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