1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
3 /* This Source Code Form is subject to the terms of the Mozilla Public
4  * License, v. 2.0. If a copy of the MPL was not distributed with this
5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
6 
7 #if !defined(WavDumper_h_)
8 #  define WavDumper_h_
9 #  include <stdio.h>
10 #  include <stdint.h>
11 #  include <nsTArray.h>
12 #  include <mozilla/Unused.h>
13 #  include <mozilla/Atomics.h>
14 #  include <mozilla/DebugOnly.h>
15 #  include <mozilla/Sprintf.h>
16 #  include <ByteWriter.h>
17 
18 /**
19  * If MOZ_DUMP_AUDIO is set, this dumps a file to disk containing the output of
20  * an audio stream, in 16bits integers.
21  *
22  * The sandbox needs to be disabled for this to work.
23  */
24 class WavDumper {
25  public:
26   WavDumper() = default;
~WavDumper()27   ~WavDumper() {
28     if (mFile) {
29       fclose(mFile);
30     }
31   }
32 
Open(const char * aBaseName,uint32_t aChannels,uint32_t aRate)33   void Open(const char* aBaseName, uint32_t aChannels, uint32_t aRate) {
34     using namespace mozilla;
35 
36     if (!getenv("MOZ_DUMP_AUDIO")) {
37       return;
38     }
39 
40     static mozilla::Atomic<int> sDumpedAudioCount(0);
41 
42     char buf[100];
43     SprintfLiteral(buf, "%s-%d.wav", aBaseName, ++sDumpedAudioCount);
44     OpenExplicit(buf, aChannels, aRate);
45   }
46 
OpenExplicit(const char * aPath,uint32_t aChannels,uint32_t aRate)47   void OpenExplicit(const char* aPath, uint32_t aChannels, uint32_t aRate) {
48     mFile = fopen(aPath, "wb");
49     if (!mFile) {
50       NS_WARNING("Could not open file to DUMP a wav. Is sandboxing disabled?");
51       return;
52     }
53     const uint8_t riffHeader[] = {
54         // RIFF header
55         0x52, 0x49, 0x46, 0x46, 0x00, 0x00, 0x00, 0x00, 0x57, 0x41, 0x56, 0x45,
56         // fmt chunk. We always write 16-bit samples.
57         0x66, 0x6d, 0x74, 0x20, 0x10, 0x00, 0x00, 0x00, 0x01, 0x00, 0xFF, 0xFF,
58         0xFF, 0xFF, 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x00, 0xFF, 0xFF, 0x10, 0x00,
59         // data chunk
60         0x64, 0x61, 0x74, 0x61, 0xFE, 0xFF, 0xFF, 0x7F};
61     AutoTArray<uint8_t, sizeof(riffHeader)> header;
62     mozilla::ByteWriter<mozilla::LittleEndian> writer(header);
63     static const int CHANNEL_OFFSET = 22;
64     static const int SAMPLE_RATE_OFFSET = 24;
65     static const int BLOCK_ALIGN_OFFSET = 32;
66 
67     mozilla::DebugOnly<bool> rv;
68     // Then number of bytes written in each iteration.
69     uint32_t written = 0;
70     for (size_t i = 0; i != sizeof(riffHeader);) {
71       switch (i) {
72         case CHANNEL_OFFSET:
73           rv = writer.WriteU16(aChannels);
74           written = 2;
75           MOZ_ASSERT(rv);
76           break;
77         case SAMPLE_RATE_OFFSET:
78           rv = writer.WriteU32(aRate);
79           written = 4;
80           MOZ_ASSERT(rv);
81           break;
82         case BLOCK_ALIGN_OFFSET:
83           rv = writer.WriteU16(aChannels * 2);
84           written = 2;
85           MOZ_ASSERT(rv);
86           break;
87         default:
88           // copy from the riffHeader struct above
89           rv = writer.WriteU8(riffHeader[i]);
90           written = 1;
91           MOZ_ASSERT(rv);
92           break;
93       }
94       i += written;
95     }
96     mozilla::Unused << fwrite(header.Elements(), header.Length(), 1, mFile);
97   }
98 
99   template <typename T>
Write(const T * aBuffer,uint32_t aSamples)100   void Write(const T* aBuffer, uint32_t aSamples) {
101     if (!mFile) {
102       return;
103     }
104     WriteDumpFileHelper(aBuffer, aSamples);
105   }
106 
107  private:
WriteDumpFileHelper(const int16_t * aInput,size_t aSamples)108   void WriteDumpFileHelper(const int16_t* aInput, size_t aSamples) {
109     mozilla::Unused << fwrite(aInput, sizeof(int16_t), aSamples, mFile);
110     fflush(mFile);
111   }
112 
WriteDumpFileHelper(const float * aInput,size_t aSamples)113   void WriteDumpFileHelper(const float* aInput, size_t aSamples) {
114     using namespace mozilla;
115 
116     AutoTArray<uint8_t, 1024 * 2> buf;
117     mozilla::ByteWriter<mozilla::LittleEndian> writer(buf);
118     for (uint32_t i = 0; i < aSamples; ++i) {
119       mozilla::DebugOnly<bool> rv =
120           writer.WriteU16(int16_t(aInput[i] * 32767.0f));
121       MOZ_ASSERT(rv);
122     }
123     mozilla::Unused << fwrite(buf.Elements(), buf.Length(), 1, mFile);
124     fflush(mFile);
125   }
126 
127   FILE* mFile = nullptr;
128 };
129 
130 #endif  // WavDumper_h_
131