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 * 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).
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 * 2 along with this work; if not, write to the Free Software Foundation,
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package org.graalvm.compiler.asm;

import org.graalvm.compiler.core.common.NumUtil;

import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.util.Arrays;

Code buffer management for the assembler.
/** * Code buffer management for the assembler. */
final class Buffer { protected ByteBuffer data; Buffer(ByteOrder order) { data = ByteBuffer.allocate(AsmOptions.InitialCodeBufferSize); data.order(order); } public int position() { return data.position(); } public void setPosition(int position) { assert position >= 0 && position <= data.limit(); data.position(position); }
Closes this buffer. Any further operations on a closed buffer will result in a NullPointerException.
Params:
  • trimmedCopy – if true, then a copy of the underlying byte array up to (but not including) position() is returned
Returns:the data in this buffer or a trimmed copy if trimmedCopy is true
/** * Closes this buffer. Any further operations on a closed buffer will result in a * {@link NullPointerException}. * * @param trimmedCopy if {@code true}, then a copy of the underlying byte array up to (but not * including) {@code position()} is returned * @return the data in this buffer or a trimmed copy if {@code trimmedCopy} is {@code true} */
public byte[] close(boolean trimmedCopy) { byte[] result = data.array(); if (trimmedCopy) { // Make a copy even if result.length == data.position() since // the API for trimmedCopy states a copy is always made result = Arrays.copyOf(result, data.position()); } data = null; return result; } public byte[] copyData(int start, int end) { if (data == null) { return null; } return Arrays.copyOfRange(data.array(), start, end); }
Copies the data from this buffer into a given array.
Params:
  • dst – the destination array
  • off – starting position in dst
  • len – number of bytes to copy
/** * Copies the data from this buffer into a given array. * * @param dst the destination array * @param off starting position in {@code dst} * @param len number of bytes to copy */
public void copyInto(byte[] dst, int off, int len) { System.arraycopy(data.array(), 0, dst, off, len); } protected void ensureSize(int length) { if (length >= data.limit()) { byte[] newBuf = Arrays.copyOf(data.array(), length * 4); ByteBuffer newData = ByteBuffer.wrap(newBuf); newData.order(data.order()); newData.position(data.position()); data = newData; } } public void emitBytes(byte[] arr, int off, int len) { ensureSize(data.position() + len); data.put(arr, off, len); } public void emitByte(int b) { assert NumUtil.isUByte(b) || NumUtil.isByte(b); ensureSize(data.position() + 1); data.put((byte) (b & 0xFF)); } public void emitShort(int b) { assert NumUtil.isUShort(b) || NumUtil.isShort(b); ensureSize(data.position() + 2); data.putShort((short) b); } public void emitInt(int b) { ensureSize(data.position() + 4); data.putInt(b); } public void emitLong(long b) { ensureSize(data.position() + 8); data.putLong(b); } public void emitBytes(byte[] arr, int pos) { final int len = arr.length; ensureSize(pos + len); // Write directly into the underlying array so as to not // change the ByteBuffer's position System.arraycopy(arr, 0, data.array(), pos, len); } public void emitByte(int b, int pos) { assert NumUtil.isUByte(b) || NumUtil.isByte(b); ensureSize(pos + 1); data.put(pos, (byte) (b & 0xFF)); } public void emitShort(int b, int pos) { assert NumUtil.isUShort(b) || NumUtil.isShort(b); ensureSize(pos + 2); data.putShort(pos, (short) b).position(); } public void emitInt(int b, int pos) { ensureSize(pos + 4); data.putInt(pos, b).position(); } public void emitLong(long b, int pos) { ensureSize(pos + 8); data.putLong(pos, b).position(); } public int getByte(int pos) { int b = data.get(pos); return b & 0xff; } public int getShort(int pos) { short s = data.getShort(pos); return s & 0xffff; } public int getInt(int pos) { return data.getInt(pos); } public void reset() { data.clear(); } }