From e1b949e31871691586ef0ca93b7a3f5cbaac7f92 Mon Sep 17 00:00:00 2001
From: Volker Fischer <corrados@users.noreply.github.com>
Date: Tue, 2 Mar 2010 18:22:55 +0000
Subject: [PATCH] fix for m-audio ASIO driver

---
 ChangeLog         |   2 +
 windows/sound.cpp | 102 ++++++++++++++++++++++++++++------------------
 2 files changed, 64 insertions(+), 40 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index a9ba2fb9..7b5058e1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -7,6 +7,8 @@
 
 - improvement of network buffer (jitter buffer) in case of small buffer sizes
 
+- bug fix for M-Audio Delta ASIO driver
+
 
 3.0.3
 
diff --git a/windows/sound.cpp b/windows/sound.cpp
index 84127674..101e7f8e 100755
--- a/windows/sound.cpp
+++ b/windows/sound.cpp
@@ -337,49 +337,71 @@ int CSound::GetActualBufferSize ( const int iDesiredBufferSizeMono )
             }
             else
             {
-                // General case ------------------------------------------------
-                // initialization
-                int  iTrialBufSize     = HWBufferInfo.lMinSize;
-                int  iLastTrialBufSize = HWBufferInfo.lMinSize;
-                bool bSizeFound        = false;
-
-                // test loop
-                while ( ( iTrialBufSize <= HWBufferInfo.lMaxSize ) && ( !bSizeFound ) )
+                if ( HWBufferInfo.lGranularity <= 0 )
                 {
-                    if ( iTrialBufSize >= iDesiredBufferSizeMono )
-                    {
-                        // test which buffer size fits better: the old one or the
-                        // current one
-                        if ( ( iTrialBufSize - iDesiredBufferSizeMono ) >
-                             ( iDesiredBufferSizeMono - iLastTrialBufSize ) )
-                        {
-                            iTrialBufSize = iLastTrialBufSize;
-                        }
-
-                        // exit while loop
-                        bSizeFound = true;
-                    }
-
-                    if ( !bSizeFound )
-                    {
-                        // store old trial buffer size
-                        iLastTrialBufSize = iTrialBufSize;
-
-                        // increment trial buffer size (check for special case first)
-                        if ( HWBufferInfo.lGranularity == -1 )
-                        {
-                            // special case: buffer sizes are a power of 2
-                            iTrialBufSize *= 2;
-                        }
-                        else
-                        {
-                            iTrialBufSize += HWBufferInfo.lGranularity;
-                        }
-                    }
+                    // Special case (seen for EMU audio cards): granularity is
+                    // zero or less than zero.
+                    // There is no definition of this case in the ASIO SDK
+                    // document. We assume here that all buffer sizes in between
+                    // minimum and maximum buffer sizes are allowed.
+                    iActualBufferSizeMono = iDesiredBufferSizeMono;
                 }
+                else
+                {
+                    // General case --------------------------------------------
+                    // initialization
+                    int  iTrialBufSize     = HWBufferInfo.lMinSize;
+                    int  iLastTrialBufSize = HWBufferInfo.lMinSize;
+                    bool bSizeFound        = false;
 
-                // set ASIO buffer size
-                iActualBufferSizeMono = iTrialBufSize;
+                    // test loop
+                    while ( ( iTrialBufSize <= HWBufferInfo.lMaxSize ) && ( !bSizeFound ) )
+                    {
+                        if ( iTrialBufSize >= iDesiredBufferSizeMono )
+                        {
+                            // test which buffer size fits better: the old one or the
+                            // current one
+                            if ( ( iTrialBufSize - iDesiredBufferSizeMono ) >
+                                 ( iDesiredBufferSizeMono - iLastTrialBufSize ) )
+                            {
+                                iTrialBufSize = iLastTrialBufSize;
+                            }
+
+                            // exit while loop
+                            bSizeFound = true;
+                        }
+
+                        if ( !bSizeFound )
+                        {
+                            // store old trial buffer size
+                            iLastTrialBufSize = iTrialBufSize;
+
+                            // increment trial buffer size (check for special
+                            // case first)
+                            if ( HWBufferInfo.lGranularity == -1 )
+                            {
+                                // special case: buffer sizes are a power of 2
+                                iTrialBufSize *= 2;
+                            }
+                            else
+                            {
+                                iTrialBufSize += HWBufferInfo.lGranularity;
+                            }
+                        }
+                    }
+
+                    // clip trial buffer size (it may happen in the while
+                    // routine that "iTrialBufSize" is larger than "lMaxSize" in
+                    // case "lMaxSize - lMinSize" is not divisible by the
+                    // granularity)
+                    if ( iTrialBufSize > HWBufferInfo.lMaxSize )
+                    {
+                        iTrialBufSize = HWBufferInfo.lMaxSize;
+                    }
+
+                    // set ASIO buffer size
+                    iActualBufferSizeMono = iTrialBufSize;
+                }
             }
         }
     }