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diffcore-rename: simplify limit check

diffcore-rename had two different checks of the form

    if ((a < limit || b < limit) &&
        a * b <= limit * limit)

This can be simplified to

    if (st_mult(a, b) <= st_mult(limit, limit))

which makes it clearer how we are checking for overflow, and makes it
much easier to parse given the drop from 8 to 4 variable appearances.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Elijah Newren 2020-12-11 09:08:42 +00:00 committed by Junio C Hamano
parent 00b8cccdd8
commit ad8a1be529

View File

@ -447,12 +447,16 @@ static int too_many_rename_candidates(int num_destinations, int num_sources,
* growing larger than a "rename_limit" square matrix, ie:
*
* num_destinations * num_sources > rename_limit * rename_limit
*
* We use st_mult() to check overflow conditions; in the
* exceptional circumstance that size_t isn't large enough to hold
* the multiplication, the system won't be able to allocate enough
* memory for the matrix anyway.
*/
if (rename_limit <= 0)
rename_limit = 32767;
if ((num_destinations <= rename_limit || num_sources <= rename_limit) &&
((uint64_t)num_destinations * (uint64_t)num_sources
<= (uint64_t)rename_limit * (uint64_t)rename_limit))
if (st_mult(num_destinations, num_sources)
<= st_mult(rename_limit, rename_limit))
return 0;
options->needed_rename_limit =
@ -468,9 +472,8 @@ static int too_many_rename_candidates(int num_destinations, int num_sources,
continue;
limited_sources++;
}
if ((num_destinations <= rename_limit || limited_sources <= rename_limit) &&
((uint64_t)num_destinations * (uint64_t)limited_sources
<= (uint64_t)rename_limit * (uint64_t)rename_limit))
if (st_mult(num_destinations, limited_sources)
<= st_mult(rename_limit, rename_limit))
return 2;
return 1;
}