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0d098211b7
Previously, ChunkID's from_big_endian_number() and
as_big_endian_number() weren't inverses of each other.
ChunkID::from_big_endian_number() used to take an u32 that contained
`('f' << 24) | ('t' << 16) | ('y' << 8) | 'p'`, that is
'f', 't', 'y', 'p' in memory on big-endian and 'p', 'y', 't', 'f'
on little-endian, and return a ChunkID for 'f', 't', 'y', 'p'.
ChunkID::as_big_endian_number() used to return an u32 that for a
ChunkID storing 'f', 't', 'y', 'p' was always 'f', 't', 'y', 'p'
in memory on both little-endian and big-endian, that is it stored
`('f' << 24) | ('t' << 16) | ('y' << 8) | 'p'` on big-endian and
`('p' << 24) | ('y' << 16) | ('t' << 8) | 'f'` on little-endian.
`ChunkID::from_big_endian_number(0x11223344).as_big_endian_number()`
returned 0x44332211.
This change makes the two methods self-consistent: they now take
and return a u32 that always has the first ChunkID part in the
highest bits of the u32 (`'f' << 24`), and so on. That also means
they return a u32 that in-memory looks differently on big-endian
and little-endian. Since that's normal for numbers, this also
renames the two methods to just `from_number()` and `to_number()`.
With the semantics cleared up, change the one use in ISOBMFF to read a
BigEndian for chunk headers and brand codes. This has the effect of
tags now being printed in the right order.
Before:
```sh
% Build/lagom/bin/isobmff ~/Downloads/sample1.jp2
Unknown Box (' Pj')
[ 4 bytes ]
('pytf') (version = 0, flags = 0x0)
- major_brand = ' 2pj'
- minor_version = 0
- compatible_brands = { ' 2pj' }
Unknown Box ('h2pj')
[ 37 bytes ]
Unknown Box ('fniu')
[ 92 bytes ]
Unknown Box (' lmx')
[ 2736 bytes ]
Unknown Box ('c2pj')
[ 667336 bytes ]
```
After:
```sh
% Build/lagom/bin/isobmff ~/Downloads/sample1.jp2
hmm 0x11223344 0x11223344
Unknown Box ('jP ')
[ 4 bytes ]
('ftyp' ) (version = 0, flags = 0x0)
- major_brand = 'jp2 '
- minor_version = 0
- compatible_brands = { 'jp2 ' }
Unknown Box ('jp2h')
[ 37 bytes ]
Unknown Box ('uinf')
[ 92 bytes ]
Unknown Box ('xml ')
[ 2736 bytes ]
Unknown Box ('jp2c')
[ 667336 bytes ]
```
|
||
|---|---|---|
| .. | ||
| ChunkID.h | ||
| CMakeLists.txt | ||
| Decoding.cpp | ||
| Details.cpp | ||
| Details.h | ||
| IFF.h | ||
| RIFF.h | ||