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// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/**
*******************************************************************************
* Copyright (C) 1996-2016, International Business Machines Corporation and
* others. All Rights Reserved.
*******************************************************************************
*/
package com.ibm.icu.text;
import com.ibm.icu.impl.Utility;
/**
*
* Standalone utility class providing UTF16 character conversions and indexing conversions.
*
*
* Code that uses strings alone rarely need modification. By design, UTF-16 does not allow overlap,
* so searching for strings is a safe operation. Similarly, concatenation is always safe.
* Substringing is safe if the start and end are both on UTF-32 boundaries. In normal code, the
* values for start and end are on those boundaries, since they arose from operations like
* searching. If not, the nearest UTF-32 boundaries can be determined using bounds().
*
* Examples:
*
* The following examples illustrate use of some of these methods.
*
*
* // iteration forwards: Original
* for (int i = 0; i < s.length(); ++i) {
* char ch = s.charAt(i);
* doSomethingWith(ch);
* }
*
* // iteration forwards: Changes for UTF-32
* int ch;
* for (int i = 0; i < s.length(); i += UTF16.getCharCount(ch)) {
* ch = UTF16.charAt(s, i);
* doSomethingWith(ch);
* }
*
* // iteration backwards: Original
* for (int i = s.length() - 1; i >= 0; --i) {
* char ch = s.charAt(i);
* doSomethingWith(ch);
* }
*
* // iteration backwards: Changes for UTF-32
* int ch;
* for (int i = s.length() - 1; i > 0; i -= UTF16.getCharCount(ch)) {
* ch = UTF16.charAt(s, i);
* doSomethingWith(ch);
* }
*
*
* Notes:
*
* - Naming: For clarity, High and Low surrogates are called
Lead
* and Trail in the API, which gives a better sense of their ordering in a string.
* offset16 and offset32 are used to distinguish offsets to UTF-16
* boundaries vs offsets to UTF-32 boundaries. int char32 is used to contain UTF-32
* characters, as opposed to char16, which is a UTF-16 code unit.
* - Roundtripping Offsets: You can always roundtrip from a UTF-32 offset to a
* UTF-16 offset and back. Because of the difference in structure, you can roundtrip from a UTF-16
* offset to a UTF-32 offset and back if and only if
bounds(string, offset16) != TRAIL.
*
* - Exceptions: The error checking will throw an exception if indices are out
* of bounds. Other than than that, all methods will behave reasonably, even if unmatched surrogates
* or out-of-bounds UTF-32 values are present.
UCharacter.isLegal() can be used to
* check for validity if desired.
* - Unmatched Surrogates: If the string contains unmatched surrogates, then
* these are counted as one UTF-32 value. This matches their iteration behavior, which is vital. It
* also matches common display practice as missing glyphs (see the Unicode Standard Section 5.4,
* 5.5).
* - Optimization: The method implementations may need optimization if the
* compiler doesn't fold static final methods. Since surrogate pairs will form an exceeding small
* percentage of all the text in the world, the singleton case should always be optimized for.
*
*
* @author Mark Davis, with help from Markus Scherer
* @stable ICU 2.1
*/
public final class UTF16 {
// public variables ---------------------------------------------------
/**
* Value returned in {@link #bounds(String, int) bounds()}.
* These values are chosen specifically so that it actually represents the position of the
* character [offset16 - (value >> 2), offset16 + (value & 3)]
*
* @stable ICU 2.1
*/
public static final int SINGLE_CHAR_BOUNDARY = 1, LEAD_SURROGATE_BOUNDARY = 2,
TRAIL_SURROGATE_BOUNDARY = 5;
/**
* The lowest Unicode code point value.
*
* @stable ICU 2.1
*/
public static final int CODEPOINT_MIN_VALUE = 0;
/**
* The highest Unicode code point value (scalar value) according to the Unicode Standard.
*
* @stable ICU 2.1
*/
public static final int CODEPOINT_MAX_VALUE = 0x10ffff;
/**
* The minimum value for Supplementary code points
*
* @stable ICU 2.1
*/
public static final int SUPPLEMENTARY_MIN_VALUE = 0x10000;
/**
* Lead surrogate minimum value
*
* @stable ICU 2.1
*/
public static final int LEAD_SURROGATE_MIN_VALUE = 0xD800;
/**
* Trail surrogate minimum value
*
* @stable ICU 2.1
*/
public static final int TRAIL_SURROGATE_MIN_VALUE = 0xDC00;
/**
* Lead surrogate maximum value
*
* @stable ICU 2.1
*/
public static final int LEAD_SURROGATE_MAX_VALUE = 0xDBFF;
/**
* Trail surrogate maximum value
*
* @stable ICU 2.1
*/
public static final int TRAIL_SURROGATE_MAX_VALUE = 0xDFFF;
/**
* Surrogate minimum value
*
* @stable ICU 2.1
*/
public static final int SURROGATE_MIN_VALUE = LEAD_SURROGATE_MIN_VALUE;
/**
* Maximum surrogate value
*
* @stable ICU 2.1
*/
public static final int SURROGATE_MAX_VALUE = TRAIL_SURROGATE_MAX_VALUE;
/**
* Lead surrogate bitmask
*/
private static final int LEAD_SURROGATE_BITMASK = 0xFFFFFC00;
/**
* Trail surrogate bitmask
*/
private static final int TRAIL_SURROGATE_BITMASK = 0xFFFFFC00;
/**
* Surrogate bitmask
*/
private static final int SURROGATE_BITMASK = 0xFFFFF800;
/**
* Lead surrogate bits
*/
private static final int LEAD_SURROGATE_BITS = 0xD800;
/**
* Trail surrogate bits
*/
private static final int TRAIL_SURROGATE_BITS = 0xDC00;
/**
* Surrogate bits
*/
private static final int SURROGATE_BITS = 0xD800;
// constructor --------------------------------------------------------
// /CLOVER:OFF
/**
* Prevent instance from being created.
*/
private UTF16() {
}
// /CLOVER:ON
// public method ------------------------------------------------------
/**
* Extract a single UTF-32 value from a string. Used when iterating forwards or backwards (with
* UTF16.getCharCount(), as well as random access. If a validity check is
* required, use
* UCharacter.isLegal()
* on the return value. If the char retrieved is part of a surrogate pair, its supplementary
* character will be returned. If a complete supplementary character is not found the incomplete
* character will be returned
*
* @param source Array of UTF-16 chars
* @param offset16 UTF-16 offset to the start of the character.
* @return UTF-32 value for the UTF-32 value that contains the char at offset16. The boundaries
* of that codepoint are the same as in bounds32().
* @exception IndexOutOfBoundsException Thrown if offset16 is out of bounds.
* @stable ICU 2.1
*/
public static int charAt(String source, int offset16) {
char single = source.charAt(offset16);
if (single < LEAD_SURROGATE_MIN_VALUE) {
return single;
}
return _charAt(source, offset16, single);
}
private static int _charAt(String source, int offset16, char single) {
if (single > TRAIL_SURROGATE_MAX_VALUE) {
return single;
}
// Convert the UTF-16 surrogate pair if necessary.
// For simplicity in usage, and because the frequency of pairs is
// low, look both directions.
if (single <= LEAD_SURROGATE_MAX_VALUE) {
++offset16;
if (source.length() != offset16) {
char trail = source.charAt(offset16);
if (trail >= TRAIL_SURROGATE_MIN_VALUE && trail <= TRAIL_SURROGATE_MAX_VALUE) {
return Character.toCodePoint(single, trail);
}
}
} else {
--offset16;
if (offset16 >= 0) {
// single is a trail surrogate so
char lead = source.charAt(offset16);
if (lead >= LEAD_SURROGATE_MIN_VALUE && lead <= LEAD_SURROGATE_MAX_VALUE) {
return Character.toCodePoint(lead, single);
}
}
}
return single; // return unmatched surrogate
}
/**
* Extract a single UTF-32 value from a string. Used when iterating forwards or backwards (with
* UTF16.getCharCount(), as well as random access. If a validity check is
* required, use
* UCharacter.isLegal()
* on the return value. If the char retrieved is part of a surrogate pair, its supplementary
* character will be returned. If a complete supplementary character is not found the incomplete
* character will be returned
*
* @param source Array of UTF-16 chars
* @param offset16 UTF-16 offset to the start of the character.
* @return UTF-32 value for the UTF-32 value that contains the char at offset16. The boundaries
* of that codepoint are the same as in bounds32().
* @exception IndexOutOfBoundsException Thrown if offset16 is out of bounds.
* @stable ICU 2.1
*/
public static int charAt(CharSequence source, int offset16) {
char single = source.charAt(offset16);
if (single < UTF16.LEAD_SURROGATE_MIN_VALUE) {
return single;
}
return _charAt(source, offset16, single);
}
private static int _charAt(CharSequence source, int offset16, char single) {
if (single > UTF16.TRAIL_SURROGATE_MAX_VALUE) {
return single;
}
// Convert the UTF-16 surrogate pair if necessary.
// For simplicity in usage, and because the frequency of pairs is
// low, look both directions.
if (single <= UTF16.LEAD_SURROGATE_MAX_VALUE) {
++offset16;
if (source.length() != offset16) {
char trail = source.charAt(offset16);
if (trail >= UTF16.TRAIL_SURROGATE_MIN_VALUE
&& trail <= UTF16.TRAIL_SURROGATE_MAX_VALUE) {
return Character.toCodePoint(single, trail);
}
}
} else {
--offset16;
if (offset16 >= 0) {
// single is a trail surrogate so
char lead = source.charAt(offset16);
if (lead >= UTF16.LEAD_SURROGATE_MIN_VALUE
&& lead <= UTF16.LEAD_SURROGATE_MAX_VALUE) {
return Character.toCodePoint(lead, single);
}
}
}
return single; // return unmatched surrogate
}
/**
* Extract a single UTF-32 value from a string. Used when iterating forwards or backwards (with
* UTF16.getCharCount(), as well as random access. If a validity check is
* required, use UCharacter.isLegal()
*
* on the return value. If the char retrieved is part of a surrogate pair, its supplementary
* character will be returned. If a complete supplementary character is not found the incomplete
* character will be returned
*
* @param source UTF-16 chars string buffer
* @param offset16 UTF-16 offset to the start of the character.
* @return UTF-32 value for the UTF-32 value that contains the char at offset16. The boundaries
* of that codepoint are the same as in bounds32().
* @exception IndexOutOfBoundsException Thrown if offset16 is out of bounds.
* @stable ICU 2.1
*/
public static int charAt(StringBuffer source, int offset16) {
if (offset16 < 0 || offset16 >= source.length()) {
throw new StringIndexOutOfBoundsException(offset16);
}
char single = source.charAt(offset16);
if (!isSurrogate(single)) {
return single;
}
// Convert the UTF-16 surrogate pair if necessary.
// For simplicity in usage, and because the frequency of pairs is
// low, look both directions.
if (single <= LEAD_SURROGATE_MAX_VALUE) {
++offset16;
if (source.length() != offset16) {
char trail = source.charAt(offset16);
if (isTrailSurrogate(trail))
return Character.toCodePoint(single, trail);
}
} else {
--offset16;
if (offset16 >= 0) {
// single is a trail surrogate so
char lead = source.charAt(offset16);
if (isLeadSurrogate(lead)) {
return Character.toCodePoint(lead, single);
}
}
}
return single; // return unmatched surrogate
}
/**
* Extract a single UTF-32 value from a substring. Used when iterating forwards or backwards
* (with UTF16.getCharCount(), as well as random access. If a validity check is
* required, use UCharacter.isLegal()
*
* on the return value. If the char retrieved is part of a surrogate pair, its supplementary
* character will be returned. If a complete supplementary character is not found the incomplete
* character will be returned
*
* @param source Array of UTF-16 chars
* @param start Offset to substring in the source array for analyzing
* @param limit Offset to substring in the source array for analyzing
* @param offset16 UTF-16 offset relative to start
* @return UTF-32 value for the UTF-32 value that contains the char at offset16. The boundaries
* of that codepoint are the same as in bounds32().
* @exception IndexOutOfBoundsException Thrown if offset16 is not within the range of start and limit.
* @stable ICU 2.1
*/
public static int charAt(char source[], int start, int limit, int offset16) {
offset16 += start;
if (offset16 < start || offset16 >= limit) {
throw new ArrayIndexOutOfBoundsException(offset16);
}
char single = source[offset16];
if (!isSurrogate(single)) {
return single;
}
// Convert the UTF-16 surrogate pair if necessary.
// For simplicity in usage, and because the frequency of pairs is
// low, look both directions.
if (single <= LEAD_SURROGATE_MAX_VALUE) {
offset16++;
if (offset16 >= limit) {
return single;
}
char trail = source[offset16];
if (isTrailSurrogate(trail)) {
return Character.toCodePoint(single, trail);
}
} else { // isTrailSurrogate(single), so
if (offset16 == start) {
return single;
}
offset16--;
char lead = source[offset16];
if (isLeadSurrogate(lead))
return Character.toCodePoint(lead, single);
}
return single; // return unmatched surrogate
}
/**
* Extract a single UTF-32 value from a string. Used when iterating forwards or backwards (with
* UTF16.getCharCount(), as well as random access. If a validity check is
* required, use UCharacter.isLegal()
*
* on the return value. If the char retrieved is part of a surrogate pair, its supplementary
* character will be returned. If a complete supplementary character is not found the incomplete
* character will be returned
*
* @param source UTF-16 chars string buffer
* @param offset16 UTF-16 offset to the start of the character.
* @return UTF-32 value for the UTF-32 value that contains the char at offset16. The boundaries
* of that codepoint are the same as in bounds32().
* @exception IndexOutOfBoundsException Thrown if offset16 is out of bounds.
* @stable ICU 2.1
*/
public static int charAt(Replaceable source, int offset16) {
if (offset16 < 0 || offset16 >= source.length()) {
throw new StringIndexOutOfBoundsException(offset16);
}
char single = source.charAt(offset16);
if (!isSurrogate(single)) {
return single;
}
// Convert the UTF-16 surrogate pair if necessary.
// For simplicity in usage, and because the frequency of pairs is
// low, look both directions.
if (single <= LEAD_SURROGATE_MAX_VALUE) {
++offset16;
if (source.length() != offset16) {
char trail = source.charAt(offset16);
if (isTrailSurrogate(trail))
return Character.toCodePoint(single, trail);
}
} else {
--offset16;
if (offset16 >= 0) {
// single is a trail surrogate so
char lead = source.charAt(offset16);
if (isLeadSurrogate(lead)) {
return Character.toCodePoint(lead, single);
}
}
}
return single; // return unmatched surrogate
}
/**
* Determines how many chars this char32 requires. If a validity check is required, use
* isLegal()
* on char32 before calling.
*
* @param char32 The input codepoint.
* @return 2 if is in supplementary space, otherwise 1.
* @stable ICU 2.1
*/
public static int getCharCount(int char32) {
if (char32 < SUPPLEMENTARY_MIN_VALUE) {
return 1;
}
return 2;
}
/**
* Returns the type of the boundaries around the char at offset16. Used for random access.
*
* @param source Text to analyse
* @param offset16 UTF-16 offset
* @return
*
* - SINGLE_CHAR_BOUNDARY : a single char; the bounds are [offset16, offset16+1]
*
- LEAD_SURROGATE_BOUNDARY : a surrogate pair starting at offset16; the bounds
* are [offset16, offset16 + 2]
*
- TRAIL_SURROGATE_BOUNDARY : a surrogate pair starting at offset16 - 1; the
* bounds are [offset16 - 1, offset16 + 1]
*
* For bit-twiddlers, the return values for these are chosen so that the boundaries
* can be gotten by: [offset16 - (value >> 2), offset16 + (value & 3)].
* @exception IndexOutOfBoundsException If offset16 is out of bounds.
* @stable ICU 2.1
*/
public static int bounds(String source, int offset16) {
char ch = source.charAt(offset16);
if (isSurrogate(ch)) {
if (isLeadSurrogate(ch)) {
if (++offset16 < source.length() && isTrailSurrogate(source.charAt(offset16))) {
return LEAD_SURROGATE_BOUNDARY;
}
} else {
// isTrailSurrogate(ch), so
--offset16;
if (offset16 >= 0 && isLeadSurrogate(source.charAt(offset16))) {
return TRAIL_SURROGATE_BOUNDARY;
}
}
}
return SINGLE_CHAR_BOUNDARY;
}
/**
* Returns the type of the boundaries around the char at offset16. Used for random access.
*
* @param source String buffer to analyse
* @param offset16 UTF16 offset
* @return
*
* - SINGLE_CHAR_BOUNDARY : a single char; the bounds are [offset16, offset16 + 1]
*
- LEAD_SURROGATE_BOUNDARY : a surrogate pair starting at offset16; the bounds
* are [offset16, offset16 + 2]
*
- TRAIL_SURROGATE_BOUNDARY : a surrogate pair starting at offset16 - 1; the
* bounds are [offset16 - 1, offset16 + 1]
*
* For bit-twiddlers, the return values for these are chosen so that the boundaries
* can be gotten by: [offset16 - (value >> 2), offset16 + (value & 3)].
* @exception IndexOutOfBoundsException If offset16 is out of bounds.
* @stable ICU 2.1
*/
public static int bounds(StringBuffer source, int offset16) {
char ch = source.charAt(offset16);
if (isSurrogate(ch)) {
if (isLeadSurrogate(ch)) {
if (++offset16 < source.length() && isTrailSurrogate(source.charAt(offset16))) {
return LEAD_SURROGATE_BOUNDARY;
}
} else {
// isTrailSurrogate(ch), so
--offset16;
if (offset16 >= 0 && isLeadSurrogate(source.charAt(offset16))) {
return TRAIL_SURROGATE_BOUNDARY;
}
}
}
return SINGLE_CHAR_BOUNDARY;
}
/**
* Returns the type of the boundaries around the char at offset16. Used for random access. Note
* that the boundaries are determined with respect to the subarray, hence the char array
* {0xD800, 0xDC00} has the result SINGLE_CHAR_BOUNDARY for start = offset16 = 0 and limit = 1.
*
* @param source Char array to analyse
* @param start Offset to substring in the source array for analyzing
* @param limit Offset to substring in the source array for analyzing
* @param offset16 UTF16 offset relative to start
* @return
*
* - SINGLE_CHAR_BOUNDARY : a single char; the bounds are
*
- LEAD_SURROGATE_BOUNDARY : a surrogate pair starting at offset16; the bounds
* are [offset16, offset16 + 2]
*
- TRAIL_SURROGATE_BOUNDARY : a surrogate pair starting at offset16 - 1; the
* bounds are [offset16 - 1, offset16 + 1]
*
* For bit-twiddlers, the boundary values for these are chosen so that the boundaries
* can be gotten by: [offset16 - (boundvalue >> 2), offset16 + (boundvalue & 3)].
* @exception IndexOutOfBoundsException If offset16 is not within the range of start and limit.
* @stable ICU 2.1
*/
public static int bounds(char source[], int start, int limit, int offset16) {
offset16 += start;
if (offset16 < start || offset16 >= limit) {
throw new ArrayIndexOutOfBoundsException(offset16);
}
char ch = source[offset16];
if (isSurrogate(ch)) {
if (isLeadSurrogate(ch)) {
++offset16;
if (offset16 < limit && isTrailSurrogate(source[offset16])) {
return LEAD_SURROGATE_BOUNDARY;
}
} else { // isTrailSurrogate(ch), so
--offset16;
if (offset16 >= start && isLeadSurrogate(source[offset16])) {
return TRAIL_SURROGATE_BOUNDARY;
}
}
}
return SINGLE_CHAR_BOUNDARY;
}
/**
* Determines whether the code point is a surrogate.
*
* @param codePoint The input character.
* (In ICU 2.1-69 the type of this parameter was char.)
* @return true If the input code point is a surrogate.
* @stable ICU 70
*/
public static boolean isSurrogate(int codePoint) {
return (codePoint & SURROGATE_BITMASK) == SURROGATE_BITS;
}
/**
* Determines whether the code point is a trail surrogate.
*
* @param codePoint The input character.
* (In ICU 2.1-69 the type of this parameter was char.)
* @return true If the input code point is a trail surrogate.
* @stable ICU 70
*/
public static boolean isTrailSurrogate(int codePoint) {
return (codePoint & TRAIL_SURROGATE_BITMASK) == TRAIL_SURROGATE_BITS;
}
/**
* Determines whether the code point is a lead surrogate.
*
* @param codePoint The input character.
* (In ICU 2.1-69 the type of this parameter was char.)
* @return true If the input code point is a lead surrogate
* @stable ICU 70
*/
public static boolean isLeadSurrogate(int codePoint) {
return (codePoint & LEAD_SURROGATE_BITMASK) == LEAD_SURROGATE_BITS;
}
/**
* Returns the lead surrogate. If a validity check is required, use
* isLegal() on char32
* before calling.
*
* @param char32 The input character.
* @return lead surrogate if the getCharCount(ch) is 2;
* and 0 otherwise (note: 0 is not a valid lead surrogate).
* @stable ICU 2.1
*/
public static char getLeadSurrogate(int char32) {
if (char32 >= SUPPLEMENTARY_MIN_VALUE) {
return (char) (LEAD_SURROGATE_OFFSET_ + (char32 >> LEAD_SURROGATE_SHIFT_));
}
return 0;
}
/**
* Returns the trail surrogate. If a validity check is required, use
* isLegal() on char32
* before calling.
*
* @param char32 The input character.
* @return the trail surrogate if the getCharCount(ch) is 2;
* otherwise the character itself
* @stable ICU 2.1
*/
public static char getTrailSurrogate(int char32) {
if (char32 >= SUPPLEMENTARY_MIN_VALUE) {
return (char) (TRAIL_SURROGATE_MIN_VALUE + (char32 & TRAIL_SURROGATE_MASK_));
}
return (char) char32;
}
/**
* Convenience method corresponding to String.valueOf(char). Returns a one or two char string
* containing the UTF-32 value in UTF16 format. If a validity check is required, use
* {@link com.ibm.icu.lang.UCharacter#isLegal(int)} on char32 before calling.
*
* @param char32 The input character.
* @return string value of char32 in UTF16 format
* @exception IllegalArgumentException Thrown if char32 is a invalid codepoint.
* @stable ICU 2.1
*/
public static String valueOf(int char32) {
if (char32 < CODEPOINT_MIN_VALUE || char32 > CODEPOINT_MAX_VALUE) {
throw new IllegalArgumentException("Illegal codepoint");
}
return toString(char32);
}
/**
* Convenience method corresponding to String.valueOf(codepoint at offset16). Returns a one or
* two char string containing the UTF-32 value in UTF16 format. If offset16 indexes a surrogate
* character, the whole supplementary codepoint will be returned. If a validity check is
* required, use {@link com.ibm.icu.lang.UCharacter#isLegal(int)} on the
* codepoint at offset16 before calling. The result returned will be a newly created String
* obtained by calling source.substring(..) with the appropriate indexes.
*
* @param source The input string.
* @param offset16 The UTF16 index to the codepoint in source
* @return string value of char32 in UTF16 format
* @stable ICU 2.1
*/
public static String valueOf(String source, int offset16) {
switch (bounds(source, offset16)) {
case LEAD_SURROGATE_BOUNDARY:
return source.substring(offset16, offset16 + 2);
case TRAIL_SURROGATE_BOUNDARY:
return source.substring(offset16 - 1, offset16 + 1);
default:
return source.substring(offset16, offset16 + 1);
}
}
/**
* Convenience method corresponding to StringBuffer.valueOf(codepoint at offset16). Returns a
* one or two char string containing the UTF-32 value in UTF16 format. If offset16 indexes a
* surrogate character, the whole supplementary codepoint will be returned. If a validity check
* is required, use {@link com.ibm.icu.lang.UCharacter#isLegal(int)} on
* the codepoint at offset16 before calling. The result returned will be a newly created String
* obtained by calling source.substring(..) with the appropriate indexes.
*
* @param source The input string buffer.
* @param offset16 The UTF16 index to the codepoint in source
* @return string value of char32 in UTF16 format
* @stable ICU 2.1
*/
public static String valueOf(StringBuffer source, int offset16) {
switch (bounds(source, offset16)) {
case LEAD_SURROGATE_BOUNDARY:
return source.substring(offset16, offset16 + 2);
case TRAIL_SURROGATE_BOUNDARY:
return source.substring(offset16 - 1, offset16 + 1);
default:
return source.substring(offset16, offset16 + 1);
}
}
/**
* Convenience method. Returns a one or two char string containing the UTF-32 value in UTF16
* format. If offset16 indexes a surrogate character, the whole supplementary codepoint will be
* returned, except when either the leading or trailing surrogate character lies out of the
* specified subarray. In the latter case, only the surrogate character within bounds will be
* returned. If a validity check is required, use
* {@link com.ibm.icu.lang.UCharacter#isLegal(int)} on the codepoint at
* offset16 before calling. The result returned will be a newly created String containing the
* relevant characters.
*
* @param source The input char array.
* @param start Start index of the subarray
* @param limit End index of the subarray
* @param offset16 The UTF16 index to the codepoint in source relative to start
* @return string value of char32 in UTF16 format
* @stable ICU 2.1
*/
public static String valueOf(char source[], int start, int limit, int offset16) {
switch (bounds(source, start, limit, offset16)) {
case LEAD_SURROGATE_BOUNDARY:
return new String(source, start + offset16, 2);
case TRAIL_SURROGATE_BOUNDARY:
return new String(source, start + offset16 - 1, 2);
}
return new String(source, start + offset16, 1);
}
/**
* Returns the UTF-16 offset that corresponds to a UTF-32 offset. Used for random access. See
* the {@link UTF16 class description} for notes on roundtripping.
*
* @param source The UTF-16 string
* @param offset32 UTF-32 offset
* @return UTF-16 offset
* @exception IndexOutOfBoundsException If offset32 is out of bounds.
* @stable ICU 2.1
*/
public static int findOffsetFromCodePoint(String source, int offset32) {
char ch;
int size = source.length(), result = 0, count = offset32;
if (offset32 < 0 || offset32 > size) {
throw new StringIndexOutOfBoundsException(offset32);
}
while (result < size && count > 0) {
ch = source.charAt(result);
if (isLeadSurrogate(ch) && ((result + 1) < size)
&& isTrailSurrogate(source.charAt(result + 1))) {
result++;
}
count--;
result++;
}
if (count != 0) {
throw new StringIndexOutOfBoundsException(offset32);
}
return result;
}
/**
* Returns the UTF-16 offset that corresponds to a UTF-32 offset. Used for random access. See
* the {@link UTF16 class description} for notes on roundtripping.
*
* @param source The UTF-16 string buffer
* @param offset32 UTF-32 offset
* @return UTF-16 offset
* @exception IndexOutOfBoundsException If offset32 is out of bounds.
* @stable ICU 2.1
*/
public static int findOffsetFromCodePoint(StringBuffer source, int offset32) {
char ch;
int size = source.length(), result = 0, count = offset32;
if (offset32 < 0 || offset32 > size) {
throw new StringIndexOutOfBoundsException(offset32);
}
while (result < size && count > 0) {
ch = source.charAt(result);
if (isLeadSurrogate(ch) && ((result + 1) < size)
&& isTrailSurrogate(source.charAt(result + 1))) {
result++;
}
count--;
result++;
}
if (count != 0) {
throw new StringIndexOutOfBoundsException(offset32);
}
return result;
}
/**
* Returns the UTF-16 offset that corresponds to a UTF-32 offset. Used for random access. See
* the {@link UTF16 class description} for notes on roundtripping.
*
* @param source The UTF-16 char array whose substring is to be analysed
* @param start Offset of the substring to be analysed
* @param limit Offset of the substring to be analysed
* @param offset32 UTF-32 offset relative to start
* @return UTF-16 offset relative to start
* @exception IndexOutOfBoundsException If offset32 is out of bounds.
* @stable ICU 2.1
*/
public static int findOffsetFromCodePoint(char source[], int start, int limit, int offset32) {
char ch;
int result = start, count = offset32;
if (offset32 > limit - start) {
throw new ArrayIndexOutOfBoundsException(offset32);
}
while (result < limit && count > 0) {
ch = source[result];
if (isLeadSurrogate(ch) && ((result + 1) < limit)
&& isTrailSurrogate(source[result + 1])) {
result++;
}
count--;
result++;
}
if (count != 0) {
throw new ArrayIndexOutOfBoundsException(offset32);
}
return result - start;
}
/**
* Returns the UTF-32 offset corresponding to the first UTF-32 boundary at or after the given
* UTF-16 offset. Used for random access. See the {@link UTF16 class description} for
* notes on roundtripping.
* Note: If the UTF-16 offset is into the middle of a surrogate pair, then the UTF-32 offset
* of the lead of the pair is returned.
*
* To find the UTF-32 length of a string, use:
*
*
* len32 = countCodePoint(source, source.length());
*
*
* @param source Text to analyse
* @param offset16 UTF-16 offset < source text length.
* @return UTF-32 offset
* @exception IndexOutOfBoundsException If offset16 is out of bounds.
* @stable ICU 2.1
*/
public static int findCodePointOffset(String source, int offset16) {
if (offset16 < 0 || offset16 > source.length()) {
throw new StringIndexOutOfBoundsException(offset16);
}
int result = 0;
char ch;
boolean hadLeadSurrogate = false;
for (int i = 0; i < offset16; ++i) {
ch = source.charAt(i);
if (hadLeadSurrogate && isTrailSurrogate(ch)) {
hadLeadSurrogate = false; // count valid trail as zero
} else {
hadLeadSurrogate = isLeadSurrogate(ch);
++result; // count others as 1
}
}
if (offset16 == source.length()) {
return result;
}
// end of source being the less significant surrogate character
// shift result back to the start of the supplementary character
if (hadLeadSurrogate && (isTrailSurrogate(source.charAt(offset16)))) {
result--;
}
return result;
}
/**
* Returns the UTF-32 offset corresponding to the first UTF-32 boundary at the given UTF-16
* offset. Used for random access. See the {@link UTF16 class description} for notes on
* roundtripping.
* Note: If the UTF-16 offset is into the middle of a surrogate pair, then the UTF-32 offset
* of the lead of the pair is returned.
*
* To find the UTF-32 length of a string, use:
*
*
* len32 = countCodePoint(source);
*
*
* @param source Text to analyse
* @param offset16 UTF-16 offset < source text length.
* @return UTF-32 offset
* @exception IndexOutOfBoundsException If offset16 is out of bounds.
* @stable ICU 2.1
*/
public static int findCodePointOffset(StringBuffer source, int offset16) {
if (offset16 < 0 || offset16 > source.length()) {
throw new StringIndexOutOfBoundsException(offset16);
}
int result = 0;
char ch;
boolean hadLeadSurrogate = false;
for (int i = 0; i < offset16; ++i) {
ch = source.charAt(i);
if (hadLeadSurrogate && isTrailSurrogate(ch)) {
hadLeadSurrogate = false; // count valid trail as zero
} else {
hadLeadSurrogate = isLeadSurrogate(ch);
++result; // count others as 1
}
}
if (offset16 == source.length()) {
return result;
}
// end of source being the less significant surrogate character
// shift result back to the start of the supplementary character
if (hadLeadSurrogate && (isTrailSurrogate(source.charAt(offset16)))) {
result--;
}
return result;
}
/**
* Returns the UTF-32 offset corresponding to the first UTF-32 boundary at the given UTF-16
* offset. Used for random access. See the {@link UTF16 class description} for notes on
* roundtripping.
* Note: If the UTF-16 offset is into the middle of a surrogate pair, then the UTF-32 offset
* of the lead of the pair is returned.
*
* To find the UTF-32 length of a substring, use:
*
*
* len32 = countCodePoint(source, start, limit);
*
*
* @param source Text to analyse
* @param start Offset of the substring
* @param limit Offset of the substring
* @param offset16 UTF-16 relative to start
* @return UTF-32 offset relative to start
* @exception IndexOutOfBoundsException If offset16 is not within the range of start and limit.
* @stable ICU 2.1
*/
public static int findCodePointOffset(char source[], int start, int limit, int offset16) {
offset16 += start;
if (offset16 > limit) {
throw new StringIndexOutOfBoundsException(offset16);
}
int result = 0;
char ch;
boolean hadLeadSurrogate = false;
for (int i = start; i < offset16; ++i) {
ch = source[i];
if (hadLeadSurrogate && isTrailSurrogate(ch)) {
hadLeadSurrogate = false; // count valid trail as zero
} else {
hadLeadSurrogate = isLeadSurrogate(ch);
++result; // count others as 1
}
}
if (offset16 == limit) {
return result;
}
// end of source being the less significant surrogate character
// shift result back to the start of the supplementary character
if (hadLeadSurrogate && (isTrailSurrogate(source[offset16]))) {
result--;
}
return result;
}
/**
* Append a single UTF-32 value to the end of a StringBuffer. If a validity check is required,
* use {@link com.ibm.icu.lang.UCharacter#isLegal(int)} on char32 before
* calling.
*
* @param target The buffer to append to
* @param char32 Value to append.
* @return the updated StringBuffer
* @exception IllegalArgumentException Thrown when char32 does not lie within the range of the Unicode codepoints
* @stable ICU 2.1
*/
public static StringBuffer append(StringBuffer target, int char32) {
// Check for irregular values
if (char32 < CODEPOINT_MIN_VALUE || char32 > CODEPOINT_MAX_VALUE) {
throw new IllegalArgumentException("Illegal codepoint: " + Integer.toHexString(char32));
}
// Write the UTF-16 values
if (char32 >= SUPPLEMENTARY_MIN_VALUE) {
target.append(getLeadSurrogate(char32));
target.append(getTrailSurrogate(char32));
} else {
target.append((char) char32);
}
return target;
}
/**
* Cover JDK 1.5 APIs. Append the code point to the buffer and return the buffer as a
* convenience.
*
* @param target The buffer to append to
* @param cp The code point to append
* @return the updated StringBuffer
* @throws IllegalArgumentException If cp is not a valid code point
* @stable ICU 3.0
*/
public static StringBuffer appendCodePoint(StringBuffer target, int cp) {
return append(target, cp);
}
/**
* Adds a codepoint to offset16 position of the argument char array.
*
* @param target Char array to be append with the new code point
* @param limit UTF16 offset which the codepoint will be appended.
* @param char32 Code point to be appended
* @return offset after char32 in the array.
* @exception IllegalArgumentException Thrown if there is not enough space for the append, or when char32 does not
* lie within the range of the Unicode codepoints.
* @stable ICU 2.1
*/
public static int append(char[] target, int limit, int char32) {
// Check for irregular values
if (char32 < CODEPOINT_MIN_VALUE || char32 > CODEPOINT_MAX_VALUE) {
throw new IllegalArgumentException("Illegal codepoint");
}
// Write the UTF-16 values
if (char32 >= SUPPLEMENTARY_MIN_VALUE) {
target[limit++] = getLeadSurrogate(char32);
target[limit++] = getTrailSurrogate(char32);
} else {
target[limit++] = (char) char32;
}
return limit;
}
/**
* Number of codepoints in a UTF16 String
*
* @param source UTF16 string
* @return number of codepoint in string
* @stable ICU 2.1
*/
public static int countCodePoint(String source) {
if (source == null || source.length() == 0) {
return 0;
}
return findCodePointOffset(source, source.length());
}
/**
* Number of codepoints in a UTF16 String buffer
*
* @param source UTF16 string buffer
* @return number of codepoint in string
* @stable ICU 2.1
*/
public static int countCodePoint(StringBuffer source) {
if (source == null || source.length() == 0) {
return 0;
}
return findCodePointOffset(source, source.length());
}
/**
* Number of codepoints in a UTF16 char array substring
*
* @param source UTF16 char array
* @param start Offset of the substring
* @param limit Offset of the substring
* @return number of codepoint in the substring
* @exception IndexOutOfBoundsException If start and limit are not valid.
* @stable ICU 2.1
*/
public static int countCodePoint(char source[], int start, int limit) {
if (source == null || source.length == 0) {
return 0;
}
return findCodePointOffset(source, start, limit, limit - start);
}
/**
* Set a code point into a UTF16 position. Adjusts target according if we are replacing a
* non-supplementary codepoint with a supplementary and vice versa.
*
* @param target Stringbuffer
* @param offset16 UTF16 position to insert into
* @param char32 Code point
* @stable ICU 2.1
*/
public static void setCharAt(StringBuffer target, int offset16, int char32) {
int count = 1;
char single = target.charAt(offset16);
if (isSurrogate(single)) {
// pairs of the surrogate with offset16 at the lead char found
if (isLeadSurrogate(single) && (target.length() > offset16 + 1)
&& isTrailSurrogate(target.charAt(offset16 + 1))) {
count++;
} else {
// pairs of the surrogate with offset16 at the trail char
// found
if (isTrailSurrogate(single) && (offset16 > 0)
&& isLeadSurrogate(target.charAt(offset16 - 1))) {
offset16--;
count++;
}
}
}
target.replace(offset16, offset16 + count, valueOf(char32));
}
/**
* Set a code point into a UTF16 position in a char array. Adjusts target according if we are
* replacing a non-supplementary codepoint with a supplementary and vice versa.
*
* @param target char array
* @param limit numbers of valid chars in target, different from target.length. limit counts the
* number of chars in target that represents a string, not the size of array target.
* @param offset16 UTF16 position to insert into
* @param char32 code point
* @return new number of chars in target that represents a string
* @exception IndexOutOfBoundsException if offset16 is out of range
* @stable ICU 2.1
*/
public static int setCharAt(char target[], int limit, int offset16, int char32) {
if (offset16 >= limit) {
throw new ArrayIndexOutOfBoundsException(offset16);
}
int count = 1;
char single = target[offset16];
if (isSurrogate(single)) {
// pairs of the surrogate with offset16 at the lead char found
if (isLeadSurrogate(single) && (target.length > offset16 + 1)
&& isTrailSurrogate(target[offset16 + 1])) {
count++;
} else {
// pairs of the surrogate with offset16 at the trail char
// found
if (isTrailSurrogate(single) && (offset16 > 0)
&& isLeadSurrogate(target[offset16 - 1])) {
offset16--;
count++;
}
}
}
String str = valueOf(char32);
int result = limit;
int strlength = str.length();
target[offset16] = str.charAt(0);
if (count == strlength) {
if (count == 2) {
target[offset16 + 1] = str.charAt(1);
}
} else {
// this is not exact match in space, we'll have to do some
// shifting
System.arraycopy(target, offset16 + count, target, offset16 + strlength, limit
- (offset16 + count));
if (count < strlength) {
// char32 is a supplementary character trying to squeeze into
// a non-supplementary space
target[offset16 + 1] = str.charAt(1);
result++;
if (result < target.length) {
target[result] = 0;
}
} else {
// char32 is a non-supplementary character trying to fill
// into a supplementary space
result--;
target[result] = 0;
}
}
return result;
}
/**
* Shifts offset16 by the argument number of codepoints
*
* @param source string
* @param offset16 UTF16 position to shift
* @param shift32 number of codepoints to shift
* @return new shifted offset16
* @exception IndexOutOfBoundsException if the new offset16 is out of bounds.
* @stable ICU 2.1
*/
public static int moveCodePointOffset(String source, int offset16, int shift32) {
int result = offset16;
int size = source.length();
int count;
char ch;
if (offset16 < 0 || offset16 > size) {
throw new StringIndexOutOfBoundsException(offset16);
}
if (shift32 > 0) {
if (shift32 + offset16 > size) {
throw new StringIndexOutOfBoundsException(offset16);
}
count = shift32;
while (result < size && count > 0) {
ch = source.charAt(result);
if (isLeadSurrogate(ch) && ((result + 1) < size)
&& isTrailSurrogate(source.charAt(result + 1))) {
result++;
}
count--;
result++;
}
} else {
if (offset16 + shift32 < 0) {
throw new StringIndexOutOfBoundsException(offset16);
}
for (count = -shift32; count > 0; count--) {
result--;
if (result < 0) {
break;
}
ch = source.charAt(result);
if (isTrailSurrogate(ch) && result > 0
&& isLeadSurrogate(source.charAt(result - 1))) {
result--;
}
}
}
if (count != 0) {
throw new StringIndexOutOfBoundsException(shift32);
}
return result;
}
/**
* Shifts offset16 by the argument number of codepoints
*
* @param source String buffer
* @param offset16 UTF16 position to shift
* @param shift32 Number of codepoints to shift
* @return new shifted offset16
* @exception IndexOutOfBoundsException If the new offset16 is out of bounds.
* @stable ICU 2.1
*/
public static int moveCodePointOffset(StringBuffer source, int offset16, int shift32) {
int result = offset16;
int size = source.length();
int count;
char ch;
if (offset16 < 0 || offset16 > size) {
throw new StringIndexOutOfBoundsException(offset16);
}
if (shift32 > 0) {
if (shift32 + offset16 > size) {
throw new StringIndexOutOfBoundsException(offset16);
}
count = shift32;
while (result < size && count > 0) {
ch = source.charAt(result);
if (isLeadSurrogate(ch) && ((result + 1) < size)
&& isTrailSurrogate(source.charAt(result + 1))) {
result++;
}
count--;
result++;
}
} else {
if (offset16 + shift32 < 0) {
throw new StringIndexOutOfBoundsException(offset16);
}
for (count = -shift32; count > 0; count--) {
result--;
if (result < 0) {
break;
}
ch = source.charAt(result);
if (isTrailSurrogate(ch) && result > 0
&& isLeadSurrogate(source.charAt(result - 1))) {
result--;
}
}
}
if (count != 0) {
throw new StringIndexOutOfBoundsException(shift32);
}
return result;
}
/**
* Shifts offset16 by the argument number of codepoints within a subarray.
*
* @param source Char array
* @param start Position of the subarray to be performed on
* @param limit Position of the subarray to be performed on
* @param offset16 UTF16 position to shift relative to start
* @param shift32 Number of codepoints to shift
* @return new shifted offset16 relative to start
* @exception IndexOutOfBoundsException If the new offset16 is out of bounds with respect to the subarray or the
* subarray bounds are out of range.
* @stable ICU 2.1
*/
public static int moveCodePointOffset(char source[], int start, int limit, int offset16,
int shift32) {
int size = source.length;
int count;
char ch;
int result = offset16 + start;
if (start < 0 || limit < start) {
throw new StringIndexOutOfBoundsException(start);
}
if (limit > size) {
throw new StringIndexOutOfBoundsException(limit);
}
if (offset16 < 0 || result > limit) {
throw new StringIndexOutOfBoundsException(offset16);
}
if (shift32 > 0) {
if (shift32 + result > size) {
throw new StringIndexOutOfBoundsException(result);
}
count = shift32;
while (result < limit && count > 0) {
ch = source[result];
if (isLeadSurrogate(ch) && (result + 1 < limit)
&& isTrailSurrogate(source[result + 1])) {
result++;
}
count--;
result++;
}
} else {
if (result + shift32 < start) {
throw new StringIndexOutOfBoundsException(result);
}
for (count = -shift32; count > 0; count--) {
result--;
if (result < start) {
break;
}
ch = source[result];
if (isTrailSurrogate(ch) && result > start && isLeadSurrogate(source[result - 1])) {
result--;
}
}
}
if (count != 0) {
throw new StringIndexOutOfBoundsException(shift32);
}
result -= start;
return result;
}
/**
* Inserts char32 codepoint into target at the argument offset16. If the offset16 is in the
* middle of a supplementary codepoint, char32 will be inserted after the supplementary
* codepoint. The length of target increases by one if codepoint is non-supplementary, 2
* otherwise.
*
* The overall effect is exactly as if the argument were converted to a string by the method
* valueOf(char) and the characters in that string were then inserted into target at the
* position indicated by offset16.
*
*
* The offset argument must be greater than or equal to 0, and less than or equal to the length
* of source.
*
* @param target String buffer to insert to
* @param offset16 Offset which char32 will be inserted in
* @param char32 Codepoint to be inserted
* @return a reference to target
* @exception IndexOutOfBoundsException Thrown if offset16 is invalid.
* @stable ICU 2.1
*/
public static StringBuffer insert(StringBuffer target, int offset16, int char32) {
String str = valueOf(char32);
if (offset16 != target.length() && bounds(target, offset16) == TRAIL_SURROGATE_BOUNDARY) {
offset16++;
}
target.insert(offset16, str);
return target;
}
/**
* Inserts char32 codepoint into target at the argument offset16. If the offset16 is in the
* middle of a supplementary codepoint, char32 will be inserted after the supplementary
* codepoint. Limit increases by one if codepoint is non-supplementary, 2 otherwise.
*
* The overall effect is exactly as if the argument were converted to a string by the method
* valueOf(char) and the characters in that string were then inserted into target at the
* position indicated by offset16.
*
*
* The offset argument must be greater than or equal to 0, and less than or equal to the limit.
*
* @param target Char array to insert to
* @param limit End index of the char array, limit <= target.length
* @param offset16 Offset which char32 will be inserted in
* @param char32 Codepoint to be inserted
* @return new limit size
* @exception IndexOutOfBoundsException Thrown if offset16 is invalid.
* @stable ICU 2.1
*/
public static int insert(char target[], int limit, int offset16, int char32) {
String str = valueOf(char32);
if (offset16 != limit && bounds(target, 0, limit, offset16) == TRAIL_SURROGATE_BOUNDARY) {
offset16++;
}
int size = str.length();
if (limit + size > target.length) {
throw new ArrayIndexOutOfBoundsException(offset16 + size);
}
System.arraycopy(target, offset16, target, offset16 + size, limit - offset16);
target[offset16] = str.charAt(0);
if (size == 2) {
target[offset16 + 1] = str.charAt(1);
}
return limit + size;
}
/**
* Removes the codepoint at the specified position in this target (shortening target by 1
* character if the codepoint is a non-supplementary, 2 otherwise).
*
* @param target String buffer to remove codepoint from
* @param offset16 Offset which the codepoint will be removed
* @return a reference to target
* @exception IndexOutOfBoundsException Thrown if offset16 is invalid.
* @stable ICU 2.1
*/
public static StringBuffer delete(StringBuffer target, int offset16) {
int count = 1;
switch (bounds(target, offset16)) {
case LEAD_SURROGATE_BOUNDARY:
count++;
break;
case TRAIL_SURROGATE_BOUNDARY:
count++;
offset16--;
break;
}
target.delete(offset16, offset16 + count);
return target;
}
/**
* Removes the codepoint at the specified position in this target (shortening target by 1
* character if the codepoint is a non-supplementary, 2 otherwise).
*
* @param target String buffer to remove codepoint from
* @param limit End index of the char array, limit <= target.length
* @param offset16 Offset which the codepoint will be removed
* @return a new limit size
* @exception IndexOutOfBoundsException Thrown if offset16 is invalid.
* @stable ICU 2.1
*/
public static int delete(char target[], int limit, int offset16) {
int count = 1;
switch (bounds(target, 0, limit, offset16)) {
case LEAD_SURROGATE_BOUNDARY:
count++;
break;
case TRAIL_SURROGATE_BOUNDARY:
count++;
offset16--;
break;
}
System.arraycopy(target, offset16 + count, target, offset16, limit - (offset16 + count));
target[limit - count] = 0;
return limit - count;
}
/**
* Returns the index within the argument UTF16 format Unicode string of the first occurrence of
* the argument codepoint. I.e., the smallest index i such that
* UTF16.charAt(source, i) ==
* char32 is true.
*
* If no such character occurs in this string, then -1 is returned.
*
*
* Examples:
* UTF16.indexOf("abc", 'a') returns 0
* UTF16.indexOf("abc\ud800\udc00", 0x10000) returns 3
* UTF16.indexOf("abc\ud800\udc00", 0xd800) returns -1
*
* Note this method is provided as support to jdk 1.3, which does not support supplementary
* characters to its fullest.
*
* @param source UTF16 format Unicode string that will be searched
* @param char32 Codepoint to search for
* @return the index of the first occurrence of the codepoint in the argument Unicode string, or
* -1 if the codepoint does not occur.
* @stable ICU 2.6
*/
public static int indexOf(String source, int char32) {
if (char32 < CODEPOINT_MIN_VALUE || char32 > CODEPOINT_MAX_VALUE) {
throw new IllegalArgumentException("Argument char32 is not a valid codepoint");
}
// non-surrogate bmp
if (char32 < LEAD_SURROGATE_MIN_VALUE
|| (char32 > TRAIL_SURROGATE_MAX_VALUE && char32 < SUPPLEMENTARY_MIN_VALUE)) {
return source.indexOf((char) char32);
}
// surrogate
if (char32 < SUPPLEMENTARY_MIN_VALUE) {
int result = source.indexOf((char) char32);
if (result >= 0) {
if (isLeadSurrogate(char32) && (result < source.length() - 1)
&& isTrailSurrogate(source.charAt(result + 1))) {
return indexOf(source, char32, result + 1);
}
// trail surrogate
if (result > 0 && isLeadSurrogate(source.charAt(result - 1))) {
return indexOf(source, char32, result + 1);
}
}
return result;
}
// supplementary
String char32str = toString(char32);
return source.indexOf(char32str);
}
/**
* Returns the index within the argument UTF16 format Unicode string of the first occurrence of
* the argument string str. This method is implemented based on codepoints, hence a "lead
* surrogate character + trail surrogate character" is treated as one entity.e Hence if the str
* starts with trail surrogate character at index 0, a source with a leading a surrogate
* character before str found at in source will not have a valid match. Vice versa for lead
* surrogates that ends str. See example below.
*
* If no such string str occurs in this source, then -1 is returned.
*
*
* Examples:
* UTF16.indexOf("abc", "ab") returns 0
* UTF16.indexOf("abc\ud800\udc00", "\ud800\udc00") returns 3
* UTF16.indexOf("abc\ud800\udc00", "\ud800") returns -1
*
* Note this method is provided as support to jdk 1.3, which does not support supplementary
* characters to its fullest.
*
* @param source UTF16 format Unicode string that will be searched
* @param str UTF16 format Unicode string to search for
* @return the index of the first occurrence of the codepoint in the argument Unicode string, or
* -1 if the codepoint does not occur.
* @stable ICU 2.6
*/
public static int indexOf(String source, String str) {
int strLength = str.length();
// non-surrogate ends
if (!isTrailSurrogate(str.charAt(0)) && !isLeadSurrogate(str.charAt(strLength - 1))) {
return source.indexOf(str);
}
int result = source.indexOf(str);
int resultEnd = result + strLength;
if (result >= 0) {
// check last character
if (isLeadSurrogate(str.charAt(strLength - 1)) && (result < source.length() - 1)
&& isTrailSurrogate(source.charAt(resultEnd + 1))) {
return indexOf(source, str, resultEnd + 1);
}
// check first character which is a trail surrogate
if (isTrailSurrogate(str.charAt(0)) && result > 0
&& isLeadSurrogate(source.charAt(result - 1))) {
return indexOf(source, str, resultEnd + 1);
}
}
return result;
}
/**
* Returns the index within the argument UTF16 format Unicode string of the first occurrence of
* the argument codepoint. I.e., the smallest index i such that:
* (UTF16.charAt(source, i) == char32 && i >= fromIndex) is true.
*
* If no such character occurs in this string, then -1 is returned.
*
*
* Examples:
* UTF16.indexOf("abc", 'a', 1) returns -1
* UTF16.indexOf("abc\ud800\udc00", 0x10000, 1) returns 3
* UTF16.indexOf("abc\ud800\udc00", 0xd800, 1) returns -1
*
* Note this method is provided as support to jdk 1.3, which does not support supplementary
* characters to its fullest.
*
* @param source UTF16 format Unicode string that will be searched
* @param char32 Codepoint to search for
* @param fromIndex The index to start the search from.
* @return the index of the first occurrence of the codepoint in the argument Unicode string at
* or after fromIndex, or -1 if the codepoint does not occur.
* @stable ICU 2.6
*/
public static int indexOf(String source, int char32, int fromIndex) {
if (char32 < CODEPOINT_MIN_VALUE || char32 > CODEPOINT_MAX_VALUE) {
throw new IllegalArgumentException("Argument char32 is not a valid codepoint");
}
// non-surrogate bmp
if (char32 < LEAD_SURROGATE_MIN_VALUE
|| (char32 > TRAIL_SURROGATE_MAX_VALUE && char32 < SUPPLEMENTARY_MIN_VALUE)) {
return source.indexOf((char) char32, fromIndex);
}
// surrogate
if (char32 < SUPPLEMENTARY_MIN_VALUE) {
int result = source.indexOf((char) char32, fromIndex);
if (result >= 0) {
if (isLeadSurrogate(char32) && (result < source.length() - 1)
&& isTrailSurrogate(source.charAt(result + 1))) {
return indexOf(source, char32, result + 1);
}
// trail surrogate
if (result > 0 && isLeadSurrogate(source.charAt(result - 1))) {
return indexOf(source, char32, result + 1);
}
}
return result;
}
// supplementary
String char32str = toString(char32);
return source.indexOf(char32str, fromIndex);
}
/**
* Returns the index within the argument UTF16 format Unicode string of the first occurrence of
* the argument string str. This method is implemented based on codepoints, hence a "lead
* surrogate character + trail surrogate character" is treated as one entity.e Hence if the str
* starts with trail surrogate character at index 0, a source with a leading a surrogate
* character before str found at in source will not have a valid match. Vice versa for lead
* surrogates that ends str. See example below.
*
* If no such string str occurs in this source, then -1 is returned.
*
*
* Examples:
* UTF16.indexOf("abc", "ab", 0) returns 0
* UTF16.indexOf("abc\ud800\udc00", "\ud800\udc00", 0) returns 3
* UTF16.indexOf("abc\ud800\udc00", "\ud800\udc00", 2) returns 3
* UTF16.indexOf("abc\ud800\udc00", "\ud800", 0) returns -1
*
* Note this method is provided as support to jdk 1.3, which does not support supplementary
* characters to its fullest.
*
* @param source UTF16 format Unicode string that will be searched
* @param str UTF16 format Unicode string to search for
* @param fromIndex The index to start the search from.
* @return the index of the first occurrence of the codepoint in the argument Unicode string, or
* -1 if the codepoint does not occur.
* @stable ICU 2.6
*/
public static int indexOf(String source, String str, int fromIndex) {
int strLength = str.length();
// non-surrogate ends
if (!isTrailSurrogate(str.charAt(0)) && !isLeadSurrogate(str.charAt(strLength - 1))) {
return source.indexOf(str, fromIndex);
}
int result = source.indexOf(str, fromIndex);
int resultEnd = result + strLength;
if (result >= 0) {
// check last character
if (isLeadSurrogate(str.charAt(strLength - 1)) && (result < source.length() - 1)
&& isTrailSurrogate(source.charAt(resultEnd))) {
return indexOf(source, str, resultEnd + 1);
}
// check first character which is a trail surrogate
if (isTrailSurrogate(str.charAt(0)) && result > 0
&& isLeadSurrogate(source.charAt(result - 1))) {
return indexOf(source, str, resultEnd + 1);
}
}
return result;
}
/**
* Returns the index within the argument UTF16 format Unicode string of the last occurrence of
* the argument codepoint. I.e., the index returned is the largest value i such that:
* UTF16.charAt(source, i) == char32 is true.
*
* Examples:
* UTF16.lastIndexOf("abc", 'a') returns 0
* UTF16.lastIndexOf("abc\ud800\udc00", 0x10000) returns 3
* UTF16.lastIndexOf("abc\ud800\udc00", 0xd800) returns -1
*
*
* source is searched backwards starting at the last character.
*
* Note this method is provided as support to jdk 1.3, which does not support supplementary
* characters to its fullest.
*
* @param source UTF16 format Unicode string that will be searched
* @param char32 Codepoint to search for
* @return the index of the last occurrence of the codepoint in source, or -1 if the codepoint
* does not occur.
* @stable ICU 2.6
*/
public static int lastIndexOf(String source, int char32) {
if (char32 < CODEPOINT_MIN_VALUE || char32 > CODEPOINT_MAX_VALUE) {
throw new IllegalArgumentException("Argument char32 is not a valid codepoint");
}
// non-surrogate bmp
if (char32 < LEAD_SURROGATE_MIN_VALUE
|| (char32 > TRAIL_SURROGATE_MAX_VALUE && char32 < SUPPLEMENTARY_MIN_VALUE)) {
return source.lastIndexOf((char) char32);
}
// surrogate
if (char32 < SUPPLEMENTARY_MIN_VALUE) {
int result = source.lastIndexOf((char) char32);
if (result >= 0) {
if (isLeadSurrogate(char32) && (result < source.length() - 1)
&& isTrailSurrogate(source.charAt(result + 1))) {
return lastIndexOf(source, char32, result - 1);
}
// trail surrogate
if (result > 0 && isLeadSurrogate(source.charAt(result - 1))) {
return lastIndexOf(source, char32, result - 1);
}
}
return result;
}
// supplementary
String char32str = toString(char32);
return source.lastIndexOf(char32str);
}
/**
* Returns the index within the argument UTF16 format Unicode string of the last occurrence of
* the argument string str. This method is implemented based on codepoints, hence a "lead
* surrogate character + trail surrogate character" is treated as one entity.e Hence if the str
* starts with trail surrogate character at index 0, a source with a leading a surrogate
* character before str found at in source will not have a valid match. Vice versa for lead
* surrogates that ends str. See example below.
*
* Examples:
* UTF16.lastIndexOf("abc", "a") returns 0
* UTF16.lastIndexOf("abc\ud800\udc00", "\ud800\udc00") returns 3
* UTF16.lastIndexOf("abc\ud800\udc00", "\ud800") returns -1
*
*
* source is searched backwards starting at the last character.
*
* Note this method is provided as support to jdk 1.3, which does not support supplementary
* characters to its fullest.
*
* @param source UTF16 format Unicode string that will be searched
* @param str UTF16 format Unicode string to search for
* @return the index of the last occurrence of the codepoint in source, or -1 if the codepoint
* does not occur.
* @stable ICU 2.6
*/
public static int lastIndexOf(String source, String str) {
int strLength = str.length();
// non-surrogate ends
if (!isTrailSurrogate(str.charAt(0)) && !isLeadSurrogate(str.charAt(strLength - 1))) {
return source.lastIndexOf(str);
}
int result = source.lastIndexOf(str);
if (result >= 0) {
// check last character
if (isLeadSurrogate(str.charAt(strLength - 1)) && (result < source.length() - 1)
&& isTrailSurrogate(source.charAt(result + strLength + 1))) {
return lastIndexOf(source, str, result - 1);
}
// check first character which is a trail surrogate
if (isTrailSurrogate(str.charAt(0)) && result > 0
&& isLeadSurrogate(source.charAt(result - 1))) {
return lastIndexOf(source, str, result - 1);
}
}
return result;
}
/**
*
* Returns the index within the argument UTF16 format Unicode string of the last occurrence of
* the argument codepoint, where the result is less than or equals to fromIndex.
*
*
* This method is implemented based on codepoints, hence a single surrogate character will not
* match a supplementary character.
*
*
* source is searched backwards starting at the last character starting at the specified index.
*
*
* Examples:
* UTF16.lastIndexOf("abc", 'c', 2) returns 2
* UTF16.lastIndexOf("abc", 'c', 1) returns -1
* UTF16.lastIndexOf("abc\ud800\udc00", 0x10000, 5) returns 3
* UTF16.lastIndexOf("abc\ud800\udc00", 0x10000, 3) returns 3
* UTF16.lastIndexOf("abc\ud800\udc00", 0xd800) returns -1
*
* Note this method is provided as support to jdk 1.3, which does not support supplementary
* characters to its fullest.
*
* @param source UTF16 format Unicode string that will be searched
* @param char32 Codepoint to search for
* @param fromIndex the index to start the search from. There is no restriction on the value of
* fromIndex. If it is greater than or equal to the length of this string, it has the
* same effect as if it were equal to one less than the length of this string: this
* entire string may be searched. If it is negative, it has the same effect as if it
* were -1: -1 is returned.
* @return the index of the last occurrence of the codepoint in source, or -1 if the codepoint
* does not occur.
* @stable ICU 2.6
*/
public static int lastIndexOf(String source, int char32, int fromIndex) {
if (char32 < CODEPOINT_MIN_VALUE || char32 > CODEPOINT_MAX_VALUE) {
throw new IllegalArgumentException("Argument char32 is not a valid codepoint");
}
// non-surrogate bmp
if (char32 < LEAD_SURROGATE_MIN_VALUE
|| (char32 > TRAIL_SURROGATE_MAX_VALUE && char32 < SUPPLEMENTARY_MIN_VALUE)) {
return source.lastIndexOf((char) char32, fromIndex);
}
// surrogate
if (char32 < SUPPLEMENTARY_MIN_VALUE) {
int result = source.lastIndexOf((char) char32, fromIndex);
if (result >= 0) {
if (isLeadSurrogate(char32) && (result < source.length() - 1)
&& isTrailSurrogate(source.charAt(result + 1))) {
return lastIndexOf(source, char32, result - 1);
}
// trail surrogate
if (result > 0 && isLeadSurrogate(source.charAt(result - 1))) {
return lastIndexOf(source, char32, result - 1);
}
}
return result;
}
// supplementary
String char32str = toString(char32);
return source.lastIndexOf(char32str, fromIndex);
}
/**
*
* Returns the index within the argument UTF16 format Unicode string of the last occurrence of
* the argument string str, where the result is less than or equals to fromIndex.
*
*
* This method is implemented based on codepoints, hence a "lead surrogate character + trail
* surrogate character" is treated as one entity. Hence if the str starts with trail surrogate
* character at index 0, a source with a leading a surrogate character before str found at in
* source will not have a valid match. Vice versa for lead surrogates that ends str.
*
* See example below.
*
* Examples:
* UTF16.lastIndexOf("abc", "c", 2) returns 2
* UTF16.lastIndexOf("abc", "c", 1) returns -1
* UTF16.lastIndexOf("abc\ud800\udc00", "\ud800\udc00", 5) returns 3
* UTF16.lastIndexOf("abc\ud800\udc00", "\ud800\udc00", 3) returns 3
* UTF16.lastIndexOf("abc\ud800\udc00", "\ud800", 4) returns -1
*
*
* source is searched backwards starting at the last character.
*
* Note this method is provided as support to jdk 1.3, which does not support supplementary
* characters to its fullest.
*
* @param source UTF16 format Unicode string that will be searched
* @param str UTF16 format Unicode string to search for
* @param fromIndex the index to start the search from. There is no restriction on the value of
* fromIndex. If it is greater than or equal to the length of this string, it has the
* same effect as if it were equal to one less than the length of this string: this
* entire string may be searched. If it is negative, it has the same effect as if it
* were -1: -1 is returned.
* @return the index of the last occurrence of the codepoint in source, or -1 if the codepoint
* does not occur.
* @stable ICU 2.6
*/
public static int lastIndexOf(String source, String str, int fromIndex) {
int strLength = str.length();
// non-surrogate ends
if (!isTrailSurrogate(str.charAt(0)) && !isLeadSurrogate(str.charAt(strLength - 1))) {
return source.lastIndexOf(str, fromIndex);
}
int result = source.lastIndexOf(str, fromIndex);
if (result >= 0) {
// check last character
if (isLeadSurrogate(str.charAt(strLength - 1)) && (result < source.length() - 1)
&& isTrailSurrogate(source.charAt(result + strLength))) {
return lastIndexOf(source, str, result - 1);
}
// check first character which is a trail surrogate
if (isTrailSurrogate(str.charAt(0)) && result > 0
&& isLeadSurrogate(source.charAt(result - 1))) {
return lastIndexOf(source, str, result - 1);
}
}
return result;
}
/**
* Returns a new UTF16 format Unicode string resulting from replacing all occurrences of
* oldChar32 in source with newChar32. If the character oldChar32 does not occur in the UTF16
* format Unicode string source, then source will be returned. Otherwise, a new String object is
* created that represents a codepoint sequence identical to the codepoint sequence represented
* by source, except that every occurrence of oldChar32 is replaced by an occurrence of
* newChar32.
*
* Examples:
* UTF16.replace("mesquite in your cellar", 'e', 'o');
* returns "mosquito in your collar"
* UTF16.replace("JonL", 'q', 'x');
* returns "JonL" (no change)
* UTF16.replace("Supplementary character \ud800\udc00", 0x10000, '!');
* returns "Supplementary character !"
* UTF16.replace("Supplementary character \ud800\udc00", 0xd800, '!');
* returns "Supplementary character \ud800\udc00"
*
* Note this method is provided as support to jdk 1.3, which does not support supplementary
* characters to its fullest.
*
* @param source UTF16 format Unicode string which the codepoint replacements will be based on.
* @param oldChar32 Non-zero old codepoint to be replaced.
* @param newChar32 The new codepoint to replace oldChar32
* @return new String derived from source by replacing every occurrence of oldChar32 with
* newChar32, unless when no oldChar32 is found in source then source will be returned.
* @stable ICU 2.6
*/
public static String replace(String source, int oldChar32, int newChar32) {
if (oldChar32 <= 0 || oldChar32 > CODEPOINT_MAX_VALUE) {
throw new IllegalArgumentException("Argument oldChar32 is not a valid codepoint");
}
if (newChar32 <= 0 || newChar32 > CODEPOINT_MAX_VALUE) {
throw new IllegalArgumentException("Argument newChar32 is not a valid codepoint");
}
int index = indexOf(source, oldChar32);
if (index == -1) {
return source;
}
String newChar32Str = toString(newChar32);
int oldChar32Size = 1;
int newChar32Size = newChar32Str.length();
StringBuffer result = new StringBuffer(source);
int resultIndex = index;
if (oldChar32 >= SUPPLEMENTARY_MIN_VALUE) {
oldChar32Size = 2;
}
while (index != -1) {
int endResultIndex = resultIndex + oldChar32Size;
result.replace(resultIndex, endResultIndex, newChar32Str);
int lastEndIndex = index + oldChar32Size;
index = indexOf(source, oldChar32, lastEndIndex);
resultIndex += newChar32Size + index - lastEndIndex;
}
return result.toString();
}
/**
* Returns a new UTF16 format Unicode string resulting from replacing all occurrences of oldStr
* in source with newStr. If the string oldStr does not occur in the UTF16 format Unicode string
* source, then source will be returned. Otherwise, a new String object is created that
* represents a codepoint sequence identical to the codepoint sequence represented by source,
* except that every occurrence of oldStr is replaced by an occurrence of newStr.
*
* Examples:
* UTF16.replace("mesquite in your cellar", "e", "o");
* returns "mosquito in your collar"
* UTF16.replace("mesquite in your cellar", "mesquite", "cat");
* returns "cat in your cellar"
* UTF16.replace("JonL", "q", "x");
* returns "JonL" (no change)
* UTF16.replace("Supplementary character \ud800\udc00", "\ud800\udc00", '!');
* returns "Supplementary character !"
* UTF16.replace("Supplementary character \ud800\udc00", "\ud800", '!');
* returns "Supplementary character \ud800\udc00"
*
* Note this method is provided as support to jdk 1.3, which does not support supplementary
* characters to its fullest.
*
* @param source UTF16 format Unicode string which the replacements will be based on.
* @param oldStr Non-zero-length string to be replaced.
* @param newStr The new string to replace oldStr
* @return new String derived from source by replacing every occurrence of oldStr with newStr.
* When no oldStr is found in source, then source will be returned.
* @stable ICU 2.6
*/
public static String replace(String source, String oldStr, String newStr) {
int index = indexOf(source, oldStr);
if (index == -1) {
return source;
}
int oldStrSize = oldStr.length();
int newStrSize = newStr.length();
StringBuffer result = new StringBuffer(source);
int resultIndex = index;
while (index != -1) {
int endResultIndex = resultIndex + oldStrSize;
result.replace(resultIndex, endResultIndex, newStr);
int lastEndIndex = index + oldStrSize;
index = indexOf(source, oldStr, lastEndIndex);
resultIndex += newStrSize + index - lastEndIndex;
}
return result.toString();
}
/**
* Reverses a UTF16 format Unicode string and replaces source's content with it. This method
* will reverse surrogate characters correctly, instead of blindly reversing every character.
*
* Examples:
* UTF16.reverse(new StringBuffer( "Supplementary characters \ud800\udc00\ud801\udc01"))
* returns "\ud801\udc01\ud800\udc00 sretcarahc yratnemelppuS".
*
* @param source The source StringBuffer that contains UTF16 format Unicode string to be reversed
* @return a modified source with reversed UTF16 format Unicode string.
* @stable ICU 2.6
*/
public static StringBuffer reverse(StringBuffer source) {
int length = source.length();
StringBuffer result = new StringBuffer(length);
for (int i = length; i-- > 0;) {
char ch = source.charAt(i);
if (isTrailSurrogate(ch) && i > 0) {
char ch2 = source.charAt(i - 1);
if (isLeadSurrogate(ch2)) {
result.append(ch2);
result.append(ch);
--i;
continue;
}
}
result.append(ch);
}
return result;
}
/**
* Check if the string contains more Unicode code points than a certain number. This is more
* efficient than counting all code points in the entire string and comparing that number with a
* threshold. This function may not need to scan the string at all if the length is within a
* certain range, and never needs to count more than 'number + 1' code points. Logically
* equivalent to (countCodePoint(s) > number). A Unicode code point may occupy either one or two
* code units.
*
* @param source The input string.
* @param number The number of code points in the string is compared against the 'number'
* parameter.
* @return boolean value for whether the string contains more Unicode code points than 'number'.
* @stable ICU 2.4
*/
public static boolean hasMoreCodePointsThan(String source, int number) {
if (number < 0) {
return true;
}
if (source == null) {
return false;
}
int length = source.length();
// length >= 0 known
// source contains at least (length + 1) / 2 code points: <= 2
// chars per cp
if (((length + 1) >> 1) > number) {
return true;
}
// check if source does not even contain enough chars
int maxsupplementary = length - number;
if (maxsupplementary <= 0) {
return false;
}
// there are maxsupplementary = length - number more chars than
// asked-for code points
// count code points until they exceed and also check that there are
// no more than maxsupplementary supplementary code points (char pairs)
int start = 0;
while (true) {
if (length == 0) {
return false;
}
if (number == 0) {
return true;
}
if (isLeadSurrogate(source.charAt(start++)) && start != length
&& isTrailSurrogate(source.charAt(start))) {
start++;
if (--maxsupplementary <= 0) {
// too many pairs - too few code points
return false;
}
}
--number;
}
}
/**
* Check if the sub-range of char array, from argument start to limit, contains more Unicode
* code points than a certain number. This is more efficient than counting all code points in
* the entire char array range and comparing that number with a threshold. This function may not
* need to scan the char array at all if start and limit is within a certain range, and never
* needs to count more than 'number + 1' code points. Logically equivalent to
* (countCodePoint(source, start, limit) > number). A Unicode code point may occupy either one
* or two code units.
*
* @param source Array of UTF-16 chars
* @param start Offset to substring in the source array for analyzing
* @param limit Offset to substring in the source array for analyzing
* @param number The number of code points in the string is compared against the 'number'
* parameter.
* @return boolean value for whether the string contains more Unicode code points than 'number'.
* @exception IndexOutOfBoundsException Thrown when limit < start
* @stable ICU 2.4
*/
public static boolean hasMoreCodePointsThan(char source[], int start, int limit, int number) {
int length = limit - start;
if (length < 0 || start < 0 || limit < 0) {
throw new IndexOutOfBoundsException(
"Start and limit indexes should be non-negative and start <= limit");
}
if (number < 0) {
return true;
}
if (source == null) {
return false;
}
// length >= 0 known
// source contains at least (length + 1) / 2 code points: <= 2
// chars per cp
if (((length + 1) >> 1) > number) {
return true;
}
// check if source does not even contain enough chars
int maxsupplementary = length - number;
if (maxsupplementary <= 0) {
return false;
}
// there are maxsupplementary = length - number more chars than
// asked-for code points
// count code points until they exceed and also check that there are
// no more than maxsupplementary supplementary code points (char pairs)
while (true) {
if (length == 0) {
return false;
}
if (number == 0) {
return true;
}
if (isLeadSurrogate(source[start++]) && start != limit
&& isTrailSurrogate(source[start])) {
start++;
if (--maxsupplementary <= 0) {
// too many pairs - too few code points
return false;
}
}
--number;
}
}
/**
* Check if the string buffer contains more Unicode code points than a certain number. This is
* more efficient than counting all code points in the entire string buffer and comparing that
* number with a threshold. This function may not need to scan the string buffer at all if the
* length is within a certain range, and never needs to count more than 'number + 1' code
* points. Logically equivalent to (countCodePoint(s) > number). A Unicode code point may
* occupy either one or two code units.
*
* @param source The input string buffer.
* @param number The number of code points in the string buffer is compared against the 'number'
* parameter.
* @return boolean value for whether the string buffer contains more Unicode code points than
* 'number'.
* @stable ICU 2.4
*/
public static boolean hasMoreCodePointsThan(StringBuffer source, int number) {
if (number < 0) {
return true;
}
if (source == null) {
return false;
}
int length = source.length();
// length >= 0 known
// source contains at least (length + 1) / 2 code points: <= 2
// chars per cp
if (((length + 1) >> 1) > number) {
return true;
}
// check if source does not even contain enough chars
int maxsupplementary = length - number;
if (maxsupplementary <= 0) {
return false;
}
// there are maxsupplementary = length - number more chars than
// asked-for code points
// count code points until they exceed and also check that there are
// no more than maxsupplementary supplementary code points (char pairs)
int start = 0;
while (true) {
if (length == 0) {
return false;
}
if (number == 0) {
return true;
}
if (isLeadSurrogate(source.charAt(start++)) && start != length
&& isTrailSurrogate(source.charAt(start))) {
start++;
if (--maxsupplementary <= 0) {
// too many pairs - too few code points
return false;
}
}
--number;
}
}
/**
* Cover JDK 1.5 API. Create a String from an array of codePoints.
*
* @param codePoints The code array
* @param offset The start of the text in the code point array
* @param count The number of code points
* @return a String representing the code points between offset and count
* @throws IllegalArgumentException If an invalid code point is encountered
* @throws IndexOutOfBoundsException If the offset or count are out of bounds.
* @stable ICU 3.0
*/
public static String newString(int[] codePoints, int offset, int count) {
if (count < 0) {
throw new IllegalArgumentException();
}
char[] chars = new char[count];
int w = 0;
for (int r = offset, e = offset + count; r < e; ++r) {
int cp = codePoints[r];
if (cp < 0 || cp > 0x10ffff) {
throw new IllegalArgumentException();
}
while (true) {
try {
if (cp < 0x010000) {
chars[w] = (char) cp;
w++;
} else {
chars[w] = (char) (LEAD_SURROGATE_OFFSET_ + (cp >> LEAD_SURROGATE_SHIFT_));
chars[w + 1] = (char) (TRAIL_SURROGATE_MIN_VALUE + (cp & TRAIL_SURROGATE_MASK_));
w += 2;
}
break;
} catch (IndexOutOfBoundsException ex) {
int newlen = (int) (Math.ceil((double) codePoints.length * (w + 2)
/ (r - offset + 1)));
char[] temp = new char[newlen];
System.arraycopy(chars, 0, temp, 0, w);
chars = temp;
}
}
}
return new String(chars, 0, w);
}
/**
*
* UTF16 string comparator class. Allows UTF16 string comparison to be done with the various
* modes
*
*
* - Code point comparison or code unit comparison
*
- Case sensitive comparison, case insensitive comparison or case insensitive comparison
* with special handling for character 'i'.
*
*
* The code unit or code point comparison differ only when comparing supplementary code points
* (\u10000..\u10ffff) to BMP code points near the end of the BMP (i.e.,
* \ue000..\uffff). In code unit comparison, high BMP code points sort after
* supplementary code points because they are stored as pairs of surrogates which are at
* \ud800..\udfff.
*
*
* @see #FOLD_CASE_DEFAULT
* @see #FOLD_CASE_EXCLUDE_SPECIAL_I
* @stable ICU 2.1
*/
public static final class StringComparator implements java.util.Comparator {
// public constructor ------------------------------------------------
/**
* Default constructor that does code unit comparison and case sensitive comparison.
*
* @stable ICU 2.1
*/
public StringComparator() {
this(false, false, FOLD_CASE_DEFAULT);
}
/**
* Constructor that does comparison based on the argument options.
*
* @param codepointcompare Flag to indicate true for code point comparison or false for code unit
* comparison.
* @param ignorecase False for case sensitive comparison, true for case-insensitive comparison
* @param foldcaseoption FOLD_CASE_DEFAULT or FOLD_CASE_EXCLUDE_SPECIAL_I. This option is used only
* when ignorecase is set to true. If ignorecase is false, this option is
* ignored.
* @see #FOLD_CASE_DEFAULT
* @see #FOLD_CASE_EXCLUDE_SPECIAL_I
* @throws IllegalArgumentException If foldcaseoption is out of range
* @stable ICU 2.4
*/
public StringComparator(boolean codepointcompare, boolean ignorecase, int foldcaseoption) {
setCodePointCompare(codepointcompare);
m_ignoreCase_ = ignorecase;
if (foldcaseoption < FOLD_CASE_DEFAULT || foldcaseoption > FOLD_CASE_EXCLUDE_SPECIAL_I) {
throw new IllegalArgumentException("Invalid fold case option");
}
m_foldCase_ = foldcaseoption;
}
// public data member ------------------------------------------------
/**
* Option value for case folding comparison:
*
* Comparison is case insensitive, strings are folded using default mappings defined in
* Unicode data file CaseFolding.txt, before comparison.
*
* @stable ICU 2.4
*/
public static final int FOLD_CASE_DEFAULT = 0;
/**
* Option value for case folding:
* Use the modified set of mappings provided in CaseFolding.txt to handle dotted I
* and dotless i appropriately for Turkic languages (tr, az).
*
*
Comparison is case insensitive, strings are folded using modified mappings defined in
* Unicode data file CaseFolding.txt, before comparison.
*
* @stable ICU 2.4
* @see com.ibm.icu.lang.UCharacter#FOLD_CASE_EXCLUDE_SPECIAL_I
*/
public static final int FOLD_CASE_EXCLUDE_SPECIAL_I = 1;
// public methods ----------------------------------------------------
// public setters ----------------------------------------------------
/**
* Sets the comparison mode to code point compare if flag is true. Otherwise comparison mode
* is set to code unit compare
*
* @param flag True for code point compare, false for code unit compare
* @stable ICU 2.4
*/
public void setCodePointCompare(boolean flag) {
if (flag) {
m_codePointCompare_ = Normalizer.COMPARE_CODE_POINT_ORDER;
} else {
m_codePointCompare_ = 0;
}
}
/**
* Sets the Comparator to case-insensitive comparison mode if argument is true, otherwise
* case sensitive comparison mode if set to false.
*
* @param ignorecase True for case-insensitive comparison, false for case sensitive comparison
* @param foldcaseoption FOLD_CASE_DEFAULT or FOLD_CASE_EXCLUDE_SPECIAL_I. This option is used only
* when ignorecase is set to true. If ignorecase is false, this option is
* ignored.
* @see #FOLD_CASE_DEFAULT
* @see #FOLD_CASE_EXCLUDE_SPECIAL_I
* @stable ICU 2.4
*/
public void setIgnoreCase(boolean ignorecase, int foldcaseoption) {
m_ignoreCase_ = ignorecase;
if (foldcaseoption < FOLD_CASE_DEFAULT || foldcaseoption > FOLD_CASE_EXCLUDE_SPECIAL_I) {
throw new IllegalArgumentException("Invalid fold case option");
}
m_foldCase_ = foldcaseoption;
}
// public getters ----------------------------------------------------
/**
* Checks if the comparison mode is code point compare.
*
* @return true for code point compare, false for code unit compare
* @stable ICU 2.4
*/
public boolean getCodePointCompare() {
return m_codePointCompare_ == Normalizer.COMPARE_CODE_POINT_ORDER;
}
/**
* Checks if Comparator is in the case insensitive mode.
*
* @return true if Comparator performs case insensitive comparison, false otherwise
* @stable ICU 2.4
*/
public boolean getIgnoreCase() {
return m_ignoreCase_;
}
/**
* Gets the fold case options set in Comparator to be used with case insensitive comparison.
*
* @return either FOLD_CASE_DEFAULT or FOLD_CASE_EXCLUDE_SPECIAL_I
* @see #FOLD_CASE_DEFAULT
* @see #FOLD_CASE_EXCLUDE_SPECIAL_I
* @stable ICU 2.4
*/
public int getIgnoreCaseOption() {
return m_foldCase_;
}
// public other methods ----------------------------------------------
/**
* Compare two strings depending on the options selected during construction.
*
* @param a first source string.
* @param b second source string.
* @return 0 returned if a == b. If a < b, a negative value is returned. Otherwise if a > b,
* a positive value is returned.
* @exception ClassCastException thrown when either a or b is not a String object
* @stable ICU 4.4
*/
@Override
public int compare(String a, String b) {
if (Utility.sameObjects(a, b)) {
return 0;
}
if (a == null) {
return -1;
}
if (b == null) {
return 1;
}
if (m_ignoreCase_) {
return compareCaseInsensitive(a, b);
}
return compareCaseSensitive(a, b);
}
// private data member ----------------------------------------------
/**
* Code unit comparison flag. True if code unit comparison is required. False if code point
* comparison is required.
*/
private int m_codePointCompare_;
/**
* Fold case comparison option.
*/
private int m_foldCase_;
/**
* Flag indicator if ignore case is to be used during comparison
*/
private boolean m_ignoreCase_;
/**
* Code point order offset for surrogate characters
*/
private static final int CODE_POINT_COMPARE_SURROGATE_OFFSET_ = 0x2800;
// private method ---------------------------------------------------
/**
* Compares case insensitive. This is a direct port of ICU4C, to make maintenance life
* easier.
*
* @param s1
* first string to compare
* @param s2
* second string to compare
* @return -1 is s1 < s2, 0 if equals,
*/
private int compareCaseInsensitive(String s1, String s2) {
return Normalizer.cmpEquivFold(s1, s2, m_foldCase_ | m_codePointCompare_
| Normalizer.COMPARE_IGNORE_CASE);
}
/**
* Compares case sensitive. This is a direct port of ICU4C, to make maintenance life
* easier.
*
* @param s1
* first string to compare
* @param s2
* second string to compare
* @return -1 is s1 < s2, 0 if equals,
*/
private int compareCaseSensitive(String s1, String s2) {
// compare identical prefixes - they do not need to be fixed up
// limit1 = start1 + min(length1, length2)
int length1 = s1.length();
int length2 = s2.length();
int minlength = length1;
int result = 0;
if (length1 < length2) {
result = -1;
} else if (length1 > length2) {
result = 1;
minlength = length2;
}
char c1 = 0;
char c2 = 0;
int index = 0;
for (; index < minlength; index++) {
c1 = s1.charAt(index);
c2 = s2.charAt(index);
// check pseudo-limit
if (c1 != c2) {
break;
}
}
if (index == minlength) {
return result;
}
boolean codepointcompare = m_codePointCompare_ == Normalizer.COMPARE_CODE_POINT_ORDER;
// if both values are in or above the surrogate range, fix them up
if (c1 >= LEAD_SURROGATE_MIN_VALUE && c2 >= LEAD_SURROGATE_MIN_VALUE
&& codepointcompare) {
// subtract 0x2800 from BMP code points to make them smaller
// than supplementary ones
if ((c1 <= LEAD_SURROGATE_MAX_VALUE && (index + 1) != length1 && isTrailSurrogate(s1.charAt(index + 1)))
|| (isTrailSurrogate(c1) && index != 0 && isLeadSurrogate(s1.charAt(index - 1)))) {
// part of a surrogate pair, leave >=d800
} else {
// BMP code point - may be surrogate code point - make
// < d800
c1 -= CODE_POINT_COMPARE_SURROGATE_OFFSET_;
}
if ((c2 <= LEAD_SURROGATE_MAX_VALUE && (index + 1) != length2 && isTrailSurrogate(s2.charAt(index + 1)))
|| (isTrailSurrogate(c2) && index != 0 && isLeadSurrogate(s2.charAt(index - 1)))) {
// part of a surrogate pair, leave >=d800
} else {
// BMP code point - may be surrogate code point - make 2) {
return -1;
}
// at this point, len = 2
int cp = Character.codePointAt(s, 0);
if (cp > 0xFFFF) { // is surrogate pair
return cp;
}
return -1;
}
/**
* Utility for comparing a code point to a string without having to create a new string. Returns the same results
* as a code point comparison of UTF16.valueOf(codePoint) and s.toString(). More specifically, if
*
* sc = new StringComparator(true,false,0);
* fast = UTF16.compareCodePoint(codePoint, charSequence)
* slower = sc.compare(UTF16.valueOf(codePoint), charSequence == null ? "" : charSequence.toString())
*
* then
*
* Integer.signum(fast) == Integer.signum(slower)
*
* @param codePoint to test
* @param s to test
* @return equivalent of code point comparator comparing two strings.
* @stable ICU 54
*/
public static int compareCodePoint(int codePoint, CharSequence s) {
if (s == null) {
return 1;
}
final int strLen = s.length();
if (strLen == 0) {
return 1;
}
int second = Character.codePointAt(s, 0);
int diff = codePoint - second;
if (diff != 0) {
return diff;
}
return strLen == Character.charCount(codePoint) ? 0 : -1;
}
// private data members -------------------------------------------------
/**
* Shift value for lead surrogate to form a supplementary character.
*/
private static final int LEAD_SURROGATE_SHIFT_ = 10;
/**
* Mask to retrieve the significant value from a trail surrogate.
*/
private static final int TRAIL_SURROGATE_MASK_ = 0x3FF;
/**
* Value that all lead surrogate starts with
*/
private static final int LEAD_SURROGATE_OFFSET_ = LEAD_SURROGATE_MIN_VALUE
- (SUPPLEMENTARY_MIN_VALUE >> LEAD_SURROGATE_SHIFT_);
// private methods ------------------------------------------------------
/**
*
* Converts argument code point and returns a String object representing the code point's value
* in UTF16 format.
*
*
* This method does not check for the validity of the codepoint, the results are not guaranteed
* if a invalid codepoint is passed as argument.
*
*
* The result is a string whose length is 1 for non-supplementary code points, 2 otherwise.
*
*
* @param ch
* code point
* @return string representation of the code point
*/
private static String toString(int ch) {
if (ch < SUPPLEMENTARY_MIN_VALUE) {
return String.valueOf((char) ch);
}
StringBuilder result = new StringBuilder();
result.append(getLeadSurrogate(ch));
result.append(getTrailSurrogate(ch));
return result.toString();
}
}
// eof