From a5cb8b874ed422ba6f202f5cd0dc73e4689e168b Mon Sep 17 00:00:00 2001
From: Ingo Schwarze <schwarze@openbsd.org>
Date: Wed, 14 Jun 2017 22:51:25 +0000
Subject: Naive implementation of the roff(7) .po (page offset) request.

This clearly works when .po is called on the top level, but might
not be sophisticated enough if people call .po inside indentation-changing
contexts, but i haven't seen that in manual pages (yet :).
---
 roff_term.c | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

(limited to 'roff_term.c')

diff --git a/roff_term.c b/roff_term.c
index db59db08..0b0b6fda 100644
--- a/roff_term.c
+++ b/roff_term.c
@@ -1,4 +1,4 @@
-/*	$Id: roff_term.c,v 1.12 2017/06/14 17:51:15 schwarze Exp $ */
+/*	$Id: roff_term.c,v 1.13 2017/06/14 22:51:25 schwarze Exp $ */
 /*
  * Copyright (c) 2010, 2014, 2015, 2017 Ingo Schwarze <schwarze@openbsd.org>
  *
@@ -32,6 +32,7 @@ static	void	  roff_term_pre_ce(ROFF_TERM_ARGS);
 static	void	  roff_term_pre_ft(ROFF_TERM_ARGS);
 static	void	  roff_term_pre_ll(ROFF_TERM_ARGS);
 static	void	  roff_term_pre_mc(ROFF_TERM_ARGS);
+static	void	  roff_term_pre_po(ROFF_TERM_ARGS);
 static	void	  roff_term_pre_sp(ROFF_TERM_ARGS);
 static	void	  roff_term_pre_ta(ROFF_TERM_ARGS);
 static	void	  roff_term_pre_ti(ROFF_TERM_ARGS);
@@ -42,6 +43,7 @@ static	const roff_term_pre_fp roff_term_pre_acts[ROFF_MAX] = {
 	roff_term_pre_ft,  /* ft */
 	roff_term_pre_ll,  /* ll */
 	roff_term_pre_mc,  /* mc */
+	roff_term_pre_po,  /* po */
 	roff_term_pre_ce,  /* rj */
 	roff_term_pre_sp,  /* sp */
 	roff_term_pre_ta,  /* ta */
@@ -152,6 +154,28 @@ roff_term_pre_mc(ROFF_TERM_ARGS)
 		p->flags |= TERMP_ENDMC;
 }
 
+static void
+roff_term_pre_po(ROFF_TERM_ARGS)
+{
+	struct roffsu	 su;
+	static int	 po, polast;
+	int		 ponew;
+
+	if (n->child != NULL &&
+	    a2roffsu(n->child->string, &su, SCALE_EM) != NULL) {
+		ponew = term_hen(p, &su);
+		if (*n->child->string == '+' ||
+		    *n->child->string == '-')
+			ponew += po;
+	} else
+		ponew = polast;
+	polast = po;
+	po = ponew;
+
+	ponew = po - polast + (int)p->tcol->offset;
+	p->tcol->offset = ponew > 0 ? ponew : 0;
+}
+
 static void
 roff_term_pre_sp(ROFF_TERM_ARGS)
 {
-- 
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