/*
* Copyright 2014 Square Inc.
*
* 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 okio;
import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import java.io.Serializable;
import java.lang.reflect.Field;
import java.util.Arrays;
import static okio.Util.arrayRangeEquals;
import static okio.Util.checkOffsetAndCount;
/**
* An immutable sequence of bytes.
*
* <p>Byte strings compare lexicographically as a sequence of <strong>unsigned</strong> bytes. That
* is, the byte string {@code ff} sorts after {@code 00}. This is counter to the sort order of the
* corresponding bytes, where {@code -1} sorts before {@code 0}.
*
* <p><strong>Full disclosure:</strong> this class provides untrusted input and output streams with
* raw access to the underlying byte array. A hostile stream implementation could keep a reference
* to the mutable byte string, violating the immutable guarantee of this class. For this reason a
* byte string's immutability guarantee cannot be relied upon for security in applets and other
* environments that run both trusted and untrusted code in the same process.
*/
public class ByteString implements Serializable, Comparable<ByteString> {
static final char[] HEX_DIGITS =
{ '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
private static final long serialVersionUID = 1L;
/** A singleton empty {@code ByteString}. */
public static final ByteString EMPTY = ByteString.of();
final byte[] data;
transient int hashCode; // Lazily computed; 0 if unknown.
transient String utf8; // Lazily computed.
ByteString(byte[] data) {
this.data = data; // Trusted internal constructor doesn't clone data.
}
/**
* Returns a new byte string containing a clone of the bytes of {@code data}.
*/
public static ByteString of(byte... data) {
if (data == null) throw new IllegalArgumentException("data == null");
return new ByteString(data.clone());
}
/**
* Returns a new byte string containing a copy of {@code byteCount} bytes of {@code data} starting
* at {@code offset}.
*/
public static ByteString of(byte[] data, int offset, int byteCount) {
if (data == null) throw new IllegalArgumentException("data == null");
checkOffsetAndCount(data.length, offset, byteCount);
byte[] copy = new byte[byteCount];
System.arraycopy(data, offset, copy, 0, byteCount);
return new ByteString(copy);
}
/** Returns a new byte string containing the {@code UTF-8} bytes of {@code s}. */
public static ByteString encodeUtf8(String s) {
if (s == null) throw new IllegalArgumentException("s == null");
ByteString byteString = new ByteString(s.getBytes(Util.UTF_8));
byteString.utf8 = s;
return byteString;
}
/** Constructs a new {@code String} by decoding the bytes as {@code UTF-8}. */
public String utf8() {
String result = utf8;
// We don't care if we double-allocate in racy code.
return result != null ? result : (utf8 = new String(data, Util.UTF_8));
}
/**
* Returns this byte string encoded as <a
* href="http://www.ietf.org/rfc/rfc2045.txt">Base64</a>. In violation of the
* RFC, the returned string does not wrap lines at 76 columns.
*/
public String base64() {
return Base64.encode(data);
}
/** Returns the MD5 hash of this byte string. */
public ByteString md5() {
return digest("MD5");
}
/** Returns the SHA-256 hash of this byte string. */
public ByteString sha256() {
return digest("SHA-256");
}
private ByteString digest(String digest) {
return ByteString.of(MessageDigest.digest(digest, data));
}
/**
* Returns this byte string encoded as <a href="http://www.ietf.org/rfc/rfc4648.txt">URL-safe
* Base64</a>.
*/
public String base64Url() {
return Base64.encodeUrl(data);
}
/**
* Decodes the Base64-encoded bytes and returns their value as a byte string.
* Returns null if {@code base64} is not a Base64-encoded sequence of bytes.
*/
public static ByteString decodeBase64(String base64) {
if (base64 == null) throw new IllegalArgumentException("base64 == null");
byte[] decoded = Base64.decode(base64);
return decoded != null ? new ByteString(decoded) : null;
}
/** Returns this byte string encoded in hexadecimal. */
public String hex() {
char[] result = new char[data.length * 2];
int c = 0;
for (byte b : data) {
result[c++] = HEX_DIGITS[(b >> 4) & 0xf];
result[c++] = HEX_DIGITS[b & 0xf];
}
return new String(result);
}
/** Decodes the hex-encoded bytes and returns their value a byte string. */
public static ByteString decodeHex(String hex) {
if (hex == null) throw new IllegalArgumentException("hex == null");
if (hex.length() % 2 != 0) throw new IllegalArgumentException("Unexpected hex string: " + hex);
byte[] result = new byte[hex.length() / 2];
for (int i = 0; i < result.length; i++) {
int d1 = decodeHexDigit(hex.charAt(i * 2)) << 4;
int d2 = decodeHexDigit(hex.charAt(i * 2 + 1));
result[i] = (byte) (d1 + d2);
}
return of(result);
}
private static int decodeHexDigit(char c) {
if (c >= '0' && c <= '9') return c - '0';
if (c >= 'a' && c <= 'f') return c - 'a' + 10;
if (c >= 'A' && c <= 'F') return c - 'A' + 10;
throw new IllegalArgumentException("Unexpected hex digit: " + c);
}
/**
* Reads {@code count} bytes from {@code in} and returns the result.
*
* @throws java.io.EOFException if {@code in} has fewer than {@code count}
* bytes to read.
*/
public static ByteString read(InputStream in, int byteCount) throws IOException {
if (in == null) throw new IllegalArgumentException("in == null");
if (byteCount < 0) throw new IllegalArgumentException("byteCount < 0: " + byteCount);
byte[] result = new byte[byteCount];
for (int offset = 0, read; offset < byteCount; offset += read) {
read = in.read(result, offset, byteCount - offset);
if (read == -1) throw new EOFException();
}
return new ByteString(result);
}
/**
* Returns a byte string equal to this byte string, but with the bytes 'A'
* through 'Z' replaced with the corresponding byte in 'a' through 'z'.
* Returns this byte string if it contains no bytes in 'A' through 'Z'.
*/
public ByteString toAsciiLowercase() {
// Search for an uppercase character. If we don't find one, return this.
for (int i = 0; i < data.length; i++) {
byte c = data[i];
if (c < 'A' || c > 'Z') continue;
// If we reach this point, this string is not not lowercase. Create and
// return a new byte string.
byte[] lowercase = data.clone();
lowercase[i++] = (byte) (c - ('A' - 'a'));
for (; i < lowercase.length; i++) {
c = lowercase[i];
if (c < 'A' || c > 'Z') continue;
lowercase[i] = (byte) (c - ('A' - 'a'));
}
return new ByteString(lowercase);
}
return this;
}
/**
* Returns a byte string equal to this byte string, but with the bytes 'a'
* through 'z' replaced with the corresponding byte in 'A' through 'Z'.
* Returns this byte string if it contains no bytes in 'a' through 'z'.
*/
public ByteString toAsciiUppercase() {
// Search for an lowercase character. If we don't find one, return this.
for (int i = 0; i < data.length; i++) {
byte c = data[i];
if (c < 'a' || c > 'z') continue;
// If we reach this point, this string is not not uppercase. Create and
// return a new byte string.
byte[] lowercase = data.clone();
lowercase[i++] = (byte) (c - ('a' - 'A'));
for (; i < lowercase.length; i++) {
c = lowercase[i];
if (c < 'a' || c > 'z') continue;
lowercase[i] = (byte) (c - ('a' - 'A'));
}
return new ByteString(lowercase);
}
return this;
}
/**
* Returns a byte string that is a substring of this byte string, beginning at the specified
* index until the end of this string. Returns this byte string if {@code beginIndex} is 0.
*/
public ByteString substring(int beginIndex) {
return substring(beginIndex, data.length);
}
/**
* Returns a byte string that is a substring of this byte string, beginning at the specified
* {@code beginIndex} and ends at the specified {@code endIndex}. Returns this byte string if
* {@code beginIndex} is 0 and {@code endIndex} is the length of this byte string.
*/
public ByteString substring(int beginIndex, int endIndex) {
if (beginIndex < 0) throw new IllegalArgumentException("beginIndex < 0");
if (endIndex > data.length) {
throw new IllegalArgumentException("endIndex > length(" + data.length + ")");
}
int subLen = endIndex - beginIndex;
if (subLen < 0) throw new IllegalArgumentException("endIndex < beginIndex");
if ((beginIndex == 0) && (endIndex == data.length)) {
return this;
}
byte[] copy = new byte[subLen];
System.arraycopy(data, beginIndex, copy, 0, subLen);
return new ByteString(copy);
}
/** Returns the byte at {@code pos}. */
public byte getByte(int pos) {
return data[pos];
}
/**
* Returns the number of bytes in this ByteString.
*/
public int size() {
return data.length;
}
/**
* Returns a byte array containing a copy of the bytes in this {@code ByteString}.
*/
public byte[] toByteArray() {
return data.clone();
}
/** Writes the contents of this byte string to {@code out}. */
public void write(OutputStream out) throws IOException {
if (out == null) throw new IllegalArgumentException("out == null");
out.write(data);
}
/** Writes the contents of this byte string to {@code buffer}. */
void write(Buffer buffer) {
buffer.write(data, 0, data.length);
}
/**
* Returns true if the bytes of this in {@code [offset..offset+byteCount)} equal the bytes of
* {@code other} in {@code [otherOffset..otherOffset+byteCount)}. Returns false if either range is
* out of bounds.
*/
public boolean rangeEquals(int offset, ByteString other, int otherOffset, int byteCount) {
return other.rangeEquals(otherOffset, this.data, offset, byteCount);
}
/**
* Returns true if the bytes of this in {@code [offset..offset+byteCount)} equal the bytes of
* {@code other} in {@code [otherOffset..otherOffset+byteCount)}. Returns false if either range is
* out of bounds.
*/
public boolean rangeEquals(int offset, byte[] other, int otherOffset, int byteCount) {
return offset <= data.length - byteCount
&& otherOffset <= other.length - byteCount
&& arrayRangeEquals(data, offset, other, otherOffset, byteCount);
}
@Override public boolean equals(Object o) {
if (o == this) return true;
return o instanceof ByteString
&& ((ByteString) o).size() == data.length
&& ((ByteString) o).rangeEquals(0, data, 0, data.length);
}
@Override public int hashCode() {
int result = hashCode;
return result != 0 ? result : (hashCode = Arrays.hashCode(data));
}
@Override public int compareTo(ByteString byteString) {
int sizeA = size();
int sizeB = byteString.size();
for (int i = 0, size = Math.min(sizeA, sizeB); i < size; i++) {
int byteA = getByte(i) & 0xff;
int byteB = byteString.getByte(i) & 0xff;
if (byteA == byteB) continue;
return byteA < byteB ? -1 : 1;
}
if (sizeA == sizeB) return 0;
return sizeA < sizeB ? -1 : 1;
}
@Override public String toString() {
if (data.length == 0) {
return "ByteString[size=0]";
}
if (data.length <= 16) {
return String.format("ByteString[size=%s data=%s]", data.length, hex());
}
return String.format("ByteString[size=%s md5=%s]", data.length, md5().hex());
}
private void readObject(ObjectInputStream in) throws IOException {
int dataLength = in.readInt();
ByteString byteString = ByteString.read(in, dataLength);
try {
Field field = ByteString.class.getDeclaredField("data");
field.setAccessible(true);
field.set(this, byteString.data);
} catch (NoSuchFieldException e) {
throw new AssertionError();
} catch (IllegalAccessException e) {
throw new AssertionError();
}
}
private void writeObject(ObjectOutputStream out) throws IOException {
out.writeInt(data.length);
out.write(data);
}
}