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6639458: Improvements to Surrogate.java

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Optimize Surrogate.java

Reviewed-by: sherman
This commit is contained in:
Martin Buchholz 2009-07-24 18:24:02 -07:00
parent 7ac7d3079f
commit 4d07a8cfb9
1 changed files with 44 additions and 48 deletions
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92
jdk/src/share/classes/sun/nio/cs/Surrogate.java
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@ -30,7 +30,6 @@ import java.nio.charset.CoderResult;
import java.nio.charset.MalformedInputException;
import java.nio.charset.UnmappableCharacterException;
/**
* Utility class for dealing with surrogates.
*
@ -41,19 +40,15 @@ public class Surrogate {
private Surrogate() { }
// UTF-16 surrogate-character ranges
//
public static final char MIN_HIGH = '\uD800';
public static final char MAX_HIGH = '\uDBFF';
public static final char MIN_LOW = '\uDC00';
public static final char MAX_LOW = '\uDFFF';
public static final char MIN = MIN_HIGH;
public static final char MAX = MAX_LOW;
// Range of UCS-4 values that need surrogates in UTF-16
//
public static final int UCS4_MIN = 0x10000;
public static final int UCS4_MAX = (1 << 20) + UCS4_MIN - 1;
// TODO: Deprecate/remove the following redundant definitions
public static final char MIN_HIGH = Character.MIN_HIGH_SURROGATE;
public static final char MAX_HIGH = Character.MAX_HIGH_SURROGATE;
public static final char MIN_LOW = Character.MIN_LOW_SURROGATE;
public static final char MAX_LOW = Character.MAX_LOW_SURROGATE;
public static final char MIN = Character.MIN_SURROGATE;
public static final char MAX = Character.MAX_SURROGATE;
public static final int UCS4_MIN = Character.MIN_SUPPLEMENTARY_CODE_POINT;
public static final int UCS4_MAX = Character.MAX_CODE_POINT;
/**
* Tells whether or not the given UTF-16 value is a high surrogate.
@ -76,36 +71,46 @@ public class Surrogate {
return (MIN <= c) && (c <= MAX);
}
/**
* Tells whether or not the given UCS-4 character is in the Basic
* Multilingual Plane, and can be represented using a single char.
*/
public static boolean isBMP(int uc) {
return (int) (char) uc == uc;
}
/**
* Tells whether or not the given UCS-4 character must be represented as a
* surrogate pair in UTF-16.
*/
public static boolean neededFor(int uc) {
return (uc >= UCS4_MIN) && (uc <= UCS4_MAX);
return Character.isSupplementaryCodePoint(uc);
}
/**
* Returns the high UTF-16 surrogate for the given UCS-4 character.
*/
public static char high(int uc) {
assert neededFor(uc);
return (char)(0xd800 | (((uc - UCS4_MIN) >> 10) & 0x3ff));
assert Character.isSupplementaryCodePoint(uc);
return (char)((uc >> 10)
+ (Character.MIN_HIGH_SURROGATE
- (Character.MIN_SUPPLEMENTARY_CODE_POINT >> 10)));
}
/**
* Returns the low UTF-16 surrogate for the given UCS-4 character.
*/
public static char low(int uc) {
assert neededFor(uc);
return (char)(0xdc00 | ((uc - UCS4_MIN) & 0x3ff));
assert Character.isSupplementaryCodePoint(uc);
return (char)((uc & 0x3ff) + Character.MIN_LOW_SURROGATE);
}
/**
* Converts the given surrogate pair into a 32-bit UCS-4 character.
*/
public static int toUCS4(char c, char d) {
assert isHigh(c) && isLow(d);
return (((c & 0x3ff) << 10) | (d & 0x3ff)) + 0x10000;
assert Character.isHighSurrogate(c) && Character.isLowSurrogate(d);
return Character.toCodePoint(c, d);
}
/**
@ -178,14 +183,14 @@ public class Surrogate {
* object
*/
public int parse(char c, CharBuffer in) {
if (Surrogate.isHigh(c)) {
if (Character.isHighSurrogate(c)) {
if (!in.hasRemaining()) {
error = CoderResult.UNDERFLOW;
return -1;
}
char d = in.get();
if (Surrogate.isLow(d)) {
character = toUCS4(c, d);
if (Character.isLowSurrogate(d)) {
character = Character.toCodePoint(c, d);
isPair = true;
error = null;
return character;
@ -193,7 +198,7 @@ public class Surrogate {
error = CoderResult.malformedForLength(1);
return -1;
}
if (Surrogate.isLow(c)) {
if (Character.isLowSurrogate(c)) {
error = CoderResult.malformedForLength(1);
return -1;
}
@ -220,14 +225,14 @@ public class Surrogate {
*/
public int parse(char c, char[] ia, int ip, int il) {
assert (ia[ip] == c);
if (Surrogate.isHigh(c)) {
if (Character.isHighSurrogate(c)) {
if (il - ip < 2) {
error = CoderResult.UNDERFLOW;
return -1;
}
char d = ia[ip + 1];
if (Surrogate.isLow(d)) {
character = toUCS4(c, d);
if (Character.isLowSurrogate(d)) {
character = Character.toCodePoint(c, d);
isPair = true;
error = null;
return character;
@ -235,7 +240,7 @@ public class Surrogate {
error = CoderResult.malformedForLength(1);
return -1;
}
if (Surrogate.isLow(c)) {
if (Character.isLowSurrogate(c)) {
error = CoderResult.malformedForLength(1);
return -1;
}
@ -282,7 +287,7 @@ public class Surrogate {
* error() will return a descriptive result object
*/
public int generate(int uc, int len, CharBuffer dst) {
if (uc <= 0xffff) {
if (Surrogate.isBMP(uc)) {
if (Surrogate.is(uc)) {
error = CoderResult.malformedForLength(len);
return -1;
@ -294,12 +299,7 @@ public class Surrogate {
dst.put((char)uc);
error = null;
return 1;
}
if (uc < Surrogate.UCS4_MIN) {
error = CoderResult.malformedForLength(len);
return -1;
}
if (uc <= Surrogate.UCS4_MAX) {
} else if (Character.isSupplementaryCodePoint(uc)) {
if (dst.remaining() < 2) {
error = CoderResult.OVERFLOW;
return -1;
@ -308,9 +308,10 @@ public class Surrogate {
dst.put(Surrogate.low(uc));
error = null;
return 2;
} else {
error = CoderResult.unmappableForLength(len);
return -1;
}
error = CoderResult.unmappableForLength(len);
return -1;
}
/**
@ -330,7 +331,7 @@ public class Surrogate {
* error() will return a descriptive result object
*/
public int generate(int uc, int len, char[] da, int dp, int dl) {
if (uc <= 0xffff) {
if (Surrogate.isBMP(uc)) {
if (Surrogate.is(uc)) {
error = CoderResult.malformedForLength(len);
return -1;
@ -342,12 +343,7 @@ public class Surrogate {
da[dp] = (char)uc;
error = null;
return 1;
}
if (uc < Surrogate.UCS4_MIN) {
error = CoderResult.malformedForLength(len);
return -1;
}
if (uc <= Surrogate.UCS4_MAX) {
} else if (Character.isSupplementaryCodePoint(uc)) {
if (dl - dp < 2) {
error = CoderResult.OVERFLOW;
return -1;
@ -356,11 +352,11 @@ public class Surrogate {
da[dp + 1] = Surrogate.low(uc);
error = null;
return 2;
} else {
error = CoderResult.unmappableForLength(len);
return -1;
}
error = CoderResult.unmappableForLength(len);
return -1;
}
}
}