Initial Comit

common/mmap.cpp

@@ -0,0 +1,74 @@
+#include <common/mmap.hpp>
+#include <common/except.hpp>
+
+bool MemoryMappedFile::open(const String& pathFileName,CreationFlags creationFlags)
+{
+  if(isOkay())
+  {
+    close();
+  }
+  mFD=::open(pathFileName,getFileAccessFromFlags(creationFlags));
+  mCreationFlags= creationFlags;
+  if(!isOkay())return false;
+  struct stat sb;
+  if(-1==::fstat(mFD,&sb))
+  {
+    close();
+    return false;
+  }
+  mFileLength = sb.st_size;
+  if(!createMemoryMap())
+  {
+      close();
+      return false;
+  }
+  return true;
+}
+
+bool MemoryMappedFile::createMemoryMap(void)
+{
+  void *pAddress = ::mmap(NULL,mFileLength,getMemoryMapAccessFromFlags(mCreationFlags),mCreationFlags == CreationFlags::ReadOnly?MAP_PRIVATE:MAP_SHARED,mFD,0);
+  if(MAP_FAILED == pAddress)
+  {
+    return false;
+  }
+  mlpMappedDataBase = (char *)pAddress;
+  mIndex=0;
+  return true;
+}
+
+void MemoryMappedFile::close()
+{
+  if(!isOkay())return;
+  ::munmap((void*)mlpMappedDataBase, mFileLength);
+  ::close(mFD);
+  mFD=-1;
+  mFileLength=-1;
+}
+
+int MemoryMappedFile::getFileAccessFromFlags(CreationFlags creationFlags)const
+{
+  switch(creationFlags)
+  {
+    case ReadOnly :
+      return O_RDONLY | S_IRUSR ;
+    case ReadWrite :
+      return O_RDWR | O_CREAT, S_IRUSR | S_IWUSR;
+    default :
+      throw new Exception("Undefined creation flag");
+  }
+}
+
+int MemoryMappedFile::getMemoryMapAccessFromFlags(CreationFlags creationFlags)const
+{
+    switch(creationFlags)
+  {
+    case ReadOnly :
+      return PROT_READ;
+    case ReadWrite :
+      return PROT_READ | PROT_WRITE;
+    default :
+      throw new Exception("Undefined creation flag");
+  }
+}
+