Package com.oracle.truffle.api.strings

Class TruffleStringIterator

java.lang.Object

com.oracle.truffle.api.strings.TruffleStringIterator

public final class TruffleStringIterator
extends Object

An iterator object that allows iterating over a TruffleString's codepoints, without having to re-calculate codepoint indices on every access.

Usage Example:

 
 
 abstract static class SomeNode extends Node {

     @Specialization
     static void someSpecialization(
                     TruffleString string,
                     @Cached TruffleString.CreateCodePointIteratorNode createCodePointIteratorNode,
                     @Cached TruffleStringIterator.NextNode nextNode,
                     @Cached TruffleString.CodePointLengthNode codePointLengthNode,
                     @Cached TruffleString.CodePointAtIndexNode codePointAtIndexNode) {

         // iterating over a string's code points using TruffleStringIterator
         TruffleStringIterator iterator = createCodePointIteratorNode.execute(string, Encoding.UTF_8);
         while (iterator.hasNext()) {
             System.out.printf("%x%n", nextNode.execute(iterator));
         }

         // uncached variant:
         TruffleStringIterator iterator2 = string.createCodePointIteratorUncached(Encoding.UTF_8);
         while (iterator2.hasNext()) {
             System.out.printf("%x%n", iterator2.nextUncached());
         }

         // suboptimal variant: using CodePointAtIndexNode in a loop
         int codePointLength = codePointLengthNode.execute(string, Encoding.UTF_8);
         for (int i = 0; i < codePointLength; i++) {
             // performance problem: codePointAtIndexNode may have to calculate the byte index
             // corresponding
             // to codepoint index i for every loop iteration
             System.out.printf("%x%n", codePointAtIndexNode.execute(string, i, Encoding.UTF_8));
         }
     }
 }
 
 
 

Since:

22.1

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	TruffleStringIterator.NextNode	Returns the next codepoint in the string.
static class	TruffleStringIterator.PreviousNode	Returns the previous codepoint in the string.

Method Summary

Modifier and Type	Method	Description
int	getByteIndex()	Returns the next codepoint's byte index, where "byte index" refers the codepoint's first byte in forward mode, while in backward mode it refers to the first byte after the codepoint.
boolean	hasNext()	Returns true if there are more codepoints remaining.
boolean	hasPrevious()	Returns true if there are more codepoints remaining in reverse direction.
int	nextUncached()	Shorthand for calling the uncached version of TruffleStringIterator.NextNode.
int	previousUncached()	Shorthand for calling the uncached version of TruffleStringIterator.PreviousNode.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

hasNext

public boolean hasNext()

Returns true if there are more codepoints remaining.

Since:

22.1

hasPrevious

public boolean hasPrevious()

Returns true if there are more codepoints remaining in reverse direction.

Since:

22.1

getByteIndex

public int getByteIndex()

Returns the next codepoint's byte index, where "byte index" refers the codepoint's first byte in forward mode, while in backward mode it refers to the first byte after the codepoint.

Since:

22.3

nextUncached

public int nextUncached()

Shorthand for calling the uncached version of TruffleStringIterator.NextNode.

Since:

22.1

previousUncached

public int previousUncached()

Shorthand for calling the uncached version of TruffleStringIterator.PreviousNode.

Since:

22.1