Hugo Beauzée-Luyssen authored 3 years ago and Steve Lhomme committed 2 years ago

So we can ensure we are not reading out of bounds

Co-authored-by: Steve Lhomme <robux4@ycbcr.xyz>

Hugo Beauzée-Luyssen authored 3 years ago and Steve Lhomme committed 2 years ago

refs #16

Either it really should be zero and it's checked on reading via SkipZeroBuf().
Either the value is unknown and we just skip it via SkipBuf().

The field values are not actually set, so should not be used by anyone.
We keep the for reference of the size and structures they correspond to.

The PTT search table contains the TTU offset for each SRPT and then all the
PGCN/PGN values. Each block of PGCN/PGN starts at each TTU offset in the read
buffer.

Not all C compilers support Variable Length Array.

This will avoid potential typos and make refactoring easier.

We should not rely on the host compiler having a certain type of packing. Clang for Windows
doesn't support the GCC struct packing. We should never read directly into structures.

The structures are already read bit by bits.

The compiler using the library may not support the proper packing
(CLang for Windows doesn't support the GCC packing).

For now only for the bits by bits reading.

This is the size that is supposed to match the low level format, not the
structure size.

The structures on the other hand should be allocated with their own size.

Close #8

This was authorized by Eric Smith, original author of VOBDUMP, by email
on May 15, 2022

Steve Lhomme authored 3 years ago and Jean-Baptiste Kempf committed 2 years ago

According to [1] these 16 bits represent the "end address relative to command table".
This corresponds to the last_byte check in other places.

[1] http://dvd.sourceforge.net/dvdinfo/pgc.html#cmd

Steve Lhomme authored 3 years ago and Jean-Baptiste Kempf committed 3 years ago

It may not be in the end of the buffer anymore.

The byte value used was always equivalent to
> state->start[state->byte_position] << state->bit_position

Also constify the read buffer.

Steve Lhomme authored 3 years ago and Jean-Baptiste Kempf committed 3 years ago

The comments say it exists in the wild.

calloc() may or may not return NULL in that case. Just use NULL but assume it's
not an error.

to compute a canonical path