date_parse - date-parsing routine and apps

For a while now I've been somewhat unhappy with the various date-parsing routines available - yacc-based, lex-based, ad-hoc. Large code size and not very portable are the main complaints. So I wrote a new one that just does a bunch of sscanf's until one matches. Slow, but small and portable. To figure out what formats to support I did a survey of Date: lines in a bunch of Usenet articles. The following two formats accounted for more than 99% of all articles:

    DD mth YY HH:MM:SS ampm zone
    wdy, DD mth YY HH:MM:SS ampm zone
    

I added Unix ctime() format and a few others:

    wdy mth DD HH:MM:SS ampm zone YY
    HH:MM:SS ampm zone DD mth YY
    DD mth YY
    HH:MM:SS ampm
    

No-zone, no-seconds, and no-am/pm versions of each are also supported. Note that dd/mm/yy and mm/dd/yy are NOT supported - those formats are dumb.

Aside from the date-parsing routine, this package includes some programs that exercise it:

• date_sort - sort a file's lines by date
• date_order - order a list of files by netnews/mail-format Date: lines
• deltime - subtract two times and show the difference
• timegraph - graph or histogram time-based data
• xmit_time - figure transmission time of netnews articles

See the manual entries for more details. For some sample runs of the timegraph command, check out the ACME Labs web stats page.

ACME Labs / Software / date_parse