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// Copyright 2017 PDFium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "fxbarcode/oned/BC_OnedEANChecksum.h"
#include "core/fxcrt/fx_extension.h"
int32_t EANCalcChecksum(const ByteString& contents) {
int32_t odd = 0;
int32_t even = 0;
size_t parity = 1;
for (size_t i = contents.GetLength(); i > 0; i--) {
if (parity % 2)
odd += FXSYS_DecimalCharToInt(contents[i - 1]);
else
even += FXSYS_DecimalCharToInt(contents[i - 1]);
parity++;
}
return (10 - (odd * 3 + even) % 10) % 10;
}