Initial revision

From-SVN: r102074

1 files changed, 696 insertions, 0 deletions

diff --git a/libjava/classpath/java/util/zip/DeflaterEngine.java b/libjava/classpath/java/util/zip/DeflaterEngine.java
new file mode 100644
index 0000000..3eea7c2
--- /dev/null
+++ b/libjava/classpath/java/util/zip/DeflaterEngine.java
@@ -0,0 +1,696 @@
+/* DeflaterEngine.java --
+   Copyright (C) 2001, 2004  Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Classpath 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 for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING.  If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library.  Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module.  An independent module is a module which is not derived from
+or based on this library.  If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so.  If you do not wish to do so, delete this
+exception statement from your version. */
+
+package java.util.zip;
+
+class DeflaterEngine implements DeflaterConstants
+{
+  private static final int TOO_FAR = 4096;
+
+  private int ins_h;
+
+  /**
+   * Hashtable, hashing three characters to an index for window, so
+   * that window[index]..window[index+2] have this hash code.  
+   * Note that the array should really be unsigned short, so you need
+   * to and the values with 0xffff.
+   */
+  private short[] head;
+
+  /**
+   * prev[index & WMASK] points to the previous index that has the
+   * same hash code as the string starting at index.  This way 
+   * entries with the same hash code are in a linked list.
+   * Note that the array should really be unsigned short, so you need
+   * to and the values with 0xffff.
+   */
+  private short[] prev;
+
+  private int matchStart, matchLen;
+  private boolean prevAvailable;
+  private int blockStart;
+
+  /**
+   * strstart points to the current character in window.
+   */
+  private int strstart;
+
+  /**
+   * lookahead is the number of characters starting at strstart in
+   * window that are valid.
+   * So window[strstart] until window[strstart+lookahead-1] are valid
+   * characters.
+   */
+  private int lookahead;
+
+  /**
+   * This array contains the part of the uncompressed stream that 
+   * is of relevance.  The current character is indexed by strstart.
+   */
+  private byte[] window;
+
+  private int strategy, max_chain, max_lazy, niceLength, goodLength;
+
+  /** The current compression function. */
+  private int comprFunc;
+
+  /** The input data for compression. */
+  private byte[] inputBuf;
+
+  /** The total bytes of input read. */
+  private int totalIn;
+
+  /** The offset into inputBuf, where input data starts. */
+  private int inputOff;
+
+  /** The end offset of the input data. */
+  private int inputEnd;
+
+  private DeflaterPending pending;
+  private DeflaterHuffman huffman;
+
+  /** The adler checksum */
+  private Adler32 adler;
+
+  /* DEFLATE ALGORITHM:
+   *
+   * The uncompressed stream is inserted into the window array.  When
+   * the window array is full the first half is thrown away and the
+   * second half is copied to the beginning.
+   *
+   * The head array is a hash table.  Three characters build a hash value
+   * and they the value points to the corresponding index in window of 
+   * the last string with this hash.  The prev array implements a
+   * linked list of matches with the same hash: prev[index & WMASK] points
+   * to the previous index with the same hash.
+   * 
+   * 
+   */
+
+
+  DeflaterEngine(DeflaterPending pending) {
+    this.pending = pending;
+    huffman = new DeflaterHuffman(pending);
+    adler = new Adler32();
+
+    window = new byte[2*WSIZE];
+    head   = new short[HASH_SIZE];
+    prev   = new short[WSIZE];
+
+    /* We start at index 1, to avoid a implementation deficiency, that
+     * we cannot build a repeat pattern at index 0.
+     */
+    blockStart = strstart = 1;
+  }
+
+  public void reset()
+  {
+    huffman.reset();
+    adler.reset();
+    blockStart = strstart = 1;
+    lookahead = 0;
+    totalIn = 0;
+    prevAvailable = false;
+    matchLen = MIN_MATCH - 1;
+    for (int i = 0; i < HASH_SIZE; i++)
+      head[i] = 0;
+    for (int i = 0; i < WSIZE; i++)
+      prev[i] = 0;
+  }
+
+  public final void resetAdler()
+  {
+    adler.reset();
+  }
+
+  public final int getAdler()
+  {
+    int chksum = (int) adler.getValue();
+    return chksum;
+  }
+
+  public final int getTotalIn()
+  {
+    return totalIn;
+  }
+
+  public final void setStrategy(int strat)
+  {
+    strategy = strat;
+  }
+
+  public void setLevel(int lvl)
+  {
+    goodLength = DeflaterConstants.GOOD_LENGTH[lvl];
+    max_lazy    = DeflaterConstants.MAX_LAZY[lvl];
+    niceLength = DeflaterConstants.NICE_LENGTH[lvl];
+    max_chain   = DeflaterConstants.MAX_CHAIN[lvl];
+
+    if (DeflaterConstants.COMPR_FUNC[lvl] != comprFunc) 
+      {
+	if (DeflaterConstants.DEBUGGING)
+	  System.err.println("Change from "+comprFunc +" to "
+			     + DeflaterConstants.COMPR_FUNC[lvl]);
+	switch (comprFunc)
+	  {
+	  case DEFLATE_STORED:
+	    if (strstart > blockStart)
+	      {
+		huffman.flushStoredBlock(window, blockStart, 
+					 strstart - blockStart, false);
+		blockStart = strstart;
+	      }
+	    updateHash();
+	    break;
+	  case DEFLATE_FAST:
+	    if (strstart > blockStart)
+	      {
+		huffman.flushBlock(window, blockStart, strstart - blockStart,
+				   false);
+		blockStart = strstart;
+	      }
+	    break;
+	  case DEFLATE_SLOW:
+	    if (prevAvailable)
+	      huffman.tallyLit(window[strstart-1] & 0xff);
+	    if (strstart > blockStart)
+	      {
+		huffman.flushBlock(window, blockStart, strstart - blockStart,
+				   false);
+		blockStart = strstart;
+	      }
+	    prevAvailable = false;
+	    matchLen = MIN_MATCH - 1;
+	    break;
+	  }
+	comprFunc = COMPR_FUNC[lvl];
+      }
+  }
+
+  private void updateHash() {
+    if (DEBUGGING)
+      System.err.println("updateHash: "+strstart);
+    ins_h = (window[strstart] << HASH_SHIFT) ^ window[strstart + 1];
+  }    
+
+  /**
+   * Inserts the current string in the head hash and returns the previous
+   * value for this hash.
+   */
+  private int insertString() {
+    short match;
+    int hash = ((ins_h << HASH_SHIFT) ^ window[strstart + (MIN_MATCH -1)])
+      & HASH_MASK;
+
+    if (DEBUGGING)
+      {
+	if (hash != (((window[strstart] << (2*HASH_SHIFT))
+		      ^ (window[strstart + 1] << HASH_SHIFT)
+		      ^ (window[strstart + 2])) & HASH_MASK))
+	  throw new InternalError("hash inconsistent: "+hash+"/"
+				  +window[strstart]+","
+				  +window[strstart+1]+","
+				  +window[strstart+2]+","+HASH_SHIFT);
+      }
+
+    prev[strstart & WMASK] = match = head[hash];
+    head[hash] = (short) strstart;
+    ins_h = hash;
+    return match & 0xffff;
+  }
+
+  private void slideWindow()
+  {
+    System.arraycopy(window, WSIZE, window, 0, WSIZE);
+    matchStart -= WSIZE;
+    strstart -= WSIZE;
+    blockStart -= WSIZE;
+    
+    /* Slide the hash table (could be avoided with 32 bit values
+     * at the expense of memory usage).
+     */
+    for (int i = 0; i < HASH_SIZE; i++) 
+      {
+	int m = head[i] & 0xffff;
+	head[i] = m >= WSIZE ? (short) (m - WSIZE) : 0;
+      }
+
+    /* Slide the prev table.
+     */
+    for (int i = 0; i < WSIZE; i++) 
+      {
+	int m = prev[i] & 0xffff;
+	prev[i] = m >= WSIZE ? (short) (m - WSIZE) : 0;
+      }
+  }
+
+  /**
+   * Fill the window when the lookahead becomes insufficient.
+   * Updates strstart and lookahead.
+   *
+   * OUT assertions: strstart + lookahead <= 2*WSIZE
+   *    lookahead >= MIN_LOOKAHEAD or inputOff == inputEnd
+   */
+  private void fillWindow()
+  {
+    /* If the window is almost full and there is insufficient lookahead,
+     * move the upper half to the lower one to make room in the upper half.
+     */
+    if (strstart >= WSIZE + MAX_DIST)
+      slideWindow();
+
+    /* If there is not enough lookahead, but still some input left,
+     * read in the input
+     */
+    while (lookahead < DeflaterConstants.MIN_LOOKAHEAD && inputOff < inputEnd)
+      {
+	int more = 2*WSIZE - lookahead - strstart;
+	
+	if (more > inputEnd - inputOff)
+	  more = inputEnd - inputOff;
+
+	System.arraycopy(inputBuf, inputOff, 
+			 window, strstart + lookahead, more);
+	adler.update(inputBuf, inputOff, more);
+	inputOff += more;
+	totalIn  += more;
+	lookahead += more;
+      }
+
+    if (lookahead >= MIN_MATCH) 
+      updateHash();
+  }
+
+  /**
+   * Find the best (longest) string in the window matching the 
+   * string starting at strstart.
+   *
+   * Preconditions:
+   *    strstart + MAX_MATCH <= window.length.
+   *    
+   *
+   * @param curMatch
+   */
+  private boolean findLongestMatch(int curMatch) {
+    int chainLength = this.max_chain;
+    int niceLength = this.niceLength;
+    short[] prev = this.prev;
+    int scan  = this.strstart;
+    int match;
+    int best_end = this.strstart + matchLen;
+    int best_len = Math.max(matchLen, MIN_MATCH - 1);
+    
+    int limit = Math.max(strstart - MAX_DIST, 0);
+
+    int strend = scan + MAX_MATCH - 1;
+    byte scan_end1 = window[best_end - 1];
+    byte scan_end  = window[best_end];
+
+    /* Do not waste too much time if we already have a good match: */
+    if (best_len >= this.goodLength)
+      chainLength >>= 2;
+
+    /* Do not look for matches beyond the end of the input. This is necessary
+     * to make deflate deterministic.
+     */
+    if (niceLength > lookahead)
+      niceLength = lookahead;
+
+    if (DeflaterConstants.DEBUGGING 
+	&& strstart > 2*WSIZE - MIN_LOOKAHEAD)
+      throw new InternalError("need lookahead");
+    
+    do {
+      if (DeflaterConstants.DEBUGGING && curMatch >= strstart)
+	throw new InternalError("future match");
+      if (window[curMatch + best_len] != scan_end
+	  || window[curMatch + best_len - 1] != scan_end1
+	  || window[curMatch] != window[scan]
+	  || window[curMatch+1] != window[scan + 1])
+	continue;
+
+      match = curMatch + 2;      
+      scan += 2;
+
+      /* We check for insufficient lookahead only every 8th comparison;
+       * the 256th check will be made at strstart+258.
+       */
+      while (window[++scan] == window[++match]
+	     && window[++scan] == window[++match]
+	     && window[++scan] == window[++match]
+	     && window[++scan] == window[++match]
+	     && window[++scan] == window[++match]
+	     && window[++scan] == window[++match]
+	     && window[++scan] == window[++match]
+	     && window[++scan] == window[++match]
+	     && scan < strend);
+
+      if (scan > best_end) {
+//  	if (DeflaterConstants.DEBUGGING && ins_h == 0)
+//  	  System.err.println("Found match: "+curMatch+"-"+(scan-strstart));
+	matchStart = curMatch;
+	best_end = scan;
+	best_len = scan - strstart;
+	if (best_len >= niceLength)
+	  break;
+
+	scan_end1  = window[best_end-1];
+	scan_end   = window[best_end];
+      }
+      scan = strstart;
+    } while ((curMatch = (prev[curMatch & WMASK] & 0xffff)) > limit
+	     && --chainLength != 0);
+
+    matchLen = Math.min(best_len, lookahead);
+    return matchLen >= MIN_MATCH;
+  }
+
+  void setDictionary(byte[] buffer, int offset, int length) {
+    if (DeflaterConstants.DEBUGGING && strstart != 1)
+      throw new IllegalStateException("strstart not 1");
+    adler.update(buffer, offset, length);
+    if (length < MIN_MATCH)
+      return;
+    if (length > MAX_DIST) {
+      offset += length - MAX_DIST;
+      length = MAX_DIST;
+    }
+
+    System.arraycopy(buffer, offset, window, strstart, length);
+
+    updateHash();
+    length--;
+    while (--length > 0)
+      {
+	insertString();
+	strstart++;
+      }
+    strstart += 2;
+    blockStart = strstart;
+  }    
+    
+  private boolean deflateStored(boolean flush, boolean finish)
+  {
+    if (!flush && lookahead == 0)
+      return false;
+
+    strstart += lookahead;
+    lookahead = 0;
+
+    int storedLen = strstart - blockStart;
+
+    if ((storedLen >= DeflaterConstants.MAX_BLOCK_SIZE) 
+	/* Block is full */
+	|| (blockStart < WSIZE && storedLen >= MAX_DIST)
+	/* Block may move out of window */
+	|| flush)
+      {
+	boolean lastBlock = finish;
+	if (storedLen > DeflaterConstants.MAX_BLOCK_SIZE)
+	  {
+	    storedLen = DeflaterConstants.MAX_BLOCK_SIZE;
+	    lastBlock = false;
+	  }
+
+	if (DeflaterConstants.DEBUGGING)
+	  System.err.println("storedBlock["+storedLen+","+lastBlock+"]");
+
+	huffman.flushStoredBlock(window, blockStart, storedLen, lastBlock);
+	blockStart += storedLen;
+	return !lastBlock;
+      }
+    return true;
+  }
+
+  private boolean deflateFast(boolean flush, boolean finish)
+  {
+    if (lookahead < MIN_LOOKAHEAD && !flush)
+      return false;
+
+    while (lookahead >= MIN_LOOKAHEAD || flush)
+      {
+	if (lookahead == 0)
+	  {
+	    /* We are flushing everything */
+	    huffman.flushBlock(window, blockStart, strstart - blockStart,
+			       finish);
+	    blockStart = strstart;
+	    return false;
+	  }
+
+	if (strstart > 2 * WSIZE - MIN_LOOKAHEAD)
+	  {
+	    /* slide window, as findLongestMatch need this.
+	     * This should only happen when flushing and the window
+	     * is almost full.
+	     */
+	    slideWindow();
+	  }
+
+	int hashHead;
+	if (lookahead >= MIN_MATCH 
+	    && (hashHead = insertString()) != 0
+	    && strategy != Deflater.HUFFMAN_ONLY
+	    && strstart - hashHead <= MAX_DIST
+	    && findLongestMatch(hashHead))
+	  {
+	    /* longestMatch sets matchStart and matchLen */
+	    if (DeflaterConstants.DEBUGGING)
+	      {
+		for (int i = 0 ; i < matchLen; i++)
+		  {
+		    if (window[strstart+i] != window[matchStart + i])
+		      throw new InternalError();
+		  }
+	      }
+	    huffman.tallyDist(strstart - matchStart, matchLen);
+	    
+	    lookahead -= matchLen;
+	    if (matchLen <= max_lazy && lookahead >= MIN_MATCH)
+	      {
+		while (--matchLen > 0)
+		  {
+		    strstart++;
+		    insertString();
+		  }
+		strstart++;
+	      }
+	    else
+	      {
+		strstart += matchLen;
+		if (lookahead >= MIN_MATCH - 1)
+		  updateHash();
+	      }
+	    matchLen = MIN_MATCH - 1;
+	    continue;
+	  }
+	else
+	  {
+	    /* No match found */
+	    huffman.tallyLit(window[strstart] & 0xff);
+	    strstart++;
+	    lookahead--;
+	  }
+
+	if (huffman.isFull())
+	  {
+	    boolean lastBlock = finish && lookahead == 0;
+	    huffman.flushBlock(window, blockStart, strstart - blockStart,
+			       lastBlock);
+	    blockStart = strstart;
+	    return !lastBlock;
+	  }
+      }
+    return true;
+  }
+
+  private boolean deflateSlow(boolean flush, boolean finish)
+  {
+    if (lookahead < MIN_LOOKAHEAD && !flush)
+      return false;
+
+    while (lookahead >= MIN_LOOKAHEAD || flush)
+      {
+	if (lookahead == 0)
+	  {
+	    if (prevAvailable)
+	      huffman.tallyLit(window[strstart-1] & 0xff);
+	    prevAvailable = false;
+
+	    /* We are flushing everything */
+	    if (DeflaterConstants.DEBUGGING && !flush)
+	      throw new InternalError("Not flushing, but no lookahead");
+	    huffman.flushBlock(window, blockStart, strstart - blockStart,
+			       finish);
+	    blockStart = strstart;
+	    return false;
+	  }
+
+	if (strstart >= 2 * WSIZE - MIN_LOOKAHEAD)
+	  {
+	    /* slide window, as findLongestMatch need this.
+	     * This should only happen when flushing and the window
+	     * is almost full.
+	     */
+	    slideWindow();
+	  }
+
+	int prevMatch = matchStart;
+	int prevLen = matchLen;
+	if (lookahead >= MIN_MATCH)
+	  {
+	    int hashHead = insertString();
+	    if (strategy != Deflater.HUFFMAN_ONLY
+		&& hashHead != 0 && strstart - hashHead <= MAX_DIST
+		&& findLongestMatch(hashHead))
+	      {
+		/* longestMatch sets matchStart and matchLen */
+		
+		/* Discard match if too small and too far away */
+		if (matchLen <= 5
+		    && (strategy == Deflater.FILTERED
+			|| (matchLen == MIN_MATCH
+			    && strstart - matchStart > TOO_FAR))) {
+		  matchLen = MIN_MATCH - 1;
+		}
+	      }
+	  }
+	
+	/* previous match was better */
+	if (prevLen >= MIN_MATCH && matchLen <= prevLen)
+	  {
+	    if (DeflaterConstants.DEBUGGING)
+	      {
+		for (int i = 0 ; i < matchLen; i++)
+		  {
+		    if (window[strstart-1+i] != window[prevMatch + i])
+		      throw new InternalError();
+		  }
+	      }
+	    huffman.tallyDist(strstart - 1 - prevMatch, prevLen);
+	    prevLen -= 2;
+	    do 
+	      {
+		strstart++;
+		lookahead--;
+		if (lookahead >= MIN_MATCH)
+		  insertString();
+	      }
+	    while (--prevLen > 0);
+	    strstart ++;
+	    lookahead--;
+	    prevAvailable = false;
+	    matchLen = MIN_MATCH - 1;
+	  }
+	else
+	  {
+	    if (prevAvailable)
+	      huffman.tallyLit(window[strstart-1] & 0xff);
+	    prevAvailable = true;
+	    strstart++;
+	    lookahead--;
+	  }
+
+	if (huffman.isFull())
+	  {
+	    int len = strstart - blockStart;
+	    if (prevAvailable)
+	      len--;
+	    boolean lastBlock = (finish && lookahead == 0 && !prevAvailable);
+	    huffman.flushBlock(window, blockStart, len, lastBlock);
+	    blockStart += len;
+	    return !lastBlock;
+	  }
+      }
+    return true;
+  } 
+
+  public boolean deflate(boolean flush, boolean finish) 
+  {
+    boolean progress;
+    do
+      {
+	fillWindow();
+	boolean canFlush = flush && inputOff == inputEnd;
+	if (DeflaterConstants.DEBUGGING)
+	  System.err.println("window: ["+blockStart+","+strstart+","
+			     +lookahead+"], "+comprFunc+","+canFlush);
+	switch (comprFunc)
+	  {
+	  case DEFLATE_STORED:
+	    progress = deflateStored(canFlush, finish);
+	    break;
+	  case DEFLATE_FAST:
+	    progress = deflateFast(canFlush, finish);
+	    break;
+	  case DEFLATE_SLOW:
+	    progress = deflateSlow(canFlush, finish);
+	    break;
+	  default:
+	    throw new InternalError();
+	  }
+      }
+    while (pending.isFlushed()  /* repeat while we have no pending output */
+	   && progress);        /* and progress was made */
+
+    return progress;
+  }
+
+  public void setInput(byte[] buf, int off, int len)
+  {
+    if (inputOff < inputEnd)
+      throw new IllegalStateException
+	("Old input was not completely processed");
+
+    int end = off + len;
+
+    /* We want to throw an ArrayIndexOutOfBoundsException early.  The
+     * check is very tricky: it also handles integer wrap around.  
+     */
+    if (0 > off || off > end || end > buf.length)
+      throw new ArrayIndexOutOfBoundsException();
+
+    inputBuf = buf;
+    inputOff = off;
+    inputEnd = end;
+  }
+
+  public final boolean needsInput()
+  {
+    return inputEnd == inputOff;
+  }
+}