diff options
Diffstat (limited to 'libjava/classpath/java/lang/Character.java')
| -rw-r--r-- | libjava/classpath/java/lang/Character.java | 275 |
1 files changed, 269 insertions, 6 deletions
diff --git a/libjava/classpath/java/lang/Character.java b/libjava/classpath/java/lang/Character.java index 1e4f219a15f..78db41ef216 100644 --- a/libjava/classpath/java/lang/Character.java +++ b/libjava/classpath/java/lang/Character.java @@ -1,5 +1,5 @@ /* java.lang.Character -- Wrapper class for char, and Unicode subsets - Copyright (C) 1998, 1999, 2001, 2002 Free Software Foundation, Inc. + Copyright (C) 1998, 1999, 2001, 2002, 2005 Free Software Foundation, Inc. This file is part of GNU Classpath. @@ -1034,6 +1034,18 @@ public final class Character implements Serializable, Comparable public static final Class TYPE = VMClassLoader.getPrimitiveClass('C'); /** + * The number of bits needed to represent a <code>char</code>. + * @since 1.5 + */ + public static final int SIZE = 16; + + // This caches some Character values, and is used by boxing + // conversions via valueOf(). We must cache at least 0..127; + // this constant controls how much we actually cache. + private static final int MAX_CACHE = 127; + private static Character[] charCache = new Character[MAX_CACHE + 1]; + + /** * Lu = Letter, Uppercase (Informative). * * @since 1.1 @@ -1480,34 +1492,48 @@ public final class Character implements Serializable, Comparable /** - * Minimum high surrrogate code in UTF-16 encoding. + * Minimum high surrogate code in UTF-16 encoding. * * @since 1.5 */ public static final char MIN_HIGH_SURROGATE = '\ud800'; /** - * Maximum high surrrogate code in UTF-16 encoding. + * Maximum high surrogate code in UTF-16 encoding. * * @since 1.5 */ public static final char MAX_HIGH_SURROGATE = '\udbff'; /** - * Minimum low surrrogate code in UTF-16 encoding. + * Minimum low surrogate code in UTF-16 encoding. * * @since 1.5 */ public static final char MIN_LOW_SURROGATE = '\udc00'; /** - * Maximum low surrrogate code in UTF-16 encoding. + * Maximum low surrogate code in UTF-16 encoding. * * @since 1.5 */ public static final char MAX_LOW_SURROGATE = '\udfff'; /** + * Minimum surrogate code in UTF-16 encoding. + * + * @since 1.5 + */ + public static final char MIN_SURROGATE = MIN_HIGH_SURROGATE; + + /** + * Maximum low surrogate code in UTF-16 encoding. + * + * @since 1.5 + */ + public static final char MAX_SURROGATE = MAX_LOW_SURROGATE; + + /** * Grabs an attribute offset from the Unicode attribute database. The lower * 5 bits are the character type, the next 2 bits are flags, and the top * 9 bits are the offset into the attribute tables. @@ -2303,6 +2329,37 @@ public final class Character implements Serializable, Comparable } /** + * Returns an <code>Character</code> object wrapping the value. + * In contrast to the <code>Character</code> constructor, this method + * will cache some values. It is used by boxing conversion. + * + * @param val the value to wrap + * @return the <code>Character</code> + * + * @since 1.5 + */ + public static Character valueOf(char val) + { + if (val > MAX_CACHE) + return new Character(val); + synchronized (charCache) + { + if (charCache[val - MIN_VALUE] == null) + charCache[val - MIN_VALUE] = new Character(val); + return charCache[val - MIN_VALUE]; + } + } + + /** + * Reverse the bytes in val. + * @since 1.5 + */ + public static char reverseBytes(char val) + { + return (char) (((val >> 8) & 0xff) | ((val << 8) & 0xff00)); + } + + /** * Converts a unicode code point to a UTF-16 representation of that * code point. * @@ -2370,7 +2427,7 @@ public final class Character implements Serializable, Comparable * Return number of 16-bit characters required to represent the given * code point. * - * @param codePoint a uncode code point + * @param codePoint a unicode code point * * @return 2 if codePoint >= 0x10000, 1 otherwise. * @@ -2415,4 +2472,210 @@ public final class Character implements Serializable, Comparable { return codePoint >= MIN_CODE_POINT && codePoint <= MAX_CODE_POINT; } + + /** + * Return true if the given character is a high surrogate. + * @param ch the character + * @return true if the character is a high surrogate character + * + * @since 1.5 + */ + public static boolean isHighSurrogate(char ch) + { + return ch >= MIN_HIGH_SURROGATE && ch <= MAX_HIGH_SURROGATE; + } + + /** + * Return true if the given character is a low surrogate. + * @param ch the character + * @return true if the character is a low surrogate character + * + * @since 1.5 + */ + public static boolean isLowSurrogate(char ch) + { + return ch >= MIN_LOW_SURROGATE && ch <= MAX_LOW_SURROGATE; + } + + /** + * Return true if the given characters compose a surrogate pair. + * This is true if the first character is a high surrogate and the + * second character is a low surrogate. + * @param ch1 the first character + * @param ch2 the first character + * @return true if the characters compose a surrogate pair + * + * @since 1.5 + */ + public static boolean isSurrogatePair(char ch1, char ch2) + { + return isHighSurrogate(ch1) && isLowSurrogate(ch2); + } + + /** + * Given a valid surrogate pair, this returns the corresponding + * code point. + * @param high the high character of the pair + * @param low the low character of the pair + * @return the corresponding code point + * + * @since 1.5 + */ + public static int toCodePoint(char high, char low) + { + return ((high - MIN_HIGH_SURROGATE) << 10) + (low - MIN_LOW_SURROGATE); + } + + /** + * Get the code point at the specified index in the CharSequence. + * This is like CharSequence#charAt(int), but if the character is + * the start of a surrogate pair, and there is a following + * character, and this character completes the pair, then the + * corresponding supplementary code point is returned. Otherwise, + * the character at the index is returned. + * + * @param sequence the CharSequence + * @param index the index of the codepoint to get, starting at 0 + * @return the codepoint at the specified index + * @throws IndexOutOfBoundsException if index is negative or >= length() + * @since 1.5 + */ + public static int codePointAt(CharSequence sequence, int index) + { + int len = sequence.length(); + if (index < 0 || index >= len) + throw new IndexOutOfBoundsException(); + char high = sequence.charAt(index); + if (! isHighSurrogate(high) || ++index >= len) + return high; + char low = sequence.charAt(index); + if (! isLowSurrogate(low)) + return high; + return toCodePoint(high, low); + } + + /** + * Get the code point at the specified index in the CharSequence. + * If the character is the start of a surrogate pair, and there is a + * following character, and this character completes the pair, then + * the corresponding supplementary code point is returned. + * Otherwise, the character at the index is returned. + * + * @param chars the character array in which to look + * @param index the index of the codepoint to get, starting at 0 + * @return the codepoint at the specified index + * @throws IndexOutOfBoundsException if index is negative or >= length() + * @since 1.5 + */ + public static int codePointAt(char[] chars, int index) + { + return codePointAt(chars, index, chars.length); + } + + /** + * Get the code point at the specified index in the CharSequence. + * If the character is the start of a surrogate pair, and there is a + * following character within the specified range, and this + * character completes the pair, then the corresponding + * supplementary code point is returned. Otherwise, the character + * at the index is returned. + * + * @param chars the character array in which to look + * @param index the index of the codepoint to get, starting at 0 + * @param limit the limit past which characters should not be examined + * @return the codepoint at the specified index + * @throws IndexOutOfBoundsException if index is negative or >= + * limit, or if limit is negative or >= the length of the array + * @since 1.5 + */ + public static int codePointAt(char[] chars, int index, int limit) + { + if (index < 0 || index >= limit || limit < 0 || limit >= chars.length) + throw new IndexOutOfBoundsException(); + char high = chars[index]; + if (! isHighSurrogate(high) || ++index >= limit) + return high; + char low = chars[index]; + if (! isLowSurrogate(low)) + return high; + return toCodePoint(high, low); + } + + /** + * Get the code point before the specified index. This is like + * #codePointAt(char[], int), but checks the characters at + * <code>index-1</code> and <code>index-2</code> to see if they form + * a supplementary code point. If they do not, the character at + * <code>index-1</code> is returned. + * + * @param chars the character array + * @param index the index just past the codepoint to get, starting at 0 + * @return the codepoint at the specified index + * @throws IndexOutOfBoundsException if index is negative or >= length() + * @since 1.5 + */ + public static int codePointBefore(char[] chars, int index) + { + return codePointBefore(chars, index, 1); + } + + /** + * Get the code point before the specified index. This is like + * #codePointAt(char[], int), but checks the characters at + * <code>index-1</code> and <code>index-2</code> to see if they form + * a supplementary code point. If they do not, the character at + * <code>index-1</code> is returned. The start parameter is used to + * limit the range of the array which may be examined. + * + * @param chars the character array + * @param index the index just past the codepoint to get, starting at 0 + * @param start the index before which characters should not be examined + * @return the codepoint at the specified index + * @throws IndexOutOfBoundsException if index is > start or > + * the length of the array, or if limit is negative or >= the + * length of the array + * @since 1.5 + */ + public static int codePointBefore(char[] chars, int index, int start) + { + if (index < start || index > chars.length + || start < 0 || start >= chars.length) + throw new IndexOutOfBoundsException(); + --index; + char low = chars[index]; + if (! isLowSurrogate(low) || --index < start) + return low; + char high = chars[index]; + if (! isHighSurrogate(high)) + return low; + return toCodePoint(high, low); + } + + /** + * Get the code point before the specified index. This is like + * #codePointAt(CharSequence, int), but checks the characters at + * <code>index-1</code> and <code>index-2</code> to see if they form + * a supplementary code point. If they do not, the character at + * <code>index-1</code> is returned. + * + * @param sequence the CharSequence + * @param index the index just past the codepoint to get, starting at 0 + * @return the codepoint at the specified index + * @throws IndexOutOfBoundsException if index is negative or >= length() + * @since 1.5 + */ + public static int codePointBefore(CharSequence sequence, int index) + { + int len = sequence.length(); + if (index < 1 || index > len) + throw new IndexOutOfBoundsException(); + --index; + char low = sequence.charAt(index); + if (! isLowSurrogate(low) || --index < 0) + return low; + char high = sequence.charAt(index); + if (! isHighSurrogate(high)) + return low; + return toCodePoint(high, low); + } } // class Character |