lkml.org 
[lkml]   [2006]   [Dec]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    Subjectstrncpy optimalisation? (lib/string.c)
    Hi,

    In lib/string.c we have:

    char *strncpy(char *dest, const char *src, size_t count)
    {
    char *tmp = dest;

    while (count) {
    if ((*tmp = *src) != 0)
    src++;
    tmp++;
    count--;
    }
    return dest;
    }

    now I wonder isn't this ineffecient when strlen(src) < count? It would
    then, if I'm correct, iterate count-strlen(src) times doing useless
    increment/decrement. And since there are aprox. 580 instances in the
    2.6.18.2 source, maybe some efficency can be won here.
    Wouldn't it be better to do:
    if ((*tmp = *src) == 0x00)
    break;

    So that would be:
    --- lib/string.c 2006-11-04 02:33:58.000000000 +0100
    +++ string-new.c 2006-12-10 21:50:05.000000000 +0100
    @@ -97,8 +97,8 @@
    char *tmp = dest;

    while (count) {
    - if ((*tmp = *src) != 0)
    - src++;
    + if ((*tmp = *src) == 0x00)
    + break;
    tmp++;
    count--;
    }

    Folkert van Heusden

    --
    www.vanheusden.com/multitail - win een vlaai van multivlaai! zorg
    ervoor dat multitail opgenomen wordt in Fedora Core, AIX, Solaris of
    HP/UX en win een vlaai naar keuze
    ----------------------------------------------------------------------
    Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/
    \
     
     \ /
      Last update: 2006-12-10 21:55    [W:0.027 / U:0.040 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site