Converted to Swift 3.

Example/Podfile

@@ -1,11 +1,11 @@
 source 'https://github.com/CocoaPods/Specs.git'
 use_frameworks!
 
-target 'SwiftString_Example', :exclusive => true do
+target 'SwiftString_Example' do
   pod 'SwiftString', :path => '../'
 end
 
-target 'SwiftString_Tests', :exclusive => true do
+target 'SwiftString_Tests' do
   pod 'SwiftString', :path => '../'
   pod 'SwiftHamcrest'
 end

Pod/Classes/String+HTML.swift

@@ -270,7 +270,7 @@ public extension String {
     //    decodeNumeric("20ac", 16) --> "€"
     private func decodeNumeric(string : String, base : Int32) -> Character? {
         let code = UInt32(strtoul(string, nil, base))
-        return Character(UnicodeScalar(code))
+        return Character(UnicodeScalar(code)!)
     }
 
     // Decode the HTML character entity to the corresponding
@@ -281,9 +281,11 @@ public extension String {
     //     decode("&foo;")    --> nil
     private func decode(entity : String) -> Character? {
         if entity.hasPrefix("&#x") || entity.hasPrefix("&#X"){
-            return decodeNumeric(entity.substringFromIndex(entity.startIndex.advancedBy(3)), base: 16)
+            let index = entity.index(entity.startIndex, offsetBy: 3)
+            return decodeNumeric(string: entity.substring(from: index), base: 16)
         } else if entity.hasPrefix("&#") {
-            return decodeNumeric(entity.substringFromIndex(entity.startIndex.advancedBy(2)), base: 10)
+            let index = entity.index(entity.startIndex, offsetBy: 2)
+            return decodeNumeric(string: entity.substring(from: index), base: 10)
         } else {
             return HTMLEntities.characterEntities[entity]
         }
@@ -298,29 +300,29 @@ public extension String {
         var position = startIndex
 
         // Find the next '&' and copy the characters preceding it to `result`:
-        while let ampRange = self.rangeOfString("&", range: position ..< endIndex) {
-            result.appendContentsOf(self[position ..< ampRange.startIndex])
-            position = ampRange.startIndex
+        while let ampRange = self.range(of: "&", range: position ..< endIndex) {
+            result.append(self[position ..< ampRange.lowerBound])
+            position = ampRange.lowerBound
 
             // Find the next ';' and copy everything from '&' to ';' into `entity`
-            if let semiRange = self.rangeOfString(";", range: position ..< endIndex) {
-                let entity = self[position ..< semiRange.endIndex]
-                position = semiRange.endIndex
+            if let semiRange = self.range(of: ";", range: position ..< endIndex) {
+                let entity = self[position ..< semiRange.upperBound]
+                position = semiRange.upperBound
 
-                if let decoded = decode(entity) {
+                if let decoded = decode(entity: entity) {
                     // Replace by decoded character:
                     result.append(decoded)
                 } else {
                     // Invalid entity, copy verbatim:
-                    result.appendContentsOf(entity)
+                    result.append(entity)
                 }
             } else {
                 // No matching ';'.
                 break
             }
         }
         // Copy remaining characters to `result`:
-        result.appendContentsOf(self[position ..< endIndex])
+        result.append(self[position ..< endIndex])
         return result
     }
-}
+}