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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.
*/
/*
* As per the Apache license requirements, this file has been modified
* from its original state.
*
* Such modifications are Copyright (C) 2010 Ben Gruver, and are released
* under the original license
*/
package com.googlecode.d2j.util;
import java.io.IOException;
import java.io.Writer;
/**
* Constants of type CONSTANT_Utf8_info.
*/
public final class Utf8Utils {
/**
* Converts a string into its Java-style UTF-8 form. Java-style UTF-8 differs from normal UTF-8 in the handling of
* character '\0' and surrogate pairs.
*
* @param string
* non-null; the string to convert
* @return 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;
}
private static char[] tempBuffer = null;
/**
* Converts an array of UTF-8 bytes into a string.
*
* This method uses a global buffer to avoid having to allocate one every time, so it is *not* thread-safe
*
* @param bytes
* non-null; the bytes to convert
* @param start
* the start index of the utf8 string to convert
* @param length
* the length of the utf8 string to convert, not including any null-terminator that might be present
* @return non-null; the converted string
*/
public static String utf8BytesToString(byte[] bytes, int start, int length) {
if (tempBuffer == null || tempBuffer.length < length) {
tempBuffer = new char[length];
}
char[] chars = tempBuffer;
int outAt = 0;
for (int at = start; length > 0; /* at */) {
int v0 = bytes[at] & 0xFF;
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[at + 1] & 0xFF;
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[at + 1] & 0xFF;
if ((v1 & 0xc0) != 0x80) {
return throwBadUtf8(v1, at + 1);
}
int v2 = bytes[at + 2] & 0xFF;
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 " + String.format("%02x", value) + " at offset "
+ String.format("%08x", offset));
}
public static void writeEscapedChar(Writer writer, char c) throws IOException {
if ((c >= ' ') && (c < 0x7f)) {
if ((c == '\'') || (c == '\"') || (c == '\\')) {
writer.write('\\');
}
writer.write(c);
return;
} else if (c <= 0x7f) {
switch (c) {
case '\n':
writer.write("\\n");
return;
case '\r':
writer.write("\\r");
return;
case '\t':
writer.write("\\t");
return;
}
}
writer.write("\\u");
writer.write(Character.forDigit(c >> 12, 16));
writer.write(Character.forDigit((c >> 8) & 0x0f, 16));
writer.write(Character.forDigit((c >> 4) & 0x0f, 16));
writer.write(Character.forDigit(c & 0x0f, 16));
}
public static void writeEscapedString(Writer writer, String value) throws IOException {
for (int i = 0; i < value.length(); i++) {
char c = value.charAt(i);
if ((c >= ' ') && (c < 0x7f)) {
if ((c == '\'') || (c == '\"') || (c == '\\')) {
writer.write('\\');
}
writer.write(c);
continue;
} else if (c <= 0x7f) {
switch (c) {
case '\n':
writer.write("\\n");
continue;
case '\r':
writer.write("\\r");
continue;
case '\t':
writer.write("\\t");
continue;
}
}
writer.write("\\u");
writer.write(Character.forDigit(c >> 12, 16));
writer.write(Character.forDigit((c >> 8) & 0x0f, 16));
writer.write(Character.forDigit((c >> 4) & 0x0f, 16));
writer.write(Character.forDigit(c & 0x0f, 16));
}
}
public static String escapeString(String value) {
int len = value.length();
StringBuilder sb = new StringBuilder(len * 3 / 2);
for (int i = 0; i < len; i++) {
char c = value.charAt(i);
if ((c >= ' ') && (c < 0x7f)) {
if ((c == '\'') || (c == '\"') || (c == '\\')) {
sb.append('\\');
}
sb.append(c);
continue;
} else if (c <= 0x7f) {
switch (c) {
case '\n':
sb.append("\\n");
continue;
case '\r':
sb.append("\\r");
continue;
case '\t':
sb.append("\\t");
continue;
}
}
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();
}
}
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