IBM AS/400E manual Binary, Ebcdicjcd

In this mode, the server will convert everything into the EBCDIC CCSID of the job. The server checks the Entity bodies for a charset tag. If found, the server will convert the corresponding ASCII CCSID to the EBCDIC CCSID of the job. If the server does not find a charset tag, it uses the value of the DefaultNetCCSID configuration directive as the conversion CCSID. In addition, the system converts escaped octets from ASCII to EBCDIC, eliminating the need to perform this conversion in the CGI program.

BINARY

In this mode, the server processes environment variables (except

QUERY_STRING) the same way as EBCDIC mode. The server performs no conversions on either QUERY_STRING or stdin data.

EBCDIC_JCD

Japanese browsers can potentially send data in one of three code pages, JIS (ISO-2022-JP), S-JIS (PC-Windows), or EUC (UNIX). In this mode, the server uses a well-known JCD utility to determine which codepage to use (if not explicitly specified by a charset tag) to convert stdin data.

Table 1 summarizes the type of conversion that is performed by the server for each CGI mode.

Table 1. Conversion action for text in CGI Stdin.

CGI_MODE	Conversion	Stdin	Environment	Query_String	argv
		encoding	variables	encoding	encoding
%%BINARY%%	None	No conversion	FsCCSID	No conversion	No
					conversion
%%EBCDIC%%	NetCCSID to	FsCCSID	FsCCSID	FsCCSID	FsCCSID
	FsCCSID
%%EBCDIC%% - with	Calculate target	EBCDIC	FsCCSID	FsCCSID	FsCCSID
charset tag received	EBCDIC CCSID	equivalent of
	based on received	received
	ASCII charset tag	charset
%%EBCDIC_JCD%%	Detect input based	FsCCSID	FsCCSID	Detect ASCII	Detect ASCII
	on received data.			input based on	input based
	Convert data to			received data.	on received
	FsCCSID			Convert data to	data. Convert
				FsCCSID	data to
					FsCCSID
%%MIXED%%	NetCCSID to	FsCCSID with	CCSID 37	CCSID 37 with	CCSID37 with
(Compatability mode)	FsCCSID (receive	ASCII escape		ASCII escape	ASCII escape
	charset tag is	sequences		sequences	sequences
	ignored)

DBCS Considerations

URL-encoded forms containing DBCS data could contain ASCII octets that represent parts of DBCS characters. The server can only convert non-encoded character data. This means that it must un-encode the double-byte character set (DBCS) stdin and QUERY_STRING data before performing the conversion. In addition, it has to reassemble and re-encode the resulting EBCDIC representation before passing it to the CGI program. Because of this extra processing, CGI programs that you write to handle DBCS data may choose to receive the data as BINARY and perform all conversions to streamline the entire process.

Chapter 1. Writing Common Gateway Interface Programs 7