Re-implement the check for HAVE_POSIX_FADVISE.

It is unclear why this was removed.

If this needs to be removed again, either do so through the config file or the definition checks.

StepmaniaCore.cmake

@@ -113,6 +113,7 @@ check_symbol_exists(M_PI math.h HAVE_M_PI)
 check_symbol_exists(size_t stddef.h HAVE_SIZE_T_STDDEF)
 check_symbol_exists(size_t stdlib.h HAVE_SIZE_T_STDLIB)
 check_symbol_exists(size_t stdio.h HAVE_SIZE_T_STDIO)
+check_symbol_exists(posix_fadvise fcntl.h HAVE_POSIX_FADVISE)
 
 # Checks to make it easier to work with 32-bit/64-bit builds if required.
 include(CheckTypeSize)

src/RageFileManager_ReadAhead.cpp

@@ -79,14 +79,13 @@ private:
 	
 	void WorkerMain()
 	{
-		RString sBuffer;
 		int iFDCopy = dup( m_iFD );
 		if( iFDCopy != -1 )
 		{
-			char *pBuf = sBuffer.GetBuffer( m_iBytes );
+			char [] buf = new char[m_iBytes];
 			lseek( iFDCopy, m_iFrom, SEEK_SET );
-			read( iFDCopy, pBuf, m_iBytes );
-			sBuffer.ReleaseBuffer( m_iBytes );
+			read( iFDCopy, buf, m_iBytes );
+			delete [] buf;
 
 			close( iFDCopy );
 			LOG->Trace("read");
@@ -154,9 +153,9 @@ void RageFileManagerReadAhead::DiscardCache( RageFileBasic *pFile, int iRelative
 #endif
 #endif
 
-#if defined(HAVE_POSIX_FADVISE)
 void RageFileManagerReadAhead::CacheHintStreaming( RageFileBasic *pFile )
 {
+#if defined(HAVE_POSIX_FADVISE)
 	/* This guesses at the actual size of the file on disk, which may be smaller if this file is compressed.
 	 * Since this is usually used on music and video files, it generally shouldn't be. */
 	int iFD = pFile->GetFD();
@@ -166,10 +165,8 @@ void RageFileManagerReadAhead::CacheHintStreaming( RageFileBasic *pFile )
 	int iFrom = lseek( iFD, 0, SEEK_CUR );
 	int iBytes = pFile->GetFileSize() - iPos;
 	posix_fadvise( iFD, iFrom, iBytes, POSIX_FADV_SEQUENTIAL );
-}
-#else
-void RageFileManagerReadAhead::CacheHintStreaming( RageFileBasic *pFile ) { }
 #endif
+}
 
 
 /*

src/config.in.hpp

@@ -81,6 +81,9 @@
 /* Defined to 1 if the underlying system provides the M_PI constant. */
 #cmakedefine HAVE_M_PI 1
 
+/* Defined to 1 if the underlying system provides the posix_fadvise function. */
+#cmakedefine HAVE_POSIX_FADVISE 1
+
 /* Provide a fallback if intptr_t is not defined. */
 #cmakedefine HAVE_SIZEOF_INTPTR_T 1
 #if !defined(HAVE_SIZEOF_INTPTR_T)