NBAIO.cpp revision fc7992bd8220824f1404c0c54ac516d9e28b58c2 
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(NBAIO_Format format)
26{
27    switch (format) {
28    case Format_SR44_1_C2_I16:
29    case Format_SR48_C2_I16:
30        return 2 * sizeof(short);
31    case Format_SR44_1_C1_I16:
32    case Format_SR48_C1_I16:
33        return 1 * sizeof(short);
34    case Format_Invalid:
35    default:
36        return 0;
37    }
38}
39
40size_t Format_frameBitShift(NBAIO_Format format)
41{
42    switch (format) {
43    case Format_SR44_1_C2_I16:
44    case Format_SR48_C2_I16:
45        return 2;   // 1 << 2 == 2 * sizeof(short)
46    case Format_SR44_1_C1_I16:
47    case Format_SR48_C1_I16:
48        return 1;   // 1 << 1 == 1 * sizeof(short)
49    case Format_Invalid:
50    default:
51        return 0;
52    }
53}
54
55unsigned Format_sampleRate(NBAIO_Format format)
56{
57    switch (format) {
58    case Format_SR44_1_C1_I16:
59    case Format_SR44_1_C2_I16:
60        return 44100;
61    case Format_SR48_C1_I16:
62    case Format_SR48_C2_I16:
63        return 48000;
64    case Format_Invalid:
65    default:
66        return 0;
67    }
68}
69
70unsigned Format_channelCount(NBAIO_Format format)
71{
72    switch (format) {
73    case Format_SR44_1_C1_I16:
74    case Format_SR48_C1_I16:
75        return 1;
76    case Format_SR44_1_C2_I16:
77    case Format_SR48_C2_I16:
78        return 2;
79    case Format_Invalid:
80    default:
81        return 0;
82    }
83}
84
85NBAIO_Format Format_from_SR_C(unsigned sampleRate, unsigned channelCount)
86{
87    if (sampleRate == 44100 && channelCount == 2) return Format_SR44_1_C2_I16;
88    if (sampleRate == 48000 && channelCount == 2) return Format_SR48_C2_I16;
89    if (sampleRate == 44100 && channelCount == 1) return Format_SR44_1_C1_I16;
90    if (sampleRate == 48000 && channelCount == 1) return Format_SR48_C1_I16;
91    return Format_Invalid;
92}
93
94// This is a default implementation; it is expected that subclasses will optimize this.
95ssize_t NBAIO_Sink::writeVia(writeVia_t via, size_t total, void *user, size_t block)
96{
97    if (!mNegotiated) {
98        return (ssize_t) NEGOTIATE;
99    }
100    static const size_t maxBlock = 32;
101    size_t frameSize = Format_frameSize(mFormat);
102    ALOG_ASSERT(frameSize > 0 && frameSize <= 8);
103    // double guarantees alignment for stack similar to what malloc() gives for heap
104    if (block == 0 || block > maxBlock) {
105        block = maxBlock;
106    }
107    double buffer[((frameSize * block) + sizeof(double) - 1) / sizeof(double)];
108    size_t accumulator = 0;
109    while (accumulator < total) {
110        size_t count = total - accumulator;
111        if (count > block) {
112            count = block;
113        }
114        ssize_t ret = via(user, buffer, count);
115        if (ret > 0) {
116            ALOG_ASSERT((size_t) ret <= count);
117            size_t maxRet = ret;
118            ret = write(buffer, maxRet);
119            if (ret > 0) {
120                ALOG_ASSERT((size_t) ret <= maxRet);
121                accumulator += ret;
122                continue;
123            }
124        }
125        return accumulator > 0 ? accumulator : ret;
126    }
127    return accumulator;
128}
129
130// This is a default implementation; it is expected that subclasses will optimize this.
131ssize_t NBAIO_Source::readVia(readVia_t via, size_t total, void *user,
132                              int64_t readPTS, size_t block)
133{
134    if (!mNegotiated) {
135        return (ssize_t) NEGOTIATE;
136    }
137    static const size_t maxBlock = 32;
138    size_t frameSize = Format_frameSize(mFormat);
139    ALOG_ASSERT(frameSize > 0 && frameSize <= 8);
140    // double guarantees alignment for stack similar to what malloc() gives for heap
141    if (block == 0 || block > maxBlock) {
142        block = maxBlock;
143    }
144    double buffer[((frameSize * block) + sizeof(double) - 1) / sizeof(double)];
145    size_t accumulator = 0;
146    while (accumulator < total) {
147        size_t count = total - accumulator;
148        if (count > block) {
149            count = block;
150        }
151        ssize_t ret = read(buffer, count, readPTS);
152        if (ret > 0) {
153            ALOG_ASSERT((size_t) ret <= count);
154            size_t maxRet = ret;
155            ret = via(user, buffer, maxRet, readPTS);
156            if (ret > 0) {
157                ALOG_ASSERT((size_t) ret <= maxRet);
158                accumulator += ret;
159                continue;
160            }
161        }
162        return accumulator > 0 ? accumulator : ret;
163    }
164    return accumulator;
165}
166
167// Default implementation that only accepts my mFormat
168ssize_t NBAIO_Port::negotiate(const NBAIO_Format offers[], size_t numOffers,
169                                  NBAIO_Format counterOffers[], size_t& numCounterOffers)
170{
171    ALOGV("negotiate offers=%p numOffers=%u countersOffers=%p numCounterOffers=%u",
172            offers, numOffers, counterOffers, numCounterOffers);
173    if (mFormat != Format_Invalid) {
174        for (size_t i = 0; i < numOffers; ++i) {
175            if (offers[i] == mFormat) {
176                mNegotiated = true;
177                return i;
178            }
179        }
180        if (numCounterOffers > 0) {
181            counterOffers[0] = mFormat;
182        }
183        numCounterOffers = 1;
184    } else {
185        numCounterOffers = 0;
186    }
187    return (ssize_t) NEGOTIATE;
188}
189
190}   // namespace android
191