
2006-08-14 Mark Wielaard <mark@klomp.org> Imported GNU Classpath 0.92 * HACKING: Add more importing hints. Update automake version requirement. * configure.ac (gconf-peer): New enable AC argument. Add --disable-gconf-peer and --enable-default-preferences-peer to classpath configure when gconf is disabled. * scripts/makemake.tcl: Set gnu/java/util/prefs/gconf and gnu/java/awt/dnd/peer/gtk to bc. Classify gnu/java/security/Configuration.java as generated source file. * gnu/java/lang/management/VMGarbageCollectorMXBeanImpl.java, gnu/java/lang/management/VMMemoryPoolMXBeanImpl.java, gnu/java/lang/management/VMClassLoadingMXBeanImpl.java, gnu/java/lang/management/VMRuntimeMXBeanImpl.java, gnu/java/lang/management/VMMemoryManagerMXBeanImpl.java, gnu/java/lang/management/VMThreadMXBeanImpl.java, gnu/java/lang/management/VMMemoryMXBeanImpl.java, gnu/java/lang/management/VMCompilationMXBeanImpl.java: New VM stub classes. * java/lang/management/VMManagementFactory.java: Likewise. * java/net/VMURLConnection.java: Likewise. * gnu/java/nio/VMChannel.java: Likewise. * java/lang/Thread.java (getState): Add stub implementation. * java/lang/Class.java (isEnum): Likewise. * java/lang/Class.h (isEnum): Likewise. * gnu/awt/xlib/XToolkit.java (getClasspathTextLayoutPeer): Removed. * javax/naming/spi/NamingManager.java: New override for StackWalker functionality. * configure, sources.am, Makefile.in, gcj/Makefile.in, include/Makefile.in, testsuite/Makefile.in: Regenerated. From-SVN: r116139
207 lines
6 KiB
Java
207 lines
6 KiB
Java
/* HuffmanTable.java --
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Copyright (C) 2006 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301 USA.
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Linking this library statically or dynamically with other modules is
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making a combined work based on this library. Thus, the terms and
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conditions of the GNU General Public License cover the whole
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combination.
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent
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modules, and to copy and distribute the resulting executable under
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terms of your choice, provided that you also meet, for each linked
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independent module, the terms and conditions of the license of that
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module. An independent module is a module which is not derived from
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or based on this library. If you modify this library, you may extend
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this exception to your version of the library, but you are not
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obligated to do so. If you do not wish to do so, delete this
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exception statement from your version. */
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package gnu.javax.imageio.jpeg;
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import java.io.IOException;
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import javax.imageio.plugins.jpeg.JPEGHuffmanTable;
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/**
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* This Object construct a JPEGHuffmanTable which can be used to encode/decode
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* a scan from a JPEG codec stream. The table must be initalized with either a
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* BITS byte amount and a Huffman Table Value for decoding or a Huffman Size
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* and Huffman Code table for encoding.
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*/
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public class HuffmanTable
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{
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public final static int HUFFMAN_MAX_TABLES = 4;
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private short[] huffcode = new short[256];
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private short[] huffsize = new short[256];
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private short[] EHUFCO;
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private short[] EHUFSI;
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private short[] valptr = new short[16];
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private short[] mincode = {-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1,-1,-1};
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private short[] maxcode = {-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1};
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private short[] huffval;
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private short[] bits;
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static byte JPEG_DC_TABLE = 0;
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static byte JPEG_AC_TABLE = 1;
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private short lastk = 0;
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public HuffmanTable(JPEGHuffmanTable table)
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{
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huffcode = table.getValues();
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bits = table.getLengths();
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}
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/**
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* Generated from FIGURE C.1 - Generation of table of Huffman code sizes on
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* ISO DIS 10918-1. Requirements and Guidelines
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*/
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private void generateSizeTable()
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{
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short index=0;
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for(short i=0; i < bits.length ; i++)
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{
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for(short j=0; j < bits[i] ; j++)
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{
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huffsize[index] = (short) (i+1);
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index++;
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}
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}
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lastk = index;
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}
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/**
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* Generated from FIGURE C.2 - Generation of table of Huffman codes on
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* ISO DIS 10918-1. Requirements and Guidelines
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*/
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private void generateCodeTable()
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{
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short k=0;
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short si = huffsize[0];
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short code = 0;
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for(short i=0; i < huffsize.length ; i++)
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{
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while(huffsize[k]==si)
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{
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huffcode[k] = code;
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code++;
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k++;
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}
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code <<= 1;
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si++;
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}
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}
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/**
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* Generated from FIGURE F.15 - Generation of decode table generation on
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* ISO DIS 10918-1. Requirements and Guidelines
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*/
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private void generateDecoderTables()
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{
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short bitcount = 0;
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for(int i=0; i < 16 ; i++)
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{
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if(bits[i]!=0)
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valptr[i] = bitcount;
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for(int j=0 ; j < bits[i] ; j++)
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{
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if(huffcode[j+bitcount] < mincode[i] || mincode[i] == -1)
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mincode[i] = huffcode[j+bitcount];
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if(huffcode[j+bitcount] > maxcode[i])
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maxcode[i] = huffcode[j+bitcount];
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}
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if(mincode[i]!=-1)
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valptr[i] = (short) (valptr[i] - mincode[i]);
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bitcount += bits[i];
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}
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}
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/**
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* Generated from FIGURE C.3 - Generation of Order Codes and tables EHUFCO
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* and EHUFSI from the ISO DIS 10918-1. Requirements and Guidelines
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*/
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public void orderCodes(boolean isDC)
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{
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EHUFCO = new short[isDC ? 15 : 255];
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EHUFSI = new short[isDC ? 15 : 255];
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for (int p=0; p < lastk ; p++)
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{
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int i = huffval[p];
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if(i < 0 || i > EHUFCO.length || EHUFSI[i]!=0)
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System.err.println("Error, bad huffman table.");
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EHUFCO[i] = huffcode[p];
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EHUFSI[i] = huffsize[p];
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}
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}
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/**
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* Generated from FIGURE F.12 - Extending the sign bit of a decoded value in on
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* ISO DIS 10918-1. Requirements and Guidelines<p>
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*
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* @param diff TODO
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* @param t TODO
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* @return TODO
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*/
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public static int extend(int diff, int t)
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{
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int Vt = (int)Math.pow(2,(t-1));
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if(diff<Vt)
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{
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Vt=(-1 << t)+1;
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diff=diff+Vt;
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}
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return diff;
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}
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/**
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* Generated from FIGURE F.16 - Procedure for DECODE on
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* ISO DIS 10918-1. Requirements and Guidelines<p>
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*
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* This function takes in a dynamic amount of bits and using the Huffman
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* table returns information on how many bits must be read in to a byte in
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* order to reconstruct said byte.
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*
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* @param JPEGStream the bits of the data stream.
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*/
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public int decode(JPEGImageInputStream JPEGStream)
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throws IOException, JPEGException
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{
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int i=0;
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short code = (short) JPEGStream.readBits(1);
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while(code > maxcode[i])
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{
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i++;
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code <<= 1;
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code |= JPEGStream.readBits(1);
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}
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int val = huffval[code+(valptr[i])];
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if(val < 0)
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val = 256 + val;
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return val;
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}
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}
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