1 /* deflate.c -- compress data using the deflation algorithm

     2  * Copyright (C) 1995-2002 Jean-loup Gailly.

     3  * For conditions of distribution and use, see copyright notice in zlib.h 

     4  */

     5 

     6 /*

     7  *  ALGORITHM

     8  *

     9  *      The "deflation" process depends on being able to identify portions

    10  *      of the input text which are identical to earlier input (within a

    11  *      sliding window trailing behind the input currently being processed).

    12  *

    13  *      The most straightforward technique turns out to be the fastest for

    14  *      most input files: try all possible matches and select the longest.

    15  *      The key feature of this algorithm is that insertions into the string

    16  *      dictionary are very simple and thus fast, and deletions are avoided

    17  *      completely. Insertions are performed at each input character, whereas

    18  *      string matches are performed only when the previous match ends. So it

    19  *      is preferable to spend more time in matches to allow very fast string

    20  *      insertions and avoid deletions. The matching algorithm for small

    21  *      strings is inspired from that of Rabin & Karp. A brute force approach

    22  *      is used to find longer strings when a small match has been found.

    23  *      A similar algorithm is used in comic (by Jan-Mark Wams) and freeze

    24  *      (by Leonid Broukhis).

    25  *         A previous version of this file used a more sophisticated algorithm

    26  *      (by Fiala and Greene) which is guaranteed to run in linear amortized

    27  *      time, but has a larger average cost, uses more memory and is patented.

    28  *      However the F&G algorithm may be faster for some highly redundant

    29  *      files if the parameter max_chain_length (described below) is too large.

    30  *

    31  *  ACKNOWLEDGEMENTS

    32  *

    33  *      The idea of lazy evaluation of matches is due to Jan-Mark Wams, and

    34  *      I found it in 'freeze' written by Leonid Broukhis.

    35  *      Thanks to many people for bug reports and testing.

    36  *

    37  *  REFERENCES

    38  *

    39  *      Deutsch, L.P.,"DEFLATE Compressed Data Format Specification".

    40  *      Available in ftp://ds.internic.net/rfc/rfc1951.txt

    41  *

    42  *      A description of the Rabin and Karp algorithm is given in the book

    43  *         "Algorithms" by R. Sedgewick, Addison-Wesley, p252.

    44  *

    45  *      Fiala,E.R., and Greene,D.H.

    46  *         Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595

    47  *

    48  */

    49 

    50 /* @(#) $Id$ */

    51 

    52 #include <e32def.h>

    53 

    54 #include "deflate.h"

    55 

    56 const char deflate_copyright[] =

    57    " deflate 1.1.4 Copyright 1995-2002 Jean-loup Gailly ";

    58 /*

    59   If you use the zlib library in a product, an acknowledgment is welcome

    60   in the documentation of your product. If for some reason you cannot

    61   include such an acknowledgment, I would appreciate that you keep this

    62   copyright string in the executable of your product.

    63  */

    64 

    65 /* ===========================================================================

    66  *  Function prototypes.

    67  */

    68 typedef enum {

    69     need_more,      /* block not completed, need more input or more output */

    70     block_done,     /* block flush performed */

    71     finish_started, /* finish started, need only more output at next deflate */

    72     finish_done     /* finish done, accept no more input or output */

    73 } block_state;

    74 

    75 typedef block_state (*compress_func) OF((deflate_state *s, int flush));

    76 /* Compression function. Returns the block state after the call. */

    77 

    78 local void fill_window    OF((deflate_state *s));

    79 local block_state deflate_stored OF((deflate_state *s, int flush));

    80 local block_state deflate_fast   OF((deflate_state *s, int flush));

    81 local block_state deflate_slow   OF((deflate_state *s, int flush));

    82 local void lm_init        OF((deflate_state *s));

    83 local void putShortMSB    OF((deflate_state *s, uInt b));

    84 local void flush_pending  OF((z_streamp strm));

    85 local int read_buf        OF((z_streamp strm, Bytef *buf, unsigned size));

    86 #ifdef ASMV

    87       void match_init OF((void)); /* asm code initialization */

    88       uInt longest_match  OF((deflate_state *s, IPos cur_match));

    89 #else

    90 local uInt longest_match  OF((deflate_state *s, IPos cur_match));

    91 #endif

    92 

    93 #ifdef DEBUG

    94 local  void check_match OF((deflate_state *s, IPos start, IPos match,

    95                             int length));

    96 #endif

    97 

    98 /* ===========================================================================

    99  * Local data

   100  */

   101 

   102 #define NIL 0

   103 /* Tail of hash chains */

   104 

   105 #ifndef TOO_FAR

   106 #  define TOO_FAR 4096

   107 #endif

   108 /* Matches of length 3 are discarded if their distance exceeds TOO_FAR */

   109 

   110 #define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1)

   111 /* Minimum amount of lookahead, except at the end of the input file.

   112  * See deflate.c for comments about the MIN_MATCH+1.

   113  */

   114 

   115 /* Values for max_lazy_match, good_match and max_chain_length, depending on

   116  * the desired pack level (0..9). The values given below have been tuned to

   117  * exclude worst case performance for pathological files. Better values may be

   118  * found for specific files.

   119  */

   120 typedef struct config_s {

   121    ush good_length; /* reduce lazy search above this match length */

   122    ush max_lazy;    /* do not perform lazy search above this match length */

   123    ush nice_length; /* quit search above this match length */

   124    ush max_chain;

   125    compress_func func;

   126 } config;

   127 

   128 local const config configuration_table[10] = {

   129 /*      good lazy nice chain */

   130 /* 0 */ {0,    0,  0,    0, deflate_stored},  /* store only */

   131 /* 1 */ {4,    4,  8,    4, deflate_fast}, /* maximum speed, no lazy matches */

   132 /* 2 */ {4,    5, 16,    8, deflate_fast},

   133 /* 3 */ {4,    6, 32,   32, deflate_fast},

   134 

   135 /* 4 */ {4,    4, 16,   16, deflate_slow},  /* lazy matches */

   136 /* 5 */ {8,   16, 32,   32, deflate_slow},

   137 /* 6 */ {8,   16, 128, 128, deflate_slow},

   138 /* 7 */ {8,   32, 128, 256, deflate_slow},

   139 /* 8 */ {32, 128, 258, 1024, deflate_slow},

   140 /* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* maximum compression */

   141 

   142 /* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4

   143  * For deflate_fast() (levels <= 3) good is ignored and lazy has a different

   144  * meaning.

   145  */

   146 

   147 #define EQUAL 0

   148 /* result of memcmp for equal strings */

   149 

   150 struct static_tree_desc_s {int dummy;}; /* for buggy compilers */

   151 

   152 /* ===========================================================================

   153  * Update a hash value with the given input byte

   154  * IN  assertion: all calls to to UPDATE_HASH are made with consecutive

   155  *    input characters, so that a running hash key can be computed from the

   156  *    previous key instead of complete recalculation each time.

   157  */

   158 #define UPDATE_HASH(s,h,c) (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask)

   159 

   160 

   161 /* ===========================================================================

   162  * Insert string str in the dictionary and set match_head to the previous head

   163  * of the hash chain (the most recent string with same hash key). Return

   164  * the previous length of the hash chain.

   165  * If this file is compiled with -DFASTEST, the compression level is forced

   166  * to 1, and no hash chains are maintained.

   167  * IN  assertion: all calls to to INSERT_STRING are made with consecutive

   168  *    input characters and the first MIN_MATCH bytes of str are valid

   169  *    (except for the last MIN_MATCH-1 bytes of the input file).

   170  */

   171 #ifdef FASTEST

   172 #define INSERT_STRING(s, str, match_head) \

   173    (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \

   174     match_head = s->head[s->ins_h], \

   175     s->head[s->ins_h] = STATIC_CAST(Pos,str))

   176 #else

   177 #define INSERT_STRING(s, str, match_head) \

   178    (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \

   179     s->prev[(str) & s->w_mask] = STATIC_CAST(Posf,match_head = s->head[s->ins_h]), \

   180     s->head[s->ins_h] = STATIC_CAST(Pos,str))

   181 #endif

   182 

   183 /* ===========================================================================

   184  * Initialize the hash table (avoiding 64K overflow for 16 bit systems).

   185  * prev[] will be initialized on the fly.

   186  */

   187 #define CLEAR_HASH(s) \

   188     s->head[s->hash_size-1] = NIL; \

   189     zmemzero((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head));

   190 

   191 /* ========================================================================= */

   192 EXPORT_C int ZEXPORT deflateInit_(

   193     z_streamp strm,

   194     int level,

   195     const char *version,

   196     int stream_size)

   197 {

   198     return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL,

   199 			 Z_DEFAULT_STRATEGY, version, stream_size);

   200     /* To do: ignore strm->next_in if we use it as window */

   201 }

   202 

   203 /* ========================================================================= */

   204 EXPORT_C int ZEXPORT deflateInit2_(

   205     z_streamp strm,

   206     int  level,

   207     int  method,

   208     int  windowBits,

   209     int  memLevel,

   210     int  strategy,

   211     const char *version,

   212     int stream_size)

   213 {

   214     deflate_state *s;

   215     int noheader = 0;

   216     static const char* const my_version = ZLIB_VERSION;

   217 

   218     ushf *overlay;

   219     /* We overlay pending_buf and d_buf+l_buf. This works since the average

   220      * output size for (length,distance) codes is <= 24 bits.

   221      */

   222 

   223     if (version == Z_NULL || version[0] != my_version[0] ||

   224         stream_size != sizeof(z_stream)) {

   225 	return Z_VERSION_ERROR;

   226     }

   227     if (strm == Z_NULL) return Z_STREAM_ERROR;

   228 

   229     strm->msg = Z_NULL;

   230     if (strm->zalloc == Z_NULL) {

   231 	strm->zalloc = zcalloc;

   232 	strm->opaque = (voidpf)0;

   233     }

   234     if (strm->zfree == Z_NULL) strm->zfree = zcfree;

   235 

   236     if (level == Z_DEFAULT_COMPRESSION) level = 6;

   237 #ifdef FASTEST

   238     level = 1;

   239 #endif

   240 

   241     if (windowBits < 0) { /* undocumented feature: suppress zlib header */

   242         noheader = 1;

   243         windowBits = -windowBits;

   244     }

   245     if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED ||

   246         windowBits < 9 || windowBits > 15 || level < 0 || level > 9 ||

   247 	strategy < 0 || strategy > Z_HUFFMAN_ONLY) {

   248         return Z_STREAM_ERROR;

   249     }

   250     s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state));

   251     if (s == Z_NULL) return Z_MEM_ERROR;

   252     strm->state = (struct internal_state FAR *)s;

   253     s->strm = strm;

   254 

   255     s->noheader = noheader;

   256     s->w_bits = windowBits;

   257     s->w_size = 1 << s->w_bits;

   258     s->w_mask = s->w_size - 1;

   259 

   260     s->hash_bits = memLevel + 7;

   261     s->hash_size = 1 << s->hash_bits;

   262     s->hash_mask = s->hash_size - 1;

   263     s->hash_shift =  ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH);

   264 

   265     s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte));

   266     s->prev   = (Posf *)  ZALLOC(strm, s->w_size, sizeof(Pos));

   267     s->head   = (Posf *)  ZALLOC(strm, s->hash_size, sizeof(Pos));

   268 

   269     s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */

   270 

   271     overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2);

   272     s->pending_buf = (uchf *) overlay;

   273     s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L);

   274 

   275     if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL ||

   276         s->pending_buf == Z_NULL) {

   277         strm->msg = (char*)ERR_MSG(Z_MEM_ERROR);

   278 

   279 		// The following line has been added by Markr.  Up to this point s->status has not been 

   280 		// initialised.  If this is the case when deflateEnd is called then it will fail to reclaim

   281 		// the memory allocated for s->window etc when alloc fails.  Setting the status to INIT_STATE

   282 		// allows deflateEnd to reclaim memory.

   283 

   284 		s->status = INIT_STATE; 

   285         deflateEnd (strm);

   286         return Z_MEM_ERROR;

   287     }

   288     s->d_buf = overlay + s->lit_bufsize/sizeof(ush);

   289     s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize;

   290 

   291     s->level = level;

   292     s->strategy = strategy;

   293     s->method = (Byte)method;

   294 

   295     return deflateReset(strm);

   296 }

   297 

   298 /* ========================================================================= */

   299 EXPORT_C int ZEXPORT deflateSetDictionary (

   300     z_streamp strm,

   301     const Bytef *dictionary,

   302     uInt  dictLength)

   303 {

   304 	// Line to stop compiler warning about unused mandatory global variable

   305 	char __z=deflate_copyright[0]; __z=__z;

   306 

   307 	deflate_state *s;

   308     uInt length = dictLength;

   309     uInt n;

   310     IPos hash_head = 0;

   311 

   312     if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL ||

   313         strm->state->status != INIT_STATE) return Z_STREAM_ERROR;

   314 

   315     s = strm->state;

   316     strm->adler = adler32(strm->adler, dictionary, dictLength);

   317 

   318     if (length < MIN_MATCH) return Z_OK;

   319     if (length > MAX_DIST(s)) {

   320 	length = MAX_DIST(s);

   321 #ifndef USE_DICT_HEAD

   322 	dictionary += dictLength - length; /* use the tail of the dictionary */

   323 #endif

   324     }

   325     zmemcpy(s->window, dictionary, length);

   326     s->strstart = length;

   327     s->block_start = (long)length;

   328 

   329     /* Insert all strings in the hash table (except for the last two bytes).

   330      * s->lookahead stays null, so s->ins_h will be recomputed at the next

   331      * call of fill_window.

   332      */

   333     s->ins_h = s->window[0];

   334     UPDATE_HASH(s, s->ins_h, s->window[1]);

   335     for (n = 0; n <= length - MIN_MATCH; n++) {

   336 	INSERT_STRING(s, n, hash_head);

   337     }

   338     if (hash_head) hash_head = 0;  /* to make compiler happy */

   339     return Z_OK;

   340 }

   341 

   342 /* ========================================================================= */

   343 EXPORT_C int ZEXPORT deflateReset (

   344     z_streamp strm)

   345 {

   346     deflate_state *s;

   347     

   348     if (strm == Z_NULL || strm->state == Z_NULL ||

   349         strm->zalloc == Z_NULL || strm->zfree == Z_NULL) return Z_STREAM_ERROR;

   350 

   351     strm->total_in = strm->total_out = 0;

   352     strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */

   353     strm->data_type = Z_UNKNOWN;

   354 

   355     s = (deflate_state *)strm->state;

   356     s->pending = 0;

   357     s->pending_out = s->pending_buf;

   358 

   359     if (s->noheader < 0) {

   360         s->noheader = 0; /* was set to -1 by deflate(..., Z_FINISH); */

   361     }

   362     s->status = s->noheader ? BUSY_STATE : INIT_STATE;

   363     strm->adler = 1;

   364     s->last_flush = Z_NO_FLUSH;

   365 

   366     _tr_init(s);

   367     lm_init(s);

   368 

   369     return Z_OK;

   370 }

   371 

   372 /* ========================================================================= */

   373 EXPORT_C int ZEXPORT deflateParams(

   374     z_streamp strm,

   375     int level,

   376     int strategy)

   377 {

   378     deflate_state *s;

   379     compress_func func;

   380     int err = Z_OK;

   381 

   382     if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;

   383     s = strm->state;

   384 

   385     if (level == Z_DEFAULT_COMPRESSION) {

   386 	level = 6;

   387     }

   388     if (level < 0 || level > 9 || strategy < 0 || strategy > Z_HUFFMAN_ONLY) {

   389 	return Z_STREAM_ERROR;

   390     }

   391     func = configuration_table[s->level].func;

   392 

   393     if (func != configuration_table[level].func && strm->total_in != 0) {

   394 	/* Flush the last buffer: */

   395 	err = deflate(strm, Z_PARTIAL_FLUSH);

   396     }

   397     if (s->level != level) {

   398 	s->level = level;

   399 	s->max_lazy_match   = configuration_table[level].max_lazy;

   400 	s->good_match       = configuration_table[level].good_length;

   401 	s->nice_match       = configuration_table[level].nice_length;

   402 	s->max_chain_length = configuration_table[level].max_chain;

   403     }

   404     s->strategy = strategy;

   405     return err;

   406 }

   407 

   408 /* =========================================================================

   409  * Put a short in the pending buffer. The 16-bit value is put in MSB order.

   410  * IN assertion: the stream state is correct and there is enough room in

   411  * pending_buf.

   412  */

   413 local void putShortMSB (

   414     deflate_state *s,

   415     uInt b)

   416 {

   417     put_byte(s, (Byte)(b >> 8));

   418     put_byte(s, (Byte)(b & 0xff));

   419 }   

   420 

   421 /* =========================================================================

   422  * Flush as much pending output as possible. All deflate() output goes

   423  * through this function so some applications may wish to modify it

   424  * to avoid allocating a large strm->next_out buffer and copying into it.

   425  * (See also read_buf()).

   426  */

   427 local void flush_pending(

   428     z_streamp strm)

   429 {

   430     unsigned len = strm->state->pending;

   431 

   432     if (len > strm->avail_out) len = strm->avail_out;

   433     if (len == 0) return;

   434 

   435     zmemcpy(strm->next_out, strm->state->pending_out, len);

   436     strm->next_out  += len;

   437     strm->state->pending_out  += len;

   438     strm->total_out += len;

   439     strm->avail_out  -= len;

   440     strm->state->pending -= len;

   441     if (strm->state->pending == 0) {

   442         strm->state->pending_out = strm->state->pending_buf;

   443     }

   444 }

   445 

   446 /* ========================================================================= */

   447 EXPORT_C int ZEXPORT deflate (

   448     z_streamp strm,

   449     int flush)

   450 {

   451     int old_flush; /* value of flush param for previous deflate call */

   452     deflate_state *s;

   453 

   454     if (strm == Z_NULL || strm->state == Z_NULL ||

   455 	flush > Z_FINISH || flush < 0) {

   456         return Z_STREAM_ERROR;

   457     }

   458     s = strm->state;

   459 

   460     if (strm->next_out == Z_NULL ||

   461         (strm->next_in == Z_NULL && strm->avail_in != 0) ||

   462 	(s->status == FINISH_STATE && flush != Z_FINISH)) {

   463         ERR_RETURN(strm, Z_STREAM_ERROR);

   464     }

   465     if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR);

   466 

   467     s->strm = strm; /* just in case */

   468     old_flush = s->last_flush;

   469     s->last_flush = flush;

   470 

   471     /* Write the zlib header */

   472     if (s->status == INIT_STATE) {

   473 

   474         uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8;

   475         uInt level_flags = (s->level-1) >> 1;

   476 

   477         if (level_flags > 3) level_flags = 3;

   478         header |= (level_flags << 6);

   479 	if (s->strstart != 0) header |= PRESET_DICT;

   480         header += 31 - (header % 31);

   481 

   482         s->status = BUSY_STATE;

   483         putShortMSB(s, header);

   484 

   485 	/* Save the adler32 of the preset dictionary: */

   486 	if (s->strstart != 0) {

   487 	    putShortMSB(s, (uInt)(strm->adler >> 16));

   488 	    putShortMSB(s, (uInt)(strm->adler & 0xffff));

   489 	}

   490 	strm->adler = 1L;

   491     }

   492 

   493     /* Flush as much pending output as possible */

   494     if (s->pending != 0) {

   495         flush_pending(strm);

   496         if (strm->avail_out == 0) {

   497 	    /* Since avail_out is 0, deflate will be called again with

   498 	     * more output space, but possibly with both pending and

   499 	     * avail_in equal to zero. There won't be anything to do,

   500 	     * but this is not an error situation so make sure we

   501 	     * return OK instead of BUF_ERROR at next call of deflate:

   502              */

   503 	    s->last_flush = -1;

   504 	    return Z_OK;

   505 	}

   506 

   507     /* Make sure there is something to do and avoid duplicate consecutive

   508      * flushes. For repeated and useless calls with Z_FINISH, we keep

   509      * returning Z_STREAM_END instead of Z_BUFF_ERROR.

   510      */

   511     } else if (strm->avail_in == 0 && flush <= old_flush &&

   512 	       flush != Z_FINISH) {

   513         ERR_RETURN(strm, Z_BUF_ERROR);

   514     }

   515 

   516     /* User must not provide more input after the first FINISH: */

   517     if (s->status == FINISH_STATE && strm->avail_in != 0) {

   518         ERR_RETURN(strm, Z_BUF_ERROR);

   519     }

   520 

   521     /* Start a new block or continue the current one.

   522      */

   523     if (strm->avail_in != 0 || s->lookahead != 0 ||

   524         (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) {

   525         block_state bstate;

   526 

   527 	bstate = (*(configuration_table[s->level].func))(s, flush);

   528 

   529         if (bstate == finish_started || bstate == finish_done) {

   530             s->status = FINISH_STATE;

   531         }

   532         if (bstate == need_more || bstate == finish_started) {

   533 	    if (strm->avail_out == 0) {

   534 	        s->last_flush = -1; /* avoid BUF_ERROR next call, see above */

   535 	    }

   536 	    return Z_OK;

   537 	    /* If flush != Z_NO_FLUSH && avail_out == 0, the next call

   538 	     * of deflate should use the same flush parameter to make sure

   539 	     * that the flush is complete. So we don't have to output an

   540 	     * empty block here, this will be done at next call. This also

   541 	     * ensures that for a very small output buffer, we emit at most

   542 	     * one empty block.

   543 	     */

   544 	}

   545         if (bstate == block_done) {

   546             if (flush == Z_PARTIAL_FLUSH) {

   547                 _tr_align(s);

   548             } else { /* FULL_FLUSH or SYNC_FLUSH */

   549                 _tr_stored_block(s, (char*)0, 0L, 0);

   550                 /* For a full flush, this empty block will be recognized

   551                  * as a special marker by inflate_sync().

   552                  */

   553                 if (flush == Z_FULL_FLUSH) {

   554                     CLEAR_HASH(s);             /* forget history */

   555                 }

   556             }

   557             flush_pending(strm);

   558 	    if (strm->avail_out == 0) {

   559 	      s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */

   560 	      return Z_OK;

   561 	    }

   562         }

   563     }

   564     Assert(strm->avail_out > 0, "bug2");

   565 

   566     if (flush != Z_FINISH) return Z_OK;

   567     if (s->noheader) return Z_STREAM_END;

   568 

   569     /* Write the zlib trailer (adler32) */

   570     putShortMSB(s, (uInt)(strm->adler >> 16));

   571     putShortMSB(s, (uInt)(strm->adler & 0xffff));

   572     flush_pending(strm);

   573     /* If avail_out is zero, the application will call deflate again

   574      * to flush the rest.

   575      */

   576     s->noheader = -1; /* write the trailer only once! */

   577     return s->pending != 0 ? Z_OK : Z_STREAM_END;

   578 }

   579 

   580 /* ========================================================================= */

   581 EXPORT_C int ZEXPORT deflateEnd (

   582     z_streamp strm)

   583 {

   584     int status;

   585 

   586     if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;

   587 

   588     status = strm->state->status;

   589     if (status != INIT_STATE && status != BUSY_STATE &&

   590 	status != FINISH_STATE) {

   591       return Z_STREAM_ERROR;

   592     }

   593 

   594     /* Deallocate in reverse order of allocations: */

   595     TRY_FREE(strm, strm->state->pending_buf);

   596     TRY_FREE(strm, strm->state->head);

   597     TRY_FREE(strm, strm->state->prev);

   598     TRY_FREE(strm, strm->state->window);

   599 

   600     ZFREE(strm, strm->state);

   601     strm->state = Z_NULL;

   602 

   603     return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK;

   604 }

   605 

   606 /* =========================================================================

   607  * Copy the source state to the destination state.

   608  * To simplify the source, this is not supported for 16-bit MSDOS (which

   609  * doesn't have enough memory anyway to duplicate compression states).

   610  */

   611 EXPORT_C int ZEXPORT deflateCopy (

   612     z_streamp dest,

   613     z_streamp source)

   614 {

   615 #ifdef MAXSEG_64K

   616     return Z_STREAM_ERROR;

   617 #else

   618     deflate_state *ds;

   619     deflate_state *ss;

   620     ushf *overlay;

   621 

   622 

   623     if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL) {

   624         return Z_STREAM_ERROR;

   625     }

   626 

   627     ss = source->state;

   628 

   629     *dest = *source;

   630 

   631     ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state));

   632     if (ds == Z_NULL) return Z_MEM_ERROR;

   633     dest->state = (struct internal_state FAR *) ds;

   634     *ds = *ss;

   635     ds->strm = dest;

   636 

   637     ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte));

   638     ds->prev   = (Posf *)  ZALLOC(dest, ds->w_size, sizeof(Pos));

   639     ds->head   = (Posf *)  ZALLOC(dest, ds->hash_size, sizeof(Pos));

   640     overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2);

   641     ds->pending_buf = (uchf *) overlay;

   642 

   643     if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL ||

   644         ds->pending_buf == Z_NULL) {

   645         deflateEnd (dest);

   646         return Z_MEM_ERROR;

   647     }

   648     /* following zmemcpy do not work for 16-bit MSDOS */

   649     zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte));

   650     zmemcpy(ds->prev, ss->prev, ds->w_size * sizeof(Pos));

   651     zmemcpy(ds->head, ss->head, ds->hash_size * sizeof(Pos));

   652     zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size);

   653 

   654     ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf);

   655     ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush);

   656     ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize;

   657 

   658     ds->l_desc.dyn_tree = ds->dyn_ltree;

   659     ds->d_desc.dyn_tree = ds->dyn_dtree;

   660     ds->bl_desc.dyn_tree = ds->bl_tree;

   661 

   662     return Z_OK;

   663 #endif

   664 }

   665 

   666 /* ===========================================================================

   667  * Read a new buffer from the current input stream, update the adler32

   668  * and total number of bytes read.  All deflate() input goes through

   669  * this function so some applications may wish to modify it to avoid

   670  * allocating a large strm->next_in buffer and copying from it.

   671  * (See also flush_pending()).

   672  */

   673 local int read_buf(

   674     z_streamp strm,

   675     Bytef *buf,

   676     unsigned size)

   677 {

   678     unsigned len = strm->avail_in;

   679 

   680     if (len > size) len = size;

   681     if (len == 0) return 0;

   682 

   683     strm->avail_in  -= len;

   684 

   685     if (!strm->state->noheader) {

   686         strm->adler = adler32(strm->adler, strm->next_in, len);

   687     }

   688     zmemcpy(buf, strm->next_in, len);

   689     strm->next_in  += len;

   690     strm->total_in += len;

   691 

   692     return (int)len;

   693 }

   694 

   695 /* ===========================================================================

   696  * Initialize the "longest match" routines for a new zlib stream

   697  */

   698 local void lm_init (

   699     deflate_state *s)

   700 {

   701     s->window_size = (ulg)2L*s->w_size;

   702 

   703     CLEAR_HASH(s);

   704 

   705     /* Set the default configuration parameters:

   706      */

   707     s->max_lazy_match   = configuration_table[s->level].max_lazy;

   708     s->good_match       = configuration_table[s->level].good_length;

   709     s->nice_match       = configuration_table[s->level].nice_length;

   710     s->max_chain_length = configuration_table[s->level].max_chain;

   711 

   712     s->strstart = 0;

   713     s->block_start = 0L;

   714     s->lookahead = 0;

   715     s->match_length = s->prev_length = MIN_MATCH-1;

   716     s->match_available = 0;

   717     s->ins_h = 0;

   718 #ifdef ASMV

   719     match_init(); /* initialize the asm code */

   720 #endif

   721 }

   722 

   723 /* ===========================================================================

   724  * Set match_start to the longest match starting at the given string and

   725  * return its length. Matches shorter or equal to prev_length are discarded,

   726  * in which case the result is equal to prev_length and match_start is

   727  * garbage.

   728  * IN assertions: cur_match is the head of the hash chain for the current

   729  *   string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1

   730  * OUT assertion: the match length is not greater than s->lookahead.

   731  */

   732 #ifndef ASMV

   733 /* For 80x86 and 680x0, an optimized version will be provided in match.asm or

   734  * match.S. The code will be functionally equivalent.

   735  */

   736 #ifndef FASTEST

   737 local uInt longest_match(

   738     deflate_state *s,

   739     IPos cur_match)                         /* current match */

   740 {

   741     unsigned chain_length = s->max_chain_length;/* max hash chain length */

   742     register Bytef *scan = s->window + s->strstart; /* current string */

   743     register Bytef *match;                       /* matched string */

   744     register int len;                           /* length of current match */

   745     int best_len = s->prev_length;              /* best match length so far */

   746     int nice_match = s->nice_match;             /* stop if match long enough */

   747     IPos limit = s->strstart > (IPos)MAX_DIST(s) ?

   748         s->strstart - (IPos)MAX_DIST(s) : NIL;

   749     /* Stop when cur_match becomes <= limit. To simplify the code,

   750      * we prevent matches with the string of window index 0.

   751      */

   752     Posf *prev = s->prev;

   753     uInt wmask = s->w_mask;

   754 

   755 #ifdef UNALIGNED_OK

   756     /* Compare two bytes at a time. Note: this is not always beneficial.

   757      * Try with and without -DUNALIGNED_OK to check.

   758      */

   759     register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1;

   760     register ush scan_start = *(ushf*)scan;

   761     register ush scan_end   = *(ushf*)(scan+best_len-1);

   762 #else

   763     register Bytef *strend = s->window + s->strstart + MAX_MATCH;

   764     register Byte scan_end1  = scan[best_len-1];

   765     register Byte scan_end   = scan[best_len];

   766 #endif

   767 

   768     /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.

   769      * It is easy to get rid of this optimization if necessary.

   770      */

   771     Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");

   772 

   773     /* Do not waste too much time if we already have a good match: */

   774     if (s->prev_length >= s->good_match) {

   775         chain_length >>= 2;

   776     }

   777     /* Do not look for matches beyond the end of the input. This is necessary

   778      * to make deflate deterministic.

   779      */

   780     if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead;

   781 

   782     Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");

   783 

   784     do {

   785         Assert(cur_match < s->strstart, "no future");

   786         match = s->window + cur_match;

   787 

   788         /* Skip to next match if the match length cannot increase

   789          * or if the match length is less than 2:

   790          */

   791 #if (defined(UNALIGNED_OK) && MAX_MATCH == 258)

   792         /* This code assumes sizeof(unsigned short) == 2. Do not use

   793          * UNALIGNED_OK if your compiler uses a different size.

   794          */

   795         if (*(ushf*)(match+best_len-1) != scan_end ||

   796             *(ushf*)match != scan_start) continue;

   797 

   798         /* It is not necessary to compare scan[2] and match[2] since they are

   799          * always equal when the other bytes match, given that the hash keys

   800          * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at

   801          * strstart+3, +5, ... up to strstart+257. We check for insufficient

   802          * lookahead only every 4th comparison; the 128th check will be made

   803          * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is

   804          * necessary to put more guard bytes at the end of the window, or

   805          * to check more often for insufficient lookahead.

   806          */

   807         Assert(scan[2] == match[2], "scan[2]?");

   808         scan++, match++;

   809         do {

   810         } while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) &&

   811                  *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&

   812                  *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&

   813                  *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&

   814                  scan < strend);

   815         /* The funny "do {}" generates better code on most compilers */

   816 

   817         /* Here, scan <= window+strstart+257 */

   818         Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");

   819         if (*scan == *match) scan++;

   820 

   821         len = (MAX_MATCH - 1) - (int)(strend-scan);

   822         scan = strend - (MAX_MATCH-1);

   823 

   824 #else /* UNALIGNED_OK */

   825 

   826         if (match[best_len]   != scan_end  ||

   827             match[best_len-1] != scan_end1 ||

   828             *match            != *scan     ||

   829             *++match          != scan[1])      continue;

   830 

   831         /* The check at best_len-1 can be removed because it will be made

   832          * again later. (This heuristic is not always a win.)

   833          * It is not necessary to compare scan[2] and match[2] since they

   834          * are always equal when the other bytes match, given that

   835          * the hash keys are equal and that HASH_BITS >= 8.

   836          */

   837         scan += 2, match++;

   838         Assert(*scan == *match, "match[2]?");

   839 

   840         /* We check for insufficient lookahead only every 8th comparison;

   841          * the 256th check will be made at strstart+258.

   842          */

   843         do {

   844         } while (*++scan == *++match && *++scan == *++match &&

   845                  *++scan == *++match && *++scan == *++match &&

   846                  *++scan == *++match && *++scan == *++match &&

   847                  *++scan == *++match && *++scan == *++match &&

   848                  scan < strend);

   849 

   850         Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");

   851 

   852         len = MAX_MATCH - (int)(strend - scan);

   853         scan = strend - MAX_MATCH;

   854 

   855 #endif /* UNALIGNED_OK */

   856 

   857         if (len > best_len) {

   858             s->match_start = cur_match;

   859             best_len = len;

   860             if (len >= nice_match) break;

   861 #ifdef UNALIGNED_OK

   862             scan_end = *(ushf*)(scan+best_len-1);

   863 #else

   864             scan_end1  = scan[best_len-1];

   865             scan_end   = scan[best_len];

   866 #endif

   867         }

   868     } while ((cur_match = prev[cur_match & wmask]) > limit

   869              && --chain_length != 0);

   870 

   871     if ((uInt)best_len <= s->lookahead) return (uInt)best_len;

   872     return s->lookahead;

   873 }

   874 

   875 #else /* FASTEST */

   876 /* ---------------------------------------------------------------------------

   877  * Optimized version for level == 1 only

   878  */

   879 local uInt longest_match(

   880     deflate_state *s,

   881     IPos cur_match)                           /* current match */

   882 {

   883     register Bytef *scan = s->window + s->strstart; /* current string */

   884     register Bytef *match;                       /* matched string */

   885     register int len;                           /* length of current match */

   886     register Bytef *strend = s->window + s->strstart + MAX_MATCH;

   887 

   888     /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.

   889      * It is easy to get rid of this optimization if necessary.

   890      */

   891     Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");

   892 

   893     Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");

   894 

   895     Assert(cur_match < s->strstart, "no future");

   896 

   897     match = s->window + cur_match;

   898 

   899     /* Return failure if the match length is less than 2:

   900      */

   901     if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1;

   902 

   903     /* The check at best_len-1 can be removed because it will be made

   904      * again later. (This heuristic is not always a win.)

   905      * It is not necessary to compare scan[2] and match[2] since they

   906      * are always equal when the other bytes match, given that

   907      * the hash keys are equal and that HASH_BITS >= 8.

   908      */

   909     scan += 2, match += 2;

   910     Assert(*scan == *match, "match[2]?");

   911 

   912     /* We check for insufficient lookahead only every 8th comparison;

   913      * the 256th check will be made at strstart+258.

   914      */

   915     do {

   916     } while (*++scan == *++match && *++scan == *++match &&

   917 	     *++scan == *++match && *++scan == *++match &&

   918 	     *++scan == *++match && *++scan == *++match &&

   919 	     *++scan == *++match && *++scan == *++match &&

   920 	     scan < strend);

   921 

   922     Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");

   923 

   924     len = MAX_MATCH - (int)(strend - scan);

   925 

   926     if (len < MIN_MATCH) return MIN_MATCH - 1;

   927 

   928     s->match_start = cur_match;

   929     return len <= s->lookahead ? len : s->lookahead;

   930 }

   931 #endif /* FASTEST */

   932 #endif /* ASMV */

   933 

   934 #ifdef DEBUG

   935 /* ===========================================================================

   936  * Check that the match at match_start is indeed a match.

   937  */

   938 local void check_match(

   939     deflate_state *s,

   940     IPos start, match,

   941     int length)

   942 {

   943     /* check that the match is indeed a match */

   944     if (zmemcmp(s->window + match,

   945                 s->window + start, length) != EQUAL) {

   946         fprintf(stderr, " start %u, match %u, length %d\n",

   947 		start, match, length);

   948         do {

   949 	    fprintf(stderr, "%c%c", s->window[match++], s->window[start++]);

   950 	} while (--length != 0);

   951         z_error("invalid match");

   952     }

   953     if (z_verbose > 1) {

   954         fprintf(stderr,"\\[%d,%d]", start-match, length);

   955         do { putc(s->window[start++], stderr); } while (--length != 0);

   956     }

   957 }

   958 #else

   959 #  define check_match(s, start, match, length)

   960 #endif

   961 

   962 /* ===========================================================================

   963  * Fill the window when the lookahead becomes insufficient.

   964  * Updates strstart and lookahead.

   965  *

   966  * IN assertion: lookahead < MIN_LOOKAHEAD

   967  * OUT assertions: strstart <= window_size-MIN_LOOKAHEAD

   968  *    At least one byte has been read, or avail_in == 0; reads are

   969  *    performed for at least two bytes (required for the zip translate_eol

   970  *    option -- not supported here).

   971  */

   972 local void fill_window(

   973     deflate_state *s)

   974 {

   975     register unsigned n, m;

   976     register Posf *p;

   977     unsigned more;    /* Amount of free space at the end of the window. */

   978     uInt wsize = s->w_size;

   979 

   980     do {

   981         more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart);

   982 

   983         /* Deal with !@#$% 64K limit: */

   984         if (more == 0 && s->strstart == 0 && s->lookahead == 0) {

   985             more = wsize;

   986 

   987         } else if (more == (unsigned)(-1)) {

   988             /* Very unlikely, but possible on 16 bit machine if strstart == 0

   989              * and lookahead == 1 (input done one byte at time)

   990              */

   991             more--;

   992 

   993         /* If the window is almost full and there is insufficient lookahead,

   994          * move the upper half to the lower one to make room in the upper half.

   995          */

   996         } else if (s->strstart >= wsize+MAX_DIST(s)) {

   997 

   998             zmemcpy(s->window, s->window+wsize, (unsigned)wsize);

   999             s->match_start -= wsize;

  1000             s->strstart    -= wsize; /* we now have strstart >= MAX_DIST */

  1001             s->block_start -= (long) wsize;

  1002 

  1003             /* Slide the hash table (could be avoided with 32 bit values

  1004                at the expense of memory usage). We slide even when level == 0

  1005                to keep the hash table consistent if we switch back to level > 0

  1006                later. (Using level 0 permanently is not an optimal usage of

  1007                zlib, so we don't care about this pathological case.)

  1008              */

  1009 	    n = s->hash_size;

  1010 	    p = &s->head[n];

  1011 	    do {

  1012 		m = *--p;

  1013 		*p = (Pos)(m >= wsize ? m-wsize : NIL);

  1014 	    } while (--n);

  1015 

  1016 	    n = wsize;

  1017 #ifndef FASTEST

  1018 	    p = &s->prev[n];

  1019 	    do {

  1020 		m = *--p;

  1021 		*p = (Pos)(m >= wsize ? m-wsize : NIL);

  1022 		/* If n is not on any hash chain, prev[n] is garbage but

  1023 		 * its value will never be used.

  1024 		 */

  1025 	    } while (--n);

  1026 #endif

  1027             more += wsize;

  1028         }

  1029         if (s->strm->avail_in == 0) return;

  1030 

  1031         /* If there was no sliding:

  1032          *    strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 &&

  1033          *    more == window_size - lookahead - strstart

  1034          * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1)

  1035          * => more >= window_size - 2*WSIZE + 2

  1036          * In the BIG_MEM or MMAP case (not yet supported),

  1037          *   window_size == input_size + MIN_LOOKAHEAD  &&

  1038          *   strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD.

  1039          * Otherwise, window_size == 2*WSIZE so more >= 2.

  1040          * If there was sliding, more >= WSIZE. So in all cases, more >= 2.

  1041          */

  1042         Assert(more >= 2, "more < 2");

  1043 

  1044         n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more);

  1045         s->lookahead += n;

  1046 

  1047         /* Initialize the hash value now that we have some input: */

  1048         if (s->lookahead >= MIN_MATCH) {

  1049             s->ins_h = s->window[s->strstart];

  1050             UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);

  1051 #if MIN_MATCH != 3

  1052 //            Call UPDATE_HASH() MIN_MATCH-3 more times

  1053 #endif

  1054         }

  1055         /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage,

  1056          * but this is not important since only literal bytes will be emitted.

  1057          */

  1058 

  1059     } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0);

  1060 }

  1061 

  1062 /* ===========================================================================

  1063  * Flush the current block, with given end-of-file flag.

  1064  * IN assertion: strstart is set to the end of the current match.

  1065  */

  1066 #define FLUSH_BLOCK_ONLY(s, eof) { \

  1067    _tr_flush_block(s, (s->block_start >= 0L ? \

  1068                    (charf *)&s->window[(unsigned)s->block_start] : \

  1069                    (charf *)Z_NULL), \

  1070 		(ulg)((long)s->strstart - s->block_start), \

  1071 		(eof)); \

  1072    s->block_start = s->strstart; \

  1073    flush_pending(s->strm); \

  1074    Tracev((stderr,"[FLUSH]")); \

  1075 }

  1076 

  1077 /* Same but force premature exit if necessary. */

  1078 #define FLUSH_BLOCK(s, eof) { \

  1079    FLUSH_BLOCK_ONLY(s, eof); \

  1080    if (s->strm->avail_out == 0) return (eof) ? finish_started : need_more; \

  1081 }

  1082 

  1083 /* ===========================================================================

  1084  * Copy without compression as much as possible from the input stream, return

  1085  * the current block state.

  1086  * This function does not insert new strings in the dictionary since

  1087  * uncompressible data is probably not useful. This function is used

  1088  * only for the level=0 compression option.

  1089  * NOTE: this function should be optimized to avoid extra copying from

  1090  * window to pending_buf.

  1091  */

  1092 local block_state deflate_stored(

  1093     deflate_state *s,

  1094     int flush)

  1095 {

  1096     /* Stored blocks are limited to 0xffff bytes, pending_buf is limited

  1097      * to pending_buf_size, and each stored block has a 5 byte header:

  1098      */

  1099     ulg max_block_size = 0xffff;

  1100     ulg max_start;

  1101 

  1102     if (max_block_size > s->pending_buf_size - 5) {

  1103         max_block_size = s->pending_buf_size - 5;

  1104     }

  1105 

  1106     /* Copy as much as possible from input to output: */

  1107     for (;;) {

  1108         /* Fill the window as much as possible: */

  1109         if (s->lookahead <= 1) {

  1110 

  1111             Assert(s->strstart < s->w_size+MAX_DIST(s) ||

  1112 		   s->block_start >= (long)s->w_size, "slide too late");

  1113 

  1114             fill_window(s);

  1115             if (s->lookahead == 0 && flush == Z_NO_FLUSH) return need_more;

  1116 

  1117             if (s->lookahead == 0) break; /* flush the current block */

  1118         }

  1119 	Assert(s->block_start >= 0L, "block gone");

  1120 

  1121 	s->strstart += s->lookahead;

  1122 	s->lookahead = 0;

  1123 

  1124 	/* Emit a stored block if pending_buf will be full: */

  1125  	max_start = s->block_start + max_block_size;

  1126         if (s->strstart == 0 || (ulg)s->strstart >= max_start) {

  1127 	    /* strstart == 0 is possible when wraparound on 16-bit machine */

  1128 	    s->lookahead = (uInt)(s->strstart - max_start);

  1129 	    s->strstart = (uInt)max_start;

  1130             FLUSH_BLOCK(s, 0);

  1131 	}

  1132 	/* Flush if we may have to slide, otherwise block_start may become

  1133          * negative and the data will be gone:

  1134          */

  1135         if (s->strstart - (uInt)s->block_start >= MAX_DIST(s)) {