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 "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, size_t count) 50 { 51 if (CC_UNLIKELY(!mNegotiated)) { 52 return NEGOTIATE; 53 } 54 if (CC_UNLIKELY(mBuffer.raw == NULL)) { 55 mBuffer.frameCount = count; 56 status_t status = mProvider->getNextBuffer(&mBuffer, AudioBufferProvider::kInvalidPTS); 57 if (status != OK) { 58 return status == NOT_ENOUGH_DATA ? (ssize_t) WOULD_BLOCK : (ssize_t) status; 59 } 60 ALOG_ASSERT(mBuffer.raw != NULL); 61 // mConsumed is 0 either from constructor or after releaseBuffer() 62 } 63 size_t available = mBuffer.frameCount - mConsumed; 64 if (CC_UNLIKELY(count > available)) { 65 count = available; 66 } 67 // count could be zero, either because count was zero on entry or 68 // available is zero, but both are unlikely so don't check for that 69 memcpy(buffer, (char *) mBuffer.raw + (mConsumed << mBitShift), count << mBitShift); 70 if (CC_UNLIKELY((mConsumed += count) >= mBuffer.frameCount)) { 71 mProvider->releaseBuffer(&mBuffer); 72 mBuffer.raw = NULL; 73 mConsumed = 0; 74 } 75 mFramesRead += count; 76 // For better responsiveness with large values of count, 77 // return a short count rather than continuing with next buffer. 78 // This gives the caller a chance to interpolate other actions. 79 return count; 80 } 81 82 ssize_t AudioBufferProviderSource::readVia(readVia_t via, size_t total, void *user, size_t block) 83 { 84 if (CC_UNLIKELY(!mNegotiated)) { 85 return NEGOTIATE; 86 } 87 if (CC_UNLIKELY(block == 0)) { 88 block = ~0; 89 } 90 for (size_t accumulator = 0; ; ) { 91 ALOG_ASSERT(accumulator <= total); 92 size_t count = total - accumulator; 93 if (CC_UNLIKELY(count == 0)) { 94 return accumulator; 95 } 96 if (CC_LIKELY(count > block)) { 97 count = block; 98 } 99 // 1 <= count <= block 100 if (CC_UNLIKELY(mBuffer.raw == NULL)) { 101 mBuffer.frameCount = count; 102 status_t status = mProvider->getNextBuffer(&mBuffer, AudioBufferProvider::kInvalidPTS); 103 if (CC_LIKELY(status == OK)) { 104 ALOG_ASSERT(mBuffer.raw != NULL && mBuffer.frameCount <= count); 105 // mConsumed is 0 either from constructor or after releaseBuffer() 106 continue; 107 } 108 // FIXME simplify logic - does the initial count and block checks again for no reason; 109 // don't you just want to fall through to the size_t available line? 110 if (CC_LIKELY(status == NOT_ENOUGH_DATA)) { 111 status = WOULD_BLOCK; 112 } 113 return accumulator > 0 ? accumulator : (ssize_t) status; 114 } 115 size_t available = mBuffer.frameCount - mConsumed; 116 if (CC_UNLIKELY(count > available)) { 117 count = available; 118 } 119 if (CC_LIKELY(count > 0)) { 120 ssize_t ret = via(user, (char *) mBuffer.raw + (mConsumed << mBitShift), count); 121 if (CC_UNLIKELY(ret <= 0)) { 122 if (CC_LIKELY(accumulator > 0)) { 123 return accumulator; 124 } 125 return ret; 126 } 127 ALOG_ASSERT((size_t) ret <= count); 128 mFramesRead += ret; 129 accumulator += ret; 130 if (CC_LIKELY((mConsumed += ret) < mBuffer.frameCount)) { 131 continue; 132 } 133 } 134 mProvider->releaseBuffer(&mBuffer); 135 mBuffer.raw = NULL; 136 mConsumed = 0; 137 // don't get next buffer until we really need it 138 } 139 } 140 141 } // namespace android 142
