jt2594838 commented on code in PR #560: URL: https://github.com/apache/tsfile/pull/560#discussion_r2247652833
########## java/tsfile/src/main/java/org/apache/tsfile/common/bitStream/BitInputStream.java: ########## @@ -0,0 +1,264 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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. + */ + +package org.apache.tsfile.common.bitStream; + +import java.io.EOFException; +import java.io.IOException; +import java.io.InputStream; + +/** A stream for reading individual bits or groups of bits from an InputStream. */ +public class BitInputStream extends BitStream { + + protected InputStream in; + protected int buffer; + protected int bufferBitCount; + protected final long totalBits; // Total valid bits + protected long bitsRead = 0; // Number of bits read so far + + protected int markedBuffer = 0; + protected int markedBufferBitCount = 0; + protected long markedBitsRead = 0; + + /** + * Constructs a BitInputStream with a given InputStream and total number of valid bits. + * + * @param in the underlying InputStream + * @param totalBits the total number of valid bits to read + */ + public BitInputStream(InputStream in, long totalBits) { + this.in = in; + this.totalBits = totalBits; + this.bufferBitCount = 0; + } + + /** + * Reads an integer value using the specified number of bits. If fewer bits are available, only + * the available bits are returned. + * + * @param numBits the number of bits to read (≤ 32) + * @return an integer whose lower bits contain the read value + * @throws EOFException if no data is available to read + * @throws IOException if an I/O error occurs + */ + public int readInt(int numBits) throws IOException { + if (availableBits() <= 0) { + throw new EOFException(); + } + + bitsRead += numBits; + int result = 0; + boolean hasReadData = false; + + while (numBits > 0) { + if (bufferBitCount == 0) { + buffer = in.read(); + if (buffer < 0) { + if (!hasReadData) { + throw new EOFException(); + } + return result; + } + bufferBitCount = BITS_PER_BYTE; + } + + if (bufferBitCount > numBits) { + result = ((buffer >> (bufferBitCount - numBits)) & MASKS[numBits]) | result; + bufferBitCount -= numBits; + numBits = 0; + } else { + result = ((buffer & MASKS[bufferBitCount]) << (numBits - bufferBitCount)) | result; + numBits -= bufferBitCount; + bufferBitCount = 0; + } + + hasReadData = true; + } + + return result; + } + + /** + * Reads a long value using the specified number of bits. + * + * @param numBits the number of bits to read (0 to 64) + * @return a long value containing the read bits + * @throws EOFException if no data is available to read + * @throws IOException if an I/O error occurs + */ + public long readLong(int numBits) throws IOException { + if (availableBits() <= 0) { + throw new EOFException(); + } + bitsRead += numBits; + if (numBits > 64 || numBits < 0) { + throw new IllegalArgumentException("numBits must be between 0 and 64"); + } + + long result = 0; + boolean hasReadData = false; + + while (numBits > 0) { + if (bufferBitCount == 0) { + buffer = in.read(); + if (buffer < 0) { + if (!hasReadData) { + throw new EOFException(); + } + return result; + } + bufferBitCount = BITS_PER_BYTE; + } + + if (bufferBitCount > numBits) { + int shift = bufferBitCount - numBits; + result = (result << numBits) | ((buffer >> shift) & MASKS[numBits]); + bufferBitCount -= numBits; + buffer &= MASKS[bufferBitCount]; + numBits = 0; + } else { + result = (result << bufferBitCount) | (buffer & MASKS[bufferBitCount]); + numBits -= bufferBitCount; + bufferBitCount = 0; + } + + hasReadData = true; + } + + return result; + } + + public static int readVarInt(BitInputStream in) throws IOException { + int result = 0; + int shift = 0; + + while (true) { + int chunk = in.readInt(7); + boolean hasNext = in.readBit(); + result |= chunk << shift; + if (!hasNext) break; Review Comment: Mind the code style (if with only one line still should use `{}`) ########## java/tsfile/src/main/java/org/apache/tsfile/common/bitStream/BitInputStream.java: ########## @@ -0,0 +1,264 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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. + */ + +package org.apache.tsfile.common.bitStream; + +import java.io.EOFException; +import java.io.IOException; +import java.io.InputStream; + +/** A stream for reading individual bits or groups of bits from an InputStream. */ +public class BitInputStream extends BitStream { + + protected InputStream in; + protected int buffer; + protected int bufferBitCount; + protected final long totalBits; // Total valid bits + protected long bitsRead = 0; // Number of bits read so far + + protected int markedBuffer = 0; + protected int markedBufferBitCount = 0; + protected long markedBitsRead = 0; + + /** + * Constructs a BitInputStream with a given InputStream and total number of valid bits. + * + * @param in the underlying InputStream + * @param totalBits the total number of valid bits to read + */ + public BitInputStream(InputStream in, long totalBits) { + this.in = in; + this.totalBits = totalBits; + this.bufferBitCount = 0; + } + + /** + * Reads an integer value using the specified number of bits. If fewer bits are available, only + * the available bits are returned. + * + * @param numBits the number of bits to read (≤ 32) + * @return an integer whose lower bits contain the read value + * @throws EOFException if no data is available to read + * @throws IOException if an I/O error occurs + */ + public int readInt(int numBits) throws IOException { + if (availableBits() <= 0) { + throw new EOFException(); + } + + bitsRead += numBits; + int result = 0; + boolean hasReadData = false; + + while (numBits > 0) { + if (bufferBitCount == 0) { + buffer = in.read(); + if (buffer < 0) { + if (!hasReadData) { + throw new EOFException(); + } + return result; + } + bufferBitCount = BITS_PER_BYTE; + } + + if (bufferBitCount > numBits) { + result = ((buffer >> (bufferBitCount - numBits)) & MASKS[numBits]) | result; + bufferBitCount -= numBits; + numBits = 0; + } else { + result = ((buffer & MASKS[bufferBitCount]) << (numBits - bufferBitCount)) | result; + numBits -= bufferBitCount; + bufferBitCount = 0; + } + + hasReadData = true; + } + + return result; + } + + /** + * Reads a long value using the specified number of bits. + * + * @param numBits the number of bits to read (0 to 64) + * @return a long value containing the read bits + * @throws EOFException if no data is available to read + * @throws IOException if an I/O error occurs + */ + public long readLong(int numBits) throws IOException { + if (availableBits() <= 0) { + throw new EOFException(); + } + bitsRead += numBits; + if (numBits > 64 || numBits < 0) { + throw new IllegalArgumentException("numBits must be between 0 and 64"); + } Review Comment: Add this for readInt()? ########## java/tsfile/src/main/java/org/apache/tsfile/encoding/decoder/CamelDecoder.java: ########## @@ -0,0 +1,273 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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. + */ + +package org.apache.tsfile.encoding.decoder; + +import org.apache.tsfile.common.bitStream.BitInputStream; +import org.apache.tsfile.common.bitStream.ByteBufferBackedInputStream; +import org.apache.tsfile.exception.encoding.TsFileDecodingException; +import org.apache.tsfile.file.metadata.enums.TSEncoding; +import org.apache.tsfile.utils.ReadWriteForEncodingUtils; + +import java.io.IOException; +import java.io.InputStream; +import java.nio.ByteBuffer; +import java.util.LinkedList; +import java.util.List; + +public class CamelDecoder extends Decoder { + // === Constants for decoding === + private static final int BITS_FOR_SIGN = 1; + private static final int BITS_FOR_TYPE = 1; + private static final int BITS_FOR_FIRST_VALUE = 64; + private static final int BITS_FOR_LEADING_ZEROS = 6; + private static final int BITS_FOR_SIGNIFICANT_BITS = 6; + private static final int BITS_FOR_DECIMAL_COUNT = 4; + private static final int DOUBLE_TOTAL_BITS = 64; + private static final int DOUBLE_MANTISSA_BITS = 52; + private static final int DECIMAL_MAX_COUNT = 15; + + // === Camel state === + private long previousValue = 0; + private boolean isFirst = true; + private long storedVal = 0; + + // === Precomputed tables === + public static final long[] powers = new long[DECIMAL_MAX_COUNT]; + public static final long[] threshold = new long[DECIMAL_MAX_COUNT]; + public static final int[] mValueBits = new int[DECIMAL_MAX_COUNT]; + + static { + for (int l = 1; l <= DECIMAL_MAX_COUNT; l++) { + int idx = l - 1; + powers[idx] = (long) Math.pow(10, l); + long divisor = 1L << l; + threshold[idx] = powers[idx] / divisor; + mValueBits[idx] = (int) Math.ceil(Math.log(threshold[idx]) / Math.log(2)); + } + } + + private BitInputStream in; + private final GorillaDecoder gorillaDecoder; + + public CamelDecoder(InputStream inputStream, long totalBits) { + super(TSEncoding.CAMEL); + // Initialize bit-level reader and nested Gorilla decoder + this.in = new BitInputStream(inputStream, totalBits); + this.gorillaDecoder = new GorillaDecoder(); + } + + public CamelDecoder() { + super(TSEncoding.CAMEL); + this.gorillaDecoder = new GorillaDecoder(); + } + + @Override + public boolean hasNext(ByteBuffer buffer) throws IOException { + if (cacheIndex < valueCache.size()) { + return true; + } + if (in != null && in.availableBits() > 0) { + return true; + } + return buffer.hasRemaining(); + } + + @Override + public void reset() { + this.in = null; + this.isFirst = true; + this.previousValue = 0L; + this.storedVal = 0L; + this.gorillaDecoder.leadingZeros = Integer.MAX_VALUE; + this.gorillaDecoder.trailingZeros = 0; + } + + // Cache for batch decoding + private List<Double> valueCache = new LinkedList<>(); + private int cacheIndex = 0; + + @Override + public double readDouble(ByteBuffer buffer) { + try { + // If the current block has been fully read, load the next block + if (cacheIndex >= valueCache.size()) { + // If no BitInputStream is available or all bits have been consumed + if (in == null || in.availableBits() == 0) { + if (!buffer.hasRemaining()) { + throw new TsFileDecodingException("No more data to decode"); + } + + ByteBuffer slice = buffer.slice(); // Keep this + ByteBufferBackedInputStream bais = new ByteBufferBackedInputStream(slice); + + // Read the number of bits in the current block + int blockBits = ReadWriteForEncodingUtils.readVarInt(bais); + this.in = new BitInputStream(bais, blockBits); + + // Reset decoder state for the new block + this.isFirst = true; + this.storedVal = 0L; + this.previousValue = 0L; + this.gorillaDecoder.leadingZeros = Integer.MAX_VALUE; + this.gorillaDecoder.trailingZeros = 0; + + // Decode the entire block into a temporary value cache + List<Double> newValues = getValues(); + if (newValues.isEmpty()) { + throw new TsFileDecodingException("Unexpected empty block"); + } + valueCache = newValues; + cacheIndex = 0; + + // Advance the buffer position by the number of bytes consumed + // int consumed = temp.length - bais.available(); + int consumed = bais.getConsumed(); + + buffer.position(buffer.position() + consumed); + } + } + + // Return the next decoded value from the cache + return valueCache.get(cacheIndex++); + } catch (IOException e) { + throw new TsFileDecodingException(e.getMessage()); + } + } + + /** Nested class to handle fallback encoding (Gorilla) for double values. */ + public class GorillaDecoder { + private int leadingZeros = Integer.MAX_VALUE; + private int trailingZeros = 0; + + /** Decode next value using Gorilla algorithm. */ + public double decode(BitInputStream in) throws IOException { + if (isFirst) { + previousValue = in.readLong(BITS_FOR_FIRST_VALUE); + isFirst = false; + return Double.longBitsToDouble(previousValue); + } + + boolean controlBit = in.readBit(); + if (!controlBit) { + return Double.longBitsToDouble(previousValue); + } + + boolean reuseBlock = !in.readBit(); + long xor; + if (reuseBlock) { + int sigBits = DOUBLE_TOTAL_BITS - leadingZeros - trailingZeros; + if (sigBits == 0) { + return Double.longBitsToDouble(previousValue); + } + xor = in.readLong(sigBits) << trailingZeros; + } else { + leadingZeros = in.readInt(BITS_FOR_LEADING_ZEROS); + int sigBits = in.readInt(BITS_FOR_SIGNIFICANT_BITS) + 1; + trailingZeros = DOUBLE_TOTAL_BITS - leadingZeros - sigBits; + xor = in.readLong(sigBits) << trailingZeros; + } + + previousValue ^= xor; + return Double.longBitsToDouble(previousValue); + } + } + + /** Retrieve nested GorillaDecoder. */ + public GorillaDecoder getGorillaDecoder() { + return gorillaDecoder; + } + + /** Read all values until stream is exhausted. */ + public List<Double> getValues() throws IOException { + List<Double> list = new LinkedList<>(); + Double val; + while ((val = next()) != null) { + list.add(val); + } + return list; + } + + /** Decode next available value, return null if no more bits. */ + private Double next() throws IOException { + if (in.availableBits() <= 0) { + return null; + } Review Comment: Avoid using Double. Maybe you can use a field to indicate whether there is a next value. ########## java/tsfile/src/main/java/org/apache/tsfile/common/bitStream/BitInputStream.java: ########## @@ -0,0 +1,264 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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. + */ + +package org.apache.tsfile.common.bitStream; + +import java.io.EOFException; +import java.io.IOException; +import java.io.InputStream; + +/** A stream for reading individual bits or groups of bits from an InputStream. */ +public class BitInputStream extends BitStream { + + protected InputStream in; + protected int buffer; + protected int bufferBitCount; + protected final long totalBits; // Total valid bits + protected long bitsRead = 0; // Number of bits read so far + + protected int markedBuffer = 0; + protected int markedBufferBitCount = 0; + protected long markedBitsRead = 0; + + /** + * Constructs a BitInputStream with a given InputStream and total number of valid bits. + * + * @param in the underlying InputStream + * @param totalBits the total number of valid bits to read + */ + public BitInputStream(InputStream in, long totalBits) { + this.in = in; + this.totalBits = totalBits; + this.bufferBitCount = 0; + } + + /** + * Reads an integer value using the specified number of bits. If fewer bits are available, only + * the available bits are returned. + * + * @param numBits the number of bits to read (≤ 32) + * @return an integer whose lower bits contain the read value + * @throws EOFException if no data is available to read + * @throws IOException if an I/O error occurs + */ + public int readInt(int numBits) throws IOException { + if (availableBits() <= 0) { + throw new EOFException(); + } + + bitsRead += numBits; + int result = 0; + boolean hasReadData = false; + + while (numBits > 0) { + if (bufferBitCount == 0) { + buffer = in.read(); + if (buffer < 0) { + if (!hasReadData) { + throw new EOFException(); + } + return result; + } + bufferBitCount = BITS_PER_BYTE; + } + + if (bufferBitCount > numBits) { + result = ((buffer >> (bufferBitCount - numBits)) & MASKS[numBits]) | result; + bufferBitCount -= numBits; + numBits = 0; + } else { + result = ((buffer & MASKS[bufferBitCount]) << (numBits - bufferBitCount)) | result; + numBits -= bufferBitCount; + bufferBitCount = 0; + } + + hasReadData = true; + } + + return result; + } + + /** + * Reads a long value using the specified number of bits. + * + * @param numBits the number of bits to read (0 to 64) + * @return a long value containing the read bits + * @throws EOFException if no data is available to read + * @throws IOException if an I/O error occurs + */ + public long readLong(int numBits) throws IOException { + if (availableBits() <= 0) { + throw new EOFException(); + } + bitsRead += numBits; + if (numBits > 64 || numBits < 0) { + throw new IllegalArgumentException("numBits must be between 0 and 64"); + } + + long result = 0; + boolean hasReadData = false; + + while (numBits > 0) { + if (bufferBitCount == 0) { + buffer = in.read(); + if (buffer < 0) { + if (!hasReadData) { + throw new EOFException(); + } + return result; + } + bufferBitCount = BITS_PER_BYTE; + } + + if (bufferBitCount > numBits) { + int shift = bufferBitCount - numBits; + result = (result << numBits) | ((buffer >> shift) & MASKS[numBits]); + bufferBitCount -= numBits; + buffer &= MASKS[bufferBitCount]; + numBits = 0; + } else { + result = (result << bufferBitCount) | (buffer & MASKS[bufferBitCount]); + numBits -= bufferBitCount; + bufferBitCount = 0; + } + + hasReadData = true; + } + + return result; + } + + public static int readVarInt(BitInputStream in) throws IOException { + int result = 0; + int shift = 0; + + while (true) { + int chunk = in.readInt(7); + boolean hasNext = in.readBit(); + result |= chunk << shift; + if (!hasNext) break; + shift += 7; + if (shift >= 32) throw new IOException("VarInt too long"); + } + + return (result >>> 1) ^ -(result & 1); + } + + public static long readVarLong(BitInputStream in) throws IOException { + long result = 0; + int shift = 0; + + while (true) { + long chunk = in.readInt(7); + boolean hasNext = in.readBit(); + + result |= (chunk) << shift; + shift += 7; + + if (!hasNext) { + break; + } + + if (shift >= 64) { + throw new IOException("VarLong too long: overflow"); + } + } + + // ZigZag 解码 Review Comment: Mind this. ########## java/tsfile/src/main/java/org/apache/tsfile/encoding/decoder/CamelDecoder.java: ########## @@ -0,0 +1,273 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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. + */ + +package org.apache.tsfile.encoding.decoder; + +import org.apache.tsfile.common.bitStream.BitInputStream; +import org.apache.tsfile.common.bitStream.ByteBufferBackedInputStream; +import org.apache.tsfile.exception.encoding.TsFileDecodingException; +import org.apache.tsfile.file.metadata.enums.TSEncoding; +import org.apache.tsfile.utils.ReadWriteForEncodingUtils; + +import java.io.IOException; +import java.io.InputStream; +import java.nio.ByteBuffer; +import java.util.LinkedList; +import java.util.List; + +public class CamelDecoder extends Decoder { + // === Constants for decoding === + private static final int BITS_FOR_SIGN = 1; + private static final int BITS_FOR_TYPE = 1; + private static final int BITS_FOR_FIRST_VALUE = 64; + private static final int BITS_FOR_LEADING_ZEROS = 6; + private static final int BITS_FOR_SIGNIFICANT_BITS = 6; + private static final int BITS_FOR_DECIMAL_COUNT = 4; + private static final int DOUBLE_TOTAL_BITS = 64; + private static final int DOUBLE_MANTISSA_BITS = 52; + private static final int DECIMAL_MAX_COUNT = 15; + + // === Camel state === + private long previousValue = 0; + private boolean isFirst = true; + private long storedVal = 0; + + // === Precomputed tables === + public static final long[] powers = new long[DECIMAL_MAX_COUNT]; + public static final long[] threshold = new long[DECIMAL_MAX_COUNT]; + public static final int[] mValueBits = new int[DECIMAL_MAX_COUNT]; + + static { + for (int l = 1; l <= DECIMAL_MAX_COUNT; l++) { + int idx = l - 1; + powers[idx] = (long) Math.pow(10, l); + long divisor = 1L << l; + threshold[idx] = powers[idx] / divisor; + mValueBits[idx] = (int) Math.ceil(Math.log(threshold[idx]) / Math.log(2)); + } + } + + private BitInputStream in; + private final GorillaDecoder gorillaDecoder; + + public CamelDecoder(InputStream inputStream, long totalBits) { + super(TSEncoding.CAMEL); + // Initialize bit-level reader and nested Gorilla decoder + this.in = new BitInputStream(inputStream, totalBits); + this.gorillaDecoder = new GorillaDecoder(); + } + + public CamelDecoder() { + super(TSEncoding.CAMEL); + this.gorillaDecoder = new GorillaDecoder(); + } + + @Override + public boolean hasNext(ByteBuffer buffer) throws IOException { + if (cacheIndex < valueCache.size()) { + return true; + } + if (in != null && in.availableBits() > 0) { + return true; + } + return buffer.hasRemaining(); + } + + @Override + public void reset() { + this.in = null; + this.isFirst = true; + this.previousValue = 0L; + this.storedVal = 0L; + this.gorillaDecoder.leadingZeros = Integer.MAX_VALUE; + this.gorillaDecoder.trailingZeros = 0; + } + + // Cache for batch decoding + private List<Double> valueCache = new LinkedList<>(); + private int cacheIndex = 0; + + @Override + public double readDouble(ByteBuffer buffer) { + try { + // If the current block has been fully read, load the next block + if (cacheIndex >= valueCache.size()) { + // If no BitInputStream is available or all bits have been consumed + if (in == null || in.availableBits() == 0) { + if (!buffer.hasRemaining()) { + throw new TsFileDecodingException("No more data to decode"); + } + + ByteBuffer slice = buffer.slice(); // Keep this + ByteBufferBackedInputStream bais = new ByteBufferBackedInputStream(slice); + + // Read the number of bits in the current block + int blockBits = ReadWriteForEncodingUtils.readVarInt(bais); + this.in = new BitInputStream(bais, blockBits); + + // Reset decoder state for the new block + this.isFirst = true; + this.storedVal = 0L; + this.previousValue = 0L; + this.gorillaDecoder.leadingZeros = Integer.MAX_VALUE; + this.gorillaDecoder.trailingZeros = 0; + + // Decode the entire block into a temporary value cache + List<Double> newValues = getValues(); + if (newValues.isEmpty()) { + throw new TsFileDecodingException("Unexpected empty block"); + } + valueCache = newValues; + cacheIndex = 0; + + // Advance the buffer position by the number of bytes consumed + // int consumed = temp.length - bais.available(); + int consumed = bais.getConsumed(); + + buffer.position(buffer.position() + consumed); + } + } + + // Return the next decoded value from the cache + return valueCache.get(cacheIndex++); + } catch (IOException e) { + throw new TsFileDecodingException(e.getMessage()); + } + } + + /** Nested class to handle fallback encoding (Gorilla) for double values. */ + public class GorillaDecoder { + private int leadingZeros = Integer.MAX_VALUE; + private int trailingZeros = 0; + + /** Decode next value using Gorilla algorithm. */ + public double decode(BitInputStream in) throws IOException { + if (isFirst) { + previousValue = in.readLong(BITS_FOR_FIRST_VALUE); + isFirst = false; + return Double.longBitsToDouble(previousValue); + } + + boolean controlBit = in.readBit(); + if (!controlBit) { + return Double.longBitsToDouble(previousValue); + } + + boolean reuseBlock = !in.readBit(); + long xor; + if (reuseBlock) { + int sigBits = DOUBLE_TOTAL_BITS - leadingZeros - trailingZeros; + if (sigBits == 0) { + return Double.longBitsToDouble(previousValue); + } + xor = in.readLong(sigBits) << trailingZeros; + } else { + leadingZeros = in.readInt(BITS_FOR_LEADING_ZEROS); + int sigBits = in.readInt(BITS_FOR_SIGNIFICANT_BITS) + 1; + trailingZeros = DOUBLE_TOTAL_BITS - leadingZeros - sigBits; + xor = in.readLong(sigBits) << trailingZeros; + } + + previousValue ^= xor; + return Double.longBitsToDouble(previousValue); + } + } + + /** Retrieve nested GorillaDecoder. */ + public GorillaDecoder getGorillaDecoder() { + return gorillaDecoder; + } + + /** Read all values until stream is exhausted. */ + public List<Double> getValues() throws IOException { + List<Double> list = new LinkedList<>(); + Double val; + while ((val = next()) != null) { + list.add(val); + } + return list; + } Review Comment: LinkedList<Double> is too heavy for this task. Try your best to use double[] (a reused field, do not new it every time). ########## java/tsfile/src/main/java/org/apache/tsfile/encoding/encoder/CamelEncoder.java: ########## @@ -0,0 +1,297 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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. + */ + +package org.apache.tsfile.encoding.encoder; + +import org.apache.tsfile.common.bitStream.BitOutputStream; +import org.apache.tsfile.file.metadata.enums.TSEncoding; +import org.apache.tsfile.utils.ReadWriteForEncodingUtils; + +import java.io.ByteArrayOutputStream; +import java.io.IOException; + +public class CamelEncoder extends Encoder { + private final GorillaEncoder gorillaEncoder; + + // === Constants for encoding === + private static final int BITS_FOR_SIGN = 1; + private static final int BITS_FOR_TYPE = 1; + private static final int BITS_FOR_FIRST_VALUE = 64; + private static final int BITS_FOR_LEADING_ZEROS = 6; + private static final int BITS_FOR_SIGNIFICANT_BITS = 6; + private static final int BITS_FOR_DECIMAL_COUNT = 4; + private static final int DOUBLE_TOTAL_BITS = 64; + private static final int DOUBLE_MANTISSA_BITS = 52; + private static final int DECIMAL_MAX_COUNT = 10; + + // === Camel state === + private long storedVal = 0; + private boolean isFirst = true; + private int decimalCount = 0; + long previousValue = 0; + private boolean hasPending = false; // guard for empty or duplicate flush + + // === Precomputed tables === + public static final long[] powers = new long[DECIMAL_MAX_COUNT]; + public static final long[] threshold = new long[DECIMAL_MAX_COUNT]; + public static final int[] mValueBits = new int[DECIMAL_MAX_COUNT]; + + private final BitOutputStream out; + private final ByteArrayOutputStream baos = new ByteArrayOutputStream(); + + public CamelEncoder() { + super(TSEncoding.CAMEL); + for (int l = 1; l <= DECIMAL_MAX_COUNT; l++) { + int idx = l - 1; + powers[idx] = (long) Math.pow(10, l); + long divisor = 1L << l; + threshold[idx] = powers[idx] / divisor; + mValueBits[idx] = (int) Math.ceil(Math.log(threshold[idx]) / Math.log(2)); + } Review Comment: Use static initialization. -- This is an automated message from the Apache Git Service. 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