diff --git a/lib/zlib/deflate.js b/lib/zlib/deflate.js
index c3c0f58..f2e0e8e 100644
--- a/lib/zlib/deflate.js
+++ b/lib/zlib/deflate.js
@@ -631,28 +631,323 @@ function deflate_fast(s, flush) {
  * evaluation for matches: a match is finally adopted only if there is
  * no better match at the next window position.
  */
-function deflate_slow(/*s, flush*/) {
+function deflate_slow(s, flush) {
+  var hash_head;          /* head of hash chain */
+  var bflush;              /* set if current block must be flushed */
 
+  var max_insert;
+
+  /* Process the input block. */
+  for (;;) {
+    /* Make sure that we always have enough lookahead, except
+     * at the end of the input file. We need MAX_MATCH bytes
+     * for the next match, plus MIN_MATCH bytes to insert the
+     * string following the next match.
+     */
+    if (s.lookahead < MIN_LOOKAHEAD) {
+      fill_window(s);
+      if (s.lookahead < MIN_LOOKAHEAD && flush === c.Z_NO_FLUSH) {
+        return BS_NEED_MORE;
+      }
+      if (s.lookahead === 0) { break; } /* flush the current block */
+    }
+
+    /* Insert the string window[strstart .. strstart+2] in the
+     * dictionary, and set hash_head to the head of the hash chain:
+     */
+    hash_head = NIL;
+    if (s.lookahead >= MIN_MATCH) {
+      /*** INSERT_STRING(s, s.strstart, hash_head); ***/
+      s.ins_h = ((s.ins_h << s.hash_shift) ^ s.window[s.strstart + MIN_MATCH - 1]) & s.hash_mask;
+      hash_head = (s.head[s.ins_h] & 0xffff);
+      s.prev[s.strstart & s.w_mask] = s.head[s.ins_h];
+      s.head[s.ins_h] = s.strstart;
+      /***/
+    }
+
+    /* Find the longest match, discarding those <= prev_length.
+     */
+    s.prev_length = s.match_length;
+    s.prev_match = s.match_start;
+    s.match_length = MIN_MATCH-1;
+
+    if (hash_head !== NIL && s.prev_length < s.max_lazy_match &&
+        s.strstart - hash_head <= (s.w_size-MIN_LOOKAHEAD)/*MAX_DIST(s)*/) {
+      /* To simplify the code, we prevent matches with the string
+       * of window index 0 (in particular we have to avoid a match
+       * of the string with itself at the start of the input file).
+       */
+      s.match_length = longest_match(s, hash_head);
+      /* longest_match() sets match_start */
+
+      if (s.match_length <= 5 &&
+         (s.strategy === c.Z_FILTERED || (s.match_length === MIN_MATCH && s.strstart - s.match_start > 4096/*TOO_FAR*/))) {
+
+        /* If prev_match is also MIN_MATCH, match_start is garbage
+         * but we will ignore the current match anyway.
+         */
+        s.match_length = MIN_MATCH-1;
+      }
+    }
+    /* If there was a match at the previous step and the current
+     * match is not better, output the previous match:
+     */
+    if (s.prev_length >= MIN_MATCH && s.match_length <= s.prev_length) {
+      max_insert = s.strstart + s.lookahead - MIN_MATCH;
+      /* Do not insert strings in hash table beyond this. */
+
+      //check_match(s, s.strstart-1, s.prev_match, s.prev_length);
+
+      /***_tr_tally_dist(s, s.strstart - 1 - s.prev_match,
+                     s.prev_length - MIN_MATCH, bflush);***/
+      bflush = trees._tr_tally(s, s.strstart - 1- s.match_start, s.prev_length - MIN_MATCH);
+
+      /* Insert in hash table all strings up to the end of the match.
+       * strstart-1 and strstart are already inserted. If there is not
+       * enough lookahead, the last two strings are not inserted in
+       * the hash table.
+       */
+      s.lookahead -= s.prev_length-1;
+      s.prev_length -= 2;
+      do {
+        if (++s.strstart <= max_insert) {
+          /*** INSERT_STRING(s, s.strstart, hash_head); ***/
+          s.ins_h = ((s.ins_h << s.hash_shift) ^ s.window[s.strstart + MIN_MATCH - 1]) & s.hash_mask;
+          hash_head = (s.head[s.ins_h] & 0xffff);
+          s.prev[s.strstart & s.w_mask] = s.head[s.ins_h];
+          s.head[s.ins_h] = s.strstart;
+          /***/
+        }
+      } while (--s.prev_length !== 0);
+      s.match_available = 0;
+      s.match_length = MIN_MATCH-1;
+      s.strstart++;
+
+      if (bflush) {
+        /*** FLUSH_BLOCK(s, 0); ***/
+        flush_block_only(s, false);
+        if (s.strm.avail_out === 0) {
+          return BS_NEED_MORE;
+        }
+        /***/
+      }
+
+    } else if (s.match_available) {
+      /* If there was no match at the previous position, output a
+       * single literal. If there was a match but the current match
+       * is longer, truncate the previous match to a single literal.
+       */
+      //Tracevv((stderr,"%c", s->window[s->strstart-1]));
+      /*** _tr_tally_lit(s, s.window[s.strstart-1], bflush); ***/
+      bflush = trees._tr_tally(s, 0, s.window[s.strstart-1]);
+
+      if (bflush) {
+        /*** FLUSH_BLOCK(s, 0); ***/
+        flush_block_only(s, false);
+        if (s.strm.avail_out === 0) {
+          return BS_NEED_MORE;
+        }
+        /***/
+      }
+      s.strstart++;
+      s.lookahead--;
+      if (s.strm.avail_out === 0) {
+        return BS_NEED_MORE;
+      }
+    } else {
+      /* There is no previous match to compare with, wait for
+       * the next step to decide.
+       */
+      s.match_available = 1;
+      s.strstart++;
+      s.lookahead--;
+    }
+  }
+  //Assert (flush != Z_NO_FLUSH, "no flush?");
+  if (s.match_available) {
+    //Tracevv((stderr,"%c", s->window[s->strstart-1]));
+    /*** _tr_tally_lit(s, s.window[s.strstart-1], bflush); ***/
+    bflush = trees._tr_tally(s, 0, s.window[s.strstart-1]);
+
+    s.match_available = 0;
+  }
+  s.insert = s.strstart < MIN_MATCH-1 ? s.strstart : MIN_MATCH-1;
+  if (flush === c.Z_FINISH) {
+    /*** FLUSH_BLOCK(s, 1); ***/
+    flush_block_only(s, true);
+    if (s.strm.avail_out === 0) {
+      return BS_FINISH_STARTED;
+    }
+    /***/
+    return BS_FINISH_DONE;
+  }
+  if (s.last_lit) {
+    /*** FLUSH_BLOCK(s, 0); ***/
+    flush_block_only(s, false);
+    if (s.strm.avail_out === 0) {
+      return BS_NEED_MORE;
+    }
+    /***/
+  }
+
+  return BS_BLOCK_DONE;
 }
 
+
 /* ===========================================================================
  * For Z_RLE, simply look for runs of bytes, generate matches only of distance
  * one.  Do not maintain a hash table.  (It will be regenerated if this run of
  * deflate switches away from Z_RLE.)
  */
-function deflate_rle(/*s, flush*/) {
+function deflate_rle(s, flush) {
+  var bflush;            /* set if current block must be flushed */
+  var prev;              /* byte at distance one to match */
+  var scan, strend;      /* scan goes up to strend for length of run */
 
+  var _win = s.window;
+
+  for (;;) {
+    /* Make sure that we always have enough lookahead, except
+     * at the end of the input file. We need MAX_MATCH bytes
+     * for the longest run, plus one for the unrolled loop.
+     */
+    if (s.lookahead <= MAX_MATCH) {
+      fill_window(s);
+      if (s.lookahead <= MAX_MATCH && flush === c.Z_NO_FLUSH) {
+        return BS_NEED_MORE;
+      }
+      if (s.lookahead === 0) { break; } /* flush the current block */
+    }
+
+    /* See how many times the previous byte repeats */
+    s.match_length = 0;
+    if (s.lookahead >= MIN_MATCH && s.strstart > 0) {
+      scan = s.strstart - 1;
+      prev = _win[scan];
+      if (prev === _win[++scan] && prev === _win[++scan] && prev === _win[++scan]) {
+        strend = s.strstart + MAX_MATCH;
+        do {
+          /*jshint noempty:false*/
+        } while (prev === _win[++scan] && prev === _win[++scan] &&
+                 prev === _win[++scan] && prev === _win[++scan] &&
+                 prev === _win[++scan] && prev === _win[++scan] &&
+                 prev === _win[++scan] && prev === _win[++scan] &&
+                 scan < strend);
+        s.match_length = MAX_MATCH - (strend - scan);
+        if (s.match_length > s.lookahead) {
+          s.match_length = s.lookahead;
+        }
+      }
+      //Assert(scan <= s->window+(uInt)(s->window_size-1), "wild scan");
+    }
+
+    /* Emit match if have run of MIN_MATCH or longer, else emit literal */
+    if (s.match_length >= MIN_MATCH) {
+      //check_match(s, s.strstart, s.strstart - 1, s.match_length);
+
+      /*** _tr_tally_dist(s, 1, s.match_length - MIN_MATCH, bflush); ***/
+      bflush = trees._tr_tally(s, 1, s.match_length - MIN_MATCH);
+
+      s.lookahead -= s.match_length;
+
+      s.lookahead -= s.match_length;
+      s.strstart += s.match_length;
+      s.match_length = 0;
+    } else {
+      /* No match, output a literal byte */
+      //Tracevv((stderr,"%c", s->window[s->strstart]));
+      /*** _tr_tally_lit(s, s.window[s.strstart], bflush); ***/
+      bflush = trees._tr_tally(s, 0, s.window[s.strstart]);
+
+      s.lookahead--;
+      s.strstart++;
+    }
+    if (bflush) {
+      /*** FLUSH_BLOCK(s, 0); ***/
+      flush_block_only(s, false);
+      if (s.strm.avail_out === 0) {
+        return BS_NEED_MORE;
+      }
+      /***/
+    }
+  }
+  s.insert = 0;
+  if (flush === c.Z_FINISH) {
+    /*** FLUSH_BLOCK(s, 1); ***/
+    flush_block_only(s, true);
+    if (s.strm.avail_out === 0) {
+      return BS_FINISH_STARTED;
+    }
+    /***/
+    return BS_FINISH_DONE;
+  }
+  if (s.last_lit) {
+    /*** FLUSH_BLOCK(s, 0); ***/
+    flush_block_only(s, false);
+    if (s.strm.avail_out === 0) {
+      return BS_NEED_MORE;
+    }
+    /***/
+  }
+  return BS_BLOCK_DONE;
 }
 
 /* ===========================================================================
  * For Z_HUFFMAN_ONLY, do not look for matches.  Do not maintain a hash table.
  * (It will be regenerated if this run of deflate switches away from Huffman.)
  */
-function deflate_huff(/*s, flush*/) {
+function deflate_huff(s, flush) {
+  var bflush;             /* set if current block must be flushed */
 
+  for (;;) {
+    /* Make sure that we have a literal to write. */
+    if (s.lookahead === 0) {
+      fill_window(s);
+      if (s.lookahead === 0) {
+        if (flush === c.Z_NO_FLUSH) {
+          return BS_NEED_MORE;
+        }
+        break;      /* flush the current block */
+      }
+    }
+
+    /* Output a literal byte */
+    s.match_length = 0;
+    //Tracevv((stderr,"%c", s->window[s->strstart]));
+    /*** _tr_tally_lit(s, s.window[s.strstart], bflush); ***/
+    bflush = trees._tr_tally(s, 0, s.window[s.strstart]);
+    s.lookahead--;
+    s.strstart++;
+    if (bflush) {
+      /*** FLUSH_BLOCK(s, 0); ***/
+      flush_block_only(s, false);
+      if (s.strm.avail_out === 0) {
+        return BS_NEED_MORE;
+      }
+      /***/
+    }
+  }
+  s.insert = 0;
+  if (flush === c.Z_FINISH) {
+    /*** FLUSH_BLOCK(s, 1); ***/
+    flush_block_only(s, true);
+    if (s.strm.avail_out === 0) {
+      return BS_FINISH_STARTED;
+    }
+    /***/
+    return BS_FINISH_DONE;
+  }
+  if (s.last_lit) {
+    /*** FLUSH_BLOCK(s, 0); ***/
+    flush_block_only(s, false);
+    if (s.strm.avail_out === 0) {
+      return BS_NEED_MORE;
+    }
+    /***/
+  }
+  return BS_BLOCK_DONE;
 }
 
-
 /* Values for max_lazy_match, good_match and max_chain_length, depending on
  * the desired pack level (0..9). The values given below have been tuned to
  * exclude worst case performance for pathological files. Better values may be