Merged in feature/from-pantheon (pull request #16)

code from pantheon

* code from pantheon

wp/wp-includes/sodium_compat/lib/stream-xchacha20.php

@@ -0,0 +1,59 @@
+<?php
+
+if (!is_callable('sodium_crypto_stream_xchacha20')) {
+    /**
+     * @see ParagonIE_Sodium_Compat::crypto_stream_xchacha20()
+     * @param int $len
+     * @param string $nonce
+     * @param string $key
+     * @return string
+     * @throws SodiumException
+     * @throws TypeError
+     */
+    function sodium_crypto_stream_xchacha20($len, $nonce, $key)
+    {
+        return ParagonIE_Sodium_Compat::crypto_stream_xchacha20($len, $nonce, $key, true);
+    }
+}
+if (!is_callable('sodium_crypto_stream_xchacha20_keygen')) {
+    /**
+     * @see ParagonIE_Sodium_Compat::crypto_stream_xchacha20_keygen()
+     * @return string
+     * @throws Exception
+     */
+    function sodium_crypto_stream_xchacha20_keygen()
+    {
+        return ParagonIE_Sodium_Compat::crypto_stream_xchacha20_keygen();
+    }
+}
+if (!is_callable('sodium_crypto_stream_xchacha20_xor')) {
+    /**
+     * @see ParagonIE_Sodium_Compat::crypto_stream_xchacha20_xor()
+     * @param string $message
+     * @param string $nonce
+     * @param string $key
+     * @return string
+     * @throws SodiumException
+     * @throws TypeError
+     */
+    function sodium_crypto_stream_xchacha20_xor($message, $nonce, $key)
+    {
+        return ParagonIE_Sodium_Compat::crypto_stream_xchacha20_xor($message, $nonce, $key, true);
+    }
+}
+if (!is_callable('sodium_crypto_stream_xchacha20_xor_ic')) {
+    /**
+     * @see ParagonIE_Sodium_Compat::crypto_stream_xchacha20_xor_ic()
+     * @param string $message
+     * @param string $nonce
+     * @param int $counter
+     * @param string $key
+     * @return string
+     * @throws SodiumException
+     * @throws TypeError
+     */
+    function sodium_crypto_stream_xchacha20_xor_ic($message, $nonce, $counter, $key)
+    {
+        return ParagonIE_Sodium_Compat::crypto_stream_xchacha20_xor_ic($message, $nonce, $counter, $key, true);
+    }
+}