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