Fix EAN-13 checksum and add unit tests.
Parity in EAN-13 is considered counting digits from right to left,
starting at 1.
Bug: pdfium:882
Change-Id: I3e586499091b8400daf93657eb9878f29d9e6922
Reviewed-on: https://pdfium-review.googlesource.com/12910
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: Henrique Nakashima <hnakashima@chromium.org>
diff --git a/BUILD.gn b/BUILD.gn
index ce598c6..d9e8d71 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -1951,6 +1951,7 @@
"core/fxcrt/xml/cfx_saxreader_unittest.cpp",
"core/fxcrt/xml/cfx_xmlsyntaxparser_unittest.cpp",
"fxbarcode/oned/BC_OnedCode128Writer_unittest.cpp",
+ "fxbarcode/oned/BC_OnedEAN13Writer_unittest.cpp",
"fxbarcode/pdf417/BC_PDF417HighLevelEncoder_unittest.cpp",
"xfa/fde/cfde_texteditengine_unittest.cpp",
"xfa/fgas/crt/cfgas_formatstring_unittest.cpp",
diff --git a/fxbarcode/oned/BC_OnedEAN13Writer.cpp b/fxbarcode/oned/BC_OnedEAN13Writer.cpp
index dddb9cc..e7642de 100644
--- a/fxbarcode/oned/BC_OnedEAN13Writer.cpp
+++ b/fxbarcode/oned/BC_OnedEAN13Writer.cpp
@@ -79,17 +79,16 @@
int32_t CBC_OnedEAN13Writer::CalcChecksum(const CFX_ByteString& contents) {
int32_t odd = 0;
int32_t even = 0;
- FX_STRSIZE j = 1;
- for (FX_STRSIZE i = 0; i < contents.GetLength(); i++) {
- if (j % 2) {
- odd += FXSYS_DecimalCharToInt(contents[i]);
+ FX_STRSIZE parity = 1;
+ for (FX_STRSIZE i = contents.GetLength(); i > 0; i--) {
+ if (parity % 2) {
+ odd += FXSYS_DecimalCharToInt(contents[i - 1]);
} else {
- even += FXSYS_DecimalCharToInt(contents[i]);
+ even += FXSYS_DecimalCharToInt(contents[i - 1]);
}
- j++;
+ parity++;
}
- int32_t checksum = 10 - (odd * 3 + even) % 10;
- return checksum;
+ return (10 - (odd * 3 + even) % 10) % 10;
}
uint8_t* CBC_OnedEAN13Writer::EncodeWithHint(const CFX_ByteString& contents,
diff --git a/fxbarcode/oned/BC_OnedEAN13Writer_unittest.cpp b/fxbarcode/oned/BC_OnedEAN13Writer_unittest.cpp
new file mode 100644
index 0000000..932e1f4
--- /dev/null
+++ b/fxbarcode/oned/BC_OnedEAN13Writer_unittest.cpp
@@ -0,0 +1,98 @@
+// 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_OnedEAN13Writer.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace {
+
+TEST(OnedEAN13WriterTest, Encode) {
+ CBC_OnedEAN13Writer writer;
+ int32_t width;
+ int32_t height;
+ uint8_t* encoded;
+ const char* expected;
+
+ // EAN-13 barcodes encode 13-digit numbers into 95 modules in a unidimensional
+ // disposition.
+ encoded = writer.Encode("", BCFORMAT_EAN_13, width, height);
+ EXPECT_EQ(nullptr, encoded);
+ FX_Free(encoded);
+
+ encoded = writer.Encode("123", BCFORMAT_EAN_13, width, height);
+ EXPECT_EQ(nullptr, encoded);
+ FX_Free(encoded);
+
+ encoded = writer.Encode("123456789012", BCFORMAT_EAN_13, width, height);
+ EXPECT_EQ(nullptr, encoded);
+ FX_Free(encoded);
+
+ encoded = writer.Encode("12345678901234", BCFORMAT_EAN_13, width, height);
+ EXPECT_EQ(nullptr, encoded);
+ FX_Free(encoded);
+
+ encoded = writer.Encode("1234567890128", BCFORMAT_EAN_13, width, height);
+ EXPECT_NE(nullptr, encoded);
+ EXPECT_EQ(1, height);
+ EXPECT_EQ(95, width);
+
+ expected =
+ "# #" // Start
+ // 1 implicit by LLGLGG in next 6 digits
+ " # ##" // 2 L
+ " #### #" // 3 L
+ " ### #" // 4 G
+ " ## #" // 5 L
+ " # #" // 6 G
+ " # #" // 7 G
+ " # # " // Middle
+ "# # " // 8 R
+ "### # " // 9 R
+ "### # " // 0 R
+ "## ## " // 1 R
+ "## ## " // 2 R
+ "# # " // 8 R
+ "# #"; // End
+ for (int i = 0; i < 95; i++) {
+ EXPECT_EQ(expected[i] != ' ', !!encoded[i]) << i;
+ }
+ FX_Free(encoded);
+
+ encoded = writer.Encode("7776665554440", BCFORMAT_EAN_13, width, height);
+ EXPECT_NE(nullptr, encoded);
+ EXPECT_EQ(1, height);
+ EXPECT_EQ(95, width);
+
+ expected =
+ "# #" // Start
+ // 7 implicit by LGLGLG in next 6 digits
+ " ### ##" // 7 L
+ " # #" // 7 G
+ " # ####" // 6 L
+ " # #" // 6 G
+ " # ####" // 6 L
+ " ### #" // 5 G
+ " # # " // Middle
+ "# ### " // 5 R
+ "# ### " // 5 R
+ "# ### " // 4 R
+ "# ### " // 4 R
+ "# ### " // 4 R
+ "### # " // 0 R
+ "# #"; // End
+ for (int i = 0; i < 95; i++) {
+ EXPECT_EQ(expected[i] != ' ', !!encoded[i]) << i;
+ }
+ FX_Free(encoded);
+}
+
+TEST(OnedEAN13WriterTest, Checksum) {
+ CBC_OnedEAN13Writer writer;
+ EXPECT_EQ(0, writer.CalcChecksum(""));
+ EXPECT_EQ(6, writer.CalcChecksum("123"));
+ EXPECT_EQ(8, writer.CalcChecksum("123456789012"));
+ EXPECT_EQ(0, writer.CalcChecksum("777666555444"));
+}
+
+} // namespace
