zlib decompression for chromoting

remoting/base/decompressor_zlib_unittest.cc

+// Copyright (c) 2010 The Chromium 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 <stdlib.h>
+
+#include "remoting/base/compressor_zlib.h"
+#include "remoting/base/decompressor_zlib.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+static void GenerateTestData(uint8* data, int size, int seed) {
+  srand(seed);
+  for (int i = 0; i < size; ++i)
+    data[i] = rand() % 256;
+}
+
+// Keep compressing |input_data| into |output_data| until the last
+// bytes is consumed.
+//
+// The compressed size is written to |compressed_size|.
+static void Compress(remoting::Compressor* compressor,
+                     const uint8* input_data, int input_size,
+                     uint8* output_data, int output_size,
+                     int* compressed_size) {
+  *compressed_size = 0;
+  while (true) {
+    int consumed, written;
+    bool ret = compressor->Process(input_data, input_size,
+                                   output_data, output_size,
+                                   &consumed, &written);
+    input_data += consumed;
+    input_size -= consumed;
+    output_data += written;
+    output_size -= written;
+    *compressed_size += written;
+
+    if (!ret)
+      break;
+  }
+}
+
+// The decompressed size is written to |decompressed_size|.
+static void Decompress(remoting::Decompressor* decompressor,
+                       const uint8* input_data, int input_size,
+                       uint8* output_data, int output_size,
+                       int* decompressed_size) {
+  *decompressed_size = 0;
+  while (true) {
+    int consumed, written;
+    bool ret = decompressor->Process(input_data, input_size,
+                                     output_data, output_size,
+                                     &consumed, &written);
+    input_data += consumed;
+    input_size -= consumed;
+    output_data += written;
+    output_size -= written;
+    *decompressed_size += written;
+
+    if (!ret)
+      break;
+  }
+}
+
+TEST(DecompressorZlibTest, CompressAndDecompress) {
+  static const int kRawDataSize = 1024 * 128;
+  static const int kCompressedDataSize = 2 * kRawDataSize;
+  static const int kDecompressedDataSize = kRawDataSize;
+
+  uint8 raw_data[kRawDataSize];
+  uint8 compressed_data[kCompressedDataSize];
+  uint8 decompressed_data[kDecompressedDataSize];
+
+  // Generate the test data.g
+  GenerateTestData(raw_data, kRawDataSize, 99);
+
+  // Then use the compressor.
+  remoting::CompressorZlib compressor;
+  int compressed_size = 0;
+  Compress(&compressor, raw_data, kRawDataSize,
+           compressed_data, kCompressedDataSize,
+           &compressed_size);
+
+  // Then use the decompressor.
+  remoting::DecompressorZlib decompressor;
+  int decompressed_size = 0;
+  Decompress(&decompressor, compressed_data, compressed_size,
+             decompressed_data, kDecompressedDataSize,
+             &decompressed_size);
+
+  EXPECT_EQ(kRawDataSize, decompressed_size);
+  EXPECT_EQ(0, memcmp(raw_data, decompressed_data, decompressed_size));
+}
+
+// Checks that zlib can work with a small output buffer by limiting
+// number of bytes it gets from the input.
+TEST(DecompressorZlibTest, SmallOutputBuffer) {
+  static const int kRawDataSize = 1024 * 128;
+  static const int kCompressedDataSize = 2 * kRawDataSize;
+
+  uint8 raw_data[kRawDataSize];
+  uint8 compressed_data[kCompressedDataSize];
+
+  // Generate the test data.
+  GenerateTestData(raw_data, kRawDataSize, 99);
+
+  // Then use the compressor to compress.
+  remoting::CompressorZlib compressor;
+  int compressed_size = 0;
+  Compress(&compressor, raw_data, kRawDataSize,
+           compressed_data, kCompressedDataSize,
+           &compressed_size);
+
+  // Then use the decompressor. We decompress into a 1 byte buffer
+  // every time.
+  remoting::DecompressorZlib decompressor;
+  uint8* input_data = compressed_data;
+  int input_size = compressed_size;
+  int decompressed_size = 0;
+  while (true) {
+    int consumed, written;
+    uint8 output_data;
+    bool ret = decompressor.Process(input_data, input_size,
+                                    &output_data, 1,
+                                    &consumed, &written);
+    input_data += consumed;
+    input_size -= consumed;
+
+    // Expect that there's only one byte written.
+    EXPECT_EQ(1, written);
+    decompressed_size += written;
+
+    if (!ret)
+      break;
+  }
+  EXPECT_EQ(kRawDataSize, decompressed_size);
+}