Implement JSON parsing and serialization.

This will be used by the upcoming Open vSwitch configuration database.

lib/unicode.c

@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2009 Nicira Networks.
+ *
+ * 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.
+ */
+
+#include <config.h>
+
+#include "unicode.h"
+
+/* Returns the unicode code point corresponding to leading surrogate 'leading'
+ * and trailing surrogate 'trailing'.  The return value will not make any
+ * sense if 'leading' or 'trailing' are not in the correct ranges for leading
+ * or trailing surrogates. */
+int
+utf16_decode_surrogate_pair(int leading, int trailing)
+{
+    /*
+     *  Leading surrogate:         110110wwwwxxxxxx
+     * Trailing surrogate:         110111xxxxxxxxxx
+     *         Code point: 000uuuuuxxxxxxxxxxxxxxxx
+     */
+    int w = (leading >> 6) & 0xf;
+    int u = w + 1;
+    int x0 = leading & 0x3f;
+    int x1 = trailing & 0x3ff;
+    return (u << 16) | (x0 << 10) | x1;
+}