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#import "list.h"
@implementation List
// Create a new list
+new {
self = [super alloc];
return [self init];
}
// Initialize the list to a new state
-init {
int i;
nitems = 0;
maxitems = 10;
items = (id *) malloc(maxitems*sizeof(id));
for (i = 0; i < maxitems; i++)
items[i] = 0;
return self;
}
// Destroy the list. Does not destroy the objects in the list!
- free {
free(items);
[super free];
}
// Expand the list
-(void) expand {
int i;
maxitems = 2*maxitems;
items = (id *) realloc(items,maxitems*sizeof(id));
};
// Append a new item to the list
-(void) append: (id) item {
if (nitems == maxitems) [self expand];
items[nitems] = item;
nitems++;
}
// Insert a new item to the list
-(void) insert: (id) item : (int) pos {
int i;
if (pos < 0) pos = 0;
if (pos > nitems) pos = nitems;
if (nitems == maxitems) [self expand];
for (i = nitems; i > pos; i++)
items[i] = items[i-1];
items[pos] = item;
nitems++;
}
// Delete an item from the list
-remove: (int) pos {
int i;
id it;
if (pos < 0) return nil;
if (pos >= nitems) return nil;
it = items[pos];
for (i = pos; i < nitems-1; i++)
items[i] = items[i+1];
nitems--;
return it;
}
// Replace an item in the list. Returns the old item
-replace: (id) item : (int) pos {
id i;
i = items[pos];
items[pos] = item;
return i;
}
// Get an item from the list
-get: (int) i {
if (i < 0) return nil;
if (i >= nitems) return nil;
return items[i];
}
// Find an item in the list.
-(int) index: obj {
int i;
for (i = 0; i < nitems; i++)
if (items[i] == obj) return i;
return -1;
}
// Return the length of the list
-(int) len {
return nitems;
}
@end
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