NBAIO.cpp revision 1ec712f180072a7eb2131be09862921ae62dc2b4 
1/*
2 * Copyright (C) 2012 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#define LOG_TAG "NBAIO"
18//#define LOG_NDEBUG 0
19
20#include <utils/Log.h>
21#include <media/nbaio/NBAIO.h>
22
23namespace android {
24
25size_t Format_frameSize(const NBAIO_Format& format)
26{
27    // FIXME The sample format is hard-coded to AUDIO_FORMAT_PCM_16_BIT
28    return Format_channelCount(format) * sizeof(short);
29}
30
31size_t Format_frameBitShift(const NBAIO_Format& format)
32{
33    // FIXME The sample format is hard-coded to AUDIO_FORMAT_PCM_16_BIT
34    // sizeof(short) == 2, so frame size == 1 << channels
35    return Format_channelCount(format);
36}
37
38const NBAIO_Format Format_Invalid = { 0 };
39
40enum {
41    Format_SR_8000,
42    Format_SR_11025,
43    Format_SR_16000,
44    Format_SR_22050,
45    Format_SR_24000,
46    Format_SR_32000,
47    Format_SR_44100,
48    Format_SR_48000,
49    Format_SR_Mask = 7
50};
51
52enum {
53    Format_C_1 = 0x08,
54    Format_C_2 = 0x10,
55    Format_C_Mask = 0x18
56};
57
58unsigned Format_sampleRate(const NBAIO_Format& format)
59{
60    if (!Format_isValid(format)) {
61        return 0;
62    }
63    switch (format.mPacked & Format_SR_Mask) {
64    case Format_SR_8000:
65        return 8000;
66    case Format_SR_11025:
67        return 11025;
68    case Format_SR_16000:
69        return 16000;
70    case Format_SR_22050:
71        return 22050;
72    case Format_SR_24000:
73        return 24000;
74    case Format_SR_32000:
75        return 32000;
76    case Format_SR_44100:
77        return 44100;
78    case Format_SR_48000:
79        return 48000;
80    default:
81        return 0;
82    }
83}
84
85unsigned Format_channelCount(const NBAIO_Format& format)
86{
87    if (!Format_isValid(format)) {
88        return 0;
89    }
90    switch (format.mPacked & Format_C_Mask) {
91    case Format_C_1:
92        return 1;
93    case Format_C_2:
94        return 2;
95    default:
96        return 0;
97    }
98}
99
100NBAIO_Format Format_from_SR_C(unsigned sampleRate, unsigned channelCount)
101{
102    unsigned format;
103    switch (sampleRate) {
104    case 8000:
105        format = Format_SR_8000;
106        break;
107    case 11025:
108        format = Format_SR_11025;
109        break;
110    case 16000:
111        format = Format_SR_16000;
112        break;
113    case 22050:
114        format = Format_SR_22050;
115        break;
116    case 24000:
117        format = Format_SR_24000;
118        break;
119    case 32000:
120        format = Format_SR_32000;
121        break;
122    case 44100:
123        format = Format_SR_44100;
124        break;
125    case 48000:
126        format = Format_SR_48000;
127        break;
128    default:
129        return Format_Invalid;
130    }
131    switch (channelCount) {
132    case 1:
133        format |= Format_C_1;
134        break;
135    case 2:
136        format |= Format_C_2;
137        break;
138    default:
139        return Format_Invalid;
140    }
141    NBAIO_Format ret;
142    ret.mPacked = format;
143    return ret;
144}
145
146// This is a default implementation; it is expected that subclasses will optimize this.
147ssize_t NBAIO_Sink::writeVia(writeVia_t via, size_t total, void *user, size_t block)
148{
149    if (!mNegotiated) {
150        return (ssize_t) NEGOTIATE;
151    }
152    static const size_t maxBlock = 32;
153    size_t frameSize = Format_frameSize(mFormat);
154    ALOG_ASSERT(frameSize > 0 && frameSize <= 8);
155    // double guarantees alignment for stack similar to what malloc() gives for heap
156    if (block == 0 || block > maxBlock) {
157        block = maxBlock;
158    }
159    double buffer[((frameSize * block) + sizeof(double) - 1) / sizeof(double)];
160    size_t accumulator = 0;
161    while (accumulator < total) {
162        size_t count = total - accumulator;
163        if (count > block) {
164            count = block;
165        }
166        ssize_t ret = via(user, buffer, count);
167        if (ret > 0) {
168            ALOG_ASSERT((size_t) ret <= count);
169            size_t maxRet = ret;
170            ret = write(buffer, maxRet);
171            if (ret > 0) {
172                ALOG_ASSERT((size_t) ret <= maxRet);
173                accumulator += ret;
174                continue;
175            }
176        }
177        return accumulator > 0 ? accumulator : ret;
178    }
179    return accumulator;
180}
181
182// This is a default implementation; it is expected that subclasses will optimize this.
183ssize_t NBAIO_Source::readVia(readVia_t via, size_t total, void *user,
184                              int64_t readPTS, size_t block)
185{
186    if (!mNegotiated) {
187        return (ssize_t) NEGOTIATE;
188    }
189    static const size_t maxBlock = 32;
190    size_t frameSize = Format_frameSize(mFormat);
191    ALOG_ASSERT(frameSize > 0 && frameSize <= 8);
192    // double guarantees alignment for stack similar to what malloc() gives for heap
193    if (block == 0 || block > maxBlock) {
194        block = maxBlock;
195    }
196    double buffer[((frameSize * block) + sizeof(double) - 1) / sizeof(double)];
197    size_t accumulator = 0;
198    while (accumulator < total) {
199        size_t count = total - accumulator;
200        if (count > block) {
201            count = block;
202        }
203        ssize_t ret = read(buffer, count, readPTS);
204        if (ret > 0) {
205            ALOG_ASSERT((size_t) ret <= count);
206            size_t maxRet = ret;
207            ret = via(user, buffer, maxRet, readPTS);
208            if (ret > 0) {
209                ALOG_ASSERT((size_t) ret <= maxRet);
210                accumulator += ret;
211                continue;
212            }
213        }
214        return accumulator > 0 ? accumulator : ret;
215    }
216    return accumulator;
217}
218
219// Default implementation that only accepts my mFormat
220ssize_t NBAIO_Port::negotiate(const NBAIO_Format offers[], size_t numOffers,
221                                  NBAIO_Format counterOffers[], size_t& numCounterOffers)
222{
223    ALOGV("negotiate offers=%p numOffers=%u countersOffers=%p numCounterOffers=%u",
224            offers, numOffers, counterOffers, numCounterOffers);
225    if (Format_isValid(mFormat)) {
226        for (size_t i = 0; i < numOffers; ++i) {
227            if (Format_isEqual(offers[i], mFormat)) {
228                mNegotiated = true;
229                return i;
230            }
231        }
232        if (numCounterOffers > 0) {
233            counterOffers[0] = mFormat;
234        }
235        numCounterOffers = 1;
236    } else {
237        numCounterOffers = 0;
238    }
239    return (ssize_t) NEGOTIATE;
240}
241
242bool Format_isValid(const NBAIO_Format& format)
243{
244    return format.mPacked != Format_Invalid.mPacked;
245}
246
247bool Format_isEqual(const NBAIO_Format& format1, const NBAIO_Format& format2)
248{
249    return format1.mPacked == format2.mPacked;
250}
251
252}   // namespace android
253