Initial commit

common/rdr/FdInStream.cxx

@@ -0,0 +1,260 @@
+/* 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.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <sys/time.h>
+#ifdef _WIN32
+#include <winsock2.h>
+#define close closesocket
+#undef errno
+#define errno WSAGetLastError()
+#include <os/winerrno.h>
+#else
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <unistd.h>
+#endif
+
+#ifndef vncmin
+#define vncmin(a,b)            (((a) < (b)) ? (a) : (b))
+#endif
+#ifndef vncmax
+#define vncmax(a,b)            (((a) > (b)) ? (a) : (b))
+#endif
+
+/* Old systems have select() in sys/time.h */
+#ifdef HAVE_SYS_SELECT_H
+#include <sys/select.h>
+#endif
+
+#include <rdr/FdInStream.h>
+#include <rdr/Exception.h>
+
+using namespace rdr;
+
+enum { DEFAULT_BUF_SIZE = 8192,
+       MIN_BULK_SIZE = 1024 };
+
+FdInStream::FdInStream(int fd_, int timeoutms_, int bufSize_,
+                       bool closeWhenDone_)
+  : fd(fd_), closeWhenDone(closeWhenDone_),
+    timeoutms(timeoutms_), blockCallback(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_, FdInStreamBlockCallback* blockCallback_,
+                       int bufSize_)
+  : fd(fd_), timeoutms(0), blockCallback(blockCallback_),
+    timing(false), timeWaitedIn100us(5), timedKbits(0),
+    bufSize(bufSize_ ? bufSize_ : DEFAULT_BUF_SIZE), offset(0)
+{
+  ptr = end = start = new U8[bufSize];
+}
+
+FdInStream::~FdInStream()
+{
+  delete [] start;
+  if (closeWhenDone) close(fd);
+}
+
+
+void FdInStream::setTimeout(int timeoutms_) {
+  timeoutms = timeoutms_;
+}
+
+void FdInStream::setBlockCallback(FdInStreamBlockCallback* blockCallback_)
+{
+  blockCallback = blockCallback_;
+  timeoutms = 0;
+}
+
+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, bool wait)
+{
+  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;
+
+  int bytes_to_read;
+  while (end < start + itemSize) {
+    bytes_to_read = start + bufSize - end;
+    if (!timing) {
+      // When not timing, we must be careful not to read too much
+      // extra data into the buffer. Otherwise, the line speed
+      // estimation might stay at zero for a long time: All reads
+      // during timing=1 can be satisfied without calling
+      // readWithTimeoutOrCallback. However, reading only 1 or 2 bytes
+      // bytes is ineffecient.
+      bytes_to_read = vncmin(bytes_to_read, vncmax(itemSize*nItems, 8));
+    }
+    int n = readWithTimeoutOrCallback((U8*)end, bytes_to_read, wait);
+    if (n == 0) return 0;
+    end += n;
+  }
+
+  if (itemSize * nItems > end - ptr)
+    nItems = (end - ptr) / itemSize;
+
+  return nItems;
+}
+
+//
+// readWithTimeoutOrCallback() reads up to the given length in bytes from the
+// file descriptor into a buffer.  If the wait argument is false, then zero is
+// returned if no bytes can be read without blocking.  Otherwise if a
+// blockCallback is set, it will be called (repeatedly) instead of blocking.
+// If alternatively there is a timeout set and that timeout expires, it throws
+// a TimedOut exception.  Otherwise it returns the number of bytes read.  It
+// never attempts to recv() unless select() indicates that the fd is readable -
+// this means it can be used on an fd which has been set non-blocking.  It also
+// has to cope with the annoying possibility of both select() and recv()
+// returning EINTR.
+//
+
+int FdInStream::readWithTimeoutOrCallback(void* buf, int len, bool wait)
+{
+  struct timeval before, after;
+  if (timing)
+    gettimeofday(&before, 0);
+
+  int n;
+  while (true) {
+    do {
+      fd_set fds;
+      struct timeval tv;
+      struct timeval* tvp = &tv;
+
+      if (!wait) {
+        tv.tv_sec = tv.tv_usec = 0;
+      } else if (timeoutms != -1) {
+        tv.tv_sec = timeoutms / 1000;
+        tv.tv_usec = (timeoutms % 1000) * 1000;
+      } else {
+        tvp = 0;
+      }
+
+      FD_ZERO(&fds);
+      FD_SET(fd, &fds);
+      n = select(fd+1, &fds, 0, 0, tvp);
+    } while (n < 0 && errno == EINTR);
+
+    if (n > 0) break;
+    if (n < 0) throw SystemException("select",errno);
+    if (!wait) return 0;
+    if (!blockCallback) throw TimedOut();
+
+    blockCallback->blockCallback();
+  }
+
+  do {
+    n = ::recv(fd, (char*)buf, len, 0);
+  } while (n < 0 && errno == EINTR);
+
+  if (n < 0) throw SystemException("read",errno);
+  if (n == 0) throw EndOfStream();
+
+  if (timing) {
+    gettimeofday(&after, 0);
+    int newTimeWaited = ((after.tv_sec - before.tv_sec) * 10000 +
+                         (after.tv_usec - before.tv_usec) / 100);
+    int newKbits = n * 8 / 1000;
+
+    // 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;
+}