NBAIO.cpp revision 2b7b910f4b417ab3930379298f538d0dfc857e88 
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
31int 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    // FIXME must return -1 for non-power of 2
37}
38
39const NBAIO_Format Format_Invalid = { 0, 0, AUDIO_FORMAT_INVALID, 0 };
40
41enum {
42    Format_SR_8000,
43    Format_SR_11025,
44    Format_SR_16000,
45    Format_SR_22050,
46    Format_SR_24000,
47    Format_SR_32000,
48    Format_SR_44100,
49    Format_SR_48000,
50    Format_SR_Mask = 7
51};
52
53enum {
54    Format_C_1 = 0x08,
55    Format_C_2 = 0x10,
56    Format_C_Mask = 0x18
57};
58
59unsigned Format_sampleRate(const NBAIO_Format& format)
60{
61    if (!Format_isValid(format)) {
62        return 0;
63    }
64    return format.mSampleRate;
65}
66
67unsigned Format_channelCount(const NBAIO_Format& format)
68{
69    if (!Format_isValid(format)) {
70        return 0;
71    }
72    return format.mChannelCount;
73}
74
75NBAIO_Format Format_from_SR_C(unsigned sampleRate, unsigned channelCount,
76        audio_format_t format)
77{
78    if (sampleRate == 0 || channelCount == 0 || !audio_is_valid_format(format)) {
79        return Format_Invalid;
80    }
81    NBAIO_Format ret;
82    ret.mSampleRate = sampleRate;
83    ret.mChannelCount = channelCount;
84    ret.mFormat = format;
85    ret.mFrameSize = audio_is_linear_pcm(format) ?
86            channelCount * audio_bytes_per_sample(format) : sizeof(uint8_t);
87    return ret;
88}
89
90// This is a default implementation; it is expected that subclasses will optimize this.
91ssize_t NBAIO_Sink::writeVia(writeVia_t via, size_t total, void *user, size_t block)
92{
93    if (!mNegotiated) {
94        return (ssize_t) NEGOTIATE;
95    }
96    static const size_t maxBlock = 32;
97    size_t frameSize = Format_frameSize(mFormat);
98    ALOG_ASSERT(frameSize > 0 && frameSize <= 8);
99    // double guarantees alignment for stack similar to what malloc() gives for heap
100    if (block == 0 || block > maxBlock) {
101        block = maxBlock;
102    }
103    double buffer[((frameSize * block) + sizeof(double) - 1) / sizeof(double)];
104    size_t accumulator = 0;
105    while (accumulator < total) {
106        size_t count = total - accumulator;
107        if (count > block) {
108            count = block;
109        }
110        ssize_t ret = via(user, buffer, count);
111        if (ret > 0) {
112            ALOG_ASSERT((size_t) ret <= count);
113            size_t maxRet = ret;
114            ret = write(buffer, maxRet);
115            if (ret > 0) {
116                ALOG_ASSERT((size_t) ret <= maxRet);
117                accumulator += ret;
118                continue;
119            }
120        }
121        return accumulator > 0 ? accumulator : ret;
122    }
123    return accumulator;
124}
125
126// This is a default implementation; it is expected that subclasses will optimize this.
127ssize_t NBAIO_Source::readVia(readVia_t via, size_t total, void *user,
128                              int64_t readPTS, size_t block)
129{
130    if (!mNegotiated) {
131        return (ssize_t) NEGOTIATE;
132    }
133    static const size_t maxBlock = 32;
134    size_t frameSize = Format_frameSize(mFormat);
135    ALOG_ASSERT(frameSize > 0 && frameSize <= 8);
136    // double guarantees alignment for stack similar to what malloc() gives for heap
137    if (block == 0 || block > maxBlock) {
138        block = maxBlock;
139    }
140    double buffer[((frameSize * block) + sizeof(double) - 1) / sizeof(double)];
141    size_t accumulator = 0;
142    while (accumulator < total) {
143        size_t count = total - accumulator;
144        if (count > block) {
145            count = block;
146        }
147        ssize_t ret = read(buffer, count, readPTS);
148        if (ret > 0) {
149            ALOG_ASSERT((size_t) ret <= count);
150            size_t maxRet = ret;
151            ret = via(user, buffer, maxRet, readPTS);
152            if (ret > 0) {
153                ALOG_ASSERT((size_t) ret <= maxRet);
154                accumulator += ret;
155                continue;
156            }
157        }
158        return accumulator > 0 ? accumulator : ret;
159    }
160    return accumulator;
161}
162
163// Default implementation that only accepts my mFormat
164ssize_t NBAIO_Port::negotiate(const NBAIO_Format offers[], size_t numOffers,
165                                  NBAIO_Format counterOffers[], size_t& numCounterOffers)
166{
167    ALOGV("negotiate offers=%p numOffers=%u countersOffers=%p numCounterOffers=%u",
168            offers, numOffers, counterOffers, numCounterOffers);
169    if (Format_isValid(mFormat)) {
170        for (size_t i = 0; i < numOffers; ++i) {
171            if (Format_isEqual(offers[i], mFormat)) {
172                mNegotiated = true;
173                return i;
174            }
175        }
176        if (numCounterOffers > 0) {
177            counterOffers[0] = mFormat;
178        }
179        numCounterOffers = 1;
180    } else {
181        numCounterOffers = 0;
182    }
183    return (ssize_t) NEGOTIATE;
184}
185
186bool Format_isValid(const NBAIO_Format& format)
187{
188    return format.mSampleRate != 0 && format.mChannelCount != 0 &&
189            format.mFormat != AUDIO_FORMAT_INVALID && format.mFrameSize != 0;
190}
191
192bool Format_isEqual(const NBAIO_Format& format1, const NBAIO_Format& format2)
193{
194    return format1.mSampleRate == format2.mSampleRate &&
195            format1.mChannelCount == format2.mChannelCount && format1.mFormat == format2.mFormat &&
196            format1.mFrameSize == format2.mFrameSize;
197}
198
199}   // namespace android
200