Blinker

implemented base class for I/O objects
Parent b3b45af
Stefan Schuermans

Stefan Schuermans commited on 2011-10-25 18:34:13
Showing 4 changed files, with 170 additions and 0 deletions.

src/linux/Io.cpp
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+/* Blinker
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+   Copyright 2011 Stefan Schuermans <stefan@blinkenarea.org>
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+   Copyleft GNU public license - http://www.gnu.org/copyleft/gpl.html
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+   a blinkenarea.org project */
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+
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+#include <set>
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+#include <sys/select.h>
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+
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+#include "Io.h"
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+#include "Time.h"
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+
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+namespace Blinker {
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+
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+/**
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+ * @brief wait for I/O events
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+ * @param[in] read I/O objects to check for readability
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+ * @param[out] read I/O objects that are readable
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+ * @param[in] write I/O objects to check for writability
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+ * @param[out] write I/O objects that are writable
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+ * @param[in] timeout maximum time to wait
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+ */
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+void Io::wait(Set &read, Set &write, const Time &timeout)
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+{
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+  // get maximum file descriptor, read set and write set
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+  int max = 0;
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+  fd_set fd_rd;
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+  FD_ZERO(&fd_rd);
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+  for (Set::const_iterator it = read.begin(); it != read.end(); ++it) {
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+    if ((*it)->m_fd > max)
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+      max = (*it)->m_fd;
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+    FD_SET((*it)->m_fd, &fd_rd);
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+  }
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+  fd_set fd_wr;
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+  FD_ZERO(&fd_wr);
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+  for (Set::const_iterator it = write.begin(); it != write.end(); ++it) {
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+    if ((*it)->m_fd > max)
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+      max = (*it)->m_fd;
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+    FD_SET((*it)->m_fd, &fd_wr);
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+  }
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+
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+  // get timeout
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+  struct timeval to;
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+  timeout.toTimeval(to);
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+
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+  // wait for I/O event
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+  fd_set fd_err;
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+  FD_ZERO(&fd_err);
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+  int res = select(max + 1, &fd_rd, &fd_wr, &fd_err, &to);
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+
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+  // error or timeout
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+  if (res <= 0) {
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+    // return with empty sets
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+    read.clear();
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+    write.clear();
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+    return;
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+  }
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+
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+  // remove file descriptors without event pending from sets
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+  Set::iterator it;
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+  it = read.begin();
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+  while (it != read.end()) {
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+    if (FD_ISSET((*it)->m_fd, &fd_rd)) {
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+      ++it;
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+    } else {
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+      Set::iterator del = it;
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+      ++it;
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+      read.erase(del);
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+    }
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+  } // while it
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+  it = write.begin();
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+  while (it != write.end()) {
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+    if (FD_ISSET((*it)->m_fd, &fd_wr)) {
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+      ++it;
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+    } else {
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+      Set::iterator del = it;
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+      ++it;
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+      write.erase(del);
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+    }
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+  } // while it
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+}
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+
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+/// constructor
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+Io::Io():
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+  m_fd(-1)
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+{
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+}
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+
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+} // namespace Blinker
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+
src/linux/Io.h
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@@ -0,0 +1,51 @@
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+/* Blinker
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+   Copyright 2011 Stefan Schuermans <stefan@blinkenarea.org>
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+   Copyleft GNU public license - http://www.gnu.org/copyleft/gpl.html
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+   a blinkenarea.org project */
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+
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+#ifndef IO_H
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+#define IO_H
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+
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+#include <set>
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+
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+#include "Time.h"
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+
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+namespace Blinker {
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+
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+/// base class for I/O objects
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+class Io
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+{
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+public:
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+  /// set of I/O objects
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+  typedef std::set<Io *> Set;
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+
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+public:
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+  /**
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+   * @brief wait for I/O events
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+   * @param[in] read I/O objects to check for readability
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+   * @param[out] read I/O objects that are readable
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+   * @param[in] write I/O objects to check for writability
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+   * @param[out] write I/O objects that are writable
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+   * @param[in] timeout maximum time to wait
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+   */
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+  static void wait(Set &read, Set &write, const Time &timeout);
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+
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+public:
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+  /// constructor
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+  Io();
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+
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+private:
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+  /// copy constructor disabled
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+  Io(const Io &that);
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+
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+  /// assignment operator disabled
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+  const Io & operator=(const Io &that);
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+
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+protected:
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+  int m_fd; ///< file descriptor
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+}; // class Io
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+
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+} // namespace Blinker
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+
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+#endif // #ifndef IO_H
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+
src/linux/Time.cpp
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... ... 
@@ -159,6 +159,29 @@ time_t Time::toSec() const
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     return m_sec;
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 }
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+/**
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+ * @brief convert to struct timeval
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+ * @param[out] tv struct timeval
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+ */
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+void Time::toTimeval(struct timeval &tv) const
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+{
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+  if (m_sec >= 0) {
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+    tv.tv_sec = m_sec;
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+    tv.tv_usec = (m_ns + 500) / 1000;
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+    if (tv.tv_usec >= 1000000) {
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+      ++tv.tv_sec;
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+      tv.tv_usec -= 1000000;
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+    }
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+  } else {
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+    tv.tv_sec = m_sec;
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+    tv.tv_usec = -((-m_ns + 500) / 1000);
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+    if (tv.tv_usec <= -1000000) {
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+      --tv.tv_sec;
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+      tv.tv_usec += 1000000;
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+    }
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+  }
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+}
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+
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 /// fix internal time representation after calculation
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 void Time::fix()
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 {
src/linux/Time.h
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@@ -7,6 +7,7 @@
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 #define TIME_H
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 #include <stdint.h>
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+#include <sys/time.h>
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 #include <time.h>
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 namespace Blinker {
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@@ -66,6 +67,12 @@ public:
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    */
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   time_t toSec() const;
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+  /**
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+   * @brief convert to struct timeval
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+   * @param[out] tv struct timeval
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+   */
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+  void toTimeval(struct timeval &tv) const;
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+
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 public:
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   /// sleep for duration
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   void sleepFor() const;
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