1 // Copyright 2017 PDFium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #include "fxbarcode/oned/BC_OnedEANChecksum.h" 6 7 #include "core/fxcrt/fx_extension.h" 8 9 int32_t EANCalcChecksum(const ByteString& contents) { 10 int32_t odd = 0; 11 int32_t even = 0; 12 size_t parity = 1; 13 for (size_t i = contents.GetLength(); i > 0; i--) { 14 if (parity % 2) 15 odd += FXSYS_DecimalCharToInt(contents[i - 1]); 16 else 17 even += FXSYS_DecimalCharToInt(contents[i - 1]); 18 parity++; 19 } 20 return (10 - (odd * 3 + even) % 10) % 10; 21 } 22
