In C, qualifiers for arrays are broken:
const VLC_TYPE (*foo)[2] is a pointer to an array of two const VLC_TYPE
elements and unfortunately this is not compatible with a pointer
to a const array of two VLC_TYPE, because the latter does not exist
as array types are never qualified (the qualifier applies to the base
type instead). This is the reason why get_vlc2() doesn't accept
a const VLC table despite not modifying the table at all, as
there is no automatic conversion from VLC_TYPE (*)[2] to
const VLC_TYPE (*)[2].
Fix this by using a structure VLCElem for the VLC table.
This also has the advantage of making it clear which
element is which.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
After permuting the codes, symbols and lengths tables used to initialize
the VLCs so that the codes are ordered from left to right in the Huffman
tree, the codes become redundant as they can be easily computed from the
lengths at runtime (or at compile time with --enable-hardcoded-tables);
in this case one has to use explicit symbol tables, but all the symbols
used here fit into an uint8_t, whereas some codes needed uint16_t.
Furthermore, the codes had holes because the range of the symbols was not
contiguous; these have also been removed.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Also adds a lot of infrastructure necessary for it.
Some of it is a bit ugly though.
Increases binary size for hardcoded tables by about 12 kB,
which is about 15 kB from qdm2_table minus data and code
saved that was only used for creating it.
Signed-off-by: Reimar Döffinger <Reimar.Doeffinger@gmx.de>
This prevents out of array reads. An alternative solution would be
to check the index but this would require several checks in the
inner loops
Yet another alternative would be to change the index reset logic
but this likely would introduce a difference to the binary decoder
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This code relies on the result wrapping as for unsigned
values, and the sign is not used. Thus an unsigned type
is proper here.
Signed-off-by: Mans Rullgard <mans@mansr.com>
Andreas Rheinhardt
Andreas Rheinhardt
Reimar Döffinger
Michael Niedermayer
Mans Rullgard
Diego Biurrun