CHDK_DE Vorschauversion  Trunk Rev. 5279
 Alle Datenstrukturen Dateien Funktionen Variablen Typdefinitionen Aufzählungen Aufzählungswerte Makrodefinitionen
deflate.c-Dateireferenz
#include "deflate.h"
+ Include-Abhängigkeitsdiagramm für deflate.c:

gehe zum Quellcode dieser Datei

Datenstrukturen

struct  config_s
 
struct  static_tree_desc_s
 

Makrodefinitionen

#define NIL   0
 
#define TOO_FAR   4096
 
#define MIN_LOOKAHEAD   (MAX_MATCH+MIN_MATCH+1)
 
#define EQUAL   0
 
#define UPDATE_HASH(s, h, c)   (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask)
 
#define INSERT_STRING(s, str, match_head)
 
#define CLEAR_HASH(s)
 
#define check_match(s, start, match, length)
 
#define FLUSH_BLOCK_ONLY(s, eof)
 
#define FLUSH_BLOCK(s, eof)
 

Typdefinitionen

typedef block_state compress_func OF ((deflate_state *s, int flush))
 
typedef struct config_s config
 

Aufzählungen

enum  block_state { need_more, block_done, finish_started, finish_done }
 

Funktionen

local void fill_window OF ((deflate_state *s))
 
local block_state deflate_stored OF ((deflate_state *s, int flush))
 
local void putShortMSB OF ((deflate_state *s, uInt b))
 
local void flush_pending OF ((z_streamp strm))
 
local int read_buf OF ((z_streamp strm, Bytef *buf, unsigned size))
 
local uInt longest_match OF ((deflate_state *s, IPos cur_match))
 
int ZEXPORT deflateInit_ (z_streamp strm, int level, const char *version, int stream_size)
 
int ZEXPORT deflateInit2_ (z_streamp strm, int level, int method, int windowBits, int memLevel, int strategy, const char *version, int stream_size)
 
int ZEXPORT deflateSetDictionary (z_streamp strm, const Bytef *dictionary, uInt dictLength)
 
int ZEXPORT deflateReset (z_streamp strm)
 
int ZEXPORT deflateSetHeader (z_streamp strm, gz_headerp head)
 
int ZEXPORT deflatePrime (z_streamp strm, int bits, int value)
 
int ZEXPORT deflateParams (z_streamp strm, int level, int strategy)
 
int ZEXPORT deflateTune (z_streamp strm, int good_length, int max_lazy, int nice_length, int max_chain)
 
uLong ZEXPORT deflateBound (z_streamp strm, uLong sourceLen)
 
local void putShortMSB (deflate_state *s, uInt b)
 
local void flush_pending (z_streamp strm)
 
int ZEXPORT deflate (z_streamp strm, int flush)
 
int ZEXPORT deflateEnd (z_streamp strm)
 
int ZEXPORT deflateCopy (z_streamp dest, z_streamp source)
 
local int read_buf (z_streamp strm, Bytef *buf, unsigned size)
 
local void lm_init (deflate_state *s)
 
local uInt longest_match (deflate_state *s, IPos cur_match)
 
local uInt longest_match_fast (deflate_state *s, IPos cur_match)
 
local void fill_window (deflate_state *s)
 
local block_state deflate_stored (deflate_state *s, int flush)
 
local block_state deflate_fast (deflate_state *s, int flush)
 
local block_state deflate_slow (deflate_state *s, int flush)
 

Variablen

const char deflate_copyright []
 
local const config configuration_table [10]
 

Makro-Dokumentation

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

Definiert in Zeile 1253 der Datei deflate.c.

#define CLEAR_HASH (   s)
Wert:
s->head[s->hash_size-1] = NIL; \
zmemzero((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head));

Definiert in Zeile 199 der Datei deflate.c.

#define EQUAL   0

Definiert in Zeile 157 der Datei deflate.c.

#define FLUSH_BLOCK (   s,
  eof 
)
Wert:
{ \
FLUSH_BLOCK_ONLY(s, eof); \
if (s->strm->avail_out == 0) return (eof) ? finish_started : need_more; \
}

Definiert in Zeile 1376 der Datei deflate.c.

#define FLUSH_BLOCK_ONLY (   s,
  eof 
)
Wert:
{ \
_tr_flush_block(s, (s->block_start >= 0L ? \
(charf *)&s->window[(unsigned)s->block_start] : \
(charf *)Z_NULL), \
(ulg)((long)s->strstart - s->block_start), \
(eof)); \
s->block_start = s->strstart; \
flush_pending(s->strm); \
Tracev((stderr,"[FLUSH]")); \
}

Definiert in Zeile 1364 der Datei deflate.c.

#define INSERT_STRING (   s,
  str,
  match_head 
)
Wert:
(UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \
s->head[s->ins_h] = (Pos)(str))

Definiert in Zeile 189 der Datei deflate.c.

#define MIN_LOOKAHEAD   (MAX_MATCH+MIN_MATCH+1)

Definiert in Zeile 113 der Datei deflate.c.

#define NIL   0

Definiert in Zeile 105 der Datei deflate.c.

#define TOO_FAR   4096

Definiert in Zeile 109 der Datei deflate.c.

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

Definiert in Zeile 170 der Datei deflate.c.

Dokumentation der benutzerdefinierten Typen

typedef struct config_s config

Definiert in Zeile 73 der Datei deflate.c.

Dokumentation der Aufzählungstypen

Aufzählungswerte
need_more 
block_done 
finish_started 
finish_done 

Definiert in Zeile 66 der Datei deflate.c.

66  {
67  need_more, /* block not completed, need more input or more output */
68  block_done, /* block flush performed */
69  finish_started, /* finish started, need only more output at next deflate */
70  finish_done /* finish done, accept no more input or output */
71 } block_state;

Dokumentation der Funktionen

int ZEXPORT deflate ( z_streamp  strm,
int  flush 
)

Definiert in Zeile 552 der Datei deflate.c.

555 {
556  int old_flush; /* value of flush param for previous deflate call */
557  deflate_state *s;
558 
559  if (strm == Z_NULL || strm->state == Z_NULL ||
560  flush > Z_FINISH || flush < 0) {
561  return Z_STREAM_ERROR;
562  }
563  s = strm->state;
564 
565  if (strm->next_out == Z_NULL ||
566  (strm->next_in == Z_NULL && strm->avail_in != 0) ||
567  (s->status == FINISH_STATE && flush != Z_FINISH)) {
568  ERR_RETURN(strm, Z_STREAM_ERROR);
569  }
570  if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR);
571 
572  s->strm = strm; /* just in case */
573  old_flush = s->last_flush;
574  s->last_flush = flush;
575 
576  /* Write the header */
577  if (s->status == INIT_STATE) {
578 #ifdef GZIP
579  if (s->wrap == 2) {
580  strm->adler = crc32(0L, Z_NULL, 0);
581  put_byte(s, 31);
582  put_byte(s, 139);
583  put_byte(s, 8);
584  if (s->gzhead == NULL) {
585  put_byte(s, 0);
586  put_byte(s, 0);
587  put_byte(s, 0);
588  put_byte(s, 0);
589  put_byte(s, 0);
590  put_byte(s, s->level == 9 ? 2 :
591  (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
592  4 : 0));
593  put_byte(s, OS_CODE);
594  s->status = BUSY_STATE;
595  }
596  else {
597  put_byte(s, (s->gzhead->text ? 1 : 0) +
598  (s->gzhead->hcrc ? 2 : 0) +
599  (s->gzhead->extra == Z_NULL ? 0 : 4) +
600  (s->gzhead->name == Z_NULL ? 0 : 8) +
601  (s->gzhead->comment == Z_NULL ? 0 : 16)
602  );
603  put_byte(s, (Byte)(s->gzhead->time & 0xff));
604  put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff));
605  put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff));
606  put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff));
607  put_byte(s, s->level == 9 ? 2 :
608  (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
609  4 : 0));
610  put_byte(s, s->gzhead->os & 0xff);
611  if (s->gzhead->extra != NULL) {
612  put_byte(s, s->gzhead->extra_len & 0xff);
613  put_byte(s, (s->gzhead->extra_len >> 8) & 0xff);
614  }
615  if (s->gzhead->hcrc)
616  strm->adler = crc32(strm->adler, s->pending_buf,
617  s->pending);
618  s->gzindex = 0;
619  s->status = EXTRA_STATE;
620  }
621  }
622  else
623 #endif
624  {
625  uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8;
626  uInt level_flags;
627 
628  if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2)
629  level_flags = 0;
630  else if (s->level < 6)
631  level_flags = 1;
632  else if (s->level == 6)
633  level_flags = 2;
634  else
635  level_flags = 3;
636  header |= (level_flags << 6);
637  if (s->strstart != 0) header |= PRESET_DICT;
638  header += 31 - (header % 31);
639 
640  s->status = BUSY_STATE;
641  putShortMSB(s, header);
642 
643  /* Save the adler32 of the preset dictionary: */
644  if (s->strstart != 0) {
645  putShortMSB(s, (uInt)(strm->adler >> 16));
646  putShortMSB(s, (uInt)(strm->adler & 0xffff));
647  }
648  strm->adler = adler32(0L, Z_NULL, 0);
649  }
650  }
651 #ifdef GZIP
652  if (s->status == EXTRA_STATE) {
653  if (s->gzhead->extra != NULL) {
654  uInt beg = s->pending; /* start of bytes to update crc */
655 
656  while (s->gzindex < (s->gzhead->extra_len & 0xffff)) {
657  if (s->pending == s->pending_buf_size) {
658  if (s->gzhead->hcrc && s->pending > beg)
659  strm->adler = crc32(strm->adler, s->pending_buf + beg,
660  s->pending - beg);
661  flush_pending(strm);
662  beg = s->pending;
663  if (s->pending == s->pending_buf_size)
664  break;
665  }
666  put_byte(s, s->gzhead->extra[s->gzindex]);
667  s->gzindex++;
668  }
669  if (s->gzhead->hcrc && s->pending > beg)
670  strm->adler = crc32(strm->adler, s->pending_buf + beg,
671  s->pending - beg);
672  if (s->gzindex == s->gzhead->extra_len) {
673  s->gzindex = 0;
674  s->status = NAME_STATE;
675  }
676  }
677  else
678  s->status = NAME_STATE;
679  }
680  if (s->status == NAME_STATE) {
681  if (s->gzhead->name != NULL) {
682  uInt beg = s->pending; /* start of bytes to update crc */
683  int val;
684 
685  do {
686  if (s->pending == s->pending_buf_size) {
687  if (s->gzhead->hcrc && s->pending > beg)
688  strm->adler = crc32(strm->adler, s->pending_buf + beg,
689  s->pending - beg);
690  flush_pending(strm);
691  beg = s->pending;
692  if (s->pending == s->pending_buf_size) {
693  val = 1;
694  break;
695  }
696  }
697  val = s->gzhead->name[s->gzindex++];
698  put_byte(s, val);
699  } while (val != 0);
700  if (s->gzhead->hcrc && s->pending > beg)
701  strm->adler = crc32(strm->adler, s->pending_buf + beg,
702  s->pending - beg);
703  if (val == 0) {
704  s->gzindex = 0;
705  s->status = COMMENT_STATE;
706  }
707  }
708  else
709  s->status = COMMENT_STATE;
710  }
711  if (s->status == COMMENT_STATE) {
712  if (s->gzhead->comment != NULL) {
713  uInt beg = s->pending; /* start of bytes to update crc */
714  int val;
715 
716  do {
717  if (s->pending == s->pending_buf_size) {
718  if (s->gzhead->hcrc && s->pending > beg)
719  strm->adler = crc32(strm->adler, s->pending_buf + beg,
720  s->pending - beg);
721  flush_pending(strm);
722  beg = s->pending;
723  if (s->pending == s->pending_buf_size) {
724  val = 1;
725  break;
726  }
727  }
728  val = s->gzhead->comment[s->gzindex++];
729  put_byte(s, val);
730  } while (val != 0);
731  if (s->gzhead->hcrc && s->pending > beg)
732  strm->adler = crc32(strm->adler, s->pending_buf + beg,
733  s->pending - beg);
734  if (val == 0)
735  s->status = HCRC_STATE;
736  }
737  else
738  s->status = HCRC_STATE;
739  }
740  if (s->status == HCRC_STATE) {
741  if (s->gzhead->hcrc) {
742  if (s->pending + 2 > s->pending_buf_size)
743  flush_pending(strm);
744  if (s->pending + 2 <= s->pending_buf_size) {
745  put_byte(s, (Byte)(strm->adler & 0xff));
746  put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
747  strm->adler = crc32(0L, Z_NULL, 0);
748  s->status = BUSY_STATE;
749  }
750  }
751  else
752  s->status = BUSY_STATE;
753  }
754 #endif
755 
756  /* Flush as much pending output as possible */
757  if (s->pending != 0) {
758  flush_pending(strm);
759  if (strm->avail_out == 0) {
760  /* Since avail_out is 0, deflate will be called again with
761  * more output space, but possibly with both pending and
762  * avail_in equal to zero. There won't be anything to do,
763  * but this is not an error situation so make sure we
764  * return OK instead of BUF_ERROR at next call of deflate:
765  */
766  s->last_flush = -1;
767  return Z_OK;
768  }
769 
770  /* Make sure there is something to do and avoid duplicate consecutive
771  * flushes. For repeated and useless calls with Z_FINISH, we keep
772  * returning Z_STREAM_END instead of Z_BUF_ERROR.
773  */
774  } else if (strm->avail_in == 0 && flush <= old_flush &&
775  flush != Z_FINISH) {
776  ERR_RETURN(strm, Z_BUF_ERROR);
777  }
778 
779  /* User must not provide more input after the first FINISH: */
780  if (s->status == FINISH_STATE && strm->avail_in != 0) {
781  ERR_RETURN(strm, Z_BUF_ERROR);
782  }
783 
784  /* Start a new block or continue the current one.
785  */
786  if (strm->avail_in != 0 || s->lookahead != 0 ||
787  (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) {
788  block_state bstate;
789 
790  bstate = (*(configuration_table[s->level].func))(s, flush);
791 
792  if (bstate == finish_started || bstate == finish_done) {
793  s->status = FINISH_STATE;
794  }
795  if (bstate == need_more || bstate == finish_started) {
796  if (strm->avail_out == 0) {
797  s->last_flush = -1; /* avoid BUF_ERROR next call, see above */
798  }
799  return Z_OK;
800  /* If flush != Z_NO_FLUSH && avail_out == 0, the next call
801  * of deflate should use the same flush parameter to make sure
802  * that the flush is complete. So we don't have to output an
803  * empty block here, this will be done at next call. This also
804  * ensures that for a very small output buffer, we emit at most
805  * one empty block.
806  */
807  }
808  if (bstate == block_done) {
809  if (flush == Z_PARTIAL_FLUSH) {
810  _tr_align(s);
811  } else { /* FULL_FLUSH or SYNC_FLUSH */
812  _tr_stored_block(s, (char*)0, 0L, 0);
813  /* For a full flush, this empty block will be recognized
814  * as a special marker by inflate_sync().
815  */
816  if (flush == Z_FULL_FLUSH) {
817  CLEAR_HASH(s); /* forget history */
818  }
819  }
820  flush_pending(strm);
821  if (strm->avail_out == 0) {
822  s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */
823  return Z_OK;
824  }
825  }
826  }
827  Assert(strm->avail_out > 0, "bug2");
828 
829  if (flush != Z_FINISH) return Z_OK;
830  if (s->wrap <= 0) return Z_STREAM_END;
831 
832  /* Write the trailer */
833 #ifdef GZIP
834  if (s->wrap == 2) {
835  put_byte(s, (Byte)(strm->adler & 0xff));
836  put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
837  put_byte(s, (Byte)((strm->adler >> 16) & 0xff));
838  put_byte(s, (Byte)((strm->adler >> 24) & 0xff));
839  put_byte(s, (Byte)(strm->total_in & 0xff));
840  put_byte(s, (Byte)((strm->total_in >> 8) & 0xff));
841  put_byte(s, (Byte)((strm->total_in >> 16) & 0xff));
842  put_byte(s, (Byte)((strm->total_in >> 24) & 0xff));
843  }
844  else
845 #endif
846  {
847  putShortMSB(s, (uInt)(strm->adler >> 16));
848  putShortMSB(s, (uInt)(strm->adler & 0xffff));
849  }
850  flush_pending(strm);
851  /* If avail_out is zero, the application will call deflate again
852  * to flush the rest.
853  */
854  if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */
855  return s->pending != 0 ? Z_OK : Z_STREAM_END;
856 }
local block_state deflate_fast ( deflate_state s,
int  flush 
)

Definiert in Zeile 1448 der Datei deflate.c.

1451 {
1452  IPos hash_head = NIL; /* head of the hash chain */
1453  int bflush; /* set if current block must be flushed */
1454 
1455  for (;;) {
1456  /* Make sure that we always have enough lookahead, except
1457  * at the end of the input file. We need MAX_MATCH bytes
1458  * for the next match, plus MIN_MATCH bytes to insert the
1459  * string following the next match.
1460  */
1461  if (s->lookahead < MIN_LOOKAHEAD) {
1462  fill_window(s);
1463  if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
1464  return need_more;
1465  }
1466  if (s->lookahead == 0) break; /* flush the current block */
1467  }
1468 
1469  /* Insert the string window[strstart .. strstart+2] in the
1470  * dictionary, and set hash_head to the head of the hash chain:
1471  */
1472  if (s->lookahead >= MIN_MATCH) {
1473  INSERT_STRING(s, s->strstart, hash_head);
1474  }
1475 
1476  /* Find the longest match, discarding those <= prev_length.
1477  * At this point we have always match_length < MIN_MATCH
1478  */
1479  if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) {
1480  /* To simplify the code, we prevent matches with the string
1481  * of window index 0 (in particular we have to avoid a match
1482  * of the string with itself at the start of the input file).
1483  */
1484 #ifdef FASTEST
1485  if ((s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) ||
1486  (s->strategy == Z_RLE && s->strstart - hash_head == 1)) {
1487  s->match_length = longest_match_fast (s, hash_head);
1488  }
1489 #else
1490  if (s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) {
1491  s->match_length = longest_match (s, hash_head);
1492  } else if (s->strategy == Z_RLE && s->strstart - hash_head == 1) {
1493  s->match_length = longest_match_fast (s, hash_head);
1494  }
1495 #endif
1496  /* longest_match() or longest_match_fast() sets match_start */
1497  }
1498  if (s->match_length >= MIN_MATCH) {
1500 
1501  _tr_tally_dist(s, s->strstart - s->match_start,
1502  s->match_length - MIN_MATCH, bflush);
1503 
1504  s->lookahead -= s->match_length;
1505 
1506  /* Insert new strings in the hash table only if the match length
1507  * is not too large. This saves time but degrades compression.
1508  */
1509 #ifndef FASTEST
1510  if (s->match_length <= s->max_insert_length &&
1511  s->lookahead >= MIN_MATCH) {
1512  s->match_length--; /* string at strstart already in table */
1513  do {
1514  s->strstart++;
1515  INSERT_STRING(s, s->strstart, hash_head);
1516  /* strstart never exceeds WSIZE-MAX_MATCH, so there are
1517  * always MIN_MATCH bytes ahead.
1518  */
1519  } while (--s->match_length != 0);
1520  s->strstart++;
1521  } else
1522 #endif
1523  {
1524  s->strstart += s->match_length;
1525  s->match_length = 0;
1526  s->ins_h = s->window[s->strstart];
1527  UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);
1528 #if MIN_MATCH != 3
1529  Call UPDATE_HASH() MIN_MATCH-3 more times
1530 #endif
1531  /* If lookahead < MIN_MATCH, ins_h is garbage, but it does not
1532  * matter since it will be recomputed at next deflate call.
1533  */
1534  }
1535  } else {
1536  /* No match, output a literal byte */
1537  Tracevv((stderr,"%c", s->window[s->strstart]));
1538  _tr_tally_lit (s, s->window[s->strstart], bflush);
1539  s->lookahead--;
1540  s->strstart++;
1541  }
1542  if (bflush) FLUSH_BLOCK(s, 0);
1543  }
1544  FLUSH_BLOCK(s, flush == Z_FINISH);
1545  return flush == Z_FINISH ? finish_done : block_done;
1546 }
local block_state deflate_slow ( deflate_state s,
int  flush 
)

Definiert in Zeile 1554 der Datei deflate.c.

1557 {
1558  IPos hash_head = NIL; /* head of hash chain */
1559  int bflush; /* set if current block must be flushed */
1560 
1561  /* Process the input block. */
1562  for (;;) {
1563  /* Make sure that we always have enough lookahead, except
1564  * at the end of the input file. We need MAX_MATCH bytes
1565  * for the next match, plus MIN_MATCH bytes to insert the
1566  * string following the next match.
1567  */
1568  if (s->lookahead < MIN_LOOKAHEAD) {
1569  fill_window(s);
1570  if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
1571  return need_more;
1572  }
1573  if (s->lookahead == 0) break; /* flush the current block */
1574  }
1575 
1576  /* Insert the string window[strstart .. strstart+2] in the
1577  * dictionary, and set hash_head to the head of the hash chain:
1578  */
1579  if (s->lookahead >= MIN_MATCH) {
1580  INSERT_STRING(s, s->strstart, hash_head);
1581  }
1582 
1583  /* Find the longest match, discarding those <= prev_length.
1584  */
1586  s->match_length = MIN_MATCH-1;
1587 
1588  if (hash_head != NIL && s->prev_length < s->max_lazy_match &&
1589  s->strstart - hash_head <= MAX_DIST(s)) {
1590  /* To simplify the code, we prevent matches with the string
1591  * of window index 0 (in particular we have to avoid a match
1592  * of the string with itself at the start of the input file).
1593  */
1594  if (s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) {
1595  s->match_length = longest_match (s, hash_head);
1596  } else if (s->strategy == Z_RLE && s->strstart - hash_head == 1) {
1597  s->match_length = longest_match_fast (s, hash_head);
1598  }
1599  /* longest_match() or longest_match_fast() sets match_start */
1600 
1601  if (s->match_length <= 5 && (s->strategy == Z_FILTERED
1602 #if TOO_FAR <= 32767
1603  || (s->match_length == MIN_MATCH &&
1604  s->strstart - s->match_start > TOO_FAR)
1605 #endif
1606  )) {
1607 
1608  /* If prev_match is also MIN_MATCH, match_start is garbage
1609  * but we will ignore the current match anyway.
1610  */
1611  s->match_length = MIN_MATCH-1;
1612  }
1613  }
1614  /* If there was a match at the previous step and the current
1615  * match is not better, output the previous match:
1616  */
1617  if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) {
1618  uInt max_insert = s->strstart + s->lookahead - MIN_MATCH;
1619  /* Do not insert strings in hash table beyond this. */
1620 
1621  check_match(s, s->strstart-1, s->prev_match, s->prev_length);
1622 
1623  _tr_tally_dist(s, s->strstart -1 - s->prev_match,
1624  s->prev_length - MIN_MATCH, bflush);
1625 
1626  /* Insert in hash table all strings up to the end of the match.
1627  * strstart-1 and strstart are already inserted. If there is not
1628  * enough lookahead, the last two strings are not inserted in
1629  * the hash table.
1630  */
1631  s->lookahead -= s->prev_length-1;
1632  s->prev_length -= 2;
1633  do {
1634  if (++s->strstart <= max_insert) {
1635  INSERT_STRING(s, s->strstart, hash_head);
1636  }
1637  } while (--s->prev_length != 0);
1638  s->match_available = 0;
1639  s->match_length = MIN_MATCH-1;
1640  s->strstart++;
1641 
1642  if (bflush) FLUSH_BLOCK(s, 0);
1643 
1644  } else if (s->match_available) {
1645  /* If there was no match at the previous position, output a
1646  * single literal. If there was a match but the current match
1647  * is longer, truncate the previous match to a single literal.
1648  */
1649  Tracevv((stderr,"%c", s->window[s->strstart-1]));
1650  _tr_tally_lit(s, s->window[s->strstart-1], bflush);
1651  if (bflush) {
1652  FLUSH_BLOCK_ONLY(s, 0);
1653  }
1654  s->strstart++;
1655  s->lookahead--;
1656  if (s->strm->avail_out == 0) return need_more;
1657  } else {
1658  /* There is no previous match to compare with, wait for
1659  * the next step to decide.
1660  */
1661  s->match_available = 1;
1662  s->strstart++;
1663  s->lookahead--;
1664  }
1665  }
1666  Assert (flush != Z_NO_FLUSH, "no flush?");
1667  if (s->match_available) {
1668  Tracevv((stderr,"%c", s->window[s->strstart-1]));
1669  _tr_tally_lit(s, s->window[s->strstart-1], bflush);
1670  s->match_available = 0;
1671  }
1672  FLUSH_BLOCK(s, flush == Z_FINISH);
1673  return flush == Z_FINISH ? finish_done : block_done;
1674 }
local block_state deflate_stored ( deflate_state s,
int  flush 
)

Definiert in Zeile 1390 der Datei deflate.c.

1393 {
1394  /* Stored blocks are limited to 0xffff bytes, pending_buf is limited
1395  * to pending_buf_size, and each stored block has a 5 byte header:
1396  */
1397  ulg max_block_size = 0xffff;
1398  ulg max_start;
1399 
1400  if (max_block_size > s->pending_buf_size - 5) {
1401  max_block_size = s->pending_buf_size - 5;
1402  }
1403 
1404  /* Copy as much as possible from input to output: */
1405  for (;;) {
1406  /* Fill the window as much as possible: */
1407  if (s->lookahead <= 1) {
1408 
1409  Assert(s->strstart < s->w_size+MAX_DIST(s) ||
1410  s->block_start >= (long)s->w_size, "slide too late");
1411 
1412  fill_window(s);
1413  if (s->lookahead == 0 && flush == Z_NO_FLUSH) return need_more;
1414 
1415  if (s->lookahead == 0) break; /* flush the current block */
1416  }
1417  Assert(s->block_start >= 0L, "block gone");
1418 
1419  s->strstart += s->lookahead;
1420  s->lookahead = 0;
1421 
1422  /* Emit a stored block if pending_buf will be full: */
1423  max_start = s->block_start + max_block_size;
1424  if (s->strstart == 0 || (ulg)s->strstart >= max_start) {
1425  /* strstart == 0 is possible when wraparound on 16-bit machine */
1426  s->lookahead = (uInt)(s->strstart - max_start);
1427  s->strstart = (uInt)max_start;
1428  FLUSH_BLOCK(s, 0);
1429  }
1430  /* Flush if we may have to slide, otherwise block_start may become
1431  * negative and the data will be gone:
1432  */
1433  if (s->strstart - (uInt)s->block_start >= MAX_DIST(s)) {
1434  FLUSH_BLOCK(s, 0);
1435  }
1436  }
1437  FLUSH_BLOCK(s, flush == Z_FINISH);
1438  return flush == Z_FINISH ? finish_done : block_done;
1439 }
uLong ZEXPORT deflateBound ( z_streamp  strm,
uLong  sourceLen 
)

Definiert in Zeile 489 der Datei deflate.c.

492 {
493  deflate_state *s;
494  uLong destLen;
495 
496  /* conservative upper bound */
497  destLen = sourceLen +
498  ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 11;
499 
500  /* if can't get parameters, return conservative bound */
501  if (strm == Z_NULL || strm->state == Z_NULL)
502  return destLen;
503 
504  /* if not default parameters, return conservative bound */
505  s = strm->state;
506  if (s->w_bits != 15 || s->hash_bits != 8 + 7)
507  return destLen;
508 
509  /* default settings: return tight bound for that case */
510  return compressBound(sourceLen);
511 }
int ZEXPORT deflateCopy ( z_streamp  dest,
z_streamp  source 
)

Definiert in Zeile 894 der Datei deflate.c.

897 {
898 #ifdef MAXSEG_64K
899  return Z_STREAM_ERROR;
900 #else
901  deflate_state *ds;
902  deflate_state *ss;
903  ushf *overlay;
904 
905 
906  if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL) {
907  return Z_STREAM_ERROR;
908  }
909 
910  ss = source->state;
911 
912  zmemcpy(dest, source, sizeof(z_stream));
913 
914  ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state));
915  if (ds == Z_NULL) return Z_MEM_ERROR;
916  dest->state = (struct internal_state FAR *) ds;
917  zmemcpy(ds, ss, sizeof(deflate_state));
918  ds->strm = dest;
919 
920  ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte));
921  ds->prev = (Posf *) ZALLOC(dest, ds->w_size, sizeof(Pos));
922  ds->head = (Posf *) ZALLOC(dest, ds->hash_size, sizeof(Pos));
923  overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2);
924  ds->pending_buf = (uchf *) overlay;
925 
926  if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL ||
927  ds->pending_buf == Z_NULL) {
928  deflateEnd (dest);
929  return Z_MEM_ERROR;
930  }
931  /* following zmemcpy do not work for 16-bit MSDOS */
932  zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte));
933  zmemcpy(ds->prev, ss->prev, ds->w_size * sizeof(Pos));
934  zmemcpy(ds->head, ss->head, ds->hash_size * sizeof(Pos));
936 
937  ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf);
938  ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush);
939  ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize;
940 
941  ds->l_desc.dyn_tree = ds->dyn_ltree;
942  ds->d_desc.dyn_tree = ds->dyn_dtree;
943  ds->bl_desc.dyn_tree = ds->bl_tree;
944 
945  return Z_OK;
946 #endif /* MAXSEG_64K */
947 }
int ZEXPORT deflateEnd ( z_streamp  strm)

Definiert in Zeile 859 der Datei deflate.c.

861 {
862  int status;
863 
864  if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
865 
866  status = strm->state->status;
867  if (status != INIT_STATE &&
868  status != EXTRA_STATE &&
869  status != NAME_STATE &&
870  status != COMMENT_STATE &&
871  status != HCRC_STATE &&
872  status != BUSY_STATE &&
873  status != FINISH_STATE) {
874  return Z_STREAM_ERROR;
875  }
876 
877  /* Deallocate in reverse order of allocations: */
878  TRY_FREE(strm, strm->state->pending_buf);
879  TRY_FREE(strm, strm->state->head);
880  TRY_FREE(strm, strm->state->prev);
881  TRY_FREE(strm, strm->state->window);
882 
883  ZFREE(strm, strm->state);
884  strm->state = Z_NULL;
885 
886  return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK;
887 }
int ZEXPORT deflateInit2_ ( z_streamp  strm,
int  level,
int  method,
int  windowBits,
int  memLevel,
int  strategy,
const char *  version,
int  stream_size 
)

Definiert in Zeile 216 der Datei deflate.c.

226 {
227  deflate_state *s;
228  int wrap = 1;
229  static const char my_version[] = ZLIB_VERSION;
230 
231  ushf *overlay;
232  /* We overlay pending_buf and d_buf+l_buf. This works since the average
233  * output size for (length,distance) codes is <= 24 bits.
234  */
235 
236  if (version == Z_NULL || version[0] != my_version[0] ||
237  stream_size != sizeof(z_stream)) {
238  return Z_VERSION_ERROR;
239  }
240  if (strm == Z_NULL) return Z_STREAM_ERROR;
241 
242  strm->msg = Z_NULL;
243  if (strm->zalloc == (alloc_func)0) {
244  strm->zalloc = zcalloc;
245  strm->opaque = (voidpf)0;
246  }
247  if (strm->zfree == (free_func)0) strm->zfree = zcfree;
248 
249 #ifdef FASTEST
250  if (level != 0) level = 1;
251 #else
252  if (level == Z_DEFAULT_COMPRESSION) level = 6;
253 #endif
254 
255  if (windowBits < 0) { /* suppress zlib wrapper */
256  wrap = 0;
257  windowBits = -windowBits;
258  }
259 #ifdef GZIP
260  else if (windowBits > 15) {
261  wrap = 2; /* write gzip wrapper instead */
262  windowBits -= 16;
263  }
264 #endif
265  if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED ||
266  windowBits < 8 || windowBits > 15 || level < 0 || level > 9 ||
267  strategy < 0 || strategy > Z_FIXED) {
268  return Z_STREAM_ERROR;
269  }
270  if (windowBits == 8) windowBits = 9; /* until 256-byte window bug fixed */
271  s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state));
272  if (s == Z_NULL) return Z_MEM_ERROR;
273  strm->state = (struct internal_state FAR *)s;
274  s->strm = strm;
275 
276  s->wrap = wrap;
277  s->gzhead = Z_NULL;
278  s->w_bits = windowBits;
279  s->w_size = 1 << s->w_bits;
280  s->w_mask = s->w_size - 1;
281 
282  s->hash_bits = memLevel + 7;
283  s->hash_size = 1 << s->hash_bits;
284  s->hash_mask = s->hash_size - 1;
285  s->hash_shift = ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH);
286 
287  s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte));
288  s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos));
289  s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos));
290 
291  s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */
292 
293  overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2);
294  s->pending_buf = (uchf *) overlay;
295  s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L);
296 
297  if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL ||
298  s->pending_buf == Z_NULL) {
299  s->status = FINISH_STATE;
300  strm->msg = (char*)ERR_MSG(Z_MEM_ERROR);
301  deflateEnd (strm);
302  return Z_MEM_ERROR;
303  }
304  s->d_buf = overlay + s->lit_bufsize/sizeof(ush);
305  s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize;
306 
307  s->level = level;
308  s->strategy = strategy;
309  s->method = (Byte)method;
310 
311  return deflateReset(strm);
312 }
int ZEXPORT deflateInit_ ( z_streamp  strm,
int  level,
const char *  version,
int  stream_size 
)

Definiert in Zeile 204 der Datei deflate.c.

209 {
211  Z_DEFAULT_STRATEGY, version, stream_size);
212  /* To do: ignore strm->next_in if we use it as window */
213 }
int ZEXPORT deflateParams ( z_streamp  strm,
int  level,
int  strategy 
)

Definiert in Zeile 416 der Datei deflate.c.

420 {
421  deflate_state *s;
422  compress_func func;
423  int err = Z_OK;
424 
425  if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
426  s = strm->state;
427 
428 #ifdef FASTEST
429  if (level != 0) level = 1;
430 #else
431  if (level == Z_DEFAULT_COMPRESSION) level = 6;
432 #endif
433  if (level < 0 || level > 9 || strategy < 0 || strategy > Z_FIXED) {
434  return Z_STREAM_ERROR;
435  }
436  func = configuration_table[s->level].func;
437 
438  if (func != configuration_table[level].func && strm->total_in != 0) {
439  /* Flush the last buffer: */
440  err = deflate(strm, Z_PARTIAL_FLUSH);
441  }
442  if (s->level != level) {
443  s->level = level;
448  }
449  s->strategy = strategy;
450  return err;
451 }
int ZEXPORT deflatePrime ( z_streamp  strm,
int  bits,
int  value 
)

Definiert in Zeile 404 der Datei deflate.c.

408 {
409  if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
410  strm->state->bi_valid = bits;
411  strm->state->bi_buf = (ush)(value & ((1 << bits) - 1));
412  return Z_OK;
413 }
int ZEXPORT deflateReset ( z_streamp  strm)

Definiert in Zeile 357 der Datei deflate.c.

359 {
360  deflate_state *s;
361 
362  if (strm == Z_NULL || strm->state == Z_NULL ||
363  strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0) {
364  return Z_STREAM_ERROR;
365  }
366 
367  strm->total_in = strm->total_out = 0;
368  strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */
369  strm->data_type = Z_UNKNOWN;
370 
371  s = (deflate_state *)strm->state;
372  s->pending = 0;
373  s->pending_out = s->pending_buf;
374 
375  if (s->wrap < 0) {
376  s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */
377  }
378  s->status = s->wrap ? INIT_STATE : BUSY_STATE;
379  strm->adler =
380 #ifdef GZIP
381  s->wrap == 2 ? crc32(0L, Z_NULL, 0) :
382 #endif
383  adler32(0L, Z_NULL, 0);
384  s->last_flush = Z_NO_FLUSH;
385 
386  _tr_init(s);
387  lm_init(s);
388 
389  return Z_OK;
390 }
int ZEXPORT deflateSetDictionary ( z_streamp  strm,
const Bytef dictionary,
uInt  dictLength 
)

Definiert in Zeile 315 der Datei deflate.c.

319 {
320  deflate_state *s;
321  uInt length = dictLength;
322  uInt n;
323  IPos hash_head = 0;
324 
325  if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL ||
326  strm->state->wrap == 2 ||
327  (strm->state->wrap == 1 && strm->state->status != INIT_STATE))
328  return Z_STREAM_ERROR;
329 
330  s = strm->state;
331  if (s->wrap)
332  strm->adler = adler32(strm->adler, dictionary, dictLength);
333 
334  if (length < MIN_MATCH) return Z_OK;
335  if (length > MAX_DIST(s)) {
336  length = MAX_DIST(s);
337  dictionary += dictLength - length; /* use the tail of the dictionary */
338  }
339  zmemcpy(s->window, dictionary, length);
340  s->strstart = length;
341  s->block_start = (long)length;
342 
343  /* Insert all strings in the hash table (except for the last two bytes).
344  * s->lookahead stays null, so s->ins_h will be recomputed at the next
345  * call of fill_window.
346  */
347  s->ins_h = s->window[0];
348  UPDATE_HASH(s, s->ins_h, s->window[1]);
349  for (n = 0; n <= length - MIN_MATCH; n++) {
350  INSERT_STRING(s, n, hash_head);
351  }
352  if (hash_head) hash_head = 0; /* to make compiler happy */
353  return Z_OK;
354 }
int ZEXPORT deflateSetHeader ( z_streamp  strm,
gz_headerp  head 
)

Definiert in Zeile 393 der Datei deflate.c.

396 {
397  if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
398  if (strm->state->wrap != 2) return Z_STREAM_ERROR;
399  strm->state->gzhead = head;
400  return Z_OK;
401 }
int ZEXPORT deflateTune ( z_streamp  strm,
int  good_length,
int  max_lazy,
int  nice_length,
int  max_chain 
)

Definiert in Zeile 454 der Datei deflate.c.

460 {
461  deflate_state *s;
462 
463  if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
464  s = strm->state;
465  s->good_match = good_length;
466  s->max_lazy_match = max_lazy;
467  s->nice_match = nice_length;
468  s->max_chain_length = max_chain;
469  return Z_OK;
470 }
local void fill_window ( deflate_state s)

Definiert in Zeile 1266 der Datei deflate.c.

1268 {
1269  register unsigned n, m;
1270  register Posf *p;
1271  unsigned more; /* Amount of free space at the end of the window. */
1272  uInt wsize = s->w_size;
1273 
1274  do {
1275  more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart);
1276 
1277  /* Deal with !@#$% 64K limit: */
1278  if (sizeof(int) <= 2) {
1279  if (more == 0 && s->strstart == 0 && s->lookahead == 0) {
1280  more = wsize;
1281 
1282  } else if (more == (unsigned)(-1)) {
1283  /* Very unlikely, but possible on 16 bit machine if
1284  * strstart == 0 && lookahead == 1 (input done a byte at time)
1285  */
1286  more--;
1287  }
1288  }
1289 
1290  /* If the window is almost full and there is insufficient lookahead,
1291  * move the upper half to the lower one to make room in the upper half.
1292  */
1293  if (s->strstart >= wsize+MAX_DIST(s)) {
1294 
1295  zmemcpy(s->window, s->window+wsize, (unsigned)wsize);
1296  s->match_start -= wsize;
1297  s->strstart -= wsize; /* we now have strstart >= MAX_DIST */
1298  s->block_start -= (long) wsize;
1299 
1300  /* Slide the hash table (could be avoided with 32 bit values
1301  at the expense of memory usage). We slide even when level == 0
1302  to keep the hash table consistent if we switch back to level > 0
1303  later. (Using level 0 permanently is not an optimal usage of
1304  zlib, so we don't care about this pathological case.)
1305  */
1306  /* %%% avoid this when Z_RLE */
1307  n = s->hash_size;
1308  p = &s->head[n];
1309  do {
1310  m = *--p;
1311  *p = (Pos)(m >= wsize ? m-wsize : NIL);
1312  } while (--n);
1313 
1314  n = wsize;
1315 #ifndef FASTEST
1316  p = &s->prev[n];
1317  do {
1318  m = *--p;
1319  *p = (Pos)(m >= wsize ? m-wsize : NIL);
1320  /* If n is not on any hash chain, prev[n] is garbage but
1321  * its value will never be used.
1322  */
1323  } while (--n);
1324 #endif
1325  more += wsize;
1326  }
1327  if (s->strm->avail_in == 0) return;
1328 
1329  /* If there was no sliding:
1330  * strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 &&
1331  * more == window_size - lookahead - strstart
1332  * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1)
1333  * => more >= window_size - 2*WSIZE + 2
1334  * In the BIG_MEM or MMAP case (not yet supported),
1335  * window_size == input_size + MIN_LOOKAHEAD &&
1336  * strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD.
1337  * Otherwise, window_size == 2*WSIZE so more >= 2.
1338  * If there was sliding, more >= WSIZE. So in all cases, more >= 2.
1339  */
1340  Assert(more >= 2, "more < 2");
1341 
1342  n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more);
1343  s->lookahead += n;
1344 
1345  /* Initialize the hash value now that we have some input: */
1346  if (s->lookahead >= MIN_MATCH) {
1347  s->ins_h = s->window[s->strstart];
1348  UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);
1349 #if MIN_MATCH != 3
1350  Call UPDATE_HASH() MIN_MATCH-3 more times
1351 #endif
1352  }
1353  /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage,
1354  * but this is not important since only literal bytes will be emitted.
1355  */
1356 
1357  } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0);
1358 }
local void flush_pending ( z_streamp  strm)

Definiert in Zeile 532 der Datei deflate.c.

534 {
535  unsigned len = strm->state->pending;
536 
537  if (len > strm->avail_out) len = strm->avail_out;
538  if (len == 0) return;
539 
540  zmemcpy(strm->next_out, strm->state->pending_out, len);
541  strm->next_out += len;
542  strm->state->pending_out += len;
543  strm->total_out += len;
544  strm->avail_out -= len;
545  strm->state->pending -= len;
546  if (strm->state->pending == 0) {
547  strm->state->pending_out = strm->state->pending_buf;
548  }
549 }
local void lm_init ( deflate_state s)

Definiert in Zeile 986 der Datei deflate.c.

988 {
989  s->window_size = (ulg)2L*s->w_size;
990 
991  CLEAR_HASH(s);
992 
993  /* Set the default configuration parameters:
994  */
999 
1000  s->strstart = 0;
1001  s->block_start = 0L;
1002  s->lookahead = 0;
1003  s->match_length = s->prev_length = MIN_MATCH-1;
1004  s->match_available = 0;
1005  s->ins_h = 0;
1006 #ifndef FASTEST
1007 #ifdef ASMV
1008  match_init(); /* initialize the asm code */
1009 #endif
1010 #endif
1011 }
local uInt longest_match ( deflate_state s,
IPos  cur_match 
)

Definiert in Zeile 1027 der Datei deflate.c.

1030 {
1031  unsigned chain_length = s->max_chain_length;/* max hash chain length */
1032  register Bytef *scan = s->window + s->strstart; /* current string */
1033  register Bytef *match; /* matched string */
1034  register int len; /* length of current match */
1035  int best_len = s->prev_length; /* best match length so far */
1036  int nice_match = s->nice_match; /* stop if match long enough */
1037  IPos limit = s->strstart > (IPos)MAX_DIST(s) ?
1038  s->strstart - (IPos)MAX_DIST(s) : NIL;
1039  /* Stop when cur_match becomes <= limit. To simplify the code,
1040  * we prevent matches with the string of window index 0.
1041  */
1042  Posf *prev = s->prev;
1043  uInt wmask = s->w_mask;
1044 
1045 #ifdef UNALIGNED_OK
1046  /* Compare two bytes at a time. Note: this is not always beneficial.
1047  * Try with and without -DUNALIGNED_OK to check.
1048  */
1049  register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1;
1050  register ush scan_start = *(ushf*)scan;
1051  register ush scan_end = *(ushf*)(scan+best_len-1);
1052 #else
1053  register Bytef *strend = s->window + s->strstart + MAX_MATCH;
1054  register Byte scan_end1 = scan[best_len-1];
1055  register Byte scan_end = scan[best_len];
1056 #endif
1057 
1058  /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
1059  * It is easy to get rid of this optimization if necessary.
1060  */
1061  Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
1062 
1063  /* Do not waste too much time if we already have a good match: */
1064  if (s->prev_length >= s->good_match) {
1065  chain_length >>= 2;
1066  }
1067  /* Do not look for matches beyond the end of the input. This is necessary
1068  * to make deflate deterministic.
1069  */
1070  if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead;
1071 
1072  Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
1073 
1074  do {
1075  Assert(cur_match < s->strstart, "no future");
1076  match = s->window + cur_match;
1077 
1078  /* Skip to next match if the match length cannot increase
1079  * or if the match length is less than 2. Note that the checks below
1080  * for insufficient lookahead only occur occasionally for performance
1081  * reasons. Therefore uninitialized memory will be accessed, and
1082  * conditional jumps will be made that depend on those values.
1083  * However the length of the match is limited to the lookahead, so
1084  * the output of deflate is not affected by the uninitialized values.
1085  */
1086 #if (defined(UNALIGNED_OK) && MAX_MATCH == 258)
1087  /* This code assumes sizeof(unsigned short) == 2. Do not use
1088  * UNALIGNED_OK if your compiler uses a different size.
1089  */
1090  if (*(ushf*)(match+best_len-1) != scan_end ||
1091  *(ushf*)match != scan_start) continue;
1092 
1093  /* It is not necessary to compare scan[2] and match[2] since they are
1094  * always equal when the other bytes match, given that the hash keys
1095  * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at
1096  * strstart+3, +5, ... up to strstart+257. We check for insufficient
1097  * lookahead only every 4th comparison; the 128th check will be made
1098  * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is
1099  * necessary to put more guard bytes at the end of the window, or
1100  * to check more often for insufficient lookahead.
1101  */
1102  Assert(scan[2] == match[2], "scan[2]?");
1103  scan++, match++;
1104  do {
1105  } while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
1106  *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
1107  *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
1108  *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
1109  scan < strend);
1110  /* The funny "do {}" generates better code on most compilers */
1111 
1112  /* Here, scan <= window+strstart+257 */
1113  Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
1114  if (*scan == *match) scan++;
1115 
1116  len = (MAX_MATCH - 1) - (int)(strend-scan);
1117  scan = strend - (MAX_MATCH-1);
1118 
1119 #else /* UNALIGNED_OK */
1120 
1121  if (match[best_len] != scan_end ||
1122  match[best_len-1] != scan_end1 ||
1123  *match != *scan ||
1124  *++match != scan[1]) continue;
1125 
1126  /* The check at best_len-1 can be removed because it will be made
1127  * again later. (This heuristic is not always a win.)
1128  * It is not necessary to compare scan[2] and match[2] since they
1129  * are always equal when the other bytes match, given that
1130  * the hash keys are equal and that HASH_BITS >= 8.
1131  */
1132  scan += 2, match++;
1133  Assert(*scan == *match, "match[2]?");
1134 
1135  /* We check for insufficient lookahead only every 8th comparison;
1136  * the 256th check will be made at strstart+258.
1137  */
1138  do {
1139  } while (*++scan == *++match && *++scan == *++match &&
1140  *++scan == *++match && *++scan == *++match &&
1141  *++scan == *++match && *++scan == *++match &&
1142  *++scan == *++match && *++scan == *++match &&
1143  scan < strend);
1144 
1145  Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
1146 
1147  len = MAX_MATCH - (int)(strend - scan);
1148  scan = strend - MAX_MATCH;
1149 
1150 #endif /* UNALIGNED_OK */
1151 
1152  if (len > best_len) {
1153  s->match_start = cur_match;
1154  best_len = len;
1155  if (len >= nice_match) break;
1156 #ifdef UNALIGNED_OK
1157  scan_end = *(ushf*)(scan+best_len-1);
1158 #else
1159  scan_end1 = scan[best_len-1];
1160  scan_end = scan[best_len];
1161 #endif
1162  }
1163  } while ((cur_match = prev[cur_match & wmask]) > limit
1164  && --chain_length != 0);
1165 
1166  if ((uInt)best_len <= s->lookahead) return (uInt)best_len;
1167  return s->lookahead;
1168 }
local uInt longest_match_fast ( deflate_state s,
IPos  cur_match 
)

Definiert in Zeile 1175 der Datei deflate.c.

1178 {
1179  register Bytef *scan = s->window + s->strstart; /* current string */
1180  register Bytef *match; /* matched string */
1181  register int len; /* length of current match */
1182  register Bytef *strend = s->window + s->strstart + MAX_MATCH;
1183 
1184  /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
1185  * It is easy to get rid of this optimization if necessary.
1186  */
1187  Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
1188 
1189  Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
1190 
1191  Assert(cur_match < s->strstart, "no future");
1192 
1193  match = s->window + cur_match;
1194 
1195  /* Return failure if the match length is less than 2:
1196  */
1197  if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1;
1198 
1199  /* The check at best_len-1 can be removed because it will be made
1200  * again later. (This heuristic is not always a win.)
1201  * It is not necessary to compare scan[2] and match[2] since they
1202  * are always equal when the other bytes match, given that
1203  * the hash keys are equal and that HASH_BITS >= 8.
1204  */
1205  scan += 2, match += 2;
1206  Assert(*scan == *match, "match[2]?");
1207 
1208  /* We check for insufficient lookahead only every 8th comparison;
1209  * the 256th check will be made at strstart+258.
1210  */
1211  do {
1212  } while (*++scan == *++match && *++scan == *++match &&
1213  *++scan == *++match && *++scan == *++match &&
1214  *++scan == *++match && *++scan == *++match &&
1215  *++scan == *++match && *++scan == *++match &&
1216  scan < strend);
1217 
1218  Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
1219 
1220  len = MAX_MATCH - (int)(strend - scan);
1221 
1222  if (len < MIN_MATCH) return MIN_MATCH - 1;
1223 
1224  s->match_start = cur_match;
1225  return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead;
1226 }
local void fill_window OF ( (deflate_state *s )
local void putShortMSB OF ( (deflate_state *s, uInt b)  )
local void flush_pending OF ( (z_streamp strm)  )
local int read_buf OF ( (z_streamp strm, Bytef *buf, unsigned size)  )
local uInt longest_match OF ( (deflate_state *s, IPos cur_match)  )
local void putShortMSB ( deflate_state s,
uInt  b 
)

Definiert in Zeile 518 der Datei deflate.c.

521 {
522  put_byte(s, (Byte)(b >> 8));
523  put_byte(s, (Byte)(b & 0xff));
524 }
local int read_buf ( z_streamp  strm,
Bytef buf,
unsigned  size 
)

Definiert in Zeile 956 der Datei deflate.c.

960 {
961  unsigned len = strm->avail_in;
962 
963  if (len > size) len = size;
964  if (len == 0) return 0;
965 
966  strm->avail_in -= len;
967 
968  if (strm->state->wrap == 1) {
969  strm->adler = adler32(strm->adler, strm->next_in, len);
970  }
971 #ifdef GZIP
972  else if (strm->state->wrap == 2) {
973  strm->adler = crc32(strm->adler, strm->next_in, len);
974  }
975 #endif
976  zmemcpy(buf, strm->next_in, len);
977  strm->next_in += len;
978  strm->total_in += len;
979 
980  return (int)len;
981 }

Variablen-Dokumentation

local const config configuration_table[10]
Initialisierung:
= {
{0, 0, 0, 0, deflate_stored},
{4, 4, 8, 4, deflate_fast},
{4, 5, 16, 8, deflate_fast},
{4, 6, 32, 32, deflate_fast},
{4, 4, 16, 16, deflate_slow},
{8, 16, 32, 32, deflate_slow},
{8, 16, 128, 128, deflate_slow},
{8, 32, 128, 256, deflate_slow},
{32, 128, 258, 1024, deflate_slow},
{32, 258, 258, 4096, deflate_slow}}

Definiert in Zeile 137 der Datei deflate.c.

const char deflate_copyright[]
Initialisierung:
=
" deflate 1.2.3 Copyright 1995-2005 Jean-loup Gailly "

Definiert in Zeile 54 der Datei deflate.c.