1 files changed, 91 insertions, 0 deletions
diff --git a/guava/src/com/google/common/primitives/AndroidInteger.java b/guava/src/com/google/common/primitives/AndroidInteger.java
new file mode 100644
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--- /dev/null
+++ b/guava/src/com/google/common/primitives/AndroidInteger.java
@@ -0,0 +1,91 @@
+/*
+ *  Licensed to the Apache Software Foundation (ASF) under one or more
+ *  contributor license agreements.  See the NOTICE file distributed with
+ *  this work for additional information regarding copyright ownership.
+ *  The ASF licenses this file to You 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.google.common.primitives;
+
+import static com.google.common.base.Preconditions.checkArgument;
+import static com.google.common.base.Preconditions.checkNotNull;
+
+import javax.annotation.CheckForNull;
+
+/**
+ * Static utility methods derived from Android's {@code Integer.java}.
+ */
+final class AndroidInteger {
+  /**
+   * See {@link Ints#tryParse(String)} for the public interface.
+   */
+  @CheckForNull
+  static Integer tryParse(String string) {
+    return tryParse(string, 10);
+  }
+
+  /**
+   * See {@link Ints#tryParse(String, int)} for the public interface.
+   */
+  @CheckForNull
+  static Integer tryParse(String string, int radix) {
+    checkNotNull(string);
+    checkArgument(radix >= Character.MIN_RADIX,
+        "Invalid radix %s, min radix is %s", radix, Character.MIN_RADIX);
+    checkArgument(radix <= Character.MAX_RADIX,
+        "Invalid radix %s, max radix is %s", radix, Character.MAX_RADIX);
+    int length = string.length(), i = 0;
+    if (length == 0) {
+      return null;
+    }
+    boolean negative = string.charAt(i) == '-';
+    if (negative && ++i == length) {
+      return null;
+    }
+    return tryParse(string, i, radix, negative);
+  }
+
+  @CheckForNull
+  private static Integer tryParse(String string, int offset, int radix,
+      boolean negative) {
+    int max = Integer.MIN_VALUE / radix;
+    int result = 0, length = string.length();
+    while (offset < length) {
+      int digit = Character.digit(string.charAt(offset++), radix);
+      if (digit == -1) {
+        return null;
+      }
+      if (max > result) {
+        return null;
+      }
+      int next = result * radix - digit;
+      if (next > result) {
+        return null;
+      }
+      result = next;
+    }
+    if (!negative) {
+      result = -result;
+      if (result < 0) {
+        return null;
+      }
+    }
+    // For GWT where ints do not overflow
+    if (result > Integer.MAX_VALUE || result < Integer.MIN_VALUE) {
+      return null;
+    }
+    return result;
+  }
+
+  private AndroidInteger() {}
+}