Update zlib to 1.2.5.

third_party/zlib/deflate.c

 /* deflate.c -- compress data using the deflation algorithm
- * Copyright (C) 1995-2005 Jean-loup Gailly.
+ * Copyright (C) 1995-2010 Jean-loup Gailly and Mark Adler
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
 /*
  *  ALGORITHM
  *
  *      The "deflation" process depends on being able to identify portions
  *      of the input text which are identical to earlier input (within a
  *      sliding window trailing behind the input currently being processed).
  *
@@ skipping 27 matching lines @@
  *      Available in http://www.ietf.org/rfc/rfc1951.txt
  *
  *      A description of the Rabin and Karp algorithm is given in the book
  *         "Algorithms" by R. Sedgewick, Addison-Wesley, p252.
  *
  *      Fiala,E.R., and Greene,D.H.
  *         Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595
  *
  */
 
-/* @(#) $Id: deflate.c,v 3.6 2005/08/04 19:14:14 tor%cs.brown.edu Exp $ */
+/* @(#) $Id$ */
 
 #include "deflate.h"
 
 const char deflate_copyright[] =
-   " deflate 1.2.3 Copyright 1995-2005 Jean-loup Gailly ";
+   " deflate 1.2.5 Copyright 1995-2010 Jean-loup Gailly and Mark Adler ";
 /*
   If you use the zlib library in a product, an acknowledgment is welcome
   in the documentation of your product. If for some reason you cannot
   include such an acknowledgment, I would appreciate that you keep this
   copyright string in the executable of your product.
  */
 
 /* ===========================================================================
  *  Function prototypes.
  */
 typedef enum {
     need_more,      /* block not completed, need more input or more output */
     block_done,     /* block flush performed */
     finish_started, /* finish started, need only more output at next deflate */
     finish_done     /* finish done, accept no more input or output */
 } block_state;
 
 typedef block_state (*compress_func) OF((deflate_state *s, int flush));
 /* Compression function. Returns the block state after the call. */
 
 local void fill_window    OF((deflate_state *s));
 local block_state deflate_stored OF((deflate_state *s, int flush));
 local block_state deflate_fast   OF((deflate_state *s, int flush));
 #ifndef FASTEST
 local block_state deflate_slow   OF((deflate_state *s, int flush));
 #endif
+local block_state deflate_rle    OF((deflate_state *s, int flush));
+local block_state deflate_huff   OF((deflate_state *s, int flush));
 local void lm_init        OF((deflate_state *s));
 local void putShortMSB    OF((deflate_state *s, uInt b));
 local void flush_pending  OF((z_streamp strm));
 local int read_buf        OF((z_streamp strm, Bytef *buf, unsigned size));
-#ifndef FASTEST
 #ifdef ASMV
       void match_init OF((void)); /* asm code initialization */
       uInt longest_match  OF((deflate_state *s, IPos cur_match));
 #else
 local uInt longest_match  OF((deflate_state *s, IPos cur_match));
 #endif
-#endif
-local uInt longest_match_fast OF((deflate_state *s, IPos cur_match));
 
 #ifdef DEBUG
 local  void check_match OF((deflate_state *s, IPos start, IPos match,
                             int length));
 #endif
 
 /* ===========================================================================
  * Local data
  */
 
 #define NIL 0
 /* Tail of hash chains */
 
 #ifndef TOO_FAR
 #  define TOO_FAR 4096
 #endif
 /* Matches of length 3 are discarded if their distance exceeds TOO_FAR */
 
-#define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1)
-/* Minimum amount of lookahead, except at the end of the input file.
- * See deflate.c for comments about the MIN_MATCH+1.
- */
-
 /* 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
  * found for specific files.
  */
 typedef struct config_s {
    ush good_length; /* reduce lazy search above this match length */
    ush max_lazy;    /* do not perform lazy search above this match length */
    ush nice_length; /* quit search above this match length */
    ush max_chain;
@@ skipping 153 matching lines @@
 
     s->hash_bits = memLevel + 7;
     s->hash_size = 1 << s->hash_bits;
     s->hash_mask = s->hash_size - 1;
     s->hash_shift =  ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH);
 
     s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte));
     s->prev   = (Posf *)  ZALLOC(strm, s->w_size, sizeof(Pos));
     s->head   = (Posf *)  ZALLOC(strm, s->hash_size, sizeof(Pos));
 
+    s->high_water = 0;      /* nothing written to s->window yet */
+
     s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */
 
     overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2);
     s->pending_buf = (uchf *) overlay;
     s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L);
 
     if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL ||
         s->pending_buf == Z_NULL) {
         s->status = FINISH_STATE;
         strm->msg = (char*)ERR_MSG(Z_MEM_ERROR);
@@ skipping 24 matching lines @@
     if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL ||
         strm->state->wrap == 2 ||
         (strm->state->wrap == 1 && strm->state->status != INIT_STATE))
         return Z_STREAM_ERROR;
 
     s = strm->state;
     if (s->wrap)
         strm->adler = adler32(strm->adler, dictionary, dictLength);
 
     if (length < MIN_MATCH) return Z_OK;
-    if (length > MAX_DIST(s)) {
-        length = MAX_DIST(s);
+    if (length > s->w_size) {
+        length = s->w_size;
         dictionary += dictLength - length; /* use the tail of the dictionary */
     }
     zmemcpy(s->window, dictionary, length);
     s->strstart = length;
     s->block_start = (long)length;
 
     /* Insert all strings in the hash table (except for the last two bytes).
      * s->lookahead stays null, so s->ins_h will be recomputed at the next
      * call of fill_window.
      */
@@ skipping 81 matching lines @@
 #ifdef FASTEST
     if (level != 0) level = 1;
 #else
     if (level == Z_DEFAULT_COMPRESSION) level = 6;
 #endif
     if (level < 0 || level > 9 || strategy < 0 || strategy > Z_FIXED) {
         return Z_STREAM_ERROR;
     }
     func = configuration_table[s->level].func;
 
-    if (func != configuration_table[level].func && strm->total_in != 0) {
+    if ((strategy != s->strategy || func != configuration_table[level].func) &&
+        strm->total_in != 0) {
         /* Flush the last buffer: */
-        err = deflate(strm, Z_PARTIAL_FLUSH);
+        err = deflate(strm, Z_BLOCK);
     }
     if (s->level != level) {
         s->level = level;
         s->max_lazy_match   = configuration_table[level].max_lazy;
         s->good_match       = configuration_table[level].good_length;
         s->nice_match       = configuration_table[level].nice_length;
         s->max_chain_length = configuration_table[level].max_chain;
     }
     s->strategy = strategy;
     return err;
@@ skipping 23 matching lines @@
  * a close to exact, as well as small, upper bound on the compressed size.
  * They are coded as constants here for a reason--if the #define's are
  * changed, then this function needs to be changed as well.  The return
  * value for 15 and 8 only works for those exact settings.
  *
  * For any setting other than those defaults for windowBits and memLevel,
  * the value returned is a conservative worst case for the maximum expansion
  * resulting from using fixed blocks instead of stored blocks, which deflate
  * can emit on compressed data for some combinations of the parameters.
  *
- * This function could be more sophisticated to provide closer upper bounds
- * for every combination of windowBits and memLevel, as well as wrap.
- * But even the conservative upper bound of about 14% expansion does not
- * seem onerous for output buffer allocation.
+ * This function could be more sophisticated to provide closer upper bounds for
+ * every combination of windowBits and memLevel.  But even the conservative
+ * upper bound of about 14% expansion does not seem onerous for output buffer
+ * allocation.
  */
 uLong ZEXPORT deflateBound(strm, sourceLen)
     z_streamp strm;
     uLong sourceLen;
 {
     deflate_state *s;
-    uLong destLen;
+    uLong complen, wraplen;
+    Bytef *str;
 
-    /* conservative upper bound */
-    destLen = sourceLen +
-              ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 11;
+    /* conservative upper bound for compressed data */
+    complen = sourceLen +
+              ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 5;
 
-    /* if can't get parameters, return conservative bound */
+    /* if can't get parameters, return conservative bound plus zlib wrapper */
     if (strm == Z_NULL || strm->state == Z_NULL)
-        return destLen;
+        return complen + 6;
+
+    /* compute wrapper length */
+    s = strm->state;
+    switch (s->wrap) {
+    case 0:                                 /* raw deflate */
+        wraplen = 0;
+        break;
+    case 1:                                 /* zlib wrapper */
+        wraplen = 6 + (s->strstart ? 4 : 0);
+        break;
+    case 2:                                 /* gzip wrapper */
+        wraplen = 18;
+        if (s->gzhead != Z_NULL) {          /* user-supplied gzip header */
+            if (s->gzhead->extra != Z_NULL)
+                wraplen += 2 + s->gzhead->extra_len;
+            str = s->gzhead->name;
+            if (str != Z_NULL)
+                do {
+                    wraplen++;
+                } while (*str++);
+            str = s->gzhead->comment;
+            if (str != Z_NULL)
+                do {
+                    wraplen++;
+                } while (*str++);
+            if (s->gzhead->hcrc)
+                wraplen += 2;
+        }
+        break;
+    default:                                /* for compiler happiness */
+        wraplen = 6;
+    }
 
     /* if not default parameters, return conservative bound */
-    s = strm->state;
     if (s->w_bits != 15 || s->hash_bits != 8 + 7)
-        return destLen;
+        return complen + wraplen;
 
     /* default settings: return tight bound for that case */
-    return compressBound(sourceLen);
+    return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) +
+           (sourceLen >> 25) + 13 - 6 + wraplen;
 }
 
 /* =========================================================================
  * Put a short in the pending buffer. The 16-bit value is put in MSB order.
  * IN assertion: the stream state is correct and there is enough room in
  * pending_buf.
  */
 local void putShortMSB (s, b)
     deflate_state *s;
     uInt b;
@@ skipping 29 matching lines @@
 
 /* ========================================================================= */
 int ZEXPORT deflate (strm, flush)
     z_streamp strm;
     int flush;
 {
     int old_flush; /* value of flush param for previous deflate call */
     deflate_state *s;
 
     if (strm == Z_NULL || strm->state == Z_NULL ||
-        flush > Z_FINISH || flush < 0) {
+        flush > Z_BLOCK || flush < 0) {
         return Z_STREAM_ERROR;
     }
     s = strm->state;
 
     if (strm->next_out == Z_NULL ||
         (strm->next_in == Z_NULL && strm->avail_in != 0) ||
         (s->status == FINISH_STATE && flush != Z_FINISH)) {
         ERR_RETURN(strm, Z_STREAM_ERROR);
     }
     if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR);
 
     s->strm = strm; /* just in case */
     old_flush = s->last_flush;
     s->last_flush = flush;
 
     /* Write the header */
     if (s->status == INIT_STATE) {
 #ifdef GZIP
         if (s->wrap == 2) {
             strm->adler = crc32(0L, Z_NULL, 0);
             put_byte(s, 31);
             put_byte(s, 139);
             put_byte(s, 8);
-            if (s->gzhead == NULL) {
+            if (s->gzhead == Z_NULL) {
                 put_byte(s, 0);
                 put_byte(s, 0);
                 put_byte(s, 0);
                 put_byte(s, 0);
                 put_byte(s, 0);
                 put_byte(s, s->level == 9 ? 2 :
                             (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
                              4 : 0));
                 put_byte(s, OS_CODE);
                 s->status = BUSY_STATE;
             }
             else {
                 put_byte(s, (s->gzhead->text ? 1 : 0) +
                             (s->gzhead->hcrc ? 2 : 0) +
                             (s->gzhead->extra == Z_NULL ? 0 : 4) +
                             (s->gzhead->name == Z_NULL ? 0 : 8) +
                             (s->gzhead->comment == Z_NULL ? 0 : 16)
                         );
                 put_byte(s, (Byte)(s->gzhead->time & 0xff));
                 put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff));
                 put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff));
                 put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff));
                 put_byte(s, s->level == 9 ? 2 :
                             (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
                              4 : 0));
                 put_byte(s, s->gzhead->os & 0xff);
-                if (s->gzhead->extra != NULL) {
+                if (s->gzhead->extra != Z_NULL) {
                     put_byte(s, s->gzhead->extra_len & 0xff);
                     put_byte(s, (s->gzhead->extra_len >> 8) & 0xff);
                 }
                 if (s->gzhead->hcrc)
                     strm->adler = crc32(strm->adler, s->pending_buf,
                                         s->pending);
                 s->gzindex = 0;
                 s->status = EXTRA_STATE;
             }
         }
@@ skipping 21 matching lines @@
             /* Save the adler32 of the preset dictionary: */
             if (s->strstart != 0) {
                 putShortMSB(s, (uInt)(strm->adler >> 16));
                 putShortMSB(s, (uInt)(strm->adler & 0xffff));
             }
             strm->adler = adler32(0L, Z_NULL, 0);
         }
     }
 #ifdef GZIP
     if (s->status == EXTRA_STATE) {
-        if (s->gzhead->extra != NULL) {
+        if (s->gzhead->extra != Z_NULL) {
             uInt beg = s->pending;  /* start of bytes to update crc */
 
             while (s->gzindex < (s->gzhead->extra_len & 0xffff)) {
                 if (s->pending == s->pending_buf_size) {
                     if (s->gzhead->hcrc && s->pending > beg)
                         strm->adler = crc32(strm->adler, s->pending_buf + beg,
                                             s->pending - beg);
                     flush_pending(strm);
                     beg = s->pending;
                     if (s->pending == s->pending_buf_size)
                         break;
                 }
                 put_byte(s, s->gzhead->extra[s->gzindex]);
                 s->gzindex++;
             }
             if (s->gzhead->hcrc && s->pending > beg)
                 strm->adler = crc32(strm->adler, s->pending_buf + beg,
                                     s->pending - beg);
             if (s->gzindex == s->gzhead->extra_len) {
                 s->gzindex = 0;
                 s->status = NAME_STATE;
             }
         }
         else
             s->status = NAME_STATE;
     }
     if (s->status == NAME_STATE) {
-        if (s->gzhead->name != NULL) {
+        if (s->gzhead->name != Z_NULL) {
             uInt beg = s->pending;  /* start of bytes to update crc */
             int val;
 
             do {
                 if (s->pending == s->pending_buf_size) {
                     if (s->gzhead->hcrc && s->pending > beg)
                         strm->adler = crc32(strm->adler, s->pending_buf + beg,
                                             s->pending - beg);
                     flush_pending(strm);
                     beg = s->pending;
@@ skipping 10 matching lines @@
                                     s->pending - beg);
             if (val == 0) {
                 s->gzindex = 0;
                 s->status = COMMENT_STATE;
             }
         }
         else
             s->status = COMMENT_STATE;
     }
     if (s->status == COMMENT_STATE) {
-        if (s->gzhead->comment != NULL) {
+        if (s->gzhead->comment != Z_NULL) {
             uInt beg = s->pending;  /* start of bytes to update crc */
             int val;
 
             do {
                 if (s->pending == s->pending_buf_size) {
                     if (s->gzhead->hcrc && s->pending > beg)
                         strm->adler = crc32(strm->adler, s->pending_buf + beg,
                                             s->pending - beg);
                     flush_pending(strm);
                     beg = s->pending;
@@ skipping 57 matching lines @@
     if (s->status == FINISH_STATE && strm->avail_in != 0) {
         ERR_RETURN(strm, Z_BUF_ERROR);
     }
 
     /* Start a new block or continue the current one.
      */
     if (strm->avail_in != 0 || s->lookahead != 0 ||
         (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) {
         block_state bstate;
 
-        bstate = (*(configuration_table[s->level].func))(s, flush);
+        bstate = s->strategy == Z_HUFFMAN_ONLY ? deflate_huff(s, flush) :
+                    (s->strategy == Z_RLE ? deflate_rle(s, flush) :
+                        (*(configuration_table[s->level].func))(s, flush));
 
         if (bstate == finish_started || bstate == finish_done) {
             s->status = FINISH_STATE;
         }
         if (bstate == need_more || bstate == finish_started) {
             if (strm->avail_out == 0) {
                 s->last_flush = -1; /* avoid BUF_ERROR next call, see above */
             }
             return Z_OK;
             /* If flush != Z_NO_FLUSH && avail_out == 0, the next call
              * of deflate should use the same flush parameter to make sure
              * that the flush is complete. So we don't have to output an
              * empty block here, this will be done at next call. This also
              * ensures that for a very small output buffer, we emit at most
              * one empty block.
              */
         }
         if (bstate == block_done) {
             if (flush == Z_PARTIAL_FLUSH) {
                 _tr_align(s);
-            } else { /* FULL_FLUSH or SYNC_FLUSH */
+            } else if (flush != Z_BLOCK) { /* FULL_FLUSH or SYNC_FLUSH */
                 _tr_stored_block(s, (char*)0, 0L, 0);
                 /* For a full flush, this empty block will be recognized
                  * as a special marker by inflate_sync().
                  */
                 if (flush == Z_FULL_FLUSH) {
                     CLEAR_HASH(s);             /* forget history */
+                    if (s->lookahead == 0) {
+                        s->strstart = 0;
+                        s->block_start = 0L;
+                    }
                 }
             }
             flush_pending(strm);
             if (strm->avail_out == 0) {
               s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */
               return Z_OK;
             }
         }
     }
     Assert(strm->avail_out > 0, "bug2");
@@ skipping 332 matching lines @@
             scan_end   = scan[best_len];
 #endif
         }
     } while ((cur_match = prev[cur_match & wmask]) > limit
              && --chain_length != 0);
 
     if ((uInt)best_len <= s->lookahead) return (uInt)best_len;
     return s->lookahead;
 }
 #endif /* ASMV */
-#endif /* FASTEST */
+
+#else /* FASTEST */
 
 /* ---------------------------------------------------------------------------
- * Optimized version for level == 1 or strategy == Z_RLE only
+ * Optimized version for FASTEST only
  */
-local uInt longest_match_fast(s, cur_match)
+local uInt longest_match(s, cur_match)
     deflate_state *s;
     IPos cur_match;                             /* current match */
 {
     register Bytef *scan = s->window + s->strstart; /* current string */
     register Bytef *match;                       /* matched string */
     register int len;                           /* length of current match */
     register Bytef *strend = s->window + s->strstart + MAX_MATCH;
 
     /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
      * It is easy to get rid of this optimization if necessary.
@@ skipping 32 matching lines @@
     Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
 
     len = MAX_MATCH - (int)(strend - scan);
 
     if (len < MIN_MATCH) return MIN_MATCH - 1;
 
     s->match_start = cur_match;
     return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead;
 }
 
+#endif /* FASTEST */
+
 #ifdef DEBUG
 /* ===========================================================================
  * Check that the match at match_start is indeed a match.
  */
 local void check_match(s, start, match, length)
     deflate_state *s;
     IPos start, match;
     int length;
 {
     /* check that the match is indeed a match */
@@ skipping 58 matching lines @@
             s->match_start -= wsize;
             s->strstart    -= wsize; /* we now have strstart >= MAX_DIST */
             s->block_start -= (long) wsize;
 
             /* Slide the hash table (could be avoided with 32 bit values
                at the expense of memory usage). We slide even when level == 0
                to keep the hash table consistent if we switch back to level > 0
                later. (Using level 0 permanently is not an optimal usage of
                zlib, so we don't care about this pathological case.)
              */
-            /* %%% avoid this when Z_RLE */
             n = s->hash_size;
             p = &s->head[n];
             do {
                 m = *--p;
                 *p = (Pos)(m >= wsize ? m-wsize : NIL);
             } while (--n);
 
             n = wsize;
 #ifndef FASTEST
             p = &s->prev[n];
@@ skipping 31 matching lines @@
             UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);
 #if MIN_MATCH != 3
             Call UPDATE_HASH() MIN_MATCH-3 more times
 #endif
         }
         /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage,
          * but this is not important since only literal bytes will be emitted.
          */
 
     } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0);
+
+    /* If the WIN_INIT bytes after the end of the current data have never been
+     * written, then zero those bytes in order to avoid memory check reports of
+     * the use of uninitialized (or uninitialised as Julian writes) bytes by
+     * the longest match routines.  Update the high water mark for the next
+     * time through here.  WIN_INIT is set to MAX_MATCH since the longest match
+     * routines allow scanning to strstart + MAX_MATCH, ignoring lookahead.
+     */
+    if (s->high_water < s->window_size) {
+        ulg curr = s->strstart + (ulg)(s->lookahead);
+        ulg init;
+
+        if (s->high_water < curr) {
+            /* Previous high water mark below current data -- zero WIN_INIT
+             * bytes or up to end of window, whichever is less.
+             */
+            init = s->window_size - curr;
+            if (init > WIN_INIT)
+                init = WIN_INIT;
+            zmemzero(s->window + curr, (unsigned)init);
+            s->high_water = curr + init;
+        }
+        else if (s->high_water < (ulg)curr + WIN_INIT) {
+            /* High water mark at or above current data, but below current data
+             * plus WIN_INIT -- zero out to current data plus WIN_INIT, or up
+             * to end of window, whichever is less.
+             */
+            init = (ulg)curr + WIN_INIT - s->high_water;
+            if (init > s->window_size - s->high_water)
+                init = s->window_size - s->high_water;
+            zmemzero(s->window + s->high_water, (unsigned)init);
+            s->high_water += init;
+        }
+    }
 }
 
 /* ===========================================================================
  * Flush the current block, with given end-of-file flag.
  * IN assertion: strstart is set to the end of the current match.
  */
-#define FLUSH_BLOCK_ONLY(s, eof) { \
+#define FLUSH_BLOCK_ONLY(s, last) { \
    _tr_flush_block(s, (s->block_start >= 0L ? \
                    (charf *)&s->window[(unsigned)s->block_start] : \
                    (charf *)Z_NULL), \
                 (ulg)((long)s->strstart - s->block_start), \
-                (eof)); \
+                (last)); \
    s->block_start = s->strstart; \
    flush_pending(s->strm); \
    Tracev((stderr,"[FLUSH]")); \
 }
 
 /* Same but force premature exit if necessary. */
-#define FLUSH_BLOCK(s, eof) { \
-   FLUSH_BLOCK_ONLY(s, eof); \
-   if (s->strm->avail_out == 0) return (eof) ? finish_started : need_more; \
+#define FLUSH_BLOCK(s, last) { \
+   FLUSH_BLOCK_ONLY(s, last); \
+   if (s->strm->avail_out == 0) return (last) ? finish_started : need_more; \
 }
 
 /* ===========================================================================
  * Copy without compression as much as possible from the input stream, return
  * the current block state.
  * This function does not insert new strings in the dictionary since
  * uncompressible data is probably not useful. This function is used
  * only for the level=0 compression option.
  * NOTE: this function should be optimized to avoid extra copying from
  * window to pending_buf.
@@ skipping 53 matching lines @@
  * Compress as much as possible from the input stream, return the current
  * block state.
  * This function does not perform lazy evaluation of matches and inserts
  * new strings in the dictionary only for unmatched strings or for short
  * matches. It is used only for the fast compression options.
  */
 local block_state deflate_fast(s, flush)
     deflate_state *s;
     int flush;
 {
-    IPos hash_head = NIL; /* head of the hash chain */
+    IPos hash_head;       /* head of the hash chain */
     int bflush;           /* set if current block must be flushed */
 
     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 == Z_NO_FLUSH) {
                 return 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);
         }
 
         /* Find the longest match, discarding those <= prev_length.
          * At this point we have always match_length < MIN_MATCH
          */
         if (hash_head != NIL && s->strstart - hash_head <= 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).
              */
-#ifdef FASTEST
-            if ((s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) ||
-                (s->strategy == Z_RLE && s->strstart - hash_head == 1)) {
-                s->match_length = longest_match_fast (s, hash_head);
-            }
-#else
-            if (s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) {
-                s->match_length = longest_match (s, hash_head);
-            } else if (s->strategy == Z_RLE && s->strstart - hash_head == 1) {
-                s->match_length = longest_match_fast (s, hash_head);
-            }
-#endif
-            /* longest_match() or longest_match_fast() sets match_start */
+            s->match_length = longest_match (s, hash_head);
+            /* longest_match() sets match_start */
         }
         if (s->match_length >= MIN_MATCH) {
             check_match(s, s->strstart, s->match_start, s->match_length);
 
             _tr_tally_dist(s, s->strstart - s->match_start,
                            s->match_length - MIN_MATCH, bflush);
 
             s->lookahead -= s->match_length;
 
             /* Insert new strings in the hash table only if the match length
@@ skipping 41 matching lines @@
 #ifndef FASTEST
 /* ===========================================================================
  * Same as above, but achieves better compression. We use a lazy
  * evaluation for matches: a match is finally adopted only if there is
  * no better match at the next window position.
  */
 local block_state deflate_slow(s, flush)
     deflate_state *s;
     int flush;
 {
-    IPos hash_head = NIL;    /* head of hash chain */
+    IPos hash_head;          /* head of hash chain */
     int bflush;              /* set if current block must be flushed */
 
     /* 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 == Z_NO_FLUSH) {
                 return 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);
         }
 
         /* 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 <= 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).
              */
-            if (s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) {
-                s->match_length = longest_match (s, hash_head);
-            } else if (s->strategy == Z_RLE && s->strstart - hash_head == 1) {
-                s->match_length = longest_match_fast (s, hash_head);
-            }
-            /* longest_match() or longest_match_fast() sets match_start */
+            s->match_length = longest_match (s, hash_head);
+            /* longest_match() sets match_start */
 
             if (s->match_length <= 5 && (s->strategy == Z_FILTERED
 #if TOO_FAR <= 32767
                 || (s->match_length == MIN_MATCH &&
                     s->strstart - s->match_start > TOO_FAR)
 #endif
                 )) {
 
                 /* If prev_match is also MIN_MATCH, match_start is garbage
                  * but we will ignore the current match anyway.
@@ skipping 57 matching lines @@
     if (s->match_available) {
         Tracevv((stderr,"%c", s->window[s->strstart-1]));
         _tr_tally_lit(s, s->window[s->strstart-1], bflush);
         s->match_available = 0;
     }
     FLUSH_BLOCK(s, flush == Z_FINISH);
     return flush == Z_FINISH ? finish_done : block_done;
 }
 #endif /* FASTEST */
 
-#if 0
 /* ===========================================================================
  * 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.)
  */
 local block_state deflate_rle(s, flush)
     deflate_state *s;
     int flush;
 {
-    int bflush;         /* set if current block must be flushed */
-    uInt run;           /* length of run */
-    uInt max;           /* maximum length of run */
-    uInt prev;          /* byte at distance one to match */
-    Bytef *scan;        /* scan for end of run */
+    int bflush;             /* set if current block must be flushed */
+    uInt prev;              /* byte at distance one to match */
+    Bytef *scan, *strend;   /* scan goes up to strend for length of run */
 
     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 encodable run.
          */
         if (s->lookahead < MAX_MATCH) {
             fill_window(s);
             if (s->lookahead < MAX_MATCH && flush == Z_NO_FLUSH) {
                 return need_more;
             }
             if (s->lookahead == 0) break; /* flush the current block */
         }
 
         /* See how many times the previous byte repeats */
-        run = 0;
-        if (s->strstart > 0) {      /* if there is a previous byte, that is */
-            max = s->lookahead < MAX_MATCH ? s->lookahead : MAX_MATCH;
+        s->match_length = 0;
+        if (s->lookahead >= MIN_MATCH && s->strstart > 0) {
             scan = s->window + s->strstart - 1;
-            prev = *scan++;
-            do {
-                if (*scan++ != prev)
-                    break;
-            } while (++run < max);
+            prev = *scan;
+            if (prev == *++scan && prev == *++scan && prev == *++scan) {
+                strend = s->window + s->strstart + MAX_MATCH;
+                do {
+                } while (prev == *++scan && prev == *++scan &&
+                         prev == *++scan && prev == *++scan &&
+                         prev == *++scan && prev == *++scan &&
+                         prev == *++scan && prev == *++scan &&
+                         scan < strend);
+                s->match_length = MAX_MATCH - (int)(strend - scan);
+                if (s->match_length > s->lookahead)
+                    s->match_length = s->lookahead;
+            }
         }
 
         /* Emit match if have run of MIN_MATCH or longer, else emit literal */
-        if (run >= MIN_MATCH) {
-            check_match(s, s->strstart, s->strstart - 1, run);
-            _tr_tally_dist(s, 1, run - MIN_MATCH, bflush);
-            s->lookahead -= run;
-            s->strstart += run;
+        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);
+
+            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);
             s->lookahead--;
             s->strstart++;
         }
         if (bflush) FLUSH_BLOCK(s, 0);
     }
     FLUSH_BLOCK(s, flush == Z_FINISH);
     return flush == Z_FINISH ? finish_done : block_done;
 }
-#endif
+
+/* ===========================================================================
+ * 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.)
+ */
+local block_state deflate_huff(s, flush)
+    deflate_state *s;
+    int flush;
+{
+    int 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 == Z_NO_FLUSH)
+                    return 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);
+        s->lookahead--;
+        s->strstart++;
+        if (bflush) FLUSH_BLOCK(s, 0);
+    }
+    FLUSH_BLOCK(s, flush == Z_FINISH);
+    return flush == Z_FINISH ? finish_done : block_done;
+}