Optimisation for String and XML parsing.

modules/juce_core/text/juce_String.cpp

@@ -605,6 +605,30 @@ void String::append (const String& textToAppend, size_t maxCharsToTake)
     appendCharPointer (textToAppend.text, maxCharsToTake);
 }
 
+void String::appendCharPointer (const CharPointerType textToAppend)
+{
+    appendCharPointer (textToAppend, textToAppend.findTerminatingNull());
+}
+
+void String::appendCharPointer (const CharPointerType startOfTextToAppend,
+                                const CharPointerType endOfTextToAppend)
+{
+    jassert (startOfTextToAppend.getAddress() != nullptr && endOfTextToAppend.getAddress() != nullptr);
+    jassert (startOfTextToAppend.getAddress() <= endOfTextToAppend.getAddress());
+
+    const size_t extraBytesNeeded = endOfTextToAppend.getAddress() - startOfTextToAppend.getAddress();
+
+    if (extraBytesNeeded > 0)
+    {
+        const size_t byteOffsetOfNull = getByteOffsetOfEnd();
+        preallocateBytes (byteOffsetOfNull + extraBytesNeeded);
+
+        char* const newStringStart = addBytesToPointer (text.getAddress(), (int) byteOffsetOfNull);
+        memcpy (newStringStart, startOfTextToAppend.getAddress(), extraBytesNeeded);
+        CharPointerType (newStringStart + extraBytesNeeded).writeNull();
+    }
+}
+
 String& String::operator+= (const wchar_t* const t)
 {
     appendCharPointer (castToCharPointer_wchar_t (t));
@@ -628,7 +652,7 @@ String& String::operator+= (const char* const t)
     */
     jassert (t == nullptr || CharPointer_ASCII::isValidString (t, std::numeric_limits<int>::max()));
 
-    appendCharPointer (CharPointer_ASCII (t));
+    appendCharPointer (CharPointer_UTF8 (t)); // (using UTF8 here triggers a faster code-path than ascii)
     return *this;
 }
 

modules/juce_core/text/juce_String.h

@@ -217,6 +217,17 @@ public:
     */
     void append (const String& textToAppend, size_t maxCharsToTake);
 
+    /** Appends a string to the end of this one.
+
+        @param startOfTextToAppend  the start of the string to add. This must not be a nullptr
+        @param endOfTextToAppend    the end of the string to add. This must not be a nullptr
+    */
+    void appendCharPointer (const CharPointerType startOfTextToAppend,
+                            const CharPointerType endOfTextToAppend);
+
+    /** Appends a string to the end of this one. */
+    void appendCharPointer (const CharPointerType textToAppend);
+
     /** Appends a string to the end of this one.
 
         @param textToAppend     the string to add

modules/juce_core/xml/juce_XmlDocument.cpp

@@ -326,7 +326,6 @@ void XmlDocument::readQuotedString (String& result)
         else
         {
             const String::CharPointerType start (input);
-            size_t numChars = 0;
 
             for (;;)
             {
@@ -334,13 +333,13 @@ void XmlDocument::readQuotedString (String& result)
 
                 if (character == quote)
                 {
-                    result.appendCharPointer (start, numChars);
+                    result.appendCharPointer (start, input);
                     ++input;
                     return;
                 }
                 else if (character == '&')
                 {
-                    result.appendCharPointer (start, numChars);
+                    result.appendCharPointer (start, input);
                     break;
                 }
                 else if (character == 0)
@@ -351,7 +350,6 @@ void XmlDocument::readQuotedString (String& result)
                 }
 
                 ++input;
-                ++numChars;
             }
         }
     }
@@ -582,17 +580,15 @@ void XmlDocument::readChildElements (XmlElement* parent)
                 else
                 {
                     const String::CharPointerType start (input);
-                    size_t len = 0;
 
                     for (;;)
                     {
                         const juce_wchar nextChar = *input;
 
                         if (nextChar == '<' || nextChar == '&')
-                        {
                             break;
-                        }
-                        else if (nextChar == 0)
+
+                        if (nextChar == 0)
                         {
                             setLastError ("unmatched tags", false);
                             outOfData = true;
@@ -600,17 +596,14 @@ void XmlDocument::readChildElements (XmlElement* parent)
                         }
 
                         ++input;
-                        ++len;
                     }
 
-                    textElementContent.appendCharPointer (start, len);
+                    textElementContent.appendCharPointer (start, input);
                 }
             }
 
             if ((! ignoreEmptyTextElements) || textElementContent.containsNonWhitespaceChars())
-            {
                 childAppender.append (XmlElement::createTextElement (textElementContent));
-            }
         }
     }
 }