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bee_version_compare: Rewrite compare_version_strings() #53

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merged 8 commits into from
Jul 8, 2022
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Commits on Jul 7, 2022

  1. bee_version_compare: Rewrite compare_version_strings()

    The current algorithm is complicated and broken.
    
    First, it removes common prefixes, so that, for example, '1.5.8' and
    '1.5.9' are compared numerically as 8 and 9.  After that, '0's are
    skipped, to that, for example, '1.5.09' can compare equal to '1.5.9'.
    
    In a next step, removed digits are restored, so that
    that '1.5.1134' and '1.5.1211' are compared as 1134 and 1211 and not
    as 34 and 11.
    
    However, the removal of '0's is done independently for both values, so
    that a different number of '0's might be removed, while the undo is done
    in sync, so that the same number of digits is 'restored'.
    
    As a result, '1.101' compares less that '1.11':
    
    a             b
    
    1.101         1.11  # original
    01            1     # after removal of common prefix
    1             1     # after removal of '0's
    01            11    # after restoration of digits
    
    Additionally, the code tries to sort digits after non-digit characters
    but failed to miss the case, when only the second string starts with a
    digit.
    
    Rewrite algorithm from scratch.
    
    The new algorithm advances through both strings comparing them at their
    beginning
    
      - if both strings start with a digit
         - compare numerically
         - if equal, skip over digits and loop
      - otherwise if the first character is different, compare character values
      - otherwise if both strings end, result is 0 (equal)
      - otherwise, advance to next character and loop
    
    We intentionally don't sort digits after non-digits, as the old code
    tried, because this makes more sense for the case when we have a hex
    string (e.g. from a git hash) as part of the version string.
    
    To make the code more readable, the character pointers are dereferenced
    multiple times and some conditionals are evaluated multiple times. We
    can trust the compiler to optimize this away.
    
    Comparing 'bee list --available' with the old and the new algorithm
    produces the following differences:
    
    firefox-9.0.1-0.x86_64          firefox-9.0.1-0.x86_64
    firefox-10.0.2-0.x86_64         firefox-10.0.2-0.x86_64
    firefox-102.0-0.x86_64       <
    firefox-11.0-0.x86_64           firefox-11.0-0.x86_64
    firefox-12.0-0.x86_64           firefox-12.0-0.x86_64
    
    firefox-94.0.1-0.x86_64         firefox-94.0.1-0.x86_64
    firefox-94.0.2-0.x86_64         firefox-94.0.2-0.x86_64
                                 >  firefox-102.0-0.x86_64
    firefox_current-4-0.x86_64      firefox_current-4-0.x86_64
    firefox_current-5-0.x86_64      firefox_current-5-0.x86_64
    
    java-1.7.0_13-0.x86_64          java-1.7.0_13-0.x86_64
    java-1.7.0_17-0.x86_64          java-1.7.0_17-0.x86_64
                                 >  java-1.8.0_11-0.x86_64
                                 >  java-1.8.0_45-0.x86_64
    java-1.8.0_101-0.x86_64         java-1.8.0_101-0.x86_64
    java-1.8.0_102-0.x86_64         java-1.8.0_102-0.x86_64
    java-1.8.0_102-1.x86_64         java-1.8.0_102-1.x86_64
    java-1.8.0_11-0.x86_64       <
    java-1.8.0_45-0.x86_64       <
    java-1.8.0_121-0.x86_64         java-1.8.0_121-0.x86_64
    java-1.8.0_131-0.x86_64         java-1.8.0_131-0.x86_64
    
    mxq-0.0_p106_8a0ad87-0.x86_64           mxq-0.0_p106_8a0ad87-0.x86_64
    mxq-0.0_p107_eaf8146-0.x86_64           mxq-0.0_p107_eaf8146-0.x86_64
    mxq-0.0_p108_f56522b-0.x86_64         <
    mxq-0.0_p108_0b7afc1-0.x86_64           mxq-0.0_p108_0b7afc1-0.x86_64
    mxq-0.0_p108_4e83c8d-0.x86_64           mxq-0.0_p108_4e83c8d-0.x86_64
    mxq-0.0_p109_ed52e7f-0.x86_64         | mxq-0.0_p108_f56522b-0.x86_64
    mxq-0.0_p109_621fea8-0.x86_64           mxq-0.0_p109_621fea8-0.x86_64
                                          > mxq-0.0_p109_ed52e7f-0.x86_64
    mxq-0.0_p110_baba367-0.x86_64           mxq-0.0_p110_baba367-0.x86_64
    mxq-0.0_p111_38cc7db-0.x86_64           mxq-0.0_p111_38cc7db-0.x86_64
    
    mxq-0.1.1_p1_4840161-0.x86_64           mxq-0.1.1_p1_4840161-0.x86_64
    mxq-0.1.2_p0_d21c6ae-0.x86_64           mxq-0.1.2_p0_d21c6ae-0.x86_64
    mxq-0.1.2_p1_efa8ec4-0.x86_64         <
    mxq-0.1.2_p1_9ccc12f-0.x86_64           mxq-0.1.2_p1_9ccc12f-0.x86_64
                                          > mxq-0.1.2_p1_efa8ec4-0.x86_64
    mxq-0.1.3_p0_0c3032c-0.x86_64           mxq-0.1.3_p0_0c3032c-0.x86_64
    mxq-0.1.4_p0_c936ba0-0.x86_64           mxq-0.1.4_p0_c936ba0-0.x86_64
    
    mxstartup-2.9_p1_0e23fa8-0.x86_64       mxstartup-2.9_p1_0e23fa8-0.x86_64
    mxstartup-2.9_p2_e915bc3-0.x86_64       mxstartup-2.9_p2_e915bc3-0.x86_64
    mxstartup-2.9_p3_d919716-0.x86_64     <
    mxstartup-2.9_p3_21347ab-0.x86_64       mxstartup-2.9_p3_21347ab-0.x86_64
                                          > mxstartup-2.9_p3_d919716-0.x86_64
    mxstartup-2.10_p0_d919716-0.x86_64      mxstartup-2.10_p0_d919716-0.x86_64
    mxstartup-2.11_p0_4ee8fed-0.x86_64      mxstartup-2.11_p0_4ee8fed-0.x86_64
    donald committed Jul 7, 2022
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Commits on Jul 8, 2022

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  2. Makefile: Add -O3

    donald committed Jul 8, 2022
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  5. tree: Add fall through annotations

    Gcc can warn on implicit fallthroughs. Mark them with a comment which is
    recognized by gcc.
    donald committed Jul 8, 2022
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  7. Makefile: Add -Wextra -Wno-override-init -Werror

    Enable -Wextra. Exclude -Wno-override-init for now, because bee_getopt.h
    relies on it. See [1] for similar issue in mxq.
    
    [1]: mariux64/mxq#131
    donald committed Jul 8, 2022
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