From d102cbcda7f040d7491326a6a567ba7fa3773b07 Mon Sep 17 00:00:00 2001
From: Pavel Krajcevski <pavel@cs.unc.edu>
Date: Wed, 29 Aug 2012 14:43:37 -0400
Subject: [PATCH] Add threading support in core lib via boost libraries.

---
 Core/CMakeLists.txt      | 14 ++++++++++
 Core/src/TexComp.cpp     | 12 +++++++--
 Core/src/ThreadGroup.cpp | 58 ++++++++++++++++++++++++++++++++++++++++
 Core/src/ThreadGroup.h   | 53 ++++++++++++++++++++++++++++++++++++
 4 files changed, 135 insertions(+), 2 deletions(-)
 create mode 100644 Core/src/ThreadGroup.cpp
 create mode 100644 Core/src/ThreadGroup.h

diff --git a/Core/CMakeLists.txt b/Core/CMakeLists.txt
index 6af42b0..99e2d63 100644
--- a/Core/CMakeLists.txt
+++ b/Core/CMakeLists.txt
@@ -17,6 +17,16 @@ INCLUDE_DIRECTORIES( ${TexC_BINARY_DIR}/IO/include )
 
 INCLUDE_DIRECTORIES( ${TexC_SOURCE_DIR}/Core/include )
 
+FIND_PACKAGE( Boost COMPONENTS thread system ) 
+IF( Boost_FOUND )
+	INCLUDE_DIRECTORIES( ${Boost_INCLUDE_DIR} )
+
+	SET( SOURCES ${SOURCES} "src/ThreadGroup.cpp")
+	SET( HEADERS ${HEADERS} "src/ThreadGroup.h")
+
+	LINK_DIRECTORIES( ${Boost_LIBRARY_DIR} )
+ENDIF()
+
 ADD_LIBRARY( TexCompCore
 	${HEADERS}
 	${SOURCES}
@@ -24,3 +34,7 @@ ADD_LIBRARY( TexCompCore
 
 TARGET_LINK_LIBRARIES( TexCompCore TexCompIO )
 TARGET_LINK_LIBRARIES( TexCompCore BPTCEncoder )
+
+IF( Boost_FOUND )
+	TARGET_LINK_LIBRARIES( TexCompCore ${Boost_LIBRARIES} )
+ENDIF()
diff --git a/Core/src/TexComp.cpp b/Core/src/TexComp.cpp
index 99203f5..b0d8c09 100644
--- a/Core/src/TexComp.cpp
+++ b/Core/src/TexComp.cpp
@@ -1,5 +1,6 @@
 #include "BC7Compressor.h"
 #include "TexComp.h"
+#include "ThreadGroup.h"
 
 #include <stdlib.h>
 #include <stdio.h>
@@ -55,8 +56,15 @@ CompressedImage * CompressImage(
 
   CompressionFunc f = ChooseFuncFromSettings(settings);
   if(f) {
-    (*f)(img.GetPixels(), cmpData, img.GetWidth(), img.GetHeight());
-    outImg = new CompressedImage(img.GetWidth(), img.GetHeight(), settings.format, cmpData);
+    if(settings.iNumThreads > 1) {
+      ThreadGroup tgrp (settings.iNumThreads, img, f, cmpData);
+      tgrp.Start();
+      tgrp.Join();
+    }
+    else {
+      (*f)(img.GetPixels(), cmpData, img.GetWidth(), img.GetHeight());
+      outImg = new CompressedImage(img.GetWidth(), img.GetHeight(), settings.format, cmpData);
+    }
   }
   else {
     ReportError("Could not find adequate compression function for specified settings");
diff --git a/Core/src/ThreadGroup.cpp b/Core/src/ThreadGroup.cpp
new file mode 100644
index 0000000..af43cbf
--- /dev/null
+++ b/Core/src/ThreadGroup.cpp
@@ -0,0 +1,58 @@
+#include "ThreadGroup.h"
+
+#include <boost/thread/thread.hpp>
+#include <boost/thread/barrier.hpp>
+
+CmpThread::CmpThread() 
+  : m_Barrier(NULL)
+  , m_Width(0)
+  , m_Height(0)
+  , m_CmpFunc(NULL)
+  , m_OutBuf(NULL)
+  , m_InBuf(NULL)
+{ }
+
+void CmpThread::operator()() {
+  if(!m_Barrier || !m_CmpFunc || !m_OutBuf || !m_InBuf ) {
+    fprintf(stderr, "Incorrect thread initialization.\n");
+    return;
+  }
+
+  m_Barrier->wait();
+}
+
+
+ThreadGroup::ThreadGroup( int numThreads, const ImageFile &, CompressionFunc func, unsigned char *outBuf )
+  : m_Barrier(new boost::barrier(numThreads))
+  , m_NumThreads(numThreads)
+  , m_ActiveThreads(0)
+{ }
+
+ThreadGroup::~ThreadGroup() {
+  delete m_Barrier;
+}
+
+void ThreadGroup::Start() {
+
+  for(int i = 0; i < m_NumThreads; i++) {
+
+    if(m_ActiveThreads >= kMaxNumThreads)
+      break;
+
+    CmpThread &t = m_Threads[m_ActiveThreads];
+    m_ThreadHandles[m_ActiveThreads] = new boost::thread(t);
+
+    m_ActiveThreads++;
+  }
+
+}
+
+void ThreadGroup::Join() {
+
+  for(int i = 0; i < m_ActiveThreads; i++) {
+    m_ThreadHandles[i]->join();
+    delete m_ThreadHandles[i];
+  }
+
+  m_ActiveThreads = 0;
+}
diff --git a/Core/src/ThreadGroup.h b/Core/src/ThreadGroup.h
new file mode 100644
index 0000000..8a08d05
--- /dev/null
+++ b/Core/src/ThreadGroup.h
@@ -0,0 +1,53 @@
+#ifndef _THREAD_GROUP_H_
+#define _THREAD_GROUP_H_
+
+#include "TexComp.h"
+
+// forward declare
+namespace boost {
+  class barrier;
+  class thread;
+}
+
+struct CmpThread {
+  friend class ThreadGroup;  
+
+private:
+  boost::barrier *m_Barrier;
+
+  int m_Width;
+  int m_Height;
+
+  CompressionFunc m_CmpFunc;
+
+  unsigned char *m_OutBuf;
+  const unsigned char *m_InBuf;
+
+  CmpThread();
+
+public:
+  void operator ()();
+};
+
+
+class ThreadGroup {
+ public:
+  ThreadGroup( int numThreads, const ImageFile &, CompressionFunc func, unsigned char *outBuf );
+  ~ThreadGroup();
+
+  void Start();
+  void Join();
+
+ private:
+  boost::barrier *m_Barrier;
+
+  static const int kMaxNumThreads = 256;
+  const int m_NumThreads;
+
+  int m_ActiveThreads;
+
+  CmpThread m_Threads[kMaxNumThreads];
+  boost::thread *m_ThreadHandles[kMaxNumThreads];
+};
+
+#endif // _THREAD_GROUP_H_