Added a JSON-RPC module that can be used by other modules to provide a remote

procedure call interface. This should work in theory, but does not for me.
But then, neither does m_httpd_stats so it's probably me...


git-svn-id: http://svn.inspircd.org/repository/trunk/inspircd@7460 e03df62e-2008-0410-955e-edbf42e46eb7

2 files changed, 2644 insertions, 0 deletions

diff --git a/src/modules/json.h b/src/modules/json.h
new file mode 100644
index 000000000..c9fc5c4ff
--- /dev/null
+++ b/src/modules/json.h
@@ -0,0 +1,535 @@
+#ifndef JSON_H
+#define JSON_H
+
+#include <string>
+#include <vector>
+#include <map>
+#include <deque>
+#include <stack>
+
+#if __GNUC__ >= 3
+# define maybe_expect(expr,value)       __builtin_expect ((expr),(value))
+# define is_const(expr)                 __builtin_constant_p ((expr))
+#else
+# define maybe_expect(expr,value)       (expr)
+# define is_const(expr)                 0
+#endif
+
+#define expect_false(expr) maybe_expect ((expr) != 0, 0)
+#define expect_true(expr)  maybe_expect ((expr) != 0, 1)
+
+static void unreachable_internal (char const *file, int line, char const *function);
+static void throw_unless_internal (char const *file, int line, char const *function, char const *condition);
+static void throw_msg_unless_internal (char const *file, int line, char const *function, char const *message);
+
+#define throw_unreachable                       unreachable_internal (__FILE__, __LINE__, __PRETTY_FUNCTION__)
+#define throw_unless(condition)                 if (!expect_false (condition)) throw_unless_internal (__FILE__, __LINE__, __PRETTY_FUNCTION__, #condition)
+#define throw_msg_unless(condition, message)    if (!expect_false (condition)) throw_msg_unless_internal (__FILE__, __LINE__, __PRETTY_FUNCTION__, message)
+
+namespace json
+{
+  class ValueIterator;
+  class ValueConstIterator;
+
+  enum ValueType
+    {
+      nullValue = 0,
+      intValue,
+      uintValue,
+      realValue,
+      stringValue,
+      booleanValue,
+      arrayValue,
+      objectValue
+    };
+
+  class StaticString
+  {
+  public:
+    explicit StaticString (char const *czstring)
+      : str_ (czstring)
+    {
+    }
+
+    operator char const *() const
+    {
+      return str_;
+    }
+
+    char const *c_str() const
+    {
+      return str_;
+    }
+
+  private:
+    char const *str_;
+  };
+
+  class Value 
+  {
+    friend class ValueIteratorBase;
+  public:
+    typedef std::vector<std::string> Members;
+    typedef ValueIterator iterator;
+    typedef ValueConstIterator const_iterator;
+    typedef unsigned ArrayIndex;
+
+    static const Value null;
+    static const int minInt;
+    static const int maxInt;
+    static const unsigned maxUInt;
+
+  private:
+    class CZString 
+    {
+    public:
+      enum DuplicationPolicy 
+        {
+          noDuplication = 0,
+          duplicate,
+          duplicateOnCopy
+        };
+      CZString (int index);
+      CZString (char const *cstr, DuplicationPolicy allocate);
+      CZString (const CZString &other);
+      ~CZString ();
+      CZString &operator = (const CZString &other);
+      bool operator < (const CZString &other) const;
+      bool operator == (const CZString &other) const;
+      int index () const;
+      char const *c_str () const;
+      bool isStaticString () const;
+    private:
+      void swap (CZString &other);
+      char const *cstr_;
+      int index_;
+    };
+
+  public:
+    typedef std::map<CZString, Value> ObjectValues;
+
+  public:
+    Value (ValueType type = nullValue);
+    Value (int value);
+    Value (unsigned value);
+    Value (double value);
+    Value (char const *value);
+    Value (const StaticString &value);
+    Value (const std::string &value);
+    Value (bool value);
+    Value (const Value &other);
+    ~Value ();
+
+    Value &operator = (const Value &other);
+
+    void swap (Value &other);
+
+    ValueType type () const;
+
+    bool operator < (const Value &other) const;
+    bool operator <= (const Value &other) const;
+    bool operator >= (const Value &other) const;
+    bool operator > (const Value &other) const;
+
+    bool operator == (const Value &other) const;
+    bool operator != (const Value &other) const;
+
+    operator char const * () const;
+    operator std::string () const;
+    operator int () const;
+    operator unsigned () const;
+    operator double () const;
+    operator bool () const;
+
+    bool isNull () const;
+    bool isBool () const;
+    bool isInt () const;
+    bool isUInt () const;
+    bool isIntegral () const;
+    bool isDouble () const;
+    bool isNumeric () const;
+    bool isString () const;
+    bool isArray () const;
+    bool isObject () const;
+
+    bool isConvertibleTo (ValueType other) const;
+
+    unsigned size () const;
+
+    bool empty () const;
+
+    bool operator ! () const;
+
+    void clear ();
+
+    void resize (unsigned size);
+
+    Value &operator [] (int index);
+    Value &operator [] (unsigned index);
+    const Value &operator [] (int index) const;
+    const Value &operator [] (unsigned index) const;
+    Value get (int index, const Value &defaultValue) const;
+    Value get (unsigned index, const Value &defaultValue) const;
+    bool isValidIndex (int index) const;
+    bool isValidIndex (unsigned index) const;
+
+    Value &append (const Value &value);
+
+    Value &operator [] (char const *key);
+    const Value &operator [] (char const *key) const;
+    Value &operator [] (const std::string &key);
+    const Value &operator [] (const std::string &key) const;
+    Value &operator [] (const StaticString &key);
+    Value get (char const *key, const Value &defaultValue) const;
+    Value get (const std::string &key, const Value &defaultValue) const;
+    Value removeMember (char const* key);
+    Value removeMember (const std::string &key);
+
+    bool isMember (char const *key) const;
+    bool isMember (const std::string &key) const;
+
+    Members getMemberNames () const;
+
+    const_iterator begin () const;
+    const_iterator end () const;
+
+    iterator begin ();
+    iterator end ();
+
+  private:
+    Value &resolveReference (char const *key, bool isStatic);
+
+    struct MemberNamesTransform
+    {
+      typedef char const *result_type;
+      char const *operator () (const CZString &name) const
+      {
+        return name.c_str ();
+      }
+    };
+
+    union ValueHolder
+    {
+      int               int_;
+      unsigned          uint_;
+      double            real_;
+      bool              bool_;
+      char              *string_;
+      ObjectValues      *map_;
+    } value_;
+
+    ValueType   type_      : 8;
+    int         allocated_ : 1;
+  };
+
+
+  class ValueAllocator
+  {
+  public:
+    enum { unknown = (unsigned)-1 };
+
+    virtual ~ValueAllocator ();
+
+    virtual char *makeMemberName (char const *memberName) = 0;
+    virtual void releaseMemberName (char *memberName) = 0;
+    virtual char *duplicateStringValue (char const *value, 
+                                        unsigned length = unknown) = 0;
+    virtual void releaseStringValue (char *value) = 0;
+  };
+
+  class ValueIteratorBase
+  {
+  public:
+    typedef unsigned size_t;
+    typedef int difference_type;
+    typedef ValueIteratorBase SelfType;
+
+    ValueIteratorBase ();
+    explicit ValueIteratorBase (const Value::ObjectValues::iterator &current);
+
+    bool operator == (const SelfType &other) const
+    {
+      return isEqual (other);
+    }
+
+    bool operator != (const SelfType &other) const
+    {
+      return !isEqual (other);
+    }
+
+    difference_type operator - (const SelfType &other) const
+    {
+      return computeDistance (other);
+    }
+
+    Value key () const;
+
+    unsigned index () const;
+
+    char const *memberName () const;
+
+  protected:
+    Value &deref () const;
+
+    void increment ();
+
+    void decrement ();
+
+    difference_type computeDistance (const SelfType &other) const;
+
+    bool isEqual (const SelfType &other) const;
+
+    void copy (const SelfType &other);
+
+  private:
+    Value::ObjectValues::iterator current_;
+  };
+
+  class ValueConstIterator : public ValueIteratorBase
+  {
+    friend class Value;
+  public:
+    typedef unsigned size_t;
+    typedef int difference_type;
+    typedef const Value &reference;
+    typedef const Value *pointer;
+    typedef ValueConstIterator SelfType;
+
+    ValueConstIterator ();
+  private:
+    explicit ValueConstIterator (const Value::ObjectValues::iterator &current);
+  public:
+    SelfType &operator = (const ValueIteratorBase &other);
+
+    SelfType operator ++ (int)
+    {
+      SelfType temp (*this);
+      ++*this;
+      return temp;
+    }
+
+    SelfType operator -- (int)
+    {
+      SelfType temp (*this);
+      --*this;
+      return temp;
+    }
+
+    SelfType &operator -- ()
+    {
+      decrement ();
+      return *this;
+    }
+
+    SelfType &operator ++ ()
+    {
+      increment ();
+      return *this;
+    }
+
+    reference operator * () const
+    {
+      return deref ();
+    }
+  };
+
+
+  class ValueIterator : public ValueIteratorBase
+  {
+    friend class Value;
+  public:
+    typedef unsigned size_t;
+    typedef int difference_type;
+    typedef Value &reference;
+    typedef Value *pointer;
+    typedef ValueIterator SelfType;
+
+    ValueIterator ();
+    ValueIterator (const ValueConstIterator &other);
+    ValueIterator (const ValueIterator &other);
+
+  private:
+    explicit ValueIterator (const Value::ObjectValues::iterator &current);
+
+  public:
+
+    SelfType &operator = (const SelfType &other);
+
+    SelfType operator ++ (int)
+    {
+      SelfType temp (*this);
+      ++*this;
+      return temp;
+    }
+
+    SelfType operator -- (int)
+    {
+      SelfType temp (*this);
+      --*this;
+      return temp;
+    }
+
+    SelfType &operator -- ()
+    {
+      decrement ();
+      return *this;
+    }
+
+    SelfType &operator ++ ()
+    {
+      increment ();
+      return *this;
+    }
+
+    reference operator * () const
+    {
+      return deref ();
+    }
+  };
+} // namespace json
+
+namespace json
+{
+  class Value;
+
+  class Reader
+  {
+  public:
+    typedef char const *Location;
+
+    Reader ();
+
+    bool parse (const std::string &document, Value &root);
+    bool parse (char const *beginDoc, char const *endDOc, Value &root);
+    bool parse (std::istream &, Value &root);
+
+    std::string error_msgs () const;
+
+  private:
+    enum TokenType
+      {
+        tokenEndOfStream = 0,
+        tokenObjectBegin,
+        tokenObjectEnd,
+        tokenArrayBegin,
+        tokenArrayEnd,
+        tokenString,
+        tokenNumber,
+        tokenTrue,
+        tokenFalse,
+        tokenNull,
+        tokenArraySeparator,
+        tokenMemberSeparator,
+        tokenComment,
+        tokenError
+      };
+
+    class Token
+    {
+    public:
+      TokenType type_;
+      Location start_;
+      Location end_;
+    };
+
+    class ErrorInfo
+    {
+    public:
+      Token token_;
+      std::string message_;
+      Location extra_;
+    };
+
+    typedef std::deque<ErrorInfo> Errors;
+
+    bool expectToken (TokenType type, Token &token, char const *message);
+    bool readToken (Token &token);
+    void skipSpaces ();
+    bool match (Location pattern, 
+                int patternLength);
+    bool readString ();
+    void readNumber ();
+    bool readValue ();
+    bool readObject ();
+    bool readArray ();
+    bool decodeNumber (Token &token);
+    bool decodeString (Token &token);
+    bool decodeString (Token &token, std::string &decoded);
+    bool decodeDouble (Token &token);
+    bool decodeUnicodeEscapeSequence (Token &token, 
+                                      Location &current, 
+                                      Location end, 
+                                      unsigned &unicode);
+    bool addError (const std::string &message, 
+                   Token &token,
+                   Location extra = 0);
+    bool recoverFromError (TokenType skipUntilToken);
+    bool addErrorAndRecover (const std::string &message, 
+                             Token &token,
+                             TokenType skipUntilToken);
+    void skipUntilSpace ();
+    Value &currentValue ();
+    char getNextChar ();
+    void getLocationLineAndColumn (Location location,
+                                   int &line,
+                                   int &column) const;
+    std::string getLocationLineAndColumn (Location location) const;
+   
+    typedef std::stack<Value *> Nodes;
+    Nodes nodes_;
+    Errors errors_;
+    std::string document_;
+    Location begin_;
+    Location end_;
+    Location current_;
+    Location lastValueEnd_;
+    Value *lastValue_;
+  };
+
+  std::istream& operator >> (std::istream&, Value&);
+
+} // namespace json
+
+namespace json
+{
+  class Value;
+
+  class Writer
+  {
+  public:
+    Writer () { }
+    ~Writer () { }
+
+  public:
+    std::string write (const Value &root);
+
+  private:
+    void writeValue (const Value &value);
+
+    std::string document_;
+  };
+
+  std::string valueToString (int value);
+  std::string valueToString (unsigned value);
+  std::string valueToString (double value);
+  std::string valueToString (bool value);
+  std::string valueToQuotedString (char const *value);
+} // namespace json
+
+/*
+ * JSON-RPC implementation in C++
+ */
+
+namespace json
+{
+  namespace rpc
+  {
+    typedef void (*method) (HTTPRequest *http, Value &request, Value &response);
+    void init (void);
+    void add_method (char *name, method mth);
+    void service (HTTPRequest *http, Value &request, Value &response);
+    void process (HTTPRequest *http, std::string &response, char const *request);
+  }
+}
+
+#endif // JSON_H
diff --git a/src/modules/m_rpc_json.cpp b/src/modules/m_rpc_json.cpp
new file mode 100644
index 000000000..6d9b024f9
--- /dev/null
+++ b/src/modules/m_rpc_json.cpp
@@ -0,0 +1,2109 @@
+/*       +------------------------------------+
+ *       | Inspire Internet Relay Chat Daemon |
+ *       +------------------------------------+
+ *
+ *  InspIRCd: (C) 2002-2007 InspIRCd Development Team
+ * See: http://www.inspircd.org/wiki/index.php/Credits
+ *
+ * This program is free but copyrighted software; see
+ *	    the file COPYING for details.
+ *
+ * ---------------------------------------------------
+ */
+
+#include <cstddef>
+#include <cstdio>
+#include <iostream>
+#include <stdexcept>
+#include <utility>
+
+#include "inspircd.h"
+#include "users.h"
+#include "channels.h"
+#include "configreader.h"
+#include "modules.h"
+#include "inspsocket.h"
+#include "httpd.h"
+#include "json.h"
+
+/* $ModDesc: Provides a JSON-RPC interface for modules using m_httpd.so */
+
+class ModuleRpcJson : public Module
+{
+ public:
+	ModuleRpcJson(InspIRCd* Me) : Module(Me)
+	{
+		json::rpc::init ();
+	}
+
+	void OnEvent(Event* event)
+	{
+		std::stringstream data("");
+
+		if (event->GetEventID() == "httpd_url")
+		{
+			HTTPRequest* http = (HTTPRequest*)event->GetData();
+
+			if (http->GetURI() == "/jsonrpc" && http->GetType() == "POST")
+			{
+				std::string response_text;
+				json::rpc::process (http, response_text, http->GetPostData().c_str());
+				data << response_text;
+
+				/* Send the document back to m_httpd */
+				HTTPDocument response(http->sock, &data, 200, "X-Powered-By: m_rpc_json.so\r\n"
+									      "Content-Type: application/json; charset=iso-8859-1\r\n");
+				Request req((char*)&response, (Module*)this, event->GetSource());
+				req.Send();
+			}
+		}
+	}
+
+	void Implements(char* List)
+	{
+		List[I_OnEvent] = 1;
+	}
+
+	virtual ~ModuleRpcJson()
+	{
+	}
+
+	virtual Version GetVersion()
+	{
+		return Version(0, 1, 0, 0, VF_VENDOR, API_VERSION);
+	}
+};
+
+static void
+unreachable_internal (char const *file, int line, char const *function)
+{
+  char buf[1024];
+  snprintf (buf, 1024, "%s (%d) [%s] critical: Unreachable line reached.",
+	    file, line, function);
+
+  throw std::runtime_error (buf);
+}
+
+static void
+throw_unless_internal (char const *file, int line, char const *function, char const *condition)
+{
+  char buf[1024];
+  snprintf (buf, 1024, "%s (%d) [%s] critical: Assertion `%s' failed.",
+	    file, line, function, condition);
+
+  throw std::runtime_error (buf);
+}
+
+static void
+throw_msg_unless_internal (char const *file, int line, char const *function, char const *message)
+{
+  char buf[1024];
+  snprintf (buf, 1024, "%s (%d) [%s] critical: %s.",
+	    file, line, function, message);
+
+  throw std::runtime_error (buf);
+}
+
+
+namespace json
+{
+  ValueIteratorBase::ValueIteratorBase ()
+  {
+  }
+
+
+  ValueIteratorBase::ValueIteratorBase (const Value::ObjectValues::iterator &current)
+    : current_ (current)
+  {
+  }
+
+  Value &
+  ValueIteratorBase::deref () const
+  {
+    return current_->second;
+  }
+
+
+  void 
+  ValueIteratorBase::increment ()
+  {
+    ++current_;
+  }
+
+
+  void 
+  ValueIteratorBase::decrement ()
+  {
+    --current_;
+  }
+
+
+  ValueIteratorBase::difference_type 
+  ValueIteratorBase::computeDistance (const SelfType &other) const
+  {
+    return difference_type (std::distance (current_, other.current_));
+  }
+
+
+  bool 
+  ValueIteratorBase::isEqual (const SelfType &other) const
+  {
+    return current_ == other.current_;
+  }
+
+
+  void 
+  ValueIteratorBase::copy (const SelfType &other)
+  {
+    current_ = other.current_;
+  }
+
+
+  Value 
+  ValueIteratorBase::key () const
+  {
+    const Value::CZString czstring = (*current_).first;
+    if (czstring.c_str ())
+      {
+	if (czstring.isStaticString ())
+	  return Value (StaticString (czstring.c_str ()));
+	return Value (czstring.c_str ());
+      }
+    return Value (czstring.index ());
+  }
+
+
+  unsigned 
+  ValueIteratorBase::index () const
+  {
+    const Value::CZString czstring = (*current_).first;
+    if (!czstring.c_str ())
+      return czstring.index ();
+    return unsigned (-1);
+  }
+
+
+  char const *
+  ValueIteratorBase::memberName () const
+  {
+    char const *name = (*current_).first.c_str ();
+    return name ? name : "";
+  }
+
+
+  ValueConstIterator::ValueConstIterator ()
+  {
+  }
+
+
+  ValueConstIterator::ValueConstIterator (const Value::ObjectValues::iterator &current)
+    : ValueIteratorBase (current)
+  {
+  }
+
+  ValueConstIterator &
+  ValueConstIterator::operator = (const ValueIteratorBase &other)
+  {
+    copy (other);
+    return *this;
+  }
+
+
+  ValueIterator::ValueIterator ()
+  {
+  }
+
+
+  ValueIterator::ValueIterator (const Value::ObjectValues::iterator &current)
+    : ValueIteratorBase (current)
+  {
+  }
+
+  ValueIterator::ValueIterator (const ValueConstIterator &other)
+    : ValueIteratorBase (other)
+  {
+  }
+
+  ValueIterator::ValueIterator (const ValueIterator &other)
+    : ValueIteratorBase (other)
+  {
+  }
+
+  ValueIterator &
+  ValueIterator::operator = (const SelfType &other)
+  {
+    copy (other);
+    return *this;
+  }
+}
+
+namespace json
+{
+  inline bool 
+  in (char c, char c1, char c2, char c3, char c4)
+  {
+    return c == c1 || c == c2 || c == c3 || c == c4;
+  }
+
+  inline bool 
+  in (char c, char c1, char c2, char c3, char c4, char c5)
+  {
+    return c == c1 || c == c2 || c == c3 || c == c4 || c == c5;
+  }
+
+
+  Reader::Reader ()
+  {
+  }
+
+  bool
+  Reader::parse (const std::string &document, 
+		 Value &root)
+  {
+    document_ = document;
+    char const *begin = document_.c_str ();
+    char const *end = begin + document_.length ();
+    return parse (begin, end, root);
+  }
+
+  bool
+  Reader::parse (std::istream& sin,
+		 Value &root)
+  {
+    std::string doc;
+    std::getline (sin, doc, (char)EOF);
+    return parse (doc, root);
+  }
+
+  bool 
+  Reader::parse (char const *beginDoc, char const *endDOc, 
+		 Value &root)
+  {
+    begin_ = beginDoc;
+    end_ = endDOc;
+    current_ = begin_;
+    lastValueEnd_ = 0;
+    lastValue_ = 0;
+    errors_.clear ();
+    while (!nodes_.empty ())
+      nodes_.pop ();
+    nodes_.push (&root);
+   
+    bool successful = readValue ();
+    return successful;
+  }
+
+
+  bool
+  Reader::readValue ()
+  {
+    Token token;
+    do
+      readToken (token);
+    while (token.type_ == tokenComment);
+    bool successful = true;
+
+    switch (token.type_)
+      {
+      case tokenObjectBegin:
+	successful = readObject ();
+	break;
+      case tokenArrayBegin:
+	successful = readArray ();
+	break;
+      case tokenNumber:
+	successful = decodeNumber (token);
+	break;
+      case tokenString:
+	successful = decodeString (token);
+	break;
+      case tokenTrue:
+	currentValue () = true;
+	break;
+      case tokenFalse:
+	currentValue () = false;
+	break;
+      case tokenNull:
+	currentValue () = Value ();
+	break;
+      default:
+	return addError ("Syntax error: value, object or array expected.", token);
+      }
+
+    return successful;
+  }
+
+
+  bool 
+  Reader::expectToken (TokenType type, Token &token, char const *message)
+  {
+    readToken (token);
+    if (token.type_ != type)
+      return addError (message, token);
+    return true;
+  }
+
+
+  bool 
+  Reader::readToken (Token &token)
+  {
+    skipSpaces ();
+    token.start_ = current_;
+    char c = getNextChar ();
+    bool ok = true;
+    switch (c)
+      {
+      case '{':
+	token.type_ = tokenObjectBegin;
+	break;
+      case '}':
+	token.type_ = tokenObjectEnd;
+	break;
+      case '[':
+	token.type_ = tokenArrayBegin;
+	break;
+      case ']':
+	token.type_ = tokenArrayEnd;
+	break;
+      case '"':
+	token.type_ = tokenString;
+	ok = readString ();
+	break;
+#if 0
+#ifdef __GNUC__
+      case '0'...'9':
+#endif
+#else
+      case '0': case '1': case '2': case '3':
+      case '4': case '5': case '6': case '7':
+      case '8': case '9':
+#endif
+      case '-':
+	token.type_ = tokenNumber;
+	readNumber ();
+	break;
+      case 't':
+	token.type_ = tokenTrue;
+	ok = match ("rue", 3);
+	break;
+      case 'f':
+	token.type_ = tokenFalse;
+	ok = match ("alse", 4);
+	break;
+      case 'n':
+	token.type_ = tokenNull;
+	ok = match ("ull", 3);
+	break;
+      case ',':
+	token.type_ = tokenArraySeparator;
+	break;
+      case ':':
+	token.type_ = tokenMemberSeparator;
+	break;
+      case 0:
+	token.type_ = tokenEndOfStream;
+	break;
+      default:
+	ok = false;
+	break;
+      }
+    if (!ok)
+      token.type_ = tokenError;
+    token.end_ = current_;
+    return true;
+  }
+
+
+  void 
+  Reader::skipSpaces ()
+  {
+    while (current_ != end_)
+      {
+	char c = *current_;
+	if (c == ' ' || c == '\t' || c == '\r' || c == '\n')
+	  ++current_;
+	else
+	  break;
+      }
+  }
+
+
+  bool 
+  Reader::match (Location pattern, int patternLength)
+  {
+    if (end_ - current_ < patternLength)
+      return false;
+    int index = patternLength;
+    while (index--)
+      if (current_[index] != pattern[index])
+	return false;
+    current_ += patternLength;
+    return true;
+  }
+
+
+  void 
+  Reader::readNumber ()
+  {
+    while (current_ != end_)
+      {
+	if (!(*current_ >= '0' && *current_ <= '9')  &&
+	     !in (*current_, '.', 'e', 'E', '+', '-'))
+	  break;
+	++current_;
+      }
+  }
+
+  bool
+  Reader::readString ()
+  {
+    char c = 0;
+    while (current_ != end_)
+      {
+	c = getNextChar ();
+	if (c == '\\')
+	  getNextChar ();
+	else if (c == '"')
+	  break;
+      }
+    return c == '"';
+  }
+
+
+  bool 
+  Reader::readObject ()
+  {
+    Token tokenName;
+    std::string name;
+    currentValue () = Value (objectValue);
+    while (readToken (tokenName))
+      {
+	if (tokenName.type_ == tokenObjectEnd && name.empty ())  // empty object
+	  return true;
+	if (tokenName.type_ != tokenString)
+	  break;
+      
+	name = "";
+	if (!decodeString (tokenName, name))
+	  return recoverFromError (tokenObjectEnd);
+
+	Token colon;
+	if (!readToken (colon) ||  colon.type_ != tokenMemberSeparator)
+	  {
+	    return addErrorAndRecover ("Missing ':' after object member name", 
+				       colon, 
+				       tokenObjectEnd);
+	  }
+	Value &value = currentValue ()[ name ];
+	nodes_.push (&value);
+	bool ok = readValue ();
+	nodes_.pop ();
+	if (!ok) // error already set
+	  return recoverFromError (tokenObjectEnd);
+
+	Token comma;
+	if (!readToken (comma)
+	     ||   (comma.type_ != tokenObjectEnd && 
+		   comma.type_ != tokenArraySeparator))
+	  {
+	    return addErrorAndRecover ("Missing ',' or '}' in object declaration", 
+				       comma, 
+				       tokenObjectEnd);
+	  }
+	if (comma.type_ == tokenObjectEnd)
+	  return true;
+      }
+    return addErrorAndRecover ("Missing '}' or object member name", 
+			       tokenName, 
+			       tokenObjectEnd);
+  }
+
+
+  bool 
+  Reader::readArray ()
+  {
+    currentValue () = Value (arrayValue);
+    skipSpaces ();
+    if (*current_ == ']') // empty array
+      {
+	Token endArray;
+	readToken (endArray);
+	return true;
+      }
+    int index = 0;
+    while (true)
+      {
+	Value &value = currentValue ()[ index++ ];
+	nodes_.push (&value);
+	bool ok = readValue ();
+	nodes_.pop ();
+	if (!ok) // error already set
+	  return recoverFromError (tokenArrayEnd);
+
+	Token token;
+	if (!readToken (token) 
+	     ||   (token.type_ != tokenArraySeparator && 
+		   token.type_ != tokenArrayEnd))
+	  {
+	    return addErrorAndRecover ("Missing ',' or ']' in array declaration", 
+				       token, 
+				       tokenArrayEnd);
+	  }
+	if (token.type_ == tokenArrayEnd)
+	  break;
+      }
+    return true;
+  }
+
+
+  bool 
+  Reader::decodeNumber (Token &token)
+  {
+    bool isDouble = false;
+    for (Location inspect = token.start_; inspect != token.end_; ++inspect)
+      {
+	isDouble = isDouble  
+	  ||  in (*inspect, '.', 'e', 'E', '+')  
+	  ||   (*inspect == '-' && inspect != token.start_);
+      }
+    if (isDouble)
+      return decodeDouble (token);
+    Location current = token.start_;
+    bool isNegative = *current == '-';
+    if (isNegative)
+      ++current;
+    unsigned threshold = (isNegative ? unsigned (-Value::minInt) 
+			     : Value::maxUInt) / 10;
+    unsigned value = 0;
+    while (current < token.end_)
+      {
+	char c = *current++;
+	if (c < '0'  ||  c > '9')
+	  return addError ("'" + std::string (token.start_, token.end_) + "' is not a number.", token);
+	if (value >= threshold)
+	  return decodeDouble (token);
+	value = value * 10 + unsigned (c - '0');
+      }
+    if (isNegative)
+      currentValue () = -int (value);
+    else if (value <= unsigned (Value::maxInt))
+      currentValue () = int (value);
+    else
+      currentValue () = value;
+    return true;
+  }
+
+
+  bool 
+  Reader::decodeDouble (Token &token)
+  {
+    double value = 0;
+    const int bufferSize = 32;
+    int count;
+    int length = int (token.end_ - token.start_);
+    if (length <= bufferSize)
+      {
+	char buffer[bufferSize];
+	memcpy (buffer, token.start_, length);
+	buffer[length] = 0;
+	count = sscanf (buffer, "%lf", &value);
+      }
+    else
+      {
+	std::string buffer (token.start_, token.end_);
+	count = sscanf (buffer.c_str (), "%lf", &value);
+      }
+
+    if (count != 1)
+      return addError ("'" + std::string (token.start_, token.end_) + "' is not a number.", token);
+    currentValue () = value;
+    return true;
+  }
+
+
+  bool 
+  Reader::decodeString (Token &token)
+  {
+    std::string decoded;
+    if (!decodeString (token, decoded))
+      return false;
+    currentValue () = decoded;
+    return true;
+  }
+
+
+  bool 
+  Reader::decodeString (Token &token, std::string &decoded)
+  {
+    Location current = token.start_ + 1; // skip '"'
+    Location end = token.end_ - 1;       // do not include '"'
+    decoded.reserve (long (end - current));
+
+    while (current != end)
+      {
+	char c = *current++;
+	if (expect_false (c == '"'))
+	  break;
+	else if (expect_false (c == '\\'))
+	  {
+	    if (expect_false (current == end))
+	      return addError ("Empty escape sequence in string", token, current);
+	    char escape = *current++;
+	    switch (escape)
+	      {
+	      case '"':
+	      case '/':
+	      case '\\': decoded += escape; break;
+
+	      case 'b': decoded += '\010'; break;
+	      case 't': decoded += '\011'; break;
+	      case 'n': decoded += '\012'; break;
+	      case 'f': decoded += '\014'; break;
+	      case 'r': decoded += '\015'; break;
+	      case 'u':
+		{
+		  unsigned unicode;
+		  if (!decodeUnicodeEscapeSequence (token, current, end, unicode))
+		    return false;
+		  // @todo encode unicode as utf8.
+		  // @todo remember to alter the writer too.
+		}
+		break;
+	      default:
+		return addError ("Bad escape sequence in string", token, current);
+	      }
+	  }
+	else
+	  {
+	    decoded += c;
+	  }
+      }
+
+    return true;
+  }
+
+
+  bool 
+  Reader::decodeUnicodeEscapeSequence (Token &token, 
+				       Location &current, 
+				       Location end, 
+				       unsigned &unicode)
+  {
+    if (end - current < 4)
+      return addError ("Bad unicode escape sequence in string: four digits expected.", token, current);
+    unicode = 0;
+    for (int index = 0; index < 4; ++index)
+      {
+	char c = *current++;
+	unicode *= 16;
+	if (c >= '0' && c <= '9')
+	  unicode += c - '0';
+	else if (c >= 'a' && c <= 'f')
+	  unicode += c - 'a' + 10;
+	else if (c >= 'A' && c <= 'F')
+	  unicode += c - 'A' + 10;
+	else
+	  return addError ("Bad unicode escape sequence in string: hexadecimal digit expected.", token, current);
+      }
+    return true;
+  }
+
+
+  bool 
+  Reader::addError (const std::string &message, 
+		    Token &token,
+		    Location extra)
+  {
+    ErrorInfo info;
+    info.token_ = token;
+    info.message_ = message;
+    info.extra_ = extra;
+    errors_.push_back (info);
+    return false;
+  }
+
+
+  bool 
+  Reader::recoverFromError (TokenType skipUntilToken)
+  {
+    int errorCount = int (errors_.size ());
+    Token skip;
+    while (true)
+      {
+	if (!readToken (skip))
+	  errors_.resize (errorCount); // discard errors caused by recovery
+	if (skip.type_ == skipUntilToken  ||  skip.type_ == tokenEndOfStream)
+	  break;
+      }
+    errors_.resize (errorCount);
+    return false;
+  }
+
+
+  bool 
+  Reader::addErrorAndRecover (const std::string &message, 
+			      Token &token,
+			      TokenType skipUntilToken)
+  {
+    addError (message, token);
+    return recoverFromError (skipUntilToken);
+  }
+
+
+  Value &
+  Reader::currentValue ()
+  {
+    return *(nodes_.top ());
+  }
+
+
+  char 
+  Reader::getNextChar ()
+  {
+    if (current_ == end_)
+      return 0;
+    return *current_++;
+  }
+
+
+  void 
+  Reader::getLocationLineAndColumn (Location location,
+				    int &line,
+				    int &column) const
+  {
+    Location current = begin_;
+    Location lastLineStart = current;
+    line = 0;
+    while (current < location && current != end_)
+      {
+	char c = *current++;
+	if (c == '\r')
+	  {
+	    if (*current == '\n')
+	      ++current;
+	    lastLineStart = current;
+	    ++line;
+	  }
+	else if (c == '\n')
+	  {
+	    lastLineStart = current;
+	    ++line;
+	  }
+      }
+    // column & line start at 1
+    column = int (location - lastLineStart) + 1;
+    ++line;
+  }
+
+
+  std::string
+  Reader::getLocationLineAndColumn (Location location) const
+  {
+    int line, column;
+    getLocationLineAndColumn (location, line, column);
+    char buffer[18+16+16+1];
+    sprintf (buffer, "Line %d, Column %d", line, column);
+    return buffer;
+  }
+
+
+  std::string 
+  Reader::error_msgs () const
+  {
+    std::string formattedMessage;
+    for (Errors::const_iterator itError = errors_.begin ();
+	  itError != errors_.end ();
+	  ++itError)
+      {
+	const ErrorInfo &error = *itError;
+	formattedMessage += "* " + getLocationLineAndColumn (error.token_.start_) + "\n";
+	formattedMessage += "  " + error.message_ + "\n";
+	if (error.extra_)
+	  formattedMessage += "See " + getLocationLineAndColumn (error.extra_) + " for detail.\n";
+      }
+    return formattedMessage;
+  }
+} // namespace json
+
+namespace json
+{
+  void
+  unreachable_internal (char const *file, int line, char const *function)
+  {
+    char buf[1024];
+    snprintf (buf, 1024, "%s (%d) [%s] critical: Unreachable line reached.",
+	      file, line, function);
+  
+    throw std::runtime_error (buf);
+  }
+  
+  void
+  throw_unless_internal (char const *file, int line, char const *function, char const *condition)
+  {
+    char buf[1024];
+    snprintf (buf, 1024, "%s (%d) [%s] critical: Assertion `%s' failed.",
+	      file, line, function, condition);
+  
+    throw std::runtime_error (buf);
+  }
+  
+  void
+  throw_msg_unless_internal (char const *file, int line, char const *function, char const *message)
+  {
+    char buf[1024];
+    snprintf (buf, 1024, "%s (%d) [%s] critical: %s.",
+	      file, line, function, message);
+  
+    throw std::runtime_error (buf);
+  }
+  
+  const Value Value::null;
+  const int Value::minInt = int (~ (unsigned (-1)/2));
+  const int Value::maxInt = int (unsigned (-1)/2);
+  const unsigned Value::maxUInt = unsigned (-1);
+
+  ValueAllocator::~ValueAllocator ()
+  {
+  }
+
+  class DefaultValueAllocator : public ValueAllocator
+  {
+  public:
+    virtual ~DefaultValueAllocator ()
+    {
+    }
+
+    virtual char *makeMemberName (char const *memberName)
+    {
+      return duplicateStringValue (memberName);
+    }
+
+    virtual void releaseMemberName (char *memberName)
+    {
+      releaseStringValue (memberName);
+    }
+
+    virtual char *duplicateStringValue (char const *value, unsigned length = unknown)
+    {
+      //@todo invesgate this old optimization
+#if 0
+      if (!value || value[0] == 0)
+	return 0;
+#endif
+
+      if (length == unknown)
+	length = (unsigned)strlen (value);
+      char *newString = static_cast<char *> (malloc (length + 1));
+      memcpy (newString, value, length);
+      newString[length] = 0;
+      return newString;
+    }
+
+    virtual void releaseStringValue (char *value)
+    {
+      if (value)
+	free (value);
+    }
+  };
+
+  static ValueAllocator *&valueAllocator ()
+  {
+    static DefaultValueAllocator defaultAllocator;
+    static ValueAllocator *valueAllocator = &defaultAllocator;
+    return valueAllocator;
+  }
+
+  static struct DummyValueAllocatorInitializer {
+    DummyValueAllocatorInitializer () 
+    {
+      valueAllocator ();      // ensure valueAllocator () statics are initialized before main ().
+    }
+  } dummyValueAllocatorInitializer;
+
+
+
+  Value::CZString::CZString (int index)
+    : cstr_ (0)
+    , index_ (index)
+  {
+  }
+
+  Value::CZString::CZString (char const *cstr, DuplicationPolicy allocate)
+    : cstr_ (allocate == duplicate ? valueAllocator()->makeMemberName (cstr) 
+	     : cstr)
+    , index_ (allocate)
+  {
+  }
+
+  Value::CZString::CZString (const CZString &other)
+    : cstr_ (other.index_ != noDuplication &&  other.cstr_ != 0
+	     ?  valueAllocator()->makeMemberName (other.cstr_)
+	     : other.cstr_)
+    , index_ (other.cstr_ ? (other.index_ == noDuplication ? noDuplication : duplicate)
+	      : other.index_)
+  {
+  }
+
+  Value::CZString::~CZString ()
+  {
+    if (cstr_ && index_ == duplicate)
+      valueAllocator()->releaseMemberName (const_cast<char *> (cstr_));
+  }
+
+  void 
+  Value::CZString::swap (CZString &other)
+  {
+    std::swap (cstr_, other.cstr_);
+    std::swap (index_, other.index_);
+  }
+
+  Value::CZString &
+  Value::CZString::operator = (const CZString &other)
+  {
+    CZString temp (other);
+    swap (temp);
+    return *this;
+  }
+
+  bool 
+  Value::CZString::operator < (const CZString &other) const 
+  {
+    if (cstr_)
+      return strcmp (cstr_, other.cstr_) < 0;
+    return index_ < other.index_;
+  }
+
+  bool 
+  Value::CZString::operator == (const CZString &other) const 
+  {
+    if (cstr_)
+      return strcmp (cstr_, other.cstr_) == 0;
+    return index_ == other.index_;
+  }
+
+
+  int 
+  Value::CZString::index () const
+  {
+    return index_;
+  }
+
+
+  char const *
+  Value::CZString::c_str () const
+  {
+    return cstr_;
+  }
+
+  bool 
+  Value::CZString::isStaticString () const
+  {
+    return index_ == noDuplication;
+  }
+
+
+  // class Value::Value
+
+  Value::Value (ValueType type)
+    : type_ (type)
+    , allocated_ (0)
+  {
+    switch (type)
+      {
+      case nullValue:
+	break;
+      case intValue:
+      case uintValue:
+	value_.int_ = 0;
+	break;
+      case realValue:
+	value_.real_ = 0.0;
+	break;
+      case stringValue:
+	value_.string_ = 0;
+	break;
+      case arrayValue:
+      case objectValue:
+	value_.map_ = new ObjectValues ();
+	break;
+      case booleanValue:
+	value_.bool_ = false;
+	break;
+      default:
+	throw_unreachable;
+      }
+  }
+
+
+  Value::Value (int value)
+    : type_ (intValue)
+  {
+    value_.int_ = value;
+  }
+
+
+  Value::Value (unsigned value)
+    : type_ (uintValue)
+  {
+    value_.uint_ = value;
+  }
+
+  Value::Value (double value)
+    : type_ (realValue)
+  {
+    value_.real_ = value;
+  }
+
+  Value::Value (char const *value)
+    : type_ (stringValue)
+    , allocated_ (true)
+  {
+    value_.string_ = valueAllocator()->duplicateStringValue (value);
+  }
+
+  Value::Value (const std::string &value)
+    : type_ (stringValue)
+    , allocated_ (true)
+  {
+    value_.string_ = valueAllocator()->duplicateStringValue (value.c_str (), (unsigned)value.length ());
+  }
+
+  Value::Value (const StaticString &value)
+    : type_ (stringValue)
+    , allocated_ (false)
+  {
+    value_.string_ = const_cast<char *> (value.c_str ());
+  }
+
+
+  Value::Value (bool value)
+    : type_ (booleanValue)
+  {
+    value_.bool_ = value;
+  }
+
+
+  Value::Value (const Value &other)
+    : type_ (other.type_)
+  {
+    switch (type_)
+      {
+      case nullValue:
+      case intValue:
+      case uintValue:
+      case realValue:
+      case booleanValue:
+	value_ = other.value_;
+	break;
+      case stringValue:
+	if (other.value_.string_)
+	  {
+	    value_.string_ = valueAllocator()->duplicateStringValue (other.value_.string_);
+	    allocated_ = true;
+	  }
+	else
+	  value_.string_ = 0;
+	break;
+      case arrayValue:
+      case objectValue:
+	value_.map_ = new ObjectValues (*other.value_.map_);
+	break;
+      default:
+	throw_unreachable;
+      }
+  }
+
+
+  Value::~Value ()
+  {
+    switch (type_)
+      {
+      case nullValue:
+      case intValue:
+      case uintValue:
+      case realValue:
+      case booleanValue:
+	break;
+      case stringValue:
+	if (allocated_)
+	  valueAllocator()->releaseStringValue (value_.string_);
+	break;
+      case arrayValue:
+      case objectValue:
+	delete value_.map_;
+	break;
+      default:
+	throw_unreachable;
+      }
+  }
+
+  Value &
+  Value::operator = (const Value &other)
+  {
+    Value temp (other);
+    swap (temp);
+    return *this;
+  }
+
+  void 
+  Value::swap (Value &other)
+  {
+    ValueType temp = type_;
+    type_ = other.type_;
+    other.type_ = temp;
+    std::swap (value_, other.value_);
+    int temp2 = allocated_;
+    allocated_ = other.allocated_;
+    other.allocated_ = temp2;
+  }
+
+  ValueType 
+  Value::type () const
+  {
+    return type_;
+  }
+
+  bool 
+  Value::operator < (const Value &other) const
+  {
+    int typeDelta = type_ - other.type_;
+    if (typeDelta)
+      return typeDelta < 0 ? true : false;
+    switch (type_)
+      {
+      case nullValue:
+	return false;
+      case intValue:
+	return value_.int_ < other.value_.int_;
+      case uintValue:
+	return value_.uint_ < other.value_.uint_;
+      case realValue:
+	return value_.real_ < other.value_.real_;
+      case booleanValue:
+	return value_.bool_ < other.value_.bool_;
+      case stringValue:
+	return (value_.string_ == 0 && other.value_.string_)
+	  || (other.value_.string_  
+	      && value_.string_  
+	      && strcmp (value_.string_, other.value_.string_) < 0);
+      case arrayValue:
+      case objectValue:
+	{
+	  int delta = int (value_.map_->size () - other.value_.map_->size ());
+	  if (delta)
+	    return delta < 0;
+	  return (*value_.map_) < (*other.value_.map_);
+	}
+      default:
+	throw_unreachable;
+      }
+    return 0;  // unreachable
+  }
+
+  bool 
+  Value::operator <= (const Value &other) const
+  {
+    return !(other > *this);
+  }
+
+  bool 
+  Value::operator >= (const Value &other) const
+  {
+    return !(*this < other);
+  }
+
+  bool 
+  Value::operator > (const Value &other) const
+  {
+    return other < *this;
+  }
+
+  bool 
+  Value::operator == (const Value &other) const
+  {
+    if (type_ != other.type_)
+      return false;
+
+    switch (type_)
+      {
+      case nullValue:
+	return true;
+      case intValue:
+	return value_.int_ == other.value_.int_;
+      case uintValue:
+	return value_.uint_ == other.value_.uint_;
+      case realValue:
+	return value_.real_ == other.value_.real_;
+      case booleanValue:
+	return value_.bool_ == other.value_.bool_;
+      case stringValue:
+	return (value_.string_ == other.value_.string_)
+	  || (other.value_.string_  
+	      && value_.string_  
+	      && strcmp (value_.string_, other.value_.string_) == 0);
+      case arrayValue:
+      case objectValue:
+	return value_.map_->size () == other.value_.map_->size ()
+	  && (*value_.map_) == (*other.value_.map_);
+      default:
+	throw_unreachable;
+      }
+    return 0;  // unreachable
+  }
+
+  bool 
+  Value::operator != (const Value &other) const
+  {
+    return !(*this == other);
+  }
+
+  Value::operator char const * () const
+  {
+    throw_unless (type_ == stringValue);
+    return value_.string_;
+  }
+
+
+  Value::operator std::string () const
+  {
+    switch (type_)
+      {
+      case nullValue:
+	return "";
+      case stringValue:
+	return value_.string_ ? value_.string_ : "";
+      case booleanValue:
+	return value_.bool_ ? "true" : "false";
+      case intValue:
+      case uintValue:
+      case realValue:
+      case arrayValue:
+      case objectValue:
+	throw_msg_unless (false, "Type is not convertible to string");
+      default:
+	throw_unreachable;
+      }
+    return ""; // unreachable
+  }
+
+  Value::operator int () const
+  {
+    switch (type_)
+      {
+      case nullValue:
+	return 0;
+      case intValue:
+	return value_.int_;
+      case uintValue:
+	throw_msg_unless (value_.uint_ < (unsigned)maxInt, "integer out of signed integer range");
+	return value_.uint_;
+      case realValue:
+	throw_msg_unless (value_.real_ >= minInt && value_.real_ <= maxInt, "Real out of signed integer range");
+	return int (value_.real_);
+      case booleanValue:
+	return value_.bool_ ? 1 : 0;
+      case stringValue:
+      case arrayValue:
+      case objectValue:
+	throw_msg_unless (false, "Type is not convertible to int");
+      default:
+	throw_unreachable;
+      }
+    return 0; // unreachable;
+  }
+
+  Value::operator unsigned () const
+  {
+    switch (type_)
+      {
+      case nullValue:
+	return 0;
+      case intValue:
+	throw_msg_unless (value_.int_ >= 0, "Negative integer can not be converted to unsigned integer");
+	return value_.int_;
+      case uintValue:
+	return value_.uint_;
+      case realValue:
+	throw_msg_unless (value_.real_ >= 0 && value_.real_ <= maxUInt,  "Real out of unsigned integer range");
+	return unsigned (value_.real_);
+      case booleanValue:
+	return value_.bool_ ? 1 : 0;
+      case stringValue:
+      case arrayValue:
+      case objectValue:
+	throw_msg_unless (false, "Type is not convertible to uint");
+      default:
+	throw_unreachable;
+      }
+    return 0; // unreachable;
+  }
+
+  Value::operator double () const
+  {
+    switch (type_)
+      {
+      case nullValue:
+	return 0.0;
+      case intValue:
+	return value_.int_;
+      case uintValue:
+	return value_.uint_;
+      case realValue:
+	return value_.real_;
+      case booleanValue:
+	return value_.bool_ ? 1.0 : 0.0;
+      case stringValue:
+      case arrayValue:
+      case objectValue:
+	throw_msg_unless (false, "Type is not convertible to double");
+      default:
+	throw_unreachable;
+      }
+    return 0; // unreachable;
+  }
+
+  Value::operator bool () const
+  {
+    switch (type_)
+      {
+      case nullValue:
+	return false;
+      case intValue:
+      case uintValue:
+	return value_.int_ != 0;
+      case realValue:
+	return value_.real_ != 0.0;
+      case booleanValue:
+	return value_.bool_;
+      case stringValue:
+	return value_.string_ && value_.string_[0] != 0;
+      case arrayValue:
+      case objectValue:
+	return value_.map_->size () != 0;
+      default:
+	throw_unreachable;
+      }
+    return false; // unreachable;
+  }
+
+
+  bool 
+  Value::isConvertibleTo (ValueType other) const
+  {
+    switch (type_)
+      {
+      case nullValue:
+	return true;
+      case intValue:
+	return (other == nullValue && value_.int_ == 0)
+	  || other == intValue
+	  || (other == uintValue  && value_.int_ >= 0)
+	  || other == realValue
+	  || other == stringValue
+	  || other == booleanValue;
+      case uintValue:
+	return (other == nullValue && value_.uint_ == 0)
+	  || (other == intValue  && value_.uint_ <= (unsigned)maxInt)
+	  || other == uintValue
+	  || other == realValue
+	  || other == stringValue
+	  || other == booleanValue;
+      case realValue:
+	return (other == nullValue && value_.real_ == 0.0)
+	  || (other == intValue && value_.real_ >= minInt && value_.real_ <= maxInt)
+	  || (other == uintValue && value_.real_ >= 0 && value_.real_ <= maxUInt)
+	  || other == realValue
+	  || other == stringValue
+	  || other == booleanValue;
+      case booleanValue:
+	return (other == nullValue && value_.bool_ == false)
+	  || other == intValue
+	  || other == uintValue
+	  || other == realValue
+	  || other == stringValue
+	  || other == booleanValue;
+      case stringValue:
+	return other == stringValue
+	  || (other == nullValue && (!value_.string_ || value_.string_[0] == 0));
+      case arrayValue:
+	return other == arrayValue
+	  || (other == nullValue && value_.map_->size () == 0);
+      case objectValue:
+	return other == objectValue
+	  || (other == nullValue && value_.map_->size () == 0);
+      default:
+	throw_unreachable;
+      }
+    return false; // unreachable;
+  }
+
+
+  /// Number of values in array or object
+  unsigned 
+  Value::size () const
+  {
+    switch (type_)
+      {
+      case nullValue:
+      case intValue:
+      case uintValue:
+      case realValue:
+      case booleanValue:
+      case stringValue:
+	return 0;
+      case arrayValue:  // size of the array is highest index + 1
+	if (!value_.map_->empty ())
+	  {
+	    ObjectValues::const_iterator itLast = value_.map_->end ();
+	    --itLast;
+	    return itLast->first.index ()+1;
+	  }
+	return 0;
+      case objectValue:
+	return int (value_.map_->size ());
+      default:
+	throw_unreachable;
+      }
+    return 0; // unreachable;
+  }
+
+
+  bool 
+  Value::empty () const
+  {
+    if (isNull () || isArray () || isObject ())
+      return size () == 0u;
+    else
+      return false;
+  }
+
+
+  bool
+  Value::operator ! () const
+  {
+    return isNull ();
+  }
+
+
+  void 
+  Value::clear ()
+  {
+    throw_unless (type_ == nullValue || type_ == arrayValue  || type_ == objectValue);
+
+    switch (type_)
+      {
+      case arrayValue:
+      case objectValue:
+	value_.map_->clear ();
+	break;
+      default:
+	break;
+      }
+  }
+
+  void 
+  Value::resize (unsigned newSize)
+  {
+    throw_unless (type_ == nullValue || type_ == arrayValue);
+    if (type_ == nullValue)
+      *this = Value (arrayValue);
+    unsigned oldSize = size ();
+    if (newSize == 0)
+      clear ();
+    else if (newSize > oldSize)
+      (*this)[ newSize - 1 ];
+    else
+      {
+	for (unsigned index = newSize; index < oldSize; ++index)
+	  value_.map_->erase (index);
+	throw_unless (size () == newSize);
+      }
+  }
+
+
+  Value &
+  Value::operator [] (int index)
+  {
+    return operator [] (static_cast<unsigned> (index));
+  }
+
+
+  Value &
+  Value::operator [] (unsigned index)
+  {
+    throw_unless (type_ == nullValue || type_ == arrayValue);
+    if (type_ == nullValue)
+      *this = Value (arrayValue);
+    CZString key (index);
+    ObjectValues::iterator it = value_.map_->lower_bound (key);
+    if (it != value_.map_->end () && it->first == key)
+      return it->second;
+
+    ObjectValues::value_type defaultValue (key, null);
+    it = value_.map_->insert (it, defaultValue);
+    return it->second;
+  }
+
+
+  const Value &
+  Value::operator [] (int index) const
+  {
+    return operator [] (static_cast<unsigned> (index));
+  }
+
+
+  const Value &
+  Value::operator [] (unsigned index) const
+  {
+    throw_unless (type_ == nullValue || type_ == arrayValue);
+    if (type_ == nullValue)
+      return null;
+    CZString key (index);
+    ObjectValues::const_iterator it = value_.map_->find (key);
+    if (it == value_.map_->end ())
+      return null;
+    return it->second;
+  }
+
+
+  Value &
+  Value::operator [] (char const *key)
+  {
+    return resolveReference (key, false);
+  }
+
+
+  Value &
+  Value::resolveReference (char const *key, bool isStatic)
+  {
+    throw_unless (type_ == nullValue || type_ == objectValue);
+    if (type_ == nullValue)
+      *this = Value (objectValue);
+    CZString actualKey (key, isStatic ? CZString::noDuplication 
+			: CZString::duplicateOnCopy);
+    ObjectValues::iterator it = value_.map_->lower_bound (actualKey);
+    if (it != value_.map_->end () && it->first == actualKey)
+      return it->second;
+
+    ObjectValues::value_type defaultValue (actualKey, null);
+    it = value_.map_->insert (it, defaultValue);
+    Value &value = it->second;
+    return value;
+  }
+
+
+  Value 
+  Value::get (int index, const Value &defaultValue) const
+  {
+    return get (static_cast<unsigned> (index), defaultValue);
+  }
+
+
+  Value 
+  Value::get (unsigned index, const Value &defaultValue) const
+  {
+    const Value *value = &((*this)[index]);
+    return value == &null ? defaultValue : *value;
+  }
+
+
+  bool 
+  Value::isValidIndex (int index) const
+  {
+    return isValidIndex (static_cast<unsigned> (index));
+  }
+
+
+  bool 
+  Value::isValidIndex (unsigned index) const
+  {
+    return index < size ();
+  }
+
+
+
+  const Value &
+  Value::operator [] (char const *key) const
+  {
+    throw_unless (type_ == nullValue || type_ == objectValue);
+    if (type_ == nullValue)
+      return null;
+    CZString actualKey (key, CZString::noDuplication);
+    ObjectValues::const_iterator it = value_.map_->find (actualKey);
+    if (it == value_.map_->end ())
+      return null;
+    return it->second;
+  }
+
+
+  Value &
+  Value::operator [] (const std::string &key)
+  {
+    return (*this)[ key.c_str () ];
+  }
+
+
+  const Value &
+  Value::operator [] (const std::string &key) const
+  {
+    return (*this)[ key.c_str () ];
+  }
+
+  Value &
+  Value::operator [] (const StaticString &key)
+  {
+    return resolveReference (key, true);
+  }
+
+
+  Value &
+  Value::append (const Value &value)
+  {
+    return (*this)[size ()] = value;
+  }
+
+
+  Value 
+  Value::get (char const *key, const Value &defaultValue) const
+  {
+    const Value *value = &((*this)[key]);
+    return value == &null ? defaultValue : *value;
+  }
+
+
+  Value 
+  Value::get (const std::string &key, const Value &defaultValue) const
+  {
+    return get (key.c_str (), defaultValue);
+  }
+
+  Value
+  Value::removeMember (char const *key)
+  {
+    throw_unless (type_ == nullValue || type_ == objectValue);
+    if (type_ == nullValue)
+      return null;
+    CZString actualKey (key, CZString::noDuplication);
+    ObjectValues::iterator it = value_.map_->find (actualKey);
+    if (it == value_.map_->end ())
+      return null;
+    Value old (it->second);
+    value_.map_->erase (it);
+    return old;
+  }
+
+  Value
+  Value::removeMember (const std::string &key)
+  {
+    return removeMember (key.c_str ());
+  }
+
+  bool 
+  Value::isMember (char const *key) const
+  {
+    const Value *value = &((*this)[key]);
+    return value != &null;
+  }
+
+
+  bool 
+  Value::isMember (const std::string &key) const
+  {
+    return isMember (key.c_str ());
+  }
+
+
+  Value::Members 
+  Value::getMemberNames () const
+  {
+    throw_unless (type_ == nullValue || type_ == objectValue);
+    if (type_ == nullValue)
+      return Value::Members ();
+    Members members;
+    members.reserve (value_.map_->size ());
+    ObjectValues::const_iterator it;
+    ObjectValues::const_iterator itEnd = value_.map_->end ();
+    for (it = value_.map_->begin (); it != itEnd; ++it)
+      members.push_back (std::string (it->first.c_str()));
+    return members;
+  }
+
+  bool
+  Value::isNull () const
+  {
+    return type_ == nullValue;
+  }
+
+
+  bool 
+  Value::isBool () const
+  {
+    return type_ == booleanValue;
+  }
+
+
+  bool 
+  Value::isInt () const
+  {
+    return type_ == intValue;
+  }
+
+
+  bool 
+  Value::isUInt () const
+  {
+    return type_ == uintValue;
+  }
+
+
+  bool 
+  Value::isIntegral () const
+  {
+    return type_ == intValue  
+      || type_ == uintValue  
+      || type_ == booleanValue;
+  }
+
+
+  bool 
+  Value::isDouble () const
+  {
+    return type_ == realValue;
+  }
+
+
+  bool 
+  Value::isNumeric () const
+  {
+    return isIntegral () || isDouble ();
+  }
+
+
+  bool 
+  Value::isString () const
+  {
+    return type_ == stringValue;
+  }
+
+
+  bool 
+  Value::isArray () const
+  {
+    return type_ == nullValue || type_ == arrayValue;
+  }
+
+
+  bool 
+  Value::isObject () const
+  {
+    return type_ == nullValue || type_ == objectValue;
+  }
+
+
+  Value::const_iterator 
+  Value::begin () const
+  {
+    switch (type_)
+      {
+      case arrayValue:
+      case objectValue:
+	if (value_.map_)
+	  return const_iterator (value_.map_->begin ());
+	break;
+      default:
+	break;
+      }
+    return const_iterator ();
+  }
+
+  Value::const_iterator 
+  Value::end () const
+  {
+    switch (type_)
+      {
+      case arrayValue:
+      case objectValue:
+	if (value_.map_)
+	  return const_iterator (value_.map_->end ());
+	break;
+      default:
+	break;
+      }
+    return const_iterator ();
+  }
+
+
+  Value::iterator 
+  Value::begin ()
+  {
+    switch (type_)
+      {
+      case arrayValue:
+      case objectValue:
+	if (value_.map_)
+	  return iterator (value_.map_->begin ());
+	break;
+      default:
+	break;
+      }
+    return iterator ();
+  }
+
+  Value::iterator 
+  Value::end ()
+  {
+    switch (type_)
+      {
+      case arrayValue:
+      case objectValue:
+	if (value_.map_)
+	  return iterator (value_.map_->end ());
+	break;
+      default:
+	break;
+      }
+    return iterator ();
+  }
+} // namespace json
+
+namespace json
+{
+  static void uintToString (unsigned value, 
+			    char *&current)
+  {
+    *--current = 0;
+    do
+      {
+	*--current = (value % 10) + '0';
+	value /= 10;
+      }
+    while (value != 0);
+  }
+
+  std::string valueToString (int value)
+  {
+    char buffer[32];
+    char *current = buffer + sizeof (buffer);
+    bool isNegative = value < 0;
+    if (isNegative)
+      value = -value;
+    uintToString (unsigned (value), current);
+    if (isNegative)
+      *--current = '-';
+    throw_unless (current >= buffer);
+    return current;
+  }
+
+
+  std::string valueToString (unsigned value)
+  {
+    char buffer[32];
+    char *current = buffer + sizeof (buffer);
+    uintToString (value, current);
+    throw_unless (current >= buffer);
+    return current;
+  }
+
+  std::string valueToString (double value)
+  {
+    char buffer[32];
+    sprintf (buffer, "%.16g", value); 
+    return buffer;
+  }
+
+
+  std::string valueToString (bool value)
+  {
+    return value ? "true" : "false";
+  }
+
+  std::string valueToQuotedString (char const *value)
+  {
+    // Not sure how to handle unicode...
+    if (std::strpbrk (value, "\"\\\b\f\n\r\t") == NULL)
+      return std::string ("\"") + value + "\"";
+    // We have to walk value and escape any special characters.
+    // Appending to std::string is not efficient, but this should be rare.
+    // (Note: forward slashes are *not* rare, but I am not escaping them.)
+    unsigned maxsize = strlen (value) * 2 + 3; // allescaped+quotes+NULL
+    std::string result;
+    result.reserve (maxsize); // to avoid lots of mallocs
+    result += "\"";
+    for (char const* c=value; *c != 0; ++c){
+      switch (*c){
+      case '\"':
+	result += "\\\"";
+	break;
+      case '\\':
+	result += "\\\\";
+	break;
+      case '\b':
+	result += "\\b";
+	break;
+      case '\f':
+	result += "\\f";
+	break;
+      case '\n':
+	result += "\\n";
+	break;
+      case '\r':
+	result += "\\r";
+	break;
+      case '\t':
+	result += "\\t";
+	break;
+      case '/':
+	// Even though \/ is considered a legal escape in JSON, a bare
+	// slash is also legal, so I see no reason to escape it.
+	// (I hope I am not misunderstanding something.)
+      default:
+	result += *c;
+      }
+    }
+    result += "\"";
+    return result;
+  }
+
+  // Class Writer
+  std::string 
+  Writer::write (const Value &root)
+  {
+    document_ = "";
+    writeValue (root);
+    document_ += "\n";
+    return document_;
+  }
+
+
+  void 
+  Writer::writeValue (const Value &value)
+  {
+    switch (value.type ())
+      {
+      case nullValue:
+	document_ += "null";
+	break;
+      case intValue:
+	document_ += valueToString (static_cast<int> (value));
+	break;
+      case uintValue:
+	document_ += valueToString (static_cast<unsigned> (value));
+	break;
+      case realValue:
+	document_ += valueToString (static_cast<double> (value));
+	break;
+      case stringValue:
+	document_ += valueToQuotedString (static_cast<char const *> (value));
+	break;
+      case booleanValue:
+	document_ += valueToString (static_cast<bool> (value));
+	break;
+      case arrayValue:
+	{
+	  document_ += "[";
+	  int size = value.size ();
+	  for (int index = 0; index < size; ++index)
+	    {
+	      if (index > 0)
+		document_ += ",";
+	      writeValue (value[index]);
+	    }
+	  document_ += "]";
+	}
+	break;
+      case objectValue:
+	{
+	  Value::Members members (value.getMemberNames ());
+	  document_ += "{";
+	  for (Value::Members::iterator it = members.begin (); 
+		it != members.end (); 
+		++it)
+	    {
+	      const std::string &name = *it;
+	      if (it != members.begin ())
+		document_ += ",";
+	      document_ += valueToQuotedString (name.c_str ());
+	      document_ += ":";
+	      writeValue (value[name]);
+	    }
+	  document_ += "}";
+	}
+	break;
+      }
+  }
+} // namespace json
+
+/**
+ * RPC
+ */
+
+namespace json
+{
+  namespace rpc
+  {
+    typedef std::map<std::string, void (*) (HTTPRequest *, Value &, Value &)> method_map;
+  
+    method_map methods;
+  
+    void
+    add_method (char *name, method mth)
+    {
+      methods[name] = mth;
+    }
+  
+    void
+    system_list_methods (HTTPRequest *http, Value &request, Value &response)
+    {
+      unsigned i = 0;
+      Value method_list (arrayValue);
+    
+      method_map::iterator it;
+      for (it = methods.begin(); it != methods.end(); ++it)
+	{
+	  method_list[i] = Value (it->first);
+	  i++;
+	}
+    
+      response["result"] = method_list;
+    }
+
+    void
+    init ()
+    {
+      add_method ("system.listMethods", &system_list_methods);
+    }
+  
+    void
+    service (HTTPRequest *http, Value &request, Value &response)
+    {
+      char const *methodName = static_cast<char const *> (request["method"]);
+      
+      method_map::iterator mth = methods.find (methodName);
+      if (mth != methods.end ())
+	(*mth->second) (http, request, response);
+    }
+    
+    void
+    process (HTTPRequest *http, std::string &response_text, char const *request_text)
+    {
+      std::string text;
+      bool parse_success;
+      Value request (objectValue);
+      Value response (objectValue);
+      Reader r;
+      Writer w;
+  
+      parse_success = r.parse (request_text, request_text + strlen (request_text), request);
+  
+      service (http, request, response);
+  
+      text = w.write (response);
+  
+      response_text = text.c_str ();
+  
+      return;
+    }
+  } // namespace rpc
+} // namespace json
+
+MODULE_INIT(ModuleRpcJson)