net.openhft.chronicle.bytes.util.BinaryLengthLength Maven / Gradle / Ivy
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/*
* Copyright (c) 2016-2022 chronicle.software
*
* https://chronicle.software
*
* 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 net.openhft.chronicle.bytes.util;
import net.openhft.chronicle.bytes.BinaryWireCode;
import net.openhft.chronicle.bytes.Bytes;
import net.openhft.chronicle.bytes.BytesOut;
import net.openhft.chronicle.core.UnsafeMemory;
import net.openhft.chronicle.core.annotation.NonNegative;
import org.jetbrains.annotations.NotNull;
/**
* Enum representing different byte lengths for binary values.
* It provides methods to get the code associated with each byte length,
* to initialize a {@link BytesOut} object with the length code, and
* to write the length of the data into the {@link Bytes} object.
*/
public enum BinaryLengthLength {
/**
* Represents an 8-bit length encoding for binary data.
*/
LENGTH_8BIT {
/**
* Returns the code representing 8-bit length.
*
* @return The code for the 8-bit length.
*/
@Override
public int code() {
return BinaryWireCode.BYTES_LENGTH8;
}
/**
* Initializes a {@link BytesOut} object with the length code.
*
* @param bytes The {@link BytesOut} object to initialize.
* @return The position within the {@link BytesOut} where the length will be written.
*/
@Override
public long initialise(@NotNull final BytesOut bytes) {
bytes.writeUnsignedByte(code());
long pos = bytes.writePosition();
bytes.writeByte((byte) 0);
return pos;
}
/**
* Writes the length of the data into the {@link Bytes} object.
*
* @param bytes The {@link Bytes} object to write to.
* @param positionReturnedFromInitialise The position within the {@link Bytes} to write the length.
* @param end The end position of the data within the {@link Bytes}.
*/
@Override
public void writeLength(@NotNull Bytes bytes, @NonNegative long positionReturnedFromInitialise, @NonNegative long end) {
long length = (end - positionReturnedFromInitialise - 1) & MASK;
if (length >= 1 << 8)
throw invalidLength(length);
bytes.writeByte(positionReturnedFromInitialise, (byte) length);
UnsafeMemory.MEMORY.storeFence(); // Ensures that the write is flushed to memory
}
},
/**
* Represents a 16-bit length encoding for binary data.
*/
LENGTH_16BIT {
/**
* Returns the code representing 16-bit length.
*
* @return The code for the 16-bit length.
*/
@Override
public int code() {
return BinaryWireCode.BYTES_LENGTH16;
}
/**
* Initializes a {@link BytesOut} object with the length code.
*
* @param bytes The {@link BytesOut} object to initialize.
* @return The position within the {@link BytesOut} where the length will be written.
*/
@Override
public long initialise(@NotNull final BytesOut bytes) {
bytes.writeUnsignedByte(code());
final long pos = bytes.writePosition();
bytes.writeShort((short) 0);
return pos;
}
/**
* Writes the length of the data into the {@link Bytes} object.
*
* @param bytes The {@link Bytes} object to write to.
* @param positionReturnedFromInitialise The position within the {@link Bytes} to write the length.
* @param end The end position of the data within the {@link Bytes}.
*/
@Override
public void writeLength(@NotNull Bytes bytes, @NonNegative long positionReturnedFromInitialise, @NonNegative long end) {
final long length = (end - positionReturnedFromInitialise - 2) & MASK;
if (length >= 1 << 16)
throw invalidLength(length);
bytes.writeShort(positionReturnedFromInitialise, (short) length);
UnsafeMemory.MEMORY.storeFence(); // Ensures that the write is flushed to memory
}
},
/**
* Represents a 32-bit length encoding for binary data.
*/
LENGTH_32BIT {
/**
* Returns the code representing 32-bit length.
*
* @return The code for the 32-bit length.
*/
@Override
public int code() {
return BinaryWireCode.BYTES_LENGTH32;
}
/**
* Initializes a {@link BytesOut} object with the length code.
*
* @param bytes The {@link BytesOut} object to initialize.
* @return The position within the {@link BytesOut} where the length will be written.
*/
@Override
public long initialise(@NotNull BytesOut bytes) {
bytes.writeUnsignedByte(code());
final long pos = bytes.writePosition();
bytes.writeInt(0);
return pos;
}
/**
* Writes the length of the data into the {@link Bytes} object.
*
* @param bytes The {@link Bytes} object to write to.
* @param positionReturnedFromInitialise The position within the {@link Bytes} to write the length.
* @param end The end position of the data within the {@link Bytes}.
*/
@Override
public void writeLength(@NotNull Bytes bytes, @NonNegative long positionReturnedFromInitialise, @NonNegative long end) {
final long length = (end - positionReturnedFromInitialise - 4) & MASK;
if (length >= 1L << 31)
throw invalidLength(length);
bytes.writeOrderedInt(positionReturnedFromInitialise, (int) length);
}
};
static final long MASK = 0xFFFFFFFFL;
/**
* Constructs an IllegalStateException for an invalid length.
*
* @param length the invalid length
* @return the IllegalStateException instance with a message regarding the invalid length
*/
IllegalStateException invalidLength(@NonNegative final long length) {
return new IllegalStateException("length: " + length);
}
/**
* Returns the code representing the length encoding.
*
* @return the length encoding code
*/
public abstract int code();
/**
* Initialises the binary data with the appropriate length encoding.
*
* @param bytes the output bytes to write to
* @return the position where the length encoding starts
*/
public abstract long initialise(@NotNull BytesOut bytes);
/**
* Writes the length of the data into the {@link Bytes} object.
*
* @param bytes The {@link Bytes} object to write to.
* @param positionReturnedFromInitialise The position within the {@link Bytes} to write the length.
* @param end The end position of the data within the {@link Bytes}.
*/
public abstract void writeLength(@NotNull Bytes bytes, @NonNegative long positionReturnedFromInitialise, @NonNegative long end);
}
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