For half and reverse line feeds, recognize SUSv2-style escape-digit

sequences in the input stream in addition to traditional BSD-style
escape-control-char sequences because traditional tools, for example
Heirloom roff, produce SUSv2-style sequences.  Switch the encoding
of forward half line feeds in the output of -f back to SUSv2 style
because that's likely to work with more tools than the non-standard
traditional BSD-style sequence.  Fully document these choices.

Issues originally reported by bapt at FreeBSD.
OK millert@ jmc@, and bapt@ also more or less agrees with the direction.

diff --git a/usr.bin/col/col.1 b/usr.bin/col/col.1
index 4ced073..e1db48d 100644 (file)
--- a/usr.bin/col/col.1
+++ b/usr.bin/col/col.1
@@ -1,4 +1,4 @@
-.\"    $OpenBSD: col.1,v 1.12 2014/10/17 21:10:56 schwarze Exp $
+.\"    $OpenBSD: col.1,v 1.13 2015/05/09 20:36:18 schwarze Exp $
 .\"    $NetBSD: col.1,v 1.4 1995/03/26 05:25:52 glass Exp $
 .\"
 .\" Copyright (c) 1990, 1993
@@ -33,7 +33,7 @@
 .\"
 .\"     @(#)col.1      8.1 (Berkeley) 6/29/93
 .\"
-.Dd $Mdocdate: October 17 2014 $
+.Dd $Mdocdate: May 9 2015 $
 .Dt COL 1
 .Os
 .Sh NAME
@@ -77,18 +77,33 @@ By default, 128 lines are buffered.
 Output multiple spaces instead of tabs.
 .El
 .Pp
-The control sequences for carriage motion that
+In the input stream,
 .Nm
-understands and their decimal ASCII values are listed in the following
-table:
+understands both the escape sequences of the form escape-digit
+mandated by
+.St -susv2
+and the traditional
+.Bx
+format escape-control-character.
+The control sequences for carriage motion and their ASCII values
+are as follows:
 .Pp
 .Bl -tag -width "escape-backspace" -compact
 .It escape\-bell
 Reverse line feed (27 then 7).
+.It escape\-digit\-7
+Reverse line feed (27 then 55).
 .It escape\-backspace
 Half reverse line feed (27 then 8).
+.It escape\-digit\-8
+Half reverse line feed (27 then 56).
 .It escape\-tab
 Half forward line feed (27 then 9).
+.It escape\-digit\-9
+Half forward line feed (27 then 57).
+In
+.Fl f
+mode, this sequence may also occur in the output stream.
 .It backspace
 Moves back one column (8); ignored in the first column.
 .It carriage return

diff --git a/usr.bin/col/col.c b/usr.bin/col/col.c
index 3f50cdb..f44d26a 100644 (file)
--- a/usr.bin/col/col.c
+++ b/usr.bin/col/col.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: col.c,v 1.16 2015/05/08 16:30:07 schwarze Exp $       */
+/*     $OpenBSD: col.c,v 1.17 2015/05/09 20:36:18 schwarze Exp $       */
 /*     $NetBSD: col.c,v 1.7 1995/09/02 05:48:50 jtc Exp $      */
 
 /*-
@@ -50,9 +50,6 @@
 #define        SI      '\017'          /* shift in to normal character set */
 #define        SO      '\016'          /* shift out to alternate character set */
 #define        VT      '\013'          /* vertical tab (aka reverse line feed) */
-#define        RLF     '\007'          /* ESC-07 reverse line feed */
-#define        RHLF    '\010'          /* ESC-010 reverse half-line feed */
-#define        FHLF    '\011'          /* ESC-011 forward half-line feed */
 
 /* build up at least this many lines before flushing them out */
 #define        BUFFER_MARGIN           32
@@ -165,14 +162,25 @@ main(int argc, char *argv[])
                                cur_col = 0;
                                continue;
                        case ESC:               /* just ignore EOF */
+                               /*
+                                * In the input stream, accept both the
+                                * XPG5 sequences ESC-digit and the
+                                * traditional BSD sequences ESC-ctrl.
+                                */
                                switch(getchar()) {
-                               case RLF:
+                               case '7':  /* reverse line feed */
+                                       /* FALLTHROUGH */
+                               case '\007':
                                        addto_lineno(&cur_line, -2);
                                        break;
-                               case RHLF:
+                               case '8':  /* reverse half-line feed */
+                                       /* FALLTHROUGH */
+                               case '\010':
                                        addto_lineno(&cur_line, -1);
                                        break;
-                               case FHLF:
+                               case '9':  /* forward half-line feed */
+                                       /* FALLTHROUGH */
+                               case '\011':
                                        addto_lineno(&cur_line, 1);
                                        if (cur_line > max_line)
                                                max_line = cur_line;
@@ -350,8 +358,12 @@ flush_blanks(void)
        for (i = nb; --i >= 0;)
                PUTC('\n');
        if (half) {
+               /*
+                * In the output stream, always generate
+                * escape sequences conforming to XPG5.
+                */
                PUTC(ESC);
-               PUTC('\011');
+               PUTC('9');
                if (!nb)
                        PUTC('\r');
        }