ipc/ipcd/util/public/ipcMessageReader.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /* ***** BEGIN LICENSE BLOCK *****
   3  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
   4  *
   5  * The contents of this file are subject to the Mozilla Public License Version
   6  * 1.1 (the "License"); you may not use this file except in compliance with
   7  * the License. You may obtain a copy of the License at
   8  * http://www.mozilla.org/MPL/
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  10  * Software distributed under the License is distributed on an "AS IS" basis,
  11  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  12  * for the specific language governing rights and limitations under the
  13  * License.
  14  *
  15  * The Original Code is Mozilla IPC.
  16  *
  17  * The Initial Developer of the Original Code is
  18  * Netscape Communications Corporation.
  19  * Portions created by the Initial Developer are Copyright (C) 2003
  20  * the Initial Developer. All Rights Reserved.
  21  *
  22  * Contributor(s):
  23  *   Conrad Carlen <ccarlen@netscape.com>
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  25  * Alternatively, the contents of this file may be used under the terms of
  26  * either the GNU General Public License Version 2 or later (the "GPL"), or
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  37  * ***** END LICENSE BLOCK ***** */
  38
  39 #ifndef ipcMessageReader_h__
  40 #define ipcMessageReader_h__
  41
  42 #include "prtypes.h"
  43
  44 //*****************************************************************************
  45 // ipcMessageReader
  46 //
  47 // Reads from a const buffer supplied to it. Does not take ownership of the
  48 // buffer. Bytes are read in native endianess, as ipcMessageWriter writes them
  49 // in native endianess.
  50 //*****************************************************************************
  51
  52 class ipcMessageReader
  53 {
  54 public:
  55                   ipcMessageReader(const PRUint8* inBuffer, PRUint32 bufferSize) :
  56                     mBuf(inBuffer), mBufEnd(inBuffer + bufferSize),
  57                     mBufPtr(mBuf),
  58                     mError(PR_FALSE)
  59                   { }
  60
  61                   ~ipcMessageReader()
  62                   { }
  63
  64                   // Returns PR_TRUE if an error has occured at any point
  65                   // during the lifetime of this object. Any read operation
  66                   // will safely return 0 on an error condition.
  67   PRBool          HasError()
  68                   { return mError; }
  69
  70   PRUint8         GetInt8();
  71   PRUint16        GetInt16();
  72   PRUint32        GetInt32();
  73   PRInt32         GetBytes(void* destBuffer, PRInt32 n);
  74
  75                   // Returns data at the current read position.
  76   const PRUint8*  GetPtr()
  77                   { return mBufPtr; }
  78
  79                   // Returns PR_TRUE if the new position is within the buffer.
  80                   // Returns PR_FALSE and sets error state if not.
  81   PRBool          AdvancePtr(PRInt32 n);
  82
  83 private:
  84   const PRUint8   *mBuf, *mBufEnd;
  85   const PRUint8   *mBufPtr;
  86   PRBool          mError;
  87 };
  88
  89 #endif // ipcMessageReader_h__