1 //
2 // Copyright (C) 2009 The Android Open Source Project
3 //
4 // Licensed under the Apache License, Version 2.0 (the "License");
5 // you may not use this file except in compliance with the License.
6 // You may obtain a copy of the License at
7 //
8 // http://www.apache.org/licenses/LICENSE-2.0
9 //
10 // Unless required by applicable law or agreed to in writing, software
11 // distributed under the License is distributed on an "AS IS" BASIS,
12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 // See the License for the specific language governing permissions and
14 // limitations under the License.
15 //
16
17 #include "update_engine/payload_consumer/bzip_extent_writer.h"
18
19 using std::vector;
20
21 namespace chromeos_update_engine {
22
23 namespace {
24 const brillo::Blob::size_type kOutputBufferLength = 16 * 1024;
25 }
26
Init(FileDescriptorPtr fd,const vector<Extent> & extents,uint32_t block_size)27 bool BzipExtentWriter::Init(FileDescriptorPtr fd,
28 const vector<Extent>& extents,
29 uint32_t block_size) {
30 // Init bzip2 stream
31 int rc = BZ2_bzDecompressInit(&stream_,
32 0, // verbosity. (0 == silent)
33 0); // 0 = faster algo, more memory
34
35 TEST_AND_RETURN_FALSE(rc == BZ_OK);
36
37 return next_->Init(fd, extents, block_size);
38 }
39
Write(const void * bytes,size_t count)40 bool BzipExtentWriter::Write(const void* bytes, size_t count) {
41 brillo::Blob output_buffer(kOutputBufferLength);
42
43 // Copy the input data into |input_buffer_| only if |input_buffer_| already
44 // contains unconsumed data. Otherwise, process the data directly from the
45 // source.
46 const uint8_t* input = reinterpret_cast<const uint8_t*>(bytes);
47 const uint8_t* input_end = input + count;
48 if (!input_buffer_.empty()) {
49 input_buffer_.insert(input_buffer_.end(), input, input_end);
50 input = input_buffer_.data();
51 input_end = input + input_buffer_.size();
52 }
53 stream_.next_in = reinterpret_cast<char*>(const_cast<uint8_t*>(input));
54 stream_.avail_in = input_end - input;
55
56 for (;;) {
57 stream_.next_out = reinterpret_cast<char*>(output_buffer.data());
58 stream_.avail_out = output_buffer.size();
59
60 int rc = BZ2_bzDecompress(&stream_);
61 TEST_AND_RETURN_FALSE(rc == BZ_OK || rc == BZ_STREAM_END);
62
63 if (stream_.avail_out == output_buffer.size())
64 break; // got no new bytes
65
66 TEST_AND_RETURN_FALSE(
67 next_->Write(output_buffer.data(),
68 output_buffer.size() - stream_.avail_out));
69
70 if (rc == BZ_STREAM_END)
71 CHECK_EQ(stream_.avail_in, 0u);
72 if (stream_.avail_in == 0)
73 break; // no more input to process
74 }
75
76 // Store unconsumed data (if any) in |input_buffer_|.
77 if (stream_.avail_in || !input_buffer_.empty()) {
78 brillo::Blob new_input_buffer(input_end - stream_.avail_in, input_end);
79 new_input_buffer.swap(input_buffer_);
80 }
81
82 return true;
83 }
84
EndImpl()85 bool BzipExtentWriter::EndImpl() {
86 TEST_AND_RETURN_FALSE(input_buffer_.empty());
87 TEST_AND_RETURN_FALSE(BZ2_bzDecompressEnd(&stream_) == BZ_OK);
88 return next_->End();
89 }
90
91 } // namespace chromeos_update_engine
92