/* exclude.c -
Exclusion checking.
Written by James Clark (jjc@jclark.com).
*/
#include "sgmlincl.h"
static int excktok P((struct thdr *, int, int *));
static int exmark P((int));
/* Check that the current exclusions are legal for the content model
of the current element. */
VOID exclude()
{
struct thdr *mod = tags[ts].tetd->etdmod;
if ((mod->ttype & MKEYWORD) == 0 && exmark(1)) {
int excl;
excktok(mod + 1, 0, &excl);
exmark(0);
}
}
/* Set the mark field of all current exclusions to val. Return 1 if
there are some current exclusions. */
static
int exmark(val)
int val;
{
int i;
int gotone = 0;
for (i = ts; i > 0; --i) {
struct etd **p = tags[i].tetd->etdmex;
if (p) {
for (; *p; p++)
(*p)->mark = val;
gotone = 1;
}
}
return gotone;
}
/* Check exclusions for this token. Return size of token. */
static
int excktok(t, orgrp, excl)
struct thdr *t;
int orgrp; /* 1 if token is member of or group */
int *excl; /* Set to 1 if token is excluded. */
{
int size;
struct thdr *tem;
int tnum;
int optional = 0;
int hadopt, hadreq;
*excl = 0;
switch (t->ttype & TTMASK) {
case TTETD:
if (t->tu.thetd->mark) {
if (orgrp || (t->ttype & TOPT))
*excl = 1;
else
sgmlerr(217, &pcbstag, t->tu.thetd->etdgi + 1,
tags[ts].tetd->etdgi + 1);
}
/* fall through */
case TTCHARS:
size = 1;
break;
case TTOR:
case TTAND:
case TTSEQ:
tem = t + 1;
hadopt = 0;
hadreq = 0;
for (tnum = t->tu.tnum; tnum > 0; --tnum) {
int ex;
int n = excktok(tem, (t->ttype & TTMASK) == TTOR, &ex);
if (!ex) {
if (tem->ttype & TOPT)
hadopt = 1;
else
hadreq = 1;
}
tem += n;
}
size = tem - t;
if ((t->ttype & TTMASK) == TTOR)
optional = hadreq ? hadopt : 1;
else
optional = !hadreq;
break;
default:
abort();
}
/* Was required, but exclusions have made it optional.
eg <!element foo - - (a | b) -(a, b)> */
if (optional && !(t->ttype & TOPT))
sgmlerr(216, &pcbstag, tags[ts].tetd->etdgi + 1, (UNCH *)0);
return size;
}
/*
Local Variables:
c-indent-level: 5
c-continued-statement-offset: 5
c-brace-offset: -5
c-argdecl-indent: 0
c-label-offset: -5
End:
*/