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Re: [PATCH] TUI: Expand TABs into spaces
- From: Eli Zaretskii <eliz at gnu dot org>
- To: Doug Evans <xdje42 at gmail dot com>
- Cc: gdb-patches at sourceware dot org
- Date: Mon, 26 Jan 2015 09:29:28 +0200
- Subject: Re: [PATCH] TUI: Expand TABs into spaces
- Authentication-results: sourceware.org; auth=none
- References: <83k3149k5b dot fsf at gnu dot org> <837fwn2cvc dot fsf at gnu dot org> <CAP9bCMSbzc3q5CmJQDZyL0utP_x6Sp8ekHaTHzJHyVCJRwwcWA at mail dot gmail dot com> <83a918s6k5 dot fsf at gnu dot org> <m3h9vfamzs dot fsf at sspiff dot org>
- Reply-to: Eli Zaretskii <eliz at gnu dot org>
> From: Doug Evans <xdje42@gmail.com>
> Cc: gdb-patches@sourceware.org
> Date: Sat, 24 Jan 2015 13:26:47 -0800
>
> For tui_register_format it used to be such a straightforward function,
> it's a shame to grow it by 2x for bitfiddly tab handling.
>
> Let's add a helper routine that takes one string and returns
> another with tabs expanded, and put this helper routine in, say tui-io.c
> (this routine isn't tui-regs specific), and then call that routine from
> tui_register_format.
I did that below, but since tui_register_format is its only user,
keeping that function in tui-regs.c would have allowed us to make it
static. Wouldn't that be slightly better?
Thanks for the review; updated patch attached.
2015-01-26 Eli Zaretskii <eliz@gnu.org>
* tui/tui-io.c (tui_expand_tabs): New function.
(tui_puts, tui_redisplay_readline): Expand TABs into the
appropriate number of spaces.
* tui/tui-regs.c: Include tui-io.h.
(tui_register_format): Call tui_expand_tabs to expand TABs into
the appropriate number of spaces.
* tui/tui-io.h: Add prototype for tui_expand_tabs.
--- tui/tui-io.c~0 Wed Oct 29 21:45:50 2014
+++ tui/tui-io.c Mon Jan 26 09:10:34 2015
@@ -179,7 +179,20 @@ tui_puts (const char *string)
else if (tui_skip_line != 1)
{
tui_skip_line = -1;
- waddch (w, c);
+ /* Expand TABs, since ncurses on MS-Windows doesn't. */
+ if (c == '\t')
+ {
+ int line, col;
+
+ getyx (w, line, col);
+ do
+ {
+ waddch (w, ' ');
+ col++;
+ } while ((col % 8) != 0);
+ }
+ else
+ waddch (w, c);
}
else if (c == '\n')
tui_skip_line = -1;
@@ -254,6 +269,16 @@ tui_redisplay_readline (void)
waddch (w, '^');
waddch (w, CTRL_CHAR (c) ? UNCTRL (c) : '?');
}
+ else if (c == '\t')
+ {
+ /* Expand TABs, since ncurses on MS-Windows doesn't. */
+ getyx (w, line, col);
+ do
+ {
+ waddch (w, ' ');
+ col++;
+ } while ((col % 8) != 0);
+ }
else
{
waddch (w, c);
@@ -700,6 +725,58 @@ tui_getc (FILE *fp)
return ch;
}
+/* Utility function to expand TABs in a STRING into spaces. STRING
+ will be displayed starting at column COL. The returned expanded
+ string is malloc'ed. */
+char *
+tui_expand_tabs (const char *string, int col)
+{
+ int n_adjust;
+ const char *s;
+ char *ret, *q;
+
+ /* 1. How many additional characters do we need? */
+ for (n_adjust = 0, s = string; s; )
+ {
+ s = strpbrk (s, "\t");
+ if (s)
+ {
+ col += (s - string) + n_adjust;
+ /* Adjustment for the next tab stop, minus one for the TAB
+ we replace with spaces. */
+ n_adjust += 8 - (col % 8) - 1;
+ s++;
+ }
+ }
+
+ /* Allocate the copy. */
+ ret = q = xmalloc (strlen (string) + n_adjust + 1);
+
+ /* 2. Copy the original string while replacing TABs with spaces. */
+ for (s = string; s; )
+ {
+ char *s1 = strpbrk (s, "\t");
+ if (s1)
+ {
+ if (s1 > s)
+ {
+ strncpy (q, s, s1 - s);
+ q += s1 - s;
+ col += s1 - s;
+ }
+ do {
+ *q++ = ' ';
+ col++;
+ } while ((col % 8) != 0);
+ s1++;
+ }
+ else
+ strcpy (q, s);
+ s = s1;
+ }
+
+ return ret;
+}
/* Cleanup when a resize has occured.
Returns the character that must be processed. */
--- tui/tui-regs.c~0 Wed Oct 29 21:45:50 2014
+++ tui/tui-regs.c Mon Jan 26 09:24:23 2015
@@ -37,6 +37,7 @@
#include "tui/tui-wingeneral.h"
#include "tui/tui-file.h"
#include "tui/tui-regs.h"
+#include "tui/tui-io.h"
#include "reggroups.h"
#include "valprint.h"
@@ -694,7 +695,9 @@ tui_register_format (struct frame_info *
if (s && s[1] == 0)
*s = 0;
- ret = xstrdup (p);
+ /* Expand tabs into spaces, since ncurses on MS-Windows doesn't. */
+ ret = tui_expand_tabs (p, 0);
+
do_cleanups (cleanups);
return ret;
--- tui/tui-io.h~0 Wed Jun 11 19:34:41 2014
+++ tui/tui-io.h Mon Jan 26 09:11:42 2015
@@ -41,6 +41,9 @@
changed the edited text. */
extern void tui_redisplay_readline (void);
+/* Expand TABs into spaces. */
+extern char *tui_expand_tabs (const char *, int);
+
extern struct ui_out *tui_out;
extern struct ui_out *tui_old_uiout;