1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
|
/*
Copyright (C) 2000 Paul Wilkins
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
/* undo.c by Paul Wilkins */
#include <stdio.h>
#include "undo.h"
#include "error.h"
#include "stack.h"
#include "number.h"
/* must be at least 2 */
#define MAX_UNDO_LEVELS 10
int nSavedItems[MAX_UNDO_LEVELS];
int nUndoItems[MAX_UNDO_LEVELS];
struct Stack undoStacks[MAX_UNDO_LEVELS];
int ringIndx;
int undoLevel;
void initUndoSystem(){
int i;
static int initialized = 0;
if(initialized != 0){
for(i=0; i<MAX_UNDO_LEVELS; i++){
clearNamedStack(&(undoStacks[i]));
}
}
initialized = 1;
for(i=0; i<MAX_UNDO_LEVELS; i++){
nSavedItems[i] = 0;
nUndoItems[i] = 0;
undoStacks[i].head = NULL;
undoStacks[i].length = 0;
}
ringIndx = 0;
undoLevel = 0;
}
void UndoStack(){
int i;
if(undoLevel == 0){
setStringError("Undo Error: Nothing to Undo.");
return;
}
ringIndx--;
if(ringIndx < 0) ringIndx = MAX_UNDO_LEVELS - 1;
undoLevel--;
if(undoLevel <= 0) undoLevel = 0;
/* throw away the stuff we are undoing */
for(i=0; i<nUndoItems[ringIndx]; i++){
freeNumber(Pop());
}
/* restore the origional numbers */
copyStack(&(undoStacks[ringIndx]), getStack(), nSavedItems[ringIndx]);
/* clear this stack */
clearNamedStack(&(undoStacks[ringIndx]));
nSavedItems[ringIndx] = 0;
}
/* Whoops, we called SaveStackState but didn't mean to */
void CancelStackState(){
nSavedItems[ringIndx] = 0;
/* clear this stack */
clearNamedStack(&(undoStacks[ringIndx]));
}
/* Called before anything that modifies the stack.
* Stores args worth of numbers from the stack which will be
* used to restore tohe stack if UndoStack is called.
*/
void SaveStackState(int args){
/* make space for the new saved stack */
if(undoLevel >= MAX_UNDO_LEVELS){
clearNamedStack(&(undoStacks[ringIndx]));
}
/* save the new info */
nSavedItems[ringIndx] = args;
copyStack(getStack(), &(undoStacks[ringIndx]), args);
}
void AddStackState(int args){
/* save the new info */
nSavedItems[ringIndx] += args;
copyStack(getStack(), &(undoStacks[ringIndx]), args);
}
/* Called after anything that modifies the stack.
* Records the number of stack elements that must be poped
* from the stack to undo the last operation if UndoStack
* is called.
*/
void UndoStackState(int args){
nUndoItems[ringIndx] = args;
undoLevel++;
if(undoLevel >= MAX_UNDO_LEVELS) undoLevel = MAX_UNDO_LEVELS;
ringIndx++;
if(ringIndx >= MAX_UNDO_LEVELS) ringIndx = 0;
}
|
