Styliser method to get string between unstyled indicies

Fixes issue 2199
Unit test for issue 2199

Change-Id: I270fa7265766536f578d5a06c2e3fc274b61e37c
Reviewed-on: http://gerrit.dmdirc.com/753
Reviewed-by: Gregory Holmes <greg@dmdirc.com>
Automatic-Compile: DMDirc Local Commits <dmdirc@googlemail.com>

src/com/dmdirc/ui/messages/Styliser.java

@@ -223,6 +223,44 @@ public class Styliser implements ConfigChangeListener {
         
         return styledDoc;
     }
+
+    /**
+     * Retrieves the styled String contained within the unstyled offsets
+     * specified. That is, the <code>from</code> and <code>to</code> arguments
+     * correspond to indexes in an unstyled version of the <code>styled</code>
+     * string. The unstyled indices are translated to offsets within the
+     * styled String, and the return value includes all text and control codes
+     * between those indices.
+     * <p>
+     * The index translation is left-biased; that is, the indices are translated
+     * to be as far left as they possibly can be. This means that the start of
+     * the string will include any control codes immediately preceeding the
+     * desired text, and the end will not include any trailing codes.
+     *
+     * @param styled The styled String to be operated on
+     * @param from The starting index in the unstyled string
+     * @param to The ending index in the unstyled string
+     * @return The corresponding text between the two indices
+     * @since 0.6.3
+     */
+    public static String getStyledText(final String styled, final int from, final int to) {
+        final String unstyled = stipControlCodes(styled);
+        final String startBit = unstyled.substring(0, from);
+        final String middleBit = unstyled.substring(from, to);
+        int start = from;
+
+        while (!stipControlCodes(styled.substring(0, start)).equals(startBit)) {
+            start++;
+        }
+
+        int end = to + start - from;
+
+        while (!stipControlCodes(styled.substring(start, end)).equals(middleBit)) {
+            end++;
+        }
+
+        return styled.substring(start, end);
+    }
     
     /**
      * Applies the hyperlink styles and intelligent linking regexps to the

test/com/dmdirc/ui/messages/StyliserIndicesTest.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright (c) 2006-2010 Chris Smith, Shane Mc Cormack, Gregory Holmes
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package com.dmdirc.ui.messages;
+
+
+import java.util.Arrays;
+import java.util.List;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+import static org.junit.Assert.*;
+
+@RunWith(Parameterized.class)
+public class StyliserIndicesTest {
+
+    protected String input, output;
+    protected int start, end;
+
+    public StyliserIndicesTest(String input, int start, int end, String output) {
+        this.input = input;
+        this.start = start;
+        this.end = end;
+        this.output = output;
+    }
+       
+    @Test
+    public void testStyle() {
+        assertEquals(output, Styliser.getStyledText(input, start, end));
+    }
+    
+    @Parameterized.Parameters
+    public static List<Object[]> data() {
+        final Object[][] tests = {
+            // No style
+            {"Blah blah blah", 0, 1, "B"},
+            {"Blah blah blah", 0, 4, "Blah"},
+            {Styliser.CODE_BOLD + "Blah blah blah", 0, 4, Styliser.CODE_BOLD + "Blah"},
+            {Styliser.CODE_BOLD + "Bl" + Styliser.CODE_BOLD + "ah blah blah",
+                     0, 4, Styliser.CODE_BOLD + "Bl" + Styliser.CODE_BOLD + "ah"},
+            {"Blah" + Styliser.CODE_BOLD + " blah blah",
+                     0, 4, "Blah"},
+            {"Blah" + Styliser.CODE_COLOUR + "4,0RED blah blah",
+                     4, 7, Styliser.CODE_COLOUR + "4,0RED"},
+        };
+
+        return Arrays.asList(tests);
+    } 
+
+}