Method: GetCheckSum - Syntax 1

(TBarcode2D_PDF417)

Returns the check sum of a barcode text that will be encoded into each symbol in a Macro PDF417 set.

Syntax:

type

{ Defined in the pPDF417Com unit }

TPDF417_Option = (poIgnoreShiftBeforeECI, poFirst903TextAlphaLatch, poFirst904TextMixedLatch, po906TextAlphaLatch, po907TextAlphaLatch, po908TextAlphaLatch, po910TextAlphaLatch, po912TextAlphaLatch, po914TextAlphaLatch, po915TextAlphaLatch, poFirstFNC1MatchAI01, poMicroPDF417Explicit901);

{ Defined in the pPDF417Com unit }

TPDF417_Options = set of TPDF417_Option;

function GetCheckSum(Barcode: string; AllowEscape: Boolean; var InvalidIndex: Integer; Options: TPDF417_Options = []): string; virtual;

Description:

The method returns the check sum of a barcode text that will be encoded into a Macro PDF417 set. The value will be used in the macro PDF417 control information block, and the macro PDF417 control information block will be used by each symbol in the Macro PDF417 set. See also the "Macro PDF417" section in the "TBarcode2D_PDF417" article.

Parameters:
Return:

If the method succeeds, it returns the check sum value, it's a 16-bit word value, in decimal string format. And the InvalidIndex parameter returns zero. If the method fails, the InvalidIndex parameter returns a position index of first invalid character, it's an integer value greater than 0.

The result string can be directly used as the check sum in the Macro PDF417 control information block. For example:

var

full_barcode, check_sum, macro_block: string;

invalid_index: integer;

begin

full_barcode := '......';

check_sum := GetCheckSum(full_barcode, false, invalid_index, []);

if invalid_index > 0 then exit;

macro_block := '\s[1,001287023,,5,2008-12-03 05:30:00,,USA,,' + check_sum + ']';

//.....

See also the "Macro PDF417" section in the "TBarcode2D_PDF417" article.

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