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6639443: Character.toCodePoint and Character.toSurrogates can be optimized

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Rearranging code saves 5 bytes of bytecode

Reviewed-by: sherman
This commit is contained in:
Martin Buchholz 2009-07-24 18:16:14 -07:00
parent 3bb5216024
commit 7ac7d3079f
1 changed files with 11 additions and 5 deletions
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16
jdk/src/share/classes/java/lang/Character.java
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@ -2784,8 +2784,13 @@ class Character extends Object implements java.io.Serializable, Comparable<Chara
* @since 1.5
*/
public static int toCodePoint(char high, char low) {
return ((high - MIN_HIGH_SURROGATE) << 10)
+ (low - MIN_LOW_SURROGATE) + MIN_SUPPLEMENTARY_CODE_POINT;
// Optimized form of:
// return ((high - MIN_HIGH_SURROGATE) << 10)
// + (low - MIN_LOW_SURROGATE)
// + MIN_SUPPLEMENTARY_CODE_POINT;
return ((high << 10) + low) + (MIN_SUPPLEMENTARY_CODE_POINT
- (MIN_HIGH_SURROGATE << 10)
- MIN_LOW_SURROGATE);
}
/**
@ -3071,9 +3076,10 @@ class Character extends Object implements java.io.Serializable, Comparable<Chara
}
static void toSurrogates(int codePoint, char[] dst, int index) {
int offset = codePoint - MIN_SUPPLEMENTARY_CODE_POINT;
dst[index+1] = (char)((offset & 0x3ff) + MIN_LOW_SURROGATE);
dst[index] = (char)((offset >>> 10) + MIN_HIGH_SURROGATE);
// We write elements "backwards" to guarantee all-or-nothing
dst[index+1] = (char)((codePoint & 0x3ff) + MIN_LOW_SURROGATE);
dst[index] = (char)((codePoint >>> 10)
+ (MIN_HIGH_SURROGATE - (MIN_SUPPLEMENTARY_CODE_POINT >>> 10)));
}
/**