From 116faff062127d5ec61b17158676f0541df9e03c Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Sun, 22 Jan 2017 20:16:51 -0500
Subject: [PATCH] add CommandParser class

---
 src/core/CommandParser.cc | 74 +++++++++++++++++++++++++++++++++++++++
 src/core/CommandParser.h  | 30 ++++++++++++++++
 2 files changed, 104 insertions(+)
 create mode 100644 src/core/CommandParser.cc
 create mode 100644 src/core/CommandParser.h

diff --git a/src/core/CommandParser.cc b/src/core/CommandParser.cc
new file mode 100644
index 0000000..095e1ef
--- /dev/null
+++ b/src/core/CommandParser.cc
@@ -0,0 +1,74 @@
+#include "CommandParser.h"
+
+bool CommandParser::parse(const EncodedString & command)
+{
+    std::vector<uint8_t> current_arg;
+    EncodedString::iterator end = command.end();
+    EncodedString::iterator it = command.begin();
+    uint32_t quote = 0u;
+    bool arg_content = false;
+    auto append_char = [&current_arg, &it, &command, &arg_content]() {
+        size_t offset = it.offset();
+        for (size_t i = 0u, sz = it.size(); i < sz; i++)
+        {
+            current_arg.push_back(command[offset + i]);
+        }
+        arg_content = true;
+    };
+    auto collect_arg = [this, &current_arg, &arg_content] {
+        if (arg_content)
+        {
+            m_args.push_back(std::make_shared<EncodedString>(&current_arg[0], current_arg.size()));
+            current_arg.clear();
+            arg_content = false;
+        }
+        arg_content = false;
+    };
+    while (it != end)
+    {
+        uint32_t cp = *it;
+        if ((quote != 0u) && (cp == quote))
+        {
+            quote = 0u;
+            ++it;
+            continue;
+        }
+        if ((quote == 0u) && ((cp == '\'') || (cp == '"')))
+        {
+            quote = cp;
+            ++it;
+            continue;
+        }
+        if (cp == '\\')
+        {
+            if (++it == end)
+            {
+                m_parse_error = "Unterminated escape sequence";
+                return false;
+            }
+            append_char();
+            ++it;
+            continue;
+        }
+        else if (cp == ' ')
+        {
+            collect_arg();
+        }
+        else
+        {
+            append_char();
+            ++it;
+            continue;
+        }
+    }
+
+    if (quote != 0u)
+    {
+        m_parse_error = std::string("Unterminated quoted region");
+        return false;
+    }
+
+    collect_arg();
+
+    return true;
+}
diff --git a/src/core/CommandParser.h b/src/core/CommandParser.h
new file mode 100644
index 0000000..8ec455d
--- /dev/null
+++ b/src/core/CommandParser.h
@@ -0,0 +1,30 @@
+#ifndef COMMANDPARSER_H
+#define COMMANDPARSER_H
+
+#include <vector>
+#include <string>
+#include "EncodedString.h"
+
+class CommandParser
+{
+public:
+    bool parse(const EncodedString & command);
+    std::shared_ptr<EncodedString> operator[](size_t index) const
+    {
+        return m_args[index];
+    }
+    size_t size() const
+    {
+        return m_args.size();
+    }
+    const std::string & parse_error() const
+    {
+        return m_parse_error;
+    }
+
+protected:
+    std::vector<std::shared_ptr<EncodedString>> m_args;
+    std::string m_parse_error;
+};
+
+#endif