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80 lines
2.2 KiB
80 lines
2.2 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 <log/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(headerLength) // minimum
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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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