Re: [Nmh-workers] corruption when attaching all-null files

[Paul Fox]

ralph wrote:
 > Hi Paul,
 > 
 > Sorry for the delay in replying, moving house...
 > 
 > > > >         case CT_TEXT:
 > > > >             if (contains8bit && !containsnul && !linelen && !linespace 
 > > > > && !checksw)
 > > > >                 ct->c_encoding = CE_8BIT;
 > > > >             else if (contains8bit || containsnul || linelen || 
 > > > > linespace || checksw)
 > > > >                 ct->c_encoding = CE_QUOTED;
 > > > >             else
 > > > >                 ct->c_encoding = CE_7BIT;
 > > > >             break;
 > > >
 > > >     case CT_TEXT:
 > > >         if (contains8bit)
 > > >             ct->c_encoding = (containsnul || linelen || linespace || 
 > > > checksw) ?
 > > >                 CE_QUOTED : CE_8BIT;
 > > >         else
 > > >             ct->c_encoding = CE_7BIT;
 > >
 > > i agree that the logic is cumbersome, but that doesn't look like a
 > > correct translation to me.  how about this:
 > >
 > >    needs_q_p = (containsnul || linelen || linespace || checksw);
 > >    case CT_TEXT:
 > >        if (needs_q_p)
 > >                  ct->c_encoding = CE_QUOTED;
 > >        else if (contains8bit)
 > >                  ct->c_encoding = CE_8BIT;
 > >        else
 > >                  ct->c_encoding = CE_7BIT;
 > 
 > I agree, mine was wrong, yours is correct and better expressed than the
 > original.  I blame sticking my oar in when I didn't have the time.  :-)
 > Out of interest, I followed Thompson's advice of "When in doubt, use
 > brute force";  it might entertain.

nice!  i'm pretty sure i would not have thought of testing C code
by running it through an awk interpreter.  :-)

fyi, i committed my version sometime last week, after taking a slightly
different approach to verifying correctness.  i presented the three
versions to my wife as a code review challenge.  ;-)

paul


 >     $ gen() { b=$((2**5)) && seq $b $((2 * b - 1)) | sed 's/$/pc/; 1s/^/2o/' 
 > |
 >     >     dc | sed 's/./ &/g; s/...//'; }
 >     $
 >     $ assign='{contains8bit = $1; containsnul = $2; linelen = $3;
 >     >     linespace = $4; checksw = $5}'
 >     $ print='{print $0, c_encoding}'
 >     $
 >     $ orig='
 >     >     {
 >     >         if (contains8bit && !containsnul && !linelen && !linespace && 
 > !checksw)
 >     >             c_encoding = "CE_8BIT"
 >     >         else if (contains8bit || containsnul || linelen || linespace 
 > || checksw)
 >     >             c_encoding = "CE_QUOTED"
 >     >         else
 >     >             c_encoding = "CE_7BIT"
 >     >     }
 >     > '
 >     $
 >     $ ralph='
 >     >     {
 >     >         if (contains8bit)
 >     >             c_encoding = (containsnul || linelen || linespace || 
 > checksw) ?
 >     >                 "CE_QUOTED" : "CE_8BIT"
 >     >         else
 >     >             c_encoding = "CE_7BIT"
 >     >     }
 >     > '
 >     $
 >     $ paul='
 >     >     {
 >     >         if (containsnul || linelen || linespace || checksw)
 >     >             c_encoding = "CE_QUOTED"
 >     >         else if (contains8bit)
 >     >             c_encoding = "CE_8BIT"
 >     >         else
 >     >             c_encoding = "CE_7BIT"
 >     >     }
 >     > '
 >     $
 >     $ gen | awk "$assign $orig $print"
 >     0 0 0 0 0 CE_7BIT
 >     0 0 0 0 1 CE_QUOTED
 >     0 0 0 1 0 CE_QUOTED
 >     0 0 0 1 1 CE_QUOTED
 >     0 0 1 0 0 CE_QUOTED
 >     0 0 1 0 1 CE_QUOTED
 >     0 0 1 1 0 CE_QUOTED
 >     0 0 1 1 1 CE_QUOTED
 >     0 1 0 0 0 CE_QUOTED
 >     0 1 0 0 1 CE_QUOTED
 >     0 1 0 1 0 CE_QUOTED
 >     0 1 0 1 1 CE_QUOTED
 >     0 1 1 0 0 CE_QUOTED
 >     0 1 1 0 1 CE_QUOTED
 >     0 1 1 1 0 CE_QUOTED
 >     0 1 1 1 1 CE_QUOTED
 >     1 0 0 0 0 CE_8BIT
 >     1 0 0 0 1 CE_QUOTED
 >     1 0 0 1 0 CE_QUOTED
 >     1 0 0 1 1 CE_QUOTED
 >     1 0 1 0 0 CE_QUOTED
 >     1 0 1 0 1 CE_QUOTED
 >     1 0 1 1 0 CE_QUOTED
 >     1 0 1 1 1 CE_QUOTED
 >     1 1 0 0 0 CE_QUOTED
 >     1 1 0 0 1 CE_QUOTED
 >     1 1 0 1 0 CE_QUOTED
 >     1 1 0 1 1 CE_QUOTED
 >     1 1 1 0 0 CE_QUOTED
 >     1 1 1 0 1 CE_QUOTED
 >     1 1 1 1 0 CE_QUOTED
 >     1 1 1 1 1 CE_QUOTED
 >     $
 >     $ gen | awk "$assign $ralph $print"
 >     0 0 0 0 0 CE_7BIT
 >     0 0 0 0 1 CE_7BIT
 >     0 0 0 1 0 CE_7BIT
 >     0 0 0 1 1 CE_7BIT
 >     0 0 1 0 0 CE_7BIT
 >     0 0 1 0 1 CE_7BIT
 >     0 0 1 1 0 CE_7BIT
 >     0 0 1 1 1 CE_7BIT
 >     0 1 0 0 0 CE_7BIT
 >     0 1 0 0 1 CE_7BIT
 >     0 1 0 1 0 CE_7BIT
 >     0 1 0 1 1 CE_7BIT
 >     0 1 1 0 0 CE_7BIT
 >     0 1 1 0 1 CE_7BIT
 >     0 1 1 1 0 CE_7BIT
 >     0 1 1 1 1 CE_7BIT
 >     1 0 0 0 0 CE_8BIT
 >     1 0 0 0 1 CE_QUOTED
 >     1 0 0 1 0 CE_QUOTED
 >     1 0 0 1 1 CE_QUOTED
 >     1 0 1 0 0 CE_QUOTED
 >     1 0 1 0 1 CE_QUOTED
 >     1 0 1 1 0 CE_QUOTED
 >     1 0 1 1 1 CE_QUOTED
 >     1 1 0 0 0 CE_QUOTED
 >     1 1 0 0 1 CE_QUOTED
 >     1 1 0 1 0 CE_QUOTED
 >     1 1 0 1 1 CE_QUOTED
 >     1 1 1 0 0 CE_QUOTED
 >     1 1 1 0 1 CE_QUOTED
 >     1 1 1 1 0 CE_QUOTED
 >     1 1 1 1 1 CE_QUOTED
 >     $
 >     $ gen | awk "$assign $orig $print" | sha1sum
 >     cc11d1f3c3f048242a134f0f54e434c6662878d7  -
 >     $ gen | awk "$assign $paul $print" | sha1sum
 >     cc11d1f3c3f048242a134f0f54e434c6662878d7  -
 >     $
 > 
 > Cheers, Ralph.
 > 
 > _______________________________________________
 > Nmh-workers mailing list
 > address@hidden
 > https://lists.nongnu.org/mailman/listinfo/nmh-workers

=----------------------
 paul fox, address@hidden (arlington, ma, where it's 56.8 degrees)