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package com.sun.jdo.api.persistence.enhancer.classfile;
/**
* Environment for decoding byte codes into instructions
*/
class InsnReadEnv {
/* The parent method environment */
private CodeEnv codeEnv;
/* The byte codes to be decoded */
private byte[] byteCodes;
/* The index into byteCodes for the next instruction to be decoded */
private int currPc;
/**
* Constructor
*/
InsnReadEnv(byte[] bytes, CodeEnv codeEnv) {
this.byteCodes = bytes;
this.currPc = 0;
this.codeEnv = codeEnv;
}
/**
* Return the index of the next instruction to decode
*/
int currentPC() {
return currPc;
}
/**
* Are there more byte codes to decode?
*/
boolean more() {
return currPc < byteCodes.length;
}
/**
* Get a single byte from the byte code stream
*/
byte getByte() {
if (!more())
throw new InsnError("out of byte codes");//NOI18N
return byteCodes[currPc++];
}
/**
* Get a single unsigned byte from the byte code stream
*/
int getUByte() {
return getByte() & 0xff;
}
/**
* Get a short from the byte code stream
*/
int getShort() {
byte byte1 = byteCodes[currPc++];
byte byte2 = byteCodes[currPc++];
return (byte1 << 8) | (byte2 & 0xff);
}
/**
* Get an unsigned short from the byte code stream
*/
int getUShort() {
return getShort() & 0xffff;
}
/**
* Get an int from the byte code stream
*/
int getInt() {
byte byte1 = byteCodes[currPc++];
byte byte2 = byteCodes[currPc++];
byte byte3 = byteCodes[currPc++];
byte byte4 = byteCodes[currPc++];
return (byte1 << 24) | ((byte2 & 0xff) << 16) |
((byte3 & 0xff) << 8) | (byte4 & 0xff);
}
/**
* Get the constant pool which applies to the method being decoded
*/
ConstantPool pool() {
return codeEnv.pool();
}
/**
* Get the canonical InsnTarget instance for the specified
* pc within the method.
*/
InsnTarget getTarget(int targ) {
return codeEnv.getTarget(targ);
}
}