Break cursor movement in grid into a common set of functions that can

handle line wrapping and so on in one place and use them for the obvious
copy mode commands. From Anindya Mukherjee.

1 files changed, 303 insertions, 0 deletions

diff --git a/usr.bin/tmux/grid-reader.c b/usr.bin/tmux/grid-reader.c
new file mode 100644
index 00000000000..6bfae499025
--- /dev/null
+++ b/usr.bin/tmux/grid-reader.c
@@ -0,0 +1,303 @@
+/* $OpenBSD: grid-reader.c,v 1.1 2020/12/22 09:22:14 nicm Exp $ */
+
+/*
+ * Copyright (c) 2020 Anindya Mukherjee <anindya49@hotmail.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
+ * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
+ * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include "tmux.h"
+
+/* Initialise virtual cursor. */
+void
+grid_reader_start(struct grid_reader *gr, struct grid *gd, u_int cx, u_int cy)
+{
+	gr->gd = gd;
+	gr->cx = cx;
+	gr->cy = cy;
+}
+
+/* Get cursor position from reader. */
+void
+grid_reader_get_cursor(struct grid_reader *gr, u_int *cx, u_int *cy)
+{
+	*cx = gr->cx;
+	*cy = gr->cy;
+}
+
+/* Get length of line containing the cursor. */
+u_int
+grid_reader_line_length(struct grid_reader *gr)
+{
+	return (grid_line_length(gr->gd, gr->cy));
+}
+
+/* Move cursor forward one position. */
+void
+grid_reader_cursor_right(struct grid_reader *gr, int wrap, int all)
+{
+	u_int			px;
+	struct grid_cell	gc;
+
+	if (all)
+		px = gr->gd->sx;
+	else
+		px = grid_reader_line_length(gr);
+
+	if (wrap && gr->cx >= px && gr->cy < gr->gd->hsize + gr->gd->sy - 1) {
+		grid_reader_cursor_start_of_line(gr, 0);
+		grid_reader_cursor_down(gr);
+	} else if (gr->cx < px) {
+		gr->cx++;
+		while (gr->cx < px) {
+			grid_get_cell(gr->gd, gr->cx, gr->cy, &gc);
+			if (~gc.flags & GRID_FLAG_PADDING)
+				break;
+			gr->cx++;
+		}
+	}
+}
+
+/* Move cursor back one position. */
+void
+grid_reader_cursor_left(struct grid_reader *gr)
+{
+	struct grid_cell	gc;
+
+	while (gr->cx > 0) {
+		grid_get_cell(gr->gd, gr->cx, gr->cy, &gc);
+		if (~gc.flags & GRID_FLAG_PADDING)
+			break;
+		gr->cx--;
+	}
+	if (gr->cx == 0 && gr->cy > 0) {
+		grid_reader_cursor_up(gr);
+		grid_reader_cursor_end_of_line(gr, 0, 0);
+	} else if (gr->cx > 0)
+		gr->cx--;
+}
+
+/* Move cursor down one line. */
+void
+grid_reader_cursor_down(struct grid_reader *gr)
+{
+	struct grid_cell	gc;
+
+	if (gr->cy < gr->gd->hsize + gr->gd->sy - 1)
+		gr->cy++;
+	while (gr->cx > 0) {
+		grid_get_cell(gr->gd, gr->cx, gr->cy, &gc);
+		if (~gc.flags & GRID_FLAG_PADDING)
+			break;
+		gr->cx--;
+	}
+}
+
+/* Move cursor up one line. */
+void
+grid_reader_cursor_up(struct grid_reader *gr)
+{
+	struct grid_cell	gc;
+
+	if (gr->cy > 0)
+		gr->cy--;
+	while (gr->cx > 0) {
+		grid_get_cell(gr->gd, gr->cx, gr->cy, &gc);
+		if (~gc.flags & GRID_FLAG_PADDING)
+			break;
+		gr->cx--;
+	}
+}
+
+/* Move cursor to the start of the line. */
+void
+grid_reader_cursor_start_of_line(struct grid_reader *gr, int wrap)
+{
+	if (wrap) {
+		while (gr->cy > 0 &&
+		    grid_get_line(gr->gd, gr->cy - 1)->flags &
+		        GRID_LINE_WRAPPED)
+			gr->cy--;
+	}
+	gr->cx = 0;
+}
+
+/* Move cursor to the end of the line. */
+void
+grid_reader_cursor_end_of_line(struct grid_reader *gr, int wrap, int all)
+{
+	u_int	yy;
+
+	if (wrap) {
+		yy = gr->gd->hsize + gr->gd->sy - 1;
+		while (gr->cy < yy && grid_get_line(gr->gd, gr->cy)->flags &
+		    GRID_LINE_WRAPPED)
+			gr->cy++;
+	}
+	if (all)
+		gr->cx = gr->gd->sx;
+	else
+		gr->cx = grid_reader_line_length(gr);
+}
+
+/* Check if character under cursor is in set. */
+int
+grid_reader_in_set(struct grid_reader *gr, const char *set)
+{
+	struct grid_cell	gc;
+
+	grid_get_cell(gr->gd, gr->cx, gr->cy, &gc);
+	if (gc.flags & GRID_FLAG_PADDING)
+		return (0);
+	return (utf8_cstrhas(set, &gc.data));
+}
+
+/* Move cursor to the start of the next word. */
+void
+grid_reader_cursor_next_word(struct grid_reader *gr, const char *separators)
+{
+	u_int	xx, yy;
+	int expected = 0;
+
+	/* Do not break up wrapped words. */
+	if (grid_get_line(gr->gd, gr->cy)->flags & GRID_LINE_WRAPPED)
+		xx = grid_reader_line_length(gr) - 1;
+	else
+		xx = grid_reader_line_length(gr);
+	yy = gr->gd->hsize + gr->gd->sy - 1;
+
+	/*
+	 * If we started inside a word, skip over word characters. Then skip
+	 * over separators till the next word.
+	 *
+	 * expected is initially set to 0 for the former and then 1 for the
+	 * latter. It is finally set to 0 when the beginning of the next word is
+	 * found.
+	 */
+	do {
+		while (gr->cx > xx ||
+		    grid_reader_in_set(gr, separators) == expected) {
+			/* Move down if we are past the end of the line. */
+			if (gr->cx > xx) {
+				if (gr->cy == yy)
+					return;
+				grid_reader_cursor_start_of_line(gr, 0);
+				grid_reader_cursor_down(gr);
+
+				if (grid_get_line(gr->gd, gr->cy)->flags &
+				    GRID_LINE_WRAPPED)
+					xx = grid_reader_line_length(gr) - 1;
+				else
+					xx = grid_reader_line_length(gr);
+			} else
+				gr->cx++;
+		}
+		expected = !expected;
+	} while (expected == 1);
+}
+
+/* Move cursor to the end of the next word. */
+void
+grid_reader_cursor_next_word_end(struct grid_reader *gr, const char *separators)
+{
+	u_int	xx, yy;
+	int	expected = 1;
+
+	/* Do not break up wrapped words. */
+	if (grid_get_line(gr->gd, gr->cy)->flags & GRID_LINE_WRAPPED)
+		xx = grid_reader_line_length(gr) - 1;
+	else
+		xx = grid_reader_line_length(gr);
+	yy = gr->gd->hsize + gr->gd->sy - 1;
+
+	/*
+	 * If we started on a separator, skip over separators. Then skip over
+	 * word characters till the next separator.
+	 *
+	 * expected is initially set to 1 for the former and then 1 for the
+	 * latter. It is finally set to 1 when the end of the next word is
+	 * found.
+	 */
+	do {
+		while (gr->cx > xx ||
+		    grid_reader_in_set(gr, separators) == expected) {
+			/* Move down if we are past the end of the line. */
+			if (gr->cx > xx) {
+				if (gr->cy == yy)
+					return;
+				grid_reader_cursor_start_of_line(gr, 0);
+				grid_reader_cursor_down(gr);
+
+				if (grid_get_line(gr->gd, gr->cy)->flags &
+				    GRID_LINE_WRAPPED)
+					xx = grid_reader_line_length(gr) - 1;
+				else
+					xx = grid_reader_line_length(gr);
+			} else
+				gr->cx++;
+		}
+		expected = !expected;
+	} while (expected == 0);
+}
+
+/* Move to the previous place where a word begins. */
+void
+grid_reader_cursor_previous_word(struct grid_reader *gr, const char *separators,
+    int already)
+{
+	int	oldx, oldy, r;
+
+	/* Move back to the previous word character. */
+	if (already || grid_reader_in_set(gr, separators)) {
+		for (;;) {
+			if (gr->cx > 0) {
+				gr->cx--;
+				if (!grid_reader_in_set(gr, separators))
+					break;
+			} else {
+				if (gr->cy == 0)
+					return;
+				grid_reader_cursor_up(gr);
+				grid_reader_cursor_end_of_line(gr, 0, 0);
+
+				/* Stop if separator at EOL. */
+				if (gr->cx > 0) {
+					oldx = gr->cx;
+					gr->cx--;
+					r = grid_reader_in_set(gr, separators);
+					gr->cx = oldx;
+					if (r)
+						break;
+				}
+			}
+		}
+	}
+
+	/* Move back to the beginning of this word. */
+	do {
+		oldx = gr->cx;
+		oldy = gr->cy;
+		if (gr->cx == 0) {
+			if (gr->cy == 0 ||
+			  ~grid_get_line(gr->gd, gr->cy - 1)->flags &
+			  GRID_LINE_WRAPPED)
+				break;
+			grid_reader_cursor_up(gr);
+			grid_reader_cursor_end_of_line(gr, 0, 0);
+		}
+		if (gr->cx > 0)
+			gr->cx--;
+	} while (!grid_reader_in_set(gr, separators));
+	gr->cx = oldx;
+	gr->cy = oldy;
+}