text: /*
   * Copyright (c) 2020-2021, the SerenityOS developers.
   *
   * SPDX-License-Identifier: BSD-2-Clause
   */
  
  #include <LibTest/TestCase.h>
  
  #include <AK/Array.h>
  #include <AK/MemoryStream.h>
  #include <AK/Random.h>
  #include <LibCompress/Deflate.h>
  #include <cstring>
  
  TEST_CASE(canonical_code_simple)
  {
      Array<u8, 32> const code {
          0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05,
          0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05,
          0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05
      };
      Array<u8, 6> const input {
          0x00, 0x42, 0x84, 0xa9, 0xb0, 0x15
      };
      Array<u32, 9> const output {
          0x00, 0x01, 0x01, 0x02, 0x03, 0x05, 0x08, 0x0d, 0x15
      };
  
      auto const huffman = Compress::CanonicalCode::from_bytes(code).value();
      auto memory_stream = InputMemoryStream { input };
      auto bit_stream = InputBitStream { memory_stream };
  
      for (size_t idx = 0; idx < 9; ++idx)
          EXPECT_EQ(huffman.read_symbol(bit_stream), output[idx]);
  }
  
  TEST_CASE(canonical_code_complex)
  {
      Array<u8, 6> const code {
          0x03, 0x02, 0x03, 0x03, 0x02, 0x03
      };
      Array<u8, 4> const input {
          0xa1, 0xf3, 0xa1, 0xf3
      };
      Array<u32, 12> const output {
          0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05
      };
  
      auto const huffman = Compress::CanonicalCode::from_bytes(code).value();
      auto memory_stream = InputMemoryStream { input };
      auto bit_stream = InputBitStream { memory_stream };
  
      for (size_t idx = 0; idx < 12; ++idx)
          EXPECT_EQ(huffman.read_symbol(bit_stream), output[idx]);
  }
  
  TEST_CASE(deflate_decompress_compressed_block)
  {
      Array<u8, 28> const compressed {
          0x0B, 0xC9, 0xC8, 0x2C, 0x56, 0x00, 0xA2, 0x44, 0x85, 0xE2, 0xCC, 0xDC,
          0x82, 0x9C, 0x54, 0x85, 0x92, 0xD4, 0x8A, 0x12, 0x85, 0xB4, 0x4C, 0x20,
          0xCB, 0x4A, 0x13, 0x00
      };
  
      const u8 uncompressed[] = "This is a simple text file :)";
  
      auto const decompressed = Compress::DeflateDecompressor::decompress_all(compressed);
      EXPECT(decompressed.value().bytes() == ReadonlyBytes({ uncompressed, sizeof(uncompressed) - 1 }));
  }
  
  TEST_CASE(deflate_decompress_uncompressed_block)
  {
      Array<u8, 18> const compressed {
          0x01, 0x0d, 0x00, 0xf2, 0xff, 0x48, 0x65, 0x6c, 0x6c, 0x6f, 0x2c, 0x20,
          0x57, 0x6f, 0x72, 0x6c, 0x64, 0x21
      };
  
      const u8 uncompressed[] = "Hello, World!";
  
      auto const decompressed = Compress::DeflateDecompressor::decompress_all(compressed);
      EXPECT(decompressed.value().bytes() == (ReadonlyBytes { uncompressed, sizeof(uncompressed) - 1 }));
  }
  
  TEST_CASE(deflate_decompress_multiple_blocks)
  {
      Array<u8, 84> const compressed {
          0x00, 0x1f, 0x00, 0xe0, 0xff, 0x54, 0x68, 0x65, 0x20, 0x66, 0x69, 0x72,
          0x73, 0x74, 0x20, 0x62, 0x6c, 0x6f, 0x63, 0x6b, 0x20, 0x69, 0x73, 0x20,
          0x75, 0x6e, 0x63, 0x6f, 0x6d, 0x70, 0x72, 0x65, 0x73, 0x73, 0x65, 0x64,
          0x53, 0x48, 0xcc, 0x4b, 0x51, 0x28, 0xc9, 0x48, 0x55, 0x28, 0x4e, 0x4d,
          0xce, 0x07, 0x32, 0x93, 0x72, 0xf2, 0x93, 0xb3, 0x15, 0x32, 0x8b, 0x15,
          0x92, 0xf3, 0x73, 0x0b, 0x8a, 0x52, 0x8b, 0x8b, 0x53, 0x53, 0xf4, 0x00
      };
  
      const u8 uncompressed[] = "The first block is uncompressed and the second block is compressed.";
  
      auto const decompressed = Compress::DeflateDecompressor::decompress_all(compressed);
      EXPECT(decompressed.value().bytes() == (ReadonlyBytes { uncompressed, sizeof(uncompressed) - 1 }));
  }
  
  TEST_CASE(deflate_decompress_zeroes)
  {
      Array<u8, 20> const compressed {
          0xed, 0xc1, 0x01, 0x0d, 0x00, 0x00, 0x00, 0xc2, 0xa0, 0xf7, 0x4f, 0x6d,
          0x0f, 0x07, 0x14, 0x00, 0x00, 0x00, 0xf0, 0x6e
      };
  
      Array<u8, 4096> const uncompressed { 0 };
  
      auto const decompressed = Compress::DeflateDecompressor::decompress_all(compressed);
      EXPECT(uncompressed == decompressed.value().bytes());
  }
  
  TEST_CASE(deflate_round_trip_store)
  {
      auto original = ByteBuffer::create_uninitialized(1024).release_value();
      fill_with_random(original.data(), 1024);
      auto compressed = Compress::DeflateCompressor::compress_all(original, Compress::DeflateCompressor::CompressionLevel::STORE);
      EXPECT(compressed.has_value());
      auto uncompressed = Compress::DeflateDecompressor::decompress_all(compressed.value());
      EXPECT(uncompressed.has_value());
      EXPECT(uncompressed.value() == original);
  }
  
  TEST_CASE(deflate_round_trip_compress)
  {
      auto original = ByteBuffer::create_zeroed(2048).release_value();
      fill_with_random(original.data(), 1024); // we pre-filled the second half with 0s to make sure we test back references as well
      // Since the different levels just change how much time is spent looking for better matches, just use fast here to reduce test time
      auto compressed = Compress::DeflateCompressor::compress_all(original, Compress::DeflateCompressor::CompressionLevel::FAST);
      EXPECT(compressed.has_value());
      auto uncompressed = Compress::DeflateDecompressor::decompress_all(compressed.value());
      EXPECT(uncompressed.has_value());
      EXPECT(uncompressed.value() == original);
  }
  
  TEST_CASE(deflate_round_trip_compress_large)
  {
      auto size = Compress::DeflateCompressor::block_size * 2;
      auto original = ByteBuffer::create_uninitialized(size).release_value(); // Compress a buffer larger than the maximum block size to test the sliding window mechanism
      fill_with_random(original.data(), size);
      // Since the different levels just change how much time is spent looking for better matches, just use fast here to reduce test time
      auto compressed = Compress::DeflateCompressor::compress_all(original, Compress::DeflateCompressor::CompressionLevel::FAST);
      EXPECT(compressed.has_value());
      auto uncompressed = Compress::DeflateDecompressor::decompress_all(compressed.value());
      EXPECT(uncompressed.has_value());
      EXPECT(uncompressed.value() == original);
  }
  
  TEST_CASE(deflate_compress_literals)
  {
      // This byte array is known to not produce any back references with our lz77 implementation even at the highest compression settings
      Array<u8, 0x13> test { 0, 0, 0, 0, 0x72, 0, 0, 0xee, 0, 0, 0, 0x26, 0, 0, 0, 0x28, 0, 0, 0x72 };
      auto compressed = Compress::DeflateCompressor::compress_all(test, Compress::DeflateCompressor::CompressionLevel::GOOD);
      EXPECT(compressed.has_value());
  }
  