JBig2_BitStream_unittest.cpp

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// Copyright 2017 The PDFium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
 
#include "core/fxcodec/jbig2/JBig2_BitStream.h"
 
#include "testing/gtest/include/gtest/gtest.h"
 
TEST(JBig2_BitStream, ReadNBits) {
  const uint8_t kData[] = {0xb1};  // 10110001
  CJBig2_BitStream stream(kData, 0);
 
  uint32_t val1;
  EXPECT_EQ(0, stream.readNBits(1, &val1));
  EXPECT_EQ(1U, val1);
 
  int32_t val2;
  EXPECT_EQ(0, stream.readNBits(1, &val2));
  EXPECT_EQ(0, val2);
 
  EXPECT_EQ(0, stream.readNBits(2, &val2));
  EXPECT_EQ(3, val2);
 
  EXPECT_EQ(0, stream.readNBits(4, &val2));
  EXPECT_EQ(1, val2);
}
 
TEST(JBig2_BitStream, ReadNBitsLargerThenData) {
  const uint8_t kData[] = {0xb1};  // 10110001
  CJBig2_BitStream stream(kData, 42);
 
  uint32_t val1;
  EXPECT_EQ(0, stream.readNBits(10, &val1));
  EXPECT_EQ(0xb1U, val1);
}
 
TEST(JBig2_BitStream, ReadNBitsNullStream) {
  CJBig2_BitStream stream({}, 0);
 
  uint32_t val1;
  EXPECT_EQ(-1, stream.readNBits(1, &val1));
 
  int32_t val2;
  EXPECT_EQ(-1, stream.readNBits(2, &val2));
}
 
TEST(JBig2_BitStream, ReadNBitsOutOfBounds) {
  const uint8_t kData[] = {0xb1};  // 10110001
  CJBig2_BitStream stream(kData, 42);
 
  uint32_t val1;
  EXPECT_EQ(0, stream.readNBits(8, &val1));
 
  int32_t val2;
  EXPECT_EQ(-1, stream.readNBits(2, &val2));
}
 
TEST(JBig2_BitStream, ReadNBitsWhereNIs36) {
  const uint8_t kData[] = {0xb0, 0x01, 0x00, 0x00, 0x40};
  CJBig2_BitStream stream(kData, 42);
 
  // This will shift off the top two bits and they end up lost.
  uint32_t val1;
  EXPECT_EQ(0, stream.readNBits(34, &val1));
  EXPECT_EQ(0xc0040001U, val1);
}