2005-09-27 Anthony Balkissoon <abalkiss@redhat.com>

	* javax/swing/text/Utilities.java:
	(getRowEnd): New method.
	(getRowStart): New method.

2 files changed, 97 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index 55fd9385c..f7a483fbc 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2005-09-27  Anthony Balkissoon  <abalkiss@redhat.com>
+
+	* javax/swing/text/Utilities.java:
+	(getRowEnd): New method.
+	(getRowStart): New method.
+
 2005-09-27  Tom Tromey  <tromey@redhat.com>
 
 	* java/beans/beancontext/BeanContextServicesSupport.java
diff --git a/javax/swing/text/Utilities.java b/javax/swing/text/Utilities.java
index 486c8044c..cf1061374 100644
--- a/javax/swing/text/Utilities.java
+++ b/javax/swing/text/Utilities.java
@@ -394,4 +394,95 @@ public class Utilities
     wb.setText(text);
     return wb.following(offs);
   }
+  
+  /**
+   * Get the model position of the end of the row that contains the 
+   * specified model position.  Return null if the given JTextComponent
+   * does not have a size.
+   * @param c the JTextComponent
+   * @param offs the model position
+   * @return the model position of the end of the row containing the given 
+   * offset
+   * @throws BadLocationException if the offset is invalid
+   */
+  public static final int getRowEnd(JTextComponent c, int offs)
+      throws BadLocationException
+  {
+    Element root = c.getDocument().getDefaultRootElement();
+    Element rowElement = root.getElement(root.getElementIndex(offs));
+    String text = c.getText(rowElement.getStartOffset(),
+                            rowElement.getEndOffset());
+    if (text == null)
+      return -1;
+
+    // Do a binary search for the smallest position X > offs
+    // such that that character at positino X is not on the same
+    // line as the character at position offs
+    int high = offs + ((text.length() - 1 - offs) / 2);
+    int low = offs;
+    int oldHigh = text.length();
+    while (true)
+      {
+        if (c.modelToView(high).y != c.modelToView(offs).y)
+          {
+            oldHigh = high;
+            high = low + ((high + 1 - low) / 2);
+            if (oldHigh == high)
+              return high - 1;
+          }
+        else
+          {
+            low = high;
+            high += ((oldHigh - high) / 2);
+            if (low == high)
+              return low;
+          }
+      }
+  }
+      
+  /**
+   * Get the model position of the start of the row that contains the specified
+   * model position. Return null if the given JTextComponent does not have a
+   * size.
+   * 
+   * @param c the JTextComponent
+   * @param offs the model position
+   * @return the model position of the start of the row containing the given
+   *         offset
+   * @throws BadLocationException if the offset is invalid
+   */
+  public static final int getRowStart(JTextComponent c, int offs)
+      throws BadLocationException
+  {
+    Element root = c.getDocument().getDefaultRootElement();
+    Element rowElement = root.getElement(root.getElementIndex(offs));
+    String text = c.getText(rowElement.getStartOffset(),
+                            rowElement.getEndOffset());
+    if (text == null)
+      return -1;
+
+    // Do a binary search for the greatest position X < offs
+    // such that the character at position X is not on the same
+    // row as the character at position offs
+    int high = offs;
+    int low = 0;
+    int oldLow = 0;
+    while (true)
+      {
+        if (c.modelToView(low).y != c.modelToView(offs).y)
+          {
+            oldLow = low;
+            low = high - ((high + 1 - low) / 2);
+            if (oldLow == low)
+              return low + 1;
+          }
+        else
+          {
+            high = low;
+            low -= ((low - oldLow) / 2);
+            if (low == high)
+              return low;
+          }
+      }
+  }
 }