1 files changed, 89 insertions, 0 deletions
diff --git a/Userland/Services/TelnetServer/Parser.cpp b/Userland/Services/TelnetServer/Parser.cpp
new file mode 100644
index 0000000000..9fc1aabcd1
--- /dev/null
+++ b/Userland/Services/TelnetServer/Parser.cpp
@@ -0,0 +1,89 @@
+/*
+ * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <AK/Function.h>
+#include <AK/String.h>
+#include <AK/Types.h>
+
+#include "Parser.h"
+
+void Parser::write(const StringView& data)
+{
+    for (size_t i = 0; i < data.length(); i++) {
+        u8 ch = data[i];
+
+        switch (m_state) {
+        case State::Free:
+            switch (ch) {
+            case IAC:
+                m_state = State::ReadCommand;
+                break;
+            case '\r':
+                if (on_data)
+                    on_data("\n");
+                break;
+            default:
+                if (on_data)
+                    on_data(StringView(&ch, 1));
+                break;
+            }
+            break;
+        case State::ReadCommand:
+            switch (ch) {
+            case IAC: {
+                m_state = State::Free;
+                if (on_data)
+                    on_data("\xff");
+                break;
+            }
+            case CMD_WILL:
+            case CMD_WONT:
+            case CMD_DO:
+            case CMD_DONT:
+                m_command = ch;
+                m_state = State::ReadSubcommand;
+                break;
+            default:
+                m_state = State::Error;
+                if (on_error)
+                    on_error();
+                break;
+            }
+            break;
+        case State::ReadSubcommand: {
+            auto command = m_command;
+            m_command = 0;
+            m_state = State::Free;
+            if (on_command)
+                on_command({ command, ch });
+            break;
+        }
+        case State::Error:
+            // ignore everything
+            break;
+        }
+    }
+}