0xced · April 1, 2012 12:24 · Apr 1, 2012 · Apr 1, 2012
diff --git a/NSString.m b/NSString.m
@@ -1,3 +1,9 @@
+/*
+ * Most NSString instances will actually be __NSCFString instances, so here are both NSString and __NSCFString implementations.
+ * If you know how to create an NSString instance whose class is actually NSString please let me know.
+ * Other possible concrete subclasses of NSString are: NSConstantString, __NSCFConstantString, NSPathStore2, NSSimpleCString and __NSLocalizedString.
+ */
+
 // CoreFoundation.framework 635.19.0 (Mac OS X 10.7.3)
 @implementation NSObject
 
@@ -10,11 +16,106 @@ - (BOOL) isNSString__
 
 @implementation __NSCFString
 
+static CFStringEncoding enc = 0;
+
 - (BOOL) isNSString__
 {
 	return YES;
 }
 
+- (BOOL) isEqual:(id)string
+{
+	if (self == string)
+	{
+		return YES;
+	}
+	else if (string == nil)
+	{
+		return NO
+	}
+	else
+	{
+		Class stringClass = [string class];
+		Class nscfStringClass = objc_lookUpClass("__NSCFString");
+		if (stringClass == nscfStringClass || class_getSuperclass(stringClass) == nscfStringClass)
+		{
+			if (enc == kCFStringEncodingInvalidId)
+				enc = CFStringGetSystemEncoding();
+
+			const char *selfCString = CFStringGetCStringPtr(self, enc);
+
+			if (enc == kCFStringEncodingInvalidId)
+				enc = CFStringGetSystemEncoding();
+
+			const char *argCString = CFStringGetCStringPtr(string, enc);
+
+			if (selfCString != NULL && argCString != NULL)
+			{
+				CFIndex length = _CFStringGetLength2(self);
+				if (length == _CFStringGetLength2(string))
+				{
+					return memcmp(selfCString, argCString, length) == 0;
+				}
+				else
+				{
+					return NO;
+				}
+			}
+		}
+	}
+
+	if (![string isNSString__])
+		return NO;
+
+	// Eventually calls __CFStringEqual whose implementation is available at http://opensource.apple.com/source/CF/CF-635.19/CFString.c
+	return CFEqual(self, string);
+}
+
+- (BOOL) isEqualToString:(NSString *)string
+{
+	if (self == string)
+	{
+		return YES;
+	}
+	else if (string == nil)
+	{
+		return NO
+	}
+	else
+	{
+		Class stringClass = [string class];
+		Class nscfStringClass = objc_lookUpClass("__NSCFString");
+		if (stringClass == nscfStringClass || class_getSuperclass(stringClass) == nscfStringClass)
+		{
+			if (enc == kCFStringEncodingInvalidId)
+				enc = CFStringGetSystemEncoding();
+
+			const char *selfCString = CFStringGetCStringPtr(self, enc);
+
+			if (enc == kCFStringEncodingInvalidId)
+				enc = CFStringGetSystemEncoding();
+
+			const char *argCString = CFStringGetCStringPtr(string, enc);
+
+			if (selfCString != NULL && argCString != NULL)
+			{
+				CFIndex length = _CFStringGetLength2(self);
+				if (length == _CFStringGetLength2(string))
+				{
+					return memcmp(selfCString, argCString, length) == 0;
+				}
+				else
+				{
+					return NO;
+				}
+			}
+		}
+	}
+
+	// Eventually calls __CFStringEqual whose implementation is available at http://opensource.apple.com/source/CF/CF-635.19/CFString.c
+	return CFEqual(self, string);
+}
+
 @end
 
 // Foundation.framework 833.24.0 (Mac OS X 10.7.3)
@@ -25,10 +126,10 @@ - (BOOL) isNSString__
 	return YES;
 }
 
-- (BOOL) isEqual:(id)object
+- (BOOL) isEqual:(id)string
 {
-	if ([object isNSString__])
-		return [self isEqualToString:object];
+	if ([string isNSString__])
+		return [self isEqualToString:string];
 	else
 		return NO;
 }

diff --git a/NSString.m b/NSString.m
@@ -0,0 +1,44 @@
+// CoreFoundation.framework 635.19.0 (Mac OS X 10.7.3)
+@implementation NSObject
+
+- (BOOL) isNSString__
+{
+	return NO;
+}
+
+@end
+
+@implementation __NSCFString
+
+- (BOOL) isNSString__
+{
+	return YES;
+}
+
+@end
+
+// Foundation.framework 833.24.0 (Mac OS X 10.7.3)
+@implementation NSString
+
+- (BOOL) isNSString__
+{
+	return YES;
+}
+
+- (BOOL) isEqual:(id)object
+{
+	if ([object isNSString__])
+		return [self isEqualToString:object];
+	else
+		return NO;
+}
+
+- (BOOL) isEqualToString:(NSString *)string
+{
+	if (self == string)
+		return YES;
+	else
+		return [self compare:string options:NSLiteralSearch range:NSMakeRange(0, [self length])] == NSOrderedSame;
+}
+
+@end