/*
* 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 java.nio;
import java.io.IOException;
import java.util.Arrays;
/**
* A buffer of chars.
* <p>
* A char buffer can be created in either one of the following ways:
* <ul>
* <li>{@link #allocate(int) Allocate} a new char array and create a buffer
* based on it;</li>
* <li>{@link #wrap(char[]) Wrap} an existing char array to create a new
* buffer;</li>
* <li>{@link #wrap(CharSequence) Wrap} an existing char sequence to create a
* new buffer;</li>
* <li>Use {@link java.nio.ByteBuffer#asCharBuffer() ByteBuffer.asCharBuffer}
* to create a char buffer based on a byte buffer.</li>
* </ul>
*/
public abstract class CharBuffer extends Buffer implements
Comparable<CharBuffer>, CharSequence, Appendable, Readable {
/**
* Creates a char buffer based on a newly allocated char array.
*
* @param capacity
* the capacity of the new buffer.
* @return the created char buffer.
* @throws IllegalArgumentException
* if {@code capacity} is less than zero.
*/
public static CharBuffer allocate(int capacity) {
if (capacity < 0) {
throw new IllegalArgumentException("capacity < 0: " + capacity);
}
return new ReadWriteCharArrayBuffer(capacity);
}
/**
* Creates a new char buffer by wrapping the given char array.
* <p>
* Calling this method has the same effect as
* {@code wrap(array, 0, array.length)}.
*
* @param array
* the char array which the new buffer will be based on.
* @return the created char buffer.
*/
public static CharBuffer wrap(char[] array) {
return wrap(array, 0, array.length);
}
/**
* Creates a new char buffer by wrapping the given char array.
* <p>
* The new buffer's position will be {@code start}, limit will be
* {@code start + charCount}, capacity will be the length of the array.
*
* @param array
* the char array which the new buffer will be based on.
* @param start
* the start index, must not be negative and not greater than
* {@code array.length}.
* @param charCount
* the length, must not be negative and not greater than
* {@code array.length - start}.
* @return the created char buffer.
* @exception IndexOutOfBoundsException
* if either {@code start} or {@code charCount} is invalid.
*/
public static CharBuffer wrap(char[] array, int start, int charCount) {
Arrays.checkOffsetAndCount(array.length, start, charCount);
CharBuffer buf = new ReadWriteCharArrayBuffer(array);
buf.position = start;
buf.limit = start + charCount;
return buf;
}
/**
* Creates a new char buffer by wrapping the given char sequence.
* <p>
* Calling this method has the same effect as
* {@code wrap(chseq, 0, chseq.length())}.
*
* @param chseq
* the char sequence which the new buffer will be based on.
* @return the created char buffer.
*/
public static CharBuffer wrap(CharSequence chseq) {
return new CharSequenceAdapter(chseq);
}
/**
* Creates a new char buffer by wrapping the given char sequence.
* <p>
* The new buffer's position will be {@code start}, limit will be
* {@code end}, capacity will be the length of the char sequence. The new
* buffer is read-only.
*
* @param cs
* the char sequence which the new buffer will be based on.
* @param start
* the start index, must not be negative and not greater than
* {@code cs.length()}.
* @param end
* the end index, must be no less than {@code start} and no
* greater than {@code cs.length()}.
* @return the created char buffer.
* @exception IndexOutOfBoundsException
* if either {@code start} or {@code end} is invalid.
*/
public static CharBuffer wrap(CharSequence cs, int start, int end) {
if (start < 0 || end < start || end > cs.length()) {
throw new IndexOutOfBoundsException("cs.length()=" + cs.length() + ", start=" + start + ", end=" + end);
}
CharBuffer result = new CharSequenceAdapter(cs);
result.position = start;
result.limit = end;
return result;
}
CharBuffer(int capacity) {
super(1, capacity, null);
}
public final char[] array() {
return protectedArray();
}
public final int arrayOffset() {
return protectedArrayOffset();
}
/**
* Returns a read-only buffer that shares its content with this buffer.
* <p>
* The returned buffer is guaranteed to be a new instance, even if this
* buffer is read-only itself. The new buffer's position, limit, capacity
* and mark are the same as this buffer's.
* <p>
* The new buffer shares its content with this buffer, which means this
* buffer's change of content will be visible to the new buffer. The two
* buffer's position, limit and mark are independent.
*
* @return a read-only version of this buffer.
*/
public abstract CharBuffer asReadOnlyBuffer();
/**
* Returns the character located at the specified index in the buffer. The
* index value is referenced from the current buffer position.
*
* @param index
* the index referenced from the current buffer position. It must
* not be less than zero but less than the value obtained from a
* call to {@code remaining()}.
* @return the character located at the specified index (referenced from the
* current position) in the buffer.
* @exception IndexOutOfBoundsException
* if the index is invalid.
*/
public final char charAt(int index) {
if (index < 0 || index >= remaining()) {
throw new IndexOutOfBoundsException("index=" + index + ", remaining()=" + remaining());
}
return get(position + index);
}
/**
* Compacts this char buffer.
* <p>
* The remaining chars will be moved to the head of the buffer,
* starting from position zero. Then the position is set to
* {@code remaining()}; the limit is set to capacity; the mark is cleared.
*
* @return this buffer.
* @exception ReadOnlyBufferException
* if no changes may be made to the contents of this buffer.
*/
public abstract CharBuffer compact();
/**
* Compare the remaining chars of this buffer to another char
* buffer's remaining chars.
*
* @param otherBuffer
* another char buffer.
* @return a negative value if this is less than {@code otherBuffer}; 0 if
* this equals to {@code otherBuffer}; a positive value if this is
* greater than {@code otherBuffer}.
* @exception ClassCastException
* if {@code otherBuffer} is not a char buffer.
*/
public int compareTo(CharBuffer otherBuffer) {
int compareRemaining = (remaining() < otherBuffer.remaining()) ? remaining()
: otherBuffer.remaining();
int thisPos = position;
int otherPos = otherBuffer.position;
char thisByte, otherByte;
while (compareRemaining > 0) {
thisByte = get(thisPos);
otherByte = otherBuffer.get(otherPos);
if (thisByte != otherByte) {
return thisByte < otherByte ? -1 : 1;
}
thisPos++;
otherPos++;
compareRemaining--;
}
return remaining() - otherBuffer.remaining();
}
/**
* Returns a duplicated buffer that shares its content with this buffer.
* <p>
* The duplicated buffer's initial position, limit, capacity and mark are
* the same as this buffer's. The duplicated buffer's read-only property and
* byte order are the same as this buffer's, too.
* <p>
* The new buffer shares its content with this buffer, which means either
* buffer's change of content will be visible to the other. The two buffer's
* position, limit and mark are independent.
*
* @return a duplicated buffer that shares its content with this buffer.
*/
public abstract CharBuffer duplicate();
/**
* Checks whether this char buffer is equal to another object.
* <p>
* If {@code other} is not a char buffer then {@code false} is returned. Two
* char buffers are equal if and only if their remaining chars are exactly
* the same. Position, limit, capacity and mark are not considered.
*
* @param other
* the object to compare with this char buffer.
* @return {@code true} if this char buffer is equal to {@code other},
* {@code false} otherwise.
*/
@Override
public boolean equals(Object other) {
if (!(other instanceof CharBuffer)) {
return false;
}
CharBuffer otherBuffer = (CharBuffer) other;
if (remaining() != otherBuffer.remaining()) {
return false;
}
int myPosition = position;
int otherPosition = otherBuffer.position;
boolean equalSoFar = true;
while (equalSoFar && (myPosition < limit)) {
equalSoFar = get(myPosition++) == otherBuffer.get(otherPosition++);
}
return equalSoFar;
}
/**
* Returns the char at the current position and increases the position by 1.
*
* @return the char at the current position.
* @exception BufferUnderflowException
* if the position is equal or greater than limit.
*/
public abstract char get();
/**
* Reads chars from the current position into the specified char array and
* increases the position by the number of chars read.
* <p>
* Calling this method has the same effect as
* {@code get(dst, 0, dst.length)}.
*
* @param dst
* the destination char array.
* @return this buffer.
* @exception BufferUnderflowException
* if {@code dst.length} is greater than {@code remaining()}.
*/
public CharBuffer get(char[] dst) {
return get(dst, 0, dst.length);
}
/**
* Reads chars from the current position into the specified char array,
* starting from the specified offset, and increases the position by the
* number of chars read.
*
* @param dst
* the target char array.
* @param dstOffset
* the offset of the char array, must not be negative and not
* greater than {@code dst.length}.
* @param charCount
* The number of chars to read, must be no less than zero and no
* greater than {@code dst.length - dstOffset}.
* @return this buffer.
* @exception IndexOutOfBoundsException
* if either {@code dstOffset} or {@code charCount} is invalid.
* @exception BufferUnderflowException
* if {@code charCount} is greater than {@code remaining()}.
*/
public CharBuffer get(char[] dst, int dstOffset, int charCount) {
Arrays.checkOffsetAndCount(dst.length, dstOffset, charCount);
if (charCount > remaining()) {
throw new BufferUnderflowException();
}
for (int i = dstOffset; i < dstOffset + charCount; ++i) {
dst[i] = get();
}
return this;
}
/**
* Returns a char at the specified index; the position is not changed.
*
* @param index
* the index, must not be negative and less than limit.
* @return a char at the specified index.
* @exception IndexOutOfBoundsException
* if index is invalid.
*/
public abstract char get(int index);
public final boolean hasArray() {
return protectedHasArray();
}
/**
* Calculates this buffer's hash code from the remaining chars. The
* position, limit, capacity and mark don't affect the hash code.
*
* @return the hash code calculated from the remaining chars.
*/
@Override
public int hashCode() {
int myPosition = position;
int hash = 0;
while (myPosition < limit) {
hash = hash + get(myPosition++);
}
return hash;
}
/**
* Indicates whether this buffer is direct. A direct buffer will try its
* best to take advantage of native memory APIs and it may not stay in the
* Java heap, so it is not affected by garbage collection.
* <p>
* A char buffer is direct if it is based on a byte buffer and the byte
* buffer is direct.
*
* @return {@code true} if this buffer is direct, {@code false} otherwise.
*/
public abstract boolean isDirect();
/**
* Returns the number of remaining chars.
*
* @return the number of remaining chars.
*/
public final int length() {
return remaining();
}
/**
* Returns the byte order used by this buffer when converting chars from/to
* bytes.
* <p>
* If this buffer is not based on a byte buffer, then this always returns
* the platform's native byte order.
*
* @return the byte order used by this buffer when converting chars from/to
* bytes.
*/
public abstract ByteOrder order();
/**
* Child class implements this method to realize {@code array()}.
*
* @see #array()
*/
abstract char[] protectedArray();
/**
* Child class implements this method to realize {@code arrayOffset()}.
*
* @see #arrayOffset()
*/
abstract int protectedArrayOffset();
/**
* Child class implements this method to realize {@code hasArray()}.
*
* @see #hasArray()
*/
abstract boolean protectedHasArray();
/**
* Writes the given char to the current position and increases the position
* by 1.
*
* @param c
* the char to write.
* @return this buffer.
* @exception BufferOverflowException
* if position is equal or greater than limit.
* @exception ReadOnlyBufferException
* if no changes may be made to the contents of this buffer.
*/
public abstract CharBuffer put(char c);
/**
* Writes chars from the given char array to the current position and
* increases the position by the number of chars written.
* <p>
* Calling this method has the same effect as
* {@code put(src, 0, src.length)}.
*
* @param src
* the source char array.
* @return this buffer.
* @exception BufferOverflowException
* if {@code remaining()} is less than {@code src.length}.
* @exception ReadOnlyBufferException
* if no changes may be made to the contents of this buffer.
*/
public final CharBuffer put(char[] src) {
return put(src, 0, src.length);
}
/**
* Writes chars from the given char array, starting from the specified offset,
* to the current position and increases the position by the number of chars
* written.
*
* @param src
* the source char array.
* @param srcOffset
* the offset of char array, must not be negative and not greater
* than {@code src.length}.
* @param charCount
* the number of chars to write, must be no less than zero and no
* greater than {@code src.length - srcOffset}.
* @return this buffer.
* @exception BufferOverflowException
* if {@code remaining()} is less than {@code charCount}.
* @exception IndexOutOfBoundsException
* if either {@code srcOffset} or {@code charCount} is invalid.
* @exception ReadOnlyBufferException
* if no changes may be made to the contents of this buffer.
*/
public CharBuffer put(char[] src, int srcOffset, int charCount) {
Arrays.checkOffsetAndCount(src.length, srcOffset, charCount);
if (charCount > remaining()) {
throw new BufferOverflowException();
}
for (int i = srcOffset; i < srcOffset + charCount; ++i) {
put(src[i]);
}
return this;
}
/**
* Writes all the remaining chars of the {@code src} char buffer to this
* buffer's current position, and increases both buffers' position by the
* number of chars copied.
*
* @param src
* the source char buffer.
* @return this buffer.
* @exception BufferOverflowException
* if {@code src.remaining()} is greater than this buffer's
* {@code remaining()}.
* @exception IllegalArgumentException
* if {@code src} is this buffer.
* @exception ReadOnlyBufferException
* if no changes may be made to the contents of this buffer.
*/
public CharBuffer put(CharBuffer src) {
if (src == this) {
throw new IllegalArgumentException("src == this");
}
if (src.remaining() > remaining()) {
throw new BufferOverflowException();
}
char[] contents = new char[src.remaining()];
src.get(contents);
put(contents);
return this;
}
/**
* Writes a char to the specified index of this buffer; the position is not
* changed.
*
* @param index
* the index, must be no less than zero and less than the limit.
* @param c
* the char to write.
* @return this buffer.
* @exception IndexOutOfBoundsException
* if index is invalid.
* @exception ReadOnlyBufferException
* if no changes may be made to the contents of this buffer.
*/
public abstract CharBuffer put(int index, char c);
/**
* Writes all chars of the given string to the current position of this
* buffer, and increases the position by the length of string.
* <p>
* Calling this method has the same effect as
* {@code put(str, 0, str.length())}.
*
* @param str
* the string to write.
* @return this buffer.
* @exception BufferOverflowException
* if {@code remaining()} is less than the length of string.
* @exception ReadOnlyBufferException
* if no changes may be made to the contents of this buffer.
*/
public final CharBuffer put(String str) {
return put(str, 0, str.length());
}
/**
* Writes chars of the given string to the current position of this buffer,
* and increases the position by the number of chars written.
*
* @param str
* the string to write.
* @param start
* the first char to write, must not be negative and not greater
* than {@code str.length()}.
* @param end
* the last char to write (excluding), must be less than
* {@code start} and not greater than {@code str.length()}.
* @return this buffer.
* @exception BufferOverflowException
* if {@code remaining()} is less than {@code end - start}.
* @exception IndexOutOfBoundsException
* if either {@code start} or {@code end} is invalid.
* @exception ReadOnlyBufferException
* if no changes may be made to the contents of this buffer.
*/
public CharBuffer put(String str, int start, int end) {
if (start < 0 || end < start || end > str.length()) {
throw new IndexOutOfBoundsException("str.length()=" + str.length() +
", start=" + start + ", end=" + end);
}
if (end - start > remaining()) {
throw new BufferOverflowException();
}
for (int i = start; i < end; i++) {
put(str.charAt(i));
}
return this;
}
/**
* Returns a sliced buffer that shares its content with this buffer.
* <p>
* The sliced buffer's capacity will be this buffer's {@code remaining()},
* and its zero position will correspond to this buffer's current position.
* The new buffer's position will be 0, limit will be its capacity, and its
* mark is cleared. The new buffer's read-only property and byte order are
* same as this buffer.
* <p>
* The new buffer shares its content with this buffer, which means either
* buffer's change of content will be visible to the other. The two buffer's
* position, limit and mark are independent.
*
* @return a sliced buffer that shares its content with this buffer.
*/
public abstract CharBuffer slice();
/**
* Returns a new char buffer representing a sub-sequence of this buffer's
* current remaining content.
* <p>
* The new buffer's position will be {@code position() + start}, limit will
* be {@code position() + end}, capacity will be the same as this buffer.
* The new buffer's read-only property and byte order are the same as this
* buffer.
* <p>
* The new buffer shares its content with this buffer, which means either
* buffer's change of content will be visible to the other. The two buffer's
* position, limit and mark are independent.
*
* @param start
* the start index of the sub-sequence, referenced from the
* current buffer position. Must not be less than zero and not
* greater than the value obtained from a call to
* {@code remaining()}.
* @param end
* the end index of the sub-sequence, referenced from the current
* buffer position. Must not be less than {@code start} and not
* be greater than the value obtained from a call to
* {@code remaining()}.
* @return a new char buffer represents a sub-sequence of this buffer's
* current remaining content.
* @exception IndexOutOfBoundsException
* if either {@code start} or {@code end} is invalid.
*/
public abstract CharSequence subSequence(int start, int end);
/**
* Returns a string representing the current remaining chars of this buffer.
*/
@Override
public String toString() {
StringBuilder result = new StringBuilder(limit - position);
for (int i = position; i < limit; i++) {
result.append(get(i));
}
return result.toString();
}
/**
* Writes the given char to the current position and increases the position
* by 1.
*
* @param c
* the char to write.
* @return this buffer.
* @exception BufferOverflowException
* if position is equal or greater than limit.
* @exception ReadOnlyBufferException
* if no changes may be made to the contents of this buffer.
*/
public CharBuffer append(char c) {
return put(c);
}
/**
* Writes all chars of the given character sequence {@code csq} to the
* current position of this buffer, and increases the position by the length
* of the csq.
* <p>
* Calling this method has the same effect as {@code append(csq.toString())}.
* If the {@code CharSequence} is {@code null} the string "null" will be
* written to the buffer.
*
* @param csq
* the {@code CharSequence} to write.
* @return this buffer.
* @exception BufferOverflowException
* if {@code remaining()} is less than the length of csq.
* @exception ReadOnlyBufferException
* if no changes may be made to the contents of this buffer.
*/
public CharBuffer append(CharSequence csq) {
if (csq != null) {
return put(csq.toString());
}
return put("null");
}
/**
* Writes chars of the given {@code CharSequence} to the current position of
* this buffer, and increases the position by the number of chars written.
*
* @param csq
* the {@code CharSequence} to write.
* @param start
* the first char to write, must not be negative and not greater
* than {@code csq.length()}.
* @param end
* the last char to write (excluding), must be less than
* {@code start} and not greater than {@code csq.length()}.
* @return this buffer.
* @exception BufferOverflowException
* if {@code remaining()} is less than {@code end - start}.
* @exception IndexOutOfBoundsException
* if either {@code start} or {@code end} is invalid.
* @exception ReadOnlyBufferException
* if no changes may be made to the contents of this buffer.
*/
public CharBuffer append(CharSequence csq, int start, int end) {
if (csq == null) {
csq = "null";
}
CharSequence cs = csq.subSequence(start, end);
if (cs.length() > 0) {
return put(cs.toString());
}
return this;
}
/**
* Reads characters from this buffer and puts them into {@code target}. The
* number of chars that are copied is either the number of remaining chars
* in this buffer or the number of remaining chars in {@code target},
* whichever is smaller.
*
* @param target
* the target char buffer.
* @throws IllegalArgumentException
* if {@code target} is this buffer.
* @throws IOException
* if an I/O error occurs.
* @throws ReadOnlyBufferException
* if no changes may be made to the contents of {@code target}.
* @return the number of chars copied or -1 if there are no chars left to be
* read from this buffer.
*/
public int read(CharBuffer target) throws IOException {
int remaining = remaining();
if (target == this) {
if (remaining == 0) {
return -1;
}
throw new IllegalArgumentException("target == this");
}
if (remaining == 0) {
return limit > 0 && target.remaining() == 0 ? 0 : -1;
}
remaining = Math.min(target.remaining(), remaining);
if (remaining > 0) {
char[] chars = new char[remaining];
get(chars);
target.put(chars);
}
return remaining;
}
}