window-copy.c - tmux - Rivoreo Source Code Repositories

 /* $Id: window-copy.c,v 1.24 2008-06-25 07:30:08 nicm Exp $ */

 /*
  * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
  *
  * 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 <sys/types.h>

 #include <string.h>

 #include "tmux.h"

 struct screen *window_copy_init(struct window *);
 void	window_copy_free(struct window *);
 void	window_copy_resize(struct window *, u_int, u_int);
 void	window_copy_key(struct window *, struct client *, int);

 void	window_copy_redraw_lines(struct window *, u_int, u_int);
 void	window_copy_redraw_screen(struct window *);
 void	window_copy_write_line(
     	    struct window *, struct screen_write_ctx *, u_int);
 void	window_copy_write_lines(
     	    struct window *, struct screen_write_ctx *, u_int, u_int);
 void	window_copy_write_column(
     	    struct window *, struct screen_write_ctx *, u_int);
 void	window_copy_write_columns(
     	    struct window *, struct screen_write_ctx *, u_int, u_int);

 void	window_copy_update_cursor(struct window *);
 void	window_copy_start_selection(struct window *);
 int	window_copy_update_selection(struct window *);
 void	window_copy_copy_selection(struct window *, struct client *);
 void	window_copy_copy_line(
 	    struct window *, char **, size_t *, size_t *, u_int, u_int, u_int);
 u_int	window_copy_find_length(struct window *, u_int);
 void	window_copy_cursor_start_of_line(struct window *);
 void	window_copy_cursor_end_of_line(struct window *);
 void	window_copy_cursor_left(struct window *);
 void	window_copy_cursor_right(struct window *);
 void	window_copy_cursor_up(struct window *);
 void	window_copy_cursor_down(struct window *);
 void	window_copy_cursor_next_word(struct window *);
 void	window_copy_cursor_previous_word(struct window *);
 void	window_copy_scroll_left(struct window *, u_int);
 void	window_copy_scroll_right(struct window *, u_int);
 void	window_copy_scroll_up(struct window *, u_int);
 void	window_copy_scroll_down(struct window *, u_int);

 const char *space_characters = " -_@";
 #define window_copy_is_space(w, x, y) \
 	(strchr(space_characters, (w)->base.grid_data[y][x]) != NULL)

 const struct window_mode window_copy_mode = {
 	window_copy_init,
 	window_copy_free,
 	window_copy_resize,
 	window_copy_key
 };

 struct window_copy_mode_data {
 	struct screen	screen;

 	u_int	ox;
 	u_int	oy;

 	u_int	selx;
 	u_int	sely;

 	u_int	cx;
 	u_int	cy;
 };

 struct screen *
 window_copy_init(struct window *w)
 {
 	struct window_copy_mode_data	*data;
 	struct screen			*s;
 	struct screen_write_ctx	 	 ctx;
 	u_int				 i;

 	w->modedata = data = xmalloc(sizeof *data);
 	data->ox = 0;
 	data->oy = 0;
 	data->cx = w->base.cx;
 	data->cy = w->base.cy;

 	s = &data->screen;
 	screen_create(s, screen_size_x(&w->base), screen_size_y(&w->base), 0);
 	s->cx = data->cx;
 	s->cy = data->cy;

 	screen_write_start(&ctx, s, NULL, NULL);
 	for (i = 0; i < screen_size_y(s); i++)
 		window_copy_write_line(w, &ctx, i);
 	screen_write_move_cursor(&ctx, data->cx, data->cy);
 	screen_write_stop(&ctx);

 	return (s);
 }

 void
 window_copy_free(struct window *w)
 {
 	struct window_copy_mode_data	*data = w->modedata;

 	screen_destroy(&data->screen);
 	xfree(data);
 }

 void
 window_copy_resize(struct window *w, u_int sx, u_int sy)
 {
 	struct window_copy_mode_data	*data = w->modedata;
 	struct screen			*s = &data->screen;

 	screen_resize(s, sx, sy);
 	screen_display_copy_area(&data->screen, &w->base,
 	    0, 0, screen_size_x(s), screen_size_y(s), data->ox, data->oy);
 	window_copy_update_selection(w);
 }

 void
 window_copy_key(struct window *w, struct client *c, int key)
 {
 	struct window_copy_mode_data	*data = w->modedata;
 	struct screen			*s = &data->screen;

 	switch (key) {
 	case 'Q':
 	case 'q':
 		window_reset_mode(w);
 		break;
 	case 'h':
 	case KEYC_LEFT:
 		window_copy_cursor_left(w);
 		return;
 	case 'l':
 	case KEYC_RIGHT:
 		window_copy_cursor_right(w);
  		return;
 	case 'k':
 	case 'K':
 	case KEYC_UP:
 		window_copy_cursor_up(w);
 		return;
 	case 'j':
 	case 'J':
 	case KEYC_DOWN:
 		window_copy_cursor_down(w);
 		return;
 	case '\025':	/* C-u */
 	case KEYC_PPAGE:
 		if (data->oy + screen_size_y(s) > w->base.hsize)
 			data->oy = w->base.hsize;
 		else
 			data->oy += screen_size_y(s);
 		window_copy_update_selection(w);
 		window_copy_redraw_screen(w);
 		break;
 	case '\006':	/* C-f */
 	case KEYC_NPAGE:
 		if (data->oy < screen_size_y(s))
 			data->oy = 0;
 		else
 			data->oy -= screen_size_y(s);
 		window_copy_update_selection(w);
 		window_copy_redraw_screen(w);
 		break;
 	case '\000':	/* C-space */
 	case ' ':
 		window_copy_start_selection(w);
 		break;
 	case '\033':
 		screen_clear_selection(&data->screen);
 		break;
 	case '\027':	/* C-w */
  	case '\r':	/* enter */
 		if (c != NULL && c->session != NULL) {
 			window_copy_copy_selection(w, c);
 			window_reset_mode(w);
 		}
 		break;
 	case '0':
 	case '\001':	/* C-a */
 		window_copy_cursor_start_of_line(w);
 		break;
 	case '$':
 	case '\005':	/* C-e */
 		window_copy_cursor_end_of_line(w);
 		break;
 	case 'w':
 	case KEYC_ADDESCAPE('F'):	/* M-F */
 	case KEYC_ADDESCAPE('f'):	/* M-f */
 		window_copy_cursor_next_word(w);
 		break;
 	case 'b':
 	case KEYC_ADDESCAPE('B'):	/* M-B */
 	case KEYC_ADDESCAPE('b'):	/* M-b */
 		window_copy_cursor_previous_word(w);
 		break;
 	}
 }

 void
 window_copy_write_line(
     struct window *w, struct screen_write_ctx *ctx, u_int py)
 {
 	struct window_copy_mode_data	*data = w->modedata;
 	struct screen			*s = &data->screen;
 	size_t	 			 size;

 	if (py == 0) {
 		screen_write_set_attributes(
 		    ctx, ATTR_BRIGHT|ATTR_REVERSE, 0x88);
 		screen_write_move_cursor(ctx, 0, 0);
 		size = screen_write_put_string_rjust(
 		    ctx, "[%u,%u/%u]", data->ox, data->oy, w->base.hsize);
 		screen_write_set_attributes(
 		    ctx, SCREEN_DEFATTR, SCREEN_DEFCOLR);
 	} else
 		size = 0;
 	screen_write_move_cursor(ctx, 0, py);
 	screen_write_copy_area(
 	    ctx, &w->base, screen_size_x(s) - size, 1, data->ox, data->oy);
 }

 void
 window_copy_write_lines(
     struct window *w, struct screen_write_ctx *ctx, u_int py, u_int ny)
 {
 	struct window_copy_mode_data	*data = w->modedata;
 	struct screen			*s = &data->screen;

 	if (py == 0) {
 		window_copy_write_line(w, ctx, 0);
 		if (ny == 1)
 			return;
 		py++;
 		ny--;
 	}
 	screen_write_move_cursor(ctx, 0, py);
 	screen_write_copy_area(
 	    ctx, &w->base, screen_size_x(s), ny, data->ox, data->oy);
 }

 void
 window_copy_write_column(
     struct window *w, struct screen_write_ctx *ctx, u_int px)
 {
 	struct window_copy_mode_data	*data = w->modedata;
 	struct screen			*s = &data->screen;

 	screen_write_move_cursor(ctx, px, 0);
 	screen_write_copy_area(
 	    ctx, &w->base, 1, screen_size_y(s), data->ox, data->oy);
 }

 void
 window_copy_write_columns(
     struct window *w, struct screen_write_ctx *ctx, u_int px, u_int nx)
 {
 	struct window_copy_mode_data	*data = w->modedata;
 	struct screen			*s = &data->screen;

 	screen_write_move_cursor(ctx, px, 0);
 	screen_write_copy_area(
 	    ctx, &w->base, nx, screen_size_y(s), data->ox, data->oy);
 }

 void
 window_copy_redraw_lines(struct window *w, u_int py, u_int ny)
 {
 	struct window_copy_mode_data	*data = w->modedata;
 	struct screen_write_ctx	 	 ctx;
 	u_int				 i;

 	screen_write_start_window(&ctx, w);
 	for (i = py; i < py + ny; i++)
 		window_copy_write_line(w, &ctx, i);
 	screen_write_move_cursor(&ctx, data->cx, data->cy);
 	screen_write_stop(&ctx);
 }

 void
 window_copy_redraw_screen(struct window *w)
 {
 	struct window_copy_mode_data	*data = w->modedata;

 	window_copy_redraw_lines(w, 0, screen_size_x(&data->screen));
 }

 void
 window_copy_update_cursor(struct window *w)
 {
 	struct window_copy_mode_data	*data = w->modedata;
 	struct screen_write_ctx		 ctx;

 	screen_write_start_window(&ctx, w);
 	screen_write_move_cursor(&ctx, data->cx, data->cy);
 	screen_write_stop(&ctx);
 }

 void
 window_copy_start_selection(struct window *w)
 {
 	struct window_copy_mode_data	*data = w->modedata;
 	struct screen			*s = &data->screen;

 	data->selx = screen_x(&w->base, data->cx) + data->ox;
 	data->sely = screen_y(&w->base, data->cy) - data->oy;

 	s->sel.flag = 1;
 	window_copy_update_selection(w);
 }

 int
 window_copy_update_selection(struct window *w)
 {
 	struct window_copy_mode_data	*data = w->modedata;
 	struct screen			*s = &data->screen;
 	u_int				 sx, sy, tx, ty;

 	if (!s->sel.flag)
 		return (0);

 	/* Find top-left of screen. */
 	tx = screen_x(&w->base, 0) + data->ox;
 	ty = screen_y(&w->base, 0) - data->oy;

 	/* Adjust the selection. */
 	sx = data->selx;
 	sy = data->sely;
 	if (sy < ty) {
 		/* Above it. */
 		sx = 0;
 		sy = 0;
 	} else if (sy > ty + screen_last_y(s)) {
 		/* Below it. */
 		sx = screen_last_x(s);
 		sy = screen_last_y(s);
 	} else if (sx < tx) {
 		/* To the left. */
 		sx = 0;
 	} else if (sx > tx + screen_last_x(s)) {
 		/* To the right. */
 		sx = 0;
 		sy++;
 		if (sy > screen_last_y(s))
 			sy = screen_last_y(s);
 	} else {
 		sx -= tx;
 		sy -= ty;
 	}
 	sx = screen_x(s, sx);
 	sy = screen_x(s, sy);

 	screen_set_selection(
 	    s, sx, sy, screen_x(s, data->cx), screen_y(s, data->cy));
 	return (1);
 }

 void
 window_copy_copy_selection(struct window *w, struct client *c)
 {
 	struct window_copy_mode_data	*data = w->modedata;
 	struct screen			*s = &data->screen;
 	char				*buf;
 	size_t	 			 len, off;
 	u_int	 			 i, xx, yy, sx, sy, ex, ey, limit;

 	if (!s->sel.flag)
 		return;

 	len = BUFSIZ;
 	buf = xmalloc(len);
 	off = 0;

 	*buf = '\0';

 	/*
 	 * The selection extends from selx,sely to (adjusted) cx,cy on
 	 * the base screen.
 	 */

 	/* Find start and end. */
 	xx = screen_x(&w->base, data->cx) + data->ox;
 	yy = screen_y(&w->base, data->cy) - data->oy;
 	if (xx < data->selx || (yy == data->sely && xx < data->selx)) {
 		sx = xx; sy = yy;
 		ex = data->selx; ey = data->sely;
 	} else {
 		sx = data->selx; sy = data->sely;
 		ex = xx; ey = yy;
 	}

 	/* Trim ex to end of line. */
 	xx = window_copy_find_length(w, ey);
 	if (ex > xx)
 		ex = xx;

 	/* Copy the lines. */
 	if (sy == ey)
 		window_copy_copy_line(w, &buf, &off, &len, sy, sx, ex);
 	else {
 		xx = window_copy_find_length(w, sy);
 		window_copy_copy_line(w, &buf, &off, &len, sy, sx, xx);
 		if (ey - sy > 1) {
 			for (i = sy + 1; i < ey - 1; i++) {
 				xx = window_copy_find_length(w, i);
 				window_copy_copy_line(
 				    w, &buf, &off, &len, i, 0, xx);
 			}
 		}
 		window_copy_copy_line(w, &buf, &off, &len, ey, 0, ex);
 	}

 	/* Terminate buffer, overwriting final \n. */
 	if (off != 0)
 		buf[off - 1] = '\0';

 	/* Add the buffer to the stack. */
 	limit = options_get_number(&c->session->options, "buffer-limit");
 	paste_add(&c->session->buffers, buf, limit);
 	xfree(buf);
 }

 void
 window_copy_copy_line(struct window *w,
     char **buf, size_t *off, size_t *len, u_int sy, u_int sx, u_int ex)
 {
 	u_char	i, xx;

 	if (sx > ex)
 		return;

 	xx = window_copy_find_length(w, sy);
 	if (ex > xx)
 		ex = xx;
 	if (sx > xx)
 		sx = xx;

 	if (sx < ex) {
 		for (i = sx; i < ex; i++) {
 			*buf = ensure_size(*buf, len, 1, *off + 1);
 			(*buf)[*off] = w->base.grid_data[sy][i];
 			(*off)++;
 		}
 	}

 	*buf = ensure_size(*buf, len, 1, *off + 1);
 	(*buf)[*off] = '\n';
 	(*off)++;
 }

 u_int
 window_copy_find_length(struct window *w, u_int py)
 {
 	u_int	px;

 	px = w->base.grid_size[py];
 	while (px > 0 && w->base.grid_data[py][px - 1] == SCREEN_DEFDATA)
 		px--;
 	return (px);
 }

 void
 window_copy_cursor_start_of_line(struct window *w)
 {
 	struct window_copy_mode_data	*data = w->modedata;

 	if (data->ox != 0)
 		window_copy_scroll_right(w, data->ox);
 	data->cx = 0;

 	if (window_copy_update_selection(w))
 		window_copy_redraw_lines(w, data->cy, 1);
 	else
 		window_copy_update_cursor(w);
 }

 void
 window_copy_cursor_end_of_line(struct window *w)
 {
 	struct window_copy_mode_data	*data = w->modedata;
 	struct screen			*s = &data->screen;
 	u_int				 px, py;

 	py = screen_y(&w->base, data->cy) - data->oy;
 	px = window_copy_find_length(w, py);

 	/* On screen. */
 	if (px > data->ox && px <= data->ox + screen_last_x(s))
 		data->cx = px - data->ox;

 	/* Off right of screen. */
 	if (px > data->ox + screen_last_x(s)) {
 		/* Move cursor to last and scroll screen. */
 		window_copy_scroll_left(w,
 		    px - data->ox - screen_last_x(s));
 		data->cx = screen_last_x(s);
 	}

 	/* Off left of screen. */
 	if (px <= data->ox) {
 		if (px < screen_last_x(s)) {
 			/* Short enough to fit on screen. */
 			window_copy_scroll_right(w, data->ox);
 			data->cx = px;
 		} else {
 			/* Too long to fit on screen. */
 			window_copy_scroll_right(
 			    w, data->ox - (px - screen_last_x(s)));
 			data->cx = screen_last_x(s);
 		}
  	}

 	if (window_copy_update_selection(w))
 		window_copy_redraw_lines(w, data->cy, 1);
 	else
 		window_copy_update_cursor(w);
 }

 void
 window_copy_cursor_left(struct window *w)
 {
 	struct window_copy_mode_data	*data = w->modedata;

 	if (data->cx == 0) {
 		if (data->ox > 0)
 			window_copy_scroll_right(w, 1);
 		else {
 			window_copy_cursor_up(w);
 			window_copy_cursor_end_of_line(w);
 		}
 	} else {
 		data->cx--;
 		if (window_copy_update_selection(w))
 			window_copy_redraw_lines(w, data->cy, 1);
 		else
 			window_copy_update_cursor(w);
 	}
 }

 void
 window_copy_cursor_right(struct window *w)
 {
 	struct window_copy_mode_data	*data = w->modedata;
 	u_int				 px, py;

 	py = screen_y(&w->base, data->cy) - data->oy;
 	px = window_copy_find_length(w, py);

 	if (data->cx >= px) {
 		window_copy_cursor_start_of_line(w);
 		window_copy_cursor_down(w);
 	} else {
 		data->cx++;
 		if (window_copy_update_selection(w))
 			window_copy_redraw_lines(w, data->cy, 1);
 		else
 			window_copy_update_cursor(w);
 	}
 }

 void
 window_copy_cursor_up(struct window *w)
 {
 	struct window_copy_mode_data	*data = w->modedata;
 	u_int				 ox, oy, px, py;

 	oy = screen_y(&w->base, data->cy) - data->oy;
 	ox = window_copy_find_length(w, oy);

 	if (data->cy == 0)
 		window_copy_scroll_down(w, 1);
 	else {
 		data->cy--;
 		if (window_copy_update_selection(w))
 			window_copy_redraw_lines(w, data->cy, 2);
 		else
 			window_copy_update_cursor(w);
 	}

 	py = screen_y(&w->base, data->cy) - data->oy;
 	px = window_copy_find_length(w, py);

 	if (data->cx + data->ox >= px || data->cx + data->ox >= ox)
 		window_copy_cursor_end_of_line(w);
 }

 void
 window_copy_cursor_down(struct window *w)
 {
 	struct window_copy_mode_data	*data = w->modedata;
 	struct screen			*s = &data->screen;
 	u_int				 ox, oy, px, py;

 	oy = screen_y(&w->base, data->cy) - data->oy;
 	ox = window_copy_find_length(w, oy);

 	if (data->cy == screen_last_y(s))
 		window_copy_scroll_up(w, 1);
 	else {
 		data->cy++;
 		if (window_copy_update_selection(w))
 			window_copy_redraw_lines(w, data->cy - 1, 2);
 		else
 			window_copy_update_cursor(w);
 	}

 	py = screen_y(&w->base, data->cy) - data->oy;
 	px = window_copy_find_length(w, py);

 	if (data->cx + data->ox >= px || data->cx + data->ox >= ox)
 		window_copy_cursor_end_of_line(w);
 }

 void
 window_copy_cursor_next_word(struct window *w)
 {
 	struct window_copy_mode_data	*data = w->modedata;
 	struct screen			*s = &data->screen;
 	u_int				 px, py, xx, skip;

 	px = data->ox + data->cx;
 	py = screen_y(&w->base, data->cy) - data->oy;
 	xx = window_copy_find_length(w, py);

 	skip = 1;
 	if (px < xx) {
 		/* If currently on a space, skip space. */
 		if (window_copy_is_space(w, px, py))
 			skip = 0;
 	} else
 		skip = 0;
 	for (;;) {
 		if (px >= xx) {
 			if (skip) {
 				px = xx;
 				break;
 			}

 			while (px >= xx) {
 				if (data->cy == screen_last_y(s)) {
 					if (data->oy == 0)
 						goto out;
 				}

 				px = 0;
 				window_copy_cursor_down(w);

 				py = screen_y(&w->base, data->cy) - data->oy;
 				xx = window_copy_find_length(w, py);
 			}
 		}

 		if (skip) {
 			/* Currently skipping non-space (until space). */
 			if (window_copy_is_space(w, px, py))
 				break;
 		} else {
 			/* Currently skipping space (until non-space). */
 			if (!window_copy_is_space(w, px, py))
 				skip = 1;
 		}

 		px++;
 	}
 out:

 	/* On screen. */
 	if (px > data->ox && px <= data->ox + screen_last_x(s))
 		data->cx = px - data->ox;

 	/* Off right of screen. */
 	if (px > data->ox + screen_last_x(s)) {
 		/* Move cursor to last and scroll screen. */
 		window_copy_scroll_left(w,
 		    px - data->ox - screen_last_x(s));
 		data->cx = screen_last_x(s);
 	}

 	/* Off left of screen. */
 	if (px <= data->ox) {
 		if (px < screen_last_x(s)) {
 			/* Short enough to fit on screen. */
 			window_copy_scroll_right(w, data->ox);
 			data->cx = px;
 		} else {
 			/* Too long to fit on screen. */
 			window_copy_scroll_right(
 			    w, data->ox - (px - screen_last_x(s)));
 			data->cx = screen_last_x(s);
 		}
  	}

 	if (window_copy_update_selection(w))
 		window_copy_redraw_lines(w, data->cy, 1);
 	else
 		window_copy_update_cursor(w);
 }

 void
 window_copy_cursor_previous_word(struct window *w)
 {
 	struct window_copy_mode_data	*data = w->modedata;
 	struct screen			*s = &data->screen;
 	u_int				 px, py, skip;

 	px = data->ox + data->cx;
 	py = screen_y(&w->base, data->cy) - data->oy;

 	skip = 1;
 	if (px != 0) {
 		/* If currently on a space, skip space. */
 		if (window_copy_is_space(w, px - 1, py))
 			skip = 0;
 	}
 	for (;;) {
 		while (px == 0) {
 			if (data->cy == 0) {
 				if (w->base.hsize == 0 ||
 				    data->oy >= w->base.hsize - 1)
 					goto out;
 			}

 			window_copy_cursor_up(w);

 			py = screen_y(&w->base, data->cy) - data->oy;
 			px = window_copy_find_length(w, py);
 			if (px != 0)
 				goto out;
 		}

 		if (skip) {
 			/* Currently skipping non-space (until space). */
 			if (window_copy_is_space(w, px - 1, py))
 				skip = 0;
 		} else {
 			/* Currently skipping space (until non-space). */
 			if (!window_copy_is_space(w, px - 1, py))
 				break;
 		}

 		px--;
 	}
 out:

 	/* On screen. */
 	if (px > data->ox && px <= data->ox + screen_last_x(s))
 		data->cx = px - data->ox;

 	/* Off right of screen. */
 	if (px > data->ox + screen_last_x(s)) {
 		/* Move cursor to last and scroll screen. */
 		window_copy_scroll_left(w,
 		    px - data->ox - screen_last_x(s));
 		data->cx = screen_last_x(s);
 	}

 	/* Off left of screen. */
 	if (px <= data->ox) {
 		if (px < screen_last_x(s)) {
 			/* Short enough to fit on screen. */
 			window_copy_scroll_right(w, data->ox);
 			data->cx = px;
 		} else {
 			/* Too long to fit on screen. */
 			window_copy_scroll_right(
 			    w, data->ox - (px - screen_last_x(s)));
 			data->cx = screen_last_x(s);
 		}
  	}

 	if (window_copy_update_selection(w))
 		window_copy_redraw_lines(w, data->cy, 1);
 	else
 		window_copy_update_cursor(w);
 }

 void
 window_copy_scroll_left(struct window *w, u_int nx)
 {
 	struct window_copy_mode_data	*data = w->modedata;
 	struct screen			*s = &data->screen;
 	struct screen_write_ctx		 ctx;
 	u_int				 i;

 	if (data->ox > SHRT_MAX - nx)
 		nx = SHRT_MAX - data->ox;
 	if (nx == 0)
 		return;
 	data->ox += nx;
 	window_copy_update_selection(w);

 	screen_write_start_window(&ctx, w);
 	for (i = 1; i < screen_size_y(s); i++) {
 		screen_write_move_cursor(&ctx, 0, i);
 		screen_write_delete_characters(&ctx, nx);
 	}
 	window_copy_write_columns(w, &ctx, screen_size_x(s) - nx, nx);
 	window_copy_write_line(w, &ctx, 0);
 	if (s->sel.flag) {
 		window_copy_update_selection(w);
 		window_copy_write_lines(w, &ctx, data->cy, 1);
 	}
 	screen_write_move_cursor(&ctx, data->cx, data->cy);
 	screen_write_stop(&ctx);
 }

 void
 window_copy_scroll_right(struct window *w, u_int nx)
 {
 	struct window_copy_mode_data	*data = w->modedata;
 	struct screen			*s = &data->screen;
 	struct screen_write_ctx		 ctx;
 	u_int		 		 i;

 	if (data->ox < nx)
 		nx = data->ox;
 	if (nx == 0)
 		return;
 	data->ox -= nx;
 	window_copy_update_selection(w);

 	screen_write_start_window(&ctx, w);
 	for (i = 1; i < screen_size_y(s); i++) {
 		screen_write_move_cursor(&ctx, 0, i);
 		screen_write_insert_characters(&ctx, nx);
 	}
 	window_copy_write_columns(w, &ctx, 0, nx);
 	window_copy_write_line(w, &ctx, 0);
 	if (s->sel.flag)
 		window_copy_write_lines(w, &ctx, data->cy, 1);
 	screen_write_move_cursor(&ctx, data->cx, data->cy);
 	screen_write_stop(&ctx);
 }

 void
 window_copy_scroll_up(struct window *w, u_int ny)
 {
 	struct window_copy_mode_data	*data = w->modedata;
 	struct screen			*s = &data->screen;
 	struct screen_write_ctx		 ctx;

 	if (data->oy < ny)
 		ny = data->oy;
 	if (ny == 0)
 		return;
 	data->oy -= ny;
 	window_copy_update_selection(w);

 	screen_write_start_window(&ctx, w);
 	screen_write_move_cursor(&ctx, 0, 0);
 	screen_write_delete_lines(&ctx, ny);
 	window_copy_write_lines(w, &ctx, screen_size_y(s) - ny, ny);
 	window_copy_write_line(w, &ctx, 0);
 	if (s->sel.flag && screen_size_y(s) > ny)
 		window_copy_write_lines(w, &ctx, screen_size_y(s) - ny - 1, 1);
 	screen_write_move_cursor(&ctx, data->cx, data->cy);
 	screen_write_stop(&ctx);
 }

 void
 window_copy_scroll_down(struct window *w, u_int ny)
 {
 	struct window_copy_mode_data	*data = w->modedata;
 	struct screen			*s = &data->screen;
 	struct screen_write_ctx		 ctx;

 	if (ny > w->base.hsize)
 		return;

 	if (data->oy > w->base.hsize - ny)
 		ny = w->base.hsize - data->oy;
 	if (ny == 0)
 		return;
 	data->oy += ny;
 	window_copy_update_selection(w);

 	screen_write_start_window(&ctx, w);
 	screen_write_move_cursor(&ctx, 0, 0);
 	screen_write_insert_lines(&ctx, ny);
 	window_copy_write_lines(w, &ctx, 0, ny);
 	if (s->sel.flag && screen_size_y(s) > ny)
 		window_copy_write_lines(w, &ctx, ny, 1);
 	else if (ny == 1) /* nuke position */
 		window_copy_write_line(w, &ctx, 1);
 	screen_write_move_cursor(&ctx, data->cx, data->cy);
 	screen_write_stop(&ctx);
 }
	/* $Id: window-copy.c,v 1.24 2008-06-25 07:30:08 nicm Exp $ */

	/*
	* Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
	*
	* 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 <sys/types.h>

	#include <string.h>

	#include "tmux.h"

	struct screen window_copy_init(struct window );
	void window_copy_free(struct window *);
	void window_copy_resize(struct window *, u_int, u_int);
	void window_copy_key(struct window , struct client , int);

	void window_copy_redraw_lines(struct window *, u_int, u_int);
	void window_copy_redraw_screen(struct window *);
	void window_copy_write_line(
	struct window , struct screen_write_ctx , u_int);
	void window_copy_write_lines(
	struct window , struct screen_write_ctx , u_int, u_int);
	void window_copy_write_column(
	struct window , struct screen_write_ctx , u_int);
	void window_copy_write_columns(
	struct window , struct screen_write_ctx , u_int, u_int);

	void window_copy_update_cursor(struct window *);
	void window_copy_start_selection(struct window *);
	int window_copy_update_selection(struct window *);
	void window_copy_copy_selection(struct window , struct client );
	void window_copy_copy_line(
	struct window , char , size_t , size_t *, u_int, u_int, u_int);
	u_int window_copy_find_length(struct window *, u_int);
	void window_copy_cursor_start_of_line(struct window *);
	void window_copy_cursor_end_of_line(struct window *);
	void window_copy_cursor_left(struct window *);
	void window_copy_cursor_right(struct window *);
	void window_copy_cursor_up(struct window *);
	void window_copy_cursor_down(struct window *);
	void window_copy_cursor_next_word(struct window *);
	void window_copy_cursor_previous_word(struct window *);
	void window_copy_scroll_left(struct window *, u_int);
	void window_copy_scroll_right(struct window *, u_int);
	void window_copy_scroll_up(struct window *, u_int);
	void window_copy_scroll_down(struct window *, u_int);

	const char *space_characters = " -_@";
	#define window_copy_is_space(w, x, y) \
	(strchr(space_characters, (w)->base.grid_data[y][x]) != NULL)

	const struct window_mode window_copy_mode = {
	window_copy_init,
	window_copy_free,
	window_copy_resize,
	window_copy_key
	};

	struct window_copy_mode_data {
	struct screen screen;

	u_int ox;
	u_int oy;

	u_int selx;
	u_int sely;

	u_int cx;
	u_int cy;
	};

	struct screen *
	window_copy_init(struct window *w)
	{
	struct window_copy_mode_data *data;
	struct screen *s;
	struct screen_write_ctx ctx;
	u_int i;

	w->modedata = data = xmalloc(sizeof *data);
	data->ox = 0;
	data->oy = 0;
	data->cx = w->base.cx;
	data->cy = w->base.cy;

	s = &data->screen;
	screen_create(s, screen_size_x(&w->base), screen_size_y(&w->base), 0);
	s->cx = data->cx;
	s->cy = data->cy;

	screen_write_start(&ctx, s, NULL, NULL);
	for (i = 0; i < screen_size_y(s); i++)
	window_copy_write_line(w, &ctx, i);
	screen_write_move_cursor(&ctx, data->cx, data->cy);
	screen_write_stop(&ctx);

	return (s);
	}

	void
	window_copy_free(struct window *w)
	{
	struct window_copy_mode_data *data = w->modedata;

	screen_destroy(&data->screen);
	xfree(data);
	}

	void
	window_copy_resize(struct window *w, u_int sx, u_int sy)
	{
	struct window_copy_mode_data *data = w->modedata;
	struct screen *s = &data->screen;

	screen_resize(s, sx, sy);
	screen_display_copy_area(&data->screen, &w->base,
	0, 0, screen_size_x(s), screen_size_y(s), data->ox, data->oy);
	window_copy_update_selection(w);
	}

	void
	window_copy_key(struct window w, struct client c, int key)
	{
	struct window_copy_mode_data *data = w->modedata;
	struct screen *s = &data->screen;

	switch (key) {
	case 'Q':
	case 'q':
	window_reset_mode(w);
	break;
	case 'h':
	case KEYC_LEFT:
	window_copy_cursor_left(w);
	return;
	case 'l':
	case KEYC_RIGHT:
	window_copy_cursor_right(w);
	return;
	case 'k':
	case 'K':
	case KEYC_UP:
	window_copy_cursor_up(w);
	return;
	case 'j':
	case 'J':
	case KEYC_DOWN:
	window_copy_cursor_down(w);
	return;
	case '\025': /* C-u */
	case KEYC_PPAGE:
	if (data->oy + screen_size_y(s) > w->base.hsize)
	data->oy = w->base.hsize;
	else
	data->oy += screen_size_y(s);
	window_copy_update_selection(w);
	window_copy_redraw_screen(w);
	break;
	case '\006': /* C-f */
	case KEYC_NPAGE:
	if (data->oy < screen_size_y(s))
	data->oy = 0;
	else
	data->oy -= screen_size_y(s);
	window_copy_update_selection(w);
	window_copy_redraw_screen(w);
	break;
	case '\000': /* C-space */
	case ' ':
	window_copy_start_selection(w);
	break;
	case '\033':
	screen_clear_selection(&data->screen);
	break;
	case '\027': /* C-w */
	case '\r': /* enter */
	if (c != NULL && c->session != NULL) {
	window_copy_copy_selection(w, c);
	window_reset_mode(w);
	}
	break;
	case '0':
	case '\001': /* C-a */
	window_copy_cursor_start_of_line(w);
	break;
	case '$':
	case '\005': /* C-e */
	window_copy_cursor_end_of_line(w);
	break;
	case 'w':
	case KEYC_ADDESCAPE('F'): /* M-F */
	case KEYC_ADDESCAPE('f'): /* M-f */
	window_copy_cursor_next_word(w);
	break;
	case 'b':
	case KEYC_ADDESCAPE('B'): /* M-B */
	case KEYC_ADDESCAPE('b'): /* M-b */
	window_copy_cursor_previous_word(w);
	break;
	}
	}

	void
	window_copy_write_line(
	struct window w, struct screen_write_ctx ctx, u_int py)
	{
	struct window_copy_mode_data *data = w->modedata;
	struct screen *s = &data->screen;
	size_t size;

	if (py == 0) {
	screen_write_set_attributes(
	ctx, ATTR_BRIGHT\|ATTR_REVERSE, 0x88);
	screen_write_move_cursor(ctx, 0, 0);
	size = screen_write_put_string_rjust(
	ctx, "[%u,%u/%u]", data->ox, data->oy, w->base.hsize);
	screen_write_set_attributes(
	ctx, SCREEN_DEFATTR, SCREEN_DEFCOLR);
	} else
	size = 0;
	screen_write_move_cursor(ctx, 0, py);
	screen_write_copy_area(
	ctx, &w->base, screen_size_x(s) - size, 1, data->ox, data->oy);
	}

	void
	window_copy_write_lines(
	struct window w, struct screen_write_ctx ctx, u_int py, u_int ny)
	{
	struct window_copy_mode_data *data = w->modedata;
	struct screen *s = &data->screen;

	if (py == 0) {
	window_copy_write_line(w, ctx, 0);
	if (ny == 1)
	return;
	py++;
	ny--;
	}
	screen_write_move_cursor(ctx, 0, py);
	screen_write_copy_area(
	ctx, &w->base, screen_size_x(s), ny, data->ox, data->oy);
	}

	void
	window_copy_write_column(
	struct window w, struct screen_write_ctx ctx, u_int px)
	{
	struct window_copy_mode_data *data = w->modedata;
	struct screen *s = &data->screen;

	screen_write_move_cursor(ctx, px, 0);
	screen_write_copy_area(
	ctx, &w->base, 1, screen_size_y(s), data->ox, data->oy);
	}

	void
	window_copy_write_columns(
	struct window w, struct screen_write_ctx ctx, u_int px, u_int nx)
	{
	struct window_copy_mode_data *data = w->modedata;
	struct screen *s = &data->screen;

	screen_write_move_cursor(ctx, px, 0);
	screen_write_copy_area(
	ctx, &w->base, nx, screen_size_y(s), data->ox, data->oy);
	}

	void
	window_copy_redraw_lines(struct window *w, u_int py, u_int ny)
	{
	struct window_copy_mode_data *data = w->modedata;
	struct screen_write_ctx ctx;
	u_int i;

	screen_write_start_window(&ctx, w);
	for (i = py; i < py + ny; i++)
	window_copy_write_line(w, &ctx, i);
	screen_write_move_cursor(&ctx, data->cx, data->cy);
	screen_write_stop(&ctx);
	}

	void
	window_copy_redraw_screen(struct window *w)
	{
	struct window_copy_mode_data *data = w->modedata;

	window_copy_redraw_lines(w, 0, screen_size_x(&data->screen));
	}

	void
	window_copy_update_cursor(struct window *w)
	{
	struct window_copy_mode_data *data = w->modedata;
	struct screen_write_ctx ctx;

	screen_write_start_window(&ctx, w);
	screen_write_move_cursor(&ctx, data->cx, data->cy);
	screen_write_stop(&ctx);
	}

	void
	window_copy_start_selection(struct window *w)
	{
	struct window_copy_mode_data *data = w->modedata;
	struct screen *s = &data->screen;

	data->selx = screen_x(&w->base, data->cx) + data->ox;
	data->sely = screen_y(&w->base, data->cy) - data->oy;

	s->sel.flag = 1;
	window_copy_update_selection(w);
	}

	int
	window_copy_update_selection(struct window *w)
	{
	struct window_copy_mode_data *data = w->modedata;
	struct screen *s = &data->screen;
	u_int sx, sy, tx, ty;

	if (!s->sel.flag)
	return (0);

	/* Find top-left of screen. */
	tx = screen_x(&w->base, 0) + data->ox;
	ty = screen_y(&w->base, 0) - data->oy;

	/* Adjust the selection. */
	sx = data->selx;
	sy = data->sely;
	if (sy < ty) {
	/* Above it. */
	sx = 0;
	sy = 0;
	} else if (sy > ty + screen_last_y(s)) {
	/* Below it. */
	sx = screen_last_x(s);
	sy = screen_last_y(s);
	} else if (sx < tx) {
	/* To the left. */
	sx = 0;
	} else if (sx > tx + screen_last_x(s)) {
	/* To the right. */
	sx = 0;
	sy++;
	if (sy > screen_last_y(s))
	sy = screen_last_y(s);
	} else {
	sx -= tx;
	sy -= ty;
	}
	sx = screen_x(s, sx);
	sy = screen_x(s, sy);

	screen_set_selection(
	s, sx, sy, screen_x(s, data->cx), screen_y(s, data->cy));
	return (1);
	}

	void
	window_copy_copy_selection(struct window w, struct client c)
	{
	struct window_copy_mode_data *data = w->modedata;
	struct screen *s = &data->screen;
	char *buf;
	size_t len, off;
	u_int i, xx, yy, sx, sy, ex, ey, limit;

	if (!s->sel.flag)
	return;

	len = BUFSIZ;
	buf = xmalloc(len);
	off = 0;

	*buf = '\0';

	/*
	* The selection extends from selx,sely to (adjusted) cx,cy on
	* the base screen.
	*/

	/* Find start and end. */
	xx = screen_x(&w->base, data->cx) + data->ox;
	yy = screen_y(&w->base, data->cy) - data->oy;
	if (xx < data->selx \|\| (yy == data->sely && xx < data->selx)) {
	sx = xx; sy = yy;
	ex = data->selx; ey = data->sely;
	} else {
	sx = data->selx; sy = data->sely;
	ex = xx; ey = yy;
	}

	/* Trim ex to end of line. */
	xx = window_copy_find_length(w, ey);
	if (ex > xx)
	ex = xx;

	/* Copy the lines. */
	if (sy == ey)
	window_copy_copy_line(w, &buf, &off, &len, sy, sx, ex);
	else {
	xx = window_copy_find_length(w, sy);
	window_copy_copy_line(w, &buf, &off, &len, sy, sx, xx);
	if (ey - sy > 1) {
	for (i = sy + 1; i < ey - 1; i++) {
	xx = window_copy_find_length(w, i);
	window_copy_copy_line(
	w, &buf, &off, &len, i, 0, xx);
	}
	}
	window_copy_copy_line(w, &buf, &off, &len, ey, 0, ex);
	}

	/* Terminate buffer, overwriting final \n. */
	if (off != 0)
	buf[off - 1] = '\0';

	/* Add the buffer to the stack. */
	limit = options_get_number(&c->session->options, "buffer-limit");
	paste_add(&c->session->buffers, buf, limit);
	xfree(buf);
	}

	void
	window_copy_copy_line(struct window *w,
	char *buf, size_t off, size_t *len, u_int sy, u_int sx, u_int ex)
	{
	u_char i, xx;

	if (sx > ex)
	return;

	xx = window_copy_find_length(w, sy);
	if (ex > xx)
	ex = xx;
	if (sx > xx)
	sx = xx;

	if (sx < ex) {
	for (i = sx; i < ex; i++) {
	buf = ensure_size(buf, len, 1, *off + 1);
	(buf)[off] = w->base.grid_data[sy][i];
	(*off)++;
	}
	}

	buf = ensure_size(buf, len, 1, *off + 1);
	(buf)[off] = '\n';
	(*off)++;
	}

	u_int
	window_copy_find_length(struct window *w, u_int py)
	{
	u_int px;

	px = w->base.grid_size[py];
	while (px > 0 && w->base.grid_data[py][px - 1] == SCREEN_DEFDATA)
	px--;
	return (px);
	}

	void
	window_copy_cursor_start_of_line(struct window *w)
	{
	struct window_copy_mode_data *data = w->modedata;

	if (data->ox != 0)
	window_copy_scroll_right(w, data->ox);
	data->cx = 0;

	if (window_copy_update_selection(w))
	window_copy_redraw_lines(w, data->cy, 1);
	else
	window_copy_update_cursor(w);
	}

	void
	window_copy_cursor_end_of_line(struct window *w)
	{
	struct window_copy_mode_data *data = w->modedata;
	struct screen *s = &data->screen;
	u_int px, py;

	py = screen_y(&w->base, data->cy) - data->oy;
	px = window_copy_find_length(w, py);

	/* On screen. */
	if (px > data->ox && px <= data->ox + screen_last_x(s))
	data->cx = px - data->ox;

	/* Off right of screen. */
	if (px > data->ox + screen_last_x(s)) {
	/* Move cursor to last and scroll screen. */
	window_copy_scroll_left(w,
	px - data->ox - screen_last_x(s));
	data->cx = screen_last_x(s);
	}

	/* Off left of screen. */
	if (px <= data->ox) {
	if (px < screen_last_x(s)) {
	/* Short enough to fit on screen. */
	window_copy_scroll_right(w, data->ox);
	data->cx = px;
	} else {
	/* Too long to fit on screen. */
	window_copy_scroll_right(
	w, data->ox - (px - screen_last_x(s)));
	data->cx = screen_last_x(s);
	}
	}

	if (window_copy_update_selection(w))
	window_copy_redraw_lines(w, data->cy, 1);
	else
	window_copy_update_cursor(w);
	}

	void
	window_copy_cursor_left(struct window *w)
	{
	struct window_copy_mode_data *data = w->modedata;

	if (data->cx == 0) {
	if (data->ox > 0)
	window_copy_scroll_right(w, 1);
	else {
	window_copy_cursor_up(w);
	window_copy_cursor_end_of_line(w);
	}
	} else {
	data->cx--;
	if (window_copy_update_selection(w))
	window_copy_redraw_lines(w, data->cy, 1);
	else
	window_copy_update_cursor(w);
	}
	}

	void
	window_copy_cursor_right(struct window *w)
	{
	struct window_copy_mode_data *data = w->modedata;
	u_int px, py;

	py = screen_y(&w->base, data->cy) - data->oy;
	px = window_copy_find_length(w, py);

	if (data->cx >= px) {
	window_copy_cursor_start_of_line(w);
	window_copy_cursor_down(w);
	} else {
	data->cx++;
	if (window_copy_update_selection(w))
	window_copy_redraw_lines(w, data->cy, 1);
	else
	window_copy_update_cursor(w);
	}
	}

	void
	window_copy_cursor_up(struct window *w)
	{
	struct window_copy_mode_data *data = w->modedata;
	u_int ox, oy, px, py;

	oy = screen_y(&w->base, data->cy) - data->oy;
	ox = window_copy_find_length(w, oy);

	if (data->cy == 0)
	window_copy_scroll_down(w, 1);
	else {
	data->cy--;
	if (window_copy_update_selection(w))
	window_copy_redraw_lines(w, data->cy, 2);
	else
	window_copy_update_cursor(w);
	}

	py = screen_y(&w->base, data->cy) - data->oy;
	px = window_copy_find_length(w, py);

	if (data->cx + data->ox >= px \|\| data->cx + data->ox >= ox)
	window_copy_cursor_end_of_line(w);
	}

	void
	window_copy_cursor_down(struct window *w)
	{
	struct window_copy_mode_data *data = w->modedata;
	struct screen *s = &data->screen;
	u_int ox, oy, px, py;

	oy = screen_y(&w->base, data->cy) - data->oy;
	ox = window_copy_find_length(w, oy);

	if (data->cy == screen_last_y(s))
	window_copy_scroll_up(w, 1);
	else {
	data->cy++;
	if (window_copy_update_selection(w))
	window_copy_redraw_lines(w, data->cy - 1, 2);
	else
	window_copy_update_cursor(w);
	}

	py = screen_y(&w->base, data->cy) - data->oy;
	px = window_copy_find_length(w, py);

	if (data->cx + data->ox >= px \|\| data->cx + data->ox >= ox)
	window_copy_cursor_end_of_line(w);
	}

	void
	window_copy_cursor_next_word(struct window *w)
	{
	struct window_copy_mode_data *data = w->modedata;
	struct screen *s = &data->screen;
	u_int px, py, xx, skip;

	px = data->ox + data->cx;
	py = screen_y(&w->base, data->cy) - data->oy;
	xx = window_copy_find_length(w, py);

	skip = 1;
	if (px < xx) {
	/* If currently on a space, skip space. */
	if (window_copy_is_space(w, px, py))
	skip = 0;
	} else
	skip = 0;
	for (;;) {
	if (px >= xx) {
	if (skip) {
	px = xx;
	break;
	}

	while (px >= xx) {
	if (data->cy == screen_last_y(s)) {
	if (data->oy == 0)
	goto out;
	}

	px = 0;
	window_copy_cursor_down(w);

	py = screen_y(&w->base, data->cy) - data->oy;
	xx = window_copy_find_length(w, py);
	}
	}

	if (skip) {
	/* Currently skipping non-space (until space). */
	if (window_copy_is_space(w, px, py))
	break;
	} else {
	/* Currently skipping space (until non-space). */
	if (!window_copy_is_space(w, px, py))
	skip = 1;
	}

	px++;
	}
	out:

	/* On screen. */
	if (px > data->ox && px <= data->ox + screen_last_x(s))
	data->cx = px - data->ox;

	/* Off right of screen. */
	if (px > data->ox + screen_last_x(s)) {
	/* Move cursor to last and scroll screen. */
	window_copy_scroll_left(w,
	px - data->ox - screen_last_x(s));
	data->cx = screen_last_x(s);
	}

	/* Off left of screen. */
	if (px <= data->ox) {
	if (px < screen_last_x(s)) {
	/* Short enough to fit on screen. */
	window_copy_scroll_right(w, data->ox);
	data->cx = px;
	} else {
	/* Too long to fit on screen. */
	window_copy_scroll_right(
	w, data->ox - (px - screen_last_x(s)));
	data->cx = screen_last_x(s);
	}
	}

	if (window_copy_update_selection(w))
	window_copy_redraw_lines(w, data->cy, 1);
	else
	window_copy_update_cursor(w);
	}

	void
	window_copy_cursor_previous_word(struct window *w)
	{
	struct window_copy_mode_data *data = w->modedata;
	struct screen *s = &data->screen;
	u_int px, py, skip;

	px = data->ox + data->cx;
	py = screen_y(&w->base, data->cy) - data->oy;

	skip = 1;
	if (px != 0) {
	/* If currently on a space, skip space. */
	if (window_copy_is_space(w, px - 1, py))
	skip = 0;
	}
	for (;;) {
	while (px == 0) {
	if (data->cy == 0) {
	if (w->base.hsize == 0 \|\|
	data->oy >= w->base.hsize - 1)
	goto out;
	}

	window_copy_cursor_up(w);

	py = screen_y(&w->base, data->cy) - data->oy;
	px = window_copy_find_length(w, py);
	if (px != 0)
	goto out;
	}

	if (skip) {
	/* Currently skipping non-space (until space). */
	if (window_copy_is_space(w, px - 1, py))
	skip = 0;
	} else {
	/* Currently skipping space (until non-space). */
	if (!window_copy_is_space(w, px - 1, py))
	break;
	}

	px--;
	}
	out:

	/* On screen. */
	if (px > data->ox && px <= data->ox + screen_last_x(s))
	data->cx = px - data->ox;

	/* Off right of screen. */
	if (px > data->ox + screen_last_x(s)) {
	/* Move cursor to last and scroll screen. */
	window_copy_scroll_left(w,
	px - data->ox - screen_last_x(s));
	data->cx = screen_last_x(s);
	}

	/* Off left of screen. */
	if (px <= data->ox) {
	if (px < screen_last_x(s)) {
	/* Short enough to fit on screen. */
	window_copy_scroll_right(w, data->ox);
	data->cx = px;
	} else {
	/* Too long to fit on screen. */
	window_copy_scroll_right(
	w, data->ox - (px - screen_last_x(s)));
	data->cx = screen_last_x(s);
	}
	}

	if (window_copy_update_selection(w))
	window_copy_redraw_lines(w, data->cy, 1);
	else
	window_copy_update_cursor(w);
	}

	void
	window_copy_scroll_left(struct window *w, u_int nx)
	{
	struct window_copy_mode_data *data = w->modedata;
	struct screen *s = &data->screen;
	struct screen_write_ctx ctx;
	u_int i;

	if (data->ox > SHRT_MAX - nx)
	nx = SHRT_MAX - data->ox;
	if (nx == 0)
	return;
	data->ox += nx;
	window_copy_update_selection(w);

	screen_write_start_window(&ctx, w);
	for (i = 1; i < screen_size_y(s); i++) {
	screen_write_move_cursor(&ctx, 0, i);
	screen_write_delete_characters(&ctx, nx);
	}
	window_copy_write_columns(w, &ctx, screen_size_x(s) - nx, nx);
	window_copy_write_line(w, &ctx, 0);
	if (s->sel.flag) {
	window_copy_update_selection(w);
	window_copy_write_lines(w, &ctx, data->cy, 1);
	}
	screen_write_move_cursor(&ctx, data->cx, data->cy);
	screen_write_stop(&ctx);
	}

	void
	window_copy_scroll_right(struct window *w, u_int nx)
	{
	struct window_copy_mode_data *data = w->modedata;
	struct screen *s = &data->screen;
	struct screen_write_ctx ctx;
	u_int i;

	if (data->ox < nx)
	nx = data->ox;
	if (nx == 0)
	return;
	data->ox -= nx;
	window_copy_update_selection(w);

	screen_write_start_window(&ctx, w);
	for (i = 1; i < screen_size_y(s); i++) {
	screen_write_move_cursor(&ctx, 0, i);
	screen_write_insert_characters(&ctx, nx);
	}
	window_copy_write_columns(w, &ctx, 0, nx);
	window_copy_write_line(w, &ctx, 0);
	if (s->sel.flag)
	window_copy_write_lines(w, &ctx, data->cy, 1);
	screen_write_move_cursor(&ctx, data->cx, data->cy);
	screen_write_stop(&ctx);
	}

	void
	window_copy_scroll_up(struct window *w, u_int ny)
	{
	struct window_copy_mode_data *data = w->modedata;
	struct screen *s = &data->screen;
	struct screen_write_ctx ctx;

	if (data->oy < ny)
	ny = data->oy;
	if (ny == 0)
	return;
	data->oy -= ny;
	window_copy_update_selection(w);

	screen_write_start_window(&ctx, w);
	screen_write_move_cursor(&ctx, 0, 0);
	screen_write_delete_lines(&ctx, ny);
	window_copy_write_lines(w, &ctx, screen_size_y(s) - ny, ny);
	window_copy_write_line(w, &ctx, 0);
	if (s->sel.flag && screen_size_y(s) > ny)
	window_copy_write_lines(w, &ctx, screen_size_y(s) - ny - 1, 1);
	screen_write_move_cursor(&ctx, data->cx, data->cy);
	screen_write_stop(&ctx);
	}

	void
	window_copy_scroll_down(struct window *w, u_int ny)
	{
	struct window_copy_mode_data *data = w->modedata;
	struct screen *s = &data->screen;
	struct screen_write_ctx ctx;

	if (ny > w->base.hsize)
	return;

	if (data->oy > w->base.hsize - ny)
	ny = w->base.hsize - data->oy;
	if (ny == 0)
	return;
	data->oy += ny;
	window_copy_update_selection(w);

	screen_write_start_window(&ctx, w);
	screen_write_move_cursor(&ctx, 0, 0);
	screen_write_insert_lines(&ctx, ny);
	window_copy_write_lines(w, &ctx, 0, ny);
	if (s->sel.flag && screen_size_y(s) > ny)
	window_copy_write_lines(w, &ctx, ny, 1);
	else if (ny == 1) /* nuke position */
	window_copy_write_line(w, &ctx, 1);
	screen_write_move_cursor(&ctx, data->cx, data->cy);
	screen_write_stop(&ctx);
	}