netty5/buffer/src/main/java/io/net5/buffer/api/ByteCursor.java

73 lines
2.7 KiB
Java

/*
* Copyright 2021 The Netty Project
*
* The Netty Project 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:
*
* https://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 io.net5.buffer.api;
import io.net5.util.ByteProcessor;
/**
* The ByteCursor scans through a sequence of bytes.
* This is similar to {@link ByteProcessor}, but for external iteration rather than internal iteration.
* The external iteration allows the callers to control the pace of the iteration.
*/
public interface ByteCursor {
/**
* Check if the iterator has at least one byte left, and if so, read that byte and move the cursor forward.
* The byte will then be available through the {@link #getByte()}.
*
* @return {@code true} if the cursor read a byte and moved forward, otherwise {@code false}.
*/
boolean readByte();
/**
* Return the last byte that was read by {@link #readByte()}.
* If {@link #readByte()} has not been called on this cursor before, then {@code -1} is returned.
*
* @return The next byte that was read by the most recent successful call to {@link #readByte()}.
*/
byte getByte();
/**
* The current position of this iterator into the underlying sequence of bytes.
* For instance, if we are iterating a buffer, this would be the iterators current offset into the buffer.
*
* @return The current iterator offset into the underlying sequence of bytes.
*/
int currentOffset();
/**
* Get the current number of bytes left in the iterator.
*
* @return The number of bytes left in the iterator.
*/
int bytesLeft();
/**
* Process the remaining bytes in this iterator with the given {@link ByteProcessor}.
* This method consumes the iterator.
*
* @param processor The processor to use for processing the bytes in the iterator.
* @return The number of bytes processed, if the {@link ByteProcessor#process(byte) process} method returned
* {@code false}, or {@code -1} if the whole iterator was processed.
*/
default int process(ByteProcessor processor) {
boolean requestMore = true;
int count = 0;
while (readByte() && (requestMore = processor.process(getByte()))) {
count++;
}
return requestMore? -1 : count;
}
}