1// Copyright (c) 2017, the Dart project authors. Please see the AUTHORS file
2// for details. All rights reserved. Use of this source code is governed by a
3// BSD-style license that can be found in the LICENSE file.
4
5#include "bin/gzip.h"
6
7#include "platform/assert.h"
8#include "platform/globals.h"
9#include "zlib/zlib.h"
10
11namespace dart {
12namespace bin {
13
14void Decompress(const uint8_t* input,
15 intptr_t input_len,
16 uint8_t** output,
17 intptr_t* output_length) {
18 ASSERT(input != NULL);
19 ASSERT(input_len > 0);
20 ASSERT(output != NULL);
21 ASSERT(output_length != NULL);
22
23 const intptr_t kChunkSize = 256 * 1024;
24
25 // Initialize output.
26 intptr_t output_capacity = input_len * 2;
27 if (output_capacity < kChunkSize) {
28 output_capacity = kChunkSize;
29 }
30 *output = reinterpret_cast<uint8_t*>(malloc(output_capacity));
31
32 uint8_t* chunk_out = reinterpret_cast<uint8_t*>(malloc(kChunkSize));
33 z_stream strm;
34 strm.zalloc = Z_NULL;
35 strm.zfree = Z_NULL;
36 strm.opaque = Z_NULL;
37 strm.avail_in = 0;
38 strm.next_in = 0;
39 int ret = inflateInit2(&strm, 32 + MAX_WBITS);
40 ASSERT(ret == Z_OK);
41
42 intptr_t input_cursor = 0;
43 intptr_t output_cursor = 0;
44 do {
45 // Setup input.
46 intptr_t size_in = input_len - input_cursor;
47 if (size_in > kChunkSize) {
48 size_in = kChunkSize;
49 }
50 strm.avail_in = size_in;
51 strm.next_in = const_cast<uint8_t*>(&input[input_cursor]);
52
53 // Inflate until we've exhausted the current input chunk.
54 do {
55 // Setup output.
56 strm.avail_out = kChunkSize;
57 strm.next_out = &chunk_out[0];
58 // Inflate.
59 ret = inflate(&strm, Z_SYNC_FLUSH);
60 // We either hit the end of the stream or made forward progress.
61 ASSERT((ret == Z_STREAM_END) || (ret == Z_OK));
62 // Grow output buffer size.
63 intptr_t size_out = kChunkSize - strm.avail_out;
64 if (size_out > (output_capacity - output_cursor)) {
65 output_capacity *= 2;
66 ASSERT(size_out <= (output_capacity - output_cursor));
67 *output = reinterpret_cast<uint8_t*>(realloc(*output, output_capacity));
68 }
69 // Copy output.
70 memmove(&((*output)[output_cursor]), &chunk_out[0], size_out);
71 output_cursor += size_out;
72 } while (strm.avail_out == 0);
73
74 // We've processed size_in bytes.
75 input_cursor += size_in;
76
77 // We're finished decompressing when zlib tells us.
78 } while (ret != Z_STREAM_END);
79
80 inflateEnd(&strm);
81
82 *output_length = output_cursor;
83 free(chunk_out);
84}
85
86} // namespace bin
87} // namespace dart
88