pcm/PcmFormat: eliminate more duplicate code with templates

Refactor the conversion functions to classes and pass an instance to
the new function AllocateConvert().

1 files changed, 64 insertions, 0 deletions

diff --git a/src/pcm/FloatConvert.hxx b/src/pcm/FloatConvert.hxx
new file mode 100644
index 000000000..93e867159
--- /dev/null
+++ b/src/pcm/FloatConvert.hxx
@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) 2003-2014 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef MPD_PCM_FLOAT_CONVERT_HXX
+#define MPD_PCM_FLOAT_CONVERT_HXX
+
+#include "Traits.hxx"
+
+/**
+ * Convert from float to an integer sample format.
+ */
+template<SampleFormat F, class Traits=SampleTraits<F>>
+struct FloatToIntegerSampleConvert {
+	typedef SampleTraits<SampleFormat::FLOAT> SrcTraits;
+	typedef Traits DstTraits;
+
+	typedef typename SrcTraits::value_type SV;
+	typedef typename SrcTraits::long_type SL;
+	typedef typename DstTraits::value_type DV;
+
+	static constexpr SV factor = 1 << (DstTraits::BITS - 1);
+
+	gcc_const
+	static DV Convert(SV src) {
+		return PcmClamp<F, Traits>(SL(src * factor));
+	}
+};
+
+/**
+ * Convert from an integer sample format to float.
+ */
+template<SampleFormat F, class Traits=SampleTraits<F>>
+struct IntegerToFloatSampleConvert {
+	typedef SampleTraits<SampleFormat::FLOAT> DstTraits;
+	typedef Traits SrcTraits;
+
+	typedef typename SrcTraits::value_type SV;
+	typedef typename DstTraits::value_type DV;
+
+	static constexpr DV factor = 0.5 / (1 << (SrcTraits::BITS - 2));
+
+	gcc_const
+	static DV Convert(SV src) {
+		return DV(src) * factor;
+	}
+};
+
+#endif