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 "AudioBufferProviderSource" 18 //#define LOG_NDEBUG 0 19 20 #include <cutils/compiler.h> 21 #include <utils/Log.h> 22 #include <media/nbaio/AudioBufferProviderSource.h> 23 24 namespace android { 25 26 AudioBufferProviderSource::AudioBufferProviderSource(AudioBufferProvider *provider, 27 NBAIO_Format format) : 28 NBAIO_Source(format), mProvider(provider), mConsumed(0) 29 { 30 ALOG_ASSERT(provider != NULL); 31 ALOG_ASSERT(format != Format_Invalid); 32 } 33 34 AudioBufferProviderSource::~AudioBufferProviderSource() 35 { 36 if (mBuffer.raw != NULL) { 37 mProvider->releaseBuffer(&mBuffer); 38 } 39 } 40 41 ssize_t AudioBufferProviderSource::availableToRead() 42 { 43 if (CC_UNLIKELY(!mNegotiated)) { 44 return NEGOTIATE; 45 } 46 return mBuffer.raw != NULL ? mBuffer.frameCount - mConsumed : 0; 47 } 48 49 ssize_t AudioBufferProviderSource::read(void *buffer, 50 size_t count, 51 int64_t readPTS) 52 { 53 if (CC_UNLIKELY(!mNegotiated)) { 54 return NEGOTIATE; 55 } 56 if (CC_UNLIKELY(mBuffer.raw == NULL)) { 57 mBuffer.frameCount = count; 58 status_t status = mProvider->getNextBuffer(&mBuffer, readPTS); 59 if (status != OK) { 60 return status == NOT_ENOUGH_DATA ? (ssize_t) WOULD_BLOCK : (ssize_t) status; 61 } 62 ALOG_ASSERT(mBuffer.raw != NULL); 63 // mConsumed is 0 either from constructor or after releaseBuffer() 64 } 65 size_t available = mBuffer.frameCount - mConsumed; 66 if (CC_UNLIKELY(count > available)) { 67 count = available; 68 } 69 // count could be zero, either because count was zero on entry or 70 // available is zero, but both are unlikely so don't check for that 71 memcpy(buffer, (char *) mBuffer.raw + (mConsumed << mBitShift), count << mBitShift); 72 if (CC_UNLIKELY((mConsumed += count) >= mBuffer.frameCount)) { 73 mProvider->releaseBuffer(&mBuffer); 74 mBuffer.raw = NULL; 75 mConsumed = 0; 76 } 77 mFramesRead += count; 78 // For better responsiveness with large values of count, 79 // return a short count rather than continuing with next buffer. 80 // This gives the caller a chance to interpolate other actions. 81 return count; 82 } 83 84 ssize_t AudioBufferProviderSource::readVia(readVia_t via, size_t total, void *user, 85 int64_t readPTS, size_t block) 86 { 87 if (CC_UNLIKELY(!mNegotiated)) { 88 return NEGOTIATE; 89 } 90 if (CC_UNLIKELY(block == 0)) { 91 block = ~0; 92 } 93 for (size_t accumulator = 0; ; ) { 94 ALOG_ASSERT(accumulator <= total); 95 size_t count = total - accumulator; 96 if (CC_UNLIKELY(count == 0)) { 97 return accumulator; 98 } 99 if (CC_LIKELY(count > block)) { 100 count = block; 101 } 102 // 1 <= count <= block 103 if (CC_UNLIKELY(mBuffer.raw == NULL)) { 104 mBuffer.frameCount = count; 105 status_t status = mProvider->getNextBuffer(&mBuffer, readPTS); 106 if (CC_LIKELY(status == OK)) { 107 ALOG_ASSERT(mBuffer.raw != NULL && mBuffer.frameCount <= count); 108 // mConsumed is 0 either from constructor or after releaseBuffer() 109 continue; 110 } 111 // FIXME simplify logic - does the initial count and block checks again for no reason; 112 // don't you just want to fall through to the size_t available line? 113 if (CC_LIKELY(status == NOT_ENOUGH_DATA)) { 114 status = WOULD_BLOCK; 115 } 116 return accumulator > 0 ? accumulator : (ssize_t) status; 117 } 118 size_t available = mBuffer.frameCount - mConsumed; 119 if (CC_UNLIKELY(count > available)) { 120 count = available; 121 } 122 if (CC_LIKELY(count > 0)) { 123 char* readTgt = (char *) mBuffer.raw + (mConsumed << mBitShift); 124 ssize_t ret = via(user, readTgt, count, readPTS); 125 if (CC_UNLIKELY(ret <= 0)) { 126 if (CC_LIKELY(accumulator > 0)) { 127 return accumulator; 128 } 129 return ret; 130 } 131 ALOG_ASSERT((size_t) ret <= count); 132 mFramesRead += ret; 133 accumulator += ret; 134 if (CC_LIKELY((mConsumed += ret) < mBuffer.frameCount)) { 135 continue; 136 } 137 } 138 mProvider->releaseBuffer(&mBuffer); 139 mBuffer.raw = NULL; 140 mConsumed = 0; 141 // don't get next buffer until we really need it 142 } 143 } 144 145 } // namespace android 146
