
}