===================================================================
RCS file: /cvs/mandoc/out.c,v
retrieving revision 1.56
retrieving revision 1.64
diff -u -p -r1.56 -r1.64
--- mandoc/out.c	2014/12/23 09:31:46	1.56
+++ mandoc/out.c	2017/06/08 12:54:58	1.64
@@ -1,7 +1,7 @@
-/*	$Id: out.c,v 1.56 2014/12/23 09:31:46 schwarze Exp $ */
+/*	$Id: out.c,v 1.64 2017/06/08 12:54:58 schwarze Exp $ */
 /*
  * Copyright (c) 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
- * Copyright (c) 2011, 2014 Ingo Schwarze <schwarze@openbsd.org>
+ * Copyright (c) 2011, 2014, 2015, 2017 Ingo Schwarze <schwarze@openbsd.org>
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -40,10 +40,10 @@ static	void	tblcalc_number(struct rofftbl *, struct ro
  * Parse the *src string and store a scaling unit into *dst.
  * If the string doesn't specify the unit, use the default.
  * If no default is specified, fail.
- * Return 2 on complete success, 1 when a conversion was done,
- * but there was trailing garbage, and 0 on total failure.
+ * Return a pointer to the byte after the last byte used,
+ * or NULL on total failure.
  */
-int
+const char *
 a2roffsu(const char *src, struct roffsu *dst, enum roffscale def)
 {
 	char		*endptr;
@@ -51,7 +51,7 @@ a2roffsu(const char *src, struct roffsu *dst, enum rof
 	dst->unit = def == SCALE_MAX ? SCALE_BU : def;
 	dst->scale = strtod(src, &endptr);
 	if (endptr == src)
-		return(0);
+		return NULL;
 
 	switch (*endptr++) {
 	case 'c':
@@ -89,15 +89,11 @@ a2roffsu(const char *src, struct roffsu *dst, enum rof
 		/* FALLTHROUGH */
 	default:
 		if (SCALE_MAX == def)
-			return(0);
+			return NULL;
 		dst->unit = def;
 		break;
 	}
-
-	/* FIXME: do this in the caller. */
-	if (dst->scale < 0.0)
-		dst->scale = 0.0;
-	return(*endptr == '\0' ? 2 : 1);
+	return endptr;
 }
 
 /*
@@ -110,11 +106,12 @@ void
 tblcalc(struct rofftbl *tbl, const struct tbl_span *sp,
 	size_t totalwidth)
 {
+	const struct tbl_opts	*opts;
 	const struct tbl_dat	*dp;
 	struct roffcol		*col;
 	size_t			 ewidth, xwidth;
 	int			 spans;
-	int			 icol, maxcol, necol, nxcol;
+	int			 icol, maxcol, necol, nxcol, quirkcol;
 
 	/*
 	 * Allocate the master column specifiers.  These will hold the
@@ -125,6 +122,7 @@ tblcalc(struct rofftbl *tbl, const struct tbl_span *sp
 	assert(NULL == tbl->cols);
 	tbl->cols = mandoc_calloc((size_t)sp->opts->cols,
 	    sizeof(struct roffcol));
+	opts = sp->opts;
 
 	for (maxcol = -1; sp; sp = sp->next) {
 		if (TBL_SPAN_DATA != sp->pos)
@@ -141,14 +139,14 @@ tblcalc(struct rofftbl *tbl, const struct tbl_span *sp
 			spans = dp->spans;
 			if (1 < spans)
 				continue;
-			icol = dp->layout->head->ident;
+			icol = dp->layout->col;
 			if (maxcol < icol)
 				maxcol = icol;
 			col = tbl->cols + icol;
 			col->flags |= dp->layout->flags;
 			if (dp->layout->flags & TBL_CELL_WIGN)
 				continue;
-			tblcalc_data(tbl, col, sp->opts, dp);
+			tblcalc_data(tbl, col, opts, dp);
 		}
 	}
 
@@ -198,13 +196,38 @@ tblcalc(struct rofftbl *tbl, const struct tbl_span *sp
 	 */
 
 	if (nxcol && totalwidth) {
-		xwidth = totalwidth - 3*maxcol - xwidth;
+		xwidth += 3*maxcol +
+		    (opts->opts & (TBL_OPT_BOX | TBL_OPT_DBOX) ?
+		     2 : !!opts->lvert + !!opts->rvert);
+		if (xwidth >= totalwidth)
+			return;
+		xwidth = totalwidth - xwidth;
+
+		/*
+		 * Emulate a bug in GNU tbl width calculation that
+		 * manifests itself for large numbers of x-columns.
+		 * Emulating it for 5 x-columns gives identical
+		 * behaviour for up to 6 x-columns.
+		 */
+
+		if (nxcol == 5) {
+			quirkcol = xwidth % nxcol + 2;
+			if (quirkcol != 3 && quirkcol != 4)
+				quirkcol = -1;
+		} else
+			quirkcol = -1;
+
+		necol = 0;
+		ewidth = 0;
 		for (icol = 0; icol <= maxcol; icol++) {
 			col = tbl->cols + icol;
 			if ( ! (col->flags & TBL_CELL_WMAX))
 				continue;
-			col->width = xwidth / nxcol--;
-			xwidth -= col->width;
+			col->width = (double)xwidth * ++necol / nxcol
+			    - ewidth + 0.4995;
+			if (necol == quirkcol)
+				col->width--;
+			ewidth += col->width;
 		}
 	}
 }
@@ -219,18 +242,14 @@ tblcalc_data(struct rofftbl *tbl, struct roffcol *col,
 
 	switch (dp->layout->pos) {
 	case TBL_CELL_HORIZ:
-		/* FALLTHROUGH */
 	case TBL_CELL_DHORIZ:
 		sz = (*tbl->len)(1, tbl->arg);
 		if (col->width < sz)
 			col->width = sz;
 		break;
 	case TBL_CELL_LONG:
-		/* FALLTHROUGH */
 	case TBL_CELL_CENTRE:
-		/* FALLTHROUGH */
 	case TBL_CELL_LEFT:
-		/* FALLTHROUGH */
 	case TBL_CELL_RIGHT:
 		tblcalc_literal(tbl, col, dp);
 		break;
@@ -241,7 +260,6 @@ tblcalc_data(struct rofftbl *tbl, struct roffcol *col,
 		break;
 	default:
 		abort();
-		/* NOTREACHED */
 	}
 }