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//
// Copyright (C) 2002 RealVNC Ltd. All Rights Reserved.
//
// This is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This software is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this software; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
// USA.
//
// rdr::InStream marshalls data from a buffer stored in RDR (RFB Data
// Representation).
//
#ifndef __RDR_INSTREAM_H__
#define __RDR_INSTREAM_H__
#include <rdr/types.h>
#include <string.h> // for memcpy
namespace rdr {
class InStream {
public:
virtual ~InStream() {}
// check() ensures there is buffer data for at least one item of size
// itemSize bytes. Returns the number of items in the buffer (up to a
// maximum of nItems).
inline int check(int itemSize, int nItems=1)
{
if (ptr + itemSize * nItems > end) {
if (ptr + itemSize > end)
return overrun(itemSize, nItems);
nItems = (end - ptr) / itemSize;
}
return nItems;
}
// readU/SN() methods read unsigned and signed N-bit integers.
inline U8 readU8() { check(1); return *ptr++; }
inline U16 readU16() { check(2); int b0 = *ptr++; int b1 = *ptr++;
return b0 << 8 | b1; }
inline U32 readU32() { check(4); int b0 = *ptr++; int b1 = *ptr++;
int b2 = *ptr++; int b3 = *ptr++;
return b0 << 24 | b1 << 16 | b2 << 8 | b3; }
inline S8 readS8() { return (S8) readU8(); }
inline S16 readS16() { return (S16)readU16(); }
inline S32 readS32() { return (S32)readU32(); }
// readString() reads a string - a U32 length followed by the data.
// Returns a null-terminated string - the caller should delete[] it
// afterwards.
char* readString();
// maxStringLength protects against allocating a huge buffer. Set it
// higher if you need longer strings.
static U32 maxStringLength;
inline void skip(int bytes) {
while (bytes > 0) {
int n = check(1, bytes);
ptr += n;
bytes -= n;
}
}
// readBytes() reads an exact number of bytes.
virtual void readBytes(void* data, int length) {
U8* dataPtr = (U8*)data;
U8* dataEnd = dataPtr + length;
while (dataPtr < dataEnd) {
int n = check(1, dataEnd - dataPtr);
memcpy(dataPtr, ptr, n);
ptr += n;
dataPtr += n;
}
}
// readOpaqueN() reads a quantity without byte-swapping.
inline U8 readOpaque8() { return readU8(); }
inline U16 readOpaque16() { check(2); U16 r; ((U8*)&r)[0] = *ptr++;
((U8*)&r)[1] = *ptr++; return r; }
inline U32 readOpaque32() { check(4); U32 r; ((U8*)&r)[0] = *ptr++;
((U8*)&r)[1] = *ptr++; ((U8*)&r)[2] = *ptr++;
((U8*)&r)[3] = *ptr++; return r; }
inline U32 readOpaque24A() { check(3); U32 r=0; ((U8*)&r)[0] = *ptr++;
((U8*)&r)[1] = *ptr++; ((U8*)&r)[2] = *ptr++;
return r; }
inline U32 readOpaque24B() { check(3); U32 r=0; ((U8*)&r)[1] = *ptr++;
((U8*)&r)[2] = *ptr++; ((U8*)&r)[3] = *ptr++;
return r; }
// pos() returns the position in the stream.
virtual int pos() = 0;
// getptr(), getend() and setptr() are "dirty" methods which allow you to
// manipulate the buffer directly. This is useful for a stream which is a
// wrapper around an underlying stream.
inline const U8* getptr() const { return ptr; }
inline const U8* getend() const { return end; }
inline void setptr(const U8* p) { ptr = p; }
private:
// overrun() is implemented by a derived class to cope with buffer overrun.
// It ensures there are at least itemSize bytes of buffer data. Returns
// the number of items in the buffer (up to a maximum of nItems). itemSize
// is supposed to be "small" (a few bytes).
virtual int overrun(int itemSize, int nItems) = 0;
protected:
InStream() {}
const U8* ptr;
const U8* end;
};
}
#endif
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