At a few places in the code the switch/case ond flags are tested against
64-bit constants without explicitly being marked as long long. Some
32-bit compilers complain that the constant is too large for a long, and
other likely always use long long there. Better fix that as it's uncertain
what others which do not complain do. It may be backported to avoid doubts
on uncommon platforms if needed, as it touches very few areas.
mul32hi() multiples a constant a with a variable b from 0 to 0xffffffff
and shifts the result by 32 bits. It's visible that it's always impossible
to reach the constant a this way because the product always misses exactly
one unit of a to be preserved. And this cannot be corrected by the caller
either as adding one to the output will only shift the output range, and
it's not possible to pass 2^32 on the ratio <b>. The right approach is to
add "a" after the multiplication so that the input range is always
preserved for all ratio values from 0 to 0xffffffff:
(a=0x00000000 * b=0x00000000 + a=0x00000000) >> 32 = 0x00000000
(a=0x00000000 * b=0x00000001 + a=0x00000000) >> 32 = 0x00000000
(a=0x00000000 * b=0xffffffff + a=0x00000000) >> 32 = 0x00000000
(a=0x00000001 * b=0x00000000 + a=0x00000001) >> 32 = 0x00000000
(a=0x00000001 * b=0x00000001 + a=0x00000001) >> 32 = 0x00000000
(a=0x00000001 * b=0xffffffff + a=0x00000001) >> 32 = 0x00000001
(a=0xffffffff * b=0x00000000 + a=0xffffffff) >> 32 = 0x00000000
(a=0xffffffff * b=0x00000001 + a=0xffffffff) >> 32 = 0x00000001
(a=0xffffffff * b=0xffffffff + a=0xffffffff) >> 32 = 0xffffffff
This is only used in freq_ctr calculations and the slightly lower value
is unlikely to have ever been noticed by anyone. This may be backported
though it is not important.
There are quite a number of integer manipulation functions defined in
standard.h, which is one of the reasons why standard.h is included from
many places and participates to the dependencies loop.
Let's just have a new file, intops.h to place all these operations.
These are a few bitops, 32/64 bit mul/div/rotate, integer parsing and
encoding (including varints), the full avalanche hash function, and
the my_htonll/my_ntohll functions.
For now no new C file was created for these yet.
