Package com.ibm.icu.impl
Class Utility
- java.lang.Object
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- com.ibm.icu.impl.Utility
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public final class Utility extends java.lang.Object
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Field Summary
Fields Modifier and Type Field Description private static char
APOSTROPHE
private static char
BACKSLASH
(package private) static char[]
DIGITS
private static char
ESCAPE
The ESCAPE character is used during run-length encoding.(package private) static byte
ESCAPE_BYTE
The ESCAPE_BYTE character is used during run-length encoding.(package private) static char[]
HEX_DIGIT
static java.lang.String
LINE_SEPARATOR
private static int
MAGIC_UNSIGNED
private static char[]
UNESCAPE_MAP
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Constructor Summary
Constructors Constructor Description Utility()
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Method Summary
All Methods Static Methods Concrete Methods Modifier and Type Method Description private static int
_digit16(int c)
private static int
_digit8(int c)
static int
addExact(int x, int y)
This implementation is equivalent to Java 8+ Math#addExact(int, int)private static <T extends java.lang.Appendable>
voidappendEncodedByte(T buffer, byte value, byte[] state)
Append a byte to the given Appendable, packing two bytes into each character.private static <T extends java.lang.Appendable>
voidappendInt(T buffer, int value)
static <T extends java.lang.Appendable>
TappendNumber(T result, int n, int radix, int minDigits)
Append a number to the given Appendable in the given radix.static <A extends java.lang.Appendable>
AappendTo(java.lang.CharSequence string, A appendable)
Appends a CharSequence to an Appendable, converting IOException to ICUUncheckedIOException.static void
appendToRule(java.lang.StringBuffer rule, int c, boolean isLiteral, boolean escapeUnprintable, java.lang.StringBuffer quoteBuf)
Append a character to a rule that is being built up.static void
appendToRule(java.lang.StringBuffer rule, UnicodeMatcher matcher, boolean escapeUnprintable, java.lang.StringBuffer quoteBuf)
Given a matcher reference, which may be null, append its pattern as a literal to the given rule.static void
appendToRule(java.lang.StringBuffer rule, java.lang.String text, boolean isLiteral, boolean escapeUnprintable, java.lang.StringBuffer quoteBuf)
Append the given string to the rule.static boolean
arrayEquals(byte[] source, java.lang.Object target)
static boolean
arrayEquals(double[] source, java.lang.Object target)
Convenience utility to compare two double[]s Ought to be in Systemstatic boolean
arrayEquals(int[] source, java.lang.Object target)
Convenience utility to compare two int[]s Ought to be in Systemstatic boolean
arrayEquals(java.lang.Object[] source, java.lang.Object target)
Convenience utility to compare two Object[]s.static boolean
arrayEquals(java.lang.Object source, java.lang.Object target)
Convenience utility to compare two Object[]s Ought to be in Systemstatic boolean
arrayRegionMatches(byte[] source, int sourceStart, byte[] target, int targetStart, int len)
static boolean
arrayRegionMatches(char[] source, int sourceStart, char[] target, int targetStart, int len)
Convenience utility to compare two Object[]s Ought to be in System.static boolean
arrayRegionMatches(double[] source, int sourceStart, double[] target, int targetStart, int len)
Convenience utility to compare two arrays of doubles.static boolean
arrayRegionMatches(int[] source, int sourceStart, int[] target, int targetStart, int len)
Convenience utility to compare two int[]s.static boolean
arrayRegionMatches(java.lang.Object[] source, int sourceStart, java.lang.Object[] target, int targetStart, int len)
Convenience utility to compare two Object[]s Ought to be in System.static java.lang.String
arrayToRLEString(byte[] a)
Construct a string representing a byte array.static java.lang.String
arrayToRLEString(char[] a)
Construct a string representing a char array.static java.lang.String
arrayToRLEString(int[] a)
Construct a string representing an int array.static java.lang.String
arrayToRLEString(short[] a)
Construct a string representing a short array.static boolean
charSequenceEquals(java.lang.CharSequence a, java.lang.CharSequence b)
Returns whether the chars in the two CharSequences are equal.static int
charSequenceHashCode(java.lang.CharSequence value)
Returns a hash code for a CharSequence that is equivalent to calling charSequence.toString().hashCode()static <T extends java.lang.Comparable<T>>
intcheckCompare(T a, T b)
Convenience utility.static int
checkHash(java.lang.Object a)
Convenience utility.private static int
codePointAndLength(int c, int length)
private static int
codePointAndLength(int c, int start, int limit)
static int
compareUnsigned(int source, int target)
Compares 2 unsigned integersstatic int
cpFromCodePointAndLength(int cpAndLength)
private static <T extends java.lang.Appendable>
voidencodeRun(T buffer, byte value, int length, byte[] state)
Encode a run, possibly a degenerate run (of < 4 values).private static <T extends java.lang.Appendable>
voidencodeRun(T buffer, int value, int length)
Encode a run, possibly a degenerate run (of < 4 values).private static <T extends java.lang.Appendable>
voidencodeRun(T buffer, short value, int length)
Encode a run, possibly a degenerate run (of < 4 values).static java.lang.String
escape(java.lang.String s)
Convert characters outside the range U+0020 to U+007F to Unicode escapes, and convert backslash to a double backslash.static <T extends java.lang.Appendable>
Tescape(T result, int c)
Escapes one code point usinguxxxx notation for U+0000 to U+FFFF and Uxxxxxxxx for U+10000 and above. static <T extends java.lang.Appendable>
booleanescapeUnprintable(T result, int c)
Escapes one unprintable code point usinguxxxx notation for U+0000 to U+FFFF and Uxxxxxxxx for U+10000 and above. static java.lang.String
format1ForSource(java.lang.String s)
Format a String for representation in a source file.static java.lang.String
formatForSource(java.lang.String s)
Format a String for representation in a source file.static java.lang.String
fromHex(java.lang.String string, int minLength, java.lang.String separator)
Parse a list of hex numbers and return a stringstatic java.lang.String
fromHex(java.lang.String string, int minLength, java.util.regex.Pattern separator)
Parse a list of hex numbers and return a string(package private) static int
getInt(java.lang.String s, int i)
static java.lang.String
hex(byte[] o, int start, int end, java.lang.String separator)
static java.lang.String
hex(long ch)
Convert a char to 4 hex uppercase digits.static java.lang.String
hex(long i, int places)
Supplies a zero-padded hex representation of an integer (without 0x)static java.lang.String
hex(java.lang.CharSequence s)
Convert a string to comma-separated groups of 4 hex uppercase digits.static <S extends java.lang.CharSequence>
java.lang.Stringhex(S s, int width, S separator)
Convert a string to comma-separated groups of 4 hex uppercase digits.static <S extends java.lang.CharSequence,U extends java.lang.CharSequence,T extends java.lang.Appendable>
Thex(S s, int width, U separator, boolean useCodePoints, T result)
Convert a string to separated groups of hex uppercase digits.static byte
highBit(int n)
Find the highest bit in a positive integer.static boolean
isUnprintable(int c)
Return true if the character is NOT printable ASCII.static java.lang.String
joinStrings(java.lang.CharSequence delimiter, java.lang.Iterable<? extends java.lang.CharSequence> elements)
Java 8+ String#join(CharSequence, Iterable extends CharSequence>) compatible method for Java 7 env.static int
lengthFromCodePointAndLength(int cpAndLength)
static int
lookup(java.lang.String source, java.lang.String[] target)
Look up a given string in a string array.static boolean
parseChar(java.lang.String id, int[] pos, char ch)
Parse a single non-whitespace character 'ch', optionally preceded by whitespace.static int
parseInteger(java.lang.String rule, int[] pos, int limit)
Parse an integer at pos, either of the form \d+ or of the form 0x[0-9A-Fa-f]+ or 0[0-7]+, that is, in standard decimal, hex, or octal format.static int
parseNumber(java.lang.String text, int[] pos, int radix)
Parse an unsigned 31-bit integer at the given offset.static int
parsePattern(java.lang.String rule, int pos, int limit, java.lang.String pattern, int[] parsedInts)
Parse a pattern string starting at offset pos.static int
parsePattern(java.lang.String pat, Replaceable text, int index, int limit)
Parse a pattern string within the given Replaceable and a parsing pattern.static java.lang.String
parseUnicodeIdentifier(java.lang.String str, int[] pos)
Parse a Unicode identifier from the given string at the given position.static int
quotedIndexOf(java.lang.String text, int start, int limit, java.lang.String setOfChars)
Returns the index of the first character in a set, ignoring quoted text.private static <T extends java.lang.Appendable>
voidrecursiveAppendNumber(T result, int n, int radix, int minDigits)
Append the digits of a positive integer to the givenAppendable
in the given radix.static java.lang.String
repeat(java.lang.String s, int count)
Utility to duplicate a string count timesstatic byte[]
RLEStringToByteArray(java.lang.String s)
Construct an array of bytes from a run-length encoded string.static char[]
RLEStringToCharArray(java.lang.String s)
Construct an array of shorts from a run-length encoded string.static int[]
RLEStringToIntArray(java.lang.String s)
Construct an array of ints from a run-length encoded string.static short[]
RLEStringToShortArray(java.lang.String s)
Construct an array of shorts from a run-length encoded string.static boolean
sameObjects(java.lang.Object a, java.lang.Object b)
Trivial reference equality.static boolean
shouldAlwaysBeEscaped(int c)
static java.lang.String[]
split(java.lang.String s, char divider)
Split a string into pieces based on the given divider characterstatic void
split(java.lang.String s, char divider, java.lang.String[] output)
Split a string into pieces based on the given divider characterstatic java.lang.String[]
splitString(java.lang.String src, java.lang.String target)
static java.lang.String[]
splitWhitespace(java.lang.String src)
Split the string at runs of ascii whitespace characters.static java.lang.String
unescape(java.lang.CharSequence s)
Convert all escapes in a given string using unescapeAndLengthAt().static int
unescapeAndLengthAt(java.lang.CharSequence s, int offset)
Converts an escape to a code point value.private static int
unescapeAndLengthAt(java.lang.CharSequence s, int offset, int length)
static java.lang.String
unescapeLeniently(java.lang.CharSequence s)
Convert all escapes in a given string using unescapeAndLengthAt().static java.lang.String
valueOf(int[] source)
Utility method to take a int[] containing codepoints and return a string representation with code units.
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Field Detail
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APOSTROPHE
private static final char APOSTROPHE
- See Also:
- Constant Field Values
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BACKSLASH
private static final char BACKSLASH
- See Also:
- Constant Field Values
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MAGIC_UNSIGNED
private static final int MAGIC_UNSIGNED
- See Also:
- Constant Field Values
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ESCAPE
private static final char ESCAPE
The ESCAPE character is used during run-length encoding. It signals a run of identical chars.- See Also:
- Constant Field Values
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ESCAPE_BYTE
static final byte ESCAPE_BYTE
The ESCAPE_BYTE character is used during run-length encoding. It signals a run of identical bytes.- See Also:
- Constant Field Values
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LINE_SEPARATOR
public static java.lang.String LINE_SEPARATOR
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HEX_DIGIT
static final char[] HEX_DIGIT
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UNESCAPE_MAP
private static final char[] UNESCAPE_MAP
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DIGITS
static final char[] DIGITS
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Method Detail
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arrayEquals
public static final boolean arrayEquals(java.lang.Object[] source, java.lang.Object target)
Convenience utility to compare two Object[]s. Ought to be in System
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arrayEquals
public static final boolean arrayEquals(int[] source, java.lang.Object target)
Convenience utility to compare two int[]s Ought to be in System
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arrayEquals
public static final boolean arrayEquals(double[] source, java.lang.Object target)
Convenience utility to compare two double[]s Ought to be in System
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arrayEquals
public static final boolean arrayEquals(byte[] source, java.lang.Object target)
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arrayEquals
public static final boolean arrayEquals(java.lang.Object source, java.lang.Object target)
Convenience utility to compare two Object[]s Ought to be in System
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arrayRegionMatches
public static final boolean arrayRegionMatches(java.lang.Object[] source, int sourceStart, java.lang.Object[] target, int targetStart, int len)
Convenience utility to compare two Object[]s Ought to be in System.- Parameters:
len
- the length to compare. The start indices and start+len must be valid.
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arrayRegionMatches
public static final boolean arrayRegionMatches(char[] source, int sourceStart, char[] target, int targetStart, int len)
Convenience utility to compare two Object[]s Ought to be in System.- Parameters:
len
- the length to compare. The start indices and start+len must be valid.
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arrayRegionMatches
public static final boolean arrayRegionMatches(int[] source, int sourceStart, int[] target, int targetStart, int len)
Convenience utility to compare two int[]s.- Parameters:
len
- the length to compare. The start indices and start+len must be valid. Ought to be in System
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arrayRegionMatches
public static final boolean arrayRegionMatches(double[] source, int sourceStart, double[] target, int targetStart, int len)
Convenience utility to compare two arrays of doubles.- Parameters:
len
- the length to compare. The start indices and start+len must be valid. Ought to be in System
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arrayRegionMatches
public static final boolean arrayRegionMatches(byte[] source, int sourceStart, byte[] target, int targetStart, int len)
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sameObjects
public static final boolean sameObjects(java.lang.Object a, java.lang.Object b)
Trivial reference equality. This method should help document that we really want == not equals(), and to have a single place to suppress warnings from static analysis tools.
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checkCompare
public static <T extends java.lang.Comparable<T>> int checkCompare(T a, T b)
Convenience utility. Does null checks on objects, then calls compare.
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checkHash
public static int checkHash(java.lang.Object a)
Convenience utility. Does null checks on object, then calls hashCode.
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arrayToRLEString
public static final java.lang.String arrayToRLEString(int[] a)
Construct a string representing an int array. Use run-length encoding. A character represents itself, unless it is the ESCAPE character. Then the following notations are possible: ESCAPE ESCAPE ESCAPE literal ESCAPE n c n instances of character c Since an encoded run occupies 3 characters, we only encode runs of 4 or more characters. Thus we have n > 0 and n != ESCAPE and n <= 0xFFFF. If we encounter a run where n == ESCAPE, we represent this as: c ESCAPE n-1 c The ESCAPE value is chosen so as not to collide with commonly seen values.
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arrayToRLEString
public static final java.lang.String arrayToRLEString(short[] a)
Construct a string representing a short array. Use run-length encoding. A character represents itself, unless it is the ESCAPE character. Then the following notations are possible: ESCAPE ESCAPE ESCAPE literal ESCAPE n c n instances of character c Since an encoded run occupies 3 characters, we only encode runs of 4 or more characters. Thus we have n > 0 and n != ESCAPE and n <= 0xFFFF. If we encounter a run where n == ESCAPE, we represent this as: c ESCAPE n-1 c The ESCAPE value is chosen so as not to collide with commonly seen values.
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arrayToRLEString
public static final java.lang.String arrayToRLEString(char[] a)
Construct a string representing a char array. Use run-length encoding. A character represents itself, unless it is the ESCAPE character. Then the following notations are possible: ESCAPE ESCAPE ESCAPE literal ESCAPE n c n instances of character c Since an encoded run occupies 3 characters, we only encode runs of 4 or more characters. Thus we have n > 0 and n != ESCAPE and n <= 0xFFFF. If we encounter a run where n == ESCAPE, we represent this as: c ESCAPE n-1 c The ESCAPE value is chosen so as not to collide with commonly seen values.
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arrayToRLEString
public static final java.lang.String arrayToRLEString(byte[] a)
Construct a string representing a byte array. Use run-length encoding. Two bytes are packed into a single char, with a single extra zero byte at the end if needed. A byte represents itself, unless it is the ESCAPE_BYTE. Then the following notations are possible: ESCAPE_BYTE ESCAPE_BYTE ESCAPE_BYTE literal ESCAPE_BYTE n b n instances of byte b Since an encoded run occupies 3 bytes, we only encode runs of 4 or more bytes. Thus we have n > 0 and n != ESCAPE_BYTE and n <= 0xFF. If we encounter a run where n == ESCAPE_BYTE, we represent this as: b ESCAPE_BYTE n-1 b The ESCAPE_BYTE value is chosen so as not to collide with commonly seen values.
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encodeRun
private static final <T extends java.lang.Appendable> void encodeRun(T buffer, int value, int length)
Encode a run, possibly a degenerate run (of < 4 values).- Parameters:
length
- The length of the run; must be > 0 && <= 0xFFFF.
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appendInt
private static final <T extends java.lang.Appendable> void appendInt(T buffer, int value)
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encodeRun
private static final <T extends java.lang.Appendable> void encodeRun(T buffer, short value, int length)
Encode a run, possibly a degenerate run (of < 4 values).- Parameters:
length
- The length of the run; must be > 0 && <= 0xFFFF.
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encodeRun
private static final <T extends java.lang.Appendable> void encodeRun(T buffer, byte value, int length, byte[] state)
Encode a run, possibly a degenerate run (of < 4 values).- Parameters:
length
- The length of the run; must be > 0 && <= 0xFF.
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appendEncodedByte
private static final <T extends java.lang.Appendable> void appendEncodedByte(T buffer, byte value, byte[] state)
Append a byte to the given Appendable, packing two bytes into each character. The state parameter maintains intermediary data between calls.- Parameters:
state
- A two-element array, with state[0] == 0 if this is the first byte of a pair, or state[0] != 0 if this is the second byte of a pair, in which case state[1] is the first byte.
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RLEStringToIntArray
public static final int[] RLEStringToIntArray(java.lang.String s)
Construct an array of ints from a run-length encoded string.
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getInt
static final int getInt(java.lang.String s, int i)
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RLEStringToShortArray
public static final short[] RLEStringToShortArray(java.lang.String s)
Construct an array of shorts from a run-length encoded string.
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RLEStringToCharArray
public static final char[] RLEStringToCharArray(java.lang.String s)
Construct an array of shorts from a run-length encoded string.
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RLEStringToByteArray
public static final byte[] RLEStringToByteArray(java.lang.String s)
Construct an array of bytes from a run-length encoded string.
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formatForSource
public static final java.lang.String formatForSource(java.lang.String s)
Format a String for representation in a source file. This includes breaking it into lines and escaping characters using octal notation when necessary (control characters and double quotes).
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format1ForSource
public static final java.lang.String format1ForSource(java.lang.String s)
Format a String for representation in a source file. Like formatForSource but does not do line breaking.
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escape
public static final java.lang.String escape(java.lang.String s)
Convert characters outside the range U+0020 to U+007F to Unicode escapes, and convert backslash to a double backslash.
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_digit8
private static final int _digit8(int c)
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_digit16
private static final int _digit16(int c)
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unescapeAndLengthAt
public static int unescapeAndLengthAt(java.lang.CharSequence s, int offset)
Converts an escape to a code point value. We attempt to parallel the icu4c unescapeAt() function. This function returns an integer with both the code point (bits 28..8) and the length of the escape sequence (bits 7..0). offset+length is the index after the escape sequence.- Parameters:
offset
- the offset to the character after the backslash.- Returns:
- the code point and length, or -1 on error.
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unescapeAndLengthAt
private static int unescapeAndLengthAt(java.lang.CharSequence s, int offset, int length)
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codePointAndLength
private static int codePointAndLength(int c, int length)
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codePointAndLength
private static int codePointAndLength(int c, int start, int limit)
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cpFromCodePointAndLength
public static int cpFromCodePointAndLength(int cpAndLength)
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lengthFromCodePointAndLength
public static int lengthFromCodePointAndLength(int cpAndLength)
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unescape
public static java.lang.String unescape(java.lang.CharSequence s)
Convert all escapes in a given string using unescapeAndLengthAt().- Throws:
java.lang.IllegalArgumentException
- if an invalid escape is seen.
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unescapeLeniently
public static java.lang.String unescapeLeniently(java.lang.CharSequence s)
Convert all escapes in a given string using unescapeAndLengthAt(). Leave invalid escape sequences unchanged.
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hex
public static java.lang.String hex(long ch)
Convert a char to 4 hex uppercase digits. E.g., hex('a') => "0041".
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hex
public static java.lang.String hex(long i, int places)
Supplies a zero-padded hex representation of an integer (without 0x)
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hex
public static java.lang.String hex(java.lang.CharSequence s)
Convert a string to comma-separated groups of 4 hex uppercase digits. E.g., hex('ab') => "0041,0042".
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hex
public static <S extends java.lang.CharSequence,U extends java.lang.CharSequence,T extends java.lang.Appendable> T hex(S s, int width, U separator, boolean useCodePoints, T result)
Convert a string to separated groups of hex uppercase digits. E.g., hex('ab'...) => "0041,0042". Append the output to the given Appendable.
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hex
public static java.lang.String hex(byte[] o, int start, int end, java.lang.String separator)
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hex
public static <S extends java.lang.CharSequence> java.lang.String hex(S s, int width, S separator)
Convert a string to comma-separated groups of 4 hex uppercase digits. E.g., hex('ab') => "0041,0042".
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split
public static void split(java.lang.String s, char divider, java.lang.String[] output)
Split a string into pieces based on the given divider character- Parameters:
s
- the string to splitdivider
- the character on which to split. Occurrences of this character are not included in the outputoutput
- an array to receive the substrings between instances of divider. It must be large enough on entry to accommodate all output. Adjacent instances of the divider character will place empty strings into output. Before returning, output is padded out with empty strings.
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split
public static java.lang.String[] split(java.lang.String s, char divider)
Split a string into pieces based on the given divider character- Parameters:
s
- the string to splitdivider
- the character on which to split. Occurrences of this character are not included in the output- Returns:
- output an array to receive the substrings between instances of divider. Adjacent instances of the divider character will place empty strings into output.
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lookup
public static int lookup(java.lang.String source, java.lang.String[] target)
Look up a given string in a string array. Returns the index at which the first occurrence of the string was found in the array, or -1 if it was not found.- Parameters:
source
- the string to search fortarget
- the array of zero or more strings in which to look for source- Returns:
- the index of target at which source first occurs, or -1 if not found
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parseChar
public static boolean parseChar(java.lang.String id, int[] pos, char ch)
Parse a single non-whitespace character 'ch', optionally preceded by whitespace.- Parameters:
id
- the string to be parsedpos
- INPUT-OUTPUT parameter. On input, pos[0] is the offset of the first character to be parsed. On output, pos[0] is the index after the last parsed character. If the parse fails, pos[0] will be unchanged.ch
- the non-whitespace character to be parsed.- Returns:
- true if 'ch' is seen preceded by zero or more whitespace characters.
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parsePattern
public static int parsePattern(java.lang.String rule, int pos, int limit, java.lang.String pattern, int[] parsedInts)
Parse a pattern string starting at offset pos. Keywords are matched case-insensitively. Spaces may be skipped and may be optional or required. Integer values may be parsed, and if they are, they will be returned in the given array. If successful, the offset of the next non-space character is returned. On failure, -1 is returned.- Parameters:
pattern
- must only contain lowercase characters, which will match their uppercase equivalents as well. A space character matches one or more required spaces. A '~' character matches zero or more optional spaces. A '#' character matches an integer and stores it in parsedInts, which the caller must ensure has enough capacity.parsedInts
- array to receive parsed integers. Caller must ensure that parsedInts.length is >= the number of '#' signs in 'pattern'.- Returns:
- the position after the last character parsed, or -1 if the parse failed
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parsePattern
public static int parsePattern(java.lang.String pat, Replaceable text, int index, int limit)
Parse a pattern string within the given Replaceable and a parsing pattern. Characters are matched literally and case-sensitively except for the following special characters: ~ zero or more Pattern_White_Space chars If end of pattern is reached with all matches along the way, pos is advanced to the first unparsed index and returned. Otherwise -1 is returned.- Parameters:
pat
- pattern that controls parsingtext
- text to be parsed, starting at indexindex
- offset to first character to parselimit
- offset after last character to parse- Returns:
- index after last parsed character, or -1 on parse failure.
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parseInteger
public static int parseInteger(java.lang.String rule, int[] pos, int limit)
Parse an integer at pos, either of the form \d+ or of the form 0x[0-9A-Fa-f]+ or 0[0-7]+, that is, in standard decimal, hex, or octal format.- Parameters:
pos
- INPUT-OUTPUT parameter. On input, the first character to parse. On output, the character after the last parsed character.
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parseUnicodeIdentifier
public static java.lang.String parseUnicodeIdentifier(java.lang.String str, int[] pos)
Parse a Unicode identifier from the given string at the given position. Return the identifier, or null if there is no identifier.- Parameters:
str
- the string to parsepos
- INPUT-OUTPUT parameter. On INPUT, pos[0] is the first character to examine. It must be less than str.length(), and it must not point to a whitespace character. That is, must have pos[0] < str.length(). On OUTPUT, the position after the last parsed character.- Returns:
- the Unicode identifier, or null if there is no valid identifier at pos[0].
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recursiveAppendNumber
private static <T extends java.lang.Appendable> void recursiveAppendNumber(T result, int n, int radix, int minDigits)
Append the digits of a positive integer to the givenAppendable
in the given radix. This is done recursively since it is easiest to generate the low- order digit first, but it must be appended last.- Parameters:
result
- is theAppendable
to append ton
- is the positive integerradix
- is the radix, from 2 to 36 inclusiveminDigits
- is the minimum number of digits to append.
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appendNumber
public static <T extends java.lang.Appendable> T appendNumber(T result, int n, int radix, int minDigits)
Append a number to the given Appendable in the given radix. Standard digits '0'-'9' are used and letters 'A'-'Z' for radices 11 through 36.- Parameters:
result
- the digits of the number are appended heren
- the number to be converted to digits; may be negative. If negative, a '-' is prepended to the digits.radix
- a radix from 2 to 36 inclusive.minDigits
- the minimum number of digits, not including any '-', to produce. Values less than 2 have no effect. One digit is always emitted regardless of this parameter.- Returns:
- a reference to result
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parseNumber
public static int parseNumber(java.lang.String text, int[] pos, int radix)
Parse an unsigned 31-bit integer at the given offset. Use UCharacter.digit() to parse individual characters into digits.- Parameters:
text
- the text to be parsedpos
- INPUT-OUTPUT parameter. On entry, pos[0] is the offset within text at which to start parsing; it should point to a valid digit. On exit, pos[0] is the offset after the last parsed character. If the parse failed, it will be unchanged on exit. Must be >= 0 on entry.radix
- the radix in which to parse; must be >= 2 and <= 36.- Returns:
- a non-negative parsed number, or -1 upon parse failure. Parse fails if there are no digits, that is, if pos[0] does not point to a valid digit on entry, or if the number to be parsed does not fit into a 31-bit unsigned integer.
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isUnprintable
public static boolean isUnprintable(int c)
Return true if the character is NOT printable ASCII. The tab, newline and linefeed characters are considered unprintable.
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shouldAlwaysBeEscaped
public static boolean shouldAlwaysBeEscaped(int c)
- Returns:
- true for control codes and for surrogate and noncharacter code points
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escapeUnprintable
public static <T extends java.lang.Appendable> boolean escapeUnprintable(T result, int c)
Escapes one unprintable code point usinguxxxx notation for U+0000 to U+FFFF and Uxxxxxxxx for U+10000 and above. If the character is printable ASCII, then do nothing and return false. Otherwise, append the escaped notation and return true.
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escape
public static <T extends java.lang.Appendable> T escape(T result, int c)
Escapes one code point usinguxxxx notation for U+0000 to U+FFFF and Uxxxxxxxx for U+10000 and above. - Returns:
- result
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quotedIndexOf
public static int quotedIndexOf(java.lang.String text, int start, int limit, java.lang.String setOfChars)
Returns the index of the first character in a set, ignoring quoted text. For example, in the string "abc'hide'h", the 'h' in "hide" will not be found by a search for "h". Unlike String.indexOf(), this method searches not for a single character, but for any character of the stringsetOfChars
.- Parameters:
text
- text to be searchedstart
- the beginning index, inclusive;0 <= start <= limit
.limit
- the ending index, exclusive;start <= limit <= text.length()
.setOfChars
- string with one or more distinct characters- Returns:
- Offset of the first character in
setOfChars
found, or -1 if not found. - See Also:
String.indexOf(int)
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appendToRule
public static void appendToRule(java.lang.StringBuffer rule, int c, boolean isLiteral, boolean escapeUnprintable, java.lang.StringBuffer quoteBuf)
Append a character to a rule that is being built up. To flush the quoteBuf to rule, make one final call with isLiteral == true. If there is no final character, pass in (int)-1 as c.- Parameters:
rule
- the string to append the character toc
- the character to append, or (int)-1 if none.isLiteral
- if true, then the given character should not be quoted or escaped. Usually this means it is a syntactic element such as > or $escapeUnprintable
- if true, then unprintable characters should be escaped using escapeUnprintable(). These escapes will appear outside of quotes.quoteBuf
- a buffer which is used to build up quoted substrings. The caller should initially supply an empty buffer, and thereafter should not modify the buffer. The buffer should be cleared out by, at the end, calling this method with a literal character (which may be -1).
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appendToRule
public static void appendToRule(java.lang.StringBuffer rule, java.lang.String text, boolean isLiteral, boolean escapeUnprintable, java.lang.StringBuffer quoteBuf)
Append the given string to the rule. Calls the single-character version of appendToRule for each character.
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appendToRule
public static void appendToRule(java.lang.StringBuffer rule, UnicodeMatcher matcher, boolean escapeUnprintable, java.lang.StringBuffer quoteBuf)
Given a matcher reference, which may be null, append its pattern as a literal to the given rule.
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compareUnsigned
public static final int compareUnsigned(int source, int target)
Compares 2 unsigned integers- Parameters:
source
- 32 bit unsigned integertarget
- 32 bit unsigned integer- Returns:
- 0 if equals, 1 if source is greater than target and -1 otherwise
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highBit
public static final byte highBit(int n)
Find the highest bit in a positive integer. This is done by doing a binary search through the bits.- Parameters:
n
- is the integer- Returns:
- the bit number of the highest bit, with 0 being
the low order bit, or -1 if
n
is not positive
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valueOf
public static java.lang.String valueOf(int[] source)
Utility method to take a int[] containing codepoints and return a string representation with code units.
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repeat
public static java.lang.String repeat(java.lang.String s, int count)
Utility to duplicate a string count times- Parameters:
s
- String to be duplicated.count
- Number of times to duplicate a string.
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splitString
public static java.lang.String[] splitString(java.lang.String src, java.lang.String target)
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splitWhitespace
public static java.lang.String[] splitWhitespace(java.lang.String src)
Split the string at runs of ascii whitespace characters.
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fromHex
public static java.lang.String fromHex(java.lang.String string, int minLength, java.lang.String separator)
Parse a list of hex numbers and return a string- Parameters:
string
- String of hex numbers.minLength
- Minimal length.separator
- Separator.- Returns:
- A string from hex numbers.
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fromHex
public static java.lang.String fromHex(java.lang.String string, int minLength, java.util.regex.Pattern separator)
Parse a list of hex numbers and return a string- Parameters:
string
- String of hex numbers.minLength
- Minimal length.separator
- Separator.- Returns:
- A string from hex numbers.
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addExact
public static int addExact(int x, int y)
This implementation is equivalent to Java 8+ Math#addExact(int, int)- Parameters:
x
- the first valuey
- the second value- Returns:
- the result
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charSequenceEquals
public static boolean charSequenceEquals(java.lang.CharSequence a, java.lang.CharSequence b)
Returns whether the chars in the two CharSequences are equal.
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charSequenceHashCode
public static int charSequenceHashCode(java.lang.CharSequence value)
Returns a hash code for a CharSequence that is equivalent to calling charSequence.toString().hashCode()
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appendTo
public static <A extends java.lang.Appendable> A appendTo(java.lang.CharSequence string, A appendable)
Appends a CharSequence to an Appendable, converting IOException to ICUUncheckedIOException.
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joinStrings
public static java.lang.String joinStrings(java.lang.CharSequence delimiter, java.lang.Iterable<? extends java.lang.CharSequence> elements)
Java 8+ String#join(CharSequence, Iterable extends CharSequence>) compatible method for Java 7 env.- Parameters:
delimiter
- the delimiter that separates each elementelements
- the elements to join together.- Returns:
- a new String that is composed of the elements separated by the delimiter
- Throws:
java.lang.NullPointerException
- If delimiter or elements is null
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