1 /* ScummVM - Graphic Adventure Engine
2 *
3 * ScummVM is the legal property of its developers, whose names
4 * are too numerous to list here. Please refer to the COPYRIGHT
5 * file distributed with this source distribution.
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version 2
10 * of the License, or (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
20 *
21 */
22
23 #include "scumm/cdda.h"
24 #include "common/stream.h"
25 #include "audio/audiostream.h"
26
27 namespace Scumm {
28
29
30 #pragma mark -
31 #pragma mark --- CDDA stream ---
32 #pragma mark -
33
34 #define START_OF_CDDA_DATA 800
35 #define BLOCK_SIZE 1177
36
37 class CDDAStream : public Audio::SeekableAudioStream {
38 private:
39 Common::SeekableReadStream *_stream;
40 DisposeAfterUse::Flag _disposeAfterUse;
41 byte _shiftLeft;
42 byte _shiftRight;
43 uint32 _pos;
44 Audio::Timestamp _length;
45
46 public:
47 CDDAStream(Common::SeekableReadStream *stream, DisposeAfterUse::Flag disposeAfterUse);
48 ~CDDAStream() override;
49
50 int readBuffer(int16 *buffer, const int numSamples) override;
isStereo() const51 bool isStereo() const override { return true; }
getRate() const52 int getRate() const override { return 44100; }
endOfData() const53 bool endOfData() const override { return _stream->eos(); }
54 bool seek(const Audio::Timestamp &where) override;
getLength() const55 Audio::Timestamp getLength() const override { return _length; }
56 };
57
CDDAStream(Common::SeekableReadStream * stream,DisposeAfterUse::Flag disposeAfterUse)58 CDDAStream::CDDAStream(Common::SeekableReadStream *stream, DisposeAfterUse::Flag disposeAfterUse) :
59 _stream(stream), _disposeAfterUse(disposeAfterUse), _pos(START_OF_CDDA_DATA) {
60 _stream->seek(START_OF_CDDA_DATA, SEEK_SET);
61 // The total size of CDDA.SOU is 289,808,802 bytes or (289808802 - 800) / 1177 = 246226 blocks
62 // We also deduct the shift values to return the correct length
63 uint32 blocks = (_stream->size() - START_OF_CDDA_DATA) / BLOCK_SIZE;
64 _length = Audio::Timestamp(0, (_stream->size() - START_OF_CDDA_DATA - blocks) / (isStereo() ? 2 : 1), getRate());
65 }
66
~CDDAStream()67 CDDAStream::~CDDAStream() {
68 if (_disposeAfterUse == DisposeAfterUse::YES)
69 delete _stream;
70 }
71
seek(const Audio::Timestamp & where)72 bool CDDAStream::seek(const Audio::Timestamp &where) {
73 const uint32 seekSample = convertTimeToStreamPos(where, getRate(), isStereo()).totalNumberOfFrames();
74 uint32 blocks = seekSample / 1176;
75
76 // Before seeking, read the shift values from the beginning of that block
77 _stream->seek(START_OF_CDDA_DATA + blocks * BLOCK_SIZE, SEEK_SET);
78 byte shiftVal = _stream->readByte();
79 _shiftLeft = shiftVal >> 4;
80 _shiftRight = shiftVal & 0x0F;
81
82 _pos = START_OF_CDDA_DATA + blocks + seekSample;
83 return _stream->seek(_pos, SEEK_SET);
84 }
85
readBuffer(int16 * buffer,const int numSamples)86 int CDDAStream::readBuffer(int16 *buffer, const int numSamples) {
87 int samples;
88
89 for (samples = 0 ; samples < numSamples && !_stream->eos() ; ) {
90 if (!((_pos - START_OF_CDDA_DATA) % BLOCK_SIZE)) {
91 byte shiftVal = _stream->readByte();
92 _shiftLeft = shiftVal >> 4;
93 _shiftRight = shiftVal & 0x0F;
94 _pos++;
95 }
96 buffer[samples++] = _stream->readSByte() << _shiftLeft;
97 buffer[samples++] = _stream->readSByte() << _shiftRight;
98 _pos += 2;
99 }
100 return samples;
101 }
102
103 #pragma mark -
104 #pragma mark --- CDDA factory functions ---
105 #pragma mark -
106
makeCDDAStream(Common::SeekableReadStream * stream,DisposeAfterUse::Flag disposeAfterUse)107 Audio::SeekableAudioStream *makeCDDAStream(
108 Common::SeekableReadStream *stream,
109 DisposeAfterUse::Flag disposeAfterUse) {
110 Audio::SeekableAudioStream *s = new CDDAStream(stream, disposeAfterUse);
111 if (s && s->endOfData()) {
112 delete s;
113 return 0;
114 } else {
115 return s;
116 }
117 return 0;
118 }
119
120 } // End of namespace Scumm
121