Based on (hunk for changelog removed)
From b62c902dd258125cac86cd2df21fc898035a43d3 Mon Sep 17 00:00:00 2001
From: Michael Pruett <michael@68k.org>
Date: Mon, 29 Aug 2016 23:08:26 -0500
Subject: [PATCH] Fix undefined behavior in sign conversion.


---
 ChangeLog                           | 5 +++++
 libaudiofile/modules/SimpleModule.h | 3 ++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/libaudiofile/modules/SimpleModule.h b/libaudiofile/modules/SimpleModule.h
index 03c6c69..bad85ad 100644
--- a/libaudiofile/modules/SimpleModule.h
+++ b/libaudiofile/modules/SimpleModule.h
@@ -123,7 +123,8 @@ struct signConverter
 	typedef typename IntTypes<Format>::UnsignedType UnsignedType;
 
 	static const int kScaleBits = (Format + 1) * CHAR_BIT - 1;
-	static const int kMinSignedValue = -1 << kScaleBits;
+	static const int kMaxSignedValue = (((1 << (kScaleBits - 1)) - 1) << 1) + 1;
+	static const int kMinSignedValue = -kMaxSignedValue - 1;
 
 	struct signedToUnsigned : public std::unary_function<SignedType, UnsignedType>
 	{
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