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EAN13toEAN128

Function EAN13toEAN128( const aBarcode : string; aPackDate, aExpiryDate : TDateTime): string

Example​

procedure ScriptEvent(var Value: Variant);
var
  ExpiryDate: TDateTime;
begin
  ExpiryDate := EncodeDate(2027, 6, 30);

  // Zero avoids changing ExpiryDate when the implementation adds both dates.
  Value := EAN13toEAN128('9412345543219', 0, ExpiryDate);
end;

Usage​

EAN13toEAN128 builds Velox's legacy ReportBuilder-encoded GS1-128 string from a barcode and the numeric sum of two date arguments.

Parameters

NameTypeDescription
aBarcodestring, constSource barcode text. Velox Trim removes leading and trailing spaces and control characters, then only the first 12 characters are retained. No digit or length validation is performed.
aPackDateTDateTimeFirst serial date/time value. Despite the name, no packaging-date application identifier is emitted; this number is added to aExpiryDate.
aExpiryDateTDateTimeSecond serial date/time value. The numeric sum of both date arguments is formatted for application identifier 17.

Returns

A string with this exact logical layout:

SegmentContent
1ReportBuilder Char(210) start-set-C control
2ReportBuilder Char(207) FNC1 control
3Literal application identifier 02
4Literal indicator digit 1
5First 12 characters of Trim(aBarcode)
6Decimal result of CheckSum over segments 4 and 5
7Literal application identifier 17
8YYMMDD representation of aPackDate + aExpiryDate

With a valid 12-character source body, segments 4 through 6 contain 14 digits. Shorter input produces a shorter field; longer input is silently truncated.

Usage notes

Treat this as a compatibility helper for existing reports, not as a general EAN-13-to-GS1-128 conversion. Confirm the business meaning of application identifiers 02 and 17, correct the date-source decision outside the helper, and validate the final report with the applicable GS1 and trading-partner requirements.

Additional Technical Info​

EAN13toEAN128 builds one legacy ReportBuilder manual-encoding string containing start set C, FNC1, GS1 application identifier 02, a derived 14-digit content GTIN field, application identifier 17, and a six-digit date. It does not produce image data or configure the receiving barcode component.

This function has counter-intuitive legacy behaviour: it adds aPackDate and aExpiryDate as two floating-point TDateTime serial values and formats the sum as the one date following application identifier 17.

Implementation

Velox registers the function directly. The implementation calls Delphi SysUtils.Trim, then System.Copy from position 1 for 12 characters and prefixes the literal indicator 1. It passes that result to Velox CheckSum, converts the returned integer with SysUtils.IntToStr, and concatenates the hard-coded ReportBuilder characters and application identifiers.

For the final segment it calls Velox vxFormatDateTime('YYMMDD', aPackDate + aExpiryDate). That wrapper creates TFormatSettings from the Windows system default locale and delegates to the SysUtils.DateTimeToString overload that receives explicit format settings.

Behaviour

The initial string characters are U+00D2 (Ò) and U+00CF (Ï) in the current Delphi string representation. The shipped ReportBuilder Code 128 implementation interprets those values as its private start-C and FNC1 controls. They are not human-readable GS1 data and are not a general-purpose Code 128 byte sequence.

Application identifier 02 represents the GTIN of contained trade items and expects a 14-digit data field. Application identifier 17 represents an expiry date in YYMMDD form. The function assembles those labels but does not enforce their GS1 semantic prerequisites.

Edge cases and quirks

  • aPackDate + aExpiryDate adds two dates' serial-day counts; it does not add an interval to a date or choose between two dates. For two ordinary modern dates the result is typically a date many decades later. The example uses 0 for aPackDate solely to leave the expiry serial unchanged, because Delphi TDateTime(0) is the numeric zero corresponding to 30 December 1899.
  • The function emits no packaging-date field. The parameter name aPackDate does not describe a separate output segment.
  • The original barcode's thirteenth digit is ignored along with every later character. The function recomputes a check digit after prefixing indicator 1; it does not verify the input's existing EAN-13 check digit.
  • Trimming affects only the two ends. Embedded spaces or other non-digits remain and cause CheckSum to raise when it converts them.
  • A source shorter than 12 characters remains short. Empty or whitespace-only input forms the data value 1, for which CheckSum returns 7; the function still returns an assembled string.
  • YYMMDD uses a two-digit year and contains no century. The fixed numeric format avoids names and separators, but the terminal formatter still receives Windows system-locale settings and a Delphi TDateTime value.
  • A date sum outside the range accepted by the Delphi formatter raises; there is no range check before formatting.
  • ReportBuilder automatic Code 128 encoding can remove and replace the explicit start control. To preserve manual set selection, the receiving report must use the compatible manual-encoding configuration.

Side effects

The function allocates and returns a string only. It does not modify the dates, configure ReportBuilder, create an image or access a printer or scanner.

Errors

An invalid character in the selected barcode text can propagate EConvertError from CheckSum and StrToInt. Date conversion or formatting exceptions propagate from the Delphi runtime. The function catches, logs and translates none of these failures.

Performance and concurrency

Work and allocations are linear in at most the first 12 trimmed barcode characters, apart from the runtime cost of trimming the full input and formatting the date. The function and its Velox helpers use local state. The explicit TFormatSettings instance avoids dependence on mutable global formatting variables during the terminal formatting call.

Related entries

  • CheckSum calculates the data check digit inserted by this function.
  • StartGS1128C returns the same ReportBuilder start-C and FNC1 prefix used here.

External references

Created 2026-07-15