Method: GetCheckSum - Syntax 1

(TBarcode2D_MicroPDF417)

Returns the check sum of a barcode text that will be encoded into a series of structured append symbols.

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;

{ Defined in the pMicroPDF417 unit }

TMicroPDF417_Options = TPDF417_Options;

function GetCheckSum(Barcode: string; AllowEscape: Boolean; var InvalidIndex: Integer; Options: TMicroPDF417_Options = []): string; virtual;

Description:

The method returns the check sum of a barcode text that will be encoded into a series of structured append symbols. The value will be used in the structured append block, and the structured append block will be used by each symbol in the series of MicroPDF417 structured append symbols. See also the "Structured append" section in the "TBarcode2D_MicroPDF417" 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 structured append block. For example:

var

full_barcode, check_sum, structuredappend_block: string;

invalid_index: integer;

begin

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

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

if invalid_index > 0 then exit;

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

//.....

See also the "Sturctured append" section in the "TBarcode2D_MicroPDF417" article.

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