So given that there are apparently people on this mailing list, has anyone had
a look at this? I've not heard anything back at all.
Thanks.
From: [email protected]
To: [email protected]
Date: Wed, 28 Jan 2009 19:50:10 +0000
Subject: [Flac-dev] Missing dereference in Stream::set_metadata()?
Hello,
I seem to have hit a bug with adding meta data to a stream via the C++
interface. I am using FLAC 1.2.1. I've had a look through the email list
archive and can't spot anything similar.
The Stream::set_metadata(Prototype) function takes a double pointer which
implies that it is expecting an array of pointers to Prototype objects. For
example:
FLAC::Metadata::Prototype *table[2];
FLAC::Metadata::VorbisComment comment;
FLAC::Metadata::SeekTable seek;
table[0] = &seek;
table[1] = &comment;
bool bSuccess = encoder->set_metadata( table, 2 );
The assumption from the (very brief) API doxygen is that it will internally
convert from FLAC::Metadata::Prototype pointers to FLAC__StreamMetadata
pointers. Looking at the code, it does do the conversion but as a straight cast
which is therefore nothing more than an assignment. As the two objects are not
equivalent, this is a broken conversion. It results in an array of FLAC_SM
pointers that return gibberish when used and produces seg faults, infinite
memory consumption and other nasty effects!
The code needs to derefence the FLAC::M::P pointer before doing the cast in
order to make the compiler call the conversion operator on the object. That is,
it should read:
m[i] = const_cast< ::FLAC__StreamMetadata*>((const
::FLAC__StreamMetadata*)*metadata[i]);
If I make the above change then everything works quite happily and I can
produce FLAC files that are exact binary matches with those produced by the
flac command line tool.
Is this a genuine bug or am I missing something?
Thanks.
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