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- /* Copyright (C) 2002-2005 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 <rdr/Exception.h>
- #include <string.h> // for memcpy
-
- namespace rdr {
-
- class InStream {
-
- public:
-
- virtual ~InStream() {}
-
- // avail() returns the number of bytes that are currenctly directly
- // available from the stream.
-
- inline size_t avail()
- {
- return end - ptr;
- }
-
- // check() ensures there is buffer data for at least needed bytes. Returns
- // true once the data is available. If wait is false, then instead of
- // blocking to wait for the bytes, false is returned if the bytes are not
- // immediately available.
-
- inline size_t check(size_t needed, bool wait=true)
- {
- if (needed > avail())
- return overrun(needed, wait);
-
- return true;
- }
-
- // checkNoWait() tries to make sure that the given number of bytes can
- // be read without blocking. It returns true if this is the case, false
- // otherwise. The length must be "small" (less than the buffer size).
-
- inline bool checkNoWait(size_t length) { return check(length, false); }
-
- // 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(); }
-
- inline void skip(size_t bytes) {
- while (bytes > 0) {
- size_t n = check(1, bytes);
- ptr += n;
- bytes -= n;
- }
- }
-
- // readBytes() reads an exact number of bytes.
-
- void readBytes(void* data, size_t length) {
- while (length > 0) {
- size_t n = check(1, length);
- memcpy(data, ptr, n);
- ptr += n;
- data = (U8*)data + n;
- length -= 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; }
-
- // pos() returns the position in the stream.
-
- virtual size_t pos() = 0;
-
- // getptr() and setptr() are "dirty" methods which allow you direct access
- // to the buffer. This is useful for a stream which is a wrapper around an
- // some other stream API.
-
- inline const U8* getptr(size_t length) { check(length); return ptr; }
- inline void setptr(size_t length) { if (length > avail())
- throw Exception("Input stream overflow");
- skip(length); }
-
- private:
-
- // overrun() is implemented by a derived class to cope with buffer overrun.
- // It ensures there are at least needed bytes of buffer data. Returns true
- // once the data is available. If wait is false, then instead of blocking
- // to wait for the bytes, false is returned if the bytes are not
- // immediately available.
-
- virtual bool overrun(size_t needed, bool wait=true) = 0;
-
- protected:
-
- InStream() {}
- const U8* ptr;
- const U8* end;
- };
-
- }
-
- #endif
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