Re: Help with cprdata

["Keith Carpenter" <CarpCon@xxxxxxx>]

John,

The problem is your variable Compressed is too small.

Not sure how you arrived at 44 bytes as the size, but in this example,
cprdata actually needs a larger field (62 bytes).

Part of the reason for the larger size is that the compressed data has a
header structure (first 12 bytes). The other is relatively small amount of
data being compressed (compression routine overhead).

To see any effective compression results you need to use cprdata on a larger
chunk of data. Your example is closer to a worst case example.

Assuming you use a large enough compression buffer, you can get the actual
size of the compressed data from the header.
Bytes 5-8  is the compressed len  (10u 0)
Bytes 9-12 is the uncompressed len (10u 0)


Keith



----- Original Message ----- 
From: "Jon Paris" <Jon.Paris@xxxxxxxxxxxxxx>
To: "Rpg400" <rpg400-l@xxxxxxxxxxxx>
Sent: Thursday, July 01, 2004 3:15 PM
Subject: Help with cprdata


> I'm having a senior citizen moment I think.  I just can't see why this
puppy
> is blowing up on me with a nasty template error.
>
> What am I missing?  The C manual defines it like so:
> int cprdata (_SPCPTR result,
> int result_length,
> _SPCPTRCN source,
> int src_length);
>
> And my RPG code is:
>
>      d Compress        pr            10i 0 Extproc('cprdata')
>      d   Output                   32000a   Options(*Varsize)
>      d   OutputLen                   10i 0 Value
>      d   Source                   32000a   Options(*Varsize)
>      d   SourceLen                   10i 0 Value
>
>      D Compressed      S             44a
>      D CompressedLen   S              2s 0
>      D Source          S             52a
>
>       /Free
>         Source = *All'Jon and Susan - ';
>         Dsply Source;
>         CompressedLen = Compress(Compressed: %Size(Compressed):
>                                  Source:     %Size(Source));
>
> Jon Paris
> Partner400
> www.Partner400.com
>
> --
> This is the RPG programming on the AS400 / iSeries (RPG400-L) mailing list
> To post a message email: RPG400-L@xxxxxxxxxxxx
> To subscribe, unsubscribe, or change list options,
> visit: http://lists.midrange.com/mailman/listinfo/rpg400-l
> or email: RPG400-L-request@xxxxxxxxxxxx
> Before posting, please take a moment to review the archives
> at http://archive.midrange.com/rpg400-l.
>
>