ByteString.java
/*
* 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.calcite.avatica.util;
import com.fasterxml.jackson.annotation.JsonValue;
import java.io.IOException;
import java.io.Serializable;
import java.util.Arrays;
/**
* Collection of bytes.
*
* <p>ByteString is to bytes what {@link String} is to chars: It is immutable,
* implements equality ({@link #hashCode} and {@link #equals}),
* comparison ({@link #compareTo}) and
* {@link Serializable serialization} correctly.</p>
*/
public class ByteString implements Comparable<ByteString>, Serializable {
private final byte[] bytes;
/** An empty byte string. */
public static final ByteString EMPTY = new ByteString(new byte[0], false);
private static final char[] DIGITS = {
'0', '1', '2', '3', '4', '5', '6', '7',
'8', '9', 'a', 'b', 'c', 'd', 'e', 'f'
};
/**
* Creates a ByteString.
*
* @param bytes Bytes
*/
public ByteString(byte[] bytes) {
this(bytes.clone(), false);
}
// private constructor that does not copy
private ByteString(byte[] bytes, boolean dummy) {
this.bytes = bytes;
}
@Override public int hashCode() {
return Arrays.hashCode(bytes);
}
@Override public boolean equals(Object obj) {
return this == obj
|| obj instanceof ByteString
&& Arrays.equals(bytes, ((ByteString) obj).bytes);
}
public int compareTo(ByteString that) {
final byte[] v1 = bytes;
final byte[] v2 = that.bytes;
final int n = Math.min(v1.length, v2.length);
for (int i = 0; i < n; i++) {
int c1 = v1[i] & 0xff;
int c2 = v2[i] & 0xff;
if (c1 != c2) {
return c1 - c2;
}
}
return v1.length - v2.length;
}
/**
* Returns this byte string in hexadecimal format.
*
* @return Hexadecimal string
*/
@Override public String toString() {
return toString(16);
}
/**
* Returns this byte string in a given base.
*
* @return String in given base
*/
public String toString(int base) {
return toString(bytes, base);
}
/**
* Returns the given byte array in hexadecimal format.
*
* <p>For example, <code>toString(new byte[] {0xDE, 0xAD})</code>
* returns {@code "DEAD"}.</p>
*
* @param bytes Array of bytes
* @param base Base (2 or 16)
* @return String
*/
public static String toString(byte[] bytes, int base) {
char[] chars;
int j = 0;
switch (base) {
case 2:
chars = new char[bytes.length * 8];
for (byte b : bytes) {
chars[j++] = DIGITS[(b & 0x80) >> 7];
chars[j++] = DIGITS[(b & 0x40) >> 6];
chars[j++] = DIGITS[(b & 0x20) >> 5];
chars[j++] = DIGITS[(b & 0x10) >> 4];
chars[j++] = DIGITS[(b & 0x08) >> 3];
chars[j++] = DIGITS[(b & 0x04) >> 2];
chars[j++] = DIGITS[(b & 0x02) >> 1];
chars[j++] = DIGITS[b & 0x01];
}
break;
case 16:
chars = new char[bytes.length * 2];
for (byte b : bytes) {
chars[j++] = DIGITS[(b & 0xF0) >> 4];
chars[j++] = DIGITS[b & 0x0F];
}
break;
default:
throw new IllegalArgumentException("bad base " + base);
}
return String.valueOf(chars, 0, j);
}
/**
* Returns this byte string in Base64 format.
*
* @return Base64 string
*/
public String toBase64String() {
return Base64.encodeBytes(bytes);
}
/**
* Creates a byte string from a hexadecimal or binary string.
*
* <p>For example, <code>of("DEAD", 16)</code>
* returns the same as {@code ByteString(new byte[] {0xDE, 0xAD})}.
*
* @param string Array of bytes
* @param base Base (2 or 16)
* @return String
*/
public static ByteString of(String string, int base) {
final byte[] bytes = parse(string, base);
return new ByteString(bytes, false);
}
/**
* Parses a hexadecimal or binary string to a byte array.
*
* @param string Hexadecimal or binary string
* @param base Base (2 or 16)
* @return Byte array
*/
public static byte[] parse(String string, int base) {
char[] chars = string.toCharArray();
byte[] bytes;
int j = 0;
byte b = 0;
switch (base) {
case 2:
bytes = new byte[chars.length / 8];
for (char c : chars) {
b <<= 1;
if (c == '1') {
b |= 0x1;
}
if (j % 8 == 7) {
bytes[j / 8] = b;
b = 0;
}
++j;
}
break;
case 16:
if (chars.length % 2 != 0) {
throw new IllegalArgumentException("hex string has odd length");
}
bytes = new byte[chars.length / 2];
for (char c : chars) {
b <<= 4;
byte i = decodeHex(c);
b |= i & 0x0F;
if (j % 2 == 1) {
bytes[j / 2] = b;
b = 0;
}
++j;
}
break;
default:
throw new IllegalArgumentException("bad base " + base);
}
return bytes;
}
private static byte decodeHex(char c) {
if (c >= '0' && c <= '9') {
return (byte) (c - '0');
}
if (c >= 'a' && c <= 'f') {
return (byte) (c - 'a' + 10);
}
if (c >= 'A' && c <= 'F') {
return (byte) (c - 'A' + 10);
}
throw new IllegalArgumentException("invalid hex character: " + c);
}
/**
* Creates a byte string from a Base64 string.
*
* @param string Base64 string
* @return Byte string
*/
public static ByteString ofBase64(String string) {
final byte[] bytes = parseBase64(string);
return new ByteString(bytes, false);
}
/**
* Parses a Base64 to a byte array.
*
* @param string Base64 string
* @return Byte array
*/
public static byte[] parseBase64(String string) {
try {
return Base64.decode(string);
} catch (IOException e) {
throw new IllegalArgumentException("bad base64 string", e);
}
}
@SuppressWarnings({
"CloneDoesntCallSuperClone",
"CloneDoesntDeclareCloneNotSupportedException"
})
@Override public Object clone() {
return this;
}
/**
* Returns the number of bytes in this byte string.
*
* @return Length of this byte string
*/
public int length() {
return bytes.length;
}
/**
* Returns the byte at a given position in the byte string.
*
* @param i Index
* @throws IndexOutOfBoundsException if the <code>index</code> argument is
* negative or not less than <code>length()</code>
* @return Byte at given position
*/
public byte byteAt(int i) {
return bytes[i];
}
/**
* Returns a ByteString that consists of a given range.
*
* @param start Start of range
* @param end Position after end of range
* @return Substring
*/
public ByteString substring(int start, int end) {
byte[] bytes = Arrays.copyOfRange(this.bytes, start, end);
return new ByteString(bytes, false);
}
/**
* Returns a ByteString that starts at a given position.
*
* @param start Start of range
* @return Substring
*/
public ByteString substring(int start) {
return substring(start, length());
}
/**
* Returns a copy of the byte array.
*/
@JsonValue
public byte[] getBytes() {
return bytes.clone();
}
/**
* Returns a ByteString consisting of the concatenation of this and another
* string.
*
* @param other Byte string to concatenate
* @return Combined byte string
*/
public ByteString concat(ByteString other) {
int otherLen = other.length();
if (otherLen == 0) {
return this;
}
int len = bytes.length;
byte[] buf = Arrays.copyOf(bytes, len + otherLen);
System.arraycopy(other.bytes, 0, buf, len, other.bytes.length);
return new ByteString(buf, false);
}
/** Returns the position at which {@code seek} first occurs in this byte
* string, or -1 if it does not occur. */
public int indexOf(ByteString seek) {
return indexOf(seek, 0);
}
/** Returns the position at which {@code seek} first occurs in this byte
* string, starting at the specified index, or -1 if it does not occur. */
public int indexOf(ByteString seek, int start) {
iLoop:
for (int i = start; i < bytes.length - seek.bytes.length + 1; i++) {
for (int j = 0;; j++) {
if (j == seek.bytes.length) {
return i;
}
if (bytes[i + j] != seek.bytes[j]) {
continue iLoop;
}
}
}
return -1;
}
/** Returns whether the substring of this ByteString beginning at the
* specified index starts with the specified prefix.
*
* @param prefix The prefix
* @param offset Where to begin looking in this string
*/
public boolean startsWith(ByteString prefix, int offset) {
// Note: offset might be near -1>>>1.
if (offset < 0 || offset > bytes.length - prefix.bytes.length) {
return false;
}
for (int i = offset, j = 0; j < prefix.bytes.length;) {
if (bytes[i++] != prefix.bytes[j++]) {
return false;
}
}
return true;
}
/** Returns whether this ByteString starts with the specified prefix. */
public boolean startsWith(ByteString prefix) {
return startsWith(prefix, 0);
}
/** Returns whether this ByteString ends with the specified suffix. */
public boolean endsWith(ByteString suffix) {
return startsWith(suffix, length() - suffix.length());
}
}
// End ByteString.java