1 files changed, 426 insertions, 0 deletions
diff --git a/core/java/android/text/Selection.java b/core/java/android/text/Selection.java
new file mode 100644
index 0000000..0f4916a
--- /dev/null
+++ b/core/java/android/text/Selection.java
@@ -0,0 +1,426 @@
+/*
+ * Copyright (C) 2006 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.text;
+
+
+/**
+ * Utility class for manipulating cursors and selections in CharSequences.
+ * A cursor is a selection where the start and end are at the same offset.
+ */
+public class Selection {
+    private Selection() { /* cannot be instantiated */ }
+
+    /*
+     * Retrieving the selection
+     */
+
+    /**
+     * Return the offset of the selection anchor or cursor, or -1 if
+     * there is no selection or cursor.
+     */
+    public static final int getSelectionStart(CharSequence text) {
+        if (text instanceof Spanned)
+            return ((Spanned) text).getSpanStart(SELECTION_START);
+        else
+            return -1;
+    }
+   
+    /**
+     * Return the offset of the selection edge or cursor, or -1 if
+     * there is no selection or cursor.
+     */
+    public static final int getSelectionEnd(CharSequence text) {
+        if (text instanceof Spanned)
+            return ((Spanned) text).getSpanStart(SELECTION_END);
+        else
+            return -1;
+    }
+
+    /*
+     * Setting the selection
+     */
+
+    // private static int pin(int value, int min, int max) {
+    //     return value < min ? 0 : (value > max ? max : value);
+    // }
+   
+    /**
+     * Set the selection anchor to <code>start</code> and the selection edge
+     * to <code>stop</code>.
+     */
+    public static void setSelection(Spannable text, int start, int stop) {
+        // int len = text.length();
+        // start = pin(start, 0, len);  XXX remove unless we really need it
+        // stop = pin(stop, 0, len);
+
+        int ostart = getSelectionStart(text);
+        int oend = getSelectionEnd(text);
+    
+        if (ostart != start || oend != stop) {
+            text.setSpan(SELECTION_START, start, start,
+                         Spanned.SPAN_POINT_POINT);
+            text.setSpan(SELECTION_END, stop, stop,
+                         Spanned.SPAN_POINT_POINT);
+        }
+    }
+
+    /**
+     * Move the cursor to offset <code>index</code>.
+     */
+    public static final void setSelection(Spannable text, int index) {
+        setSelection(text, index, index);
+    }
+
+    /**
+     * Select the entire text.
+     */
+    public static final void selectAll(Spannable text) {
+        setSelection(text, 0, text.length());
+    }
+
+    /**
+     * Move the selection edge to offset <code>index</code>.
+     */
+    public static final void extendSelection(Spannable text, int index) {
+        if (text.getSpanStart(SELECTION_END) != index)
+            text.setSpan(SELECTION_END, index, index, Spanned.SPAN_POINT_POINT);
+    }
+
+    /**
+     * Remove the selection or cursor, if any, from the text.
+     */
+    public static final void removeSelection(Spannable text) {
+        text.removeSpan(SELECTION_START);
+        text.removeSpan(SELECTION_END);
+    }
+
+    /*
+     * Moving the selection within the layout
+     */
+
+    /**
+     * Move the cursor to the buffer offset physically above the current
+     * offset, or return false if the cursor is already on the top line.
+     */
+    public static boolean moveUp(Spannable text, Layout layout) {
+        int start = getSelectionStart(text);
+        int end = getSelectionEnd(text);
+
+        if (start != end) {
+            int min = Math.min(start, end);
+            int max = Math.max(start, end);
+
+            setSelection(text, min);
+
+            if (min == 0 && max == text.length()) {
+                return false;
+            }
+
+            return true;
+        } else {
+            int line = layout.getLineForOffset(end);
+
+            if (line > 0) {
+                int move;
+
+                if (layout.getParagraphDirection(line) ==
+                    layout.getParagraphDirection(line - 1)) {
+                    float h = layout.getPrimaryHorizontal(end);
+                    move = layout.getOffsetForHorizontal(line - 1, h);
+                } else {
+                    move = layout.getLineStart(line - 1);
+                }
+
+                setSelection(text, move);
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * Move the cursor to the buffer offset physically below the current
+     * offset, or return false if the cursor is already on the bottom line.
+     */
+    public static boolean moveDown(Spannable text, Layout layout) {
+        int start = getSelectionStart(text);
+        int end = getSelectionEnd(text);
+
+        if (start != end) {
+            int min = Math.min(start, end);
+            int max = Math.max(start, end);
+
+            setSelection(text, max);
+
+            if (min == 0 && max == text.length()) {
+                return false;
+            }
+
+            return true;
+        } else {
+            int line = layout.getLineForOffset(end);
+
+            if (line < layout.getLineCount() - 1) {
+                int move;
+
+                if (layout.getParagraphDirection(line) ==
+                    layout.getParagraphDirection(line + 1)) {
+                    float h = layout.getPrimaryHorizontal(end);
+                    move = layout.getOffsetForHorizontal(line + 1, h);
+                } else {
+                    move = layout.getLineStart(line + 1);
+                }
+
+                setSelection(text, move);
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * Move the cursor to the buffer offset physically to the left of
+     * the current offset, or return false if the cursor is already
+     * at the left edge of the line and there is not another line to move it to.
+     */
+    public static boolean moveLeft(Spannable text, Layout layout) {
+        int start = getSelectionStart(text);
+        int end = getSelectionEnd(text);
+
+        if (start != end) {
+            setSelection(text, chooseHorizontal(layout, -1, start, end));
+            return true;
+        } else {
+            int to = layout.getOffsetToLeftOf(end);
+
+            if (to != end) {
+                setSelection(text, to);
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * Move the cursor to the buffer offset physically to the right of
+     * the current offset, or return false if the cursor is already at
+     * at the right edge of the line and there is not another line
+     * to move it to.
+     */
+    public static boolean moveRight(Spannable text, Layout layout) {
+        int start = getSelectionStart(text);
+        int end = getSelectionEnd(text);
+
+        if (start != end) {
+            setSelection(text, chooseHorizontal(layout, 1, start, end));
+            return true;
+        } else {
+            int to = layout.getOffsetToRightOf(end);
+
+            if (to != end) {
+                setSelection(text, to);
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * Move the selection end to the buffer offset physically above
+     * the current selection end.
+     */
+    public static boolean extendUp(Spannable text, Layout layout) {
+        int end = getSelectionEnd(text);
+        int line = layout.getLineForOffset(end);
+
+        if (line > 0) {
+            int move;
+
+            if (layout.getParagraphDirection(line) ==
+                layout.getParagraphDirection(line - 1)) {
+                float h = layout.getPrimaryHorizontal(end);
+                move = layout.getOffsetForHorizontal(line - 1, h);
+            } else {
+                move = layout.getLineStart(line - 1);
+            }
+
+            extendSelection(text, move);
+            return true;
+        } else if (end != 0) {
+            extendSelection(text, 0);
+            return true;
+        }
+
+        return true;
+    }
+
+    /**
+     * Move the selection end to the buffer offset physically below
+     * the current selection end.
+     */
+    public static boolean extendDown(Spannable text, Layout layout) {
+        int end = getSelectionEnd(text);
+        int line = layout.getLineForOffset(end);
+
+        if (line < layout.getLineCount() - 1) {
+            int move;
+
+            if (layout.getParagraphDirection(line) ==
+                layout.getParagraphDirection(line + 1)) {
+                float h = layout.getPrimaryHorizontal(end);
+                move = layout.getOffsetForHorizontal(line + 1, h);
+            } else {
+                move = layout.getLineStart(line + 1);
+            }
+
+            extendSelection(text, move);
+            return true;
+        } else if (end != text.length()) {
+            extendSelection(text, text.length());
+            return true;
+        }
+
+        return true;
+    }
+
+    /**
+     * Move the selection end to the buffer offset physically to the left of
+     * the current selection end.
+     */
+    public static boolean extendLeft(Spannable text, Layout layout) {
+        int end = getSelectionEnd(text);
+        int to = layout.getOffsetToLeftOf(end);
+
+        if (to != end) {
+            extendSelection(text, to);
+            return true;
+        }
+
+        return true;
+    }
+
+    /**
+     * Move the selection end to the buffer offset physically to the right of
+     * the current selection end.
+     */
+    public static boolean extendRight(Spannable text, Layout layout) {
+        int end = getSelectionEnd(text);
+        int to = layout.getOffsetToRightOf(end);
+
+        if (to != end) {
+            extendSelection(text, to);
+            return true;
+        }
+
+        return true;
+    }
+
+    public static boolean extendToLeftEdge(Spannable text, Layout layout) {
+        int where = findEdge(text, layout, -1);
+        extendSelection(text, where);
+        return true;
+    }
+
+    public static boolean extendToRightEdge(Spannable text, Layout layout) {
+        int where = findEdge(text, layout, 1);
+        extendSelection(text, where);
+        return true;
+    }
+
+    public static boolean moveToLeftEdge(Spannable text, Layout layout) {
+        int where = findEdge(text, layout, -1);
+        setSelection(text, where);
+        return true;
+    }
+
+    public static boolean moveToRightEdge(Spannable text, Layout layout) {
+        int where = findEdge(text, layout, 1);
+        setSelection(text, where);
+        return true;
+    }
+
+    private static int findEdge(Spannable text, Layout layout, int dir) {
+        int pt = getSelectionEnd(text);
+        int line = layout.getLineForOffset(pt);
+        int pdir = layout.getParagraphDirection(line);
+
+        if (dir * pdir < 0) {
+            return layout.getLineStart(line);
+        } else {
+            int end = layout.getLineEnd(line);
+
+            if (line == layout.getLineCount() - 1)
+                return end;
+            else
+                return end - 1;
+        }
+    }
+
+    private static int chooseHorizontal(Layout layout, int direction,
+                                        int off1, int off2) {
+        int line1 = layout.getLineForOffset(off1);
+        int line2 = layout.getLineForOffset(off2);
+
+        if (line1 == line2) {
+            // same line, so it goes by pure physical direction
+
+            float h1 = layout.getPrimaryHorizontal(off1);
+            float h2 = layout.getPrimaryHorizontal(off2);
+
+            if (direction < 0) {
+                // to left
+
+                if (h1 < h2)
+                    return off1;
+                else
+                    return off2;
+            } else {
+                // to right
+
+                if (h1 > h2)
+                    return off1;
+                else
+                    return off2;
+            }
+        } else {
+            // different line, so which line is "left" and which is "right"
+            // depends upon the directionality of the text
+
+            // This only checks at one end, but it's not clear what the
+            // right thing to do is if the ends don't agree.  Even if it
+            // is wrong it should still not be too bad.
+            int line = layout.getLineForOffset(off1);
+            int textdir = layout.getParagraphDirection(line);
+
+            if (textdir == direction)
+                return Math.max(off1, off2);
+            else
+                return Math.min(off1, off2);
+        }
+    }
+
+    /*
+     * Public constants
+     */
+
+    public static final Object SELECTION_START = new Object();
+    public static final Object SELECTION_END = new Object();
+}