| /* |
| * Copyright (c) 2015, 2015, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * 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). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| package org.graalvm.compiler.core.common.util; |
| |
| /** |
| * Provides low-level read access for signed and unsigned values of size 1, 2, 4, and 8 bytes. |
| */ |
| public interface TypeReader { |
| |
| /** Returns the next byte index to be read. */ |
| long getByteIndex(); |
| |
| /** Sets the next byte index to be read. */ |
| void setByteIndex(long byteIndex); |
| |
| /** Reads a signed 1 byte value. */ |
| int getS1(); |
| |
| /** Reads an unsigned 1 byte value. */ |
| int getU1(); |
| |
| /** Reads a signed 2 byte value. */ |
| int getS2(); |
| |
| /** Reads an unsigned 2 byte value. */ |
| int getU2(); |
| |
| /** Reads a signed 4 byte value. */ |
| int getS4(); |
| |
| /** Reads an unsigned 4 byte value. */ |
| long getU4(); |
| |
| /** Reads a signed 4 byte value. */ |
| long getS8(); |
| |
| /** |
| * Reads a signed value that has been written using {@link TypeWriter#putSV variable byte size |
| * encoding}. |
| */ |
| default long getSV() { |
| long result = 0; |
| int shift = 0; |
| long b; |
| do { |
| b = getU1(); |
| result |= (b & 0x7f) << shift; |
| shift += 7; |
| } while ((b & 0x80) != 0); |
| |
| if ((b & 0x40) != 0 && shift < 64) { |
| result |= -1L << shift; |
| } |
| return result; |
| } |
| |
| /** |
| * Reads a signed variable byte size encoded value that is known to fit into the range of int. |
| */ |
| default int getSVInt() { |
| return TypeConversion.asS4(getSV()); |
| } |
| |
| /** |
| * Reads an unsigned value that has been written using {@link TypeWriter#putSV variable byte |
| * size encoding}. |
| */ |
| default long getUV() { |
| long result = 0; |
| int shift = 0; |
| long b; |
| do { |
| b = getU1(); |
| result |= (b & 0x7f) << shift; |
| shift += 7; |
| } while ((b & 0x80) != 0); |
| |
| return result; |
| } |
| |
| /** |
| * Reads an unsigned variable byte size encoded value that is known to fit into the range of |
| * int. |
| */ |
| default int getUVInt() { |
| return TypeConversion.asS4(getUV()); |
| } |
| } |