Add method to make Base64 SHA1 digest from string. Tests.

Source/Categories/NSString+PKAdditions.h

@@ -6,10 +6,12 @@
 //  Copyright (c) 2013 Pavel Kunc. All rights reserved.
 //
 
-#import <Foundation/Foundation.h>
+@import Foundation;
+#import <CommonCrypto/CommonDigest.h>
 
 @interface NSString (PKAdditions)
 
-- (id)pk_stringByReplacingNumericHTMLEntities;
+- (instancetype)pk_stringByReplacingNumericHTMLEntities;
+- (instancetype)pk_SHA1_Base64;
 
 @end

Source/Categories/NSString+PKAdditions.m

@@ -14,7 +14,9 @@
 
 @implementation NSString (PKAdditions)
 
-- (id)pk_stringByReplacingNumericHTMLEntities {
+//TODO: This only handles decimal HTML entity codes but not hexa �
+//      (pavel, Mon  4 Nov 20:39:27 2013)
+- (instancetype)pk_stringByReplacingNumericHTMLEntities {
     NSString *string = [self copy];
 
     NSRange entityEnd;
@@ -36,4 +38,14 @@ - (id)pk_stringByReplacingNumericHTMLEntities {
     return string;
 }
 
+- (instancetype)pk_SHA1_Base64 {
+    unsigned char digest[CC_SHA1_DIGEST_LENGTH];
+    NSData *stringBytes = [self dataUsingEncoding:NSUTF8StringEncoding];
+    if (CC_SHA1([stringBytes bytes], [stringBytes length], digest) != digest) return nil;
+
+    NSData *sha = [NSData dataWithBytes:digest length:CC_SHA1_DIGEST_LENGTH];
+    return [sha base64EncodedStringWithOptions:NSDataBase64Encoding64CharacterLineLength];
+}
+
 @end
+

Specs/Categories/NSString+PKAdditionsSpec.m

@@ -0,0 +1,62 @@
+//
+//  NSString+PKAdditionsSpec.m
+//  NSString+PKAdditions Spec
+//
+//  Created by Pavel Kunc on 04/11/2013.
+//
+
+#import "Kiwi.h"
+#import "NSString+PKAdditions.h"
+
+SPEC_BEGIN(NSString_PKAdditionsSpec)
+
+describe(@"pk_stringByReplacingNumericHTMLEntities", ^{
+
+    context(@"when given string without any HTML entities", ^{
+        it(@"should return the unchanged string", ^{
+            NSString *original = @"Lorem ipsum...";
+            [[[original pk_stringByReplacingNumericHTMLEntities] should] equal:original];
+        });
+    });
+
+    context(@"when given empty string", ^{
+        it(@"should return empty string", ^{
+            [[[@"" pk_stringByReplacingNumericHTMLEntities] should] equal:@""];
+        });
+    });
+
+
+    // http://www.fileformat.info/info/unicode/char/2018/index.htm
+    // http://www.fileformat.info/info/unicode/char/2019/index.htm
+    context(@"when given string with HTML entities", ^{
+        it(@"should return the string with all entities converted to characters", ^{
+            NSString *original = @"Lorem ‘ipsum’...";
+            NSString *result = @"Lorem ‘ipsum’...";
+            [[[original pk_stringByReplacingNumericHTMLEntities] should] equal:result];
+        });
+    });
+
+});
+
+describe(@"pk_SHA1_Base64", ^{
+
+    context(@"when string is empty", ^{
+        it(@"should return SHA1 special value for empty string", ^{
+            // Digest::SHA1.hexdigest('') => "da39a3ee5e6b4b0d3255bfef95601890afd80709"
+            // Digest::SHA1.base64digest('') => "2jmj7l5rSw0yVb/vlWAYkK/YBwk="
+            [[[@"" pk_SHA1_Base64] should] equal:@"2jmj7l5rSw0yVb/vlWAYkK/YBwk="];
+        });
+    });
+
+    context(@"when string is not empty", ^{
+        it(@"should return Base64 representation of the SHA1 of the string", ^{
+            NSString *string = @"abcdefghijklmnopqrstuvwxyz";
+            NSString *hash = @"MtEMe4z5ZXDKBM438qGdhCQNOok=";
+            [[[string pk_SHA1_Base64] should] equal:hash];
+        });
+    });
+
+});
+
+SPEC_END
+