json_reader.cpp.svn-base

这是基于jsoncpp项目写扩展功能

#include <json/reader.h>
#include <json/value.h>
#include <utility>
#include <stdio.h>
#include <assert.h>
#include <iostream>
#include <stdexcept>

#if _MSC_VER >= 1400 // VC++ 8.0
#pragma warning( disable : 4996 )   // disable warning about strdup being deprecated.
#endif

namespace Json {

static inline bool 
in( Reader::Char c, Reader::Char c1, Reader::Char c2, Reader::Char c3, Reader::Char c4 )
{
   return c == c1  ||  c == c2  ||  c == c3  ||  c == c4;
}

static inline bool 
in( Reader::Char c, Reader::Char c1, Reader::Char c2, Reader::Char c3, Reader::Char c4, Reader::Char c5 )
{
   return c == c1  ||  c == c2  ||  c == c3  ||  c == c4  ||  c == c5;
}


static bool 
containsNewLine( Reader::Location begin, 
                 Reader::Location end )
{
   for ( ;begin < end; ++begin )
      if ( *begin == '\n'  ||  *begin == '\r' )
         return true;
   return false;
}


// Class Reader
// //////////////////////////////////////////////////////////////////

Reader::Reader()
{
}

bool
Reader::parse( const std::string &document, 
               Value &root,
               bool collectComments )
{
   document_ = document;
   const char *begin = document_.c_str();
   const char *end = begin + document_.length();
   return parse( begin, end, root, collectComments );
}

bool
Reader::parse( std::istream& sin,
               Value &root,
               bool collectComments )
{
   //std::istream_iterator<char> begin(sin);
   //std::istream_iterator<char> end;
   // Those would allow streamed input from a file, if parse() were a
   // template function.

   // Since std::string is reference-counted, this at least does not
   // create an extra copy.
   std::string doc;
   std::getline(sin, doc, (char)EOF);
   return parse( doc, root, collectComments );
}

bool 
Reader::parse( const char *beginDoc, const char *endDoc, 
               Value &root,
               bool collectComments )
{
   begin_ = beginDoc;
   end_ = endDoc;
   collectComments_ = collectComments;
   current_ = begin_;
   lastValueEnd_ = 0;
   lastValue_ = 0;
   commentsBefore_ = "";
   errors_.clear();
   while ( !nodes_.empty() )
      nodes_.pop();
   nodes_.push( &root );
   
   bool successful = readValue();
   Token token;
   skipCommentTokens( token );
   if ( collectComments_  &&  !commentsBefore_.empty() )
      root.setComment( commentsBefore_, commentAfter );
   return successful;
}


bool
Reader::readValue()
{
   Token token;
   skipCommentTokens( token );
   bool successful = true;

   if ( collectComments_  &&  !commentsBefore_.empty() )
   {
      currentValue().setComment( commentsBefore_, commentBefore );
      commentsBefore_ = "";
   }


   switch ( token.type_ )
   {
   case tokenObjectBegin:
      successful = readObject( token );
      break;
   case tokenArrayBegin:
      successful = readArray( token );
      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 );
   }

   if ( collectComments_ )
   {
      lastValueEnd_ = current_;
      lastValue_ = &currentValue();
   }

   return successful;
}


void 
Reader::skipCommentTokens( Token &token )
{
   do
   {
      readToken( token );
   }
   while ( token.type_ == tokenComment );
}


bool 
Reader::expectToken( TokenType type, Token &token, const char *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;
   case '/':
      token.type_ = tokenComment;
      ok = readComment();
      break;
   case '0':
   case '1':
   case '2':
   case '3':
   case '4':
   case '5':
   case '6':
   case '7':
   case '8':
   case '9':
   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;
}


bool
Reader::readComment()
{
   Location commentBegin = current_ - 1;
   Char c = getNextChar();
   bool successful = false;
   if ( c == '*' )
      successful = readCStyleComment();
   else if ( c == '/' )
      successful = readCppStyleComment();
   if ( !successful )
      return false;

   if ( collectComments_ )
   {
      CommentPlacement placement = commentBefore;
      if ( lastValueEnd_  &&  !containsNewLine( lastValueEnd_, commentBegin ) )
      {
         if ( c != '*'  ||  !containsNewLine( commentBegin, current_ ) )
            placement = commentAfterOnSameLine;
      }

      addComment( commentBegin, current_, placement );
   }
   return true;
}


void 
Reader::addComment( Location begin, 
                    Location end, 
                    CommentPlacement placement )
{
   assert( collectComments_ );
   if ( placement == commentAfterOnSameLine )
   {
      assert( lastValue_ != 0 );
      lastValue_->setComment( std::string( begin, end ), placement );
   }
   else
   {
      if ( !commentsBefore_.empty() )
         commentsBefore_ += "\n";
      commentsBefore_ += std::string( begin, end );
   }
}


bool 
Reader::readCStyleComment()
{
   while ( current_ != end_ )
   {
      Char c = getNextChar();
      if ( c == '*'  &&  *current_ == '/' )
         break;
   }
   return getNextChar() == '/';
}


bool 
Reader::readCppStyleComment()
{
   while ( current_ != end_ )
   {
      Char c = getNextChar();
      if (  c == '\r'  ||  c == '\n' )
         break;
   }
   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 == '"';
}