Just another update

Task/SHA-256/Objective-C/sha-256.m

@@ -1,21 +1,19 @@
-#import <CommonCrypto/CommonHMAC.h>
+#import <Cocoa/Cocoa.h>
+#import <CommonCrypto/CommonDigest.h>
 
-@implementation AppDelegate
-
-- (void)applicationDidFinishLaunching:(NSNotification *)aNotification {
- NSString* key = @"secret";
- NSString* data = @"Message";
-
- const char *cKey = [key cStringUsingEncoding:NSASCIIStringEncoding];
- const char *cData = [data cStringUsingEncoding:NSASCIIStringEncoding];
- unsigned char cHMAC[CC_SHA256_DIGEST_LENGTH];
- CCHmac(kCCHmacAlgSHA256, cKey, strlen(cKey), cData, strlen(cData), cHMAC);
-
- NSMutableString* result = [NSMutableString stringWithCapacity:(CC_SHA256_DIGEST_LENGTH * 2)];
-	
-  for(CC_LONG i = 0; i < CC_SHA256_DIGEST_LENGTH; i++)
-   [result appendFormat:@"%02x", cHMAC[i]];
-
-  NSLog(@"Sha-256: %@", result);
 
+int main(int argc, char ** argv) {
+    NSString * msg = @"Rosetta code";
+    unsigned char buf[CC_SHA256_DIGEST_LENGTH];
+    const char * rc = [msg cStringUsingEncoding:NSASCIIStringEncoding];
+    if (! CC_SHA256(rc, strlen(rc), buf)) {
+        NSLog(@"Failure...");
+        return -1;
+    }
+    NSMutableString * res = [NSMutableString stringWithCapacity:(CC_SHA256_DIGEST_LENGTH * 2)];
+    for (int i = 0; i < CC_SHA256_DIGEST_LENGTH; ++i) {
+        [res appendFormat:@"%02x", buf[i]];
+    }
+    NSLog(@"Output: %@", res);
+    return 0;
 }