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Java example source code file (Attribute.java)
The Attribute.java Java example source code/*** * ASM: a very small and fast Java bytecode manipulation framework * Copyright (c) 2000-2011 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. */ package clojure.asm; /** * A non standard class, field, method or code attribute. * * @author Eric Bruneton * @author Eugene Kuleshov */ public class Attribute { /** * The type of this attribute. */ public final String type; /** * The raw value of this attribute, used only for unknown attributes. */ byte[] value; /** * The next attribute in this attribute list. May be <tt>null. */ Attribute next; /** * Constructs a new empty attribute. * * @param type * the type of the attribute. */ protected Attribute(final String type) { this.type = type; } /** * Returns <tt>true if this type of attribute is unknown. The default * implementation of this method always returns <tt>true. * * @return <tt>true if this type of attribute is unknown. */ public boolean isUnknown() { return true; } /** * Returns <tt>true if this type of attribute is a code attribute. * * @return <tt>true if this type of attribute is a code attribute. */ public boolean isCodeAttribute() { return false; } /** * Returns the labels corresponding to this attribute. * * @return the labels corresponding to this attribute, or <tt>null if * this attribute is not a code attribute that contains labels. */ protected Label[] getLabels() { return null; } /** * Reads a {@link #type type} attribute. This method must return a * <i>new {@link Attribute} object, of type {@link #type type}, * corresponding to the <tt>len bytes starting at the given offset, in * the given class reader. * * @param cr * the class that contains the attribute to be read. * @param off * index of the first byte of the attribute's content in * {@link ClassReader#b cr.b}. The 6 attribute header bytes, * containing the type and the length of the attribute, are not * taken into account here. * @param len * the length of the attribute's content. * @param buf * buffer to be used to call {@link ClassReader#readUTF8 * readUTF8}, {@link ClassReader#readClass(int,char[]) readClass} * or {@link ClassReader#readConst readConst}. * @param codeOff * index of the first byte of code's attribute content in * {@link ClassReader#b cr.b}, or -1 if the attribute to be read * is not a code attribute. The 6 attribute header bytes, * containing the type and the length of the attribute, are not * taken into account here. * @param labels * the labels of the method's code, or <tt>null if the * attribute to be read is not a code attribute. * @return a <i>new {@link Attribute} object corresponding to the given * bytes. */ protected Attribute read(final ClassReader cr, final int off, final int len, final char[] buf, final int codeOff, final Label[] labels) { Attribute attr = new Attribute(type); attr.value = new byte[len]; System.arraycopy(cr.b, off, attr.value, 0, len); return attr; } /** * Returns the byte array form of this attribute. * * @param cw * the class to which this attribute must be added. This * parameter can be used to add to the constant pool of this * class the items that corresponds to this attribute. * @param code * the bytecode of the method corresponding to this code * attribute, or <tt>null if this attribute is not a code * attributes. * @param len * the length of the bytecode of the method corresponding to this * code attribute, or <tt>null if this attribute is not a * code attribute. * @param maxStack * the maximum stack size of the method corresponding to this * code attribute, or -1 if this attribute is not a code * attribute. * @param maxLocals * the maximum number of local variables of the method * corresponding to this code attribute, or -1 if this attribute * is not a code attribute. * @return the byte array form of this attribute. */ protected ByteVector write(final ClassWriter cw, final byte[] code, final int len, final int maxStack, final int maxLocals) { ByteVector v = new ByteVector(); v.data = value; v.length = value.length; return v; } /** * Returns the length of the attribute list that begins with this attribute. * * @return the length of the attribute list that begins with this attribute. */ final int getCount() { int count = 0; Attribute attr = this; while (attr != null) { count += 1; attr = attr.next; } return count; } /** * Returns the size of all the attributes in this attribute list. * * @param cw * the class writer to be used to convert the attributes into * byte arrays, with the {@link #write write} method. * @param code * the bytecode of the method corresponding to these code * attributes, or <tt>null if these attributes are not code * attributes. * @param len * the length of the bytecode of the method corresponding to * these code attributes, or <tt>null if these attributes * are not code attributes. * @param maxStack * the maximum stack size of the method corresponding to these * code attributes, or -1 if these attributes are not code * attributes. * @param maxLocals * the maximum number of local variables of the method * corresponding to these code attributes, or -1 if these * attributes are not code attributes. * @return the size of all the attributes in this attribute list. This size * includes the size of the attribute headers. */ final int getSize(final ClassWriter cw, final byte[] code, final int len, final int maxStack, final int maxLocals) { Attribute attr = this; int size = 0; while (attr != null) { cw.newUTF8(attr.type); size += attr.write(cw, code, len, maxStack, maxLocals).length + 6; attr = attr.next; } return size; } /** * Writes all the attributes of this attribute list in the given byte * vector. * * @param cw * the class writer to be used to convert the attributes into * byte arrays, with the {@link #write write} method. * @param code * the bytecode of the method corresponding to these code * attributes, or <tt>null if these attributes are not code * attributes. * @param len * the length of the bytecode of the method corresponding to * these code attributes, or <tt>null if these attributes * are not code attributes. * @param maxStack * the maximum stack size of the method corresponding to these * code attributes, or -1 if these attributes are not code * attributes. * @param maxLocals * the maximum number of local variables of the method * corresponding to these code attributes, or -1 if these * attributes are not code attributes. * @param out * where the attributes must be written. */ final void put(final ClassWriter cw, final byte[] code, final int len, final int maxStack, final int maxLocals, final ByteVector out) { Attribute attr = this; while (attr != null) { ByteVector b = attr.write(cw, code, len, maxStack, maxLocals); out.putShort(cw.newUTF8(attr.type)).putInt(b.length); out.putByteArray(b.data, 0, b.length); attr = attr.next; } } } Other Java examples (source code examples)Here is a short list of links related to this Java Attribute.java source code file: |
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