nonapi.io.github.classgraph.utils.StringUtils Maven / Gradle / Ivy
/*
* This file is part of ClassGraph.
*
* Author: Luke Hutchison
*
* Hosted at: https://github.com/classgraph/classgraph
*
* --
*
* The MIT License (MIT)
*
* Copyright (c) 2019 Luke Hutchison
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated
* documentation files (the "Software"), to deal in the Software without restriction, including without
* limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so, subject to the following
* conditions:
*
* The above copyright notice and this permission notice shall be included in all copies or substantial
* portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT
* LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO
* EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
* AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
* OR OTHER DEALINGS IN THE SOFTWARE.
*/
package nonapi.io.github.classgraph.utils;
/**
* File utilities.
*/
public final class StringUtils {
/**
* Constructor.
*/
private StringUtils() {
// Cannot be constructed
}
/**
* Reads the "modified UTF8" format defined in the Java classfile spec, optionally replacing '/' with '.', and
* optionally removing the prefix "L" and the suffix ";".
*
* @param arr
* the array to read the string from
* @param startOffset
* The start offset of the string within the array.
* @param numBytes
* The number of bytes of the UTF8 encoding of the string.
* @param replaceSlashWithDot
* If true, replace '/' with '.'.
* @param stripLSemicolon
* If true, string final ';' character.
* @return The string.
* @throws IllegalArgumentException
* If string could not be parsed.
*/
public static String readString(final byte[] arr, final int startOffset, final int numBytes,
final boolean replaceSlashWithDot, final boolean stripLSemicolon) throws IllegalArgumentException {
if (startOffset < 0L || numBytes < 0 || startOffset + numBytes > arr.length) {
throw new IllegalArgumentException("offset or numBytes out of range");
}
final char[] chars = new char[numBytes];
int byteIdx = 0;
int charIdx = 0;
for (; byteIdx < numBytes; byteIdx++) {
final int c = arr[startOffset + byteIdx] & 0xff;
if (c > 127) {
break;
}
chars[charIdx++] = (char) (replaceSlashWithDot && c == '/' ? '.' : c);
}
while (byteIdx < numBytes) {
final int c = arr[startOffset + byteIdx] & 0xff;
switch (c >> 4) {
case 0:
case 1:
case 2:
case 3:
case 4:
case 5:
case 6:
case 7: {
byteIdx++;
chars[charIdx++] = (char) (replaceSlashWithDot && c == '/' ? '.' : c);
break;
}
case 12:
case 13: {
byteIdx += 2;
if (byteIdx > numBytes) {
throw new IllegalArgumentException("Bad modified UTF8");
}
final int c2 = arr[startOffset + byteIdx - 1];
if ((c2 & 0xc0) != 0x80) {
throw new IllegalArgumentException("Bad modified UTF8");
}
final int c3 = ((c & 0x1f) << 6) | (c2 & 0x3f);
chars[charIdx++] = (char) (replaceSlashWithDot && c3 == '/' ? '.' : c3);
break;
}
case 14: {
byteIdx += 3;
if (byteIdx > numBytes) {
throw new IllegalArgumentException("Bad modified UTF8");
}
final int c2 = arr[startOffset + byteIdx - 2];
final int c3 = arr[startOffset + byteIdx - 1];
if ((c2 & 0xc0) != 0x80 || (c3 & 0xc0) != 0x80) {
throw new IllegalArgumentException("Bad modified UTF8");
}
final int c4 = ((c & 0x0f) << 12) | ((c2 & 0x3f) << 6) | (c3 & 0x3f);
chars[charIdx++] = (char) (replaceSlashWithDot && c4 == '/' ? '.' : c4);
break;
}
default:
throw new IllegalArgumentException("Bad modified UTF8");
}
}
if (charIdx == numBytes && !stripLSemicolon) {
return new String(chars);
} else {
if (stripLSemicolon) {
if (charIdx < 2 || chars[0] != 'L' || chars[charIdx - 1] != ';') {
throw new IllegalArgumentException("Expected string to start with 'L' and end with ';', got \""
+ new String(chars) + "\"");
}
return new String(chars, 1, charIdx - 2);
} else {
return new String(chars, 0, charIdx);
}
}
}
/**
* A replacement for Java 8's String.join().
*
* @param buf
* The buffer to append to.
* @param addAtBeginning
* The token to add at the beginning of the string.
* @param sep
* The separator string.
* @param addAtEnd
* The token to add at the end of the string.
* @param iterable
* The {@link Iterable} to join.
*/
public static void join(final StringBuilder buf, final String addAtBeginning, final String sep,
final String addAtEnd, final Iterable iterable) {
if (!addAtBeginning.isEmpty()) {
buf.append(addAtBeginning);
}
boolean first = true;
for (final Object item : iterable) {
if (first) {
first = false;
} else {
buf.append(sep);
}
buf.append(item == null ? "null" : item.toString());
}
if (!addAtEnd.isEmpty()) {
buf.append(addAtEnd);
}
}
/**
* A replacement for Java 8's String.join().
*
* @param sep
* The separator string.
* @param iterable
* The {@link Iterable} to join.
* @return The string representation of the joined elements.
*/
public static String join(final String sep, final Iterable iterable) {
final StringBuilder buf = new StringBuilder();
join(buf, "", sep, "", iterable);
return buf.toString();
}
/**
* A replacement for Java 8's String.join().
*
* @param sep
* The separator string.
* @param items
* The items to join.
* @return The string representation of the joined items.
*/
public static String join(final String sep, final Object... items) {
final StringBuilder buf = new StringBuilder();
boolean first = true;
for (final Object item : items) {
if (first) {
first = false;
} else {
buf.append(sep);
}
buf.append(item.toString());
}
return buf.toString();
}
}
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