Browse Prior Art Database

DBCS Length Support - PC to Host

IP.com Disclosure Number: IPCOM000102644D
Original Publication Date: 1990-Dec-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 50K

Publishing Venue

IBM

Related People

DeBellevue, J: AUTHOR [+4]

Abstract

This article describes a technique for validating the proper lengths of DBCS PC fields prior to host conversion

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 62% of the total text.

DBCS Length Support - PC to Host

       This article describes a technique for validating the
proper lengths of DBCS PC fields prior to host conversion

      The handling of mixed SBCS/DBCS strings is difficult to do.
There are differences in the datastream architectures of the PC and
the host, specifically between the ASCII format on the PC and the
EBCDIC format on the host.  When a mixed SBCS/DBCS string is present
on the PC, the code point range determines whether the character is
SBCS or the first byte of a DBCS (two-byte) character.  Characters
are either single byte in length or two bytes in length.  On the host
there is no such code point range, so special characters called SO
and SI are used to separate DBCS characters from SBCS characters.
Thus, if a field consists of 2 SBCS characters and 3 DBCS characters,
its length on the PC would be 8, while its length on the host would
be 10.

      If a host field has a maximum length, the length of what is
actually available for the user data is 2 bytes less each time a
change is made from SBCS to DBCS.  A 12-byte data entry field could
contain:
- 12 SBCS characters (12 user-entered characters)
- 6 DBCS characters (6 user-entered characters)
- A control character, 4 DBCS characters, a control character, and 2
SBCS characters (6 user-entered characters)
- A control character, 2 DBCS characters, a control character, 2 SBCS
characters, a control character, 1 DBCS character, and a control
character. (5 user-en...