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https://github.com/kasmtech/KasmVNC.git
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57a3c3bba8
Just have a simply number of bytes argument to avoid a lot of complexity.
152 lines
4.8 KiB
C++
152 lines
4.8 KiB
C++
/* Copyright (C) 2002-2005 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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//
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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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// avail() returns the number of bytes that are currenctly directly
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// available from the stream.
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inline size_t avail()
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{
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return end - ptr;
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}
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// check() ensures there is buffer data for at least needed bytes. Returns
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// true once the data is available. If wait is false, then instead of
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// blocking to wait for the bytes, false is returned if the bytes are not
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// immediately available.
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inline size_t check(size_t needed, bool wait=true)
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{
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if (needed > avail())
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return overrun(needed, wait);
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return true;
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}
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// checkNoWait() tries to make sure that the given number of bytes can
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// be read without blocking. It returns true if this is the case, false
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// otherwise. The length must be "small" (less than the buffer size).
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// If length is zero, checkNoWait() will return true.
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inline bool checkNoWait(size_t length) { return check(length, false); }
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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(size_t bytes) {
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while (bytes > 0) {
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size_t 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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// If length is zero, readBytes() will return immediately.
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void readBytes(void* data, size_t length) {
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while (length > 0) {
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size_t n = check(1, length);
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memcpy(data, ptr, n);
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ptr += n;
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data = (U8*)data + n;
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length -= 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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// pos() returns the position in the stream.
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virtual size_t 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 needed bytes of buffer data. Returns true
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// once the data is available. If wait is false, then instead of blocking
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// to wait for the bytes, false is returned if the bytes are not
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// immediately available.
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virtual bool overrun(size_t needed, bool wait=true) = 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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