preliminary support for undo

6 files changed, 117 insertions, 6 deletions

diff --git a/TODO b/TODO
index 71689fc..4b893ea 100644
--- a/TODO
+++ b/TODO
@@ -1,4 +1,5 @@
 + optimize redraws (redraw only the modified rectangle)
++ undo (by storing lines changed across insert/remove operations)
 - fix bug with 'g' commands in arrow mode
 - add screen geometry option (-g 25x80?)
 - read file at point
@@ -18,7 +19,6 @@
   * yank
   * fill
   * cut 
-- undo (by storing lines changed across insert/remove operations)
 - manage special chars (DEL/CANC) during text insert
   (also do not print unmanaged chars!)
 - allow scrolling (both vertical and horizontal)
diff --git a/draw.c b/draw.c
index 3c98534..e3bdbce 100644
--- a/draw.c
+++ b/draw.c
@@ -1,4 +1,5 @@
 #include <stdlib.h>
+#include <string.h>
 
 #include "gramscii.h"
 #include "config.h"
@@ -103,16 +104,19 @@ void draw_box(int x1, int y1, int fix){
 	int i;
 	void (*f)(int, int, char);
 
-	if (fix == FIX)
-		f = set_xy;
-	else
-		f = draw_xy;
 
 	xmin = MIN(x, x1);
 	xmax = MAX(x, x1);
 	ymin = MIN(y, y1);
 	ymax = MAX(y, y1);
 
+	if (fix == FIX){
+		f = set_xy;
+		copy_lines_to_ring(ymin, ymax, CUR);
+	}
+	else
+		f = draw_xy;
+
 	for(i=xmin+1; i<=xmax; i++){
 		f(i, ymin, line_h);
 		f(i, ymax, line_h);
@@ -125,6 +129,8 @@ void draw_box(int x1, int y1, int fix){
 	f(xmin, ymax, corner);
 	f(xmax, ymin, corner);
 	f(xmax, ymax, corner);
+	if (fix == FIX)
+		copy_lines_to_ring(ymin, ymax, LST);
 	show_cursor();
 }
 
@@ -157,6 +163,7 @@ update_box:
 
 void draw_arrow(int x, int y, char *a, int a_len, int fix){
 
+	/* FIXME: copy affected lines to undo */
 	int i, j, cur_dir;
 	char line;
 	void (*f)(int, int, char);
@@ -266,6 +273,7 @@ void do_erase(int x1, int y1){
 
 
 void erase(FILE *fc){
+	/*FIXME: add affected lines to undo */
 	char c;
 	int orig_x = x, orig_y = y;
 	status_bar();
@@ -308,8 +316,11 @@ void visual_box(FILE *fc){
 			case 'x':/* erase */
 				if (c == 'x')
 					yank_region(MIN(orig_x,x), MIN(orig_y,y), MAX(orig_x, x), MAX(orig_y, y));
+				copy_lines_to_ring(MIN(orig_y, y), MAX(orig_y, y), CUR);
 				erase_box(orig_x, orig_y, f);
 				erase_blank_lines(MIN(y,orig_y), MAX(y, orig_y));
+				copy_lines_to_ring(MIN(orig_y, y), MAX(orig_y, y), LST);
+		
 				modified = 1;
 				goto vis_exit;
 				break;
@@ -331,6 +342,42 @@ vis_exit:
 }
 
 void paste(){
+	int y2;
+
+	y2 = y + cutbuf.num - 1;
+	copy_lines_to_ring(y, y2, CUR);
 	paste_region(x, y);
+	copy_lines_to_ring(y, y2, LST);
+	redraw();
+}
+
+void put_lines(lineset_t *u){
+	int i, n;
+	
+	for (i=0; i< u->num; i++){
+		n = u->l[i].n;
+		ensure_line_length(&(screen.l[i]), u->l[i].lst);
+		strcpy(screen.l[n].s, u->l[i].s);
+		screen.l[n].lst = u->l[i].lst;
+	}
+}
+
+
+void undo_change(){
+	if (undo_cur >= 0){
+		put_lines(& (undo[undo_cur]));
+		undo_cur --;
+	}
+	redraw();
+	modified = 1;
+}
+
+void redo_change(){
+	if (undo_cur < undo_lst){
+		undo_cur ++;
+		put_lines(& (undo[undo_cur]));
+	}
 	redraw();
+	modified = 1;
 }
+
diff --git a/gramscii.h b/gramscii.h
index a08d211..73b9db7 100644
--- a/gramscii.h
+++ b/gramscii.h
@@ -44,6 +44,9 @@
 #define VIDEO_NRM 0
 #define VIDEO_REV 7 
 
+#define CUR 0x01
+#define LST 0x02
+
 /** types **/
 
 typedef struct{
@@ -59,6 +62,7 @@ typedef struct{
 	line_t *l;
 } lineset_t;
 
+
 /** MACROS **/
 
 #define MIN(x,y)  (x) < (y) ? (x) : (y)
@@ -73,6 +77,11 @@ typedef struct{
 
 lineset_t screen;
 lineset_t cutbuf;
+lineset_t *undo;
+
+int undo_sz;
+int undo_cur;
+int undo_lst;
 
 int WIDTH, HEIGHT;
 
@@ -155,6 +164,8 @@ void ensure_line_length(line_t *l, int len);
 void ensure_num_lines(lineset_t *ls, int n);
 void yank_region(int x1, int y1, int x2, int y2);
 void paste_region(int x1, int y1);
-
+void copy_lines_to_ring(int y1, int y2, int which);
+void undo_change();
+void redo_change();
 
 #endif
diff --git a/lineset.c b/lineset.c
index f672798..40fe3f0 100644
--- a/lineset.c
+++ b/lineset.c
@@ -58,6 +58,7 @@ void ensure_num_lines(lineset_t *ls, int n){
 	}
 }
 
+
 void dump_lines(lineset_t ls, FILE *f){
 	int i;
 	for (i=0; i<ls.num ;i++){
@@ -124,3 +125,45 @@ void paste_region(int x1, int y1){
 	}
 	redraw();
 }
+
+void copy_lines_to_ring(int y1, int y2, int which){
+	lineset_t *tmp;
+	int i, len, *idx;
+
+	if (y1 > y2){
+		y1 ^= y2;
+		y2 ^= y1;
+		y1 ^= y2;
+	}
+	if (which == CUR)
+		idx = &undo_cur;
+	else
+		idx = &undo_lst;
+	if (*idx == undo_sz - 1){
+		undo_sz += 10;
+		tmp = realloc(undo, undo_sz * sizeof(lineset_t));
+		if (tmp == NULL){
+			fprintf(stderr, "Error allocating undo buffer");
+			exit(1);
+		}
+		undo = tmp;
+	}
+	(*idx) ++;
+	ensure_num_lines(&(undo[*idx]), y2 - y1 + 1);
+	for(i=y1; i<=y2; i++){
+		len = strlen(screen.l[i].s);
+		ensure_line_length(&(undo[*idx].l[i-y1]), len);
+		strcpy(undo[*idx].l[i-y1].s, screen.l[i].s);
+		undo[*idx].l[i-y1].n = i;
+		undo[*idx].l[i-y1].lst = screen.l[i].lst;
+	}
+	undo[*idx].num = y2 - y1 + 1;
+	if (which == CUR)
+		undo_lst = undo_cur;
+#ifdef DEBUG
+	fprintf(stderr, "undo_ring: y1: %d y2: %d idx: %d\n", y1, y2, *idx);
+	for(i=0; i<undo[undo_cur].num; i++){
+		fprintf(stderr, "UU: %d| %s\n", undo[*idx].l[i].n, undo[*idx].l[i].s);
+	}
+#endif	
+}
diff --git a/main.c b/main.c
index d2d5a55..4118ecc 100644
--- a/main.c
+++ b/main.c
@@ -122,6 +122,12 @@ void commands(FILE *fc){
 				case 'p':
 					paste();
 					break;
+				case 'u':
+					undo_change();
+					break;
+				case 'U':
+					redo_change();
+					break;
 				case 'q':
 					check_modified(fc);/** FALLTHROUGH **/
 				case 'Q':
diff --git a/screen.c b/screen.c
index 3cbfe12..93dd459 100644
--- a/screen.c
+++ b/screen.c
@@ -408,6 +408,10 @@ void init_screen(){
 	cutbuf.sz = 0;
 	cutbuf.l = NULL;
 	cutbuf.num = 0;
+	
+	undo_sz = 0;
+	undo_cur = -1;
+	undo_lst = -1;
 }
 
 void find_nonblank_rect(int *x1, int *y1, int *x2, int *y2){