Class Utility

java.lang.Object
com.ibm.icu.impl.Utility

public final class Utility extends Object
  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    private static final char
     
    private static final char
     
    (package private) static final char[]
     
    private static final char
    The ESCAPE character is used during run-length encoding.
    (package private) static final byte
    The ESCAPE_BYTE character is used during run-length encoding.
    (package private) static final char[]
     
    static String
     
    private static final int
     
    private static final char[]
     
  • Constructor Summary

    Constructors
    Constructor
    Description
     
  • Method Summary

    Modifier and Type
    Method
    Description
    private static final int
    _digit16(int c)
     
    private static final int
    _digit8(int c)
     
    static int
    addExact(int x, int y)
    This implementation is equivalent to Java 8+ Math#addExact(int, int)
    private static final <T extends Appendable>
    void
    appendEncodedByte(T buffer, byte value, byte[] state)
    Append a byte to the given Appendable, packing two bytes into each character.
    private static final <T extends Appendable>
    void
    appendInt(T buffer, int value)
     
    static <T extends Appendable>
    T
    appendNumber(T result, int n, int radix, int minDigits)
    Append a number to the given Appendable in the given radix.
    static <A extends Appendable>
    A
    appendTo(CharSequence string, A appendable)
    Appends a CharSequence to an Appendable, converting IOException to ICUUncheckedIOException.
    static void
    appendToRule(StringBuffer rule, int c, boolean isLiteral, boolean escapeUnprintable, StringBuffer quoteBuf)
    Append a character to a rule that is being built up.
    static void
    appendToRule(StringBuffer rule, UnicodeMatcher matcher, boolean escapeUnprintable, StringBuffer quoteBuf)
    Given a matcher reference, which may be null, append its pattern as a literal to the given rule.
    static void
    appendToRule(StringBuffer rule, String text, boolean isLiteral, boolean escapeUnprintable, StringBuffer quoteBuf)
    Append the given string to the rule.
    static final boolean
    arrayEquals(byte[] source, Object target)
     
    static final boolean
    arrayEquals(double[] source, Object target)
    Convenience utility to compare two double[]s Ought to be in System
    static final boolean
    arrayEquals(int[] source, Object target)
    Convenience utility to compare two int[]s Ought to be in System
    static final boolean
    arrayEquals(Object[] source, Object target)
    Convenience utility to compare two Object[]s.
    static final boolean
    arrayEquals(Object source, Object target)
    Convenience utility to compare two Object[]s Ought to be in System
    static final boolean
    arrayRegionMatches(byte[] source, int sourceStart, byte[] target, int targetStart, int len)
     
    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.
    static final boolean
    arrayRegionMatches(double[] source, int sourceStart, double[] target, int targetStart, int len)
    Convenience utility to compare two arrays of doubles.
    static final boolean
    arrayRegionMatches(int[] source, int sourceStart, int[] target, int targetStart, int len)
    Convenience utility to compare two int[]s.
    static final boolean
    arrayRegionMatches(Object[] source, int sourceStart, Object[] target, int targetStart, int len)
    Convenience utility to compare two Object[]s Ought to be in System.
    static final String
    arrayToRLEString(byte[] a)
    Construct a string representing a byte array.
    static final String
    arrayToRLEString(char[] a)
    Construct a string representing a char array.
    static final String
    Construct a string representing an int array.
    static final String
    arrayToRLEString(short[] a)
    Construct a string representing a short array.
    static boolean
    Returns whether the chars in the two CharSequences are equal.
    static int
    Returns a hash code for a CharSequence that is equivalent to calling charSequence.toString().hashCode()
    static <T extends Comparable<T>>
    int
    checkCompare(T a, T b)
    Convenience utility.
    static int
    Convenience utility.
    private static int
    codePointAndLength(int c, int length)
     
    private static int
    codePointAndLength(int c, int start, int limit)
     
    static final int
    compareUnsigned(int source, int target)
    Compares 2 unsigned integers
    static int
    cpFromCodePointAndLength(int cpAndLength)
     
    private static final <T extends Appendable>
    void
    encodeRun(T buffer, byte value, int length, byte[] state)
    Encode a run, possibly a degenerate run (of < 4 values).
    private static final <T extends Appendable>
    void
    encodeRun(T buffer, int value, int length)
    Encode a run, possibly a degenerate run (of < 4 values).
    private static final <T extends Appendable>
    void
    encodeRun(T buffer, short value, int length)
    Encode a run, possibly a degenerate run (of < 4 values).
    static final String
    Convert characters outside the range U+0020 to U+007F to Unicode escapes, and convert backslash to a double backslash.
    static <T extends Appendable>
    T
    escape(T result, int c)
    Escapes one code point using uxxxx notation for U+0000 to U+FFFF and Uxxxxxxxx for U+10000 and above.
    static <T extends Appendable>
    boolean
    escapeUnprintable(T result, int c)
    Escapes one unprintable code point using uxxxx notation for U+0000 to U+FFFF and Uxxxxxxxx for U+10000 and above.
    static final String
    Format a String for representation in a source file.
    static final String
    Format a String for representation in a source file.
    static String
    fromHex(String string, int minLength, String separator)
    Parse a list of hex numbers and return a string
    static String
    fromHex(String string, int minLength, Pattern separator)
    Parse a list of hex numbers and return a string
    (package private) static final int
    getInt(String s, int i)
     
    static String
    hex(byte[] o, int start, int end, String separator)
     
    static String
    hex(long ch)
    Convert a char to 4 hex uppercase digits.
    static String
    hex(long i, int places)
    Supplies a zero-padded hex representation of an integer (without 0x)
    static String
    Convert a string to comma-separated groups of 4 hex uppercase digits.
    static <S extends CharSequence>
    String
    hex(S s, int width, S separator)
    Convert a string to comma-separated groups of 4 hex uppercase digits.
    static <S extends CharSequence, U extends CharSequence, T extends Appendable>
    T
    hex(S s, int width, U separator, boolean useCodePoints, T result)
    Convert a string to separated groups of hex uppercase digits.
    static final byte
    highBit(int n)
    Find the highest bit in a positive integer.
    static boolean
    Return true if the character is NOT printable ASCII.
    static String
    joinStrings(CharSequence delimiter, Iterable<? extends CharSequence> elements)
    Java 8+ String#join(CharSequence, Iterable<? extends CharSequence>) compatible method for Java 7 env.
    static int
     
    static int
    lookup(String source, String[] target)
    Look up a given string in a string array.
    static boolean
    parseChar(String id, int[] pos, char ch)
    Parse a single non-whitespace character 'ch', optionally preceded by whitespace.
    static int
    parseInteger(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(String text, int[] pos, int radix)
    Parse an unsigned 31-bit integer at the given offset.
    static int
    parsePattern(String rule, int pos, int limit, String pattern, int[] parsedInts)
    Parse a pattern string starting at offset pos.
    static int
    parsePattern(String pat, Replaceable text, int index, int limit)
    Parse a pattern string within the given Replaceable and a parsing pattern.
    static String
    parseUnicodeIdentifier(String str, int[] pos)
    Parse a Unicode identifier from the given string at the given position.
    static int
    quotedIndexOf(String text, int start, int limit, String setOfChars)
    Returns the index of the first character in a set, ignoring quoted text.
    private static <T extends Appendable>
    void
    recursiveAppendNumber(T result, int n, int radix, int minDigits)
    Append the digits of a positive integer to the given Appendable in the given radix.
    static String
    repeat(String s, int count)
    Utility to duplicate a string count times
    static final byte[]
    Construct an array of bytes from a run-length encoded string.
    static final char[]
    Construct an array of shorts from a run-length encoded string.
    static final int[]
    Construct an array of ints from a run-length encoded string.
    static final short[]
    Construct an array of shorts from a run-length encoded string.
    static final boolean
    Trivial reference equality.
    static boolean
     
    static String[]
    split(String s, char divider)
    Split a string into pieces based on the given divider character
    static void
    split(String s, char divider, String[] output)
    Split a string into pieces based on the given divider character
    static String[]
    splitString(String src, String target)
     
    static String[]
    Split the string at runs of ascii whitespace characters.
    static String
    Convert all escapes in a given string using unescapeAndLengthAt().
    static int
    Converts an escape to a code point value.
    private static int
    unescapeAndLengthAt(CharSequence s, int offset, int length)
     
    static String
    Convert all escapes in a given string using unescapeAndLengthAt().
    static String
    valueOf(int[] source)
    Utility method to take a int[] containing codepoints and return a string representation with code units.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
  • Field Details

    • APOSTROPHE

      private static final char APOSTROPHE
      See Also:
    • BACKSLASH

      private static final char BACKSLASH
      See Also:
    • MAGIC_UNSIGNED

      private static final int MAGIC_UNSIGNED
      See Also:
    • ESCAPE

      private static final char ESCAPE
      The ESCAPE character is used during run-length encoding. It signals a run of identical chars.
      See Also:
    • 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:
    • LINE_SEPARATOR

      public static String LINE_SEPARATOR
    • HEX_DIGIT

      static final char[] HEX_DIGIT
    • UNESCAPE_MAP

      private static final char[] UNESCAPE_MAP
    • DIGITS

      static final char[] DIGITS
  • Constructor Details

    • Utility

      public Utility()
  • Method Details

    • arrayEquals

      public static final boolean arrayEquals(Object[] source, Object target)
      Convenience utility to compare two Object[]s. Ought to be in System
    • arrayEquals

      public static final boolean arrayEquals(int[] source, Object target)
      Convenience utility to compare two int[]s Ought to be in System
    • arrayEquals

      public static final boolean arrayEquals(double[] source, Object target)
      Convenience utility to compare two double[]s Ought to be in System
    • arrayEquals

      public static final boolean arrayEquals(byte[] source, Object target)
    • arrayEquals

      public static final boolean arrayEquals(Object source, Object target)
      Convenience utility to compare two Object[]s Ought to be in System
    • arrayRegionMatches

      public static final boolean arrayRegionMatches(Object[] source, int sourceStart, 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.
    • 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.
    • 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
    • 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
    • arrayRegionMatches

      public static final boolean arrayRegionMatches(byte[] source, int sourceStart, byte[] target, int targetStart, int len)
    • sameObjects

      public static final boolean sameObjects(Object a, 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.
    • checkCompare

      public static <T extends Comparable<T>> int checkCompare(T a, T b)
      Convenience utility. Does null checks on objects, then calls compare.
    • checkHash

      public static int checkHash(Object a)
      Convenience utility. Does null checks on object, then calls hashCode.
    • arrayToRLEString

      public static final 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.
    • arrayToRLEString

      public static final 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.
    • arrayToRLEString

      public static final 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.
    • arrayToRLEString

      public static final 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.
    • encodeRun

      private static final <T extends 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.
    • appendInt

      private static final <T extends Appendable> void appendInt(T buffer, int value)
    • encodeRun

      private static final <T extends 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.
    • encodeRun

      private static final <T extends 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.
    • appendEncodedByte

      private static final <T extends 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.
    • RLEStringToIntArray

      public static final int[] RLEStringToIntArray(String s)
      Construct an array of ints from a run-length encoded string.
    • getInt

      static final int getInt(String s, int i)
    • RLEStringToShortArray

      public static final short[] RLEStringToShortArray(String s)
      Construct an array of shorts from a run-length encoded string.
    • RLEStringToCharArray

      public static final char[] RLEStringToCharArray(String s)
      Construct an array of shorts from a run-length encoded string.
    • RLEStringToByteArray

      public static final byte[] RLEStringToByteArray(String s)
      Construct an array of bytes from a run-length encoded string.
    • formatForSource

      public static final String formatForSource(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).
    • format1ForSource

      public static final String format1ForSource(String s)
      Format a String for representation in a source file. Like formatForSource but does not do line breaking.
    • escape

      public static final String escape(String s)
      Convert characters outside the range U+0020 to U+007F to Unicode escapes, and convert backslash to a double backslash.
    • _digit8

      private static final int _digit8(int c)
    • _digit16

      private static final int _digit16(int c)
    • unescapeAndLengthAt

      public static int unescapeAndLengthAt(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.
    • unescapeAndLengthAt

      private static int unescapeAndLengthAt(CharSequence s, int offset, int length)
    • codePointAndLength

      private static int codePointAndLength(int c, int length)
    • codePointAndLength

      private static int codePointAndLength(int c, int start, int limit)
    • cpFromCodePointAndLength

      public static int cpFromCodePointAndLength(int cpAndLength)
    • lengthFromCodePointAndLength

      public static int lengthFromCodePointAndLength(int cpAndLength)
    • unescape

      public static String unescape(CharSequence s)
      Convert all escapes in a given string using unescapeAndLengthAt().
      Throws:
      IllegalArgumentException - if an invalid escape is seen.
    • unescapeLeniently

      public static String unescapeLeniently(CharSequence s)
      Convert all escapes in a given string using unescapeAndLengthAt(). Leave invalid escape sequences unchanged.
    • hex

      public static String hex(long ch)
      Convert a char to 4 hex uppercase digits. E.g., hex('a') => "0041".
    • hex

      public static String hex(long i, int places)
      Supplies a zero-padded hex representation of an integer (without 0x)
    • hex

      public static String hex(CharSequence s)
      Convert a string to comma-separated groups of 4 hex uppercase digits. E.g., hex('ab') => "0041,0042".
    • hex

      public static <S extends CharSequence, U extends CharSequence, T extends 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.
    • hex

      public static String hex(byte[] o, int start, int end, String separator)
    • hex

      public static <S extends CharSequence> 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".
    • split

      public static void split(String s, char divider, String[] output)
      Split a string into pieces based on the given divider character
      Parameters:
      s - the string to split
      divider - the character on which to split. Occurrences of this character are not included in the output
      output - 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.
    • split

      public static String[] split(String s, char divider)
      Split a string into pieces based on the given divider character
      Parameters:
      s - the string to split
      divider - 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.
    • lookup

      public static int lookup(String source, 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 for
      target - 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
    • parseChar

      public static boolean parseChar(String id, int[] pos, char ch)
      Parse a single non-whitespace character 'ch', optionally preceded by whitespace.
      Parameters:
      id - the string to be parsed
      pos - 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.
    • parsePattern

      public static int parsePattern(String rule, int pos, int limit, 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
    • parsePattern

      public static int parsePattern(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 parsing
      text - text to be parsed, starting at index
      index - offset to first character to parse
      limit - offset after last character to parse
      Returns:
      index after last parsed character, or -1 on parse failure.
    • parseInteger

      public static int parseInteger(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.
    • parseUnicodeIdentifier

      public static String parseUnicodeIdentifier(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 parse
      pos - 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].
    • recursiveAppendNumber

      private static <T extends Appendable> void recursiveAppendNumber(T result, int n, int radix, int minDigits)
      Append the digits of a positive integer to the given Appendable 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 the Appendable to append to
      n - is the positive integer
      radix - is the radix, from 2 to 36 inclusive
      minDigits - is the minimum number of digits to append.
    • appendNumber

      public static <T extends 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 here
      n - 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
    • parseNumber

      public static int parseNumber(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 parsed
      pos - 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.
    • 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.
    • shouldAlwaysBeEscaped

      public static boolean shouldAlwaysBeEscaped(int c)
      Returns:
      true for control codes and for surrogate and noncharacter code points
    • escapeUnprintable

      public static <T extends Appendable> boolean escapeUnprintable(T result, int c)
      Escapes one unprintable code point using uxxxx 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.
    • escape

      public static <T extends Appendable> T escape(T result, int c)
      Escapes one code point using uxxxx notation for U+0000 to U+FFFF and Uxxxxxxxx for U+10000 and above.
      Returns:
      result
    • quotedIndexOf

      public static int quotedIndexOf(String text, int start, int limit, 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 string setOfChars.
      Parameters:
      text - text to be searched
      start - 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:
    • appendToRule

      public static void appendToRule(StringBuffer rule, int c, boolean isLiteral, boolean escapeUnprintable, 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 to
      c - 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).
    • appendToRule

      public static void appendToRule(StringBuffer rule, String text, boolean isLiteral, boolean escapeUnprintable, StringBuffer quoteBuf)
      Append the given string to the rule. Calls the single-character version of appendToRule for each character.
    • appendToRule

      public static void appendToRule(StringBuffer rule, UnicodeMatcher matcher, boolean escapeUnprintable, StringBuffer quoteBuf)
      Given a matcher reference, which may be null, append its pattern as a literal to the given rule.
    • compareUnsigned

      public static final int compareUnsigned(int source, int target)
      Compares 2 unsigned integers
      Parameters:
      source - 32 bit unsigned integer
      target - 32 bit unsigned integer
      Returns:
      0 if equals, 1 if source is greater than target and -1 otherwise
    • 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
    • valueOf

      public static String valueOf(int[] source)
      Utility method to take a int[] containing codepoints and return a string representation with code units.
    • repeat

      public static String repeat(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.
    • splitString

      public static String[] splitString(String src, String target)
    • splitWhitespace

      public static String[] splitWhitespace(String src)
      Split the string at runs of ascii whitespace characters.
    • fromHex

      public static String fromHex(String string, int minLength, 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.
    • fromHex

      public static String fromHex(String string, int minLength, 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.
    • addExact

      public static int addExact(int x, int y)
      This implementation is equivalent to Java 8+ Math#addExact(int, int)
      Parameters:
      x - the first value
      y - the second value
      Returns:
      the result
    • charSequenceEquals

      public static boolean charSequenceEquals(CharSequence a, CharSequence b)
      Returns whether the chars in the two CharSequences are equal.
    • charSequenceHashCode

      public static int charSequenceHashCode(CharSequence value)
      Returns a hash code for a CharSequence that is equivalent to calling charSequence.toString().hashCode()
    • appendTo

      public static <A extends Appendable> A appendTo(CharSequence string, A appendable)
      Appends a CharSequence to an Appendable, converting IOException to ICUUncheckedIOException.
    • joinStrings

      public static String joinStrings(CharSequence delimiter, Iterable<? extends CharSequence> elements)
      Java 8+ String#join(CharSequence, Iterable<? extends CharSequence>) compatible method for Java 7 env.
      Parameters:
      delimiter - the delimiter that separates each element
      elements - the elements to join together.
      Returns:
      a new String that is composed of the elements separated by the delimiter
      Throws:
      NullPointerException - If delimiter or elements is null