linguist/samples/C++/json_writer.cpp

// Copyright 2007-2010 Baptiste Lepilleur
// Distributed under MIT license, or public domain if desired and
// recognized in your jurisdiction.
// See file LICENSE for detail or copy at http://jsoncpp.sourceforge.net/LICENSE

/*
Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/

// Source - https://github.com/Ij888/ApacheCordovaRecipes/blob/6e8a2c1d9de7302f74bc3dbac54a021f0499bbb3/jqmsandbox/plugins/cordova-plugin-globalization/src/blackberry10/native/public/json_writer.cpp

#include <json/writer.h>
#include <utility>
#include <assert.h>
#include <stdio.h>
#include <string.h>
#include <iostream>
#include <sstream>
#include <iomanip>

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

namespace Json {

static bool isControlCharacter(char ch)
{
   return ch > 0 && ch <= 0x1F;
}

static bool containsControlCharacter( const char* str )
{
   while ( *str ) 
   {
      if ( isControlCharacter( *(str++) ) )
         return true;
   }
   return false;
}
static void uintToString( unsigned int 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( UInt(value), current );
   if ( isNegative )
      *--current = '-';
   assert( current >= buffer );
   return current;
}


std::string valueToString( UInt value )
{
   char buffer[32];
   char *current = buffer + sizeof(buffer);
   uintToString( value, current );
   assert( current >= buffer );
   return current;
}

std::string valueToString( double value )
{
   char buffer[32];
#if defined(_MSC_VER) && defined(__STDC_SECURE_LIB__) // Use secure version with visual studio 2005 to avoid warning. 
   sprintf_s(buffer, sizeof(buffer), "%#.16g", value); 
#else	
   sprintf(buffer, "%#.16g", value); 
#endif
   char* ch = buffer + strlen(buffer) - 1;
   if (*ch != '0') return buffer; // nothing to truncate, so save time
   while(ch > buffer && *ch == '0'){
     --ch;
   }
   char* last_nonzero = ch;
   while(ch >= buffer){
     switch(*ch){
     case '0':
     case '1':
     case '2':
     case '3':
     case '4':
     case '5':
     case '6':
     case '7':
     case '8':
     case '9':
       --ch;
       continue;
     case '.':
       // Truncate zeroes to save bytes in output, but keep one.
       *(last_nonzero+2) = '\0';
       return buffer;
     default:
       return buffer;
     }
   }
   return buffer;
}


std::string valueToString( bool value )
{
   return value ? "true" : "false";
}

std::string valueToQuotedString( const char *value )
{
   // Not sure how to handle unicode...
   if (strpbrk(value, "\"\\\b\f\n\r\t") == NULL && !containsControlCharacter( value ))
      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 (const char* 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.
            // blep notes: actually escaping \/ may be useful in javascript to avoid </ 
            // sequence.
            // Should add a flag to allow this compatibility mode and prevent this 
            // sequence from occurring.
         default:
            if ( isControlCharacter( *c ) )
            {
               std::ostringstream oss;
               oss << "\\u" << std::hex << std::uppercase << std::setfill('0') << std::setw(4) << static_cast<int>(*c);
               result += oss.str();
            }
            else
            {
               result += *c;
            }
            break;
      }
   }
   result += "\"";
   return result;
}

// Class Writer
// //////////////////////////////////////////////////////////////////
Writer::~Writer()
{
}


// Class FastWriter
// //////////////////////////////////////////////////////////////////

FastWriter::FastWriter()
   : yamlCompatiblityEnabled_( false )
{
}


void 
FastWriter::enableYAMLCompatibility()
{
   yamlCompatiblityEnabled_ = true;
}


std::string 
FastWriter::write( const Value &root )
{
   document_ = "";
   writeValue( root );
   document_ += "\n";
   return document_;
}


void 
FastWriter::writeValue( const Value &value )
{
   switch ( value.type() )
   {
   case nullValue:
      document_ += "null";
      break;
   case intValue:
      document_ += valueToString( value.asInt() );
      break;
   case uintValue:
      document_ += valueToString( value.asUInt() );
      break;
   case realValue:
      document_ += valueToString( value.asDouble() );
      break;
   case stringValue:
      document_ += valueToQuotedString( value.asCString() );
      break;
   case booleanValue:
      document_ += valueToString( value.asBool() );
      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_ += yamlCompatiblityEnabled_ ? ": " 
                                                  : ":";
            writeValue( value[name] );
         }
         document_ += "}";
      }
      break;
   }
}


// Class StyledWriter
// //////////////////////////////////////////////////////////////////

StyledWriter::StyledWriter()
   : rightMargin_( 74 )
   , indentSize_( 3 )
{
}


std::string 
StyledWriter::write( const Value &root )
{
   document_ = "";
   addChildValues_ = false;
   indentString_ = "";
   writeCommentBeforeValue( root );
   writeValue( root );
   writeCommentAfterValueOnSameLine( root );
   document_ += "\n";
   return document_;
}


void 
StyledWriter::writeValue( const Value &value )
{
   switch ( value.type() )
   {
   case nullValue:
      pushValue( "null" );
      break;
   case intValue:
      pushValue( valueToString( value.asInt() ) );
      break;
   case uintValue:
      pushValue( valueToString( value.asUInt() ) );
      break;
   case realValue:
      pushValue( valueToString( value.asDouble() ) );
      break;
   case stringValue:
      pushValue( valueToQuotedString( value.asCString() ) );
      break;
   case booleanValue:
      pushValue( valueToString( value.asBool() ) );
      break;
   case arrayValue:
      writeArrayValue( value);
      break;
   case objectValue:
      {
         Value::Members members( value.getMemberNames() );
         if ( members.empty() )
            pushValue( "{}" );
         else
         {
            writeWithIndent( "{" );
            indent();
            Value::Members::iterator it = members.begin();
            while ( true )
            {
               const std::string &name = *it;
               const Value &childValue = value[name];
               writeCommentBeforeValue( childValue );
               writeWithIndent( valueToQuotedString( name.c_str() ) );
               document_ += " : ";
               writeValue( childValue );
               if ( ++it == members.end() )
               {
                  writeCommentAfterValueOnSameLine( childValue );
                  break;
               }
               document_ += ",";
               writeCommentAfterValueOnSameLine( childValue );
            }
            unindent();
            writeWithIndent( "}" );
         }
      }
      break;
   }
}


void 
StyledWriter::writeArrayValue( const Value &value )
{
   unsigned size = value.size();
   if ( size == 0 )
      pushValue( "[]" );
   else
   {
      bool isArrayMultiLine = isMultineArray( value );
      if ( isArrayMultiLine )
      {
         writeWithIndent( "[" );
         indent();
         bool hasChildValue = !childValues_.empty();
         unsigned index =0;
         while ( true )
         {
            const Value &childValue = value[index];
            writeCommentBeforeValue( childValue );
            if ( hasChildValue )
               writeWithIndent( childValues_[index] );
            else
            {
               writeIndent();
               writeValue( childValue );
            }
            if ( ++index == size )
            {
               writeCommentAfterValueOnSameLine( childValue );
               break;
            }
            document_ += ",";
            writeCommentAfterValueOnSameLine( childValue );
         }
         unindent();
         writeWithIndent( "]" );
      }
      else // output on a single line
      {
         assert( childValues_.size() == size );
         document_ += "[ ";
         for ( unsigned index =0; index < size; ++index )
         {
            if ( index > 0 )
               document_ += ", ";
            document_ += childValues_[index];
         }
         document_ += " ]";
      }
   }
}


bool 
StyledWriter::isMultineArray( const Value &value )
{
   int size = value.size();
   bool isMultiLine = size*3 >= rightMargin_ ;
   childValues_.clear();
   for ( int index =0; index < size  &&  !isMultiLine; ++index )
   {
      const Value &childValue = value[index];
      isMultiLine = isMultiLine  ||
                     ( (childValue.isArray()  ||  childValue.isObject())  &&  
                        childValue.size() > 0 );
   }
   if ( !isMultiLine ) // check if line length > max line length
   {
      childValues_.reserve( size );
      addChildValues_ = true;
      int lineLength = 4 + (size-1)*2; // '[ ' + ', '*n + ' ]'
      for ( int index =0; index < size  &&  !isMultiLine; ++index )
      {
         writeValue( value[index] );
         lineLength += int( childValues_[index].length() );
         isMultiLine = isMultiLine  &&  hasCommentForValue( value[index] );
      }
      addChildValues_ = false;
      isMultiLine = isMultiLine  ||  lineLength >= rightMargin_;
   }
   return isMultiLine;
}


void 
StyledWriter::pushValue( const std::string &value )
{
   if ( addChildValues_ )
      childValues_.push_back( value );
   else
      document_ += value;
}


void 
StyledWriter::writeIndent()
{
   if ( !document_.empty() )
   {
      char last = document_[document_.length()-1];
      if ( last == ' ' )     // already indented
         return;
      if ( last != '\n' )    // Comments may add new-line
         document_ += '\n';
   }
   document_ += indentString_;
}


void 
StyledWriter::writeWithIndent( const std::string &value )
{
   writeIndent();
   document_ += value;
}


void 
StyledWriter::indent()
{
   indentString_ += std::string( indentSize_, ' ' );
}


void 
StyledWriter::unindent()
{
   assert( int(indentString_.size()) >= indentSize_ );
   indentString_.resize( indentString_.size() - indentSize_ );
}


void 
StyledWriter::writeCommentBeforeValue( const Value &root )
{
   if ( !root.hasComment( commentBefore ) )
      return;
   document_ += normalizeEOL( root.getComment( commentBefore ) );
   document_ += "\n";
}


void 
StyledWriter::writeCommentAfterValueOnSameLine( const Value &root )
{
   if ( root.hasComment( commentAfterOnSameLine ) )
      document_ += " " + normalizeEOL( root.getComment( commentAfterOnSameLine ) );

   if ( root.hasComment( commentAfter ) )
   {
      document_ += "\n";
      document_ += normalizeEOL( root.getComment( commentAfter ) );
      document_ += "\n";
   }
}


bool 
StyledWriter::hasCommentForValue( const Value &value )
{
   return value.hasComment( commentBefore )
          ||  value.hasComment( commentAfterOnSameLine )
          ||  value.hasComment( commentAfter );
}


std::string 
StyledWriter::normalizeEOL( const std::string &text )
{
   std::string normalized;
   normalized.reserve( text.length() );
   const char *begin = text.c_str();
   const char *end = begin + text.length();
   const char *current = begin;
   while ( current != end )
   {
      char c = *current++;
      if ( c == '\r' ) // mac or dos EOL
      {
         if ( *current == '\n' ) // convert dos EOL
            ++current;
         normalized += '\n';
      }
      else // handle unix EOL & other char
         normalized += c;
   }
   return normalized;
}


// Class StyledStreamWriter
// //////////////////////////////////////////////////////////////////

StyledStreamWriter::StyledStreamWriter( std::string indentation )
   : document_(NULL)
   , rightMargin_( 74 )
   , indentation_( indentation )
{
}


void
StyledStreamWriter::write( std::ostream &out, const Value &root )
{
   document_ = &out;
   addChildValues_ = false;
   indentString_ = "";
   writeCommentBeforeValue( root );
   writeValue( root );
   writeCommentAfterValueOnSameLine( root );
   *document_ << "\n";
   document_ = NULL; // Forget the stream, for safety.
}


void 
StyledStreamWriter::writeValue( const Value &value )
{
   switch ( value.type() )
   {
   case nullValue:
      pushValue( "null" );
      break;
   case intValue:
      pushValue( valueToString( value.asInt() ) );
      break;
   case uintValue:
      pushValue( valueToString( value.asUInt() ) );
      break;
   case realValue:
      pushValue( valueToString( value.asDouble() ) );
      break;
   case stringValue:
      pushValue( valueToQuotedString( value.asCString() ) );
      break;
   case booleanValue:
      pushValue( valueToString( value.asBool() ) );
      break;
   case arrayValue:
      writeArrayValue( value);
      break;
   case objectValue:
      {
         Value::Members members( value.getMemberNames() );
         if ( members.empty() )
            pushValue( "{}" );
         else
         {
            writeWithIndent( "{" );
            indent();
            Value::Members::iterator it = members.begin();
            while ( true )
            {
               const std::string &name = *it;
               const Value &childValue = value[name];
               writeCommentBeforeValue( childValue );
               writeWithIndent( valueToQuotedString( name.c_str() ) );
               *document_ << " : ";
               writeValue( childValue );
               if ( ++it == members.end() )
               {
                  writeCommentAfterValueOnSameLine( childValue );
                  break;
               }
               *document_ << ",";
               writeCommentAfterValueOnSameLine( childValue );
            }
            unindent();
            writeWithIndent( "}" );
         }
      }
      break;
   }
}


void 
StyledStreamWriter::writeArrayValue( const Value &value )
{
   unsigned size = value.size();
   if ( size == 0 )
      pushValue( "[]" );
   else
   {
      bool isArrayMultiLine = isMultineArray( value );
      if ( isArrayMultiLine )
      {
         writeWithIndent( "[" );
         indent();
         bool hasChildValue = !childValues_.empty();
         unsigned index =0;
         while ( true )
         {
            const Value &childValue = value[index];
            writeCommentBeforeValue( childValue );
            if ( hasChildValue )
               writeWithIndent( childValues_[index] );
            else
            {
	       writeIndent();
               writeValue( childValue );
            }
            if ( ++index == size )
            {
               writeCommentAfterValueOnSameLine( childValue );
               break;
            }
            *document_ << ",";
            writeCommentAfterValueOnSameLine( childValue );
         }
         unindent();
         writeWithIndent( "]" );
      }
      else // output on a single line
      {
         assert( childValues_.size() == size );
         *document_ << "[ ";
         for ( unsigned index =0; index < size; ++index )
         {
            if ( index > 0 )
               *document_ << ", ";
            *document_ << childValues_[index];
         }
         *document_ << " ]";
      }
   }
}


bool 
StyledStreamWriter::isMultineArray( const Value &value )
{
   int size = value.size();
   bool isMultiLine = size*3 >= rightMargin_ ;
   childValues_.clear();
   for ( int index =0; index < size  &&  !isMultiLine; ++index )
   {
      const Value &childValue = value[index];
      isMultiLine = isMultiLine  ||
                     ( (childValue.isArray()  ||  childValue.isObject())  &&  
                        childValue.size() > 0 );
   }
   if ( !isMultiLine ) // check if line length > max line length
   {
      childValues_.reserve( size );
      addChildValues_ = true;
      int lineLength = 4 + (size-1)*2; // '[ ' + ', '*n + ' ]'
      for ( int index =0; index < size  &&  !isMultiLine; ++index )
      {
         writeValue( value[index] );
         lineLength += int( childValues_[index].length() );
         isMultiLine = isMultiLine  &&  hasCommentForValue( value[index] );
      }
      addChildValues_ = false;
      isMultiLine = isMultiLine  ||  lineLength >= rightMargin_;
   }
   return isMultiLine;
}


void 
StyledStreamWriter::pushValue( const std::string &value )
{
   if ( addChildValues_ )
      childValues_.push_back( value );
   else
      *document_ << value;
}


void 
StyledStreamWriter::writeIndent()
{
  /*
    Some comments in this method would have been nice. ;-)

   if ( !document_.empty() )
   {
      char last = document_[document_.length()-1];
      if ( last == ' ' )     // already indented
         return;
      if ( last != '\n' )    // Comments may add new-line
         *document_ << '\n';
   }
  */
   *document_ << '\n' << indentString_;
}


void 
StyledStreamWriter::writeWithIndent( const std::string &value )
{
   writeIndent();
   *document_ << value;
}


void 
StyledStreamWriter::indent()
{
   indentString_ += indentation_;
}


void 
StyledStreamWriter::unindent()
{
   assert( indentString_.size() >= indentation_.size() );
   indentString_.resize( indentString_.size() - indentation_.size() );
}


void 
StyledStreamWriter::writeCommentBeforeValue( const Value &root )
{
   if ( !root.hasComment( commentBefore ) )
      return;
   *document_ << normalizeEOL( root.getComment( commentBefore ) );
   *document_ << "\n";
}


void 
StyledStreamWriter::writeCommentAfterValueOnSameLine( const Value &root )
{
   if ( root.hasComment( commentAfterOnSameLine ) )
      *document_ << " " + normalizeEOL( root.getComment( commentAfterOnSameLine ) );

   if ( root.hasComment( commentAfter ) )
   {
      *document_ << "\n";
      *document_ << normalizeEOL( root.getComment( commentAfter ) );
      *document_ << "\n";
   }
}


bool 
StyledStreamWriter::hasCommentForValue( const Value &value )
{
   return value.hasComment( commentBefore )
          ||  value.hasComment( commentAfterOnSameLine )
          ||  value.hasComment( commentAfter );
}


std::string 
StyledStreamWriter::normalizeEOL( const std::string &text )
{
   std::string normalized;
   normalized.reserve( text.length() );
   const char *begin = text.c_str();
   const char *end = begin + text.length();
   const char *current = begin;
   while ( current != end )
   {
      char c = *current++;
      if ( c == '\r' ) // mac or dos EOL
      {
         if ( *current == '\n' ) // convert dos EOL
            ++current;
         normalized += '\n';
      }
      else // handle unix EOL & other char
         normalized += c;
   }
   return normalized;
}


std::ostream& operator<<( std::ostream &sout, const Value &root )
{
   Json::StyledStreamWriter writer;
   writer.write(sout, root);
   return sout;
}


} // namespace Json