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) 1995-2013 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://tools.ietf.org/html/rfc1951

    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 1.2.8 Copyright 1995-2013 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 /* rank Z_BLOCK between Z_NO_FLUSH and Z_PARTIAL_FLUSH */

   183 #define RANK(f) (((f) << 1) - ((f) > 4 ? 9 : 0))

   184 

   185 /* ===========================================================================

   186  * Update a hash value with the given input byte

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

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

   189  *    previous key instead of complete recalculation each time.

   190  */

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

   192 

   193 

   194 /* ===========================================================================

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

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

   197  * the previous length of the hash chain.

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

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

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

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

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

   203  */

   204 #ifdef FASTEST

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

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

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

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

   209 #else

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

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

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

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

   214 #endif

   215 

   216 /* ===========================================================================

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

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

   219  */

   220 #define CLEAR_HASH(s) \

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

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

   223 

   224 /* ========================================================================= */

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

   226     z_streamp strm;

   227     int level;

   228     const char *version;

   229     int stream_size;

   230 {

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

   232                          Z_DEFAULT_STRATEGY, version, stream_size);

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

   234 }

   235 

   236 /* ========================================================================= */

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

   238                   version, stream_size)

   239     z_streamp strm;

   240     int  level;

   241     int  method;

   242     int  windowBits;

   243     int  memLevel;

   244     int  strategy;

   245     const char *version;

   246     int stream_size;

   247 {

   248     deflate_state *s;

   249     int wrap = 1;

   250     static const char my_version[] = ZLIB_VERSION;

   251 

   252     ushf *overlay;

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

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

   255      */

   256 

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

   258         stream_size != sizeof(z_stream)) {

   259         return Z_VERSION_ERROR;

   260     }

   261     if (strm == Z_NULL) return Z_STREAM_ERROR;

   262 

   263     strm->msg = Z_NULL;

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

   265 #ifdef Z_SOLO

   266         return Z_STREAM_ERROR;

   267 #else

   268         strm->zalloc = zcalloc;

   269         strm->opaque = (voidpf)0;

   270 #endif

   271     }

   272     if (strm->zfree == (free_func)0)

   273 #ifdef Z_SOLO

   274         return Z_STREAM_ERROR;

   275 #else

   276         strm->zfree = zcfree;

   277 #endif

   278 

   279 #ifdef FASTEST

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

   281 #else

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

   283 #endif

   284 

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

   286         wrap = 0;

   287         windowBits = -windowBits;

   288     }

   289 #ifdef GZIP

   290     else if (windowBits > 15) {

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

   292         windowBits -= 16;

   293     }

   294 #endif

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

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

   297         strategy < 0 || strategy > Z_FIXED) {

   298         return Z_STREAM_ERROR;

   299     }

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

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

   302     if (s == Z_NULL) return Z_MEM_ERROR;

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

   304     s->strm = strm;

   305 

   306     s->wrap = wrap;

   307     s->gzhead = Z_NULL;

   308     s->w_bits = windowBits;

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

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

   311 

   312     s->hash_bits = memLevel + 7;

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

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

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

   316 

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

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

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

   320 

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

   322 

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

   324 

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

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

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

   328 

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

   330         s->pending_buf == Z_NULL) {

   331         s->status = FINISH_STATE;

   332         strm->msg = ERR_MSG(Z_MEM_ERROR);

   333         deflateEnd (strm);

   334         return Z_MEM_ERROR;

   335     }

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

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

   338 

   339     s->level = level;

   340     s->strategy = strategy;

   341     s->method = (Byte)method;

   342 

   343     return deflateReset(strm);

   344 }

   345 

   346 /* ========================================================================= */

   347 int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength)

   348     z_streamp strm;

   349     const Bytef *dictionary;

   350     uInt  dictLength;

   351 {

   352     deflate_state *s;

   353     uInt str, n;

   354     int wrap;

   355     unsigned avail;

   356     z_const unsigned char *next;

   357 

   358     if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL)

   359         return Z_STREAM_ERROR;

   360     s = strm->state;

   361     wrap = s->wrap;

   362     if (wrap == 2 || (wrap == 1 && s->status != INIT_STATE) || s->lookahead)

   363         return Z_STREAM_ERROR;

   364 

   365     /* when using zlib wrappers, compute Adler-32 for provided dictionary */

   366     if (wrap == 1)

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

   368     s->wrap = 0;                    /* avoid computing Adler-32 in read_buf */

   369 

   370     /* if dictionary would fill window, just replace the history */

   371     if (dictLength >= s->w_size) {

   372         if (wrap == 0) {            /* already empty otherwise */

   373             CLEAR_HASH(s);

   374             s->strstart = 0;

   375             s->block_start = 0L;

   376             s->insert = 0;

   377         }

   378         dictionary += dictLength - s->w_size;  /* use the tail */

   379         dictLength = s->w_size;

   380     }

   381 

   382     /* insert dictionary into window and hash */

   383     avail = strm->avail_in;

   384     next = strm->next_in;

   385     strm->avail_in = dictLength;

   386     strm->next_in = (z_const Bytef *)dictionary;

   387     fill_window(s);

   388     while (s->lookahead >= MIN_MATCH) {

   389         str = s->strstart;

   390         n = s->lookahead - (MIN_MATCH-1);

   391         do {

   392             UPDATE_HASH(s, s->ins_h, s->window[str + MIN_MATCH-1]);

   393 #ifndef FASTEST

   394             s->prev[str & s->w_mask] = s->head[s->ins_h];

   395 #endif

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

   397             str++;

   398         } while (--n);

   399         s->strstart = str;

   400         s->lookahead = MIN_MATCH-1;

   401         fill_window(s);

   402     }

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

   404     s->block_start = (long)s->strstart;

   405     s->insert = s->lookahead;

   406     s->lookahead = 0;

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

   408     s->match_available = 0;

   409     strm->next_in = next;

   410     strm->avail_in = avail;

   411     s->wrap = wrap;

   412     return Z_OK;

   413 }

   414 

   415 /* ========================================================================= */

   416 int ZEXPORT deflateResetKeep (strm)

   417     z_streamp strm;

   418 {

   419     deflate_state *s;

   420 

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

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

   423         return Z_STREAM_ERROR;

   424     }

   425 

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

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

   428     strm->data_type = Z_UNKNOWN;

   429 

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

   431     s->pending = 0;

   432     s->pending_out = s->pending_buf;

   433 

   434     if (s->wrap < 0) {

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

   436     }

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

   438     strm->adler =

   439 #ifdef GZIP

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

   441 #endif

   442         adler32(0L, Z_NULL, 0);

   443     s->last_flush = Z_NO_FLUSH;

   444 

   445     _tr_init(s);

   446 

   447     return Z_OK;

   448 }

   449 

   450 /* ========================================================================= */

   451 int ZEXPORT deflateReset (strm)

   452     z_streamp strm;

   453 {

   454     int ret;

   455 

   456     ret = deflateResetKeep(strm);

   457     if (ret == Z_OK)

   458         lm_init(strm->state);

   459     return ret;

   460 }

   461 

   462 /* ========================================================================= */

   463 int ZEXPORT deflateSetHeader (strm, head)

   464     z_streamp strm;

   465     gz_headerp head;

   466 {

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

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

   469     strm->state->gzhead = head;

   470     return Z_OK;

   471 }

   472 

   473 /* ========================================================================= */

   474 int ZEXPORT deflatePending (strm, pending, bits)

   475     unsigned *pending;

   476     int *bits;

   477     z_streamp strm;

   478 {

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

   480     if (pending != Z_NULL)

   481         *pending = strm->state->pending;

   482     if (bits != Z_NULL)

   483         *bits = strm->state->bi_valid;

   484     return Z_OK;

   485 }

   486 

   487 /* ========================================================================= */

   488 int ZEXPORT deflatePrime (strm, bits, value)

   489     z_streamp strm;

   490     int bits;

   491     int value;

   492 {

   493     deflate_state *s;

   494     int put;

   495 

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

   497     s = strm->state;

   498     if ((Bytef *)(s->d_buf) < s->pending_out + ((Buf_size + 7) >> 3))

   499         return Z_BUF_ERROR;

   500     do {

   501         put = Buf_size - s->bi_valid;

   502         if (put > bits)

   503             put = bits;

   504         s->bi_buf |= (ush)((value & ((1 << put) - 1)) << s->bi_valid);

   505         s->bi_valid += put;

   506         _tr_flush_bits(s);

   507         value >>= put;

   508         bits -= put;

   509     } while (bits);

   510     return Z_OK;

   511 }

   512 

   513 /* ========================================================================= */

   514 int ZEXPORT deflateParams(strm, level, strategy)

   515     z_streamp strm;

   516     int level;

   517     int strategy;

   518 {

   519     deflate_state *s;

   520     compress_func func;

   521     int err = Z_OK;

   522 

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

   524     s = strm->state;

   525 

   526 #ifdef FASTEST

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

   528 #else

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

   530 #endif

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

   532         return Z_STREAM_ERROR;

   533     }

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

   535 

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

   537         strm->total_in != 0) {

   538         /* Flush the last buffer: */

   539         err = deflate(strm, Z_BLOCK);

   540         if (err == Z_BUF_ERROR && s->pending == 0)

   541             err = Z_OK;

   542     }

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

   544         s->level = level;

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

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

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

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

   549     }

   550     s->strategy = strategy;

   551     return err;

   552 }

   553 

   554 /* ========================================================================= */

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

   556     z_streamp strm;

   557     int good_length;

   558     int max_lazy;

   559     int nice_length;

   560     int max_chain;

   561 {

   562     deflate_state *s;

   563 

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

   565     s = strm->state;

   566     s->good_match = good_length;

   567     s->max_lazy_match = max_lazy;

   568     s->nice_match = nice_length;

   569     s->max_chain_length = max_chain;

   570     return Z_OK;

   571 }

   572 

   573 /* =========================================================================

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

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

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

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

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

   579  *

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

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

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

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

   584  *

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

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

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

   588  * allocation.

   589  */

   590 uLong ZEXPORT deflateBound(strm, sourceLen)

   591     z_streamp strm;

   592     uLong sourceLen;

   593 {

   594     deflate_state *s;

   595     uLong complen, wraplen;

   596     Bytef *str;

   597 

   598     /* conservative upper bound for compressed data */

   599     complen = sourceLen +

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

   601 

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

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

   604         return complen + 6;

   605 

   606     /* compute wrapper length */

   607     s = strm->state;

   608     switch (s->wrap) {

   609     case 0:                                 /* raw deflate */

   610         wraplen = 0;

   611         break;

   612     case 1:                                 /* zlib wrapper */

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

   614         break;

   615     case 2:                                 /* gzip wrapper */

   616         wraplen = 18;

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

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

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

   620             str = s->gzhead->name;

   621             if (str != Z_NULL)

   622                 do {

   623                     wraplen++;

   624                 } while (*str++);

   625             str = s->gzhead->comment;

   626             if (str != Z_NULL)

   627                 do {

   628                     wraplen++;

   629                 } while (*str++);

   630             if (s->gzhead->hcrc)

   631                 wraplen += 2;

   632         }

   633         break;

   634     default:                                /* for compiler happiness */

   635         wraplen = 6;

   636     }

   637 

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

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

   640         return complen + wraplen;

   641 

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

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

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

   645 }

   646 

   647 /* =========================================================================

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

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

   650  * pending_buf.

   651  */

   652 local void putShortMSB (s, b)

   653     deflate_state *s;

   654     uInt b;

   655 {

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

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

   658 }

   659 

   660 /* =========================================================================

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

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

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

   664  * (See also read_buf()).

   665  */

   666 local void flush_pending(strm)

   667     z_streamp strm;

   668 {

   669     unsigned len;

   670     deflate_state *s = strm->state;

   671 

   672     _tr_flush_bits(s);

   673     len = s->pending;

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

   675     if (len == 0) return;

   676 

   677     zmemcpy(strm->next_out, s->pending_out, len);

   678     strm->next_out  += len;

   679     s->pending_out  += len;

   680     strm->total_out += len;

   681     strm->avail_out  -= len;

   682     s->pending -= len;

   683     if (s->pending == 0) {

   684         s->pending_out = s->pending_buf;

   685     }

   686 }

   687 

   688 /* ========================================================================= */

   689 int ZEXPORT deflate (strm, flush)

   690     z_streamp strm;

   691     int flush;

   692 {

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

   694     deflate_state *s;

   695 

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

   697         flush > Z_BLOCK || flush < 0) {

   698         return Z_STREAM_ERROR;

   699     }

   700     s = strm->state;

   701 

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

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

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

   705         ERR_RETURN(strm, Z_STREAM_ERROR);

   706     }

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

   708 

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

   710     old_flush = s->last_flush;

   711     s->last_flush = flush;

   712 

   713     /* Write the header */

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

   715 #ifdef GZIP

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

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

   718             put_byte(s, 31);

   719             put_byte(s, 139);

   720             put_byte(s, 8);

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

   722                 put_byte(s, 0);

   723                 put_byte(s, 0);

   724                 put_byte(s, 0);

   725                 put_byte(s, 0);

   726                 put_byte(s, 0);

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

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

   729                              4 : 0));

   730                 put_byte(s, OS_CODE);

   731                 s->status = BUSY_STATE;

   732             }

   733             else {

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

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

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

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

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

   739                         );

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

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

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

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

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

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

   746                              4 : 0));

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

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

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

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

   751                 }

   752                 if (s->gzhead->hcrc)

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

   754                                         s->pending);

   755                 s->gzindex = 0;

   756                 s->status = EXTRA_STATE;

   757             }

   758         }

   759         else

   760 #endif

   761         {

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

   763             uInt level_flags;

   764 

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

   766                 level_flags = 0;

   767             else if (s->level < 6)

   768                 level_flags = 1;

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

   770                 level_flags = 2;

   771             else

   772                 level_flags = 3;

   773             header |= (level_flags << 6);

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

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

   776 

   777             s->status = BUSY_STATE;

   778             putShortMSB(s, header);

   779 

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

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

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

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

   784             }

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

   786         }

   787     }

   788 #ifdef GZIP

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

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

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

   792 

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

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

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

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

   797                                             s->pending - beg);

   798                     flush_pending(strm);

   799                     beg = s->pending;

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

   801                         break;

   802                 }

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

   804                 s->gzindex++;

   805             }

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

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

   808                                     s->pending - beg);

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

   810                 s->gzindex = 0;

   811                 s->status = NAME_STATE;

   812             }

   813         }

   814         else

   815             s->status = NAME_STATE;

   816     }

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

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

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

   820             int val;

   821 

   822             do {

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

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

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

   826                                             s->pending - beg);

   827                     flush_pending(strm);

   828                     beg = s->pending;

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

   830                         val = 1;

   831                         break;

   832                     }

   833                 }

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

   835                 put_byte(s, val);

   836             } while (val != 0);

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

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

   839                                     s->pending - beg);

   840             if (val == 0) {

   841                 s->gzindex = 0;

   842                 s->status = COMMENT_STATE;

   843             }

   844         }

   845         else

   846             s->status = COMMENT_STATE;

   847     }

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

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

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

   851             int val;

   852 

   853             do {

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

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

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

   857                                             s->pending - beg);

   858                     flush_pending(strm);

   859                     beg = s->pending;

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

   861                         val = 1;

   862                         break;

   863                     }

   864                 }

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

   866                 put_byte(s, val);

   867             } while (val != 0);

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

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

   870                                     s->pending - beg);

   871             if (val == 0)

   872                 s->status = HCRC_STATE;

   873         }

   874         else

   875             s->status = HCRC_STATE;

   876     }

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

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

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

   880                 flush_pending(strm);

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

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

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

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

   885                 s->status = BUSY_STATE;

   886             }

   887         }

   888         else

   889             s->status = BUSY_STATE;

   890     }

   891 #endif

   892 

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

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

   895         flush_pending(strm);

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

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

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

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

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

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

   902              */

   903             s->last_flush = -1;

   904             return Z_OK;

   905         }

   906 

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

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

   909      * returning Z_STREAM_END instead of Z_BUF_ERROR.

   910      */

   911     } else if (strm->avail_in == 0 && RANK(flush) <= RANK(old_flush) &&

   912                flush != Z_FINISH) {

   913         ERR_RETURN(strm, Z_BUF_ERROR);

   914     }

   915 

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

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

   918         ERR_RETURN(strm, Z_BUF_ERROR);

   919     }

   920 

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

   922      */

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

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

   925         block_state bstate;

   926 

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

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

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

   930 

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

   932             s->status = FINISH_STATE;

   933         }

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

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

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

   937             }

   938             return Z_OK;

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

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

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

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

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

   944              * one empty block.

   945              */

   946         }

   947         if (bstate == block_done) {

   948             if (flush == Z_PARTIAL_FLUSH) {

   949                 _tr_align(s);

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

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

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

   953                  * as a special marker by inflate_sync().

   954                  */

   955                 if (flush == Z_FULL_FLUSH) {

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

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

   958                         s->strstart = 0;

   959                         s->block_start = 0L;

   960                         s->insert = 0;

   961                     }

   962                 }

   963             }

   964             flush_pending(strm);

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

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

   967               return Z_OK;

   968             }

   969         }

   970     }

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

   972 

   973     if (flush != Z_FINISH) return Z_OK;

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

   975 

   976     /* Write the trailer */

   977 #ifdef GZIP

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

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

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

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

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

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

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

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

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

   987     }

   988     else

   989 #endif

   990     {

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

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

   993     }

   994     flush_pending(strm);

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

   996      * to flush the rest.

   997      */

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

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

  1000 }

  1001 

  1002 /* ========================================================================= */

  1003 int ZEXPORT deflateEnd (strm)

  1004     z_streamp strm;

  1005 {

  1006     int status;

  1007 

  1008     if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;

  1009 

  1010     status = strm->state->status;

  1011     if (status != INIT_STATE &&

  1012         status != EXTRA_STATE &&

  1013         status != NAME_STATE &&

  1014         status != COMMENT_STATE &&

  1015         status != HCRC_STATE &&

  1016         status != BUSY_STATE &&

  1017         status != FINISH_STATE) {

  1018       return Z_STREAM_ERROR;

  1019     }

  1020 

  1021     /* Deallocate in reverse order of allocations: */

  1022     TRY_FREE(strm, strm->state->pending_buf);

  1023     TRY_FREE(strm, strm->state->head);

  1024     TRY_FREE(strm, strm->state->prev);

  1025     TRY_FREE(strm, strm->state->window);

  1026 

  1027     ZFREE(strm, strm->state);

  1028     strm->state = Z_NULL;

  1029 

  1030     return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK;

  1031 }

  1032 

  1033 /* =========================================================================

  1034  * Copy the source state to the destination state.

  1035  * To simplify the source, this is not supported for 16-bit MSDOS (which

  1036  * doesn't have enough memory anyway to duplicate compression states).

  1037  */

  1038 int ZEXPORT deflateCopy (dest, source)

  1039     z_streamp dest;

  1040     z_streamp source;

  1041 {

  1042 #ifdef MAXSEG_64K

  1043     return Z_STREAM_ERROR;

  1044 #else

  1045     deflate_state *ds;

  1046     deflate_state *ss;

  1047     ushf *overlay;

  1048 

  1049 

  1050     if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL) {

  1051         return Z_STREAM_ERROR;

  1052     }

  1053 

  1054     ss = source->state;

  1055 

  1056     zmemcpy((voidpf)dest, (voidpf)source, sizeof(z_stream));

  1057 

  1058     ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state));

  1059     if (ds == Z_NULL) return Z_MEM_ERROR;

  1060     dest->state = (struct internal_state FAR *) ds;

  1061     zmemcpy((voidpf)ds, (voidpf)ss, sizeof(deflate_state));

  1062     ds->strm = dest;

  1063 

  1064     ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte));

  1065     ds->prev   = (Posf *)  ZALLOC(dest, ds->w_size, sizeof(Pos));

  1066     ds->head   = (Posf *)  ZALLOC(dest, ds->hash_size, sizeof(Pos));

  1067     overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2);

  1068     ds->pending_buf = (uchf *) overlay;

  1069 

  1070     if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL ||

  1071         ds->pending_buf == Z_NULL) {

  1072         deflateEnd (dest);

  1073         return Z_MEM_ERROR;

  1074     }

  1075     /* following zmemcpy do not work for 16-bit MSDOS */

  1076     zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte));

  1077     zmemcpy((voidpf)ds->prev, (voidpf)ss->prev, ds->w_size * sizeof(Pos));

  1078     zmemcpy((voidpf)ds->head, (voidpf)ss->head, ds->hash_size * sizeof(Pos));

  1079     zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size);

  1080 

  1081     ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf);

  1082     ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush);

  1083     ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize;

  1084 

  1085     ds->l_desc.dyn_tree = ds->dyn_ltree;

  1086     ds->d_desc.dyn_tree = ds->dyn_dtree;

  1087     ds->bl_desc.dyn_tree = ds->bl_tree;

  1088 

  1089     return Z_OK;

  1090 #endif /* MAXSEG_64K */

  1091 }

  1092 

  1093 /* ===========================================================================

  1094  * Read a new buffer from the current input stream, update the adler32

  1095  * and total number of bytes read.  All deflate() input goes through

  1096  * this function so some applications may wish to modify it to avoid

  1097  * allocating a large strm->next_in buffer and copying from it.

  1098  * (See also flush_pending()).

  1099  */

  1100 local int read_buf(strm, buf, size)

  1101     z_streamp strm;

  1102     Bytef *buf;

  1103     unsigned size;

  1104 {

  1105     unsigned len = strm->avail_in;

  1106 

  1107     if (len > size) len = size;

  1108     if (len == 0) return 0;

  1109 

  1110     strm->avail_in  -= len;

  1111 

  1112     zmemcpy(buf, strm->next_in, len);

  1113     if (strm->state->wrap == 1) {

  1114         strm->adler = adler32(strm->adler, buf, len);

  1115     }

  1116 #ifdef GZIP

  1117     else if (strm->state->wrap == 2) {

  1118         strm->adler = crc32(strm->adler, buf, len);

  1119     }

  1120 #endif

  1121     strm->next_in  += len;

  1122     strm->total_in += len;

  1123 

  1124     return (int)len;

  1125 }

  1126 

  1127 /* ===========================================================================

  1128  * Initialize the "longest match" routines for a new zlib stream

  1129  */

  1130 local void lm_init (s)

  1131     deflate_state *s;

  1132 {

  1133     s->window_size = (ulg)2L*s->w_size;

  1134