zstd/contrib/seekable_format
Yann Collet ededcfca57 fix confusion between unsigned <-> U32
as suggested in #1441.

generally U32 and unsigned are the same thing,
except when they are not ...

case : 32-bit compilation for MIPS (uint32_t == unsigned long)

A vast majority of transformation consists in transforming U32 into unsigned.
In rare cases, it's the other way around (typically for internal code, such as seeds).

Among a few issues this patches solves :
- some parameters were declared with type `unsigned` in *.h,
  but with type `U32` in their implementation *.c .
- some parameters have type unsigned*,
  but the caller user a pointer to U32 instead.

These fixes are useful.

However, the bulk of changes is about %u formating,
which requires unsigned type,
but generally receives U32 values instead,
often just for brevity (U32 is shorter than unsigned).
These changes are generally minor, or even annoying.

As a consequence, the amount of code changed is larger than I would expect for such a patch.

Testing is also a pain :
it requires manually modifying `mem.h`,
in order to lie about `U32`
and force it to be an `unsigned long` typically.
On a 64-bit system, this will break the equivalence unsigned == U32.
Unfortunately, it will also break a few static_assert(), controlling structure sizes.
So it also requires modifying `debug.h` to make `static_assert()` a noop.
And then reverting these changes.

So it's inconvenient, and as a consequence,
this property is currently not checked during CI tests.
Therefore, these problems can emerge again in the future.

I wonder if it is worth ensuring proper distinction of U32 != unsigned in CI tests.
It's another restriction for coding, adding more frustration during merge tests,
since most platforms don't need this distinction (hence contributor will not see it),
and while this can matter in theory, the number of platforms impacted seems minimal.

Thoughts ?
2018-12-21 18:09:41 -08:00
..
examples fixed multiple conversions 2018-12-13 14:02:22 -08:00
zstd_seekable.h fixed seekable_format type mismatch 2018-06-06 13:10:29 -07:00
zstd_seekable_compression_format.md s/chunk/frame/ 2017-04-12 11:15:50 -07:00
zstdseek_compress.c fix confusion between unsigned <-> U32 2018-12-21 18:09:41 -08:00
zstdseek_decompress.c fix confusion between unsigned <-> U32 2018-12-21 18:09:41 -08:00