StringUtils.java
/*
* Copyright (C) 2009-2022, Google Inc. and others
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Distribution License v. 1.0 which is available at
* https://www.eclipse.org/org/documents/edl-v10.php.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
package org.eclipse.jgit.util;
import java.text.MessageFormat;
import java.util.Collection;
import org.eclipse.jgit.annotations.NonNull;
import org.eclipse.jgit.internal.JGitText;
import org.eclipse.jgit.lib.Constants;
/**
* Miscellaneous string comparison utility methods.
*/
public final class StringUtils {
private static final long KiB = 1024;
private static final long MiB = 1024 * KiB;
private static final long GiB = 1024 * MiB;
private static final char[] LC;
static {
LC = new char['Z' + 1];
for (char c = 0; c < LC.length; c++)
LC[c] = c;
for (char c = 'A'; c <= 'Z'; c++)
LC[c] = (char) ('a' + (c - 'A'));
}
private StringUtils() {
// Do not create instances
}
/**
* Convert the input to lowercase.
* <p>
* This method does not honor the JVM locale, but instead always behaves as
* though it is in the US-ASCII locale. Only characters in the range 'A'
* through 'Z' are converted. All other characters are left as-is, even if
* they otherwise would have a lowercase character equivalent.
*
* @param c
* the input character.
* @return lowercase version of the input.
*/
public static char toLowerCase(char c) {
return c <= 'Z' ? LC[c] : c;
}
/**
* Convert the input string to lower case, according to the "C" locale.
* <p>
* This method does not honor the JVM locale, but instead always behaves as
* though it is in the US-ASCII locale. Only characters in the range 'A'
* through 'Z' are converted, all other characters are left as-is, even if
* they otherwise would have a lowercase character equivalent.
*
* @param in
* the input string. Must not be null.
* @return a copy of the input string, after converting characters in the
* range 'A'..'Z' to 'a'..'z'.
*/
public static String toLowerCase(String in) {
final StringBuilder r = new StringBuilder(in.length());
for (int i = 0; i < in.length(); i++)
r.append(toLowerCase(in.charAt(i)));
return r.toString();
}
/**
* Borrowed from commons-lang <code>StringUtils.capitalize()</code> method.
*
* <p>
* Capitalizes a String changing the first letter to title case as per
* {@link java.lang.Character#toTitleCase(char)}. No other letters are
* changed.
* </p>
* <p>
* A <code>null</code> input String returns <code>null</code>.
* </p>
*
* @param str
* the String to capitalize, may be null
* @return the capitalized String, <code>null</code> if null String input
* @since 4.0
*/
public static String capitalize(String str) {
int strLen;
if (str == null || (strLen = str.length()) == 0) {
return str;
}
return new StringBuilder(strLen)
.append(Character.toTitleCase(str.charAt(0)))
.append(str.substring(1)).toString();
}
/**
* Test if two strings are equal, ignoring case.
* <p>
* This method does not honor the JVM locale, but instead always behaves as
* though it is in the US-ASCII locale.
*
* @param a
* first string to compare.
* @param b
* second string to compare.
* @return true if a equals b
*/
public static boolean equalsIgnoreCase(String a, String b) {
if (References.isSameObject(a, b)) {
return true;
}
if (a.length() != b.length())
return false;
for (int i = 0; i < a.length(); i++) {
if (toLowerCase(a.charAt(i)) != toLowerCase(b.charAt(i)))
return false;
}
return true;
}
/**
* Compare two strings, ignoring case.
* <p>
* This method does not honor the JVM locale, but instead always behaves as
* though it is in the US-ASCII locale.
*
* @param a
* first string to compare.
* @param b
* second string to compare.
* @since 2.0
* @return an int.
*/
public static int compareIgnoreCase(String a, String b) {
for (int i = 0; i < a.length() && i < b.length(); i++) {
int d = toLowerCase(a.charAt(i)) - toLowerCase(b.charAt(i));
if (d != 0)
return d;
}
return a.length() - b.length();
}
/**
* Compare two strings, honoring case.
* <p>
* This method does not honor the JVM locale, but instead always behaves as
* though it is in the US-ASCII locale.
*
* @param a
* first string to compare.
* @param b
* second string to compare.
* @since 2.0
* @return an int.
*/
public static int compareWithCase(String a, String b) {
for (int i = 0; i < a.length() && i < b.length(); i++) {
int d = a.charAt(i) - b.charAt(i);
if (d != 0)
return d;
}
return a.length() - b.length();
}
/**
* Parse a string as a standard Git boolean value. See
* {@link #toBooleanOrNull(String)}.
*
* @param stringValue
* the string to parse.
* @return the boolean interpretation of {@code value}.
* @throws java.lang.IllegalArgumentException
* if {@code value} is not recognized as one of the standard
* boolean names.
*/
public static boolean toBoolean(String stringValue) {
if (stringValue == null)
throw new NullPointerException(JGitText.get().expectedBooleanStringValue);
final Boolean bool = toBooleanOrNull(stringValue);
if (bool == null)
throw new IllegalArgumentException(MessageFormat.format(JGitText.get().notABoolean, stringValue));
return bool.booleanValue();
}
/**
* Parse a string as a standard Git boolean value.
* <p>
* The terms {@code yes}, {@code true}, {@code 1}, {@code on} can all be
* used to mean {@code true}.
* <p>
* The terms {@code no}, {@code false}, {@code 0}, {@code off} can all be
* used to mean {@code false}.
* <p>
* Comparisons ignore case, via {@link #equalsIgnoreCase(String, String)}.
*
* @param stringValue
* the string to parse.
* @return the boolean interpretation of {@code value} or null in case the
* string does not represent a boolean value
*/
public static Boolean toBooleanOrNull(String stringValue) {
if (stringValue == null)
return null;
if (equalsIgnoreCase("yes", stringValue) //$NON-NLS-1$
|| equalsIgnoreCase("true", stringValue) //$NON-NLS-1$
|| equalsIgnoreCase("1", stringValue) //$NON-NLS-1$
|| equalsIgnoreCase("on", stringValue)) //$NON-NLS-1$
return Boolean.TRUE;
else if (equalsIgnoreCase("no", stringValue) //$NON-NLS-1$
|| equalsIgnoreCase("false", stringValue) //$NON-NLS-1$
|| equalsIgnoreCase("0", stringValue) //$NON-NLS-1$
|| equalsIgnoreCase("off", stringValue)) //$NON-NLS-1$
return Boolean.FALSE;
else
return null;
}
/**
* Join a collection of Strings together using the specified separator.
*
* @param parts
* Strings to join
* @param separator
* used to join
* @return a String with all the joined parts
*/
public static String join(Collection<String> parts, String separator) {
return StringUtils.join(parts, separator, separator);
}
/**
* Join a collection of Strings together using the specified separator and a
* lastSeparator which is used for joining the second last and the last
* part.
*
* @param parts
* Strings to join
* @param separator
* separator used to join all but the two last elements
* @param lastSeparator
* separator to use for joining the last two elements
* @return a String with all the joined parts
*/
public static String join(Collection<String> parts, String separator,
String lastSeparator) {
StringBuilder sb = new StringBuilder();
int i = 0;
int lastIndex = parts.size() - 1;
for (String part : parts) {
sb.append(part);
if (i == lastIndex - 1) {
sb.append(lastSeparator);
} else if (i != lastIndex) {
sb.append(separator);
}
i++;
}
return sb.toString();
}
/**
* Appends {@link Constants#DOT_GIT_EXT} unless the given name already ends
* with that suffix.
*
* @param name
* to complete
* @return the name ending with {@link Constants#DOT_GIT_EXT}
* @since 6.1
*/
public static String nameWithDotGit(String name) {
if (name.endsWith(Constants.DOT_GIT_EXT)) {
return name;
}
return name + Constants.DOT_GIT_EXT;
}
/**
* Test if a string is empty or null.
*
* @param stringValue
* the string to check
* @return <code>true</code> if the string is <code>null</code> or empty
*/
public static boolean isEmptyOrNull(String stringValue) {
return stringValue == null || stringValue.length() == 0;
}
/**
* Replace CRLF, CR or LF with a single space.
*
* @param in
* A string with line breaks
* @return in without line breaks
* @since 3.1
*/
public static String replaceLineBreaksWithSpace(String in) {
char[] buf = new char[in.length()];
int o = 0;
for (int i = 0; i < buf.length; ++i) {
char ch = in.charAt(i);
switch (ch) {
case '\r':
if (i + 1 < buf.length && in.charAt(i + 1) == '\n') {
buf[o++] = ' ';
++i;
} else
buf[o++] = ' ';
break;
case '\n':
buf[o++] = ' ';
break;
default:
buf[o++] = ch;
break;
}
}
return new String(buf, 0, o);
}
/**
* Parses a number with optional case-insensitive suffix 'k', 'm', or 'g'
* indicating KiB, MiB, and GiB, respectively. The suffix may follow the
* number with optional separation by one or more blanks.
*
* @param value
* {@link String} to parse; with leading and trailing whitespace
* ignored
* @param positiveOnly
* {@code true} to only accept positive numbers, {@code false} to
* allow negative numbers, too
* @return the value parsed
* @throws NumberFormatException
* if the {@value} is not parseable, or beyond the range of
* {@link Long}
* @throws StringIndexOutOfBoundsException
* if the string is empty or contains only whitespace, or
* contains only the letter 'k', 'm', or 'g'
* @since 6.0
*/
public static long parseLongWithSuffix(@NonNull String value,
boolean positiveOnly)
throws NumberFormatException, StringIndexOutOfBoundsException {
String n = value.strip();
if (n.isEmpty()) {
throw new StringIndexOutOfBoundsException();
}
long mul = 1;
switch (n.charAt(n.length() - 1)) {
case 'g':
case 'G':
mul = GiB;
break;
case 'm':
case 'M':
mul = MiB;
break;
case 'k':
case 'K':
mul = KiB;
break;
default:
break;
}
if (mul > 1) {
n = n.substring(0, n.length() - 1).trim();
}
if (n.isEmpty()) {
throw new StringIndexOutOfBoundsException();
}
long number;
if (positiveOnly) {
number = Long.parseUnsignedLong(n);
if (number < 0) {
throw new NumberFormatException(
MessageFormat.format(JGitText.get().valueExceedsRange,
value, Long.class.getSimpleName()));
}
} else {
number = Long.parseLong(n);
}
if (mul == 1) {
return number;
}
try {
return Math.multiplyExact(mul, number);
} catch (ArithmeticException e) {
NumberFormatException nfe = new NumberFormatException(
e.getLocalizedMessage());
nfe.initCause(e);
throw nfe;
}
}
/**
* Parses a number with optional case-insensitive suffix 'k', 'm', or 'g'
* indicating KiB, MiB, and GiB, respectively. The suffix may follow the
* number with optional separation by blanks.
*
* @param value
* {@link String} to parse; with leading and trailing whitespace
* ignored
* @param positiveOnly
* {@code true} to only accept positive numbers, {@code false} to
* allow negative numbers, too
* @return the value parsed
* @throws NumberFormatException
* if the {@value} is not parseable or beyond the range of
* {@link Integer}
* @throws StringIndexOutOfBoundsException
* if the string is empty or contains only whitespace, or
* contains only the letter 'k', 'm', or 'g'
* @since 6.0
*/
public static int parseIntWithSuffix(@NonNull String value,
boolean positiveOnly)
throws NumberFormatException, StringIndexOutOfBoundsException {
try {
return Math.toIntExact(parseLongWithSuffix(value, positiveOnly));
} catch (ArithmeticException e) {
NumberFormatException nfe = new NumberFormatException(
MessageFormat.format(JGitText.get().valueExceedsRange,
value, Integer.class.getSimpleName()));
nfe.initCause(e);
throw nfe;
}
}
/**
* Formats an integral value as a decimal number with 'k', 'm', or 'g'
* suffix if it is an exact multiple of 1024, otherwise returns the value
* representation as a decimal number without suffix.
*
* @param value
* Value to format
* @return the value's String representation
* @since 6.0
*/
public static String formatWithSuffix(long value) {
if (value >= GiB && (value % GiB) == 0) {
return String.valueOf(value / GiB) + 'g';
}
if (value >= MiB && (value % MiB) == 0) {
return String.valueOf(value / MiB) + 'm';
}
if (value >= KiB && (value % KiB) == 0) {
return String.valueOf(value / KiB) + 'k';
}
return String.valueOf(value);
}
}