Rudimentary implementation of the e, x, and z table layout modifiers

to equalize, maximize, and ignore the width of columns.
Does not yet take vertical rulers into account,
and does not do line breaks within table cells.
Considerably improves the lftp(1) manual; issue noticed by sthen@.

7 files changed, 91 insertions, 11 deletions

diff --git a/mandoc.h b/mandoc.h
index bb8e51a2..21b131ab 100644
--- a/mandoc.h
+++ b/mandoc.h
@@ -246,6 +246,7 @@ struct	tbl_cell {
 #define	TBL_CELL_EQUAL	 (1 << 4) /* e, E */
 #define	TBL_CELL_UP	 (1 << 5) /* u, U */
 #define	TBL_CELL_WIGN	 (1 << 6) /* z, Z */
+#define	TBL_CELL_WMAX	 (1 << 7) /* x, X */
 	struct tbl_head	 *head;
 };
 
diff --git a/out.c b/out.c
index cd33710e..69bda82e 100644
--- a/out.c
+++ b/out.c
@@ -1,7 +1,7 @@
 /*	$Id$ */
 /*
  * Copyright (c) 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
- * Copyright (c) 2011 Ingo Schwarze <schwarze@openbsd.org>
+ * Copyright (c) 2011, 2014 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
@@ -139,11 +139,14 @@ a2roffsu(const char *src, struct roffsu *dst, enum roffscale def)
  * used for the actual width calculations.
  */
 void
-tblcalc(struct rofftbl *tbl, const struct tbl_span *sp)
+tblcalc(struct rofftbl *tbl, const struct tbl_span *sp,
+	size_t totalwidth)
 {
 	const struct tbl_dat	*dp;
 	struct roffcol		*col;
+	size_t			 ewidth, xwidth;
 	int			 spans;
+	int			 icol, maxcol, necol, nxcol;
 
 	/*
 	 * Allocate the master column specifiers.  These will hold the
@@ -155,7 +158,7 @@ tblcalc(struct rofftbl *tbl, const struct tbl_span *sp)
 	tbl->cols = mandoc_calloc((size_t)sp->opts->cols,
 	    sizeof(struct roffcol));
 
-	for ( ; sp; sp = sp->next) {
+	for (maxcol = 0; sp; sp = sp->next) {
 		if (TBL_SPAN_DATA != sp->pos)
 			continue;
 		spans = 1;
@@ -170,11 +173,72 @@ tblcalc(struct rofftbl *tbl, const struct tbl_span *sp)
 			spans = dp->spans;
 			if (1 < spans)
 				continue;
-			assert(dp->layout);
-			col = &tbl->cols[dp->layout->head->ident];
+			icol = dp->layout->head->ident;
+			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);
 		}
 	}
+
+	/*
+	 * Count columns to equalize and columns to maximize.
+	 * Find maximum width of the columns to equalize.
+	 * Find total width of the columns *not* to maximize.
+	 */
+
+	necol = nxcol = 0;
+	ewidth = xwidth = 0;
+	for (icol = 0; icol <= maxcol; icol++) {
+		col = tbl->cols + icol;
+		if (col->flags & TBL_CELL_EQUAL) {
+			necol++;
+			if (ewidth < col->width)
+				ewidth = col->width;
+		}
+		if (col->flags & TBL_CELL_WMAX)
+			nxcol++;
+		else
+			xwidth += col->width;
+	}
+
+	/*
+	 * Equalize columns, if requested for any of them.
+	 * Update total width of the columns not to maximize.
+	 */
+
+	if (necol) {
+		for (icol = 0; icol <= maxcol; icol++) {
+			col = tbl->cols + icol;
+			if ( ! (col->flags & TBL_CELL_EQUAL))
+				continue;
+			if (col->width == ewidth)
+				continue;
+			if (nxcol && totalwidth)
+				xwidth += ewidth - col->width;
+			col->width = ewidth;
+		}
+	}
+
+	/*
+	 * If there are any columns to maximize, find the total
+	 * available width, deducting 3n margins between columns.
+	 * Distribute the available width evenly.
+	 */
+
+	if (nxcol && totalwidth) {
+		xwidth = totalwidth - 3*maxcol - xwidth;
+		for (icol = 0; icol <= maxcol; icol++) {
+			col = tbl->cols + icol;
+			if ( ! (col->flags & TBL_CELL_WMAX))
+				continue;
+			col->width = xwidth / nxcol--;
+			xwidth -= col->width;
+		}
+	}
 }
 
 static void
diff --git a/out.h b/out.h
index 12a2f43f..f5cb962a 100644
--- a/out.h
+++ b/out.h
@@ -34,6 +34,7 @@ enum	roffscale {
 struct	roffcol {
 	size_t		 width; /* width of cell */
 	size_t		 decimal; /* decimal position in cell */
+	int		 flags; /* layout flags, see tbl_cell */
 };
 
 struct	roffsu {
@@ -64,7 +65,8 @@ __BEGIN_DECLS
 	while (/* CONSTCOND */ 0)
 
 int		  a2roffsu(const char *, struct roffsu *, enum roffscale);
-void		  tblcalc(struct rofftbl *tbl, const struct tbl_span *);
+void		  tblcalc(struct rofftbl *tbl,
+			const struct tbl_span *, size_t);
 
 __END_DECLS
 
diff --git a/tbl.7 b/tbl.7
index 5157f1bb..986ed674 100644
--- a/tbl.7
+++ b/tbl.7
@@ -248,6 +248,11 @@ The following case-insensitive modifier keys are available:
 .Bl -tag -width 2n
 .It Cm b
 Use a bold font for the contents of this column.
+.It Cm e
+Make this column wider to match the maximum width
+of any other column also having the
+.Cm e
+modifier.
 .It Cm f
 The next character selects the font to use for this column.
 See the
@@ -255,16 +260,21 @@ See the
 manual for supported one-character font names.
 .It Cm i
 Use an italic font for the contents of this column.
+.It Cm x
+After determining the width of all other columns, distribute the
+rest of the line length among all columns having the
+.Cm x
+modifier.
+.It Cm z
+Do not use this cell for determining the width of this column.
 .El
 .Pp
 The modifiers
 .Cm d ,
-.Cm e ,
-.Cm r ,
 .Cm t ,
 .Cm u ,
 and
-.Cm z
+.Cm w
 are ignored by
 .Xr mandoc 1 .
 .Pp
diff --git a/tbl_html.c b/tbl_html.c
index 033946de..03dd203e 100644
--- a/tbl_html.c
+++ b/tbl_html.c
@@ -57,7 +57,7 @@ html_tblopen(struct html *h, const struct tbl_span *sp)
 	if (TBL_SPAN_FIRST & sp->flags) {
 		h->tbl.len = html_tbl_len;
 		h->tbl.slen = html_tbl_strlen;
-		tblcalc(&h->tbl, sp);
+		tblcalc(&h->tbl, sp, 0);
 	}
 
 	assert(NULL == h->tblt);
diff --git a/tbl_layout.c b/tbl_layout.c
index b78e8881..004f33cc 100644
--- a/tbl_layout.c
+++ b/tbl_layout.c
@@ -168,6 +168,9 @@ mod:
 		goto mod;
 	case 'w':  /* XXX for now, ignore minimal column width */
 		goto mod;
+	case 'x':
+		cp->flags |= TBL_CELL_WMAX;
+		goto mod;
 	case 'f':
 		break;
 	case 'r':
diff --git a/tbl_term.c b/tbl_term.c
index 52ef73ca..31dabe81 100644
--- a/tbl_term.c
+++ b/tbl_term.c
@@ -91,7 +91,7 @@ term_tbl(struct termp *tp, const struct tbl_span *sp)
 		tp->tbl.slen = term_tbl_strlen;
 		tp->tbl.arg = tp;
 
-		tblcalc(&tp->tbl, sp);
+		tblcalc(&tp->tbl, sp, rmargin - tp->offset);
 	}
 
 	/* Horizontal frame at the start of boxed tables. */