Dogcows Code - chaz/yoink/blob - src/deserializer.hh

   1
   2 /*******************************************************************************
   3
   4  Copyright (c) 2009, Charles McGarvey
   5  All rights reserved.
   6
   7  Redistribution   and   use  in  source  and  binary  forms,  with  or  without
   8  modification, are permitted provided that the following conditions are met:
   9
  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.
  15
  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
  18  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  19  DISCLAIMED.  IN  NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
  20  FOR  ANY  DIRECT,  INDIRECT,  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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  27 *******************************************************************************/
  28
  29 #ifndef _DESERIALIZER_HH_
  30 #define _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
  44 namespace dc {
  45
  46
  47 class serializable;             // forward declaration
  48 typedef boost::shared_ptr<serializable> serializable_ptr;
  49
  50 class deserializer
  51 {
  52 public:
  53
  54         /**
  55          * Construction is initialization.  A deserializer can be constructed with
  56          * either an input stream or a string representing a filename that will be
  57          * read from.  If a stream is provided, it will not be closed after parsing,
  58          * but the parser may read past the end of usable bytes, so you should not
  59          * use a deserializer on a stream that you expect to continue to use after
  60          * the deserialization.
  61          * @param comments If true, C and C++-style comments will be allowed and
  62          * ignored by the parser.
  63          * @param check If true, UTF-8 strings will be checked for validity and an
  64          * exception thrown if such a problem exists.  Otherwise strings will not be
  65          * checked.
  66          */
  67
  68         deserializer(const std::string& filePath, bool comments = false,
  69                         bool check = false);
  70         deserializer(std::istream& input, bool comments = false, bool check = false);
  71
  72
  73         /**
  74          * Parse the object from of the stream.  The stream is considered to be
  75          * dominated by the parser and may read and discard bytes past the end of
  76          * the actual parsed object.  Only one object can be deserialized by the
  77          * deserializer.
  78          */
  79
  80         serializable_ptr deserialize();
  81
  82         /**
  83          * Used by serializable objects to parse themselves.  These methods should
  84          * generally not be used directory for deserialization.  This one returns
  85          * the next object in the queue which has been parsed.  This method may
  86          * block if more data is pending and an object has not bee constructed yet.
  87          * The caller takes ownership of the object which has been allocated with
  88          * the new operator and must therefore be sure to delete the object as
  89          * appropriated.  Null (0) will be returned by this method to signify one of
  90          * three things: 1) the end of an array, 2) the end of a map/dictionary, or
  91          * 3) there is nothing more to be obtained.  Container objects will be empty
  92          * and will have to be filled with their contained elements by repeatedly
  93          * calling this method until a null is returned.  This method will continue
  94          * to return the same value until pop() is called which will cause this
  95          * method to return the next object as expected.
  96          */
  97
  98         serializable* pullNext();
  99
 100         /**
 101          * If the object returned by pullNext() has been received successfully and
 102          * the caller is ready for the next object, this method should be called to
 103          * take that object off of the queue.
 104          */
 105
 106         void pop();
 107
 108
 109         /**
 110          * This exception is thrown upon deserialization errors.
 111          */
 112
 113         struct exception : std::runtime_error
 114         {
 115                 explicit exception(const std::string& what_arg) :
 116                         std::runtime_error(what_arg) {}
 117         };
 118
 119 private:
 120         class deserializer_impl;
 121         boost::shared_ptr<deserializer_impl> impl;
 122 };
 123
 124
 125 } // namespace dc
 126
 127
 128 #endif // _DESERIALIZER_HH_
 129
 130 /** vim: set ts=4 sw=4 tw=80: *************************************************/
 131