Add a script to update qm-dsp library

tools/update_qm-dsp.sh

@@ -0,0 +1,75 @@
+#!/bin/sh
+
+if ! test -f wscript || ! test -d gtk2_ardour || ! test -d libs/qm-dsp/;then
+	echo "This script needs to run from ardour's top-level src tree"
+	exit 1
+fi
+
+if test -z "`which rsync`" -o -z "`which git`"; then
+	echo "this script needs rsync and git"
+	exit 1
+fi
+
+ASRC=`pwd`
+set -e
+
+cd libs/qm-dsp
+QMFILES=`find . -type f | grep -v MSVCqm-dsp | grep -v wscript`
+
+TMP=`mktemp -d`
+test -d "$TMP"
+echo $TMP
+trap "rm -rf $TMP" EXIT
+
+cd $TMP
+git clone git://github.com/c4dm/qm-dsp.git qm-dsp
+cd qm-dsp
+git describe --tags > "$ASRC/libs/qm-dsp/gitrev.txt"
+QMDSP="$TMP/qm-dsp"
+
+cd "$ASRC/libs/qm-dsp"
+find base dsp ext maths -type f -exec rsync -c --progress "$QMDSP/{}" "{}" \;
+
+
+## this applies to qm-vamp-plugins-v1.7.1-20-g4d15479
+## (see also Ardour 5.8-250-gc0c24aff7)
+patch -p3 << EOF
+diff --git a/libs/qm-dsp/dsp/signalconditioning/FiltFilt.cpp b/libs/qm-dsp/dsp/signalconditioning/FiltFilt.cpp
+index 714d5755d..c88641de7 100644
+--- a/libs/qm-dsp/dsp/signalconditioning/FiltFilt.cpp
++++ b/libs/qm-dsp/dsp/signalconditioning/FiltFilt.cpp
+@@ -35,6 +35,13 @@ void FiltFilt::process(double *src, double *dst, unsigned int length)
+ 
+     if (length == 0) return;
+ 
++    if (length < 2) {
++	for( i = 0; i < length; i++ ) {
++	    dst[i] = src [i];
++	}
++	return;
++    }
++
+     unsigned int nFilt = m_ord + 1;
+     unsigned int nFact = 3 * ( nFilt - 1);
+     unsigned int nExt	= length + 2 * nFact;
+@@ -58,11 +65,16 @@ void FiltFilt::process(double *src, double *dst, unsigned int length)
+ 	filtScratchIn[ index++ ] = sample0 - src[ i ];
+     }
+     index = 0;
+-    for( i = 0; i < nFact; i++ )
++    for( i = 0; i < nFact && i + 2 < length; i++ )
+     {
+ 	filtScratchIn[ (nExt - nFact) + index++ ] = sampleN - src[ (length - 2) - i ];
+     }
+ 
++    for(; i < nFact; i++ )
++    {
++	filtScratchIn[ (nExt - nFact) + index++ ] = 0;
++    }
++
+     index = 0;
+     for( i = 0; i < length; i++ )
+     {
+EOF
+
+git add gitrev.txt base dsp ext maths