cvs commit: src/lib/libc/uuid uuid_compare.c

Xin LI delphij at
Thu Aug 3 03:34:37 UTC 2006

delphij     2006-08-03 03:34:36 UTC

  FreeBSD src repository

  Modified files:
    lib/libc/uuid        uuid_compare.c 
  In DCE 1.1, the time_low value is defined as an unsigned 32-bit
  integer.  Presently, our implementation employs an approach that
  converts the value to int64_t, then back to int, unfortunately,
  this approach can be problematic when the the difference between
  the two time_low is larger than 0x7fffffff, as the value is then
  truncated to int.
  To quote the test case from the original PR, the following is
  true with the current implementation:
  865e1a56-b9d9-11d9-ba27-0003476f2e88 < 062ac45c-b9d9-11d9-ba27-0003476f2e88
  However, according to the DCE specification, the expected result
  should be:
  865e1a56-b9d9-11d9-ba27-0003476f2e88 > 062ac45c-b9d9-11d9-ba27-0003476f2e88
  This commit adds a new intermediate variable which uses int64_t
  to store the result of subtraction between the two time_low values,
  which would not introduce different semantic of the MSB found in
  time_low value.
  PR:             83107
  Submitted by:   Steve Sears <sjs at acm dot org>
  MFC After:      1 month
  Revision  Changes    Path
  1.5       +15 -5     src/lib/libc/uuid/uuid_compare.c

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