Dogcows Code - chaz/yoink/blob - src/Moof/Deserializer.hh

   1
   2 /*******************************************************************************
   3
   4  Copyright (c) 2009, Charles McGarvey
   5  All rights reserved.
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   7  Redistribution   and   use  in  source  and  binary  forms,  with  or  without
   8  modification, are permitted provided that the following conditions are met:
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  10    * Redistributions  of  source  code  must retain the above copyright notice,
  11      this list of conditions and the following disclaimer.
  12    * Redistributions  in binary form must reproduce the above copyright notice,
  13      this  list of conditions and the following disclaimer in the documentation
  14      and/or other materials provided with the distribution.
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  16  THIS  SOFTWARE  IS  PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  17  AND  ANY  EXPRESS  OR  IMPLIED  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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  27 *******************************************************************************/
  28
  29 #ifndef _MOOF_DESERIALIZER_HH_
  30 #define _MOOF_DESERIALIZER_HH_
  31
  32 /**
  33  * @file Deserializer.hh
  34  * Deserialize structures and types from input on a stream.
  35  */
  36
  37 #include <istream>
  38 #include <string>
  39 #include <stdexcept>
  40
  41 #include <boost/shared_ptr.hpp>
  42
  43 #include <Moof/Exception.hh>
  44
  45
  46 namespace Mf {
  47
  48
  49 class Serializable;             // forward declaration
  50 typedef boost::shared_ptr<Serializable> SerializableP;
  51
  52
  53 class Deserializer
  54 {
  55         class Impl;
  56         boost::shared_ptr<Impl> impl_;
  57
  58 public:
  59
  60         /**
  61          * Construction is initialization.  A deserializer can be constructed with
  62          * either an input stream or a string representing a filename that will be
  63          * read from.  If a stream is provided, it will not be closed after parsing,
  64          * but the parser may read past the end of usable bytes, so you should not
  65          * use a deserializer on a stream that you expect to continue to use after
  66          * the deserialization.
  67          * @param comments If true, C and C++-style comments will be allowed and
  68          * ignored by the parser.
  69          * @param check If true, UTF-8 strings will be checked for validity and an
  70          * exception thrown if such a problem exists.  Otherwise strings will not be
  71          * checked.
  72          */
  73
  74         Deserializer(const std::string& filePath, bool comments = false,
  75                         bool check = false);
  76         Deserializer(std::istream& input, bool comments = false, bool check = false);
  77
  78
  79         /**
  80          * Parse the object from of the stream.  The stream is considered to be
  81          * dominated by the parser and may read and discard bytes past the end of
  82          * the actual parsed object.  Only one object can be deserialized by the
  83          * deserializer.
  84          */
  85
  86         SerializableP deserialize();
  87
  88         /**
  89          * Used by serializable objects to parse themselves.  These methods should
  90          * generally not be used directory for deserialization.  This one returns
  91          * the next object in the queue which has been parsed.  This method may
  92          * block if more data is pending and an object has not bee constructed yet.
  93          * The caller takes ownership of the object which has been allocated with
  94          * the new operator and must therefore be sure to delete the object as
  95          * appropriated.  Null (0) will be returned by this method to signify one of
  96          * three things: 1) the end of an array, 2) the end of a map/dictionary, or
  97          * 3) there is nothing more to be obtained.  Container objects will be empty
  98          * and will have to be filled with their contained elements by repeatedly
  99          * calling this method until a null is returned.  This method will continue
 100          * to return the same value until pop() is called which will cause this
 101          * method to return the next object as expected.
 102          */
 103
 104         Serializable* pullNext();
 105
 106         /**
 107          * If the object returned by pullNext() has been received successfully and
 108          * the caller is ready for the next object, this method should be called to
 109          * take that object off of the queue.
 110          */
 111
 112         void pop();
 113
 114
 115         /**
 116          * This exception is thrown upon deserialization errors.
 117          */
 118
 119         struct Exception : public Mf::Exception
 120         {
 121                 enum
 122                 {
 123                         PARSING_FAILED  = 1024
 124                 };
 125
 126                 explicit Exception(unsigned error) :
 127                         Mf::Exception(error) {}
 128
 129                 void raise()
 130                 {
 131                         throw *this;
 132                 }
 133
 134                 const char* what() const throw()
 135                 {
 136                         switch (code)
 137                         {
 138                                 case PARSING_FAILED:
 139                                         return "parsing failed";
 140                         }
 141                         return Mf::Exception::what();
 142                 }
 143         };
 144 };
 145
 146
 147 } // namespace Mf
 148
 149
 150 #endif // _MOOF_DESERIALIZER_HH_
 151
 152 /** vim: set ts=4 sw=4 tw=80: *************************************************/
 153