Modernize ObjC

GCDWebServer/Core/GCDWebServerFunctions.h

@@ -27,6 +27,8 @@
 
 #import <Foundation/Foundation.h>
 
+NS_ASSUME_NONNULL_BEGIN
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -42,12 +44,12 @@ NSString* GCDWebServerGetMimeTypeForExtension(NSString* extension);
  *  The legal characters ":@/?&=+" are also escaped to ensure compatibility
  *  with URL encoded forms and URL queries.
  */
-NSString* GCDWebServerEscapeURLString(NSString* string);
+NSString* _Nullable GCDWebServerEscapeURLString(NSString* string);
 
 /**
  *  Unescapes a URL percent-encoded string.
  */
-NSString* GCDWebServerUnescapeURLString(NSString* string);
+NSString* _Nullable GCDWebServerUnescapeURLString(NSString* string);
 
 /**
  *  Extracts the unescaped names and values from an
@@ -63,7 +65,7 @@ NSDictionary* GCDWebServerParseURLEncodedForm(NSString* form);
  *  On iOS, returns the IPv4 or IPv6 address as a string of the WiFi
  *  interface if connected or nil otherwise.
  */
-NSString* GCDWebServerGetPrimaryIPAddress(BOOL useIPv6);
+NSString* _Nullable GCDWebServerGetPrimaryIPAddress(BOOL useIPv6);
 
 /**
  *  Converts a date into a string using RFC822 formatting.
@@ -79,7 +81,7 @@ NSString* GCDWebServerFormatRFC822(NSDate* date);
  *
  *  @warning Timezones other than GMT are not supported by this function.
  */
-NSDate* GCDWebServerParseRFC822(NSString* string);
+NSDate* _Nullable GCDWebServerParseRFC822(NSString* string);
 
 /**
  *  Converts a date into a string using IOS 8601 formatting.
@@ -94,8 +96,10 @@ NSString* GCDWebServerFormatISO8601(NSDate* date);
  *  @warning Only "calendar" variant is supported at this time and timezones
  *  other than GMT are not supported either.
  */
-NSDate* GCDWebServerParseISO8601(NSString* string);
+NSDate* _Nullable GCDWebServerParseISO8601(NSString* string);
 
 #ifdef __cplusplus
 }
 #endif
+
+NS_ASSUME_NONNULL_END