Fix handling of leading #s when working out width.

diff --git a/usr.bin/tmux/format-draw.c b/usr.bin/tmux/format-draw.c
index b921fc9..057ad79 100644 (file)
--- a/usr.bin/tmux/format-draw.c
+++ b/usr.bin/tmux/format-draw.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: format-draw.c,v 1.23 2021/03/11 06:41:04 nicm Exp $ */
+/* $OpenBSD: format-draw.c,v 1.24 2021/08/22 15:33:14 nicm Exp $ */
 
 /*
  * Copyright (c) 2019 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -632,6 +632,36 @@ format_draw_absolute_centre(struct screen_write_ctx *octx, u_int available,
            width_after);
 }
 
+/* Get width and count of any leading #s. */
+static const char *
+format_leading_hashes(const char *cp, u_int *n, u_int *width)
+{
+       for (*n = 0; cp[*n] == '#'; (*n)++)
+               /* nothing */;
+       if (*n == 0) {
+               *width = 0;
+               return (cp);
+       }
+       if (cp[*n] != '[') {
+               if ((*n % 2) == 0)
+                       *width = (*n / 2);
+               else
+                       *width = (*n / 2) + 1;
+               return (cp + *n);
+       }
+       *width = (*n / 2);
+       if ((*n % 2) == 0) {
+               /*
+                * An even number of #s means that all #s are escaped, so not a
+                * style. The caller should not skip this. Return pointing to
+                * the [.
+                */
+               return (cp + *n);
+       }
+       /* This is a style, so return pointing to the #. */
+       return (cp + *n - 1);
+}
+
 /* Draw multiple characters. */
 static void
 format_draw_many(struct screen_write_ctx *ctx, struct style *sy, char ch,
@@ -1002,37 +1032,22 @@ u_int
 format_width(const char *expanded)
 {
        const char              *cp, *end;
-       u_int                    n, width = 0;
+       u_int                    n, leading_width, width = 0;
        struct utf8_data         ud;
        enum utf8_state          more;
 
        cp = expanded;
        while (*cp != '\0') {
                if (*cp == '#') {
-                       for (n = 1; cp[n] == '#'; n++)
-                               /* nothing */;
-                       if (cp[n] != '[') {
-                               width += n;
-                               cp += n;
-                               continue;
-                       }
-                       width += (n / 2); /* one for each ## */
-
-                       if ((n % 2) == 0) {
-                               /*
-                                * An even number of #s means that all #s are
-                                * escaped, so not a style.
-                                */
-                               width++; /* one for the [ */
-                               cp += (n + 1);
-                               continue;
+                       end = format_leading_hashes(cp, &n, &leading_width);
+                       width += leading_width;
+                       cp = end;
+                       if (*cp == '#') {
+                               end = format_skip(cp + 2, "]");
+                               if (end == NULL)
+                                       return (0);
+                               cp = end + 1;
                        }
-                       cp += (n - 1); /* point to the [ */
-
-                       end = format_skip(cp + 2, "]");
-                       if (end == NULL)
-                               return (0);
-                       cp = end + 1;
                } else if ((more = utf8_open(&ud, *cp)) == UTF8_MORE) {
                        while (*++cp != '\0' && more == UTF8_MORE)
                                more = utf8_append(&ud, *cp);
@@ -1059,7 +1074,7 @@ format_trim_left(const char *expanded, u_int limit)
 {
        char                    *copy, *out;
        const char              *cp = expanded, *end;
-       u_int                    even, n, width = 0;
+       u_int                    n, width = 0, leading_width;
        struct utf8_data         ud;
        enum utf8_state          more;
 
@@ -1068,44 +1083,27 @@ format_trim_left(const char *expanded, u_int limit)
                if (width >= limit)
                        break;
                if (*cp == '#') {
-                       for (end = cp + 1; *end == '#'; end++)
-                               /* nothing */;
-                       n = end - cp;
-                       if (*end != '[') {
-                               if (n > limit - width)
-                                       n = limit - width;
-                               memcpy(out, cp, n);
-                               out += n;
-                               width += n;
-                               cp = end;
-                               continue;
-                       }
-                       even = ((n % 2) == 0);
-
-                       n /= 2;
-                       if (n > limit - width)
-                               n = limit - width;
-                       width += n;
-                       n *= 2;
-                       memcpy(out, cp, n);
-                       out += n;
-
-                       if (even) {
-                               if (width + 1 <= limit) {
-                                       *out++ = '[';
-                                       width++;
+                       end = format_leading_hashes(cp, &n, &leading_width);
+                       if (leading_width > limit - width)
+                               leading_width = limit - width;
+                       if (leading_width != 0) {
+                               if (n == 1)
+                                       *out++ = '#';
+                               else {
+                                       memset(out, '#', 2 * leading_width);
+                                       out += 2 * leading_width;
                                }
+                               width += leading_width;
+                       }
+                       cp = end;
+                       if (*cp == '#') {
+                               end = format_skip(cp + 2, "]");
+                               if (end == NULL)
+                                       break;
+                               memcpy(out, cp, end + 1 - cp);
+                               out += (end + 1 - cp);
                                cp = end + 1;
-                               continue;
                        }
-                       cp = end - 1;
-
-                       end = format_skip(cp + 2, "]");
-                       if (end == NULL)
-                               break;
-                       memcpy(out, cp, end + 1 - cp);
-                       out += (end + 1 - cp);
-                       cp = end + 1;
                } else if ((more = utf8_open(&ud, *cp)) == UTF8_MORE) {
                        while (*++cp != '\0' && more == UTF8_MORE)
                                more = utf8_append(&ud, *cp);
@@ -1137,7 +1135,8 @@ format_trim_right(const char *expanded, u_int limit)
 {
        char                    *copy, *out;
        const char              *cp = expanded, *end;
-       u_int                    width = 0, total_width, skip, old_n, even, n;
+       u_int                    width = 0, total_width, skip, n;
+       u_int                    leading_width, copy_width;
        struct utf8_data         ud;
        enum utf8_state          more;
 
@@ -1149,64 +1148,32 @@ format_trim_right(const char *expanded, u_int limit)
        out = copy = xcalloc(1, strlen(expanded) + 1);
        while (*cp != '\0') {
                if (*cp == '#') {
-                       for (end = cp + 1; *end == '#'; end++)
-                               /* nothing */;
-                       old_n = n = end - cp;
-                       if (*end != '[') {
-                               if (width <= skip) {
-                                       if (skip - width >= n)
-                                               n = 0;
-                                       else
-                                               n -= (skip - width);
-                               }
-                               if (n != 0) {
-                                       memcpy(out, cp, n);
-                                       out += n;
-                               }
-
-                               /*
-                                * The width always increases by the full
-                                * amount even if we can't copy anything yet.
-                                */
-                               width += old_n;
-                               cp = end;
-                               continue;
-                       }
-                       even = ((n % 2) == 0);
-
-                       n /= 2;
+                       end = format_leading_hashes(cp, &n, &leading_width);
                        if (width <= skip) {
-                               if (skip - width >= n)
-                                       n = 0;
+                               if (skip - width >= leading_width)
+                                       copy_width = 0;
                                else
-                                       n -= (skip - width);
-                       }
-                       if (n != 0) {
-                               /*
-                                * Copy the full amount because it hasn't been
-                                * escaped yet.
-                                */
-                               memcpy(out, cp, old_n);
-                               out += old_n;
-                       }
-                       cp += old_n;
-                       width += (old_n / 2) - even;
-
-                       if (even) {
-                               if (width > skip)
-                                       *out++ = '[';
-                               width++;
-                               continue;
+                                       copy_width -= (skip - width);
+                       } else
+                               copy_width = leading_width;
+                       if (copy_width != 0) {
+                               if (n == 1)
+                                       *out++ = '#';
+                               else {
+                                       memset(out, '#', 2 * copy_width);
+                                       out += 2 * copy_width;
+                               }
                        }
-                       cp = end - 1;
-
-                       end = format_skip(cp + 2, "]");
-                       if (end == NULL) {
-                               break;
+                       width += leading_width;
+                       cp = end;
+                       if (*cp == '#') {
+                               end = format_skip(cp + 2, "]");
+                               if (end == NULL)
+                                       break;
+                               memcpy(out, cp, end + 1 - cp);
+                               out += (end + 1 - cp);
+                               cp = end + 1;
                        }
-                       memcpy(out, cp, end + 1 - cp);
-                       out += (end + 1 - cp);
-                       cp = end + 1;
                } else if ((more = utf8_open(&ud, *cp)) == UTF8_MORE) {
                        while (*++cp != '\0' && more == UTF8_MORE)
                                more = utf8_append(&ud, *cp);