soot.coffi.Utf8_Enumeration Maven / Gradle / Ivy
package soot.coffi;
/*-
* #%L
* Soot - a J*va Optimization Framework
* %%
* Copyright (C) 1997 Clark Verbrugge
* %%
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation, either version 2.1 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Lesser Public License for more details.
*
* You should have received a copy of the GNU General Lesser Public
* License along with this program. If not, see
* .
* #L%
*/
import java.util.Enumeration;
/**
* An enumeration of a Utf8 allows one to run through the characters in a unicode string; used primarily for comparing
* unicode strings. Note that unlike regular enumerations, and to be efficient (ie to avoid allocating an object in each call
* to nextElement), the return value is accessed by this object's 'c' field, and nextElement merely returns this.
*
* @see CONSTANT_Utf8_info
* @see Utf8_Enumeration#c
* @see Utf8_Enumeration#nextElement
* @author Clark Verbrugge
*/
public class Utf8_Enumeration implements Enumeration {
/**
* The latest character, as determined by nextElement.
*
* @see Utf8_Enumeration#nextElement
*/
public int c; // latest character
private short curindex;
private short length;
private byte bytes[];
/**
* For creating an empty enumeration; you must use reset() after this to initialize the enumeration.
*
* @see Utf8_Enumeration#reset
*/
public Utf8_Enumeration() {
}
/**
* For creating a normal enumeration of the given Utf8 string.
*
* @param b
* array of bytes in Utf8 format.
*/
public Utf8_Enumeration(byte b[]) {
bytes = b;
curindex = (short) 2;
length = (short) (((((bytes[0])) & 0xff) << 8) + (((bytes[1])) & 0xff) + 2);
}
/**
* Resets this object to be an enumeration of the given Utf8 string.
*
* @param b
* array of bytes in Utf8 format.
*/
public void reset(byte b[]) {
bytes = b;
curindex = (short) 2;
length = (short) (((((bytes[0])) & 0xff) << 8) + (((bytes[1])) & 0xff) + 2);
}
/** true if the entire string hasn't been enumerated yet. */
public boolean hasMoreElements() {
if (curindex < length) {
return true;
}
return false;
}
/**
* Determines the next Utf8 character, and stores it in c.
*
* @return this
* @see Utf8_Enumeration#c
*/
public Object nextElement() {
byte b;
b = bytes[curindex++];
if ((b & ((byte) 0x80)) == 0) { // one-byte character
c = b;
} else if ((b & ((byte) 0xe0)) == 0xc0) { // two-byte character
c = ((b & ((byte) 0x1f))) << 6;
b = bytes[curindex++];
c |= (b & ((byte) 0x3f));
} else { // three-byte character
c = ((b & ((byte) 0x0f))) << 12;
b = bytes[curindex++];
c |= ((b & ((byte) 0x3f))) << 6;
b = bytes[curindex++];
c |= (b & ((byte) 0x3f));
}
return this;
}
}