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trees.c-Dateireferenz
#include "deflate.h"
+ Include-Abhängigkeitsdiagramm für trees.c:

gehe zum Quellcode dieser Datei

Datenstrukturen

struct  static_tree_desc_s
 

Makrodefinitionen

#define MAX_BL_BITS   7
 
#define END_BLOCK   256
 
#define REP_3_6   16
 
#define REPZ_3_10   17
 
#define REPZ_11_138   18
 
#define Buf_size   (8 * 2*sizeof(char))
 
#define DIST_CODE_LEN   512 /* see definition of array dist_code below */
 
#define send_code(s, c, tree)   send_bits(s, tree[c].Code, tree[c].Len)
 
#define put_short(s, w)
 
#define send_bits(s, value, length)
 
#define SMALLEST   1
 
#define pqremove(s, tree, top)
 
#define smaller(tree, n, m, depth)
 

Funktionen

local void tr_static_init OF ((void))
 
local void init_block OF ((deflate_state *s))
 
local void pqdownheap OF ((deflate_state *s, ct_data *tree, int k))
 
local void gen_bitlen OF ((deflate_state *s, tree_desc *desc))
 
local void gen_codes OF ((ct_data *tree, int max_code, ushf *bl_count))
 
local void scan_tree OF ((deflate_state *s, ct_data *tree, int max_code))
 
local void send_all_trees OF ((deflate_state *s, int lcodes, int dcodes, int blcodes))
 
local void compress_block OF ((deflate_state *s, ct_data *ltree, ct_data *dtree))
 
local unsigned bi_reverse OF ((unsigned value, int length))
 
local void copy_block OF ((deflate_state *s, charf *buf, unsigned len, int header))
 
local void tr_static_init ()
 
void _tr_init (deflate_state *s)
 
local void init_block (deflate_state *s)
 
local void pqdownheap (deflate_state *s, ct_data *tree, int k)
 
local void gen_bitlen (deflate_state *s, tree_desc *desc)
 
local void gen_codes (ct_data *tree, int max_code, ushf *bl_count)
 
local void build_tree (deflate_state *s, tree_desc *desc)
 
local void scan_tree (deflate_state *s, ct_data *tree, int max_code)
 
local void send_tree (deflate_state *s, ct_data *tree, int max_code)
 
local int build_bl_tree (deflate_state *s)
 
local void send_all_trees (deflate_state *s, int lcodes, int dcodes, int blcodes)
 
void _tr_stored_block (deflate_state *s, charf *buf, ulg stored_len, int eof)
 
void _tr_align (deflate_state *s)
 
void _tr_flush_block (deflate_state *s, charf *buf, ulg stored_len, int eof)
 
int _tr_tally (deflate_state *s, unsigned dist, unsigned lc)
 
local void compress_block (deflate_state *s, ct_data *ltree, ct_data *dtree)
 
local void set_data_type (deflate_state *s)
 
local unsigned bi_reverse (unsigned code, int len)
 
local void bi_flush (deflate_state *s)
 
local void bi_windup (deflate_state *s)
 
local void copy_block (deflate_state *s, charf *buf, unsigned len, int header)
 

Variablen

local const int extra_lbits [LENGTH_CODES] = {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}
 
local const int extra_dbits [D_CODES] = {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}
 
local const int extra_blbits [BL_CODES] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7}
 
local const uch bl_order [BL_CODES] = {16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15}
 
local ct_data static_ltree [L_CODES+2]
 
local ct_data static_dtree [D_CODES]
 
uch _dist_code [DIST_CODE_LEN]
 
uch _length_code [MAX_MATCH-MIN_MATCH+1]
 
local int base_length [LENGTH_CODES]
 
local int base_dist [D_CODES]
 
local static_tree_desc static_l_desc
 
local static_tree_desc static_d_desc
 
local static_tree_desc static_bl_desc
 

Makro-Dokumentation

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

Definiert in Zeile 76 der Datei trees.c.

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

Definiert in Zeile 85 der Datei trees.c.

#define END_BLOCK   256

Definiert in Zeile 49 der Datei trees.c.

#define MAX_BL_BITS   7

Definiert in Zeile 46 der Datei trees.c.

#define pqremove (   s,
  tree,
  top 
)
Wert:
{\
top = s->heap[SMALLEST]; \
s->heap[SMALLEST] = s->heap[s->heap_len--]; \
pqdownheap(s, tree, SMALLEST); \
}

Definiert in Zeile 434 der Datei trees.c.

#define put_short (   s,
  w 
)
Wert:
{ \
put_byte(s, (uch)((w) & 0xff)); \
put_byte(s, (uch)((ush)(w) >> 8)); \
}

Definiert in Zeile 180 der Datei trees.c.

#define REP_3_6   16

Definiert in Zeile 52 der Datei trees.c.

#define REPZ_11_138   18

Definiert in Zeile 58 der Datei trees.c.

#define REPZ_3_10   17

Definiert in Zeile 55 der Datei trees.c.

#define send_bits (   s,
  value,
  length 
)
Wert:
{ int len = length;\
if (s->bi_valid > (int)Buf_size - len) {\
int val = value;\
s->bi_buf |= (val << s->bi_valid);\
put_short(s, s->bi_buf);\
s->bi_buf = (ush)val >> (Buf_size - s->bi_valid);\
s->bi_valid += len - Buf_size;\
} else {\
s->bi_buf |= (value) << s->bi_valid;\
s->bi_valid += len;\
}\
}

Definiert in Zeile 217 der Datei trees.c.

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

Definiert in Zeile 167 der Datei trees.c.

#define smaller (   tree,
  n,
  m,
  depth 
)
Wert:
(tree[n].Freq < tree[m].Freq || \
(tree[n].Freq == tree[m].Freq && depth[n] <= depth[m]))

Definiert in Zeile 445 der Datei trees.c.

#define SMALLEST   1

Definiert in Zeile 426 der Datei trees.c.

Dokumentation der Funktionen

void _tr_align ( deflate_state s)

Definiert in Zeile 892 der Datei trees.c.

894 {
895  send_bits(s, STATIC_TREES<<1, 3);
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);
909 #ifdef DEBUG
910  s->compressed_len += 10L;
911 #endif
912  bi_flush(s);
913  }
914  s->last_eob_len = 7;
915 }
void _tr_flush_block ( deflate_state s,
charf buf,
ulg  stored_len,
int  eof 
)

Definiert in Zeile 921 der Datei trees.c.

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);
990 #ifdef DEBUG
991  s->compressed_len += 3 + s->static_len;
992 #endif
993  } else {
994  send_bits(s, (DYN_TREES<<1)+eof, 3);
996  max_blindex+1);
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 }
void _tr_init ( deflate_state s)

Definiert in Zeile 382 der Datei trees.c.

384 {
385  tr_static_init();
386 
387  s->l_desc.dyn_tree = s->dyn_ltree;
389 
390  s->d_desc.dyn_tree = s->dyn_dtree;
392 
393  s->bl_desc.dyn_tree = s->bl_tree;
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 }
void _tr_stored_block ( deflate_state s,
charf buf,
ulg  stored_len,
int  eof 
)

Definiert in Zeile 867 der Datei trees.c.

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 }
int _tr_tally ( deflate_state s,
unsigned  dist,
unsigned  lc 
)

Definiert in Zeile 1022 der Datei trees.c.

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 }
local void bi_flush ( deflate_state s)

Definiert in Zeile 1161 der Datei trees.c.

1163 {
1164  if (s->bi_valid == 16) {
1165  put_short(s, s->bi_buf);
1166  s->bi_buf = 0;
1167  s->bi_valid = 0;
1168  } else if (s->bi_valid >= 8) {
1169  put_byte(s, (Byte)s->bi_buf);
1170  s->bi_buf >>= 8;
1171  s->bi_valid -= 8;
1172  }
1173 }
local unsigned bi_reverse ( unsigned  code,
int  len 
)

Definiert in Zeile 1146 der Datei trees.c.

1149 {
1150  register unsigned res = 0;
1151  do {
1152  res |= code & 1;
1153  code >>= 1, res <<= 1;
1154  } while (--len > 0);
1155  return res >> 1;
1156 }
local void bi_windup ( deflate_state s)

Definiert in Zeile 1178 der Datei trees.c.

1180 {
1181  if (s->bi_valid > 8) {
1182  put_short(s, s->bi_buf);
1183  } else if (s->bi_valid > 0) {
1184  put_byte(s, (Byte)s->bi_buf);
1185  }
1186  s->bi_buf = 0;
1187  s->bi_valid = 0;
1188 #ifdef DEBUG
1189  s->bits_sent = (s->bits_sent+7) & ~7;
1190 #endif
1191 }
local int build_bl_tree ( deflate_state s)

Definiert in Zeile 803 der Datei trees.c.

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 }
local void build_tree ( deflate_state s,
tree_desc desc 
)

Definiert in Zeile 619 der Datei trees.c.

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 }
local void compress_block ( deflate_state s,
ct_data ltree,
ct_data dtree 
)

Definiert in Zeile 1072 der Datei trees.c.

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 }
local void copy_block ( deflate_state s,
charf buf,
unsigned  len,
int  header 
)

Definiert in Zeile 1197 der Datei trees.c.

1202 {
1203  bi_windup(s); /* align on byte boundary */
1204  s->last_eob_len = 8; /* enough lookahead for inflate */
1205 
1206  if (header) {
1207  put_short(s, (ush)len);
1208  put_short(s, (ush)~len);
1209 #ifdef DEBUG
1210  s->bits_sent += 2*16;
1211 #endif
1212  }
1213 #ifdef DEBUG
1214  s->bits_sent += (ulg)len<<3;
1215 #endif
1216  while (len--) {
1217  put_byte(s, *buf++);
1218  }
1219 }
local void gen_bitlen ( deflate_state s,
tree_desc desc 
)

Definiert in Zeile 490 der Datei trees.c.

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 }
local void gen_codes ( ct_data tree,
int  max_code,
ushf bl_count 
)

Definiert in Zeile 577 der Datei trees.c.

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 }
local void init_block ( deflate_state s)

Definiert in Zeile 411 der Datei trees.c.

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 }
local void tr_static_init OF ( (void)  )
local void init_block OF ( (deflate_state *s )
local void pqdownheap OF ( (deflate_state *s, ct_data *tree, int k)  )
local void gen_bitlen OF ( (deflate_state *s, tree_desc *desc)  )
local void gen_codes OF ( (ct_data *tree, int max_code, ushf *bl_count)  )
local void scan_tree OF ( (deflate_state *s, ct_data *tree, int max_code)  )
local void send_all_trees OF ( (deflate_state *s, int lcodes, int dcodes, int blcodes)  )
local void compress_block OF ( (deflate_state *s, ct_data *ltree, ct_data *dtree)  )
local unsigned bi_reverse OF ( (unsigned value, int length)  )
local void copy_block OF ( (deflate_state *s, charf *buf, unsigned len, int header)  )
local void pqdownheap ( deflate_state s,
ct_data tree,
int  k 
)

Definiert in Zeile 455 der Datei trees.c.

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 }
local void scan_tree ( deflate_state s,
ct_data tree,
int  max_code 
)

Definiert in Zeile 707 der Datei trees.c.

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 }
local void send_all_trees ( deflate_state s,
int  lcodes,
int  dcodes,
int  blcodes 
)

Definiert in Zeile 838 der Datei trees.c.

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 }
local void send_tree ( deflate_state s,
ct_data tree,
int  max_code 
)

Definiert in Zeile 752 der Datei trees.c.

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 }
local void set_data_type ( deflate_state s)

Definiert in Zeile 1126 der Datei trees.c.

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++)
1136  if (s->dyn_ltree[n].Freq != 0)
1137  break;
1138  s->strm->data_type = (n == 32) ? Z_TEXT : Z_BINARY;
1139 }
local void tr_static_init ( )

Definiert in Zeile 238 der Datei trees.c.

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: */
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 }

Variablen-Dokumentation

uch _dist_code[DIST_CODE_LEN]

Definiert in Zeile 102 der Datei trees.c.

uch _length_code[MAX_MATCH-MIN_MATCH+1]

Definiert in Zeile 108 der Datei trees.c.

local int base_dist[D_CODES]

Definiert in Zeile 114 der Datei trees.c.

local int base_length[LENGTH_CODES]

Definiert in Zeile 111 der Datei trees.c.

local const uch bl_order[BL_CODES] = {16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15}

Definiert in Zeile 71 der Datei trees.c.

local const int extra_blbits[BL_CODES] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7}

Definiert in Zeile 68 der Datei trees.c.

local const int extra_dbits[D_CODES] = {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}

Definiert in Zeile 65 der Datei trees.c.

local const int extra_lbits[LENGTH_CODES] = {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}

Definiert in Zeile 62 der Datei trees.c.

local static_tree_desc static_bl_desc
Initialisierung:

Definiert in Zeile 135 der Datei trees.c.

local static_tree_desc static_d_desc
Initialisierung:

Definiert in Zeile 132 der Datei trees.c.

local ct_data static_dtree[D_CODES]

Definiert in Zeile 97 der Datei trees.c.

local static_tree_desc static_l_desc
Initialisierung:

Definiert in Zeile 129 der Datei trees.c.

local ct_data static_ltree[L_CODES+2]

Definiert in Zeile 90 der Datei trees.c.