interface/buffer.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        buffer.h
   3 // Purpose:     interface of wxMemoryBuffer
   4 // Author:      wxWidgets team
   5 // RCS-ID:      $Id$
   6 // Licence:     wxWindows license
   7 /////////////////////////////////////////////////////////////////////////////
   8
   9 /**
  10     @class wxMemoryBuffer
  11     @wxheader{buffer.h}
  12
  13     A @b wxMemoryBuffer is a useful data structure for storing arbitrary sized
  14     blocks
  15     of memory. wxMemoryBuffer guarantees deletion of the memory block when the
  16     object
  17     is destroyed.
  18
  19     @library{wxbase}
  20     @category{FIXME}
  21 */
  22 class wxMemoryBuffer
  23 {
  24 public:
  25     //@{
  26     /**
  27         Create a new buffer.
  28
  29         @param size
  30             size of new buffer.
  31     */
  32     wxMemoryBuffer(const wxMemoryBuffer& src);
  33     wxMemoryBuffer(size_t size);
  34     //@}
  35
  36     /**
  37         Append a single byte to the buffer.
  38
  39         @param data
  40             New byte to append to the buffer.
  41     */
  42     void AppendByte(char data);
  43
  44     /**
  45         Ensure that the buffer is big enough and return a pointer to the start
  46         of the empty space in the buffer. This pointer can be used to directly
  47         write data into the buffer, this new data will be appended to
  48         the existing data.
  49
  50         @param sizeNeeded
  51             Amount of extra space required in the buffer for
  52             the append operation
  53     */
  54     void* GetAppendBuf(size_t sizeNeeded);
  55
  56     /**
  57         Returns the size of the buffer.
  58     */
  59     size_t GetBufSize();
  60
  61     /**
  62         Return a pointer to the data in the buffer.
  63     */
  64     void* GetData();
  65
  66     /**
  67         Returns the length of the valid data in the buffer.
  68     */
  69     size_t GetDataLen();
  70
  71     /**
  72         Ensure the buffer is big enough and return a pointer to the
  73         buffer which can be used to directly write into the buffer
  74         up to @a sizeNeeded bytes.
  75     */
  76     void* GetWriteBuf(size_t sizeNeeded);
  77
  78     /**
  79         Ensures the buffer has at least @a size bytes available.
  80     */
  81     void SetBufSize(size_t size);
  82
  83     /**
  84         Sets the length of the data stored in the buffer.  Mainly useful for truncating
  85         existing data.
  86
  87         @param size
  88             New length of the valid data in the buffer. This is
  89             distinct from the allocated size
  90     */
  91     void SetDataLen(size_t size);
  92
  93     /**
  94         Update the length after completing a direct append, which
  95         you must have used GetAppendBuf() to initialise.
  96
  97         @param sizeUsed
  98             This is the amount of new data that has been
  99             appended.
 100     */
 101     void UngetAppendBuf(size_t sizeUsed);
 102
 103     /**
 104         Update the buffer after completing a direct write, which
 105         you must have used GetWriteBuf() to initialise.
 106
 107         @param sizeUsed
 108             The amount of data written in to buffer
 109             by the direct write
 110     */
 111     void UngetWriteBuf(size_t sizeUsed);
 112 };
 113