/*
* Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code 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 Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
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*/
package sun.jvm.hotspot.interpreter;
import sun.jvm.hotspot.oops.*;
import sun.jvm.hotspot.runtime.*;
import sun.jvm.hotspot.utilities.*;
public class BytecodeStream {
private Method _method;
// reading position
private int _bci; // bci if current bytecode
private int _next_bci; // bci of next bytecode
private int _end_bci; // bci after the current iteration interval
// last bytecode read
private int _code;
private boolean _is_wide;
// Construction
public BytecodeStream(Method method) {
_method = method;
setInterval(0, (int) method.getCodeSize());
}
// Iteration control
public void setInterval(int beg_bci, int end_bci) {
if (Assert.ASSERTS_ENABLED) {
Assert.that(0 <= beg_bci && beg_bci <= _method.getCodeSize(), "illegal beg_bci");
Assert.that(0 <= end_bci && end_bci <= _method.getCodeSize(), "illegal end_bci");
}
// setup of iteration pointers
_bci = beg_bci;
_next_bci = beg_bci;
_end_bci = end_bci;
}
public void setStart(int beg_bci) {
setInterval(beg_bci, (int) _method.getCodeSize());
}
// Iteration
public int next() {
int code;
// set reading position
_bci = _next_bci;
if (isLastBytecode()) {
// indicate end of bytecode stream
code = Bytecodes._illegal;
} else {
// get bytecode
int rawCode = Bytecodes.codeAt(_method, _bci);
code = 0; // Make javac happy
try {
code = Bytecodes.javaCode(rawCode);
} catch (AssertionFailure e) {
e.printStackTrace();
Assert.that(false, "Failure occurred at bci " + _bci + " in method " + _method.externalNameAndSignature());
}
// set next bytecode position
//
int l = Bytecodes.lengthFor(code);
if (l == 0) l = Bytecodes.lengthAt(_method, _bci);
_next_bci += l;
if (Assert.ASSERTS_ENABLED) {
Assert.that(_bci < _next_bci, "length must be > 0");
}
// set attributes
_is_wide = false;
// check for special (uncommon) cases
if (code == Bytecodes._wide) {
code = _method.getBytecodeOrBPAt(_bci + 1);
_is_wide = true;
}
if (Assert.ASSERTS_ENABLED) {
Assert.that(Bytecodes.isJavaCode(code), "sanity check");
}
}
_code = code;
return _code;
}
// Stream attributes
public Method method() { return _method; }
public int bci() { return _bci; }
public int nextBCI() { return _next_bci; }
public int endBCI() { return _end_bci; }
public int code() { return _code; }
public boolean isWide() { return _is_wide; }
public boolean isActiveBreakpoint() { return Bytecodes.isActiveBreakpointAt(_method, _bci); }
public boolean isLastBytecode() { return _next_bci >= _end_bci; }
// State changes
public void setNextBCI(int bci) {
if (Assert.ASSERTS_ENABLED) {
Assert.that(0 <= bci && bci <= _method.getCodeSize(), "illegal bci");
}
_next_bci = bci;
}
// Bytecode-specific attributes
public int dest() { return bci() + _method.getBytecodeShortArg(bci() + 1); }
public int dest_w() { return bci() + _method.getBytecodeIntArg(bci() + 1); }
// Unsigned indices, widening
public int getIndex() { return (isWide())
? (_method.getBytecodeShortArg(bci() + 2) & 0xFFFF)
: (_method.getBytecodeOrBPAt(bci() + 1) & 0xFF); }
public int getIndexU1() { return _method.getBytecodeOrBPAt(bci() + 1) & 0xFF; }
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