OutStream.h
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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::OutStream marshalls data into a buffer stored in RDR (RFB Data
// Representation).
//
#ifndef __RDR_OUTSTREAM_H__
#define __RDR_OUTSTREAM_H__
#pragma once
#include "types.h"
#include <string.h> // for memcpy
namespace rdr {
class OutStream {
protected:
OutStream() {}
public:
virtual ~OutStream() {}
// check() ensures there is buffer space for at least one item of size
// itemSize bytes. Returns the number of items which fit (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;
}
// writeU/SN() methods write unsigned and signed N-bit integers.
inline void writeU8( U8 u) { check(1); *ptr++ = u; }
inline void writeU16(U16 u) { check(2); *ptr++ = u >> 8; *ptr++ = (U8)u; }
inline void writeU32(U32 u) { check(4); *ptr++ = u >> 24; *ptr++ = u >> 16;
*ptr++ = u >> 8; *ptr++ = u; }
inline void writeS8( S8 s) { writeU8((U8)s); }
inline void writeS16(S16 s) { writeU16((U16)s); }
inline void writeS32(S32 s) { writeU32((U32)s); }
// writeString() writes a string - a U32 length followed by the data. The
// given string should be null-terminated (but the terminating null is not
// written to the stream).
inline void writeString(const char* str) {
U32 len = strlen(str);
writeU32(len);
writeBytes(str, len);
}
inline void pad(int bytes) {
while (bytes-- > 0) writeU8(0);
}
inline void skip(int bytes) {
while (bytes > 0) {
int n = check(1, bytes);
ptr += n;
bytes -= n;
}
}
// writeBytes() writes an exact number of bytes.
virtual void writeBytes(const void* data, int length) {
const U8* dataPtr = (const U8*)data;
const U8* dataEnd = dataPtr + length;
while (dataPtr < dataEnd) {
int n = check(1, dataEnd - dataPtr);
memcpy(ptr, dataPtr, n);
ptr += n;
dataPtr += n;
}
}
// writeOpaqueN() writes a quantity without byte-swapping.
inline void writeOpaque8( U8 u) { writeU8(u); }
inline void writeOpaque16(U16 u) { check(2); *ptr++ = ((U8*)&u)[0];
*ptr++ = ((U8*)&u)[1]; }
inline void writeOpaque32(U32 u) { check(4); *ptr++ = ((U8*)&u)[0];
*ptr++ = ((U8*)&u)[1];
*ptr++ = ((U8*)&u)[2];
*ptr++ = ((U8*)&u)[3]; }
inline void writeOpaque24A(U32 u) { check(3); *ptr++ = ((U8*)&u)[0];
*ptr++ = ((U8*)&u)[1];
*ptr++ = ((U8*)&u)[2]; }
inline void writeOpaque24B(U32 u) { check(3); *ptr++ = ((U8*)&u)[1];
*ptr++ = ((U8*)&u)[2];
*ptr++ = ((U8*)&u)[3]; }
// length() returns the length of the stream.
virtual int length() = 0;
// flush() requests that the stream be flushed.
virtual void flush() {}
// 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 U8* getptr() { return ptr; }
inline U8* getend() { return end; }
inline void setptr(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 space. Returns
// the number of items which fit (up to a maximum of nItems). itemSize is
// supposed to be "small" (a few bytes).
virtual int overrun(int itemSize, int nItems) = 0;
protected:
U8* ptr;
U8* end;
};
}
#endif