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/*
* Copyright (C) 2007 The Android Open Source Project
*
* 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 org.snapscript.dx.rop.cst;
import org.snapscript.dx.rop.type.Type;
import org.snapscript.dx.util.ByteArray;
import org.snapscript.dx.util.Hex;
/**
* Constants of type {@code CONSTANT_Utf8_info} or {@code CONSTANT_String_info}.
*/
public final class CstString extends TypedConstant {
/**
* {@code non-null;} instance representing {@code ""}, that is, the
* empty string
*/
public static final CstString EMPTY_STRING = new CstString("");
/** {@code non-null;} the UTF-8 value as a string */
private final String string;
/** {@code non-null;} the UTF-8 value as bytes */
private final ByteArray bytes;
/**
* Converts a string into its MUTF-8 form. MUTF-8 differs from normal UTF-8
* in the handling of character '\0' and surrogate pairs.
*
* @param string {@code non-null;} the string to convert
* @return {@code non-null;} the UTF-8 bytes for it
*/
public static byte[] stringToUtf8Bytes(String string) {
int len = string.length();
byte[] bytes = new byte[len * 3]; // Avoid having to reallocate.
int outAt = 0;
for (int i = 0; i < len; i++) {
char c = string.charAt(i);
if ((c != 0) && (c < 0x80)) {
bytes[outAt] = (byte) c;
outAt++;
} else if (c < 0x800) {
bytes[outAt] = (byte) (((c >> 6) & 0x1f) | 0xc0);
bytes[outAt + 1] = (byte) ((c & 0x3f) | 0x80);
outAt += 2;
} else {
bytes[outAt] = (byte) (((c >> 12) & 0x0f) | 0xe0);
bytes[outAt + 1] = (byte) (((c >> 6) & 0x3f) | 0x80);
bytes[outAt + 2] = (byte) ((c & 0x3f) | 0x80);
outAt += 3;
}
}
byte[] result = new byte[outAt];
System.arraycopy(bytes, 0, result, 0, outAt);
return result;
}
/**
* Converts an array of UTF-8 bytes into a string.
*
* @param bytes {@code non-null;} the bytes to convert
* @return {@code non-null;} the converted string
*/
public static String utf8BytesToString(ByteArray bytes) {
int length = bytes.size();
char[] chars = new char[length]; // This is sized to avoid a realloc.
int outAt = 0;
for (int at = 0; length > 0; /*at*/) {
int v0 = bytes.getUnsignedByte(at);
char out;
switch (v0 >> 4) {
case 0x00: case 0x01: case 0x02: case 0x03:
case 0x04: case 0x05: case 0x06: case 0x07: {
// 0XXXXXXX -- single-byte encoding
length--;
if (v0 == 0) {
// A single zero byte is illegal.
return throwBadUtf8(v0, at);
}
out = (char) v0;
at++;
break;
}
case 0x0c: case 0x0d: {
// 110XXXXX -- two-byte encoding
length -= 2;
if (length < 0) {
return throwBadUtf8(v0, at);
}
int v1 = bytes.getUnsignedByte(at + 1);
if ((v1 & 0xc0) != 0x80) {
return throwBadUtf8(v1, at + 1);
}
int value = ((v0 & 0x1f) << 6) | (v1 & 0x3f);
if ((value != 0) && (value < 0x80)) {
/*
* This should have been represented with
* one-byte encoding.
*/
return throwBadUtf8(v1, at + 1);
}
out = (char) value;
at += 2;
break;
}
case 0x0e: {
// 1110XXXX -- three-byte encoding
length -= 3;
if (length < 0) {
return throwBadUtf8(v0, at);
}
int v1 = bytes.getUnsignedByte(at + 1);
if ((v1 & 0xc0) != 0x80) {
return throwBadUtf8(v1, at + 1);
}
int v2 = bytes.getUnsignedByte(at + 2);
if ((v1 & 0xc0) != 0x80) {
return throwBadUtf8(v2, at + 2);
}
int value = ((v0 & 0x0f) << 12) | ((v1 & 0x3f) << 6) |
(v2 & 0x3f);
if (value < 0x800) {
/*
* This should have been represented with one- or
* two-byte encoding.
*/
return throwBadUtf8(v2, at + 2);
}
out = (char) value;
at += 3;
break;
}
default: {
// 10XXXXXX, 1111XXXX -- illegal
return throwBadUtf8(v0, at);
}
}
chars[outAt] = out;
outAt++;
}
return new String(chars, 0, outAt);
}
/**
* Helper for {@link #utf8BytesToString}, which throws the right
* exception for a bogus utf-8 byte.
*
* @param value the byte value
* @param offset the file offset
* @return never
* @throws IllegalArgumentException always thrown
*/
private static String throwBadUtf8(int value, int offset) {
throw new IllegalArgumentException("bad utf-8 byte " + Hex.u1(value) +
" at offset " + Hex.u4(offset));
}
/**
* Constructs an instance from a {@code String}.
*
* @param string {@code non-null;} the UTF-8 value as a string
*/
public CstString(String string) {
if (string == null) {
throw new NullPointerException("string == null");
}
this.string = string.intern();
this.bytes = new ByteArray(stringToUtf8Bytes(string));
}
/**
* Constructs an instance from some UTF-8 bytes.
*
* @param bytes {@code non-null;} array of the UTF-8 bytes
*/
public CstString(ByteArray bytes) {
if (bytes == null) {
throw new NullPointerException("bytes == null");
}
this.bytes = bytes;
this.string = utf8BytesToString(bytes).intern();
}
/** {@inheritDoc} */
@Override
public boolean equals(Object other) {
if (!(other instanceof CstString)) {
return false;
}
return string.equals(((CstString) other).string);
}
/** {@inheritDoc} */
@Override
public int hashCode() {
return string.hashCode();
}
/** {@inheritDoc} */
@Override
protected int compareTo0(Constant other) {
return string.compareTo(((CstString) other).string);
}
/** {@inheritDoc} */
@Override
public String toString() {
return "string{\"" + toHuman() + "\"}";
}
/** {@inheritDoc} */
@Override
public String typeName() {
return "utf8";
}
/** {@inheritDoc} */
@Override
public boolean isCategory2() {
return false;
}
/** {@inheritDoc} */
public String toHuman() {
int len = string.length();
StringBuilder sb = new StringBuilder(len * 3 / 2);
for (int i = 0; i < len; i++) {
char c = string.charAt(i);
if ((c >= ' ') && (c < 0x7f)) {
if ((c == '\'') || (c == '\"') || (c == '\\')) {
sb.append('\\');
}
sb.append(c);
} else if (c <= 0x7f) {
switch (c) {
case '\n': sb.append("\\n"); break;
case '\r': sb.append("\\r"); break;
case '\t': sb.append("\\t"); break;
default: {
/*
* Represent the character as an octal escape.
* If the next character is a valid octal
* digit, disambiguate by using the
* three-digit form.
*/
char nextChar =
(i < (len - 1)) ? string.charAt(i + 1) : 0;
boolean displayZero =
(nextChar >= '0') && (nextChar <= '7');
sb.append('\\');
for (int shift = 6; shift >= 0; shift -= 3) {
char outChar = (char) (((c >> shift) & 7) + '0');
if ((outChar != '0') || displayZero) {
sb.append(outChar);
displayZero = true;
}
}
if (! displayZero) {
// Ironic edge case: The original value was 0.
sb.append('0');
}
break;
}
}
} else {
sb.append("\\u");
sb.append(Character.forDigit(c >> 12, 16));
sb.append(Character.forDigit((c >> 8) & 0x0f, 16));
sb.append(Character.forDigit((c >> 4) & 0x0f, 16));
sb.append(Character.forDigit(c & 0x0f, 16));
}
}
return sb.toString();
}
/**
* Gets the value as a human-oriented string, surrounded by double
* quotes.
*
* @return {@code non-null;} the quoted string
*/
public String toQuoted() {
return '\"' + toHuman() + '\"';
}
/**
* Gets the value as a human-oriented string, surrounded by double
* quotes, but ellipsizes the result if it is longer than the given
* maximum length
*
* @param maxLength {@code >= 5;} the maximum length of the string to return
* @return {@code non-null;} the quoted string
*/
public String toQuoted(int maxLength) {
String string = toHuman();
int length = string.length();
String ellipses;
if (length <= (maxLength - 2)) {
ellipses = "";
} else {
string = string.substring(0, maxLength - 5);
ellipses = "...";
}
return '\"' + string + ellipses + '\"';
}
/**
* Gets the UTF-8 value as a string.
* The returned string is always already interned.
*
* @return {@code non-null;} the UTF-8 value as a string
*/
public String getString() {
return string;
}
/**
* Gets the UTF-8 value as UTF-8 encoded bytes.
*
* @return {@code non-null;} an array of the UTF-8 bytes
*/
public ByteArray getBytes() {
return bytes;
}
/**
* Gets the size of this instance as UTF-8 code points. That is,
* get the number of bytes in the UTF-8 encoding of this instance.
*
* @return {@code >= 0;} the UTF-8 size
*/
public int getUtf8Size() {
return bytes.size();
}
/**
* Gets the size of this instance as UTF-16 code points. That is,
* get the number of 16-bit chars in the UTF-16 encoding of this
* instance. This is the same as the {@code length} of the
* Java {@code String} representation of this instance.
*
* @return {@code >= 0;} the UTF-16 size
*/
public int getUtf16Size() {
return string.length();
}
public Type getType() {
return Type.STRING;
}
}
