689c1910aa
sequences, I've created RTFFixerInputStream. It turns illegal hexadecimal escapes into Unicode escapes.
297 lines
12 KiB
Java
297 lines
12 KiB
Java
/*
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The contents of this file are subject to the THDL Open Community License
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Version 1.0 (the "License"); you may not use this file except in compliance
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with the License. You may obtain a copy of the License on the THDL web site
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(http://www.thdl.org/).
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Software distributed under the License is distributed on an "AS IS" basis,
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WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
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License for the specific terms governing rights and limitations under the
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License.
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The Initial Developer of this software is the Tibetan and Himalayan Digital
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Library (THDL). Portions created by the THDL are Copyright 2003 THDL.
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All Rights Reserved.
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Contributor(s): ______________________________________.
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*/
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package org.thdl.util;
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import org.thdl.util.ThdlDebug;
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import java.util.ArrayList;
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import java.io.IOException;
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import java.io.FilterInputStream;
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import java.io.BufferedInputStream;
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import java.io.InputStream;
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/** Provides an input stream that fixes an RTF input stream so that it
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no longer contains hexadecimal escapes that {@see
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javax.swing.text.rtf#RTFEditorKit} cannot understand. Instead,
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Unicode escapes (that can be understood) are used. This is almost
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as fast as possible.
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@author David Chandler */
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public class RTFFixerInputStream extends FilterInputStream {
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/** Holds onto the bytes we've read that we haven't yet passed
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along to the user. */
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private ArrayList ourBuffer = new ArrayList(21);
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/** if true, then all hexadecimal escapes are replaced; if false,
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then just the 32 "\\\'8X" and "\\\'9X" escapes are replaced. */
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private boolean replaceAllHexEscapes = false;
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/** 7, as in "\\u255 ?" (KEEP THIS IN SYNC WITH addASpace) */
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static final int bytesInNewEscape = 7;
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/** true if you want "\\u255 ?" instead of "\\u255?" (KEEP THIS IN SYNC WITH bytesInNewEscape) */
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private static final boolean addASpace = true;
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private boolean weSubstitutedAtLeastOnce = false;
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/** 4, as in "\\\'ff" */
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static final int bytesInOldEscape = 4;
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/** an instance field just to avoid needless heap allocation */
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private final byte readHelper[] = new byte[bytesInNewEscape];
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/** Constructs an RTFFixerInputStream that will fix in. No
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hexadecimal escapes will remain. */
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public RTFFixerInputStream(InputStream in) {
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// our read(..) methods may do multiple reads, so buffer this guy:
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super(new BufferedInputStream(in));
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replaceAllHexEscapes = true;
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}
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/** Constructs an RTFFixerInputStream that will fix in. No
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hexadecimal escapes will remain if replaceAllHexEscapes is
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true; only "\\\'8X" and "\\\'9X" will be replaced otherwise.
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(This is private, but you can make it public if you test it.) */
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private RTFFixerInputStream(InputStream in, boolean replaceAllHexEscapes) {
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super(in);
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this.replaceAllHexEscapes = replaceAllHexEscapes;
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}
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public int available() throws IOException {
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// We might have to hold on to "\\'9", so report 3 less than
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// the super says.
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int x = super.available();
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if (x > 3)
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return x - 3;
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else
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return 0;
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}
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/** I don't want to think about marking and resetting if I don't
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have to, so this stream doesn't support mark and reset.
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@return false
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*/
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public boolean markSupported() {
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return false;
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}
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/** Throws an exception. */
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public void reset() throws IOException {
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throw new IOException("RTFFixerInputStream does not support mark and reset");
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}
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/** Throws an exception. */
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public void mark(int r) {
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throw new Error("RTFFixerInputStream does not support mark and reset");
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}
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/** Throws an exception. */
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public long skip(long n) throws IOException {
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throw new IOException("RTFFixerInputStream does not support skipping. It could, but that's more work because you have to think about final bytes versus original bytes.");
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}
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public int read() throws IOException {
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if (ourBuffer.size() > 0) {
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int rv = ((Integer)ourBuffer.get(0)).intValue();
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ourBuffer.remove(0);
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return rv;
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}
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int ch1 = super.read();
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if (ch1 == (int)'\\') {
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// we might be staring at an escape sequence.
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readHelper[0] = (byte)ch1;
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int x = readAndConvertEscapeSequence(readHelper, 0, 1);
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int j = 0;
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while (x > 0) {
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ourBuffer.add(new Integer(readHelper[j++]));
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--x;
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}
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// Return ourBuffer's first element:
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return read();
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} else {
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return ch1;
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}
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}
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public int read(byte[] bb) throws IOException {
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return read(bb, 0, bb.length);
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}
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public int read(byte[] bb, int off, int len) throws IOException {
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if (ourBuffer.size() > 0) {
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// return as much as we can of this.
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int i;
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for (i = 0; (i < len) && (ourBuffer.size() > 0); i++) {
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bb[off + i] = (byte)((Integer)ourBuffer.get(0)).intValue();
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ourBuffer.remove(0);
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}
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return i;
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}
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int superRV = super.read(bb, off, len);
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ThdlDebug.verify(superRV == -1 || len == 0 || superRV > 0);
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if (superRV == -1 || superRV == 0)
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return superRV;
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byte temp[]
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= new byte[(superRV*bytesInNewEscape)/bytesInOldEscape + bytesInNewEscape + 10];
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// number of elements used in temp:
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int len_used = superRV;
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System.arraycopy(bb, off, temp, 0, superRV);
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// Now see if the last characters might be part of a hex
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// escape sequence by reading ahead enough to say one way or
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// the other. We do this before we replace the full hex
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// escape sequences so that we never have parts of a hex
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// escape sequence living in ourBuffer. If the last
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// characters might be, put them into temp. Eventually, we'll
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// take the part of temp that can't fit in bb and put it into
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// ourBuffer. We return as many bytes as super.read(..) did
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// so that we don't ever return 0.
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// Three cases: (1) \\'8 ends the writable space of bb
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// (2) \\' ends it
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// (3) \\ ends it
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for (int k = 3; k >= 1; k--) {
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if (len_used >= k) {
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if (temp[len_used - k] == '\\') {
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len_used += readAndConvertEscapeSequence(temp, len_used - k, k) - k;
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}
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}
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}
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// Now replace any full escape sequences in temp.
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for (int i = 0; i < len_used - (bytesInOldEscape - 1); i++) {
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// Replace the escape sequence beginning at i, if there is
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// one we care about beginning there.
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if (temp[i] == '\\' && temp[i+1] == '\'') {
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for (int h = 0; h < bytesInOldEscape; h++) {
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readHelper[h] = temp[i + h];
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}
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int y = readAndConvertEscapeSequence(readHelper, 0, bytesInOldEscape);
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ThdlDebug.verify(y == bytesInOldEscape
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|| y == bytesInNewEscape);
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if (y == bytesInNewEscape) {
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len_used += (bytesInNewEscape - bytesInOldEscape);
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// Shift everything past the old escape down by one:
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System.arraycopy(temp,
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i+bytesInOldEscape,
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temp,
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i+bytesInNewEscape,
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len_used - (i+bytesInOldEscape));
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System.arraycopy(readHelper,
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0,
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temp,
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i,
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bytesInNewEscape);
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}
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}
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}
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// Copy temp into bb, with overflow going into ourBuffer:
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System.arraycopy(temp,
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0,
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bb,
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off,
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superRV);
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int g = 0;
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ThdlDebug.verify(ourBuffer.size() == 0);
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while (len_used-- > superRV) {
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ourBuffer.add(new Integer(temp[superRV + g++]));
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}
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return superRV;
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}
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/** Given that old[offset] through old[offset+num_valid-1]
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contain valid characters, the first being a backslash,
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this routine reads as much as is needed from in to
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determine whether we're looking at a hex escape we care
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about. If we are, then old[offset] through old[offset+4]
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will hold it. old better be able to hold up to 4 more
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it's currently using, or you'll get an
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ArrayBoundsException.
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@return the number now valid in old on or after offset */
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private int readAndConvertEscapeSequence(byte old[], int offset,
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int num_valid)
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throws IOException {
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ThdlDebug.verify(old[offset] == '\\');
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while (num_valid < 4) {
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int x = super.read();
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if (x == -1)
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return num_valid;
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old[offset+num_valid++] = (byte)x;
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}
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if (old[offset+1] != (int)'\'') {
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// This is not a hex escape we care about.
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return num_valid;
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}
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if (replaceAllHexEscapes) {
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if (old[offset+2] != (int)'8'
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&& old[offset+2] != (int)'9') {
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// This is not a hex escape we care about.
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return num_valid;
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}
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} else {
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if (!isHexChar(old[offset+2])) {
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// This is not a hex escape we care about.
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return num_valid;
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}
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}
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if (!isHexChar(old[offset+3])) {
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// This is not a hex escape we care about.
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return num_valid;
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}
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// We got here, so it's a hex escape we care about.
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weSubstitutedAtLeastOnce = true;
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// Go from \\' to \\u:
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old[offset+1] = 'u';
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int decimalValue = getHexValue(old[offset+2])*16 + getHexValue(old[offset+3]);
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// We'll use \\uXXX, i.e. we'll always use three digits.
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// \\u156, \\u200, \\u049, \\u001, e.g.
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int hundreds, tens, ones;
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char saved2 = (char)old[offset+2];
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char saved3 = (char)old[offset+3];
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old[offset+2] = (byte)('0' + (hundreds = (decimalValue / 100))); // replace
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old[offset+3] = (byte)('0' + (tens = ((decimalValue - 100*hundreds) / 10))); // replace
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old[offset+4] = (byte)('0' + (ones = (decimalValue - 100*hundreds - 10*tens))); ++num_valid;
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if (addASpace)
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old[offset+5] = (byte)' '; ++num_valid;
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old[offset+6] = (byte)'?'; ++num_valid;
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return num_valid;
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}
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/** Returns true iff (char)e is one of
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[0123456789abcdefABCDEF]. */
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private static final boolean isHexChar(int e) {
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return (getHexValue(e) != -1);
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}
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/** Returns the decimal value of (char)e, interpreting (char)e as
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a hex character. Returns -1 if e is not a hex character. */
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private static final int getHexValue(int e) {
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if ((e >= (int)'0' && e <= (int)'9'))
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return e - (int)'0';
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if ((e >= (int)'a' && e <= (int)'f'))
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return 10 + e - (int)'a';
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if ((e >= (int)'A' && e <= (int)'F'))
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return 10 + e - (int)'A';
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return -1;
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}
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/** Returns true if and only if at least one substitution was
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performed. Returns false if none have been performed. */
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public boolean performedSubstitutions() {
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return weSubstitutedAtLeastOnce;
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}
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}
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