# gdcmByteBuffer.h

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    00001 /*=========================================================================
    00002
    00003   Program: GDCM (Grassroots DICOM). A DICOM library
    00004   Module:  $URL$
    00005
    00006   Copyright (c) 2006-2010 Mathieu Malaterre
    00007   All rights reserved.
    00008   See Copyright.txt or http://gdcm.sourceforge.net/Copyright.html for details.
    00009
    00010      This software is distributed WITHOUT ANY WARRANTY; without even
    00011      the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
    00012      PURPOSE.  See the above copyright notice for more information.
    00013
    00014 =========================================================================*/
    00015 #ifndef GDCMBYTEBUFFER_H
    00016 #define GDCMBYTEBUFFER_H
    00017
    00018 #include "gdcmTypes.h"
    00019 #include <vector>
    00020 #include <assert.h>
    00021 #include <string.h> // memmove
    00022
    00023 #error should not be used
    00024
    00025 namespace gdcm
    00026 {
    00035 class ByteBuffer
    00036 {
    00037   static const int InitBufferSize = 1024;
    00038 public:
    00039   ByteBuffer() : Start(0), End(0),Limit(0) {}
    00040   char *Get(int len)
    00041     {
    00042     char *buffer = &Internal[0];
    00043     if (len > Limit - End)
    00044       {
    00045       // FIXME avoid integer overflow
    00046       int neededSize = len + (End - Start);
    00047       if (neededSize  <= Limit - buffer)
    00048         {
    00049         memmove(buffer, Start, End - Start);
    00050         End = buffer + (End - Start);
    00051         Start = buffer;
    00052         }
    00053       else
    00054         {
    00055         char *newBuf;
    00056         int bufferSize = Limit - Start;
    00057         if ( bufferSize == 0 )
    00058           {
    00059           bufferSize = InitBufferSize;
    00060           }
    00061         do
    00062           {
    00063           bufferSize *= 2;
    00064           } while (bufferSize < neededSize);
    00065         //newBuf = malloc(bufferSize);
    00066         try
    00067           {
    00068           Internal.reserve(bufferSize);
    00069           newBuf = &Internal[0];
    00070           }
    00071         catch(...)
    00072           {
    00073           //errorCode = NoMemoryError;
    00074           return 0;
    00075           }
    00076         Limit = newBuf + bufferSize;
    00077
    00078         if (Start)
    00079           {
    00080           memcpy(newBuf, Start, End - Start);
    00081           }
    00082         End = newBuf + (End - Start);
    00083         Start = /*buffer =*/ newBuf;
    00084         }
    00085       }
    00086     assert( (int)Internal.capacity() >= len );
    00087     return End;
    00088     }
    00089
    00090   void UpdatePosition() {}
    00091   void ShiftEnd(int len) {
    00092     End += len;
    00093   }
    00094   const char *GetStart() const {
    00095     return Start;
    00096   }
    00097
    00098 private:
    00099   typedef std::vector<char> CharVector;
    00100   const char *Start;
    00101         char *End;
    00102   const char *Limit;
    00103   CharVector Internal;
    00104 };
    00105
    00106 } // end namespace gdcm
    00107
    00108 #endif //GDCMBYTEBUFFER_H