Re: [PATCH v7 0/5] Update LZ4 compressor module
From: Sven Schmidt
Date: Thu Feb 09 2017 - 06:08:42 EST
Hey Eric,
On Wed, Feb 08, 2017 at 09:24:25PM -0800, Eric Biggers wrote:
> Also I noticed another bug, this time in LZ4_count():
>
> > #if defined(CONFIG_64BIT)
> > #define LZ4_ARCH64 1
> > #else
> > #define LZ4_ARCH64 0
> > #endif
> ...
> > #ifdef LZ4_ARCH64
> > if ((pIn < (pInLimit-3))
> > && (LZ4_read32(pMatch) == LZ4_read32(pIn))) {
> > pIn += 4; pMatch += 4;
> > }
> > #endif
>
> Because of how LZ4_ARCH64 is defined, it needs to be '#if LZ4_ARCH64'.
>
> But I also think the way upstream LZ4 does 64-bit detection could have just been
> left as-is; it has a function which gets inlined:
>
> static unsigned LZ4_64bits(void) { return sizeof(void*)==8; }
>
> Eric
does this apply for LZ4_isLittleEndian() as well? As a reminder:
static unsigned LZ4_isLittleEndian(void)
{
/* don't use static : performance detrimental */
const union { U32 u; BYTE c[4]; } one = { 1 };
return one.c[0];
}
It is surely easier to read and understand using these functions in favor of the macros.
Thanks,
Sven