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>

1 files changed, 98 insertions, 0 deletions

diff --git a/fxbarcode/oned/BC_OnedEAN13Writer_unittest.cpp b/fxbarcode/oned/BC_OnedEAN13Writer_unittest.cpp
new file mode 100644
index 0000000000..932e1f42c8
--- /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