cn.wjybxx.dson.internal.CodedUtils Maven / Gradle / Ivy
/*
* Copyright 2023-2024 wjybxx([email protected])
*
* 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.
*/
package cn.wjybxx.dson.internal;
import cn.wjybxx.base.mutable.MutableInt;
import cn.wjybxx.dson.io.DsonIOException;
/**
* 以下参考自protobuf，以避免引入PB
*
* @author wjybxx
* date 2023/3/31
*/
@SuppressWarnings("unused")
public final class CodedUtils {
private CodedUtils() {
}
private static final int IntCodedMask1 = (-1) << 7; // 低7位0
private static final int IntCodedMask2 = (-1) << 14; // 低14位0
private static final int IntCodedMask3 = (-1) << 21;
private static final int IntCodedMask4 = (-1) << 28;
private static final long LongCodedMask1 = (-1L) << 7;
private static final long LongCodedMask2 = (-1L) << 14;
private static final long LongCodedMask3 = (-1L) << 21;
private static final long LongCodedMask4 = (-1L) << 28;
private static final long LongCodedMask5 = (-1L) << 35;
private static final long LongCodedMask6 = (-1L) << 42;
private static final long LongCodedMask7 = (-1L) << 49;
private static final long LongCodedMask8 = (-1L) << 56;
private static final long LongCodedMask9 = (-1L) << 63;
/** 计算原始的32位变长整形的编码长度 */
public static int computeRawVarInt32Size(int value) {
if ((value & IntCodedMask1) == 0) return 1; // 所有高位为0
if ((value & IntCodedMask2) == 0) return 2;
if ((value & IntCodedMask3) == 0) return 3;
if ((value & IntCodedMask4) == 0) return 4;
return 5;
}
/** 计算原始的64位变长整形的编码长度 */
public static int computeRawVarInt64Size(long value) {
if ((value & LongCodedMask1) == 0) return 1; // 所有高位为0
if ((value & LongCodedMask2) == 0) return 2;
if ((value & LongCodedMask3) == 0) return 3;
if ((value & LongCodedMask4) == 0) return 4;
if ((value & LongCodedMask5) == 0) return 5;
if ((value & LongCodedMask6) == 0) return 6;
if ((value & LongCodedMask7) == 0) return 7;
if ((value & LongCodedMask8) == 0) return 8;
if ((value & LongCodedMask9) == 0) return 9;
return 10;
}
public static int encodeZigZag32(int n) {
return (n << 1) ^ (n >> 31);
}
public static int decodeZigZag32(final int n) {
return (n >>> 1) ^ -(n & 1);
}
public static long encodeZigZag64(long n) {
return (n << 1) ^ (n >> 63);
}
public static long decodeZigZag64(final long n) {
return (n >>> 1) ^ -(n & 1);
}
//region protobuf decode
public static int readInt32(byte[] buffer, int pos, MutableInt newPos) {
long rawBits = readRawVarint64(buffer, pos, newPos);
return (int) rawBits;
}
public static long readInt64(byte[] buffer, int pos, MutableInt newPos) {
return readRawVarint64(buffer, pos, newPos);
}
public static int readUint32(byte[] buffer, int pos, MutableInt newPos) {
return (int) readRawVarint64(buffer, pos, newPos);
}
public static long readUint64(byte[] buffer, int pos, MutableInt newPos) {
return readRawVarint64(buffer, pos, newPos);
}
public static int readSint32(byte[] buffer, int pos, MutableInt newPos) {
long rawBits = readRawVarint64(buffer, pos, newPos);
return decodeZigZag32((int) rawBits);
}
public static long readSint64(byte[] buffer, int pos, MutableInt newPos) {
long rawBits = readRawVarint64(buffer, pos, newPos);
return decodeZigZag64(rawBits);
}
public static int readFixed32(byte[] buffer, int pos, MutableInt newPos) {
return readRawFixed32(buffer, pos, newPos);
}
public static long readFixed64(byte[] buffer, int pos, MutableInt newPos) {
return readRawFixed64(buffer, pos, newPos);
}
public static float readFloat(byte[] buffer, int pos, MutableInt newPos) {
int rawBits = readRawFixed32(buffer, pos, newPos);
return Float.intBitsToFloat(rawBits);
}
public static double readDouble(byte[] buffer, int pos, MutableInt newPos) {
long rawBits = readRawFixed64(buffer, pos, newPos);
return Double.longBitsToDouble(rawBits);
}
/** varint编码不区分int和long，而是固定读取到高位字节为0，因此无需两个方法 */
private static long readRawVarint64(byte[] buffer, int pos, MutableInt newPos) {
// 单字节优化
byte b = buffer[pos++];
long r = (b & 127L);
if ((b & 128) == 0) {
newPos.setValue(pos);
return r;
}
int shift = 7;
do {
b = buffer[pos++];
r |= (b & 127L) << shift; // 取后7位左移
if ((b & 128) == 0) { // 高位0
newPos.setValue(pos);
return r;
}
shift += 7;
} while (shift < 64);
// 读取超过10个字节
throw new DsonIOException("DsonInput encountered a malformed varint.");
}
private static int readRawFixed32(byte[] buffer, int pos, MutableInt newPos) {
int r = (((buffer[pos] & 0xff))
| ((buffer[pos + 1] & 0xff) << 8)
| ((buffer[pos + 2] & 0xff) << 16)
| ((buffer[pos + 3] & 0xff) << 24));
newPos.setValue(pos + 4);
return r;
}
private static long readRawFixed64(byte[] buffer, int pos, MutableInt newPos) {
long r = (((buffer[pos] & 0xffL))
| ((buffer[pos + 1] & 0xffL) << 8)
| ((buffer[pos + 2] & 0xffL) << 16)
| ((buffer[pos + 3] & 0xffL) << 24)
| ((buffer[pos + 4] & 0xffL) << 32)
| ((buffer[pos + 5] & 0xffL) << 40)
| ((buffer[pos + 6] & 0xffL) << 48)
| ((buffer[pos + 7] & 0xffL) << 56));
newPos.setValue(pos + 8);
return r;
}
//endregion
//region protobuf encode
/** @return newPos */
public static int writeInt32(byte[] buffer, int pos, int value) {
if (value >= 0) {
return writeRawVarint32(buffer, pos, value);
} else {
return writeRawVarint64(buffer, pos, value);
}
}
public static int writeInt64(byte[] buffer, int pos, long value) {
return writeRawVarint64(buffer, pos, value);
}
public static int writeUint32(byte[] buffer, int pos, int value) {
return writeRawVarint32(buffer, pos, value);
}
public static int writeUint64(byte[] buffer, int pos, long value) {
return writeRawVarint64(buffer, pos, value);
}
public static int writeSint32(byte[] buffer, int pos, int value) {
return writeRawVarint32(buffer, pos, encodeZigZag32(value));
}
public static int writeSint64(byte[] buffer, int pos, long value) {
return writeRawVarint64(buffer, pos, encodeZigZag64(value));
}
public static int writeFixed32(byte[] buffer, int pos, int value) {
return writeRawFixed32(buffer, pos, value);
}
public static int writeFixed64(byte[] buffer, int pos, long value) {
return writeRawFixed64(buffer, pos, value);
}
public static int writeFloat(byte[] buffer, int pos, float value) {
return writeRawFixed32(buffer, pos, Float.floatToRawIntBits(value));
}
public static int writeDouble(byte[] buffer, int pos, double value) {
return writeRawFixed64(buffer, pos, Double.doubleToRawLongBits(value));
}
/**
* 写入一个变长的64位整数，所有的负数都将固定10字节
*
* @param buffer buffer
* @param pos 开始写入的位置
* @param value 要写入的值
* @return 写入后的新坐标
*/
private static int writeRawVarint64(byte[] buffer, int pos, long value) {
if (value >= 0 && value < 128L) { // 小数值较多的情况下有意义
buffer[pos] = (byte) value;
return pos + 1;
}
while (true) {
if ((value & LongCodedMask1) != 0) {
buffer[pos++] = (byte) ((value & 127L) | 128L); // 截取后7位，高位补1
value >>>= 7; // java必须逻辑右移
} else {
buffer[pos++] = (byte) value;
return pos;
}
}
}
/**
* 写入一个变长的32位整数，负数将固定为5字节
* （注意：普通int慎重调用，这里将int看做无符号整数编码）
*
* @param buffer buffer
* @param pos 开始写入的位置
* @param value 要写入的值
* @return 写入后的新坐标
*/
private static int writeRawVarint32(byte[] buffer, int pos, int value) {
if (value >= 0 && value < 128) { // 小数值较多的情况下有意义
buffer[pos] = (byte) value;
return pos + 1;
}
while (true) {
if ((value & IntCodedMask1) != 0) {
buffer[pos++] = (byte) ((value & 127) | 128); // 截取后7位，高位补1
value >>>= 7; // java必须逻辑右移
} else {
buffer[pos++] = (byte) value;
return pos;
}
}
}
private static int writeRawFixed32(byte[] buffer, int pos, int value) {
buffer[pos] = (byte) value;
buffer[pos + 1] = (byte) (value >> 8);
buffer[pos + 2] = (byte) (value >> 16);
buffer[pos + 3] = (byte) (value >> 24);
return pos + 4;
}
private static int writeRawFixed64(byte[] buffer, int pos, long value) {
buffer[pos] = (byte) value;
buffer[pos + 1] = (byte) (value >> 8);
buffer[pos + 2] = (byte) (value >> 16);
buffer[pos + 3] = (byte) (value >> 24);
buffer[pos + 4] = (byte) (value >> 32);
buffer[pos + 5] = (byte) (value >> 40);
buffer[pos + 6] = (byte) (value >> 48);
buffer[pos + 7] = (byte) (value >> 56);
return pos + 8;
}
//endregion
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