1 /* trees.c -- output deflated data using Huffman coding

     2  * Copyright (C) 1995-2005 Jean-loup Gailly

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

     4  */

     5 

     6 /*

     7  *  ALGORITHM

     8  *

     9  *      The "deflation" process uses several Huffman trees. The more

    10  *      common source values are represented by shorter bit sequences.

    11  *

    12  *      Each code tree is stored in a compressed form which is itself

    13  * a Huffman encoding of the lengths of all the code strings (in

    14  * ascending order by source values).  The actual code strings are

    15  * reconstructed from the lengths in the inflate process, as described

    16  * in the deflate specification.

    17  *

    18  *  REFERENCES

    19  *

    20  *      Deutsch, L.P.,"'Deflate' Compressed Data Format Specification".

    21  *      Available in ftp.uu.net:/pub/archiving/zip/doc/deflate-1.1.doc

    22  *

    23  *      Storer, James A.

    24  *          Data Compression:  Methods and Theory, pp. 49-50.

    25  *          Computer Science Press, 1988.  ISBN 0-7167-8156-5.

    26  *

    27  *      Sedgewick, R.

    28  *          Algorithms, p290.

    29  *          Addison-Wesley, 1983. ISBN 0-201-06672-6.

    30  */

    31 

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

    33 

    34 /* #define GEN_TREES_H */

    35 

    36 #include "deflate.h"

    37 

    38 #ifdef DEBUG

    39 #  include <ctype.h>

    40 #endif

    41 

    42 /* ===========================================================================

    43  * Constants

    44  */

    45 

    46 #define MAX_BL_BITS 7

    47 /* Bit length codes must not exceed MAX_BL_BITS bits */

    48 

    49 #define END_BLOCK 256

    50 /* end of block literal code */

    51 

    52 #define REP_3_6      16

    53 /* repeat previous bit length 3-6 times (2 bits of repeat count) */

    54 

    55 #define REPZ_3_10    17

    56 /* repeat a zero length 3-10 times  (3 bits of repeat count) */

    57 

    58 #define REPZ_11_138  18

    59 /* repeat a zero length 11-138 times  (7 bits of repeat count) */

    60 

    61 local const int extra_lbits[LENGTH_CODES] /* extra bits for each length code */

    62    = {0,0,0,0,0,0,0,0,1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,4,5,5,5,5,0};

    63 

    64 local const int extra_dbits[D_CODES] /* extra bits for each distance code */

    65    = {0,0,0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13};

    66 

    67 local const int extra_blbits[BL_CODES]/* extra bits for each bit length code */

    68    = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7};

    69 

    70 local const uch bl_order[BL_CODES]

    71    = {16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15};

    72 /* The lengths of the bit length codes are sent in order of decreasing

    73  * probability, to avoid transmitting the lengths for unused bit length codes.

    74  */

    75 

    76 #define Buf_size (8 * 2*sizeof(char))

    77 /* Number of bits used within bi_buf. (bi_buf might be implemented on

    78  * more than 16 bits on some systems.)

    79  */

    80 

    81 /* ===========================================================================

    82  * Local data. These are initialized only once.

    83  */

    84 

    85 #define DIST_CODE_LEN  512 /* see definition of array dist_code below */

    86 

    87 #if defined(GEN_TREES_H) || !defined(STDC)

    88 /* non ANSI compilers may not accept trees.h */

    89 

    90 local ct_data static_ltree[L_CODES+2];

    91 /* The static literal tree. Since the bit lengths are imposed, there is no

    92  * need for the L_CODES extra codes used during heap construction. However

    93  * The codes 286 and 287 are needed to build a canonical tree (see _tr_init

    94  * below).

    95  */

    96 

    97 local ct_data static_dtree[D_CODES];

    98 /* The static distance tree. (Actually a trivial tree since all codes use

    99  * 5 bits.)

   100  */

   101 

   102 uch _dist_code[DIST_CODE_LEN];

   103 /* Distance codes. The first 256 values correspond to the distances

   104  * 3 .. 258, the last 256 values correspond to the top 8 bits of

   105  * the 15 bit distances.

   106  */

   107 

   108 uch _length_code[MAX_MATCH-MIN_MATCH+1];

   109 /* length code for each normalized match length (0 == MIN_MATCH) */

   110 

   111 local int base_length[LENGTH_CODES];

   112 /* First normalized length for each code (0 = MIN_MATCH) */

   113 

   114 local int base_dist[D_CODES];

   115 /* First normalized distance for each code (0 = distance of 1) */

   116 

   117 #else

   118 #  include "trees.h"

   119 #endif /* GEN_TREES_H */

   120 

   121 struct static_tree_desc_s {

   122     const ct_data *static_tree;  /* static tree or NULL */

   123     const intf *extra_bits;      /* extra bits for each code or NULL */

   124     int     extra_base;          /* base index for extra_bits */

   125     int     elems;               /* max number of elements in the tree */

   126     int     max_length;          /* max bit length for the codes */

   127 };

   128 

   129 local static_tree_desc  static_l_desc =

   130 {static_ltree, extra_lbits, LITERALS+1, L_CODES, MAX_BITS};

   131 

   132 local static_tree_desc  static_d_desc =

   133 {static_dtree, extra_dbits, 0,          D_CODES, MAX_BITS};

   134 

   135 local static_tree_desc  static_bl_desc =

   136 {(const ct_data *)0, extra_blbits, 0,   BL_CODES, MAX_BL_BITS};

   137 

   138 /* ===========================================================================

   139  * Local (static) routines in this file.

   140  */

   141 

   142 local void tr_static_init OF((void));

   143 local void init_block     OF((deflate_state *s));

   144 local void pqdownheap     OF((deflate_state *s, ct_data *tree, int k));

   145 local void gen_bitlen     OF((deflate_state *s, tree_desc *desc));

   146 local void gen_codes      OF((ct_data *tree, int max_code, ushf *bl_count));

   147 local void build_tree     OF((deflate_state *s, tree_desc *desc));

   148 local void scan_tree      OF((deflate_state *s, ct_data *tree, int max_code));

   149 local void send_tree      OF((deflate_state *s, ct_data *tree, int max_code));

   150 local int  build_bl_tree  OF((deflate_state *s));

   151 local void send_all_trees OF((deflate_state *s, int lcodes, int dcodes,

   152                               int blcodes));

   153 local void compress_block OF((deflate_state *s, ct_data *ltree,

   154                               ct_data *dtree));

   155 local void set_data_type  OF((deflate_state *s));

   156 local unsigned bi_reverse OF((unsigned value, int length));

   157 local void bi_windup      OF((deflate_state *s));

   158 local void bi_flush       OF((deflate_state *s));

   159 local void copy_block     OF((deflate_state *s, charf *buf, unsigned len,

   160                               int header));

   161 

   162 #ifdef GEN_TREES_H

   163 local void gen_trees_header OF((void));

   164 #endif

   165 

   166 #ifndef DEBUG

   167 #  define send_code(s, c, tree) send_bits(s, tree[c].Code, tree[c].Len)

   168    /* Send a code of the given tree. c and tree must not have side effects */

   169 

   170 #else /* DEBUG */

   171 #  define send_code(s, c, tree) \

   172      { if (z_verbose>2) fprintf(stderr,"\ncd %3d ",(c)); \

   173        send_bits(s, tree[c].Code, tree[c].Len); }

   174 #endif

   175 

   176 /* ===========================================================================

   177  * Output a short LSB first on the stream.

   178  * IN assertion: there is enough room in pendingBuf.

   179  */

   180 #define put_short(s, w) { \

   181     put_byte(s, (uch)((w) & 0xff)); \

   182     put_byte(s, (uch)((ush)(w) >> 8)); \

   183 }

   184 

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

   186  * Send a value on a given number of bits.

   187  * IN assertion: length <= 16 and value fits in length bits.

   188  */

   189 #ifdef DEBUG

   190 local void send_bits      OF((deflate_state *s, int value, int length));

   191 

   192 local void send_bits(s, value, length)

   193     deflate_state *s;

   194     int value;  /* value to send */

   195     int length; /* number of bits */

   196 {

   197     Tracevv((stderr," l %2d v %4x ", length, value));

   198     Assert(length > 0 && length <= 15, "invalid length");

   199     s->bits_sent += (ulg)length;

   200 

   201     /* If not enough room in bi_buf, use (valid) bits from bi_buf and

   202      * (16 - bi_valid) bits from value, leaving (width - (16-bi_valid))

   203      * unused bits in value.

   204      */

   205     if (s->bi_valid > (int)Buf_size - length) {

   206         s->bi_buf |= (value << s->bi_valid);

   207         put_short(s, s->bi_buf);

   208         s->bi_buf = (ush)value >> (Buf_size - s->bi_valid);

   209         s->bi_valid += length - Buf_size;

   210     } else {

   211         s->bi_buf |= value << s->bi_valid;

   212         s->bi_valid += length;

   213     }

   214 }

   215 #else /* !DEBUG */

   216 

   217 #define send_bits(s, value, length) \

   218 { int len = length;\

   219   if (s->bi_valid > (int)Buf_size - len) {\

   220     int val = value;\

   221     s->bi_buf |= (val << s->bi_valid);\

   222     put_short(s, s->bi_buf);\

   223     s->bi_buf = (ush)val >> (Buf_size - s->bi_valid);\

   224     s->bi_valid += len - Buf_size;\

   225   } else {\

   226     s->bi_buf |= (value) << s->bi_valid;\

   227     s->bi_valid += len;\

   228   }\

   229 }

   230 #endif /* DEBUG */

   231 

   232 

   233 /* the arguments must not have side effects */

   234 

   235 /* ===========================================================================

   236  * Initialize the various 'constant' tables.

   237  */

   238 local void tr_static_init()

   239 {

   240 #if defined(GEN_TREES_H) || !defined(STDC)

   241     static int static_init_done = 0;

   242     int n;        /* iterates over tree elements */

   243     int bits;     /* bit counter */

   244     int length;   /* length value */

   245     int code;     /* code value */

   246     int dist;     /* distance index */

   247     ush bl_count[MAX_BITS+1];

   248     /* number of codes at each bit length for an optimal tree */

   249 

   250     if (static_init_done) return;

   251 

   252     /* For some embedded targets, global variables are not initialized: */

   253     static_l_desc.static_tree = static_ltree;

   254     static_l_desc.extra_bits = extra_lbits;

   255     static_d_desc.static_tree = static_dtree;

   256     static_d_desc.extra_bits = extra_dbits;

   257     static_bl_desc.extra_bits = extra_blbits;

   258 

   259     /* Initialize the mapping length (0..255) -> length code (0..28) */

   260     length = 0;

   261     for (code = 0; code < LENGTH_CODES-1; code++) {

   262         base_length[code] = length;

   263         for (n = 0; n < (1<<extra_lbits[code]); n++) {

   264             _length_code[length++] = (uch)code;

   265         }

   266     }

   267     Assert (length == 256, "tr_static_init: length != 256");

   268     /* Note that the length 255 (match length 258) can be represented

   269      * in two different ways: code 284 + 5 bits or code 285, so we

   270      * overwrite length_code[255] to use the best encoding:

   271      */

   272     _length_code[length-1] = (uch)code;

   273 

   274     /* Initialize the mapping dist (0..32K) -> dist code (0..29) */

   275     dist = 0;

   276     for (code = 0 ; code < 16; code++) {

   277         base_dist[code] = dist;

   278         for (n = 0; n < (1<<extra_dbits[code]); n++) {

   279             _dist_code[dist++] = (uch)code;

   280         }

   281     }

   282     Assert (dist == 256, "tr_static_init: dist != 256");

   283     dist >>= 7; /* from now on, all distances are divided by 128 */

   284     for ( ; code < D_CODES; code++) {

   285         base_dist[code] = dist << 7;

   286         for (n = 0; n < (1<<(extra_dbits[code]-7)); n++) {

   287             _dist_code[256 + dist++] = (uch)code;

   288         }

   289     }

   290     Assert (dist == 256, "tr_static_init: 256+dist != 512");

   291 

   292     /* Construct the codes of the static literal tree */

   293     for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0;

   294     n = 0;

   295     while (n <= 143) static_ltree[n++].Len = 8, bl_count[8]++;

   296     while (n <= 255) static_ltree[n++].Len = 9, bl_count[9]++;

   297     while (n <= 279) static_ltree[n++].Len = 7, bl_count[7]++;

   298     while (n <= 287) static_ltree[n++].Len = 8, bl_count[8]++;

   299     /* Codes 286 and 287 do not exist, but we must include them in the

   300      * tree construction to get a canonical Huffman tree (longest code

   301      * all ones)

   302      */

   303     gen_codes((ct_data *)static_ltree, L_CODES+1, bl_count);

   304 

   305     /* The static distance tree is trivial: */

   306     for (n = 0; n < D_CODES; n++) {

   307         static_dtree[n].Len = 5;

   308         static_dtree[n].Code = bi_reverse((unsigned)n, 5);

   309     }

   310     static_init_done = 1;

   311 

   312 #  ifdef GEN_TREES_H

   313     gen_trees_header();

   314 #  endif

   315 #endif /* defined(GEN_TREES_H) || !defined(STDC) */

   316 }

   317 

   318 /* ===========================================================================

   319  * Genererate the file trees.h describing the static trees.

   320  */

   321 #ifdef GEN_TREES_H

   322 #  ifndef DEBUG

   323 #    include <stdio.h>

   324 #  endif

   325 

   326 #  define SEPARATOR(i, last, width) \

   327       ((i) == (last)? "\n};\n\n" :    \

   328        ((i) % (width) == (width)-1 ? ",\n" : ", "))

   329 

   330 void gen_trees_header()

   331 {

   332     FILE *header = fopen("trees.h", "w");

   333     int i;

   334 

   335     Assert (header != NULL, "Can't open trees.h");

   336     fprintf(header,

   337             "/* header created automatically with -DGEN_TREES_H */\n\n");

   338 

   339     fprintf(header, "local const ct_data static_ltree[L_CODES+2] = {\n");

   340     for (i = 0; i < L_CODES+2; i++) {

   341         fprintf(header, "{{%3u},{%3u}}%s", static_ltree[i].Code,

   342                 static_ltree[i].Len, SEPARATOR(i, L_CODES+1, 5));

   343     }

   344 

   345     fprintf(header, "local const ct_data static_dtree[D_CODES] = {\n");

   346     for (i = 0; i < D_CODES; i++) {

   347         fprintf(header, "{{%2u},{%2u}}%s", static_dtree[i].Code,

   348                 static_dtree[i].Len, SEPARATOR(i, D_CODES-1, 5));

   349     }

   350 

   351     fprintf(header, "const uch _dist_code[DIST_CODE_LEN] = {\n");

   352     for (i = 0; i < DIST_CODE_LEN; i++) {

   353         fprintf(header, "%2u%s", _dist_code[i],

   354                 SEPARATOR(i, DIST_CODE_LEN-1, 20));

   355     }

   356 

   357     fprintf(header, "const uch _length_code[MAX_MATCH-MIN_MATCH+1]= {\n");

   358     for (i = 0; i < MAX_MATCH-MIN_MATCH+1; i++) {

   359         fprintf(header, "%2u%s", _length_code[i],

   360                 SEPARATOR(i, MAX_MATCH-MIN_MATCH, 20));

   361     }

   362 

   363     fprintf(header, "local const int base_length[LENGTH_CODES] = {\n");

   364     for (i = 0; i < LENGTH_CODES; i++) {

   365         fprintf(header, "%1u%s", base_length[i],

   366                 SEPARATOR(i, LENGTH_CODES-1, 20));

   367     }

   368 

   369     fprintf(header, "local const int base_dist[D_CODES] = {\n");

   370     for (i = 0; i < D_CODES; i++) {

   371         fprintf(header, "%5u%s", base_dist[i],

   372                 SEPARATOR(i, D_CODES-1, 10));

   373     }

   374 

   375     fclose(header);

   376 }

   377 #endif /* GEN_TREES_H */

   378 

   379 /* ===========================================================================

   380  * Initialize the tree data structures for a new zlib stream.

   381  */

   382 void _tr_init(s)

   383     deflate_state *s;

   384 {

   385     tr_static_init();

   386 

   387     s->l_desc.dyn_tree = s->dyn_ltree;

   388     s->l_desc.stat_desc = &static_l_desc;

   389 

   390     s->d_desc.dyn_tree = s->dyn_dtree;

   391     s->d_desc.stat_desc = &static_d_desc;

   392 

   393     s->bl_desc.dyn_tree = s->bl_tree;

   394     s->bl_desc.stat_desc = &static_bl_desc;

   395 

   396     s->bi_buf = 0;

   397     s->bi_valid = 0;

   398     s->last_eob_len = 8; /* enough lookahead for inflate */

   399 #ifdef DEBUG

   400     s->compressed_len = 0L;

   401     s->bits_sent = 0L;

   402 #endif

   403 

   404     /* Initialize the first block of the first file: */

   405     init_block(s);

   406 }

   407 

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

   409  * Initialize a new block.

   410  */

   411 local void init_block(s)

   412     deflate_state *s;

   413 {

   414     int n; /* iterates over tree elements */

   415 

   416     /* Initialize the trees. */

   417     for (n = 0; n < L_CODES;  n++) s->dyn_ltree[n].Freq = 0;

   418     for (n = 0; n < D_CODES;  n++) s->dyn_dtree[n].Freq = 0;

   419     for (n = 0; n < BL_CODES; n++) s->bl_tree[n].Freq = 0;

   420 

   421     s->dyn_ltree[END_BLOCK].Freq = 1;

   422     s->opt_len = s->static_len = 0L;

   423     s->last_lit = s->matches = 0;

   424 }

   425 

   426 #define SMALLEST 1

   427 /* Index within the heap array of least frequent node in the Huffman tree */

   428 

   429 

   430 /* ===========================================================================

   431  * Remove the smallest element from the heap and recreate the heap with

   432  * one less element. Updates heap and heap_len.

   433  */

   434 #define pqremove(s, tree, top) \

   435 {\

   436     top = s->heap[SMALLEST]; \

   437     s->heap[SMALLEST] = s->heap[s->heap_len--]; \

   438     pqdownheap(s, tree, SMALLEST); \

   439 }

   440 

   441 /* ===========================================================================

   442  * Compares to subtrees, using the tree depth as tie breaker when

   443  * the subtrees have equal frequency. This minimizes the worst case length.

   444  */

   445 #define smaller(tree, n, m, depth) \

   446    (tree[n].Freq < tree[m].Freq || \

   447    (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m]))

   448 

   449 /* ===========================================================================

   450  * Restore the heap property by moving down the tree starting at node k,

   451  * exchanging a node with the smallest of its two sons if necessary, stopping

   452  * when the heap property is re-established (each father smaller than its

   453  * two sons).

   454  */

   455 local void pqdownheap(s, tree, k)

   456     deflate_state *s;

   457     ct_data *tree;  /* the tree to restore */

   458     int k;               /* node to move down */

   459 {

   460     int v = s->heap[k];

   461     int j = k << 1;  /* left son of k */

   462     while (j <= s->heap_len) {

   463         /* Set j to the smallest of the two sons: */

   464         if (j < s->heap_len &&

   465             smaller(tree, s->heap[j+1], s->heap[j], s->depth)) {

   466             j++;

   467         }

   468         /* Exit if v is smaller than both sons */

   469         if (smaller(tree, v, s->heap[j], s->depth)) break;

   470 

   471         /* Exchange v with the smallest son */

   472         s->heap[k] = s->heap[j];  k = j;

   473 

   474         /* And continue down the tree, setting j to the left son of k */

   475         j <<= 1;

   476     }

   477     s->heap[k] = v;

   478 }

   479 

   480 /* ===========================================================================

   481  * Compute the optimal bit lengths for a tree and update the total bit length

   482  * for the current block.

   483  * IN assertion: the fields freq and dad are set, heap[heap_max] and

   484  *    above are the tree nodes sorted by increasing frequency.

   485  * OUT assertions: the field len is set to the optimal bit length, the

   486  *     array bl_count contains the frequencies for each bit length.

   487  *     The length opt_len is updated; static_len is also updated if stree is

   488  *     not null.

   489  */

   490 local void gen_bitlen(s, desc)

   491     deflate_state *s;

   492     tree_desc *desc;    /* the tree descriptor */

   493 {

   494     ct_data *tree        = desc->dyn_tree;

   495     int max_code         = desc->max_code;

   496     const ct_data *stree = desc->stat_desc->static_tree;

   497     const intf *extra    = desc->stat_desc->extra_bits;

   498     int base             = desc->stat_desc->extra_base;

   499     int max_length       = desc->stat_desc->max_length;

   500     int h;              /* heap index */

   501     int n, m;           /* iterate over the tree elements */

   502     int bits;           /* bit length */

   503     int xbits;          /* extra bits */

   504     ush f;              /* frequency */

   505     int overflow = 0;   /* number of elements with bit length too large */

   506 

   507     for (bits = 0; bits <= MAX_BITS; bits++) s->bl_count[bits] = 0;

   508 

   509     /* In a first pass, compute the optimal bit lengths (which may

   510      * overflow in the case of the bit length tree).

   511      */

   512     tree[s->heap[s->heap_max]].Len = 0; /* root of the heap */

   513 

   514     for (h = s->heap_max+1; h < HEAP_SIZE; h++) {

   515         n = s->heap[h];

   516         bits = tree[tree[n].Dad].Len + 1;

   517         if (bits > max_length) bits = max_length, overflow++;

   518         tree[n].Len = (ush)bits;

   519         /* We overwrite tree[n].Dad which is no longer needed */

   520 

   521         if (n > max_code) continue; /* not a leaf node */

   522 

   523         s->bl_count[bits]++;

   524         xbits = 0;

   525         if (n >= base) xbits = extra[n-base];

   526         f = tree[n].Freq;

   527         s->opt_len += (ulg)f * (bits + xbits);

   528         if (stree) s->static_len += (ulg)f * (stree[n].Len + xbits);

   529     }

   530     if (overflow == 0) return;

   531 

   532     Trace((stderr,"\nbit length overflow\n"));

   533     /* This happens for example on obj2 and pic of the Calgary corpus */

   534 

   535     /* Find the first bit length which could increase: */

   536     do {

   537         bits = max_length-1;

   538         while (s->bl_count[bits] == 0) bits--;

   539         s->bl_count[bits]--;      /* move one leaf down the tree */

   540         s->bl_count[bits+1] += 2; /* move one overflow item as its brother */

   541         s->bl_count[max_length]--;

   542         /* The brother of the overflow item also moves one step up,

   543          * but this does not affect bl_count[max_length]

   544          */

   545         overflow -= 2;

   546     } while (overflow > 0);

   547 

   548     /* Now recompute all bit lengths, scanning in increasing frequency.

   549      * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all

   550      * lengths instead of fixing only the wrong ones. This idea is taken

   551      * from 'ar' written by Haruhiko Okumura.)

   552      */

   553     for (bits = max_length; bits != 0; bits--) {

   554         n = s->bl_count[bits];

   555         while (n != 0) {

   556             m = s->heap[--h];

   557             if (m > max_code) continue;

   558             if ((unsigned) tree[m].Len != (unsigned) bits) {

   559                 Trace((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits));

   560                 s->opt_len += ((long)bits - (long)tree[m].Len)

   561                               *(long)tree[m].Freq;

   562                 tree[m].Len = (ush)bits;

   563             }

   564             n--;

   565         }

   566     }

   567 }

   568 

   569 /* ===========================================================================

   570  * Generate the codes for a given tree and bit counts (which need not be

   571  * optimal).

   572  * IN assertion: the array bl_count contains the bit length statistics for

   573  * the given tree and the field len is set for all tree elements.

   574  * OUT assertion: the field code is set for all tree elements of non

   575  *     zero code length.

   576  */

   577 local void gen_codes (tree, max_code, bl_count)

   578     ct_data *tree;             /* the tree to decorate */

   579     int max_code;              /* largest code with non zero frequency */

   580     ushf *bl_count;            /* number of codes at each bit length */

   581 {

   582     ush next_code[MAX_BITS+1]; /* next code value for each bit length */

   583     ush code = 0;              /* running code value */

   584     int bits;                  /* bit index */

   585     int n;                     /* code index */

   586 

   587     /* The distribution counts are first used to generate the code values

   588      * without bit reversal.

   589      */

   590     for (bits = 1; bits <= MAX_BITS; bits++) {

   591         next_code[bits] = code = (code + bl_count[bits-1]) << 1;

   592     }

   593     /* Check that the bit counts in bl_count are consistent. The last code

   594      * must be all ones.

   595      */

   596     Assert (code + bl_count[MAX_BITS]-1 == (1<<MAX_BITS)-1,

   597             "inconsistent bit counts");

   598     Tracev((stderr,"\ngen_codes: max_code %d ", max_code));

   599 

   600     for (n = 0;  n <= max_code; n++) {

   601         int len = tree[n].Len;

   602         if (len == 0) continue;

   603         /* Now reverse the bits */

   604         tree[n].Code = bi_reverse(next_code[len]++, len);

   605 

   606         Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ",

   607              n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len]-1));

   608     }

   609 }

   610 

   611 /* ===========================================================================

   612  * Construct one Huffman tree and assigns the code bit strings and lengths.

   613  * Update the total bit length for the current block.

   614  * IN assertion: the field freq is set for all tree elements.

   615  * OUT assertions: the fields len and code are set to the optimal bit length

   616  *     and corresponding code. The length opt_len is updated; static_len is

   617  *     also updated if stree is not null. The field max_code is set.

   618  */

   619 local void build_tree(s, desc)

   620     deflate_state *s;

   621     tree_desc *desc; /* the tree descriptor */

   622 {

   623     ct_data *tree         = desc->dyn_tree;

   624     const ct_data *stree  = desc->stat_desc->static_tree;

   625     int elems             = desc->stat_desc->elems;

   626     int n, m;          /* iterate over heap elements */

   627     int max_code = -1; /* largest code with non zero frequency */

   628     int node;          /* new node being created */

   629 

   630     /* Construct the initial heap, with least frequent element in

   631      * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1].

   632      * heap[0] is not used.

   633      */

   634     s->heap_len = 0, s->heap_max = HEAP_SIZE;

   635 

   636     for (n = 0; n < elems; n++) {

   637         if (tree[n].Freq != 0) {

   638             s->heap[++(s->heap_len)] = max_code = n;

   639             s->depth[n] = 0;

   640         } else {

   641             tree[n].Len = 0;

   642         }

   643     }

   644 

   645     /* The pkzip format requires that at least one distance code exists,

   646      * and that at least one bit should be sent even if there is only one

   647      * possible code. So to avoid special checks later on we force at least

   648      * two codes of non zero frequency.

   649      */

   650     while (s->heap_len < 2) {

   651         node = s->heap[++(s->heap_len)] = (max_code < 2 ? ++max_code : 0);

   652         tree[node].Freq = 1;

   653         s->depth[node] = 0;

   654         s->opt_len--; if (stree) s->static_len -= stree[node].Len;

   655         /* node is 0 or 1 so it does not have extra bits */

   656     }

   657     desc->max_code = max_code;

   658 

   659     /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree,

   660      * establish sub-heaps of increasing lengths:

   661      */

   662     for (n = s->heap_len/2; n >= 1; n--) pqdownheap(s, tree, n);

   663 

   664     /* Construct the Huffman tree by repeatedly combining the least two

   665      * frequent nodes.

   666      */

   667     node = elems;              /* next internal node of the tree */

   668     do {

   669         pqremove(s, tree, n);  /* n = node of least frequency */

   670         m = s->heap[SMALLEST]; /* m = node of next least frequency */

   671 

   672         s->heap[--(s->heap_max)] = n; /* keep the nodes sorted by frequency */

   673         s->heap[--(s->heap_max)] = m;

   674 

   675         /* Create a new node father of n and m */

   676         tree[node].Freq = tree[n].Freq + tree[m].Freq;

   677         s->depth[node] = (uch)((s->depth[n] >= s->depth[m] ?

   678                                 s->depth[n] : s->depth[m]) + 1);

   679         tree[n].Dad = tree[m].Dad = (ush)node;

   680 #ifdef DUMP_BL_TREE

   681         if (tree == s->bl_tree) {

   682             fprintf(stderr,"\nnode %d(%d), sons %d(%d) %d(%d)",

   683                     node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq);

   684         }

   685 #endif

   686         /* and insert the new node in the heap */

   687         s->heap[SMALLEST] = node++;

   688         pqdownheap(s, tree, SMALLEST);

   689 

   690     } while (s->heap_len >= 2);

   691 

   692     s->heap[--(s->heap_max)] = s->heap[SMALLEST];

   693 

   694     /* At this point, the fields freq and dad are set. We can now

   695      * generate the bit lengths.

   696      */

   697     gen_bitlen(s, (tree_desc *)desc);

   698 

   699     /* The field len is now set, we can generate the bit codes */

   700     gen_codes ((ct_data *)tree, max_code, s->bl_count);

   701 }

   702 

   703 /* ===========================================================================

   704  * Scan a literal or distance tree to determine the frequencies of the codes

   705  * in the bit length tree.

   706  */

   707 local void scan_tree (s, tree, max_code)

   708     deflate_state *s;

   709     ct_data *tree;   /* the tree to be scanned */

   710     int max_code;    /* and its largest code of non zero frequency */

   711 {

   712     int n;                     /* iterates over all tree elements */

   713     int prevlen = -1;          /* last emitted length */

   714     int curlen;                /* length of current code */

   715     int nextlen = tree[0].Len; /* length of next code */

   716     int count = 0;             /* repeat count of the current code */

   717     int max_count = 7;         /* max repeat count */

   718     int min_count = 4;         /* min repeat count */

   719 

   720     if (nextlen == 0) max_count = 138, min_count = 3;

   721     tree[max_code+1].Len = (ush)0xffff; /* guard */

   722 

   723     for (n = 0; n <= max_code; n++) {

   724         curlen = nextlen; nextlen = tree[n+1].Len;

   725         if (++count < max_count && curlen == nextlen) {

   726             continue;

   727         } else if (count < min_count) {

   728             s->bl_tree[curlen].Freq += count;

   729         } else if (curlen != 0) {

   730             if (curlen != prevlen) s->bl_tree[curlen].Freq++;

   731             s->bl_tree[REP_3_6].Freq++;

   732         } else if (count <= 10) {

   733             s->bl_tree[REPZ_3_10].Freq++;

   734         } else {

   735             s->bl_tree[REPZ_11_138].Freq++;

   736         }

   737         count = 0; prevlen = curlen;

   738         if (nextlen == 0) {

   739             max_count = 138, min_count = 3;

   740         } else if (curlen == nextlen) {

   741             max_count = 6, min_count = 3;

   742         } else {

   743             max_count = 7, min_count = 4;

   744         }

   745     }

   746 }

   747 

   748 /* ===========================================================================

   749  * Send a literal or distance tree in compressed form, using the codes in

   750  * bl_tree.

   751  */

   752 local void send_tree (s, tree, max_code)

   753     deflate_state *s;

   754     ct_data *tree; /* the tree to be scanned */

   755     int max_code;       /* and its largest code of non zero frequency */

   756 {

   757     int n;                     /* iterates over all tree elements */

   758     int prevlen = -1;          /* last emitted length */

   759     int curlen;                /* length of current code */

   760     int nextlen = tree[0].Len; /* length of next code */

   761     int count = 0;             /* repeat count of the current code */

   762     int max_count = 7;         /* max repeat count */

   763     int min_count = 4;         /* min repeat count */

   764 

   765     /* tree[max_code+1].Len = -1; */  /* guard already set */

   766     if (nextlen == 0) max_count = 138, min_count = 3;

   767 

   768     for (n = 0; n <= max_code; n++) {

   769         curlen = nextlen; nextlen = tree[n+1].Len;

   770         if (++count < max_count && curlen == nextlen) {

   771             continue;

   772         } else if (count < min_count) {

   773             do { send_code(s, curlen, s->bl_tree); } while (--count != 0);

   774 

   775         } else if (curlen != 0) {

   776             if (curlen != prevlen) {

   777                 send_code(s, curlen, s->bl_tree); count--;

   778             }

   779             Assert(count >= 3 && count <= 6, " 3_6?");

   780             send_code(s, REP_3_6, s->bl_tree); send_bits(s, count-3, 2);

   781 

   782         } else if (count <= 10) {

   783             send_code(s, REPZ_3_10, s->bl_tree); send_bits(s, count-3, 3);

   784 

   785         } else {

   786             send_code(s, REPZ_11_138, s->bl_tree); send_bits(s, count-11, 7);

   787         }

   788         count = 0; prevlen = curlen;

   789         if (nextlen == 0) {

   790             max_count = 138, min_count = 3;

   791         } else if (curlen == nextlen) {

   792             max_count = 6, min_count = 3;

   793         } else {

   794             max_count = 7, min_count = 4;

   795         }

   796     }

   797 }

   798 

   799 /* ===========================================================================

   800  * Construct the Huffman tree for the bit lengths and return the index in

   801  * bl_order of the last bit length code to send.

   802  */

   803 local int build_bl_tree(s)

   804     deflate_state *s;

   805 {

   806     int max_blindex;  /* index of last bit length code of non zero freq */

   807 

   808     /* Determine the bit length frequencies for literal and distance trees */

   809     scan_tree(s, (ct_data *)s->dyn_ltree, s->l_desc.max_code);

   810     scan_tree(s, (ct_data *)s->dyn_dtree, s->d_desc.max_code);

   811 

   812     /* Build the bit length tree: */

   813     build_tree(s, (tree_desc *)(&(s->bl_desc)));

   814     /* opt_len now includes the length of the tree representations, except

   815      * the lengths of the bit lengths codes and the 5+5+4 bits for the counts.

   816      */

   817 

   818     /* Determine the number of bit length codes to send. The pkzip format

   819      * requires that at least 4 bit length codes be sent. (appnote.txt says

   820      * 3 but the actual value used is 4.)

   821      */

   822     for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) {

   823         if (s->bl_tree[bl_order[max_blindex]].Len != 0) break;

   824     }

   825     /* Update opt_len to include the bit length tree and counts */

   826     s->opt_len += 3*(max_blindex+1) + 5+5+4;

   827     Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld",

   828             s->opt_len, s->static_len));

   829 

   830     return max_blindex;

   831 }

   832 

   833 /* ===========================================================================

   834  * Send the header for a block using dynamic Huffman trees: the counts, the

   835  * lengths of the bit length codes, the literal tree and the distance tree.

   836  * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4.

   837  */

   838 local void send_all_trees(s, lcodes, dcodes, blcodes)

   839     deflate_state *s;

   840     int lcodes, dcodes, blcodes; /* number of codes for each tree */

   841 {

   842     int rank;                    /* index in bl_order */

   843 

   844     Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes");

   845     Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES,

   846             "too many codes");

   847     Tracev((stderr, "\nbl counts: "));

   848     send_bits(s, lcodes-257, 5); /* not +255 as stated in appnote.txt */

   849     send_bits(s, dcodes-1,   5);

   850     send_bits(s, blcodes-4,  4); /* not -3 as stated in appnote.txt */

   851     for (rank = 0; rank < blcodes; rank++) {

   852         Tracev((stderr, "\nbl code %2d ", bl_order[rank]));

   853         send_bits(s, s->bl_tree[bl_order[rank]].Len, 3);

   854     }

   855     Tracev((stderr, "\nbl tree: sent %ld", s->bits_sent));

   856 

   857     send_tree(s, (ct_data *)s->dyn_ltree, lcodes-1); /* literal tree */

   858     Tracev((stderr, "\nlit tree: sent %ld", s->bits_sent));

   859 

   860     send_tree(s, (ct_data *)s->dyn_dtree, dcodes-1); /* distance tree */

   861     Tracev((stderr, "\ndist tree: sent %ld", s->bits_sent));

   862 }

   863 

   864 /* ===========================================================================

   865  * Send a stored block

   866  */

   867 void _tr_stored_block(s, buf, stored_len, eof)

   868     deflate_state *s;

   869     charf *buf;       /* input block */

   870     ulg stored_len;   /* length of input block */

   871     int eof;          /* true if this is the last block for a file */

   872 {

   873     send_bits(s, (STORED_BLOCK<<1)+eof, 3);  /* send block type */

   874 #ifdef DEBUG

   875     s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L;

   876     s->compressed_len += (stored_len + 4) << 3;

   877 #endif

   878     copy_block(s, buf, (unsigned)stored_len, 1); /* with header */

   879 }

   880 

   881 /* ===========================================================================

   882  * Send one empty static block to give enough lookahead for inflate.

   883  * This takes 10 bits, of which 7 may remain in the bit buffer.

   884  * The current inflate code requires 9 bits of lookahead. If the

   885  * last two codes for the previous block (real code plus EOB) were coded

   886  * on 5 bits or less, inflate may have only 5+3 bits of lookahead to decode

   887  * the last real code. In this case we send two empty static blocks instead

   888  * of one. (There are no problems if the previous block is stored or fixed.)

   889  * To simplify the code, we assume the worst case of last real code encoded

   890  * on one bit only.

   891  */

   892 void _tr_align(s)

   893     deflate_state *s;

   894 {

   895     send_bits(s, STATIC_TREES<<1, 3);

   896     send_code(s, END_BLOCK, static_ltree);

   897 #ifdef DEBUG

   898     s->compressed_len += 10L; /* 3 for block type, 7 for EOB */

   899 #endif

   900     bi_flush(s);

   901     /* Of the 10 bits for the empty block, we have already sent

   902      * (10 - bi_valid) bits. The lookahead for the last real code (before

   903      * the EOB of the previous block) was thus at least one plus the length

   904      * of the EOB plus what we have just sent of the empty static block.

   905      */

   906     if (1 + s->last_eob_len + 10 - s->bi_valid < 9) {

   907         send_bits(s, STATIC_TREES<<1, 3);

   908         send_code(s, END_BLOCK, static_ltree);

   909 #ifdef DEBUG

   910         s->compressed_len += 10L;

   911 #endif

   912         bi_flush(s);

   913     }

   914     s->last_eob_len = 7;

   915 }

   916 

   917 /* ===========================================================================

   918  * Determine the best encoding for the current block: dynamic trees, static

   919  * trees or store, and output the encoded block to the zip file.

   920  */

   921 void _tr_flush_block(s, buf, stored_len, eof)

   922     deflate_state *s;

   923     charf *buf;       /* input block, or NULL if too old */

   924     ulg stored_len;   /* length of input block */

   925     int eof;          /* true if this is the last block for a file */

   926 {

   927     ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */

   928     int max_blindex = 0;  /* index of last bit length code of non zero freq */

   929 

   930     /* Build the Huffman trees unless a stored block is forced */

   931     if (s->level > 0) {

   932 

   933         /* Check if the file is binary or text */

   934         if (stored_len > 0 && s->strm->data_type == Z_UNKNOWN)

   935             set_data_type(s);

   936 

   937         /* Construct the literal and distance trees */

   938         build_tree(s, (tree_desc *)(&(s->l_desc)));

   939         Tracev((stderr, "\nlit data: dyn %ld, stat %ld", s->opt_len,

   940                 s->static_len));

   941 

   942         build_tree(s, (tree_desc *)(&(s->d_desc)));

   943         Tracev((stderr, "\ndist data: dyn %ld, stat %ld", s->opt_len,

   944                 s->static_len));

   945         /* At this point, opt_len and static_len are the total bit lengths of

   946          * the compressed block data, excluding the tree representations.

   947          */

   948 

   949         /* Build the bit length tree for the above two trees, and get the index

   950          * in bl_order of the last bit length code to send.

   951          */

   952         max_blindex = build_bl_tree(s);

   953 

   954         /* Determine the best encoding. Compute the block lengths in bytes. */

   955         opt_lenb = (s->opt_len+3+7)>>3;

   956         static_lenb = (s->static_len+3+7)>>3;

   957 

   958         Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ",

   959                 opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len,

   960                 s->last_lit));

   961 

   962         if (static_lenb <= opt_lenb) opt_lenb = static_lenb;

   963 

   964     } else {

   965         Assert(buf != (char*)0, "lost buf");

   966         opt_lenb = static_lenb = stored_len + 5; /* force a stored block */

   967     }

   968 

   969 #ifdef FORCE_STORED

   970     if (buf != (char*)0) { /* force stored block */

   971 #else

   972     if (stored_len+4 <= opt_lenb && buf != (char*)0) {

   973                        /* 4: two words for the lengths */

   974 #endif

   975         /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE.

   976          * Otherwise we can't have processed more than WSIZE input bytes since

   977          * the last block flush, because compression would have been

   978          * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to

   979          * transform a block into a stored block.

   980          */

   981         _tr_stored_block(s, buf, stored_len, eof);

   982 

   983 #ifdef FORCE_STATIC

   984     } else if (static_lenb >= 0) { /* force static trees */

   985 #else

   986     } else if (s->strategy == Z_FIXED || static_lenb == opt_lenb) {

   987 #endif

   988         send_bits(s, (STATIC_TREES<<1)+eof, 3);

   989         compress_block(s, (ct_data *)static_ltree, (ct_data *)static_dtree);

   990 #ifdef DEBUG

   991         s->compressed_len += 3 + s->static_len;

   992 #endif

   993     } else {

   994         send_bits(s, (DYN_TREES<<1)+eof, 3);

   995         send_all_trees(s, s->l_desc.max_code+1, s->d_desc.max_code+1,

   996                        max_blindex+1);

   997         compress_block(s, (ct_data *)s->dyn_ltree, (ct_data *)s->dyn_dtree);

   998 #ifdef DEBUG

   999         s->compressed_len += 3 + s->opt_len;

  1000 #endif

  1001     }

  1002     Assert (s->compressed_len == s->bits_sent, "bad compressed size");

  1003     /* The above check is made mod 2^32, for files larger than 512 MB

  1004      * and uLong implemented on 32 bits.

  1005      */

  1006     init_block(s);

  1007 

  1008     if (eof) {

  1009         bi_windup(s);

  1010 #ifdef DEBUG

  1011         s->compressed_len += 7;  /* align on byte boundary */

  1012 #endif

  1013     }

  1014     Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len>>3,

  1015            s->compressed_len-7*eof));

  1016 }

  1017 

  1018 /* ===========================================================================

  1019  * Save the match info and tally the frequency counts. Return true if

  1020  * the current block must be flushed.

  1021  */

  1022 int _tr_tally (s, dist, lc)

  1023     deflate_state *s;

  1024     unsigned dist;  /* distance of matched string */

  1025     unsigned lc;    /* match length-MIN_MATCH or unmatched char (if dist==0) */

  1026 {

  1027     s->d_buf[s->last_lit] = (ush)dist;

  1028     s->l_buf[s->last_lit++] = (uch)lc;

  1029     if (dist == 0) {

  1030         /* lc is the unmatched char */

  1031         s->dyn_ltree[lc].Freq++;

  1032     } else {

  1033         s->matches++;

  1034         /* Here, lc is the match length - MIN_MATCH */

  1035         dist--;             /* dist = match distance - 1 */

  1036         Assert((ush)dist < (ush)MAX_DIST(s) &&

  1037                (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) &&

  1038                (ush)d_code(dist) < (ush)D_CODES,  "_tr_tally: bad match");

  1039 

  1040         s->dyn_ltree[_length_code[lc]+LITERALS+1].Freq++;

  1041         s->dyn_dtree[d_code(dist)].Freq++;

  1042     }

  1043 

  1044 #ifdef TRUNCATE_BLOCK

  1045     /* Try to guess if it is profitable to stop the current block here */

  1046     if ((s->last_lit & 0x1fff) == 0 && s->level > 2) {

  1047         /* Compute an upper bound for the compressed length */

  1048         ulg out_length = (ulg)s->last_lit*8L;

  1049         ulg in_length = (ulg)((long)s->strstart - s->block_start);

  1050         int dcode;

  1051         for (dcode = 0; dcode < D_CODES; dcode++) {

  1052             out_length += (ulg)s->dyn_dtree[dcode].Freq *

  1053                 (5L+extra_dbits[dcode]);

  1054         }

  1055         out_length >>= 3;

  1056         Tracev((stderr,"\nlast_lit %u, in %ld, out ~%ld(%ld%%) ",

  1057                s->last_lit, in_length, out_length,

  1058                100L - out_length*100L/in_length));

  1059         if (s->matches < s->last_lit/2 && out_length < in_length/2) return 1;

  1060     }

  1061 #endif

  1062     return (s->last_lit == s->lit_bufsize-1);

  1063     /* We avoid equality with lit_bufsize because of wraparound at 64K

  1064      * on 16 bit machines and because stored blocks are restricted to

  1065      * 64K-1 bytes.

  1066      */

  1067 }

  1068 

  1069 /* ===========================================================================

  1070  * Send the block data compressed using the given Huffman trees

  1071  */

  1072 local void compress_block(s, ltree, dtree)

  1073     deflate_state *s;

  1074     ct_data *ltree; /* literal tree */

  1075     ct_data *dtree; /* distance tree */

  1076 {

  1077     unsigned dist;      /* distance of matched string */

  1078     int lc;             /* match length or unmatched char (if dist == 0) */

  1079     unsigned lx = 0;    /* running index in l_buf */

  1080     unsigned code;      /* the code to send */

  1081     int extra;          /* number of extra bits to send */

  1082 

  1083     if (s->last_lit != 0) do {

  1084         dist = s->d_buf[lx];

  1085         lc = s->l_buf[lx++];

  1086         if (dist == 0) {

  1087             send_code(s, lc, ltree); /* send a literal byte */

  1088             Tracecv(isgraph(lc), (stderr," '%c' ", lc));

  1089         } else {

  1090             /* Here, lc is the match length - MIN_MATCH */

  1091             code = _length_code[lc];

  1092             send_code(s, code+LITERALS+1, ltree); /* send the length code */

  1093             extra = extra_lbits[code];

  1094             if (extra != 0) {

  1095                 lc -= base_length[code];

  1096                 send_bits(s, lc, extra);       /* send the extra length bits */

  1097             }

  1098             dist--; /* dist is now the match distance - 1 */

  1099             code = d_code(dist);

  1100             Assert (code < D_CODES, "bad d_code");

  1101 

  1102             send_code(s, code, dtree);       /* send the distance code */

  1103             extra = extra_dbits[code];

  1104             if (extra != 0) {

  1105                 dist -= base_dist[code];

  1106                 send_bits(s, dist, extra);   /* send the extra distance bits */

  1107             }

  1108         } /* literal or match pair ? */

  1109 

  1110         /* Check that the overlay between pending_buf and d_buf+l_buf is ok: */

  1111         Assert((uInt)(s->pending) < s->lit_bufsize + 2*lx,

  1112                "pendingBuf overflow");

  1113 

  1114     } while (lx < s->last_lit);

  1115 

  1116     send_code(s, END_BLOCK, ltree);

  1117     s->last_eob_len = ltree[END_BLOCK].Len;

  1118 }

  1119 

  1120 /* ===========================================================================

  1121  * Set the data type to BINARY or TEXT, using a crude approximation:

  1122  * set it to Z_TEXT if all symbols are either printable characters (33 to 255)

  1123  * or white spaces (9 to 13, or 32); or set it to Z_BINARY otherwise.

  1124  * IN assertion: the fields Freq of dyn_ltree are set.

  1125  */

  1126 local void set_data_type(s)

  1127     deflate_state *s;

  1128 {

  1129     int n;

  1130 

  1131     for (n = 0; n < 9; n++)

  1132         if (s->dyn_ltree[n].Freq != 0)

  1133             break;

  1134     if (n == 9)

  1135         for (n = 14; n < 32; n++)