* patterns/tiff: show TIFF tag name/number in DirectoryEntry array
Don't require unfolding the array entry to see what tag it contains.
* patterns/tiff: show IFD number in IFD list
* patterns/tiff: add JPEGTables tag; correct name of ICC Profile tag
* patterns/tiff: add TIFFRational type
Rationals, uniquely, are primitives with two fields. Add a struct to
represent this, rather than inlining them.
* patterns/tiff: use correct types for fields smaller than 4 bytes
Small fields are always left-aligned in the 4-byte Value Offset. On
little-endian TIFFs we currently cheat this by declaring a 32-bit value
and letting little-endianness handle the semantics. However, this adds
some extra conditionals, and misrepresents the resulting field as 32 bits.
Drop the cheat.
* patterns/tiff: add ValueOffset abstraction
We were using the field type to make assumptions about whether the Value
Offset is a Value or an Offset, which is incorrect. If the Count
multiplied by the field size is larger than 4, the field is an Offset;
otherwise it's a Value.
Add display sugar for single-element arrays to avoid extra nesting.
* patterns/tiff: drop dead code
get_ifds_offsets() and BIG/LITTLE aren't used at all. get_total_IFDs()
is only used for declaring the length of TIFFFile.IFDs, and isn't needed
because IFDs are structured as a linked list.
* patterns/tiff: drop set_endian()
The call in TIFFFile is redundant. Drop both calls and open-code the
check at the top level, before executing any code. The BigTIFF check
will eventually be added alongside this one.
Fail if we don't recognize the magic number.
* patterns/tiff: minor cleanups
* patterns/tiff: drop strip offset/byte count arrays from struct IFD
They're redundant with the fields in the DirectoryEntry array. Also
they're buggy: they assume the field Value Offsets are always offsets,
which isn't true for single-strip IFDs, and they ignore a partial last
strip in multiple-strip IFDs.
* patterns/tiff: rewrite strip array generation
We're making extra work for ourselves by avoiding the type system. Also,
by calculating the number of strips we expect rather than the number of
strips we actually have, we're miscounting and omitting any partial last
strip.
Instead, read the strip offsets and byte counts directly from the
IFDEntry array.
* patterns/tiff: add ImageData array for tiled IFDs
* patterns/tiff: increase variable widths for BigTIFF
Use 64-bit temporary variables for values that can be 64 bits in BigTIFF.
* patterns/tiff: support BigTIFF
* tests/patterns/test_data: add more TIFF tests
* Create tiff.hexpat
* Update README.md
Update readme to include tiff hexpat
* added file to test the pattern
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Co-authored-by: joelalves <joel.17.alves@gmail.com>
