1 files changed, 118 insertions, 0 deletions
diff --git a/src/com/android/calculator2/History.java b/src/com/android/calculator2/History.java
new file mode 100644
index 0000000..ff2cc65
--- /dev/null
+++ b/src/com/android/calculator2/History.java
@@ -0,0 +1,118 @@
+/*
+ * Copyright (C) 2008 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 com.android.calculator2;
+
+import android.widget.BaseAdapter;
+
+import java.io.DataInput;
+import java.io.DataOutput;
+import java.io.IOException;
+import java.util.Vector;
+
+class History {
+    private static final int VERSION_1 = 1;
+    private static final int MAX_ENTRIES = 100;
+    Vector<HistoryEntry> mEntries = new Vector<HistoryEntry>();
+    int mPos;
+    BaseAdapter mObserver;
+
+    History() {
+        clear();
+    }
+
+    History(int version, DataInput in) throws IOException {
+        if (version >= VERSION_1) {
+            int size = in.readInt();
+            for (int i = 0; i < size; ++i) {
+                mEntries.add(new HistoryEntry(version, in));
+            }
+            mPos = in.readInt();
+        } else {
+            throw new IOException("invalid version " + version);
+        }
+    }
+
+    void setObserver(BaseAdapter observer) {
+        mObserver = observer;
+    }
+
+    private void notifyChanged() {
+        if (mObserver != null) {
+            mObserver.notifyDataSetChanged();
+        }
+    }
+
+    void clear() {
+        mEntries.clear();
+        mEntries.add(new HistoryEntry(""));
+        mPos = 0;
+        notifyChanged();
+    }
+
+    void write(DataOutput out) throws IOException {
+        out.writeInt(mEntries.size());
+        for (HistoryEntry entry : mEntries) {
+            entry.write(out);
+        }
+        out.writeInt(mPos);
+    }
+
+    void update(String text) {
+        current().setEdited(text);
+    }
+
+    boolean moveToPrevious() {
+        if (mPos > 0) {
+            --mPos;
+            return true;
+        }
+        return false;
+    }
+
+    boolean moveToNext() {
+        if (mPos < mEntries.size() - 1) {
+            ++mPos;
+            return true;
+        }
+        return false;
+    }
+
+    void enter(String text) {
+        current().clearEdited();
+        if (mEntries.size() >= MAX_ENTRIES) {
+            mEntries.remove(0);
+        }
+        if (mEntries.size() < 2 ||
+            !text.equals(mEntries.elementAt(mEntries.size() - 2).getBase())) {
+            mEntries.insertElementAt(new HistoryEntry(text), mEntries.size() - 1);
+        }
+        mPos = mEntries.size() - 1;
+        notifyChanged();
+    }
+
+    HistoryEntry current() {
+        return mEntries.elementAt(mPos);
+    }
+
+    String getText() {
+        return current().getEdited();
+    }
+
+    String getBase() {
+        return current().getBase();
+    }
+}