Initial import of the CDE 2.1.30 sources from the Open Group.

cde/programs/dtdocbook/sgmls/exclude.c

@@ -0,0 +1,122 @@
+/* $XConsortium: exclude.c /main/3 1996/06/19 17:15:05 drk $ */
+/* 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:
+*/