1 files changed, 81 insertions, 0 deletions

diff --git a/src/itocondition.h b/src/itocondition.h
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--- /dev/null
+++ b/src/itocondition.h
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+#ifndef ITO_CONDITION_H
+#define ITO_CONDITION_H
+
+#include <pthread.h>
+
+#include "itomutex.h"
+
+namespace Bu
+{
+        /**
+         * Ito condition.  This is a fairly simple condition mechanism.  As you may
+         * notice this class inherits from the ItoMutex class, this is because all
+         * conditions must be within a locked block.  The standard usage of a condition
+         * is to pause one thread, perhaps indefinately, until another thread signals
+         * that it is alright to procede.
+         * <br>
+         * Standard usage for the thread that wants to wait is as follows:
+         * <pre>
+         * ItoCondition cond;
+         * ... // Perform setup and enter your run loop
+         * cond.lock();
+         * while( !isFinished() ) // Could be anything you're waiting for
+         *     cond.wait();
+         * ...  // Take care of what you have to.
+         * cond.unlock();
+         * </pre>
+         * The usage for the triggering thread is much simpler, when it needs to tell
+         * the others that it's time to grab some data it calls either signal or
+         * broadcast.  See both of those functions for the difference.
+         *@author Mike Buland
+         */
+        class ItoCondition : public ItoMutex
+        {
+        public:
+                /**
+                 * Create a condition.
+                 */
+                ItoCondition();
+
+                /**
+                 * Destroy a condition.
+                 */
+                ~ItoCondition();
+
+                /**
+                 * Wait forever, or until signalled.  This has to be called from within a
+                 * locked section, i.e. before calling this this object's lock function
+                 * should be called.
+                 */
+                int wait();
+
+                /**
+                 * Wait for a maximum of nSec seconds and nUSec micro-seconds or until
+                 * signalled.  This is a little more friendly function if you want to
+                 * perform other operations in the thrad loop that calls this function.
+                 * Like the other wait function, this must be inside a locked section.
+                 *@param nSec The seconds to wait.
+                 *@param nUSec the micro-seconds to wait.
+                 */
+                int wait( int nSec, int nUSec );
+
+                /**
+                 * Notify the next thread waiting on this condition that they can go ahead.
+                 * This only signals one thread, the next one in the condition queue, that
+                 * it is safe to procede with whatever operation was being waited on.
+                 */
+                int signal();
+
+                /**
+                 * Notify all threads waiting on this condition that they can go ahead now.
+                 * This function is slower than signal, but more effective in certain
+                 * situations where you may not know how many threads should be activated.
+                 */
+                int broadcast();
+
+        private:
+                pthread_cond_t cond;    /**< Internal condition reference. */
+        };
+}
+
+#endif