/*
 * Copyright © 2007 Pippijn van Steenhoven / The Ermyth Team
 * Rights to this code are as documented in doc/pod/license.pod.
 *
 * JSON-RPC for Ermyth
 *
 * $Id: value.C,v 1.5 2007/09/22 14:27:30 pippijn Exp $
 */

//>>>>>>>>>>> value.C <<<<<<<<<<<//
#include <json/value.h>
#include <json/writer.h>

#include <iostream>
#include <utility>
#include <stdexcept>

#include <cstddef>    // size_t

#include "atheme.h"
#include <util/memory.h>
#include <util/containers.h>

namespace json
{
  namespace impl
  {
    template<typename inttype = int, typename floattype = float, inttype maxUlps = 200>
    struct equals
    {
      bool operator () (floattype A, floattype B)
      {
        inttype aInt = *(inttype*)&A;
        inttype bInt = *(inttype*)&B;
        
        // Make aInt lexicographically ordered as a twos-complement int
        if (aInt < 0)
          aInt = 0x80000000 - aInt;
        
        // Make bInt lexicographically ordered as a twos-complement int
        if (bInt < 0)
          bInt = 0x80000000 - bInt;
        
        inttype intDiff = abs(aInt - bInt);
        if (intDiff <= maxUlps)
          return true;
        
        return false;
      }
    };
  }

  void unreachable_internal (char const * const file,
                             int const line,
                             char const * const function)
                             __attribute__ ((__noreturn__));
  void
  unreachable_internal (char const * const file, int const line, char const * 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 * const file,
                              int const line,
                              char const * const function,
                              char const * const condition)
                              __attribute__ ((__noreturn__));
  void
  throw_unless_internal (char const * const file, int const line, char const * const function, char const * 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 * const file,
                                  int const line,
                                  char const * const function,
                                  char const * const message)
                                  __attribute__ ((__noreturn__));
  void
  throw_msg_unless_internal (char const * const file, int const line, char const * const function, char const * const message)
  {
    char buf[1024];
    snprintf (buf, 1024, "%s (%d) [%s] critical: %s.",
              file, line, function, message);
  
    throw std::runtime_error (buf);
  }

#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)
  
  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 = salloc<char> (length + 1);
      memcpy (newString, value, length);
      newString[length] = 0;
      return newString;
    }

    virtual void releaseStringValue (char *value)
    {
      if (value)
        sfree (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;



  // class Value::CommentInfo
  Value::CommentInfo::CommentInfo ()
    : comment_ (0)
  {
  }

  Value::CommentInfo::~CommentInfo ()
  {
    if (comment_)
      valueAllocator()->releaseStringValue (comment_);
  }


  void 
  Value::CommentInfo::setComment (char const *text)
  {
    if (comment_)
      valueAllocator()->releaseStringValue (comment_);
    throw_unless (text);
    throw_msg_unless (text[0]=='\0' || text[0]=='/', "Comments must start with /");
    // It seems that /**/ style comments are acceptable as well.
    comment_ = valueAllocator()->duplicateStringValue (text);
  }


  // class Value::CZString

  // Notes: index_ indicates if the string was allocated when
  // a string is stored.

  Value::CZString::CZString (int idx)
    : cstr_ (0)
    , index_ (idx)
  {
  }

  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

  /*! \internal Default constructor initialization must be equivalent to:
   * memset (this, 0, sizeof (Value))
   * This optimization is used in ValueInternalMap fast allocator.
   */
  Value::Value (ValueType t)
    : type_ (t)
    , allocated_ (0)
    , comments_ (0)
  {
    switch (t)
      {
      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)
    , comments_ (0)
  {
    value_.int_ = value;
  }


  Value::Value (unsigned value)
    : type_ (uintValue)
    , comments_ (0)
  {
    value_.uint_ = value;
  }

  Value::Value (double value)
    : type_ (realValue)
    , comments_ (0)
  {
    value_.real_ = value;
  }

  Value::Value (char const *value)
    : type_ (stringValue)
    , allocated_ (true)
    , comments_ (0)
  {
    value_.string_ = valueAllocator()->duplicateStringValue (value);
  }

  Value::Value (const std::string &value)
    : type_ (stringValue)
    , allocated_ (true)
    , comments_ (0)
  {
    value_.string_ = valueAllocator()->duplicateStringValue (value.c_str (), (unsigned)value.length ());
  }

  Value::Value (const StaticString &value)
    : type_ (stringValue)
    , allocated_ (false)
    , comments_ (0)
  {
    value_.string_ = const_cast<char *> (value.c_str ());
  }


  Value::Value (bool value)
    : type_ (booleanValue)
    , comments_ (0)
  {
    value_.bool_ = value;
  }


  Value::Value (const Value &other)
    : type_ (other.type_)
    , comments_ (0)
  {
    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;
      }
    if (other.comments_)
      {
        comments_ = new CommentInfo[numberOfCommentPlacement];
        for (int comment = 0; comment < numberOfCommentPlacement; ++comment)
          {
            const CommentInfo &otherComment = other.comments_[comment];
            if (otherComment.comment_)
              comments_[comment].setComment (otherComment.comment_);
          }
      }
  }


  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;
      }

    if (comments_)
      delete[] comments_;
  }

  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 impl::equals<> () (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 impl::equals<> () (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 && impl::equals<> () (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;
  }


  void 
  Value::setComment (char const *comment,
                     CommentPlacement placement)
  {
    if (!comments_)
      comments_ = new CommentInfo[numberOfCommentPlacement];
    comments_[placement].setComment (comment);
  }


  void 
  Value::setComment (const std::string &comment,
                     CommentPlacement placement)
  {
    setComment (comment.c_str (), placement);
  }


  bool 
  Value::hasComment (CommentPlacement placement) const
  {
    return comments_ != 0 && comments_[placement].comment_ != 0;
  }

  std::string 
  Value::getComment (CommentPlacement placement) const
  {
    if (hasComment (placement))
      return comments_[placement].comment_;
    return "";
  }


  std::string 
  Value::toStyledString () const
  {
    StyledWriter writer;
    return writer.write (*this);
  }


  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