Add a brotli decompressor in bsdiff

This CL implements the brotli decompressor used in PatchReader. Also
extract the CompressorType and patch's MagicHeader to a common header file.

Bug: 34220646
Test: Run bsdiff/bspatch with brotli compressor/decompressor over a list
of files from angler's system image.

Change-Id: I76e11168075c6481490ffbc025ec4ca81e828732

1 files changed, 61 insertions, 0 deletions

diff --git a/brotli_decompressor.cc b/brotli_decompressor.cc
new file mode 100644
index 0000000..683e391
--- /dev/null
+++ b/brotli_decompressor.cc
@@ -0,0 +1,61 @@
+// Copyright 2017 The Chromium OS 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 "bsdiff/brotli_decompressor.h"
+
+#include "bsdiff/logging.h"
+
+using std::endl;
+
+namespace bsdiff {
+
+bool BrotliDecompressor::SetInputData(const uint8_t* input_data, size_t size) {
+  brotli_decoder_state_ =
+      BrotliDecoderCreateInstance(nullptr, nullptr, nullptr);
+  if (brotli_decoder_state_ == nullptr) {
+    LOG(ERROR) << "Failed to initialize brotli decoder." << endl;
+    return false;
+  }
+  next_in_ = input_data;
+  available_in_ = size;
+  return true;
+}
+
+bool BrotliDecompressor::Read(uint8_t* output_data, size_t bytes_to_output) {
+  auto next_out = output_data;
+  size_t available_out = bytes_to_output;
+
+  while (available_out > 0) {
+    // The brotli decoder will update |available_in_|, |available_in_|,
+    // |next_out| and |available_out|.
+    BrotliDecoderResult result = BrotliDecoderDecompressStream(
+        brotli_decoder_state_, &available_in_, &next_in_, &available_out,
+        &next_out, nullptr);
+
+    if (result == BROTLI_DECODER_RESULT_ERROR) {
+      LOG(ERROR) << "Decompression failed with "
+                 << BrotliDecoderErrorString(
+                        BrotliDecoderGetErrorCode(brotli_decoder_state_))
+                 << endl;
+      return false;
+    } else if (result == BROTLI_DECODER_RESULT_NEEDS_MORE_INPUT) {
+      LOG(ERROR) << "Decompressor reached EOF while reading from input stream."
+                 << endl;
+      return false;
+    }
+  }
+  return true;
+}
+
+bool BrotliDecompressor::Close() {
+  if (!BrotliDecoderIsFinished(brotli_decoder_state_)) {
+    LOG(ERROR) << "Unfinished brotli decoder." << endl;
+    return false;
+  }
+
+  BrotliDecoderDestroyInstance(brotli_decoder_state_);
+  return true;
+}
+
+}  // namespace bsdiff
\ No newline at end of file