Cut memory consumption by only allocating lines when there is actually data on them, and only as much as the right-most data. Everything else is filled in at runtime.

CHANGES

@@ -1,5 +1,7 @@
 21 November 2007
 
+* Create every line as zero length and only expand it as data is written,
+  rather than creating at full size immediately.
 * Make command output (eg list-keys) go to a scrollable window similar to
   scroll mode.
 * Redo screen redrawing so it is a) readable b) split into utility functions
@@ -247,4 +249,4 @@
   (including mutt, emacs). No status bar yet and no key remapping or other
   customisation.
 
-$Id: CHANGES,v 1.79 2007-11-21 19:44:04 nicm Exp $
+$Id: CHANGES,v 1.80 2007-11-21 22:20:44 nicm Exp $

cmd-list-windows.c

@@ -1,4 +1,4 @@
-/* $Id: cmd-list-windows.c,v 1.10 2007-11-21 13:11:41 nicm Exp $ */
+/* $Id: cmd-list-windows.c,v 1.11 2007-11-21 22:20:44 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
@@ -42,15 +42,28 @@ const struct cmd_entry cmd_list_windows_entry = {
 void
 cmd_list_windows_exec(unused void *ptr, struct cmd_ctx *ctx)
 {
-	struct winlink	*wl;
+	struct winlink		*wl;
-	struct window	*w;
+	struct window		*w;
+	u_int			 i, sy;
+	unsigned long long	 size;
 
 	RB_FOREACH(wl, winlinks, &ctx->session->windows) {
 		w = wl->window;
-		ctx->print(ctx, "%d: %s \"%s\" (%s) [%ux%u] [history %u]",
+
+		sy = w->screen.hsize + w->screen.dy;
+		size = sizeof *w;
+		for (i = 0; i < sy; i++)
+			size += 4 + w->screen.grid_size[i] * 3;
+		size += sy * (sizeof *w->screen.grid_data);
+		size += sy * (sizeof *w->screen.grid_attr);
+		size += sy * (sizeof *w->screen.grid_colr);
+		size += sy * (sizeof *w->screen.grid_size);
+
+		ctx->print(ctx,
+		    "%d: %s \"%s\" (%s) [%ux%u] [history %u] [%llu bytes]",
 		    wl->idx, w->name, w->screen.title, ttyname(w->fd),
 		    screen_size_x(&w->screen), screen_size_y(&w->screen),
-		    w->screen.hsize);
+		    w->screen.hsize, size);
 	}
 
 	if (ctx->cmdclient != NULL)

screen-display.c

@@ -1,4 +1,4 @@
-/* $Id: screen-display.c,v 1.4 2007-11-21 21:28:58 nicm Exp $ */
+/* $Id: screen-display.c,v 1.5 2007-11-21 22:20:44 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
@@ -139,9 +139,7 @@ screen_display_cursor_set(struct screen *s, u_char ch)
 	px = screen_x(s, s->cx);
 	py = screen_y(s, s->cy);
 
-	s->grid_data[py][px] = ch;
+	screen_set_cell(s, px, py, ch, s->attr, s->colr);
-	s->grid_attr[py][px] = s->attr;
-	s->grid_colr[py][px] = s->colr;
 }
 
 /* Move cursor up and scroll if necessary. */
@@ -405,11 +403,15 @@ screen_display_insert_characters(struct screen *s, u_int px, u_int py, u_int nx)
 
 	py = screen_y(s, py);
 
+	/* XXX Cheat and make the line a full line. */
+	if (s->grid_size[py] < screen_size_x(s))
+		screen_expand_line(s, py, screen_size_x(s));
+
 	/*
 	 * Inserting a range of nx at px.
 	 *
 	 * - Move sx - (px + nx) from px to px + nx.
-	 * - Clear the range at px.
+	 * - Clear the range at px to px + nx.
 	 */
 
 	if (px + nx != screen_last_x(s)) {
@@ -418,6 +420,7 @@ screen_display_insert_characters(struct screen *s, u_int px, u_int py, u_int nx)
 		memmove(&s->grid_attr[py][px + nx], &s->grid_attr[py][px], mx);
 		memmove(&s->grid_colr[py][px + nx], &s->grid_colr[py][px], mx);
 	}
+
 	memset(&s->grid_data[py][px], SCREEN_DEFDATA, nx);
 	memset(&s->grid_attr[py][px], SCREEN_DEFATTR, nx);
 	memset(&s->grid_colr[py][px], SCREEN_DEFCOLR, nx);
@@ -437,11 +440,15 @@ screen_display_delete_characters(struct screen *s, u_int px, u_int py, u_int nx)
 
 	py = screen_y(s, py);
 
+	/* XXX Cheat and make the line a full line. */
+	if (s->grid_size[py] < screen_size_x(s))
+		screen_expand_line(s, py, screen_size_x(s));
+
 	/*
 	 * Deleting the range from px to px + nx.
 	 *
 	 * - Move sx - (px + nx) from px + nx to px.
-	 * - Clear the range from the last x - (rx - lx)  to the last x.
+	 * - Clear the range from sx - nx to sx.
 	 */
 
 	if (px + nx != screen_last_x(s)) {

screen.c

@@ -1,4 +1,4 @@
-/* $Id: screen.c,v 1.34 2007-11-21 21:28:58 nicm Exp $ */
+/* $Id: screen.c,v 1.35 2007-11-21 22:20:44 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
@@ -110,7 +110,7 @@ screen_create(struct screen *s, u_int dx, u_int dy)
 void
 screen_resize(struct screen *s, u_int sx, u_int sy)
 {
-	u_int	i, ox, oy, ny, my;
+	u_int	ox, oy, ny, my;
 
 	if (sx < 1)
 		sx = 1;
@@ -126,23 +126,6 @@ screen_resize(struct screen *s, u_int sx, u_int sy)
 	 * X dimension.
 	 */
 	if (sx != ox) {
-		/* Resize on-screen lines. */
-		for (i = s->hsize; i < s->hsize + oy; i++) {
-			if (sx > s->grid_size[i]) {
-				s->grid_data[i] = 
-				    xrealloc(s->grid_data[i], sx, 1);
-				s->grid_attr[i] =
-				    xrealloc(s->grid_attr[i], sx, 1);
-				s->grid_colr[i] =
-				    xrealloc(s->grid_colr[i], sx, 1);
-				s->grid_size[i] = sx;
-			}
-			if (sx > ox) {
-				screen_fill_cells(s, ox, i, sx - ox,
-				    SCREEN_DEFDATA, SCREEN_DEFATTR,
-				    SCREEN_DEFCOLR);
-			}
-		}
 		if (s->cx >= sx)
 			s->cx = sx - 1;
 		s->dx = sx;
@@ -201,6 +184,56 @@ screen_resize(struct screen *s, u_int sx, u_int sy)
 	s->rlower = s->dy - 1;
 }
 
+/* Expand line. */
+void
+screen_expand_line(struct screen *s, u_int py, u_int nx)
+{
+	u_int	ox;
+
+	ox = s->grid_size[py];
+	s->grid_size[py] = nx;
+
+	s->grid_data[py] = xrealloc(s->grid_data[py], 1, nx);
+	memset(&s->grid_data[py][ox], SCREEN_DEFDATA, nx - ox);
+	s->grid_attr[py] = xrealloc(s->grid_attr[py], 1, nx);
+	memset(&s->grid_attr[py][ox], SCREEN_DEFATTR, nx - ox);
+	s->grid_colr[py] = xrealloc(s->grid_colr[py], 1, nx);
+	memset(&s->grid_colr[py][ox], SCREEN_DEFCOLR, nx - ox);
+}
+
+/* Get cell. */
+void
+screen_get_cell(struct screen *s,
+    u_int cx, u_int cy, u_char *data, u_char *attr, u_char *colr)
+{
+	if (cx >= s->grid_size[cy]) {
+		*data = SCREEN_DEFDATA;
+		*attr = SCREEN_DEFATTR;
+		*colr = SCREEN_DEFCOLR;
+	} else {
+		*data = s->grid_data[cy][cx];
+		*attr = s->grid_attr[cy][cx];
+		*colr = s->grid_colr[cy][cx];
+	}
+}
+
+/* Set a cell. */
+void
+screen_set_cell(struct screen *s,
+    u_int cx, u_int cy, u_char data, u_char attr, u_char colr)
+{
+	if (cx >= s->grid_size[cy]) {
+		if (data == SCREEN_DEFDATA &&
+		    attr == SCREEN_DEFATTR && colr == SCREEN_DEFCOLR)
+			return;
+		screen_expand_line(s, cy, cx + 1);
+	}
+
+	s->grid_data[cy][cx] = data;
+	s->grid_attr[cy][cx] = attr;
+	s->grid_colr[cy][cx] = colr;
+}
+
 /* Destroy a screen. */
 void
 screen_destroy(struct screen *s)
@@ -235,6 +268,20 @@ screen_draw_start(struct screen_draw_ctx *ctx,
 		input_store_zero(b, CODE_CURSOROFF);
 }
 
+/* Get cell data during drawing. */
+void
+screen_draw_get_cell(struct screen_draw_ctx *ctx,
+    u_int px, u_int py, u_char *data, u_char *attr, u_char *colr)
+{
+	struct screen	*s = ctx->s;
+	u_int		 cx, cy;
+	
+	cx = ctx->ox + px;
+	cy = screen_y(s, py) - ctx->oy;
+
+	screen_get_cell(s, cx, cy, data, attr, colr);
+}
+
 /* Finalise drawing. */
 void
 screen_draw_stop(struct screen_draw_ctx *ctx)
@@ -254,28 +301,6 @@ screen_draw_stop(struct screen_draw_ctx *ctx)
 		input_store_zero(b, CODE_CURSORON);
 }
 
-/* Get cell data. */
-void
-screen_draw_get_cell(struct screen_draw_ctx *ctx,
-    u_int px, u_int py, u_char *data, u_char *attr, u_char *colr)
-{
-	struct screen	*s = ctx->s;
-	u_int		 cx, cy;
-	
-	cx = ctx->ox + px;
-	cy = screen_y(s, py) - ctx->oy;
-
-	if (cx >= s->grid_size[cy]) {
-		*data = SCREEN_DEFDATA;
-		*attr = SCREEN_DEFATTR;
-		*colr = SCREEN_DEFCOLR;
-	} else {
-		*data = s->grid_data[cy][cx];
-		*attr = s->grid_attr[cy][cx];
-		*colr = s->grid_colr[cy][cx];
-	}
-}
-
 /* Move cursor. */
 void
 screen_draw_move(struct screen_draw_ctx *ctx, u_int px, u_int py)
@@ -372,16 +397,13 @@ screen_make_lines(struct screen *s, u_int py, u_int ny)
 	u_int	i;
 
 	for (i = py; i < py + ny; i++) {
-		s->grid_data[i] = xmalloc(s->dx);
+		s->grid_data[i] = NULL;
-		s->grid_attr[i] = xmalloc(s->dx);
+		s->grid_attr[i] = NULL;
-		s->grid_colr[i] = xmalloc(s->dx);
+		s->grid_colr[i] = NULL;
-		s->grid_size[i] = s->dx;
+		s->grid_size[i] = 0;
 	}
-	screen_fill_lines(
-	    s, py, ny, SCREEN_DEFDATA, SCREEN_DEFATTR, SCREEN_DEFCOLR);
 }
 
-
 /* Free a range of ny lines at py. */
 void
 screen_free_lines(struct screen *s, u_int py, u_int ny)
@@ -389,9 +411,15 @@ screen_free_lines(struct screen *s, u_int py, u_int ny)
 	u_int	i;
 
 	for (i = py; i < py + ny; i++) {
-		xfree(s->grid_data[i]);
+		if (s->grid_data[i] != NULL)
-		xfree(s->grid_attr[i]);
+			xfree(s->grid_data[i]);
-		xfree(s->grid_colr[i]);
+		s->grid_data[i] = NULL;
+		if (s->grid_attr[i] != NULL)
+			xfree(s->grid_attr[i]);
+		s->grid_attr[i] = NULL;
+		if (s->grid_colr[i] != NULL)
+			xfree(s->grid_colr[i]);
+		s->grid_colr[i] = NULL;
 		s->grid_size[i] = 0;
 	}
 }
@@ -426,7 +454,8 @@ void
 screen_fill_cells(struct screen *s,
     u_int px, u_int py, u_int nx, u_char data, u_char attr, u_char colr)
 {
-	memset(&s->grid_data[py][px], data, nx);
+	u_int	i;
-	memset(&s->grid_attr[py][px], attr, nx);
+
-	memset(&s->grid_colr[py][px], colr, nx);
+	for (i = px; i < px + nx; i++)
+		screen_set_cell(s, i, py, data, attr, colr);
 }

tmux.h

@@ -1,4 +1,4 @@
-/* $Id: tmux.h,v 1.91 2007-11-21 20:04:37 nicm Exp $ */
+/* $Id: tmux.h,v 1.92 2007-11-21 22:20:44 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
@@ -61,7 +61,7 @@ extern char    *__progname;
 #define TTY_NAME_MAX 32
 #endif
 
-#define MAXTITLELEN	192
+#define MAXTITLELEN	128
 
 /* Fatal errors. */
 #define fatal(msg) log_fatal("%s: %s", __func__, msg);
@@ -764,6 +764,10 @@ u_char	 screen_stringcolour(const char *);
 void	 screen_create(struct screen *, u_int, u_int);
 void	 screen_destroy(struct screen *);
 void	 screen_resize(struct screen *, u_int, u_int);
+void	 screen_expand_line(struct screen *, u_int, u_int);
+void	 screen_get_cell(
+    	     struct screen *, u_int, u_int, u_char *, u_char *, u_char *);
+void	 screen_set_cell(struct screen *, u_int, u_int, u_char, u_char, u_char);
 void	 screen_draw_start(struct screen_draw_ctx *,
     	     struct screen *, struct buffer *, u_int, u_int);
 void	 screen_draw_stop(struct screen_draw_ctx *);