langs a-z

Task/LZW-compression/Objective-C/lzw-compression-1.m

@@ -0,0 +1,97 @@
+#import <Foundation/Foundation.h>
+#import <stdio.h>
+
+@interface LZWCompressor : NSObject
+{
+  @private
+    NSMutableArray *iostream;
+    NSMutableDictionary *dict;
+    NSUInteger codemark;
+}
+
+-(LZWCompressor *) init;
+-(LZWCompressor *) initWithArray: (NSMutableArray *) stream;
+-(BOOL) compressData: (NSData *) string;
+-(void) setArray: (NSMutableArray *) stream;
+-(NSArray *) getArray;
+@end
+
+@implementation LZWCompressor : NSObject
+
+-(LZWCompressor *) init
+{
+   self = [super init];
+   if ( self )
+   {
+      iostream = nil;
+      codemark = 256;
+      dict = [[NSMutableDictionary alloc] initWithCapacity: 512];
+   }
+   return self;
+}
+
+-(LZWCompressor *) initWithArray: (NSMutableArray *) stream
+{
+   self = [self init];
+   if ( self )
+   {
+      [self setArray: stream];
+   }
+   return self;
+}
+
+-(void) dealloc
+{
+   [dict release];
+   [iostream release];
+   [super dealloc];
+}
+
+-(void) setArray: (NSMutableArray *) stream
+{
+   iostream = [stream retain];
+}
+
+-(BOOL) compressData: (NSData *) string;
+{
+    NSUInteger i;
+    unsigned char j;
+
+    // prepare dict
+    for(i=0; i < 256; i++)
+    {
+       j = i;
+       NSData *s = [NSData dataWithBytes: &j length: 1];
+       [dict setObject: [NSNumber numberWithUnsignedInt: i] forKey: s];
+    }
+
+    NSMutableData *w = [NSMutableData data];
+    NSMutableData *wc = [NSMutableData data];
+
+    for(i=0; i < [string length]; i++)
+    {
+       [wc setData: w];
+       [wc appendData: [string subdataWithRange: NSMakeRange(i, 1)]];
+       if ( [dict objectForKey: wc] != nil )
+       {
+          [w setData: wc];
+       } else {
+          [iostream addObject: [dict objectForKey: w]];
+          [dict setObject: [NSNumber numberWithUnsignedInt: codemark] forKey: wc];
+          codemark++;
+          [w setData: [string subdataWithRange: NSMakeRange(i, 1)]];
+       }
+    }
+    if ( [w length] != 0 )
+    {
+       [iostream addObject: [dict objectForKey: w]];
+    }
+    return YES;
+}
+
+-(NSArray *) getArray
+{
+  return iostream;
+}
+
+@end

Task/LZW-compression/Objective-C/lzw-compression-2.m

@@ -0,0 +1,26 @@
+const char *text = "TOBEORNOTTOBEORTOBEORNOT";
+
+int main()
+{
+  NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
+
+  NSMutableArray *array = [[NSMutableArray alloc] init];
+  LZWCompressor *lzw = [[LZWCompressor alloc]
+                        initWithArray: array ];
+  if ( lzw )
+  {
+     [lzw compressData: [NSData dataWithBytes: text
+                         length: strlen(text)]];
+     NSEnumerator *en = [array objectEnumerator];
+     id obj;
+     while( (obj = [en nextObject]) )
+     {
+        printf("%u\n", [obj unsignedIntValue]);
+     }
+     [lzw release];
+  }
+  [array release];
+
+  [pool release];
+  return EXIT_SUCCESS;
+}