From f6b2899dd2f2b7985da0cf3734a7276ea54e23a2 Mon Sep 17 00:00:00 2001
From: Max Kellermann <max@duempel.org>
Date: Sat, 25 Oct 2014 20:42:50 +0200
Subject: [PATCH] decoder/faad: remove workaround for ancient libfaad2 ABI bug

Many years ago, FAAD had a serious ABI bug: the NeAACDecInit()
prototype in its header declared the "samplerate" parameter to be
"unsigned long *", but internally, the function assumed it was
"uint32_t *" instead.  On 32 bit machines, that was no difference, but
on 64 bit, this left one portion of the return value uninitialized;
and worse, on big-endian, the wrong word was filled.  This bug had to
be worked around in MPD (commit 9c4e97a6).

A few months later, the bug was fixed in the FAAD CVS in commit 1.117
on file libfaad/decoder.c; the commit message was:

 "Use public headers internally to prevent duplicate declarations"

The commit message was too brief at best; the problem was not
duplicate declarations, but a prototype mismatch.  No mention of the
bug fix in the ChangeLog.

The MPD project never learned about this bug fix, and so MPD would
always pass a "uin32_t *" dressed up as a "unsigned long *".  Nearly 6
years later, it's about time to fix this second ABI problem.  Let's
kill the workaround!
---
 NEWS                              |  1 +
 m4/faad.m4                        | 31 +------------------------------
 src/decoder/FaadDecoderPlugin.cxx | 12 ++----------
 3 files changed, 4 insertions(+), 40 deletions(-)

diff --git a/NEWS b/NEWS
index 0706e447c..f27bd8c4f 100644
--- a/NEWS
+++ b/NEWS
@@ -1,5 +1,6 @@
 ver 0.18.17 (not yet released)
 * decoder
+  - faad: remove workaround for ancient libfaad2 ABI bug
   - ffmpeg: recognize MIME type audio/aacp
 
 ver 0.18.16 (2014/09/26)
diff --git a/m4/faad.m4 b/m4/faad.m4
index 5ca520e79..9dcb1ccab 100644
--- a/m4/faad.m4
+++ b/m4/faad.m4
@@ -62,36 +62,7 @@ int main() {
 	CPPFLAGS=$oldcppflags
 fi
 
-if test x$enable_aac = xyes; then
-	oldcflags=$CFLAGS
-	oldlibs=$LIBS
-	oldcppflags=$CPPFLAGS
-	CFLAGS="$CFLAGS $FAAD_CFLAGS -Werror"
-	LIBS="$LIBS $FAAD_LIBS"
-	CPPFLAGS=$CFLAGS
-
-	AC_MSG_CHECKING(for broken libfaad headers)
-	AC_COMPILE_IFELSE([AC_LANG_SOURCE([
-#include <faad.h>
-#include <stddef.h>
-#include <stdint.h>
-
-int main() {
-	unsigned char channels;
-	uint32_t sample_rate;
-
-	NeAACDecInit2(NULL, NULL, 0, &sample_rate, &channels);
-	return 0;
-}
-	])],
-		[AC_MSG_RESULT(correct)],
-		[AC_MSG_RESULT(broken);
-		AC_DEFINE(HAVE_FAAD_LONG, 1, [Define if faad.h uses the broken "unsigned long" pointers])])
-
-	CFLAGS=$oldcflags
-	LIBS=$oldlibs
-	CPPFLAGS=$oldcppflags
-else
+if test x$enable_aac = xno; then
 	FAAD_LIBS=""
 	FAAD_CFLAGS=""
 fi
diff --git a/src/decoder/FaadDecoderPlugin.cxx b/src/decoder/FaadDecoderPlugin.cxx
index b446ac5be..ae1181b4c 100644
--- a/src/decoder/FaadDecoderPlugin.cxx
+++ b/src/decoder/FaadDecoderPlugin.cxx
@@ -277,20 +277,12 @@ faad_decoder_init(NeAACDecHandle decoder, DecoderBuffer *buffer,
 	}
 
 	uint8_t channels;
-	uint32_t sample_rate;
-#ifdef HAVE_FAAD_LONG
-	/* neaacdec.h declares all arguments as "unsigned long", but
-	   internally expects uint32_t pointers.  To avoid gcc
-	   warnings, use this workaround. */
-	unsigned long *sample_rate_p = (unsigned long *)(void *)&sample_rate;
-#else
-	uint32_t *sample_rate_p = &sample_rate;
-#endif
+	unsigned long sample_rate;
 	long nbytes = NeAACDecInit(decoder,
 				   /* deconst hack, libfaad requires this */
 				   const_cast<unsigned char *>(data),
 				   length,
-				   sample_rate_p, &channels);
+				   &sample_rate, &channels);
 	if (nbytes < 0) {
 		error.Set(faad_decoder_domain, "Not an AAC stream");
 		return false;