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Rhino is an open-source implementation of JavaScript written entirely in Java. It is typically
embedded into Java applications to provide scripting to end users.
/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
package org.mozilla.classfile;
import org.mozilla.javascript.ObjToIntMap;
import org.mozilla.javascript.UintMap;
final class ConstantPool
{
ConstantPool(ClassFileWriter cfw)
{
this.cfw = cfw;
itsTopIndex = 1; // the zero'th entry is reserved
itsPool = new byte[ConstantPoolSize];
itsTop = 0;
}
private static final int ConstantPoolSize = 256;
static final byte
CONSTANT_Class = 7,
CONSTANT_Fieldref = 9,
CONSTANT_Methodref = 10,
CONSTANT_InterfaceMethodref = 11,
CONSTANT_String = 8,
CONSTANT_Integer = 3,
CONSTANT_Float = 4,
CONSTANT_Long = 5,
CONSTANT_Double = 6,
CONSTANT_NameAndType = 12,
CONSTANT_Utf8 = 1,
CONSTANT_MethodType = 16,
CONSTANT_MethodHandle = 15,
CONSTANT_InvokeDynamic = 18;
int write(byte[] data, int offset)
{
offset = ClassFileWriter.putInt16((short)itsTopIndex, data, offset);
System.arraycopy(itsPool, 0, data, offset, itsTop);
offset += itsTop;
return offset;
}
int getWriteSize()
{
return 2 + itsTop;
}
int addConstant(int k)
{
ensure(5);
itsPool[itsTop++] = CONSTANT_Integer;
itsTop = ClassFileWriter.putInt32(k, itsPool, itsTop);
itsPoolTypes.put(itsTopIndex, CONSTANT_Integer);
return (short)(itsTopIndex++);
}
int addConstant(long k)
{
ensure(9);
itsPool[itsTop++] = CONSTANT_Long;
itsTop = ClassFileWriter.putInt64(k, itsPool, itsTop);
int index = itsTopIndex;
itsTopIndex += 2;
itsPoolTypes.put(index, CONSTANT_Long);
return index;
}
int addConstant(float k)
{
ensure(5);
itsPool[itsTop++] = CONSTANT_Float;
int bits = Float.floatToIntBits(k);
itsTop = ClassFileWriter.putInt32(bits, itsPool, itsTop);
itsPoolTypes.put(itsTopIndex, CONSTANT_Float);
return itsTopIndex++;
}
int addConstant(double k)
{
ensure(9);
itsPool[itsTop++] = CONSTANT_Double;
long bits = Double.doubleToLongBits(k);
itsTop = ClassFileWriter.putInt64(bits, itsPool, itsTop);
int index = itsTopIndex;
itsTopIndex += 2;
itsPoolTypes.put(index, CONSTANT_Double);
return index;
}
int addConstant(String k)
{
int utf8Index = 0xFFFF & addUtf8(k);
int theIndex = itsStringConstHash.getInt(utf8Index, -1);
if (theIndex == -1) {
theIndex = itsTopIndex++;
ensure(3);
itsPool[itsTop++] = CONSTANT_String;
itsTop = ClassFileWriter.putInt16(utf8Index, itsPool, itsTop);
itsStringConstHash.put(utf8Index, theIndex);
}
itsPoolTypes.put(theIndex, CONSTANT_String);
return theIndex;
}
int addConstant(Object value) {
if (value instanceof Integer || value instanceof Byte
|| value instanceof Short) {
return addConstant(((Number) value).intValue());
} else if (value instanceof Character) {
return addConstant(((Character) value).charValue());
} else if (value instanceof Boolean) {
return addConstant(((Boolean) value).booleanValue() ? 1 : 0);
} else if (value instanceof Float) {
return addConstant(((Float) value).floatValue());
} else if (value instanceof Long) {
return addConstant(((Long) value).longValue());
} else if (value instanceof Double) {
return addConstant(((Double) value).doubleValue());
} else if (value instanceof String) {
return addConstant((String) value);
//} else if (value instanceof ClassFileWriter.MethodType) {
// return addMethodType((ClassFileWriter.MethodType) value);
} else if (value instanceof ClassFileWriter.MHandle) {
return addMethodHandle((ClassFileWriter.MHandle) value);
} else {
throw new IllegalArgumentException("value " + value);
}
}
boolean isUnderUtfEncodingLimit(String s)
{
int strLen = s.length();
if (strLen * 3 <= MAX_UTF_ENCODING_SIZE) {
return true;
} else if (strLen > MAX_UTF_ENCODING_SIZE) {
return false;
}
return strLen == getUtfEncodingLimit(s, 0, strLen);
}
/**
* Get maximum i such that start <= i <= end and
* s.substring(start, i) fits JVM UTF string encoding limit.
*/
int getUtfEncodingLimit(String s, int start, int end)
{
if ((end - start) * 3 <= MAX_UTF_ENCODING_SIZE) {
return end;
}
int limit = MAX_UTF_ENCODING_SIZE;
for (int i = start; i != end; i++) {
int c = s.charAt(i);
if (0 != c && c <= 0x7F) {
--limit;
} else if (c < 0x7FF) {
limit -= 2;
} else {
limit -= 3;
}
if (limit < 0) {
return i;
}
}
return end;
}
short addUtf8(String k)
{
int theIndex = itsUtf8Hash.get(k, -1);
if (theIndex == -1) {
int strLen = k.length();
boolean tooBigString;
if (strLen > MAX_UTF_ENCODING_SIZE) {
tooBigString = true;
} else {
tooBigString = false;
// Ask for worst case scenario buffer when each char takes 3
// bytes
ensure(1 + 2 + strLen * 3);
int top = itsTop;
itsPool[top++] = CONSTANT_Utf8;
top += 2; // skip length
char[] chars = cfw.getCharBuffer(strLen);
k.getChars(0, strLen, chars, 0);
for (int i = 0; i != strLen; i++) {
int c = chars[i];
if (c != 0 && c <= 0x7F) {
itsPool[top++] = (byte)c;
} else if (c > 0x7FF) {
itsPool[top++] = (byte)(0xE0 | (c >> 12));
itsPool[top++] = (byte)(0x80 | ((c >> 6) & 0x3F));
itsPool[top++] = (byte)(0x80 | (c & 0x3F));
} else {
itsPool[top++] = (byte)(0xC0 | (c >> 6));
itsPool[top++] = (byte)(0x80 | (c & 0x3F));
}
}
int utfLen = top - (itsTop + 1 + 2);
if (utfLen > MAX_UTF_ENCODING_SIZE) {
tooBigString = true;
} else {
// Write back length
itsPool[itsTop + 1] = (byte)(utfLen >>> 8);
itsPool[itsTop + 2] = (byte)utfLen;
itsTop = top;
theIndex = itsTopIndex++;
itsUtf8Hash.put(k, theIndex);
}
}
if (tooBigString) {
throw new IllegalArgumentException("Too big string");
}
}
setConstantData(theIndex, k);
itsPoolTypes.put(theIndex, CONSTANT_Utf8);
return (short)theIndex;
}
private short addNameAndType(String name, String type)
{
short nameIndex = addUtf8(name);
short typeIndex = addUtf8(type);
ensure(5);
itsPool[itsTop++] = CONSTANT_NameAndType;
itsTop = ClassFileWriter.putInt16(nameIndex, itsPool, itsTop);
itsTop = ClassFileWriter.putInt16(typeIndex, itsPool, itsTop);
itsPoolTypes.put(itsTopIndex, CONSTANT_NameAndType);
return (short)(itsTopIndex++);
}
short addClass(String className)
{
int theIndex = itsClassHash.get(className, -1);
if (theIndex == -1) {
String slashed = className;
if (className.indexOf('.') > 0) {
slashed = ClassFileWriter.getSlashedForm(className);
theIndex = itsClassHash.get(slashed, -1);
if (theIndex != -1) {
itsClassHash.put(className, theIndex);
}
}
if (theIndex == -1) {
int utf8Index = addUtf8(slashed);
ensure(3);
itsPool[itsTop++] = CONSTANT_Class;
itsTop = ClassFileWriter.putInt16(utf8Index, itsPool, itsTop);
theIndex = itsTopIndex++;
itsClassHash.put(slashed, theIndex);
if (!className.equals(slashed)) {
itsClassHash.put(className, theIndex);
}
}
}
setConstantData(theIndex, className);
itsPoolTypes.put(theIndex, CONSTANT_Class);
return (short)theIndex;
}
short addFieldRef(String className, String fieldName, String fieldType)
{
FieldOrMethodRef ref = new FieldOrMethodRef(className, fieldName,
fieldType);
int theIndex = itsFieldRefHash.get(ref, -1);
if (theIndex == -1) {
short ntIndex = addNameAndType(fieldName, fieldType);
short classIndex = addClass(className);
ensure(5);
itsPool[itsTop++] = CONSTANT_Fieldref;
itsTop = ClassFileWriter.putInt16(classIndex, itsPool, itsTop);
itsTop = ClassFileWriter.putInt16(ntIndex, itsPool, itsTop);
theIndex = itsTopIndex++;
itsFieldRefHash.put(ref, theIndex);
}
setConstantData(theIndex, ref);
itsPoolTypes.put(theIndex, CONSTANT_Fieldref);
return (short)theIndex;
}
short addMethodRef(String className, String methodName,
String methodType)
{
FieldOrMethodRef ref = new FieldOrMethodRef(className, methodName,
methodType);
int theIndex = itsMethodRefHash.get(ref, -1);
if (theIndex == -1) {
short ntIndex = addNameAndType(methodName, methodType);
short classIndex = addClass(className);
ensure(5);
itsPool[itsTop++] = CONSTANT_Methodref;
itsTop = ClassFileWriter.putInt16(classIndex, itsPool, itsTop);
itsTop = ClassFileWriter.putInt16(ntIndex, itsPool, itsTop);
theIndex = itsTopIndex++;
itsMethodRefHash.put(ref, theIndex);
}
setConstantData(theIndex, ref);
itsPoolTypes.put(theIndex, CONSTANT_Methodref);
return (short)theIndex;
}
short addInterfaceMethodRef(String className,
String methodName, String methodType)
{
short ntIndex = addNameAndType(methodName, methodType);
short classIndex = addClass(className);
ensure(5);
itsPool[itsTop++] = CONSTANT_InterfaceMethodref;
itsTop = ClassFileWriter.putInt16(classIndex, itsPool, itsTop);
itsTop = ClassFileWriter.putInt16(ntIndex, itsPool, itsTop);
FieldOrMethodRef r = new FieldOrMethodRef(className, methodName,
methodType);
setConstantData(itsTopIndex, r);
itsPoolTypes.put(itsTopIndex, CONSTANT_InterfaceMethodref);
return (short)(itsTopIndex++);
}
short addInvokeDynamic(String methodName, String methodType, int bootstrapIndex)
{
ConstantEntry entry = new ConstantEntry(CONSTANT_InvokeDynamic,
bootstrapIndex, methodName, methodType);
int theIndex = itsConstantHash.get(entry, -1);
if (theIndex == -1) {
short nameTypeIndex = addNameAndType(methodName, methodType);
ensure(5);
itsPool[itsTop++] = CONSTANT_InvokeDynamic;
itsTop = ClassFileWriter.putInt16(bootstrapIndex, itsPool, itsTop);
itsTop = ClassFileWriter.putInt16(nameTypeIndex, itsPool, itsTop);
theIndex = itsTopIndex++;
itsConstantHash.put(entry, theIndex);
setConstantData(theIndex, methodType);
itsPoolTypes.put(theIndex, CONSTANT_InvokeDynamic);
}
return (short)(theIndex);
}
short addMethodHandle(ClassFileWriter.MHandle mh)
{
int theIndex = itsConstantHash.get(mh, -1);
if (theIndex == -1) {
short ref;
if (mh.tag <= ByteCode.MH_PUTSTATIC) {
ref = addFieldRef(mh.owner, mh.name, mh.desc);
} else if (mh.tag == ByteCode.MH_INVOKEINTERFACE) {
ref = addInterfaceMethodRef(mh.owner, mh.name, mh.desc);
} else {
ref = addMethodRef(mh.owner, mh.name, mh.desc);
}
ensure(4);
itsPool[itsTop++] = CONSTANT_MethodHandle;
itsPool[itsTop++] = mh.tag;
itsTop = ClassFileWriter.putInt16(ref, itsPool, itsTop);
theIndex = itsTopIndex++;
itsConstantHash.put(mh, theIndex);
itsPoolTypes.put(theIndex, CONSTANT_MethodHandle);
}
return (short)(theIndex);
}
Object getConstantData(int index)
{
return itsConstantData.getObject(index);
}
void setConstantData(int index, Object data)
{
itsConstantData.put(index, data);
}
byte getConstantType(int index)
{
return (byte) itsPoolTypes.getInt(index, 0);
}
private void ensure(int howMuch)
{
if (itsTop + howMuch > itsPool.length) {
int newCapacity = itsPool.length * 2;
if (itsTop + howMuch > newCapacity) {
newCapacity = itsTop + howMuch;
}
byte[] tmp = new byte[newCapacity];
System.arraycopy(itsPool, 0, tmp, 0, itsTop);
itsPool = tmp;
}
}
private ClassFileWriter cfw;
private static final int MAX_UTF_ENCODING_SIZE = 65535;
private UintMap itsStringConstHash = new UintMap();
private ObjToIntMap itsUtf8Hash = new ObjToIntMap();
private ObjToIntMap itsFieldRefHash = new ObjToIntMap();
private ObjToIntMap itsMethodRefHash = new ObjToIntMap();
private ObjToIntMap itsClassHash = new ObjToIntMap();
private ObjToIntMap itsConstantHash = new ObjToIntMap();
private int itsTop;
private int itsTopIndex;
private UintMap itsConstantData = new UintMap();
private UintMap itsPoolTypes = new UintMap();
private byte itsPool[];
}
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