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79 lines
2.1 KiB
79 lines
2.1 KiB
/* |
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* Copyright 2014, The Android Open Source Project |
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* |
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* Licensed under the Apache License, Version 2.0 (the "License"); |
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* you may not use this file except in compliance with the License. |
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* You may obtain a copy of the License at |
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* |
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* http://www.apache.org/licenses/LICENSE-2.0 |
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* |
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* Unless required by applicable law or agreed to in writing, software |
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* distributed under the License is distributed on an "AS IS" BASIS, |
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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* See the License for the specific language governing permissions and |
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* limitations under the License. |
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*/ |
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#define LOG_TAG "AudioSPDIF" |
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#include <string.h> |
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#include <assert.h> |
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#include <utils/Log.h> |
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#include <audio_utils/spdif/FrameScanner.h> |
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namespace android { |
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FrameScanner::FrameScanner(int dataType, |
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const uint8_t *syncBytes, |
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uint32_t syncLength, |
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uint32_t headerLength) |
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: mBytesSkipped(0) |
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, mSyncBytes(syncBytes) |
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, mSyncLength(syncLength) |
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, mHeaderLength(headerLength) |
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, mCursor(0) |
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, mFormatDumpCount(0) |
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, mSampleRate(0) |
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, mRateMultiplier(1) |
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, mFrameSizeBytes(0) |
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, mDataType(dataType) |
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, mDataTypeInfo(0) |
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{ |
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} |
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FrameScanner::~FrameScanner() |
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{ |
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} |
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// State machine that scans for headers in a byte stream. |
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// @return true if we have detected a complete and valid header. |
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bool FrameScanner::scan(uint8_t byte) |
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{ |
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bool result = false; |
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ALOGV("FrameScanner: byte = 0x%02X, mCursor = %d", byte, mCursor); |
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assert(mCursor < sizeof(mHeaderBuffer)); |
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if (mCursor < mSyncLength) { |
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// match sync word |
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if (byte == mSyncBytes[mCursor]) { |
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mHeaderBuffer[mCursor++] = byte; |
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} else { |
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mBytesSkipped += 1; // skip unsynchronized data |
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mCursor = 0; |
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} |
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} else if (mCursor < mHeaderLength) { |
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// gather header for parsing |
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mHeaderBuffer[mCursor++] = byte; |
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if (mCursor >= mHeaderLength) { |
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if (parseHeader()) { |
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result = true; |
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} else { |
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ALOGE("FrameScanner: ERROR - parseHeader() failed."); |
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} |
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mCursor = 0; |
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} |
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} |
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return result; |
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} |
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} // namespace android
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