Data commit

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

@@ -0,0 +1,86 @@
+#import <Foundation/Foundation.h>
+#import <stdio.h>
+
+@interface LZWCompressor : NSObject
+{
+  @private
+    NSMutableArray *iostream;
+    NSMutableDictionary *dict;
+    NSUInteger codemark;
+}
+
+-(instancetype) init;
+-(instancetype) initWithArray: (NSMutableArray *) stream;
+-(BOOL) compressData: (NSData *) string;
+-(void) setArray: (NSMutableArray *) stream;
+-(NSArray *) getArray;
+@end
+
+@implementation LZWCompressor : NSObject
+
+-(instancetype) init
+{
+   self = [super init];
+   if ( self )
+   {
+      iostream = nil;
+      codemark = 256;
+      dict = [[NSMutableDictionary alloc] initWithCapacity: 512];
+   }
+   return self;
+}
+
+-(instancetype) initWithArray: (NSMutableArray *) stream
+{
+   self = [self init];
+   if ( self )
+   {
+      [self setArray: stream];
+   }
+   return self;
+}
+
+-(void) setArray: (NSMutableArray *) stream
+{
+   iostream = stream;
+}
+
+-(BOOL) compressData: (NSData *) string;
+{
+    // prepare dict
+    for(NSUInteger i=0; i < 256; i++)
+    {
+       unsigned char j = i;
+       NSData *s = [NSData dataWithBytes: &j length: 1];
+       dict[s] = @(i);
+    }
+
+    NSData *w = [NSData data];
+
+    for(NSUInteger i=0; i < [string length]; i++)
+    {
+       NSMutableData *wc = [NSMutableData dataWithData: w];
+       [wc appendData: [string subdataWithRange: NSMakeRange(i, 1)]];
+       if ( dict[wc] != nil )
+       {
+          w = wc;
+       } else {
+          [iostream addObject: dict[w]];
+          dict[wc] = @(codemark);
+          codemark++;
+          w = [string subdataWithRange: NSMakeRange(i, 1)];
+       }
+    }
+    if ( [w length] != 0 )
+    {
+       [iostream addObject: dict[w]];
+    }
+    return YES;
+}
+
+-(NSArray *) getArray
+{
+  return iostream;
+}
+
+@end

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

@@ -0,0 +1,21 @@
+NSString *text = @"TOBEORNOTTOBEORTOBEORNOT";
+
+int main()
+{
+  @autoreleasepool {
+
+    NSMutableArray *array = [[NSMutableArray alloc] init];
+    LZWCompressor *lzw = [[LZWCompressor alloc]
+                          initWithArray: array ];
+    if ( lzw )
+    {
+       [lzw compressData: [text dataUsingEncoding: NSUTF8StringEncoding]];
+       for ( id obj in array )
+       {
+          printf("%u\n", [obj unsignedIntValue]);
+       }
+    }
+
+  }
+  return EXIT_SUCCESS;
+}