1 /*

     2  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     3  *

     4  * This code is free software; you can redistribute it and/or modify it

     5  * under the terms of the GNU General Public License version 2 only, as

     6  * published by the Free Software Foundation.  Oracle designates this

     7  * particular file as subject to the "Classpath" exception as provided

     8  * by Oracle in the LICENSE file that accompanied this code.

     9  *

    10  * This code is distributed in the hope that it will be useful, but WITHOUT

    11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    13  * version 2 for more details (a copy is included in the LICENSE file that

    14  * accompanied this code).

    15  *

    16  * You should have received a copy of the GNU General Public License version

    17  * 2 along with this work; if not, write to the Free Software Foundation,

    18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    19  *

    20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    21  * or visit www.oracle.com if you need additional information or have any

    22  * questions.

    23  */

    24 

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

    26  * Copyright (C) 1995-2010 Jean-loup Gailly and Mark Adler

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

    28  */

    29 

    30 /*

    31  *  ALGORITHM

    32  *

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

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

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

    36  *

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

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

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

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

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

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

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

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

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

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

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

    48  *      (by Leonid Broukhis).

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

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

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

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

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

    54  *

    55  *  ACKNOWLEDGEMENTS

    56  *

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

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

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

    60  *

    61  *  REFERENCES

    62  *

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

    64  *      Available in http://www.ietf.org/rfc/rfc1951.txt

    65  *

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

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

    68  *

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

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

    71  *

    72  */

    73 

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

    75 

    76 #include "deflate.h"

    77 

    78 const char deflate_copyright[] =

    79    " deflate 1.2.5 Copyright 1995-2010 Jean-loup Gailly and Mark Adler ";

    80 /*

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

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

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

    84   copyright string in the executable of your product.

    85  */

    86 

    87 /* ===========================================================================

    88  *  Function prototypes.

    89  */

    90 typedef enum {

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

    92     block_done,     /* block flush performed */

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

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

    95 } block_state;

    96 

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

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

    99 

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

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

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

   103 #ifndef FASTEST

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

   105 #endif

   106 local block_state deflate_rle    OF((deflate_state *s, int flush));

   107 local block_state deflate_huff   OF((deflate_state *s, int flush));

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

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

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

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

   112 #ifdef ASMV

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

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

   115 #else

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

   117 #endif

   118 

   119 #ifdef DEBUG

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

   121                             int length));

   122 #endif

   123 

   124 /* ===========================================================================

   125  * Local data

   126  */

   127 

   128 #define NIL 0

   129 /* Tail of hash chains */

   130 

   131 #ifndef TOO_FAR

   132 #  define TOO_FAR 4096

   133 #endif

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

   135 

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

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

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

   139  * found for specific files.

   140  */

   141 typedef struct config_s {

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

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

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

   145    ush max_chain;

   146    compress_func func;

   147 } config;

   148 

   149 #ifdef FASTEST

   150 local const config configuration_table[2] = {

   151 /*      good lazy nice chain */

   152 /* 0 */ {0,    0,  0,    0, deflate_stored},  /* store only */

   153 /* 1 */ {4,    4,  8,    4, deflate_fast}}; /* max speed, no lazy matches */

   154 #else

   155 local const config configuration_table[10] = {

   156 /*      good lazy nice chain */

   157 /* 0 */ {0,    0,  0,    0, deflate_stored},  /* store only */

   158 /* 1 */ {4,    4,  8,    4, deflate_fast}, /* max speed, no lazy matches */

   159 /* 2 */ {4,    5, 16,    8, deflate_fast},

   160 /* 3 */ {4,    6, 32,   32, deflate_fast},

   161 

   162 /* 4 */ {4,    4, 16,   16, deflate_slow},  /* lazy matches */

   163 /* 5 */ {8,   16, 32,   32, deflate_slow},

   164 /* 6 */ {8,   16, 128, 128, deflate_slow},

   165 /* 7 */ {8,   32, 128, 256, deflate_slow},

   166 /* 8 */ {32, 128, 258, 1024, deflate_slow},

   167 /* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* max compression */

   168 #endif

   169 

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

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

   172  * meaning.

   173  */

   174 

   175 #define EQUAL 0

   176 /* result of memcmp for equal strings */

   177 

   178 #ifndef NO_DUMMY_DECL

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

   180 #endif

   181 

   182 /* ===========================================================================

   183  * Update a hash value with the given input byte

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

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

   186  *    previous key instead of complete recalculation each time.

   187  */

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

   189 

   190 

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

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

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

   194  * the previous length of the hash chain.

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

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

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

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

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

   200  */

   201 #ifdef FASTEST

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

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

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

   205     s->head[s->ins_h] = (Pos)(str))

   206 #else

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

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

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

   210     s->head[s->ins_h] = (Pos)(str))

   211 #endif

   212 

   213 /* ===========================================================================

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

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

   216  */

   217 #define CLEAR_HASH(s) \

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

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

   220 

   221 /* ========================================================================= */

   222 int ZEXPORT deflateInit_(strm, level, version, stream_size)

   223     z_streamp strm;

   224     int level;

   225     const char *version;

   226     int stream_size;

   227 {

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

   229                          Z_DEFAULT_STRATEGY, version, stream_size);

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

   231 }

   232 

   233 /* ========================================================================= */

   234 int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy,

   235                   version, stream_size)

   236     z_streamp strm;

   237     int  level;

   238     int  method;

   239     int  windowBits;

   240     int  memLevel;

   241     int  strategy;

   242     const char *version;

   243     int stream_size;

   244 {

   245     deflate_state *s;

   246     int wrap = 1;

   247     static const char my_version[] = ZLIB_VERSION;

   248 

   249     ushf *overlay;

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

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

   252      */

   253 

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

   255         stream_size != sizeof(z_stream)) {

   256         return Z_VERSION_ERROR;

   257     }

   258     if (strm == Z_NULL) return Z_STREAM_ERROR;

   259 

   260     strm->msg = Z_NULL;

   261     if (strm->zalloc == (alloc_func)0) {

   262         strm->zalloc = zcalloc;

   263         strm->opaque = (voidpf)0;

   264     }

   265     if (strm->zfree == (free_func)0) strm->zfree = zcfree;

   266 

   267 #ifdef FASTEST

   268     if (level != 0) level = 1;

   269 #else

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

   271 #endif

   272 

   273     if (windowBits < 0) { /* suppress zlib wrapper */

   274         wrap = 0;

   275         windowBits = -windowBits;

   276     }

   277 #ifdef GZIP

   278     else if (windowBits > 15) {

   279         wrap = 2;       /* write gzip wrapper instead */

   280         windowBits -= 16;

   281     }

   282 #endif

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

   284         windowBits < 8 || windowBits > 15 || level < 0 || level > 9 ||

   285         strategy < 0 || strategy > Z_FIXED) {

   286         return Z_STREAM_ERROR;

   287     }

   288     if (windowBits == 8) windowBits = 9;  /* until 256-byte window bug fixed */

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

   290     if (s == Z_NULL) return Z_MEM_ERROR;

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

   292     s->strm = strm;

   293 

   294     s->wrap = wrap;

   295     s->gzhead = Z_NULL;

   296     s->w_bits = windowBits;

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

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

   299 

   300     s->hash_bits = memLevel + 7;

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

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

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

   304 

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

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

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

   308 

   309     s->high_water = 0;      /* nothing written to s->window yet */

   310 

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

   312 

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

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

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

   316 

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

   318         s->pending_buf == Z_NULL) {

   319         s->status = FINISH_STATE;

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

   321         deflateEnd (strm);

   322         return Z_MEM_ERROR;

   323     }

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

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

   326 

   327     s->level = level;

   328     s->strategy = strategy;

   329     s->method = (Byte)method;

   330 

   331     return deflateReset(strm);

   332 }

   333 

   334 /* ========================================================================= */

   335 int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength)

   336     z_streamp strm;

   337     const Bytef *dictionary;

   338     uInt  dictLength;

   339 {

   340     deflate_state *s;

   341     uInt length = dictLength;

   342     uInt n;

   343     IPos hash_head = 0;

   344 

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

   346         strm->state->wrap == 2 ||

   347         (strm->state->wrap == 1 && strm->state->status != INIT_STATE))

   348         return Z_STREAM_ERROR;

   349 

   350     s = strm->state;

   351     if (s->wrap)

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

   353 

   354     if (length < MIN_MATCH) return Z_OK;

   355     if (length > s->w_size) {

   356         length = s->w_size;

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

   358     }

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

   360     s->strstart = length;

   361     s->block_start = (long)length;

   362 

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

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

   365      * call of fill_window.

   366      */

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

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

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

   370         INSERT_STRING(s, n, hash_head);

   371     }

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

   373     return Z_OK;

   374 }

   375 

   376 /* ========================================================================= */

   377 int ZEXPORT deflateReset (strm)

   378     z_streamp strm;

   379 {

   380     deflate_state *s;

   381 

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

   383         strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0) {

   384         return Z_STREAM_ERROR;

   385     }

   386 

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

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

   389     strm->data_type = Z_UNKNOWN;

   390 

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

   392     s->pending = 0;

   393     s->pending_out = s->pending_buf;

   394 

   395     if (s->wrap < 0) {

   396         s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */

   397     }

   398     s->status = s->wrap ? INIT_STATE : BUSY_STATE;

   399     strm->adler =

   400 #ifdef GZIP

   401         s->wrap == 2 ? crc32(0L, Z_NULL, 0) :

   402 #endif

   403         adler32(0L, Z_NULL, 0);

   404     s->last_flush = Z_NO_FLUSH;

   405 

   406     _tr_init(s);

   407     lm_init(s);

   408 

   409     return Z_OK;

   410 }

   411 

   412 /* ========================================================================= */

   413 int ZEXPORT deflateSetHeader (strm, head)

   414     z_streamp strm;

   415     gz_headerp head;

   416 {

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

   418     if (strm->state->wrap != 2) return Z_STREAM_ERROR;

   419     strm->state->gzhead = head;

   420     return Z_OK;

   421 }

   422 

   423 /* ========================================================================= */

   424 int ZEXPORT deflatePrime (strm, bits, value)

   425     z_streamp strm;

   426     int bits;

   427     int value;

   428 {

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

   430     strm->state->bi_valid = bits;

   431     strm->state->bi_buf = (ush)(value & ((1 << bits) - 1));

   432     return Z_OK;

   433 }

   434 

   435 /* ========================================================================= */

   436 int ZEXPORT deflateParams(strm, level, strategy)

   437     z_streamp strm;

   438     int level;

   439     int strategy;

   440 {

   441     deflate_state *s;

   442     compress_func func;

   443     int err = Z_OK;

   444 

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

   446     s = strm->state;

   447 

   448 #ifdef FASTEST

   449     if (level != 0) level = 1;

   450 #else

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

   452 #endif

   453     if (level < 0 || level > 9 || strategy < 0 || strategy > Z_FIXED) {

   454         return Z_STREAM_ERROR;

   455     }

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

   457 

   458     if ((strategy != s->strategy || func != configuration_table[level].func) &&

   459         strm->total_in != 0) {

   460         /* Flush the last buffer: */

   461         err = deflate(strm, Z_BLOCK);

   462     }

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

   464         s->level = level;

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

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

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

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

   469     }

   470     s->strategy = strategy;

   471     return err;

   472 }

   473 

   474 /* ========================================================================= */

   475 int ZEXPORT deflateTune(strm, good_length, max_lazy, nice_length, max_chain)

   476     z_streamp strm;

   477     int good_length;

   478     int max_lazy;

   479     int nice_length;

   480     int max_chain;

   481 {

   482     deflate_state *s;

   483 

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

   485     s = strm->state;

   486     s->good_match = good_length;

   487     s->max_lazy_match = max_lazy;

   488     s->nice_match = nice_length;

   489     s->max_chain_length = max_chain;

   490     return Z_OK;

   491 }

   492 

   493 /* =========================================================================

   494  * For the default windowBits of 15 and memLevel of 8, this function returns

   495  * a close to exact, as well as small, upper bound on the compressed size.

   496  * They are coded as constants here for a reason--if the #define's are

   497  * changed, then this function needs to be changed as well.  The return

   498  * value for 15 and 8 only works for those exact settings.

   499  *

   500  * For any setting other than those defaults for windowBits and memLevel,

   501  * the value returned is a conservative worst case for the maximum expansion

   502  * resulting from using fixed blocks instead of stored blocks, which deflate

   503  * can emit on compressed data for some combinations of the parameters.

   504  *

   505  * This function could be more sophisticated to provide closer upper bounds for

   506  * every combination of windowBits and memLevel.  But even the conservative

   507  * upper bound of about 14% expansion does not seem onerous for output buffer

   508  * allocation.

   509  */

   510 uLong ZEXPORT deflateBound(strm, sourceLen)

   511     z_streamp strm;

   512     uLong sourceLen;

   513 {

   514     deflate_state *s;

   515     uLong complen, wraplen;

   516     Bytef *str;

   517 

   518     /* conservative upper bound for compressed data */

   519     complen = sourceLen +

   520               ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 5;

   521 

   522     /* if can't get parameters, return conservative bound plus zlib wrapper */

   523     if (strm == Z_NULL || strm->state == Z_NULL)

   524         return complen + 6;

   525 

   526     /* compute wrapper length */

   527     s = strm->state;

   528     switch (s->wrap) {

   529     case 0:                                 /* raw deflate */

   530         wraplen = 0;

   531         break;

   532     case 1:                                 /* zlib wrapper */

   533         wraplen = 6 + (s->strstart ? 4 : 0);

   534         break;

   535     case 2:                                 /* gzip wrapper */

   536         wraplen = 18;

   537         if (s->gzhead != Z_NULL) {          /* user-supplied gzip header */

   538             if (s->gzhead->extra != Z_NULL)

   539                 wraplen += 2 + s->gzhead->extra_len;

   540             str = s->gzhead->name;

   541             if (str != Z_NULL)

   542                 do {

   543                     wraplen++;

   544                 } while (*str++);

   545             str = s->gzhead->comment;

   546             if (str != Z_NULL)

   547                 do {

   548                     wraplen++;

   549                 } while (*str++);

   550             if (s->gzhead->hcrc)

   551                 wraplen += 2;

   552         }

   553         break;

   554     default:                                /* for compiler happiness */

   555         wraplen = 6;

   556     }

   557 

   558     /* if not default parameters, return conservative bound */

   559     if (s->w_bits != 15 || s->hash_bits != 8 + 7)

   560         return complen + wraplen;

   561 

   562     /* default settings: return tight bound for that case */

   563     return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) +

   564            (sourceLen >> 25) + 13 - 6 + wraplen;

   565 }

   566 

   567 /* =========================================================================

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

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

   570  * pending_buf.

   571  */

   572 local void putShortMSB (s, b)

   573     deflate_state *s;

   574     uInt b;

   575 {

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

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

   578 }

   579 

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

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

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

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

   584  * (See also read_buf()).

   585  */

   586 local void flush_pending(strm)

   587     z_streamp strm;

   588 {

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

   590 

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

   592     if (len == 0) return;

   593 

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

   595     strm->next_out  += len;

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

   597     strm->total_out += len;

   598     strm->avail_out  -= len;

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

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

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

   602     }

   603 }

   604 

   605 /* ========================================================================= */

   606 int ZEXPORT deflate (strm, flush)

   607     z_streamp strm;

   608     int flush;

   609 {

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

   611     deflate_state *s;

   612 

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

   614         flush > Z_BLOCK || flush < 0) {

   615         return Z_STREAM_ERROR;

   616     }

   617     s = strm->state;

   618 

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

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

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

   622         ERR_RETURN(strm, Z_STREAM_ERROR);

   623     }

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

   625 

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

   627     old_flush = s->last_flush;

   628     s->last_flush = flush;

   629 

   630     /* Write the header */

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

   632 #ifdef GZIP

   633         if (s->wrap == 2) {

   634             strm->adler = crc32(0L, Z_NULL, 0);

   635             put_byte(s, 31);

   636             put_byte(s, 139);

   637             put_byte(s, 8);

   638             if (s->gzhead == Z_NULL) {

   639                 put_byte(s, 0);

   640                 put_byte(s, 0);

   641                 put_byte(s, 0);

   642                 put_byte(s, 0);

   643                 put_byte(s, 0);

   644                 put_byte(s, s->level == 9 ? 2 :

   645                             (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?

   646                              4 : 0));

   647                 put_byte(s, OS_CODE);

   648                 s->status = BUSY_STATE;

   649             }

   650             else {

   651                 put_byte(s, (s->gzhead->text ? 1 : 0) +

   652                             (s->gzhead->hcrc ? 2 : 0) +

   653                             (s->gzhead->extra == Z_NULL ? 0 : 4) +

   654                             (s->gzhead->name == Z_NULL ? 0 : 8) +

   655                             (s->gzhead->comment == Z_NULL ? 0 : 16)

   656                         );

   657                 put_byte(s, (Byte)(s->gzhead->time & 0xff));

   658                 put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff));

   659                 put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff));

   660                 put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff));

   661                 put_byte(s, s->level == 9 ? 2 :

   662                             (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?

   663                              4 : 0));

   664                 put_byte(s, s->gzhead->os & 0xff);

   665                 if (s->gzhead->extra != Z_NULL) {

   666                     put_byte(s, s->gzhead->extra_len & 0xff);

   667                     put_byte(s, (s->gzhead->extra_len >> 8) & 0xff);

   668                 }

   669                 if (s->gzhead->hcrc)

   670                     strm->adler = crc32(strm->adler, s->pending_buf,

   671                                         s->pending);

   672                 s->gzindex = 0;

   673                 s->status = EXTRA_STATE;

   674             }

   675         }

   676         else

   677 #endif

   678         {

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

   680             uInt level_flags;

   681 

   682             if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2)

   683                 level_flags = 0;

   684             else if (s->level < 6)

   685                 level_flags = 1;

   686             else if (s->level == 6)

   687                 level_flags = 2;

   688             else

   689                 level_flags = 3;

   690             header |= (level_flags << 6);

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

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

   693 

   694             s->status = BUSY_STATE;

   695             putShortMSB(s, header);

   696 

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

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

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

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

   701             }

   702             strm->adler = adler32(0L, Z_NULL, 0);

   703         }

   704     }

   705 #ifdef GZIP

   706     if (s->status == EXTRA_STATE) {

   707         if (s->gzhead->extra != Z_NULL) {

   708             uInt beg = s->pending;  /* start of bytes to update crc */

   709 

   710             while (s->gzindex < (s->gzhead->extra_len & 0xffff)) {

   711                 if (s->pending == s->pending_buf_size) {

   712                     if (s->gzhead->hcrc && s->pending > beg)

   713                         strm->adler = crc32(strm->adler, s->pending_buf + beg,

   714                                             s->pending - beg);

   715                     flush_pending(strm);

   716                     beg = s->pending;

   717                     if (s->pending == s->pending_buf_size)

   718                         break;

   719                 }

   720                 put_byte(s, s->gzhead->extra[s->gzindex]);

   721                 s->gzindex++;

   722             }

   723             if (s->gzhead->hcrc && s->pending > beg)

   724                 strm->adler = crc32(strm->adler, s->pending_buf + beg,

   725                                     s->pending - beg);

   726             if (s->gzindex == s->gzhead->extra_len) {

   727                 s->gzindex = 0;

   728                 s->status = NAME_STATE;

   729             }

   730         }

   731         else

   732             s->status = NAME_STATE;

   733     }

   734     if (s->status == NAME_STATE) {

   735         if (s->gzhead->name != Z_NULL) {

   736             uInt beg = s->pending;  /* start of bytes to update crc */

   737             int val;

   738 

   739             do {

   740                 if (s->pending == s->pending_buf_size) {

   741                     if (s->gzhead->hcrc && s->pending > beg)

   742                         strm->adler = crc32(strm->adler, s->pending_buf + beg,

   743                                             s->pending - beg);

   744                     flush_pending(strm);

   745                     beg = s->pending;

   746                     if (s->pending == s->pending_buf_size) {

   747                         val = 1;

   748                         break;

   749                     }

   750                 }

   751                 val = s->gzhead->name[s->gzindex++];

   752                 put_byte(s, val);

   753             } while (val != 0);

   754             if (s->gzhead->hcrc && s->pending > beg)

   755                 strm->adler = crc32(strm->adler, s->pending_buf + beg,

   756                                     s->pending - beg);

   757             if (val == 0) {

   758                 s->gzindex = 0;

   759                 s->status = COMMENT_STATE;

   760             }

   761         }

   762         else

   763             s->status = COMMENT_STATE;

   764     }

   765     if (s->status == COMMENT_STATE) {

   766         if (s->gzhead->comment != Z_NULL) {

   767             uInt beg = s->pending;  /* start of bytes to update crc */

   768             int val;

   769 

   770             do {

   771                 if (s->pending == s->pending_buf_size) {

   772                     if (s->gzhead->hcrc && s->pending > beg)

   773                         strm->adler = crc32(strm->adler, s->pending_buf + beg,

   774                                             s->pending - beg);

   775                     flush_pending(strm);

   776                     beg = s->pending;

   777                     if (s->pending == s->pending_buf_size) {

   778                         val = 1;

   779                         break;

   780                     }

   781                 }

   782                 val = s->gzhead->comment[s->gzindex++];

   783                 put_byte(s, val);

   784             } while (val != 0);

   785             if (s->gzhead->hcrc && s->pending > beg)

   786                 strm->adler = crc32(strm->adler, s->pending_buf + beg,

   787                                     s->pending - beg);

   788             if (val == 0)

   789                 s->status = HCRC_STATE;

   790         }

   791         else

   792             s->status = HCRC_STATE;

   793     }

   794     if (s->status == HCRC_STATE) {

   795         if (s->gzhead->hcrc) {

   796             if (s->pending + 2 > s->pending_buf_size)

   797                 flush_pending(strm);

   798             if (s->pending + 2 <= s->pending_buf_size) {

   799                 put_byte(s, (Byte)(strm->adler & 0xff));

   800                 put_byte(s, (Byte)((strm->adler >> 8) & 0xff));

   801                 strm->adler = crc32(0L, Z_NULL, 0);

   802                 s->status = BUSY_STATE;

   803             }

   804         }

   805         else

   806             s->status = BUSY_STATE;

   807     }

   808 #endif

   809 

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

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

   812         flush_pending(strm);

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

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

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

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

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

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

   819              */

   820             s->last_flush = -1;

   821             return Z_OK;

   822         }

   823 

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

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

   826      * returning Z_STREAM_END instead of Z_BUF_ERROR.

   827      */

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

   829                flush != Z_FINISH) {

   830         ERR_RETURN(strm, Z_BUF_ERROR);

   831     }

   832 

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

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

   835         ERR_RETURN(strm, Z_BUF_ERROR);

   836     }

   837 

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

   839      */

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

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

   842         block_state bstate;

   843 

   844         bstate = s->strategy == Z_HUFFMAN_ONLY ? deflate_huff(s, flush) :

   845                     (s->strategy == Z_RLE ? deflate_rle(s, flush) :

   846                         (*(configuration_table[s->level].func))(s, flush));

   847 

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

   849             s->status = FINISH_STATE;

   850         }

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

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

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

   854             }

   855             return Z_OK;

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

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

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

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

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

   861              * one empty block.

   862              */

   863         }

   864         if (bstate == block_done) {

   865             if (flush == Z_PARTIAL_FLUSH) {

   866                 _tr_align(s);

   867             } else if (flush != Z_BLOCK) { /* FULL_FLUSH or SYNC_FLUSH */

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

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

   870                  * as a special marker by inflate_sync().

   871                  */

   872                 if (flush == Z_FULL_FLUSH) {

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

   874                     if (s->lookahead == 0) {

   875                         s->strstart = 0;

   876                         s->block_start = 0L;

   877                     }

   878                 }

   879             }

   880             flush_pending(strm);

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

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

   883               return Z_OK;

   884             }

   885         }

   886     }

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

   888 

   889     if (flush != Z_FINISH) return Z_OK;

   890     if (s->wrap <= 0) return Z_STREAM_END;

   891 

   892     /* Write the trailer */

   893 #ifdef GZIP

   894     if (s->wrap == 2) {

   895         put_byte(s, (Byte)(strm->adler & 0xff));

   896         put_byte(s, (Byte)((strm->adler >> 8) & 0xff));

   897         put_byte(s, (Byte)((strm->adler >> 16) & 0xff));

   898         put_byte(s, (Byte)((strm->adler >> 24) & 0xff));

   899         put_byte(s, (Byte)(strm->total_in & 0xff));

   900         put_byte(s, (Byte)((strm->total_in >> 8) & 0xff));

   901         put_byte(s, (Byte)((strm->total_in >> 16) & 0xff));

   902         put_byte(s, (Byte)((strm->total_in >> 24) & 0xff));

   903     }

   904     else

   905 #endif

   906     {

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

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

   909     }

   910     flush_pending(strm);

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

   912      * to flush the rest.

   913      */

   914     if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */

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

   916 }

   917 

   918 /* ========================================================================= */

   919 int ZEXPORT deflateEnd (strm)

   920     z_streamp strm;

   921 {

   922     int status;

   923 

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

   925 

   926     status = strm->state->status;

   927     if (status != INIT_STATE &&

   928         status != EXTRA_STATE &&

   929         status != NAME_STATE &&

   930         status != COMMENT_STATE &&

   931         status != HCRC_STATE &&

   932         status != BUSY_STATE &&

   933         status != FINISH_STATE) {

   934       return Z_STREAM_ERROR;

   935     }

   936 

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

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

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

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

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

   942 

   943     ZFREE(strm, strm->state);

   944     strm->state = Z_NULL;

   945 

   946     return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK;

   947 }

   948 

   949 /* =========================================================================

   950  * Copy the source state to the destination state.

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

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

   953  */

   954 int ZEXPORT deflateCopy (dest, source)

   955     z_streamp dest;

   956     z_streamp source;

   957 {

   958 #ifdef MAXSEG_64K

   959     return Z_STREAM_ERROR;

   960 #else

   961     deflate_state *ds;

   962     deflate_state *ss;

   963     ushf *overlay;

   964 

   965 

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

   967         return Z_STREAM_ERROR;

   968     }

   969 

   970     ss = source->state;

   971 

   972     zmemcpy(dest, source, sizeof(z_stream));

   973 

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

   975     if (ds == Z_NULL) return Z_MEM_ERROR;

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

   977     zmemcpy(ds, ss, sizeof(deflate_state));

   978     ds->strm = dest;

   979 

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

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

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

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

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

   985 

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

   987         ds->pending_buf == Z_NULL) {

   988         deflateEnd (dest);

   989         return Z_MEM_ERROR;

   990     }

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

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

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

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

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

   996 

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

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

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

  1000 

  1001     ds->l_desc.dyn_tree = ds->dyn_ltree;

  1002     ds->d_desc.dyn_tree = ds->dyn_dtree;

  1003     ds->bl_desc.dyn_tree = ds->bl_tree;

  1004 

  1005     return Z_OK;

  1006 #endif /* MAXSEG_64K */

  1007 }

  1008 

  1009 /* ===========================================================================

  1010  * Read a new buffer from the current input stream, update the adler32

  1011  * and total number of bytes read.  All deflate() input goes through

  1012  * this function so some applications may wish to modify it to avoid

  1013  * allocating a large strm->next_in buffer and copying from it.

  1014  * (See also flush_pending()).

  1015  */

  1016 local int read_buf(strm, buf, size)

  1017     z_streamp strm;

  1018     Bytef *buf;

  1019     unsigned size;

  1020 {

  1021     unsigned len = strm->avail_in;

  1022 

  1023     if (len > size) len = size;

  1024     if (len == 0) return 0;

  1025 

  1026     strm->avail_in  -= len;

  1027 

  1028     if (strm->state->wrap == 1) {

  1029         strm->adler = adler32(strm->adler, strm->next_in, len);

  1030     }

  1031 #ifdef GZIP

  1032     else if (strm->state->wrap == 2) {

  1033         strm->adler = crc32(strm->adler, strm->next_in, len);

  1034     }

  1035 #endif

  1036     zmemcpy(buf, strm->next_in, len);

  1037     strm->next_in  += len;

  1038     strm->total_in += len;

  1039 

  1040     return (int)len;

  1041 }

  1042 

  1043 /* ===========================================================================

  1044  * Initialize the "longest match" routines for a new zlib stream

  1045  */

  1046 local void lm_init (s)

  1047     deflate_state *s;

  1048 {

  1049     s->window_size = (ulg)2L*s->w_size;

  1050 

  1051     CLEAR_HASH(s);

  1052 

  1053     /* Set the default configuration parameters:

  1054      */

  1055     s->max_lazy_match   = configuration_table[s->level].max_lazy;

  1056     s->good_match       = configuration_table[s->level].good_length;

  1057     s->nice_match       = configuration_table[s->level].nice_length;

  1058     s->max_chain_length = configuration_table[s->level].max_chain;

  1059 

  1060     s->strstart = 0;

  1061     s->block_start = 0L;

  1062     s->lookahead = 0;

  1063     s->match_length = s->prev_length = MIN_MATCH-1;

  1064     s->match_available = 0;

  1065     s->ins_h = 0;

  1066 #ifndef FASTEST

  1067 #ifdef ASMV

  1068     match_init(); /* initialize the asm code */

  1069 #endif

  1070 #endif

  1071 }

  1072 

  1073 #ifndef FASTEST

  1074 /* ===========================================================================

  1075  * Set match_start to the longest match starting at the given string and

  1076  * return its length. Matches shorter or equal to prev_length are discarded,

  1077  * in which case the result is equal to prev_length and match_start is

  1078  * garbage.

  1079  * IN assertions: cur_match is the head of the hash chain for the current

  1080  *   string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1

  1081  * OUT assertion: the match length is not greater than s->lookahead.

  1082  */

  1083 #ifndef ASMV

  1084 /* For 80x86 and 680x0, an optimized version will be provided in match.asm or

  1085  * match.S. The code will be functionally equivalent.

  1086  */

  1087 local uInt longest_match(s, cur_match)

  1088     deflate_state *s;

  1089     IPos cur_match;                             /* current match */

  1090 {

  1091     unsigned chain_length = s->max_chain_length;/* max hash chain length */

  1092     register Bytef *scan = s->window + s->strstart; /* current string */

  1093     register Bytef *match;                       /* matched string */

  1094     register int len;                           /* length of current match */

  1095     int best_len = s->prev_length;              /* best match length so far */

  1096     int nice_match = s->nice_match;             /* stop if match long enough */

  1097     IPos limit = s->strstart > (IPos)MAX_DIST(s) ?

  1098         s->strstart - (IPos)MAX_DIST(s) : NIL;

  1099     /* Stop when cur_match becomes <= limit. To simplify the code,

  1100      * we prevent matches with the string of window index 0.

  1101      */

  1102     Posf *prev = s->prev;

  1103     uInt wmask = s->w_mask;

  1104 

  1105 #ifdef UNALIGNED_OK

  1106     /* Compare two bytes at a time. Note: this is not always beneficial.

  1107      * Try with and without -DUNALIGNED_OK to check.

  1108      */

  1109     register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1;

  1110     register ush scan_start = *(ushf*)scan;

  1111     register ush scan_end   = *(ushf*)(scan+best_len-1);

  1112 #else

  1113     register Bytef *strend = s->window + s->strstart + MAX_MATCH;

  1114     register Byte scan_end1  = scan[best_len-1];

  1115     register Byte scan_end   = scan[best_len];

  1116 #endif

  1117 

  1118     /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.

  1119      * It is easy to get rid of this optimization if necessary.

  1120      */

  1121     Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");

  1122 

  1123     /* Do not waste too much time if we already have a good match: */

  1124     if (s->prev_length >= s->good_match) {

  1125         chain_length >>= 2;

  1126     }

  1127     /* Do not look for matches beyond the end of the input. This is necessary

  1128      * to make deflate deterministic.

  1129      */

  1130     if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead;

  1131 

  1132     Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");

  1133 

  1134     do {

  1135         Assert(cur_match < s->strstart, "no future");