Helper classes for java bindings.

Review URL: https://codereview.chromium.org/288133005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@270757 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 64 insertions, 0 deletions

diff --git a/mojo/bindings/java/src/org/chromium/mojo/bindings/BindingsHelper.java b/mojo/bindings/java/src/org/chromium/mojo/bindings/BindingsHelper.java
new file mode 100644
index 0000000..f2aa046
--- /dev/null
+++ b/mojo/bindings/java/src/org/chromium/mojo/bindings/BindingsHelper.java
@@ -0,0 +1,64 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.mojo.bindings;
+
+/**
+ * Helper functions.
+ */
+public class BindingsHelper {
+    /**
+     * Alignment in byte for mojo serialization.
+     */
+    public static final int ALIGNMENT = 8;
+
+    /**
+     * Align |size| on {@link BindingsHelper#ALIGNMENT}.
+     */
+    public static int align(int size) {
+        return (size + ALIGNMENT - 1) & ~(ALIGNMENT - 1);
+    }
+
+    /**
+     * Compute the size in bytes of the given string encoded as utf8.
+     */
+    public static int utf8StringSizeInBytes(String s) {
+        int res = 0;
+        for (int i = 0; i < s.length(); ++i) {
+            char c = s.charAt(i);
+            int codepoint = c;
+            if (isSurrogate(c)) {
+                i++;
+                char c2 = s.charAt(i);
+                codepoint = Character.toCodePoint(c, c2);
+            }
+            res += 1;
+            if (codepoint > 0x7f) {
+                res += 1;
+                if (codepoint > 0x7ff) {
+                    res += 1;
+                    if (codepoint > 0xffff) {
+                        res += 1;
+                        if (codepoint > 0x1fffff) {
+                            res += 1;
+                            if (codepoint > 0x3ffffff) {
+                                res += 1;
+                            }
+                        }
+                    }
+                }
+            }
+        }
+        return res;
+    }
+
+    /**
+     * Determines if the given {@code char} value is a Unicode <i>surrogate code unit</i>. See
+     * {@link Character#isSurrogate}. Extracting here because the method only exists at API level
+     * 19.
+     */
+    private static boolean isSurrogate(char c) {
+        return c >= Character.MIN_SURROGATE && c < (Character.MAX_SURROGATE + 1);
+    }
+}