761417898 commented on code in PR #560: URL: https://github.com/apache/tsfile/pull/560#discussion_r2250741227
########## 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: fixed -- This is an automated message from the Apache Git Service. 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