Class UTF16
- java.lang.Object
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- com.adobe.agl.text.UTF16
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public final class UTF16 extends java.lang.Object
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
Examples:bounds()
.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
andTrail
in the API, which gives a better sense of their ordering in a string.offset16
andoffset32
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 tochar16
, 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.
- Naming: For clarity, High and Low surrogates are called
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Field Summary
Fields Modifier and Type Field Description static int
CODEPOINT_MAX_VALUE
The highest Unicode code point value (scalar value) according to the Unicode Standard.static int
CODEPOINT_MIN_VALUE
The lowest Unicode code point value.static int
LEAD_SURROGATE_BOUNDARY
Value returned inbounds()
.static int
LEAD_SURROGATE_MAX_VALUE
Lead surrogate maximum valuestatic int
LEAD_SURROGATE_MIN_VALUE
Lead surrogate minimum valuestatic int
SINGLE_CHAR_BOUNDARY
Value returned inbounds()
.static int
SUPPLEMENTARY_MIN_VALUE
The minimum value for Supplementary code pointsstatic int
SURROGATE_MAX_VALUE
Maximum surrogate valuestatic int
SURROGATE_MIN_VALUE
Surrogate minimum valuestatic int
TRAIL_SURROGATE_BOUNDARY
Value returned inbounds()
.static int
TRAIL_SURROGATE_MAX_VALUE
Trail surrogate maximum valuestatic int
TRAIL_SURROGATE_MIN_VALUE
Trail surrogate minimum value
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Method Summary
All Methods Static Methods Concrete Methods Modifier and Type Method Description static int
append(char[] target, int limit, int char32)
Adds a codepoint to offset16 position of the argument char array.static java.lang.StringBuffer
append(java.lang.StringBuffer target, int char32)
Append a single UTF-32 value to the end of a StringBuffer.static java.lang.StringBuffer
appendCodePoint(java.lang.StringBuffer target, int cp)
Cover JDK 1.5 APIs.static int
bounds(char[] source, int start, int limit, int offset16)
Returns the type of the boundaries around the char at offset16.static int
bounds(java.lang.StringBuffer source, int offset16)
Returns the type of the boundaries around the char at offset16.static int
bounds(java.lang.String source, int offset16)
Returns the type of the boundaries around the char at offset16.static int
charAt(char[] source, int start, int limit, int offset16)
Extract a single UTF-32 value from a substring.static int
charAt(Replaceable source, int offset16)
Extract a single UTF-32 value from a string.static int
charAt(java.lang.CharSequence source, int offset16)
Extract a single UTF-32 value from a string.static int
charAt(java.lang.StringBuffer source, int offset16)
Extract a single UTF-32 value from a string.static int
charAt(java.lang.String source, int offset16)
Extract a single UTF-32 value from a string.static int
countCodePoint(char[] source, int start, int limit)
Number of codepoints in a UTF16 char array substringstatic int
countCodePoint(java.lang.String source)
Number of codepoints in a UTF16 Stringstatic int
countCodePoint(java.lang.StringBuffer source)
Number of codepoints in a UTF16 String bufferstatic int
delete(char[] target, int limit, int offset16)
Removes the codepoint at the specified position in this target (shortening target by 1 character if the codepoint is a non-supplementary, 2 otherwise).static java.lang.StringBuffer
delete(java.lang.StringBuffer target, int offset16)
Removes the codepoint at the specified position in this target (shortening target by 1 character if the codepoint is a non-supplementary, 2 otherwise).static int
findCodePointOffset(char[] source, int start, int limit, int offset16)
Returns the UTF-32 offset corresponding to the first UTF-32 boundary at the given UTF-16 offset.static int
findCodePointOffset(java.lang.StringBuffer source, int offset16)
Returns the UTF-32 offset corresponding to the first UTF-32 boundary at the given UTF-16 offset.static int
findCodePointOffset(java.lang.String source, int offset16)
Returns the UTF-32 offset corresponding to the first UTF-32 boundary at or after the given UTF-16 offset.static int
findOffsetFromCodePoint(char[] source, int start, int limit, int offset32)
Returns the UTF-16 offset that corresponds to a UTF-32 offset.static int
findOffsetFromCodePoint(java.lang.StringBuffer source, int offset32)
Returns the UTF-16 offset that corresponds to a UTF-32 offset.static int
findOffsetFromCodePoint(java.lang.String source, int offset32)
Returns the UTF-16 offset that corresponds to a UTF-32 offset.static int
getCharCount(int char32)
Determines how many chars this char32 requires.static char
getLeadSurrogate(int char32)
Returns the lead surrogate.static char
getTrailSurrogate(int char32)
Returns the trail surrogate.static boolean
hasMoreCodePointsThan(char[] source, int start, int limit, int number)
Check if the sub-range of char array, from argument start to limit, contains more Unicode code points than a certain number.static boolean
hasMoreCodePointsThan(java.lang.StringBuffer source, int number)
Check if the string buffer contains more Unicode code points than a certain number.static boolean
hasMoreCodePointsThan(java.lang.String source, int number)
Check if the string contains more Unicode code points than a certain number.static int
indexOf(java.lang.String source, int char32)
Returns the index within the argument UTF16 format Unicode string of the first occurrence of the argument codepoint.static int
indexOf(java.lang.String source, int char32, int fromIndex)
Returns the index within the argument UTF16 format Unicode string of the first occurrence of the argument codepoint.static int
indexOf(java.lang.String source, java.lang.String str)
Returns the index within the argument UTF16 format Unicode string of the first occurrence of the argument string str.static int
indexOf(java.lang.String source, java.lang.String str, int fromIndex)
Returns the index within the argument UTF16 format Unicode string of the first occurrence of the argument string str.static int
insert(char[] target, int limit, int offset16, int char32)
Inserts char32 codepoint into target at the argument offset16.static java.lang.StringBuffer
insert(java.lang.StringBuffer target, int offset16, int char32)
Inserts char32 codepoint into target at the argument offset16.static boolean
isLeadSurrogate(char char16)
Determines whether the character is a lead surrogate.static boolean
isSurrogate(char char16)
Determines whether the code value is a surrogate.static boolean
isTrailSurrogate(char char16)
Determines whether the character is a trail surrogate.static int
lastIndexOf(java.lang.String source, int char32)
Returns the index within the argument UTF16 format Unicode string of the last occurrence of the argument codepoint.static int
lastIndexOf(java.lang.String source, int char32, int fromIndex)
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.static int
lastIndexOf(java.lang.String source, java.lang.String str)
Returns the index within the argument UTF16 format Unicode string of the last occurrence of the argument string str.static int
lastIndexOf(java.lang.String source, java.lang.String str, int 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.static int
moveCodePointOffset(char[] source, int start, int limit, int offset16, int shift32)
Shifts offset16 by the argument number of codepoints within a subarray.static int
moveCodePointOffset(java.lang.StringBuffer source, int offset16, int shift32)
Shifts offset16 by the argument number of codepointsstatic int
moveCodePointOffset(java.lang.String source, int offset16, int shift32)
Shifts offset16 by the argument number of codepointsstatic java.lang.String
newString(int[] codePoints, int offset, int count)
Cover JDK 1.5 API.static java.lang.String
replace(java.lang.String source, int oldChar32, int newChar32)
Returns a new UTF16 format Unicode string resulting from replacing all occurrences of oldChar32 in source with newChar32.static java.lang.String
replace(java.lang.String source, java.lang.String oldStr, java.lang.String newStr)
Returns a new UTF16 format Unicode string resulting from replacing all occurrences of oldStr in source with newStr.static java.lang.StringBuffer
reverse(java.lang.StringBuffer source)
Reverses a UTF16 format Unicode string and replaces source's content with it.static int
setCharAt(char[] target, int limit, int offset16, int char32)
Set a code point into a UTF16 position in a char array.static void
setCharAt(java.lang.StringBuffer target, int offset16, int char32)
Set a code point into a UTF16 position.static java.lang.String
valueOf(char[] source, int start, int limit, int offset16)
Convenience method.static java.lang.String
valueOf(int char32)
Convenience method corresponding to String.valueOf(char).static java.lang.String
valueOf(java.lang.StringBuffer source, int offset16)
Convenience method corresponding to StringBuffer.valueOf(codepoint at offset16).static java.lang.String
valueOf(java.lang.String source, int offset16)
Convenience method corresponding to String.valueOf(codepoint at offset16).
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Field Detail
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SINGLE_CHAR_BOUNDARY
public static final int SINGLE_CHAR_BOUNDARY
Value returned inbounds()
. These values are chosen specifically so that it actually represents the position of the character [offset16 - (value >> 2), offset16 + (value & 3)]- See Also:
- Constant Field Values
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LEAD_SURROGATE_BOUNDARY
public static final int LEAD_SURROGATE_BOUNDARY
Value returned inbounds()
. These values are chosen specifically so that it actually represents the position of the character [offset16 - (value >> 2), offset16 + (value & 3)]- See Also:
- Constant Field Values
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TRAIL_SURROGATE_BOUNDARY
public static final int TRAIL_SURROGATE_BOUNDARY
Value returned inbounds()
. These values are chosen specifically so that it actually represents the position of the character [offset16 - (value >> 2), offset16 + (value & 3)]- See Also:
- Constant Field Values
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CODEPOINT_MIN_VALUE
public static final int CODEPOINT_MIN_VALUE
The lowest Unicode code point value.- See Also:
- Constant Field Values
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CODEPOINT_MAX_VALUE
public static final int CODEPOINT_MAX_VALUE
The highest Unicode code point value (scalar value) according to the Unicode Standard.- See Also:
- Constant Field Values
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SUPPLEMENTARY_MIN_VALUE
public static final int SUPPLEMENTARY_MIN_VALUE
The minimum value for Supplementary code points- See Also:
- Constant Field Values
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LEAD_SURROGATE_MIN_VALUE
public static final int LEAD_SURROGATE_MIN_VALUE
Lead surrogate minimum value- See Also:
- Constant Field Values
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TRAIL_SURROGATE_MIN_VALUE
public static final int TRAIL_SURROGATE_MIN_VALUE
Trail surrogate minimum value- See Also:
- Constant Field Values
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LEAD_SURROGATE_MAX_VALUE
public static final int LEAD_SURROGATE_MAX_VALUE
Lead surrogate maximum value- See Also:
- Constant Field Values
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TRAIL_SURROGATE_MAX_VALUE
public static final int TRAIL_SURROGATE_MAX_VALUE
Trail surrogate maximum value- See Also:
- Constant Field Values
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SURROGATE_MIN_VALUE
public static final int SURROGATE_MIN_VALUE
Surrogate minimum value- See Also:
- Constant Field Values
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SURROGATE_MAX_VALUE
public static final int SURROGATE_MAX_VALUE
Maximum surrogate value- See Also:
- Constant Field Values
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Method Detail
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charAt
public static int charAt(java.lang.String source, int offset16)
Extract a single UTF-32 value from a string. Used when iterating forwards or backwards (withUTF16.getCharCount()
, as well as random access. If a validity check is required, useUCharacter.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- Parameters:
source
- array of UTF-16 charsoffset16
- UTF-16 offset to the start of the character.- Returns:
- 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()
. - Throws:
java.lang.IndexOutOfBoundsException
- thrown if offset16 is out of bounds.
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charAt
public static int charAt(java.lang.CharSequence source, int offset16)
Extract a single UTF-32 value from a string. Used when iterating forwards or backwards (withUTF16.getCharCount()
, as well as random access. If a validity check is required, useUCharacter.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- Parameters:
source
- array of UTF-16 charsoffset16
- UTF-16 offset to the start of the character.- Returns:
- 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()
. - Throws:
java.lang.IndexOutOfBoundsException
- thrown if offset16 is out of bounds.
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charAt
public static int charAt(java.lang.StringBuffer source, int offset16)
Extract a single UTF-32 value from a string. Used when iterating forwards or backwards (withUTF16.getCharCount()
, as well as random access. If a validity check is required, useUCharacter.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- Parameters:
source
- UTF-16 chars string bufferoffset16
- UTF-16 offset to the start of the character.- Returns:
- 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()
. - Throws:
java.lang.IndexOutOfBoundsException
- thrown if offset16 is out of bounds.
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charAt
public static int charAt(char[] source, int start, int limit, int offset16)
Extract a single UTF-32 value from a substring. Used when iterating forwards or backwards (withUTF16.getCharCount()
, as well as random access. If a validity check is required, useUCharacter.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- Parameters:
source
- array of UTF-16 charsstart
- offset to substring in the source array for analyzinglimit
- offset to substring in the source array for analyzingoffset16
- UTF-16 offset relative to start- Returns:
- 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()
. - Throws:
java.lang.IndexOutOfBoundsException
- thrown if offset16 is not within the range of start and limit.
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charAt
public static int charAt(Replaceable source, int offset16)
Extract a single UTF-32 value from a string. Used when iterating forwards or backwards (withUTF16.getCharCount()
, as well as random access. If a validity check is required, useUCharacter.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- Parameters:
source
- UTF-16 chars string bufferoffset16
- UTF-16 offset to the start of the character.- Returns:
- 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()
. - Throws:
java.lang.IndexOutOfBoundsException
- thrown if offset16 is out of bounds.
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getCharCount
public static int getCharCount(int char32)
Determines how many chars this char32 requires. If a validity check is required, useisLegal()
on char32 before calling.- Parameters:
char32
- the input codepoint.- Returns:
- 2 if is in supplementary space, otherwise 1.
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bounds
public static int bounds(java.lang.String source, int offset16)
Returns the type of the boundaries around the char at offset16. Used for random access.- Parameters:
source
- text to analyseoffset16
- UTF-16 offset- Returns:
- 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]
- Throws:
java.lang.IndexOutOfBoundsException
- if offset16 is out of bounds.
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bounds
public static int bounds(java.lang.StringBuffer source, int offset16)
Returns the type of the boundaries around the char at offset16. Used for random access.- Parameters:
source
- string buffer to analyseoffset16
- UTF16 offset- Returns:
- 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]
- Throws:
java.lang.IndexOutOfBoundsException
- if offset16 is out of bounds.
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bounds
public static int bounds(char[] source, int start, int limit, int offset16)
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.- Parameters:
source
- char array to analysestart
- offset to substring in the source array for analyzinglimit
- offset to substring in the source array for analyzingoffset16
- UTF16 offset relative to start- Returns:
- 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]
- Throws:
java.lang.IndexOutOfBoundsException
- if offset16 is not within the range of start and limit.
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isSurrogate
public static boolean isSurrogate(char char16)
Determines whether the code value is a surrogate.- Parameters:
char16
- the input character.- Returns:
- true iff the input character is a surrogate.
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isTrailSurrogate
public static boolean isTrailSurrogate(char char16)
Determines whether the character is a trail surrogate.- Parameters:
char16
- the input character.- Returns:
- true iff the input character is a trail surrogate.
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isLeadSurrogate
public static boolean isLeadSurrogate(char char16)
Determines whether the character is a lead surrogate.- Parameters:
char16
- the input character.- Returns:
- true iff the input character is a lead surrogate
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getLeadSurrogate
public static char getLeadSurrogate(int char32)
Returns the lead surrogate. If a validity check is required, useisLegal()
on char32 before calling.- Parameters:
char32
- the input character.- Returns:
- lead surrogate if the getCharCount(ch) is 2;
and 0 otherwise (note: 0 is not a valid lead surrogate).
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getTrailSurrogate
public static char getTrailSurrogate(int char32)
Returns the trail surrogate. If a validity check is required, useisLegal()
on char32 before calling.- Parameters:
char32
- the input character.- Returns:
- the trail surrogate if the getCharCount(ch) is 2;
otherwise the character itself
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valueOf
public static java.lang.String valueOf(int 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 isLegal() on char32 before calling.- Parameters:
char32
- the input character.- Returns:
- string value of char32 in UTF16 format
- Throws:
java.lang.IllegalArgumentException
- thrown if char32 is a invalid codepoint.
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valueOf
public static java.lang.String valueOf(java.lang.String source, int offset16)
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 isLegal() 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.- Parameters:
source
- the input string.offset16
- the UTF16 index to the codepoint in source- Returns:
- string value of char32 in UTF16 format
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valueOf
public static java.lang.String valueOf(java.lang.StringBuffer source, int offset16)
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 isLegal() 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.- Parameters:
source
- the input string buffer.offset16
- the UTF16 index to the codepoint in source- Returns:
- string value of char32 in UTF16 format
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valueOf
public static java.lang.String valueOf(char[] source, int start, int limit, int offset16)
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 isLegal() on the codepoint at offset16 before calling. The result returned will be a newly created String containing the relevant characters.- Parameters:
source
- the input char array.start
- start index of the subarraylimit
- end index of the subarrayoffset16
- the UTF16 index to the codepoint in source relative to start- Returns:
- string value of char32 in UTF16 format
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findOffsetFromCodePoint
public static int findOffsetFromCodePoint(java.lang.String source, int offset32)
Returns the UTF-16 offset that corresponds to a UTF-32 offset. Used for random access. See the class description for notes on roundtripping.- Parameters:
source
- the UTF-16 stringoffset32
- UTF-32 offset- Returns:
- UTF-16 offset
- Throws:
java.lang.IndexOutOfBoundsException
- if offset32 is out of bounds.
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findOffsetFromCodePoint
public static int findOffsetFromCodePoint(java.lang.StringBuffer source, int offset32)
Returns the UTF-16 offset that corresponds to a UTF-32 offset. Used for random access. See the class description for notes on roundtripping.- Parameters:
source
- the UTF-16 string bufferoffset32
- UTF-32 offset- Returns:
- UTF-16 offset
- Throws:
java.lang.IndexOutOfBoundsException
- if offset32 is out of bounds.
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findOffsetFromCodePoint
public static int findOffsetFromCodePoint(char[] source, int start, int limit, int offset32)
Returns the UTF-16 offset that corresponds to a UTF-32 offset. Used for random access. See the class description for notes on roundtripping.- Parameters:
source
- the UTF-16 char array whose substring is to be analysedstart
- offset of the substring to be analysedlimit
- offset of the substring to be analysedoffset32
- UTF-32 offset relative to start- Returns:
- UTF-16 offset relative to start
- Throws:
java.lang.IndexOutOfBoundsException
- if offset32 is out of bounds.
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findCodePointOffset
public static int findCodePointOffset(java.lang.String source, int offset16)
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 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());
- Parameters:
source
- text to analyseoffset16
- UTF-16 offset < source text length.- Returns:
- UTF-32 offset
- Throws:
java.lang.IndexOutOfBoundsException
- if offset16 is out of bounds.
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findCodePointOffset
public static int findCodePointOffset(java.lang.StringBuffer source, int offset16)
Returns the UTF-32 offset corresponding to the first UTF-32 boundary at the given UTF-16 offset. Used for random access. See the 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);
- Parameters:
source
- text to analyseoffset16
- UTF-16 offset < source text length.- Returns:
- UTF-32 offset
- Throws:
java.lang.IndexOutOfBoundsException
- if offset16 is out of bounds.
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findCodePointOffset
public static int findCodePointOffset(char[] source, int start, int limit, int offset16)
Returns the UTF-32 offset corresponding to the first UTF-32 boundary at the given UTF-16 offset. Used for random access. See the 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);
- Parameters:
source
- text to analysestart
- offset of the substringlimit
- offset of the substringoffset16
- UTF-16 relative to start- Returns:
- UTF-32 offset relative to start
- Throws:
java.lang.IndexOutOfBoundsException
- if offset16 is not within the range of start and limit.
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append
public static java.lang.StringBuffer append(java.lang.StringBuffer target, int char32)
Append a single UTF-32 value to the end of a StringBuffer. If a validity check is required, use isLegal() on char32 before calling.- Parameters:
target
- the buffer to append tochar32
- value to append.- Returns:
- the updated StringBuffer
- Throws:
java.lang.IllegalArgumentException
- thrown when char32 does not lie within the range of the Unicode codepoints
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appendCodePoint
public static java.lang.StringBuffer appendCodePoint(java.lang.StringBuffer target, int cp)
Cover JDK 1.5 APIs. Append the code point to the buffer and return the buffer as a convenience.- Parameters:
target
- the buffer to append tocp
- the code point to append- Returns:
- the updated StringBuffer
- Throws:
java.lang.IllegalArgumentException
- if cp is not a valid code point
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append
public static int append(char[] target, int limit, int char32)
Adds a codepoint to offset16 position of the argument char array.- Parameters:
target
- char array to be append with the new code pointlimit
- UTF16 offset which the codepoint will be appended.char32
- code point to be appended- Returns:
- offset after char32 in the array.
- Throws:
java.lang.IllegalArgumentException
- thrown if there is not enough space for the append, or when char32 does not lie within the range of the Unicode codepoints.
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countCodePoint
public static int countCodePoint(java.lang.String source)
Number of codepoints in a UTF16 String- Parameters:
source
- UTF16 string- Returns:
- number of codepoint in string
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countCodePoint
public static int countCodePoint(java.lang.StringBuffer source)
Number of codepoints in a UTF16 String buffer- Parameters:
source
- UTF16 string buffer- Returns:
- number of codepoint in string
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countCodePoint
public static int countCodePoint(char[] source, int start, int limit)
Number of codepoints in a UTF16 char array substring- Parameters:
source
- UTF16 char arraystart
- offset of the substringlimit
- offset of the substring- Returns:
- number of codepoint in the substring
- Throws:
java.lang.IndexOutOfBoundsException
- if start and limit are not valid.
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setCharAt
public static void setCharAt(java.lang.StringBuffer target, int offset16, int char32)
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.- Parameters:
target
- stringbufferoffset16
- UTF16 position to insert intochar32
- code point
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setCharAt
public static int setCharAt(char[] target, int limit, int offset16, int 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.- Parameters:
target
- char arraylimit
- 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.offset16
- UTF16 position to insert intochar32
- code point- Returns:
- new number of chars in target that represents a string
- Throws:
java.lang.IndexOutOfBoundsException
- if offset16 is out of range
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moveCodePointOffset
public static int moveCodePointOffset(java.lang.String source, int offset16, int shift32)
Shifts offset16 by the argument number of codepoints- Parameters:
source
- stringoffset16
- UTF16 position to shiftshift32
- number of codepoints to shift- Returns:
- new shifted offset16
- Throws:
java.lang.IndexOutOfBoundsException
- if the new offset16 is out of bounds.
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moveCodePointOffset
public static int moveCodePointOffset(java.lang.StringBuffer source, int offset16, int shift32)
Shifts offset16 by the argument number of codepoints- Parameters:
source
- string bufferoffset16
- UTF16 position to shiftshift32
- number of codepoints to shift- Returns:
- new shifted offset16
- Throws:
java.lang.IndexOutOfBoundsException
- if the new offset16 is out of bounds.
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moveCodePointOffset
public static int moveCodePointOffset(char[] source, int start, int limit, int offset16, int shift32)
Shifts offset16 by the argument number of codepoints within a subarray.- Parameters:
source
- char arraystart
- position of the subarray to be performed onlimit
- position of the subarray to be performed onoffset16
- UTF16 position to shift relative to startshift32
- number of codepoints to shift- Returns:
- new shifted offset16 relative to start
- Throws:
java.lang.IndexOutOfBoundsException
- if the new offset16 is out of bounds with respect to the subarray or the subarray bounds are out of range.
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insert
public static java.lang.StringBuffer insert(java.lang.StringBuffer target, int offset16, int char32)
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.
- Parameters:
target
- string buffer to insert tooffset16
- offset which char32 will be inserted inchar32
- codepoint to be inserted- Returns:
- a reference to target
- Throws:
java.lang.IndexOutOfBoundsException
- thrown if offset16 is invalid.
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insert
public static int insert(char[] target, int limit, int offset16, int char32)
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.
- Parameters:
target
- char array to insert tolimit
- end index of the char array, limit <= target.lengthoffset16
- offset which char32 will be inserted inchar32
- codepoint to be inserted- Returns:
- new limit size
- Throws:
java.lang.IndexOutOfBoundsException
- thrown if offset16 is invalid.
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delete
public static java.lang.StringBuffer delete(java.lang.StringBuffer target, int offset16)
Removes the codepoint at the specified position in this target (shortening target by 1 character if the codepoint is a non-supplementary, 2 otherwise).- Parameters:
target
- string buffer to remove codepoint fromoffset16
- offset which the codepoint will be removed- Returns:
- a reference to target
- Throws:
java.lang.IndexOutOfBoundsException
- thrown if offset16 is invalid.
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delete
public static int delete(char[] target, int limit, int offset16)
Removes the codepoint at the specified position in this target (shortening target by 1 character if the codepoint is a non-supplementary, 2 otherwise).- Parameters:
target
- string buffer to remove codepoint fromlimit
- end index of the char array, limit <= target.lengthoffset16
- offset which the codepoint will be removed- Returns:
- a new limit size
- Throws:
java.lang.IndexOutOfBoundsException
- thrown if offset16 is invalid.
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indexOf
public static int indexOf(java.lang.String source, int char32)
Returns the index within the argument UTF16 format Unicode string of the first occurrence of the argument codepoint. I.e., the smallest indexi
such thatUTF16.charAt(source, i) == char32
is true.If no such character occurs in this string, then -1 is returned.
Examples:
Note this method is provided as support to jdk 1.3, which does not support supplementary characters to its fullest.
UTF16.indexOf("abc", 'a') returns 0
UTF16.indexOf("abc𐀀", 0x10000) returns 3
UTF16.indexOf("abc𐀀", 0xd800) returns -1
- Parameters:
source
- UTF16 format Unicode string that will be searchedchar32
- codepoint to search for- Returns:
- the index of the first occurrence of the codepoint in the argument Unicode string, or -1 if the codepoint does not occur.
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indexOf
public static int indexOf(java.lang.String source, java.lang.String str)
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:
Note this method is provided as support to jdk 1.3, which does not support supplementary characters to its fullest.
UTF16.indexOf("abc", "ab") returns 0
UTF16.indexOf("abc𐀀", "𐀀") returns 3
UTF16.indexOf("abc𐀀", "?") returns -1
- Parameters:
source
- UTF16 format Unicode string that will be searchedstr
- UTF16 format Unicode string to search for- Returns:
- the index of the first occurrence of the codepoint in the argument Unicode string, or -1 if the codepoint does not occur.
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indexOf
public static int indexOf(java.lang.String source, int char32, int fromIndex)
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:
Note this method is provided as support to jdk 1.3, which does not support supplementary characters to its fullest.
UTF16.indexOf("abc", 'a', 1) returns -1
UTF16.indexOf("abc𐀀", 0x10000, 1) returns 3
UTF16.indexOf("abc𐀀", 0xd800, 1) returns -1
- Parameters:
source
- UTF16 format Unicode string that will be searchedchar32
- codepoint to search forfromIndex
- the index to start the search from.- Returns:
- 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.
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indexOf
public static int indexOf(java.lang.String source, java.lang.String str, int 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:
Note this method is provided as support to jdk 1.3, which does not support supplementary characters to its fullest.
UTF16.indexOf("abc", "ab", 0) returns 0
UTF16.indexOf("abc𐀀", "𐀀", 0) returns 3
UTF16.indexOf("abc𐀀", "𐀀", 2) returns 3
UTF16.indexOf("abc𐀀", "?", 0) returns -1
- Parameters:
source
- UTF16 format Unicode string that will be searchedstr
- UTF16 format Unicode string to search forfromIndex
- the index to start the search from.- Returns:
- the index of the first occurrence of the codepoint in the argument Unicode string, or -1 if the codepoint does not occur.
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lastIndexOf
public static int lastIndexOf(java.lang.String source, int char32)
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("abc𐀀", 0x10000) returns 3
UTF16.lastIndexOf("abc𐀀", 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.- Parameters:
source
- UTF16 format Unicode string that will be searchedchar32
- codepoint to search for- Returns:
- the index of the last occurrence of the codepoint in source, or -1 if the codepoint does not occur.
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lastIndexOf
public static int lastIndexOf(java.lang.String source, java.lang.String str)
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("abc𐀀", "𐀀") returns 3
UTF16.lastIndexOf("abc𐀀", "?") 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.- Parameters:
source
- UTF16 format Unicode string that will be searchedstr
- UTF16 format Unicode string to search for- Returns:
- the index of the last occurrence of the codepoint in source, or -1 if the codepoint does not occur.
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lastIndexOf
public static int lastIndexOf(java.lang.String source, int char32, int fromIndex)
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:
Note this method is provided as support to jdk 1.3, which does not support supplementary characters to its fullest.
UTF16.lastIndexOf("abc", 'c', 2) returns 2
UTF16.lastIndexOf("abc", 'c', 1) returns -1
UTF16.lastIndexOf("abc𐀀", 0x10000, 5) returns 3
UTF16.lastIndexOf("abc𐀀", 0x10000, 3) returns 3
UTF16.lastIndexOf("abc𐀀", 0xd800) returns -1
- Parameters:
source
- UTF16 format Unicode string that will be searchedchar32
- codepoint to search forfromIndex
- 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.- Returns:
- the index of the last occurrence of the codepoint in source, or -1 if the codepoint does not occur.
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lastIndexOf
public static int lastIndexOf(java.lang.String source, java.lang.String str, int 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("abc𐀀", "𐀀", 5) returns 3
UTF16.lastIndexOf("abc𐀀", "𐀀", 3) returns 3
UTF16.lastIndexOf("abc𐀀", "?", 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.- Parameters:
source
- UTF16 format Unicode string that will be searchedstr
- UTF16 format Unicode string to search forfromIndex
- 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.- Returns:
- the index of the last occurrence of the codepoint in source, or -1 if the codepoint does not occur.
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replace
public static java.lang.String replace(java.lang.String source, int oldChar32, int newChar32)
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:
Note this method is provided as support to jdk 1.3, which does not support supplementary characters to its fullest.
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 𐀀", 0x10000, '!');
returns "Supplementary character !"
UTF16.replace("Supplementary character 𐀀", 0xd800, '!');
returns "Supplementary character 𐀀"
- Parameters:
source
- UTF16 format Unicode string which the codepoint replacements will be based on.oldChar32
- non-zero old codepoint to be replaced.newChar32
- the new codepoint to replace oldChar32- Returns:
- 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.
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replace
public static java.lang.String replace(java.lang.String source, java.lang.String oldStr, java.lang.String newStr)
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:
Note this method is provided as support to jdk 1.3, which does not support supplementary characters to its fullest.
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 𐀀", "𐀀", '!');
returns "Supplementary character !"
UTF16.replace("Supplementary character 𐀀", "?", '!');
returns "Supplementary character 𐀀"
- Parameters:
source
- UTF16 format Unicode string which the replacements will be based on.oldStr
- non-zero-length string to be replaced.newStr
- the new string to replace oldStr- Returns:
- 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.
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reverse
public static java.lang.StringBuffer reverse(java.lang.StringBuffer source)
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 𐀀𐐁"))
returns "𐐁𐀀 sretcarahc yratnemelppuS".- Parameters:
source
- the source StringBuffer that contains UTF16 format Unicode string to be reversed- Returns:
- a modified source with reversed UTF16 format Unicode string.
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hasMoreCodePointsThan
public static boolean hasMoreCodePointsThan(java.lang.String source, int number)
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.- Parameters:
source
- The input string.number
- The number of code points in the string is compared against the 'number' parameter.- Returns:
- boolean value for whether the string contains more Unicode code points than 'number'.
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hasMoreCodePointsThan
public static boolean hasMoreCodePointsThan(char[] source, int start, int limit, int 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.- Parameters:
source
- array of UTF-16 charsstart
- offset to substring in the source array for analyzinglimit
- offset to substring in the source array for analyzingnumber
- The number of code points in the string is compared against the 'number' parameter.- Returns:
- boolean value for whether the string contains more Unicode code points than 'number'.
- Throws:
java.lang.IndexOutOfBoundsException
- thrown when limit < start
-
hasMoreCodePointsThan
public static boolean hasMoreCodePointsThan(java.lang.StringBuffer source, int 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.- Parameters:
source
- The input string buffer.number
- The number of code points in the string buffer is compared against the 'number' parameter.- Returns:
- boolean value for whether the string buffer contains more Unicode code points than 'number'.
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newString
public static java.lang.String newString(int[] codePoints, int offset, int count)
Cover JDK 1.5 API. Create a String from an array of codePoints.- Parameters:
codePoints
- the code arrayoffset
- the start of the text in the code point arraycount
- the number of code points- Returns:
- a String representing the code points between offset and count
- Throws:
java.lang.IllegalArgumentException
- if an invalid code point is encounteredjava.lang.IndexOutOfBoundsException
- if the offset or count are out of bounds.
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