From 5aae14345a405f370fc687547d918a084ce6e53f Mon Sep 17 00:00:00 2001
From: Ingo Schwarze <schwarze@openbsd.org>
Date: Wed, 29 Apr 2015 18:35:00 +0000
Subject: Replace the kludge for the \z escape sequence by an actual
 implementation.  As a side effect, minus ten lines of code.

As another side effect, this also fixes the assertion failure that
used to be triggered by "\z\o'ab'c" at the beginning of an output
line, found by jsg@ with afl (test case 022/Apr27).
---
 term.c | 70 ++++++++++++++++++++++++++----------------------------------------
 1 file changed, 27 insertions(+), 43 deletions(-)

(limited to 'term.c')

diff --git a/term.c b/term.c
index 68f3ea04..79d116a3 100644
--- a/term.c
+++ b/term.c
@@ -1,4 +1,4 @@
-/*	$Id: term.c,v 1.247 2015/04/04 17:47:18 schwarze Exp $ */
+/*	$Id: term.c,v 1.248 2015/04/29 18:35:00 schwarze Exp $ */
 /*
  * Copyright (c) 2008, 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2010-2015 Ingo Schwarze <schwarze@openbsd.org>
@@ -265,6 +265,7 @@ term_flushln(struct termp *p)
 
 	p->col = 0;
 	p->overstep = 0;
+	p->flags &= ~(TERMP_BACKAFTER | TERMP_BACKBEFORE);
 
 	if ( ! (TERMP_NOBREAK & p->flags)) {
 		p->viscol = 0;
@@ -417,11 +418,6 @@ term_word(struct termp *p, const char *word)
 
 	while ('\0' != *word) {
 		if ('\\' != *word) {
-			if (TERMP_SKIPCHAR & p->flags) {
-				p->flags &= ~TERMP_SKIPCHAR;
-				word++;
-				continue;
-			}
 			if (TERMP_NBRWORD & p->flags) {
 				if (' ' == *word) {
 					encode(p, nbrsp, 1);
@@ -480,13 +476,13 @@ term_word(struct termp *p, const char *word)
 			term_fontlast(p);
 			continue;
 		case ESCAPE_NOSPACE:
-			if (TERMP_SKIPCHAR & p->flags)
-				p->flags &= ~TERMP_SKIPCHAR;
-			else if ('\0' == *word)
+			if (p->flags & TERMP_BACKAFTER)
+				p->flags &= ~TERMP_BACKAFTER;
+			else if (*word == '\0')
 				p->flags |= (TERMP_NOSPACE | TERMP_NONEWLINE);
 			continue;
 		case ESCAPE_SKIPCHAR:
-			p->flags |= TERMP_SKIPCHAR;
+			p->flags |= TERMP_BACKAFTER;
 			continue;
 		case ESCAPE_OVERSTRIKE:
 			cp = seq + sz;
@@ -496,9 +492,14 @@ term_word(struct termp *p, const char *word)
 					continue;
 				}
 				encode1(p, *seq++);
-				if (seq < cp)
-					encode(p, "\b", 1);
+				if (seq < cp) {
+					if (p->flags & TERMP_BACKBEFORE)
+						p->flags |= TERMP_BACKAFTER;
+					else
+						p->flags |= TERMP_BACKBEFORE;
+				}
 			}
+			continue;
 		default:
 			continue;
 		}
@@ -553,16 +554,16 @@ encode1(struct termp *p, int c)
 {
 	enum termfont	  f;
 
-	if (TERMP_SKIPCHAR & p->flags) {
-		p->flags &= ~TERMP_SKIPCHAR;
-		return;
-	}
+	if (p->col + 7 >= p->maxcols)
+		adjbuf(p, p->col + 7);
 
-	if (p->col + 6 >= p->maxcols)
-		adjbuf(p, p->col + 6);
-
-	f = p->fontq[p->fonti];
+	f = (c == ASCII_HYPH || isgraph(c)) ?
+	    p->fontq[p->fonti] : TERMFONT_NONE;
 
+	if (p->flags & TERMP_BACKBEFORE) {
+		p->buf[p->col++] = 8;
+		p->flags &= ~TERMP_BACKBEFORE;
+	}
 	if (TERMFONT_UNDER == f || TERMFONT_BI == f) {
 		p->buf[p->col++] = '_';
 		p->buf[p->col++] = 8;
@@ -575,6 +576,10 @@ encode1(struct termp *p, int c)
 		p->buf[p->col++] = 8;
 	}
 	p->buf[p->col++] = c;
+	if (p->flags & TERMP_BACKAFTER) {
+		p->flags |= TERMP_BACKBEFORE;
+		p->flags &= ~TERMP_BACKAFTER;
+	}
 }
 
 static void
@@ -582,29 +587,8 @@ encode(struct termp *p, const char *word, size_t sz)
 {
 	size_t		  i;
 
-	if (TERMP_SKIPCHAR & p->flags) {
-		p->flags &= ~TERMP_SKIPCHAR;
-		return;
-	}
-
-	/*
-	 * Encode and buffer a string of characters.  If the current
-	 * font mode is unset, buffer directly, else encode then buffer
-	 * character by character.
-	 */
-
-	if (p->fontq[p->fonti] == TERMFONT_NONE) {
-		if (p->col + sz >= p->maxcols)
-			adjbuf(p, p->col + sz);
-		for (i = 0; i < sz; i++)
-			p->buf[p->col++] = word[i];
-		return;
-	}
-
-	/* Pre-buffer, assuming worst-case. */
-
-	if (p->col + 1 + (sz * 5) >= p->maxcols)
-		adjbuf(p, p->col + 1 + (sz * 5));
+	if (p->col + 2 + (sz * 5) >= p->maxcols)
+		adjbuf(p, p->col + 2 + (sz * 5));
 
 	for (i = 0; i < sz; i++) {
 		if (ASCII_HYPH == word[i] ||
-- 
cgit v1.2.3-56-ge451