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libtdevnc/rdr/FdInStream.cxx

252 lines
6.0 KiB

22 years ago
//
// 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.
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <sys/types.h>
#ifdef _WIN32
#include <winsock.h>
#include <sys/timeb.h>
#define read(s,b,l) recv(s,(char*)b,l,0)
#undef errno
#define errno WSAGetLastError()
#else
#include <unistd.h>
#include <sys/time.h>
#endif
// XXX should use autoconf HAVE_SYS_SELECT_H
#ifdef _AIX
#include <sys/select.h>
#endif
#include <rdr/FdInStream.h>
#include <rdr/Exception.h>
extern "C" {
extern void rfbLog(const char *format, ...);
}
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using namespace rdr;
enum { DEFAULT_BUF_SIZE = 8192,
MIN_BULK_SIZE = 1024 };
FdInStream::FdInStream(int fd_, int timeout_, int bufSize_)
: fd(fd_), timeout(timeout_), blockCallback(0), blockCallbackArg(0),
timing(false), timeWaitedIn100us(5), timedKbits(0),
bufSize(bufSize_ ? bufSize_ : DEFAULT_BUF_SIZE), offset(0)
{
ptr = end = start = new U8[bufSize];
}
FdInStream::FdInStream(int fd_, void (*blockCallback_)(void*),
void* blockCallbackArg_, int bufSize_)
: fd(fd_), timeout(0), blockCallback(blockCallback_),
blockCallbackArg(blockCallbackArg_),
timing(false), timeWaitedIn100us(5), timedKbits(0),
bufSize(bufSize_ ? bufSize_ : DEFAULT_BUF_SIZE), offset(0)
{
ptr = end = start = new U8[bufSize];
}
FdInStream::~FdInStream()
{
delete [] start;
}
int FdInStream::pos()
{
return offset + ptr - start;
}
void FdInStream::readBytes(void* data, int length)
{
if (length < MIN_BULK_SIZE) {
InStream::readBytes(data, length);
return;
}
U8* dataPtr = (U8*)data;
int n = end - ptr;
if (n > length) n = length;
memcpy(dataPtr, ptr, n);
dataPtr += n;
length -= n;
ptr += n;
while (length > 0) {
n = readWithTimeoutOrCallback(dataPtr, length);
dataPtr += n;
length -= n;
offset += n;
}
}
int FdInStream::overrun(int itemSize, int nItems)
{
if (itemSize > bufSize)
throw Exception("FdInStream overrun: max itemSize exceeded");
if (end - ptr != 0)
memmove(start, ptr, end - ptr);
offset += ptr - start;
end -= ptr - start;
ptr = start;
while (end < start + itemSize) {
int n = readWithTimeoutOrCallback((U8*)end, start + bufSize - end);
end += n;
}
if (itemSize * nItems > end - ptr)
nItems = (end - ptr) / itemSize;
return nItems;
}
int FdInStream::checkReadable(int fd, int timeout)
{
while (true) {
fd_set rfds;
struct timeval tv;
tv.tv_sec = timeout / 1000;
tv.tv_usec = (timeout % 1000) * 1000;
FD_ZERO(&rfds);
FD_SET(fd, &rfds);
int n = select(fd+1, &rfds, 0, 0, &tv);
if (n != -1 || errno != EINTR)
return n;
rfbLog("select returned EINTR\n");
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}
}
#ifdef _WIN32
static void gettimeofday(struct timeval* tv, void*)
{
LARGE_INTEGER counts, countsPerSec;
static double usecPerCount = 0.0;
if (QueryPerformanceCounter(&counts)) {
if (usecPerCount == 0.0) {
QueryPerformanceFrequency(&countsPerSec);
usecPerCount = 1000000.0 / countsPerSec.QuadPart;
}
LONGLONG usecs = (LONGLONG)(counts.QuadPart * usecPerCount);
tv->tv_usec = (long)(usecs % 1000000);
tv->tv_sec = (long)(usecs / 1000000);
} else {
struct timeb tb;
ftime(&tb);
tv->tv_sec = tb.time;
tv->tv_usec = tb.millitm * 1000;
}
}
#endif
int FdInStream::readWithTimeoutOrCallback(void* buf, int len)
{
struct timeval before, after;
if (timing)
gettimeofday(&before, 0);
int n = checkReadable(fd, timeout);
if (n < 0) throw SystemException("select",errno);
if (n == 0) {
if (timeout) throw TimedOut();
if (blockCallback) (*blockCallback)(blockCallbackArg);
}
while (true) {
n = ::read(fd, buf, len);
if (n != -1 || errno != EINTR)
break;
rfbLog("read returned EINTR\n");
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}
if (n < 0) throw SystemException("read",errno);
if (n == 0) throw EndOfStream();
if (timing) {
gettimeofday(&after, 0);
// rfbLog("%d.%06d\n",(after.tv_sec - before.tv_sec),
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// (after.tv_usec - before.tv_usec));
int newTimeWaited = ((after.tv_sec - before.tv_sec) * 10000 +
(after.tv_usec - before.tv_usec) / 100);
int newKbits = n * 8 / 1000;
// if (newTimeWaited == 0) {
// rfbLog("new kbps infinite t %d k %d\n",
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// newTimeWaited, newKbits);
// } else {
// rfbLog("new kbps %d t %d k %d\n",
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// newKbits * 10000 / newTimeWaited, newTimeWaited, newKbits);
// }
// limit rate to between 10kbit/s and 40Mbit/s
if (newTimeWaited > newKbits*1000) newTimeWaited = newKbits*1000;
if (newTimeWaited < newKbits/4) newTimeWaited = newKbits/4;
timeWaitedIn100us += newTimeWaited;
timedKbits += newKbits;
}
return n;
}
void FdInStream::startTiming()
{
timing = true;
// Carry over up to 1s worth of previous rate for smoothing.
if (timeWaitedIn100us > 10000) {
timedKbits = timedKbits * 10000 / timeWaitedIn100us;
timeWaitedIn100us = 10000;
}
}
void FdInStream::stopTiming()
{
timing = false;
if (timeWaitedIn100us < timedKbits/2)
timeWaitedIn100us = timedKbits/2; // upper limit 20Mbit/s
}
unsigned int FdInStream::kbitsPerSecond()
{
// The following calculation will overflow 32-bit arithmetic if we have
// received more than about 50Mbytes (400Mbits) since we started timing, so
// it should be OK for a single RFB update.
return timedKbits * 10000 / timeWaitedIn100us;
}