package org.simpleframework.xml.reflect;
import java.io.IOException;
import java.io.InputStream;
/***
* Portions Copyright (c) 2007 Paul Hammant Portions copyright (c)
* 2000-2007 INRIA, France Telecom All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met: 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer. 2.
* Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution. 3.
* Neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* A Java class parser to make a Class Visitor visit an existing class.
* This class parses a byte array conforming to the Java class file format
* and calls the appropriate visit methods of a given class visitor for
* each field, method and bytecode instruction encountered.
*
* @author Eric Bruneton
* @author Eugene Kuleshov
*/
class ClassReader {
/**
* The class to be parsed. <i>The content of this array must not be
* modified. This field is intended for Attribute sub classes, and is
* normally not needed by class generators or adapters.</i>
*/
public final byte[] b;
/**
* The start index of each constant pool item in {@link #b b}, plus
* one. The one byte offset skips the constant pool item tag that
* indicates its type.
*/
private final int[] items;
/**
* The String objects corresponding to the CONSTANT_Utf8 items. This
* cache avoids multiple parsing of a given CONSTANT_Utf8 constant pool
* item, which GREATLY improves performances (by a factor 2 to 3). This
* caching strategy could be extended to all constant pool items, but
* its benefit would not be so great for these items (because they are
* much less expensive to parse than CONSTANT_Utf8 items).
*/
private final String[] strings;
/**
* Maximum length of the strings contained in the constant pool of the
* class.
*/
private final int maxStringLength;
/**
* Start index of the class header information (access, name...) in
* {@link #b b}.
*/
public final int header;
/**
* The type of CONSTANT_Fieldref constant pool items.
*/
final static int FIELD = 9;
/**
* The type of CONSTANT_Methodref constant pool items.
*/
final static int METH = 10;
/**
* The type of CONSTANT_InterfaceMethodref constant pool items.
*/
final static int IMETH = 11;
/**
* The type of CONSTANT_Integer constant pool items.
*/
final static int INT = 3;
/**
* The type of CONSTANT_Float constant pool items.
*/
final static int FLOAT = 4;
/**
* The type of CONSTANT_Long constant pool items.
*/
final static int LONG = 5;
/**
* The type of CONSTANT_Double constant pool items.
*/
final static int DOUBLE = 6;
/**
* The type of CONSTANT_NameAndType constant pool items.
*/
final static int NAME_TYPE = 12;
/**
* The type of CONSTANT_Utf8 constant pool items.
*/
final static int UTF8 = 1;
// ------------------------------------------------------------------------
// Constructors
// ------------------------------------------------------------------------
/**
* Constructs a new {@link ClassReader} object.
*
* @param b
* the bytecode of the class to be read.
*/
private ClassReader(final byte[] b) {
this(b, 0);
}
/**
* Constructs a new {@link ClassReader} object.
*
* @param b
* the bytecode of the class to be read.
* @param off
* the start offset of the class data.
*/
private ClassReader(final byte[] b, final int off) {
this.b = b;
// parses the constant pool
items = new int[readUnsignedShort(off + 8)];
int n = items.length;
strings = new String[n];
int max = 0;
int index = off + 10;
for (int i = 1; i < n; ++i) {
items[i] = index + 1;
int size;
switch (b[index]) {
case FIELD:
case METH:
case IMETH:
case INT:
case FLOAT:
case NAME_TYPE:
size = 5;
break;
case LONG:
case DOUBLE:
size = 9;
++i;
break;
case UTF8:
size = 3 + readUnsignedShort(index + 1);
if (size > max) {
max = size;
}
break;
// case HamConstants.CLASS:
// case HamConstants.STR:
default:
size = 3;
break;
}
index += size;
}
maxStringLength = max;
// the class header information starts just after the constant pool
header = index;
}
/**
* Constructs a new {@link ClassReader} object.
*
* @param is
* an input stream from which to read the class.
* @throws IOException
* if a problem occurs during reading.
*/
public ClassReader(final InputStream is) throws IOException {
this(readClass(is));
}
/**
* Reads the bytecode of a class.
*
* @param is
* an input stream from which to read the class.
* @return the bytecode read from the given input stream.
* @throws IOException
* if a problem occurs during reading.
*/
private static byte[] readClass(final InputStream is)
throws IOException {
if (is == null) {
throw new IOException("Class not found");
}
byte[] b = new byte[is.available()];
int len = 0;
while (true) {
int n = is.read(b, len, b.length - len);
if (n == -1) {
if (len < b.length) {
byte[] c = new byte[len];
System.arraycopy(b, 0, c, 0, len);
b = c;
}
return b;
}
len += n;
if (len == b.length) {
int last = is.read();
if (last < 0) {
return b;
}
byte[] c = new byte[b.length + 1000];
System.arraycopy(b, 0, c, 0, len);
c[len++] = (byte) last;
b = c;
}
}
}
// ------------------------------------------------------------------------
// Public methods
// ------------------------------------------------------------------------
/**
* Makes the given visitor visit the Java class of this
* {@link ClassReader}. This class is the one specified in the
* constructor (see {@link #ClassReader(byte[]) ClassReader}).
*
* @param classVisitor
* the visitor that must visit this class.
*/
public void accept(final TypeCollector classVisitor) {
char[] c = new char[maxStringLength]; // buffer used to read strings
int i, j, k; // loop variables
int u, v, w; // indexes in b
String attrName;
int anns = 0;
int ianns = 0;
// visits the header
u = header;
v = items[readUnsignedShort(u + 4)];
int len = readUnsignedShort(u + 6);
w = 0;
u += 8;
for (i = 0; i < len; ++i) {
u += 2;
}
v = u;
i = readUnsignedShort(v);
v += 2;
for (; i > 0; --i) {
j = readUnsignedShort(v + 6);
v += 8;
for (; j > 0; --j) {
v += 6 + readInt(v + 2);
}
}
i = readUnsignedShort(v);
v += 2;
for (; i > 0; --i) {
j = readUnsignedShort(v + 6);
v += 8;
for (; j > 0; --j) {
v += 6 + readInt(v + 2);
}
}
i = readUnsignedShort(v);
v += 2;
for (; i > 0; --i) {
v += 6 + readInt(v + 2);
}
// annotations not needed.
// visits the fields
i = readUnsignedShort(u);
u += 2;
for (; i > 0; --i) {
j = readUnsignedShort(u + 6);
u += 8;
for (; j > 0; --j) {
u += 6 + readInt(u + 2);
}
}
// visits the methods
i = readUnsignedShort(u);
u += 2;
for (; i > 0; --i) {
// inlined in original ASM source, now a method call
u = readMethod(classVisitor, c, u);
}
}
private int readMethod(TypeCollector classVisitor, char[] c, int u) {
int v;
int w;
int j;
String attrName;
int k;
int access = readUnsignedShort(u);
String name = readUTF8(u + 2, c);
String desc = readUTF8(u + 4, c);
v = 0;
w = 0;
// looks for Code and Exceptions attributes
j = readUnsignedShort(u + 6);
u += 8;
for (; j > 0; --j) {
attrName = readUTF8(u, c);
int attrSize = readInt(u + 2);
u += 6;
// tests are sorted in decreasing frequency order
// (based on frequencies observed on typical classes)
if (attrName.equals("Code")) {
v = u;
}
u += attrSize;
}
// reads declared exceptions
if (w == 0) {
} else {
w += 2;
for (j = 0; j < readUnsignedShort(w); ++j) {
w += 2;
}
}
// visits the method's code, if any
MethodCollector mv = classVisitor.visitMethod(access, name, desc);
if (mv != null && v != 0) {
int codeLength = readInt(v + 4);
v += 8;
int codeStart = v;
int codeEnd = v + codeLength;
v = codeEnd;
j = readUnsignedShort(v);
v += 2;
for (; j > 0; --j) {
v += 8;
}
// parses the local variable, line number tables, and code
// attributes
int varTable = 0;
int varTypeTable = 0;
j = readUnsignedShort(v);
v += 2;
for (; j > 0; --j) {
attrName = readUTF8(v, c);
if (attrName.equals("LocalVariableTable")) {
varTable = v + 6;
} else if (attrName.equals("LocalVariableTypeTable")) {
varTypeTable = v + 6;
}
v += 6 + readInt(v + 2);
}
v = codeStart;
// visits the local variable tables
if (varTable != 0) {
if (varTypeTable != 0) {
k = readUnsignedShort(varTypeTable) * 3;
w = varTypeTable + 2;
int[] typeTable = new int[k];
while (k > 0) {
typeTable[--k] = w + 6; // signature
typeTable[--k] = readUnsignedShort(w + 8); // index
typeTable[--k] = readUnsignedShort(w); // start
w += 10;
}
}
k = readUnsignedShort(varTable);
w = varTable + 2;
for (; k > 0; --k) {
int index = readUnsignedShort(w + 8);
mv.visitLocalVariable(readUTF8(w + 4, c), index);
w += 10;
}
}
}
return u;
}
/**
* Reads an unsigned short value in {@link #b b}. <i>This method is
* intended for Attribute sub classes, and is normally not needed by
* class generators or adapters.</i>
*
* @param index
* the start index of the value to be read in {@link #b b}.
* @return the read value.
*/
private int readUnsignedShort(final int index) {
byte[] b = this.b;
return ((b[index] & 0xFF) << 8) | (b[index + 1] & 0xFF);
}
/**
* Reads a signed int value in {@link #b b}. <i>This method is intended
* for Attribute sub classes, and is normally not needed by class
* generators or adapters.</i>
*
* @param index
* the start index of the value to be read in {@link #b b}.
* @return the read value.
*/
private int readInt(final int index) {
byte[] b = this.b;
return ((b[index] & 0xFF) << 24) | ((b[index + 1] & 0xFF) << 16)
| ((b[index + 2] & 0xFF) << 8) | (b[index + 3] & 0xFF);
}
/**
* Reads an UTF8 string constant pool item in {@link #b b}. <i>This
* method is intended for Attribute sub classes, and is normally not
* needed by class generators or adapters.</i>
*
* @param index
* the start index of an unsigned short value in {@link #b b}
* , whose value is the index of an UTF8 constant pool item.
* @param buf
* buffer to be used to read the item. This buffer must be
* sufficiently large. It is not automatically resized.
* @return the String corresponding to the specified UTF8 item.
*/
private String readUTF8(int index, final char[] buf) {
int item = readUnsignedShort(index);
String s = strings[item];
if (s != null) {
return s;
}
index = items[item];
return strings[item] = readUTF(index + 2, readUnsignedShort(index),
buf);
}
/**
* Reads UTF8 string in {@link #b b}.
*
* @param index
* start offset of the UTF8 string to be read.
* @param utfLen
* length of the UTF8 string to be read.
* @param buf
* buffer to be used to read the string. This buffer must be
* sufficiently large. It is not automatically resized.
* @return the String corresponding to the specified UTF8 string.
*/
private String readUTF(int index, final int utfLen, final char[] buf) {
int endIndex = index + utfLen;
byte[] b = this.b;
int strLen = 0;
int c;
int st = 0;
char cc = 0;
while (index < endIndex) {
c = b[index++];
switch (st) {
case 0:
c = c & 0xFF;
if (c < 0x80) { // 0xxxxxxx
buf[strLen++] = (char) c;
} else if (c < 0xE0 && c > 0xBF) { // 110x xxxx 10xx xxxx
cc = (char) (c & 0x1F);
st = 1;
} else { // 1110 xxxx 10xx xxxx 10xx xxxx
cc = (char) (c & 0x0F);
st = 2;
}
break;
case 1: // byte 2 of 2-byte char or byte 3 of 3-byte char
buf[strLen++] = (char) ((cc << 6) | (c & 0x3F));
st = 0;
break;
case 2: // byte 2 of 3-byte char
cc = (char) ((cc << 6) | (c & 0x3F));
st = 1;
break;
}
}
return new String(buf, 0, strLen);
}
}