/*
* Copyright (C) 2007 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*
* As per the Apache license requirements, this file has been modified
* from its original state.
*
* Such modifications are Copyright (C) 2010 Ben Gruver, and are released
* under the original license
*/
package org.jf.dexlib.Util;
import java.util.ArrayList;
/**
* Implementation of {@link AnnotatedOutput} which stores the written data
* into a <code>byte[]</code>.
*
* <p><b>Note:</b> As per the {@link Output} interface, multi-byte
* writes all use little-endian order.</p>
*/
public final class ByteArrayOutput implements Output
{
/** default size for stretchy instances */
private static final int DEFAULT_SIZE = 1000;
/**
* whether the instance is stretchy, that is, whether its array
* may be resized to increase capacity
*/
private final boolean stretchy;
/** non-null; the data itself */
private byte[] data;
/** >= 0; current output cursor */
private int cursor;
/** whether annotations are to be verbose */
private boolean verbose;
/**
* null-ok; list of annotations, or <code>null</code> if this instance
* isn't keeping them
*/
private ArrayList<Annotation> annotations;
/** >= 40 (if used); the desired maximum annotation width */
private int annotationWidth;
/**
* >= 8 (if used); the number of bytes of hex output to use
* in annotations
*/
private int hexCols;
/**
* Constructs an instance with a fixed maximum size. Note that the
* given array is the only one that will be used to store data. In
* particular, no reallocation will occur in order to expand the
* capacity of the resulting instance. Also, the constructed
* instance does not keep annotations by default.
*
* @param data non-null; data array to use for output
*/
public ByteArrayOutput(byte[] data) {
this(data, false);
}
/**
* Constructs a "stretchy" instance. The underlying array may be
* reallocated. The constructed instance does not keep annotations
* by default.
*/
public ByteArrayOutput() {
this(new byte[DEFAULT_SIZE], true);
}
/**
* Internal constructor.
*
* @param data non-null; data array to use for output
* @param stretchy whether the instance is to be stretchy
*/
private ByteArrayOutput(byte[] data, boolean stretchy) {
if (data == null) {
throw new NullPointerException("data == null");
}
this.stretchy = stretchy;
this.data = data;
this.cursor = 0;
this.verbose = false;
this.annotations = null;
this.annotationWidth = 0;
this.hexCols = 0;
}
/**
* Gets the underlying <code>byte[]</code> of this instance, which
* may be larger than the number of bytes written
*
* @see #toByteArray
*
* @return non-null; the <code>byte[]</code>
*/
public byte[] getArray() {
return data;
}
/**
* Constructs and returns a new <code>byte[]</code> that contains
* the written contents exactly (that is, with no extra unwritten
* bytes at the end).
*
* @see #getArray
*
* @return non-null; an appropriately-constructed array
*/
public byte[] toByteArray() {
byte[] result = new byte[cursor];
System.arraycopy(data, 0, result, 0, cursor);
return result;
}
/** {@inheritDoc} */
public int getCursor() {
return cursor;
}
/** {@inheritDoc} */
public void assertCursor(int expectedCursor) {
if (cursor != expectedCursor) {
throw new ExceptionWithContext("expected cursor " +
expectedCursor + "; actual value: " + cursor);
}
}
/** {@inheritDoc} */
public void writeByte(int value) {
int writeAt = cursor;
int end = writeAt + 1;
if (stretchy) {
ensureCapacity(end);
} else if (end > data.length) {
throwBounds();
return;
}
data[writeAt] = (byte) value;
cursor = end;
}
/** {@inheritDoc} */
public void writeShort(int value) {
int writeAt = cursor;
int end = writeAt + 2;
if (stretchy) {
ensureCapacity(end);
} else if (end > data.length) {
throwBounds();
return;
}
data[writeAt] = (byte) value;
data[writeAt + 1] = (byte) (value >> 8);
cursor = end;
}
/** {@inheritDoc} */
public void writeInt(int value) {
int writeAt = cursor;
int end = writeAt + 4;
if (stretchy) {
ensureCapacity(end);
} else if (end > data.length) {
throwBounds();
return;
}
data[writeAt] = (byte) value;
data[writeAt + 1] = (byte) (value >> 8);
data[writeAt + 2] = (byte) (value >> 16);
data[writeAt + 3] = (byte) (value >> 24);
cursor = end;
}
/** {@inheritDoc} */
public void writeLong(long value) {
int writeAt = cursor;
int end = writeAt + 8;
if (stretchy) {
ensureCapacity(end);
} else if (end > data.length) {
throwBounds();
return;
}
int half = (int) value;
data[writeAt] = (byte) half;
data[writeAt + 1] = (byte) (half >> 8);
data[writeAt + 2] = (byte) (half >> 16);
data[writeAt + 3] = (byte) (half >> 24);
half = (int) (value >> 32);
data[writeAt + 4] = (byte) half;
data[writeAt + 5] = (byte) (half >> 8);
data[writeAt + 6] = (byte) (half >> 16);
data[writeAt + 7] = (byte) (half >> 24);
cursor = end;
}
/** {@inheritDoc} */
public int writeUnsignedLeb128(int value) {
int remaining = value >>> 7;
int count = 0;
while (remaining != 0) {
writeByte((value & 0x7f) | 0x80);
value = remaining;
remaining >>>= 7;
count++;
}
writeByte(value & 0x7f);
return count + 1;
}
/** {@inheritDoc} */
public int writeSignedLeb128(int value) {
int remaining = value >> 7;
int count = 0;
boolean hasMore = true;
int end = ((value & Integer.MIN_VALUE) == 0) ? 0 : -1;
while (hasMore) {
hasMore = (remaining != end)
|| ((remaining & 1) != ((value >> 6) & 1));
writeByte((value & 0x7f) | (hasMore ? 0x80 : 0));
value = remaining;
remaining >>= 7;
count++;
}
return count;
}
/** {@inheritDoc} */
public void write(ByteArray bytes) {
int blen = bytes.size();
int writeAt = cursor;
int end = writeAt + blen;
if (stretchy) {
ensureCapacity(end);
} else if (end > data.length) {
throwBounds();
return;
}
bytes.getBytes(data, writeAt);
cursor = end;
}
/** {@inheritDoc} */
public void write(byte[] bytes, int offset, int length) {
int writeAt = cursor;
int end = writeAt + length;
int bytesEnd = offset + length;
// twos-complement math trick: ((x < 0) || (y < 0)) <=> ((x|y) < 0)
if (((offset | length | end) < 0) || (bytesEnd > bytes.length)) {
throw new IndexOutOfBoundsException("bytes.length " +
bytes.length + "; " +
offset + "..!" + end);
}
if (stretchy) {
ensureCapacity(end);
} else if (end > data.length) {
throwBounds();
return;
}
System.arraycopy(bytes, offset, data, writeAt, length);
cursor = end;
}
/** {@inheritDoc} */
public void write(byte[] bytes) {
write(bytes, 0, bytes.length);
}
/** {@inheritDoc} */
public void writeZeroes(int count) {
if (count < 0) {
throw new IllegalArgumentException("count < 0");
}
int end = cursor + count;
if (stretchy) {
ensureCapacity(end);
} else if (end > data.length) {
throwBounds();
return;
}
/*
* There is no need to actually write zeroes, since the array is
* already preinitialized with zeroes.
*/
cursor = end;
}
/** {@inheritDoc} */
public void alignTo(int alignment) {
int end = AlignmentUtils.alignOffset(cursor, alignment);
if (stretchy) {
ensureCapacity(end);
} else if (end > data.length) {
throwBounds();
return;
}
cursor = end;
}
/** {@inheritDoc} */
public boolean annotates() {
return (annotations != null);
}
/** {@inheritDoc} */
public boolean isVerbose() {
return verbose;
}
/** {@inheritDoc} */
public void annotate(String msg) {
if (annotations == null) {
return;
}
endAnnotation();
annotations.add(new Annotation(cursor, msg));
}
/** {@inheritDoc} */
public void annotate(int amt, String msg) {
if (annotations == null) {
return;
}
endAnnotation();
int asz = annotations.size();
int lastEnd = (asz == 0) ? 0 : annotations.get(asz - 1).getEnd();
int startAt;
if (lastEnd <= cursor) {
startAt = cursor;
} else {
startAt = lastEnd;
}
annotations.add(new Annotation(startAt, startAt + amt, msg));
}
/** {@inheritDoc} */
public void endAnnotation() {
if (annotations == null) {
return;
}
int sz = annotations.size();
if (sz != 0) {
annotations.get(sz - 1).setEndIfUnset(cursor);
}
}
/** {@inheritDoc} */
public int getAnnotationWidth() {
int leftWidth = 8 + (hexCols * 2) + (hexCols / 2);
return annotationWidth - leftWidth;
}
/**
* Indicates that this instance should keep annotations. This method may
* be called only once per instance, and only before any data has been
* written to the it.
*
* @param annotationWidth >= 40; the desired maximum annotation width
* @param verbose whether or not to indicate verbose annotations
*/
public void enableAnnotations(int annotationWidth, boolean verbose) {
if ((annotations != null) || (cursor != 0)) {
throw new RuntimeException("cannot enable annotations");
}
if (annotationWidth < 40) {
throw new IllegalArgumentException("annotationWidth < 40");
}
int hexCols = (((annotationWidth - 7) / 15) + 1) & ~1;
if (hexCols < 6) {
hexCols = 6;
} else if (hexCols > 10) {
hexCols = 10;
}
this.annotations = new ArrayList<Annotation>(1000);
this.annotationWidth = annotationWidth;
this.hexCols = hexCols;
this.verbose = verbose;
}
/**
* Finishes up annotation processing. This closes off any open
* annotations and removes annotations that don't refer to written
* data.
*/
public void finishAnnotating() {
// Close off the final annotation, if any.
endAnnotation();
// Remove annotations that refer to unwritten data.
if (annotations != null) {
int asz = annotations.size();
while (asz > 0) {
Annotation last = annotations.get(asz - 1);
if (last.getStart() > cursor) {
annotations.remove(asz - 1);
asz--;
} else if (last.getEnd() > cursor) {
last.setEnd(cursor);
break;
} else {
break;
}
}
}
}
/**
* Throws the excpetion for when an attempt is made to write past the
* end of the instance.
*/
private static void throwBounds() {
throw new IndexOutOfBoundsException("attempt to write past the end");
}
/**
* Reallocates the underlying array if necessary. Calls to this method
* should be guarded by a test of {@link #stretchy}.
*
* @param desiredSize >= 0; the desired minimum total size of the array
*/
private void ensureCapacity(int desiredSize) {
if (data.length < desiredSize) {
byte[] newData = new byte[desiredSize * 2 + 1000];
System.arraycopy(data, 0, newData, 0, cursor);
data = newData;
}
}
/**
* Annotation on output.
*/
private static class Annotation {
/** >= 0; start of annotated range (inclusive) */
private final int start;
/**
* >= 0; end of annotated range (exclusive);
* <code>Integer.MAX_VALUE</code> if unclosed
*/
private int end;
/** non-null; annotation text */
private final String text;
/**
* Constructs an instance.
*
* @param start >= 0; start of annotated range
* @param end >= start; end of annotated range (exclusive) or
* <code>Integer.MAX_VALUE</code> if unclosed
* @param text non-null; annotation text
*/
public Annotation(int start, int end, String text) {
this.start = start;
this.end = end;
this.text = text;
}
/**
* Constructs an instance. It is initally unclosed.
*
* @param start >= 0; start of annotated range
* @param text non-null; annotation text
*/
public Annotation(int start, String text) {
this(start, Integer.MAX_VALUE, text);
}
/**
* Sets the end as given, but only if the instance is unclosed;
* otherwise, do nothing.
*
* @param end >= start; the end
*/
public void setEndIfUnset(int end) {
if (this.end == Integer.MAX_VALUE) {
this.end = end;
}
}
/**
* Sets the end as given.
*
* @param end >= start; the end
*/
public void setEnd(int end) {
this.end = end;
}
/**
* Gets the start.
*
* @return the start
*/
public int getStart() {
return start;
}
/**
* Gets the end.
*
* @return the end
*/
public int getEnd() {
return end;
}
/**
* Gets the text.
*
* @return non-null; the text
*/
public String getText() {
return text;
}
}
}