#include "deflate.h"

Include dependency graph for deflate.cc:

Classes
struct	config_s

struct	static_tree_desc_s

Macros
#define	NIL 0

#define	TOO_FAR 4096

#define	EQUAL 0

#define	RANK(f) (((f) << 1) - ((f) > 4 ? 9 : 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, last)

#define	FLUSH_BLOCK(s, last)

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

typedef struct config_s	config

Enumerations
enum	block_state { need_more, block_done, finish_started, finish_done }

Functions
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	deflateResetKeep (z_streamp strm)

int ZEXPORT	deflateReset (z_streamp strm)

int ZEXPORT	deflateSetHeader (z_streamp strm, gz_headerp head)

int ZEXPORT	deflatePending (z_streamp strm, unsigned pending, int bits)

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 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)

local block_state	deflate_rle (deflate_state *s, int flush)

local block_state	deflate_huff (deflate_state *s, int flush)

Variables
local const config	configuration_table [10]

Macro Definition Documentation

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

Definition at line 1323 of file deflate.cc.

#define CLEAR_HASH ( s )

Value:

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

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

NIL

#define NIL

Definition: deflate.cc:104

s

const XML_Char * s

Definition: expat.h:262

zmemzero

void ZLIB_INTERNAL zmemzero(Bytef *dest, uInt len)

Definition: zutil.cc:168

Definition at line 196 of file deflate.cc.

#define EQUAL 0

Definition at line 151 of file deflate.cc.

#define FLUSH_BLOCK	(	s,
		last
	)

Value:

{ \
   FLUSH_BLOCK_ONLY(s, last); \
   if (s->strm->avail_out == 0) return (last) ? finish_started : need_more; \
}

Definition at line 1495 of file deflate.cc.

#define FLUSH_BLOCK_ONLY	(	s,
		last
	)

Value:

{ \
   _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), \
                (last)); \
   s->block_start = s->strstart; \
   flush_pending(s->strm); \
   Tracev((stderr,"[FLUSH]")); \
}

Definition at line 1483 of file deflate.cc.

#define INSERT_STRING	(	s,
		str,
		match_head
	)

Value:

(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))

Definition at line 186 of file deflate.cc.

#define NIL 0

Definition at line 104 of file deflate.cc.

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

Definition at line 159 of file deflate.cc.

#define TOO_FAR 4096

Definition at line 108 of file deflate.cc.

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

Definition at line 167 of file deflate.cc.

Typedef Documentation

typedef struct config_s config

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

Definition at line 73 of file deflate.cc.

Enumeration Type Documentation

enum block_state

Enumerator
need_more
block_done
finish_started
finish_done

Definition at line 66 of file deflate.cc.

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

Function Documentation

int ZEXPORT deflate	(	z_streamp	strm,
		int	flush
	)

Definition at line 627 of file deflate.cc.

 {
     int old_flush; /* value of flush param for previous deflate call */
     deflate_state *s;
 
     if (strm == Z_NULL || strm->state == Z_NULL ||
         flush > Z_BLOCK || flush < 0) {
         return Z_STREAM_ERROR;
     }
     s = strm->state;
 
     if (strm->next_out == Z_NULL ||
         (strm->next_in == Z_NULL && strm->avail_in != 0) ||
         (s->status == FINISH_STATE && flush != Z_FINISH)) {
         ERR_RETURN(strm, Z_STREAM_ERROR);
     }
     if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR);
 
     s->strm = strm; /* just in case */
     old_flush = s->last_flush;
     s->last_flush = flush;
 
     /* Write the header */
     if (s->status == INIT_STATE) {
 #ifdef GZIP
         if (s->wrap == 2) {
             strm->adler = crc32(0L, Z_NULL, 0);
             put_byte(s, 31);
             put_byte(s, 139);
             put_byte(s, 8);
             if (s->gzhead == Z_NULL) {
                 put_byte(s, 0);
                 put_byte(s, 0);
                 put_byte(s, 0);
                 put_byte(s, 0);
                 put_byte(s, 0);
                 put_byte(s, s->level == 9 ? 2 :
                             (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
                              4 : 0));
                 put_byte(s, OS_CODE);
                 s->status = BUSY_STATE;
             }
             else {
                 put_byte(s, (s->gzhead->text ? 1 : 0) +
                             (s->gzhead->hcrc ? 2 : 0) +
                             (s->gzhead->extra == Z_NULL ? 0 : 4) +
                             (s->gzhead->name == Z_NULL ? 0 : 8) +
                             (s->gzhead->comment == Z_NULL ? 0 : 16)
                         );
                 put_byte(s, (Byte)(s->gzhead->time & 0xff));
                 put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff));
                 put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff));
                 put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff));
                 put_byte(s, s->level == 9 ? 2 :
                             (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
                              4 : 0));
                 put_byte(s, s->gzhead->os & 0xff);
                 if (s->gzhead->extra != Z_NULL) {
                     put_byte(s, s->gzhead->extra_len & 0xff);
                     put_byte(s, (s->gzhead->extra_len >> 8) & 0xff);
                 }
                 if (s->gzhead->hcrc)
                     strm->adler = crc32(strm->adler, s->pending_buf,
                                         s->pending);
                 s->gzindex = 0;
                 s->status = EXTRA_STATE;
             }
         }
         else
 #endif
         {
             uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8;
             uInt level_flags;
 
             if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2)
                 level_flags = 0;
             else if (s->level < 6)
                 level_flags = 1;
             else if (s->level == 6)
                 level_flags = 2;
             else
                 level_flags = 3;
             header |= (level_flags << 6);
             if (s->strstart != 0) header |= PRESET_DICT;
             header += 31 - (header % 31);
 
             s->status = BUSY_STATE;
             putShortMSB(s, header);
 
             /* Save the adler32 of the preset dictionary: */
             if (s->strstart != 0) {
                 putShortMSB(s, (uInt)(strm->adler >> 16));
                 putShortMSB(s, (uInt)(strm->adler & 0xffff));
             }
             strm->adler = adler32(0L, Z_NULL, 0);
         }
     }
 #ifdef GZIP
     if (s->status == EXTRA_STATE) {
         if (s->gzhead->extra != Z_NULL) {
             uInt beg = s->pending;  /* start of bytes to update crc */
 
             while (s->gzindex < (s->gzhead->extra_len & 0xffff)) {
                 if (s->pending == s->pending_buf_size) {
                     if (s->gzhead->hcrc && s->pending > beg)
                         strm->adler = crc32(strm->adler, s->pending_buf + beg,
                                             s->pending - beg);
                     flush_pending(strm);
                     beg = s->pending;
                     if (s->pending == s->pending_buf_size)
                         break;
                 }
                 put_byte(s, s->gzhead->extra[s->gzindex]);
                 s->gzindex++;
             }
             if (s->gzhead->hcrc && s->pending > beg)
                 strm->adler = crc32(strm->adler, s->pending_buf + beg,
                                     s->pending - beg);
             if (s->gzindex == s->gzhead->extra_len) {
                 s->gzindex = 0;
                 s->status = NAME_STATE;
             }
         }
         else
             s->status = NAME_STATE;
     }
     if (s->status == NAME_STATE) {
         if (s->gzhead->name != Z_NULL) {
             uInt beg = s->pending;  /* start of bytes to update crc */
             int val;
 
             do {
                 if (s->pending == s->pending_buf_size) {
                     if (s->gzhead->hcrc && s->pending > beg)
                         strm->adler = crc32(strm->adler, s->pending_buf + beg,
                                             s->pending - beg);
                     flush_pending(strm);
                     beg = s->pending;
                     if (s->pending == s->pending_buf_size) {
                         val = 1;
                         break;
                     }
                 }
                 val = s->gzhead->name[s->gzindex++];
                 put_byte(s, val);
             } while (val != 0);
             if (s->gzhead->hcrc && s->pending > beg)
                 strm->adler = crc32(strm->adler, s->pending_buf + beg,
                                     s->pending - beg);
             if (val == 0) {
                 s->gzindex = 0;
                 s->status = COMMENT_STATE;
             }
         }
         else
             s->status = COMMENT_STATE;
     }
     if (s->status == COMMENT_STATE) {
         if (s->gzhead->comment != Z_NULL) {
             uInt beg = s->pending;  /* start of bytes to update crc */
             int val;
 
             do {
                 if (s->pending == s->pending_buf_size) {
                     if (s->gzhead->hcrc && s->pending > beg)
                         strm->adler = crc32(strm->adler, s->pending_buf + beg,
                                             s->pending - beg);
                     flush_pending(strm);
                     beg = s->pending;
                     if (s->pending == s->pending_buf_size) {
                         val = 1;
                         break;
                     }
                 }
                 val = s->gzhead->comment[s->gzindex++];
                 put_byte(s, val);
             } while (val != 0);
             if (s->gzhead->hcrc && s->pending > beg)
                 strm->adler = crc32(strm->adler, s->pending_buf + beg,
                                     s->pending - beg);
             if (val == 0)
                 s->status = HCRC_STATE;
         }
         else
             s->status = HCRC_STATE;
     }
     if (s->status == HCRC_STATE) {
         if (s->gzhead->hcrc) {
             if (s->pending + 2 > s->pending_buf_size)
                 flush_pending(strm);
             if (s->pending + 2 <= s->pending_buf_size) {
                 put_byte(s, (Byte)(strm->adler & 0xff));
                 put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
                 strm->adler = crc32(0L, Z_NULL, 0);
                 s->status = BUSY_STATE;
             }
         }
         else
             s->status = BUSY_STATE;
     }
 #endif
 
     /* Flush as much pending output as possible */
     if (s->pending != 0) {
         flush_pending(strm);
         if (strm->avail_out == 0) {
             /* Since avail_out is 0, deflate will be called again with
              * more output space, but possibly with both pending and
              * avail_in equal to zero. There won't be anything to do,
              * but this is not an error situation so make sure we
              * return OK instead of BUF_ERROR at next call of deflate:
              */
             s->last_flush = -1;
             return Z_OK;
         }
 
     /* Make sure there is something to do and avoid duplicate consecutive
      * flushes. For repeated and useless calls with Z_FINISH, we keep
      * returning Z_STREAM_END instead of Z_BUF_ERROR.
      */
     } else if (strm->avail_in == 0 && RANK(flush) <= RANK(old_flush) &&
                flush != Z_FINISH) {
         ERR_RETURN(strm, Z_BUF_ERROR);
     }
 
     /* User must not provide more input after the first FINISH: */
     if (s->status == FINISH_STATE && strm->avail_in != 0) {
         ERR_RETURN(strm, Z_BUF_ERROR);
     }
 
     /* Start a new block or continue the current one.
      */
     if (strm->avail_in != 0 || s->lookahead != 0 ||
         (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) {
         block_state bstate;
 
         bstate = s->strategy == Z_HUFFMAN_ONLY ? deflate_huff(s, flush) :
                     (s->strategy == Z_RLE ? deflate_rle(s, flush) :
                         (*(configuration_table[s->level].func))(s, flush));
 
         if (bstate == finish_started || bstate == finish_done) {
             s->status = FINISH_STATE;
         }
         if (bstate == need_more || bstate == finish_started) {
             if (strm->avail_out == 0) {
                 s->last_flush = -1; /* avoid BUF_ERROR next call, see above */
             }
             return Z_OK;
             /* If flush != Z_NO_FLUSH && avail_out == 0, the next call
              * of deflate should use the same flush parameter to make sure
              * that the flush is complete. So we don't have to output an
              * empty block here, this will be done at next call. This also
              * ensures that for a very small output buffer, we emit at most
              * one empty block.
              */
         }
         if (bstate == block_done) {
             if (flush == Z_PARTIAL_FLUSH) {
                 _tr_align(s);
             } else if (flush != Z_BLOCK) { /* FULL_FLUSH or SYNC_FLUSH */
                 _tr_stored_block(s, (char*)0, 0L, 0);
                 /* For a full flush, this empty block will be recognized
                  * as a special marker by inflate_sync().
                  */
                 if (flush == Z_FULL_FLUSH) {
                     CLEAR_HASH(s);             /* forget history */
                     if (s->lookahead == 0) {
                         s->strstart = 0;
                         s->block_start = 0L;
                         s->insert = 0;
                     }
                 }
             }
             flush_pending(strm);
             if (strm->avail_out == 0) {
               s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */
               return Z_OK;
             }
         }
     }
     Assert(strm->avail_out > 0, "bug2");
 
     if (flush != Z_FINISH) return Z_OK;
     if (s->wrap <= 0) return Z_STREAM_END;
 
     /* Write the trailer */
 #ifdef GZIP
     if (s->wrap == 2) {
         put_byte(s, (Byte)(strm->adler & 0xff));
         put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
         put_byte(s, (Byte)((strm->adler >> 16) & 0xff));
         put_byte(s, (Byte)((strm->adler >> 24) & 0xff));
         put_byte(s, (Byte)(strm->total_in & 0xff));
         put_byte(s, (Byte)((strm->total_in >> 8) & 0xff));
         put_byte(s, (Byte)((strm->total_in >> 16) & 0xff));
         put_byte(s, (Byte)((strm->total_in >> 24) & 0xff));
     }
     else
 #endif
     {
         putShortMSB(s, (uInt)(strm->adler >> 16));
         putShortMSB(s, (uInt)(strm->adler & 0xffff));
     }
     flush_pending(strm);
     /* If avail_out is zero, the application will call deflate again
      * to flush the rest.
      */
     if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */
     return s->pending != 0 ? Z_OK : Z_STREAM_END;
 }

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local block_state deflate_fast	(	deflate_state *	s,
		int	flush
	)

Definition at line 1571 of file deflate.cc.

 {
     IPos hash_head;       /* head of the hash chain */
     int bflush;           /* set if current block must be flushed */
 
     for (;;) {
         /* Make sure that we always have enough lookahead, except
          * at the end of the input file. We need MAX_MATCH bytes
          * for the next match, plus MIN_MATCH bytes to insert the
          * string following the next match.
          */
         if (s->lookahead < MIN_LOOKAHEAD) {
             fill_window(s);
             if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
                 return need_more;
             }
             if (s->lookahead == 0) break; /* flush the current block */
         }
 
         /* Insert the string window[strstart .. strstart+2] in the
          * dictionary, and set hash_head to the head of the hash chain:
          */
         hash_head = NIL;
         if (s->lookahead >= MIN_MATCH) {
             INSERT_STRING(s, s->strstart, hash_head);
         }
 
         /* Find the longest match, discarding those <= prev_length.
          * At this point we have always match_length < MIN_MATCH
          */
         if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) {
             /* To simplify the code, we prevent matches with the string
              * of window index 0 (in particular we have to avoid a match
              * of the string with itself at the start of the input file).
              */
             s->match_length = longest_match (s, hash_head);
             /* longest_match() sets match_start */
         }
         if (s->match_length >= MIN_MATCH) {
             check_match(s, s->strstart, s->match_start, s->match_length);
 
             _tr_tally_dist(s, s->strstart - s->match_start,
                            s->match_length - MIN_MATCH, bflush);
 
             s->lookahead -= s->match_length;
 
             /* Insert new strings in the hash table only if the match length
              * is not too large. This saves time but degrades compression.
              */
 #ifndef FASTEST
             if (s->match_length <= s->max_insert_length &&
                 s->lookahead >= MIN_MATCH) {
                 s->match_length--; /* string at strstart already in table */
                 do {
                     s->strstart++;
                     INSERT_STRING(s, s->strstart, hash_head);
                     /* strstart never exceeds WSIZE-MAX_MATCH, so there are
                      * always MIN_MATCH bytes ahead.
                      */
                 } while (--s->match_length != 0);
                 s->strstart++;
             } else
 #endif
             {
                 s->strstart += s->match_length;
                 s->match_length = 0;
                 s->ins_h = s->window[s->strstart];
                 UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);
 #if MIN_MATCH != 3
                 Call UPDATE_HASH() MIN_MATCH-3 more times
 #endif
                 /* If lookahead < MIN_MATCH, ins_h is garbage, but it does not
                  * matter since it will be recomputed at next deflate call.
                  */
             }
         } else {
             /* No match, output a literal byte */
             Tracevv((stderr,"%c", s->window[s->strstart]));
             _tr_tally_lit (s, s->window[s->strstart], bflush);
             s->lookahead--;
             s->strstart++;
         }
         if (bflush) FLUSH_BLOCK(s, 0);
     }
     s->insert = s->strstart < MIN_MATCH-1 ? s->strstart : MIN_MATCH-1;
     if (flush == Z_FINISH) {
         FLUSH_BLOCK(s, 1);
         return finish_done;
     }
     if (s->last_lit)
         FLUSH_BLOCK(s, 0);
     return block_done;
 }

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local block_state deflate_huff	(	deflate_state *	s,
		int	flush
	)

Definition at line 1871 of file deflate.cc.

 {
     int bflush;             /* set if current block must be flushed */
 
     for (;;) {
         /* Make sure that we have a literal to write. */
         if (s->lookahead == 0) {
             fill_window(s);
             if (s->lookahead == 0) {
                 if (flush == Z_NO_FLUSH)
                     return need_more;
                 break;      /* flush the current block */
             }
         }
 
         /* Output a literal byte */
         s->match_length = 0;
         Tracevv((stderr,"%c", s->window[s->strstart]));
         _tr_tally_lit (s, s->window[s->strstart], bflush);
         s->lookahead--;
         s->strstart++;
         if (bflush) FLUSH_BLOCK(s, 0);
     }
     s->insert = 0;
     if (flush == Z_FINISH) {
         FLUSH_BLOCK(s, 1);
         return finish_done;
     }
     if (s->last_lit)
         FLUSH_BLOCK(s, 0);
     return block_done;
 }

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local block_state deflate_rle	(	deflate_state *	s,
		int	flush
	)

Definition at line 1800 of file deflate.cc.

 {
     int bflush;             /* set if current block must be flushed */
     uInt prev;              /* byte at distance one to match */
     Bytef *scan, *strend;   /* scan goes up to strend for length of run */
 
     for (;;) {
         /* Make sure that we always have enough lookahead, except
          * at the end of the input file. We need MAX_MATCH bytes
          * for the longest run, plus one for the unrolled loop.
          */
         if (s->lookahead <= MAX_MATCH) {
             fill_window(s);
             if (s->lookahead <= MAX_MATCH && flush == Z_NO_FLUSH) {
                 return need_more;
             }
             if (s->lookahead == 0) break; /* flush the current block */
         }
 
         /* See how many times the previous byte repeats */
         s->match_length = 0;
         if (s->lookahead >= MIN_MATCH && s->strstart > 0) {
             scan = s->window + s->strstart - 1;
             prev = *scan;
             if (prev == *++scan && prev == *++scan && prev == *++scan) {
                 strend = s->window + s->strstart + MAX_MATCH;
                 do {
                 } while (prev == *++scan && prev == *++scan &&
                          prev == *++scan && prev == *++scan &&
                          prev == *++scan && prev == *++scan &&
                          prev == *++scan && prev == *++scan &&
                          scan < strend);
                 s->match_length = MAX_MATCH - (int)(strend - scan);
                 if (s->match_length > s->lookahead)
                     s->match_length = s->lookahead;
             }
             Assert(scan <= s->window+(uInt)(s->window_size-1), "wild scan");
         }
 
         /* Emit match if have run of MIN_MATCH or longer, else emit literal */
         if (s->match_length >= MIN_MATCH) {
             check_match(s, s->strstart, s->strstart - 1, s->match_length);
 
             _tr_tally_dist(s, 1, s->match_length - MIN_MATCH, bflush);
 
             s->lookahead -= s->match_length;
             s->strstart += s->match_length;
             s->match_length = 0;
         } else {
             /* No match, output a literal byte */
             Tracevv((stderr,"%c", s->window[s->strstart]));
             _tr_tally_lit (s, s->window[s->strstart], bflush);
             s->lookahead--;
             s->strstart++;
         }
         if (bflush) FLUSH_BLOCK(s, 0);
     }
     s->insert = 0;
     if (flush == Z_FINISH) {
         FLUSH_BLOCK(s, 1);
         return finish_done;
     }
     if (s->last_lit)
         FLUSH_BLOCK(s, 0);
     return block_done;
 }

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local block_state deflate_slow	(	deflate_state *	s,
		int	flush
	)

Definition at line 1671 of file deflate.cc.

 {
     IPos hash_head;          /* head of hash chain */
     int bflush;              /* set if current block must be flushed */
 
     /* Process the input block. */
     for (;;) {
         /* Make sure that we always have enough lookahead, except
          * at the end of the input file. We need MAX_MATCH bytes
          * for the next match, plus MIN_MATCH bytes to insert the
          * string following the next match.
          */
         if (s->lookahead < MIN_LOOKAHEAD) {
             fill_window(s);
             if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
                 return need_more;
             }
             if (s->lookahead == 0) break; /* flush the current block */
         }
 
         /* Insert the string window[strstart .. strstart+2] in the
          * dictionary, and set hash_head to the head of the hash chain:
          */
         hash_head = NIL;
         if (s->lookahead >= MIN_MATCH) {
             INSERT_STRING(s, s->strstart, hash_head);
         }
 
         /* Find the longest match, discarding those <= prev_length.
          */
         s->prev_length = s->match_length, s->prev_match = s->match_start;
         s->match_length = MIN_MATCH-1;
 
         if (hash_head != NIL && s->prev_length < s->max_lazy_match &&
             s->strstart - hash_head <= MAX_DIST(s)) {
             /* To simplify the code, we prevent matches with the string
              * of window index 0 (in particular we have to avoid a match
              * of the string with itself at the start of the input file).
              */
             s->match_length = longest_match (s, hash_head);
             /* longest_match() sets match_start */
 
             if (s->match_length <= 5 && (s->strategy == Z_FILTERED
 #if TOO_FAR <= 32767
                 || (s->match_length == MIN_MATCH &&
                     s->strstart - s->match_start > TOO_FAR)
 #endif
                 )) {
 
                 /* If prev_match is also MIN_MATCH, match_start is garbage
                  * but we will ignore the current match anyway.
                  */
                 s->match_length = MIN_MATCH-1;
             }
         }
         /* If there was a match at the previous step and the current
          * match is not better, output the previous match:
          */
         if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) {
             uInt max_insert = s->strstart + s->lookahead - MIN_MATCH;
             /* Do not insert strings in hash table beyond this. */
 
             check_match(s, s->strstart-1, s->prev_match, s->prev_length);
 
             _tr_tally_dist(s, s->strstart -1 - s->prev_match,
                            s->prev_length - MIN_MATCH, bflush);
 
             /* Insert in hash table all strings up to the end of the match.
              * strstart-1 and strstart are already inserted. If there is not
              * enough lookahead, the last two strings are not inserted in
              * the hash table.
              */
             s->lookahead -= s->prev_length-1;
             s->prev_length -= 2;
             do {
                 if (++s->strstart <= max_insert) {
                     INSERT_STRING(s, s->strstart, hash_head);
                 }
             } while (--s->prev_length != 0);
             s->match_available = 0;
             s->match_length = MIN_MATCH-1;
             s->strstart++;
 
             if (bflush) FLUSH_BLOCK(s, 0);
 
         } else if (s->match_available) {
             /* If there was no match at the previous position, output a
              * single literal. If there was a match but the current match
              * is longer, truncate the previous match to a single literal.
              */
             Tracevv((stderr,"%c", s->window[s->strstart-1]));
             _tr_tally_lit(s, s->window[s->strstart-1], bflush);
             if (bflush) {
                 FLUSH_BLOCK_ONLY(s, 0);
             }
             s->strstart++;
             s->lookahead--;
             if (s->strm->avail_out == 0) return need_more;
         } else {
             /* There is no previous match to compare with, wait for
              * the next step to decide.
              */
             s->match_available = 1;
             s->strstart++;
             s->lookahead--;
         }
     }
     Assert (flush != Z_NO_FLUSH, "no flush?");
     if (s->match_available) {
         Tracevv((stderr,"%c", s->window[s->strstart-1]));
         _tr_tally_lit(s, s->window[s->strstart-1], bflush);
         s->match_available = 0;
     }
     s->insert = s->strstart < MIN_MATCH-1 ? s->strstart : MIN_MATCH-1;
     if (flush == Z_FINISH) {
         FLUSH_BLOCK(s, 1);
         return finish_done;
     }
     if (s->last_lit)
         FLUSH_BLOCK(s, 0);
     return block_done;
 }

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local block_state deflate_stored	(	deflate_state *	s,
		int	flush
	)

Definition at line 1509 of file deflate.cc.

 {
     /* Stored blocks are limited to 0xffff bytes, pending_buf is limited
      * to pending_buf_size, and each stored block has a 5 byte header:
      */
     ulg max_block_size = 0xffff;
     ulg max_start;
 
     if (max_block_size > s->pending_buf_size - 5) {
         max_block_size = s->pending_buf_size - 5;
     }
 
     /* Copy as much as possible from input to output: */
     for (;;) {
         /* Fill the window as much as possible: */
         if (s->lookahead <= 1) {
 
             Assert(s->strstart < s->w_size+MAX_DIST(s) ||
                    s->block_start >= (long)s->w_size, "slide too late");
 
             fill_window(s);
             if (s->lookahead == 0 && flush == Z_NO_FLUSH) return need_more;
 
             if (s->lookahead == 0) break; /* flush the current block */
         }
         Assert(s->block_start >= 0L, "block gone");
 
         s->strstart += s->lookahead;
         s->lookahead = 0;
 
         /* Emit a stored block if pending_buf will be full: */
         max_start = s->block_start + max_block_size;
         if (s->strstart == 0 || (ulg)s->strstart >= max_start) {
             /* strstart == 0 is possible when wraparound on 16-bit machine */
             s->lookahead = (uInt)(s->strstart - max_start);
             s->strstart = (uInt)max_start;
             FLUSH_BLOCK(s, 0);
         }
         /* Flush if we may have to slide, otherwise block_start may become
          * negative and the data will be gone:
          */
         if (s->strstart - (uInt)s->block_start >= MAX_DIST(s)) {
             FLUSH_BLOCK(s, 0);
         }
     }
     s->insert = 0;
     if (flush == Z_FINISH) {
         FLUSH_BLOCK(s, 1);
         return finish_done;
     }
     if ((long)s->strstart > s->block_start)
         FLUSH_BLOCK(s, 0);
     return block_done;
 }

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uLong ZEXPORT deflateBound	(	z_streamp	strm,
		uLong	sourceLen
	)

Definition at line 533 of file deflate.cc.

 {
     deflate_state *s;
     uLong complen, wraplen;
     Bytef *str;
 
     /* conservative upper bound for compressed data */
     complen = sourceLen +
               ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 5;
 
     /* if can't get parameters, return conservative bound plus zlib wrapper */
     if (strm == Z_NULL || strm->state == Z_NULL)
         return complen + 6;
 
     /* compute wrapper length */
     s = strm->state;
     switch (s->wrap) {
     case 0:                                 /* raw deflate */
         wraplen = 0;
         break;
     case 1:                                 /* zlib wrapper */
         wraplen = 6 + (s->strstart ? 4 : 0);
         break;
     case 2:                                 /* gzip wrapper */
         wraplen = 18;
         if (s->gzhead != Z_NULL) {          /* user-supplied gzip header */
             if (s->gzhead->extra != Z_NULL)
                 wraplen += 2 + s->gzhead->extra_len;
             str = s->gzhead->name;
             if (str != Z_NULL)
                 do {
                     wraplen++;
                 } while (*str++);
             str = s->gzhead->comment;
             if (str != Z_NULL)
                 do {
                     wraplen++;
                 } while (*str++);
             if (s->gzhead->hcrc)
                 wraplen += 2;
         }
         break;
     default:                                /* for compiler happiness */
         wraplen = 6;
     }
 
     /* if not default parameters, return conservative bound */
     if (s->w_bits != 15 || s->hash_bits != 8 + 7)
         return complen + wraplen;
 
     /* default settings: return tight bound for that case */
     return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) +
            (sourceLen >> 25) + 13 - 6 + wraplen;
 }

int ZEXPORT deflateCopy	(	z_streamp	dest,
		z_streamp	source
	)

Definition at line 973 of file deflate.cc.

 {
 #ifdef MAXSEG_64K
     return Z_STREAM_ERROR;
 #else
     deflate_state *ds;
     deflate_state *ss;
     ushf *overlay;
 
 
     if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL) {
         return Z_STREAM_ERROR;
     }
 
     ss = source->state;
 
     zmemcpy((voidpf)dest, (voidpf)source, sizeof(z_stream));
 
     ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state));
     if (ds == Z_NULL) return Z_MEM_ERROR;
     dest->state = (struct internal_state FAR *) ds;
     zmemcpy((voidpf)ds, (voidpf)ss, sizeof(deflate_state));
     ds->strm = dest;
 
     ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte));
     ds->prev   = (Posf *)  ZALLOC(dest, ds->w_size, sizeof(Pos));
     ds->head   = (Posf *)  ZALLOC(dest, ds->hash_size, sizeof(Pos));
     overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2);
     ds->pending_buf = (uchf *) overlay;
 
     if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL ||
         ds->pending_buf == Z_NULL) {
         deflateEnd (dest);
         return Z_MEM_ERROR;
     }
     /* following zmemcpy do not work for 16-bit MSDOS */
     zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte));
     zmemcpy((voidpf)ds->prev, (voidpf)ss->prev, ds->w_size * sizeof(Pos));
     zmemcpy((voidpf)ds->head, (voidpf)ss->head, ds->hash_size * sizeof(Pos));
     zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size);
 
     ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf);
     ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush);
     ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize;
 
     ds->l_desc.dyn_tree = ds->dyn_ltree;
     ds->d_desc.dyn_tree = ds->dyn_dtree;
     ds->bl_desc.dyn_tree = ds->bl_tree;
 
     return Z_OK;
 #endif /* MAXSEG_64K */
 }

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int ZEXPORT deflateEnd ( z_streamp strm )

Definition at line 939 of file deflate.cc.

 {
     int status;
 
     if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
 
     status = strm->state->status;
     if (status != INIT_STATE &&
         status != EXTRA_STATE &&
         status != NAME_STATE &&
         status != COMMENT_STATE &&
         status != HCRC_STATE &&
         status != BUSY_STATE &&
         status != FINISH_STATE) {
       return Z_STREAM_ERROR;
     }
 
     /* Deallocate in reverse order of allocations: */
     TRY_FREE(strm, strm->state->pending_buf);
     TRY_FREE(strm, strm->state->head);
     TRY_FREE(strm, strm->state->prev);
     TRY_FREE(strm, strm->state->window);
 
     ZFREE(strm, strm->state);
     strm->state = Z_NULL;
 
     return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK;
 }

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int ZEXPORT deflateInit2_	(	z_streamp	strm,
		int	level,
		int	method,
		int	windowBits,
		int	memLevel,
		int	strategy,
		const char *	version,
		int	stream_size
	)

Definition at line 209 of file deflate.cc.

 {
     deflate_state *s;
     int wrap = 1;
     static const char my_version[] = ZLIB_VERSION;
 
     ushf *overlay;
     /* We overlay pending_buf and d_buf+l_buf. This works since the average
      * output size for (length,distance) codes is <= 24 bits.
      */
 
     if (version == Z_NULL || version[0] != my_version[0] ||
         stream_size != sizeof(z_stream)) {
         return Z_VERSION_ERROR;
     }
     if (strm == Z_NULL) return Z_STREAM_ERROR;
 
     strm->msg = Z_NULL;
     if (strm->zalloc == (alloc_func)0) {
 #ifdef Z_SOLO
         return Z_STREAM_ERROR;
 #else
         strm->zalloc = zcalloc;
         strm->opaque = (voidpf)0;
 #endif
     }
     if (strm->zfree == (free_func)0)
 #ifdef Z_SOLO
         return Z_STREAM_ERROR;
 #else
         strm->zfree = zcfree;
 #endif
 
 #ifdef FASTEST
     if (level != 0) level = 1;
 #else
     if (level == Z_DEFAULT_COMPRESSION) level = 6;
 #endif
 
     if (windowBits < 0) { /* suppress zlib wrapper */
         wrap = 0;
         windowBits = -windowBits;
     }
 #ifdef GZIP
     else if (windowBits > 15) {
         wrap = 2;       /* write gzip wrapper instead */
         windowBits -= 16;
     }
 #endif
     if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED ||
         windowBits < 8 || windowBits > 15 || level < 0 || level > 9 ||
         strategy < 0 || strategy > Z_FIXED) {
         return Z_STREAM_ERROR;
     }
     if (windowBits == 8) windowBits = 9;  /* until 256-byte window bug fixed */
     s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state));
     if (s == Z_NULL) return Z_MEM_ERROR;
     strm->state = (struct internal_state FAR *)s;
     s->strm = strm;
 
     s->wrap = wrap;
     s->gzhead = Z_NULL;
     s->w_bits = windowBits;
     s->w_size = 1 << s->w_bits;
     s->w_mask = s->w_size - 1;
 
     s->hash_bits = memLevel + 7;
     s->hash_size = 1 << s->hash_bits;
     s->hash_mask = s->hash_size - 1;
     s->hash_shift =  ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH);
 
     s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte));
     s->prev   = (Posf *)  ZALLOC(strm, s->w_size, sizeof(Pos));
     s->head   = (Posf *)  ZALLOC(strm, s->hash_size, sizeof(Pos));
 
     s->high_water = 0;      /* nothing written to s->window yet */
 
     s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */
 
     overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2);
     s->pending_buf = (uchf *) overlay;
     s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L);
 
     if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL ||
         s->pending_buf == Z_NULL) {
         s->status = FINISH_STATE;
         strm->msg = ERR_MSG(Z_MEM_ERROR);
         deflateEnd (strm);
         return Z_MEM_ERROR;
     }
     s->d_buf = overlay + s->lit_bufsize/sizeof(ush);
     s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize;
 
     s->level = level;
     s->strategy = strategy;
     s->method = (Byte)method;
 
     return deflateReset(strm);
 }

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int ZEXPORT deflateInit_	(	z_streamp	strm,
		int	level,
		const char *	version,
		int	stream_size
	)

Definition at line 201 of file deflate.cc.

 {
     return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL,
                          Z_DEFAULT_STRATEGY, version, stream_size);
     /* To do: ignore strm->next_in if we use it as window */
 }

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int ZEXPORT deflateParams	(	z_streamp	strm,
		int	level,
		int	strategy
	)

Definition at line 465 of file deflate.cc.

 {
     deflate_state *s;
     compress_func func;
     int err = Z_OK;
 
     if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
     s = strm->state;
 
 #ifdef FASTEST
     if (level != 0) level = 1;
 #else
     if (level == Z_DEFAULT_COMPRESSION) level = 6;
 #endif
     if (level < 0 || level > 9 || strategy < 0 || strategy > Z_FIXED) {
         return Z_STREAM_ERROR;
     }
     func = configuration_table[s->level].func;
 
     if ((strategy != s->strategy || func != configuration_table[level].func) &&
         strm->total_in != 0) {
         /* Flush the last buffer: */
         err = deflate(strm, Z_BLOCK);
         if (err == Z_BUF_ERROR && s->pending == 0)
             err = Z_OK;
     }
     if (s->level != level) {
         s->level = level;
         s->max_lazy_match   = configuration_table[level].max_lazy;
         s->good_match       = configuration_table[level].good_length;
         s->nice_match       = configuration_table[level].nice_length;
         s->max_chain_length = configuration_table[level].max_chain;
     }
     s->strategy = strategy;
     return err;
 }

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int ZEXPORT deflatePending	(	z_streamp	strm,
		unsigned *	pending,
		int *	bits
	)

Definition at line 431 of file deflate.cc.

 {
     if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
     if (pending != Z_NULL)
         *pending = strm->state->pending;
     if (bits != Z_NULL)
         *bits = strm->state->bi_valid;
     return Z_OK;
 }

int ZEXPORT deflatePrime	(	z_streamp	strm,
		int	bits,
		int	value
	)

Definition at line 442 of file deflate.cc.

 {
     deflate_state *s;
     int put;
 
     if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
     s = strm->state;
     if ((Bytef *)(s->d_buf) < s->pending_out + ((Buf_size + 7) >> 3))
         return Z_BUF_ERROR;
     do {
         put = Buf_size - s->bi_valid;
         if (put > bits)
             put = bits;
         s->bi_buf |= (ush)((value & ((1 << put) - 1)) << s->bi_valid);
         s->bi_valid += put;
         _tr_flush_bits(s);
         value >>= put;
         bits -= put;
     } while (bits);
     return Z_OK;
 }

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int ZEXPORT deflateReset ( z_streamp strm )

Definition at line 411 of file deflate.cc.

 {
     int ret;
 
     ret = deflateResetKeep(strm);
     if (ret == Z_OK)
         lm_init(strm->state);
     return ret;
 }

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int ZEXPORT deflateResetKeep ( z_streamp strm )

Definition at line 377 of file deflate.cc.

 {
     deflate_state *s;
 
     if (strm == Z_NULL || strm->state == Z_NULL ||
         strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0) {
         return Z_STREAM_ERROR;
     }
 
     strm->total_in = strm->total_out = 0;
     strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */
     strm->data_type = Z_UNKNOWN;
 
     s = (deflate_state *)strm->state;
     s->pending = 0;
     s->pending_out = s->pending_buf;
 
     if (s->wrap < 0) {
         s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */
     }
     s->status = s->wrap ? INIT_STATE : BUSY_STATE;
     strm->adler =
 #ifdef GZIP
         s->wrap == 2 ? crc32(0L, Z_NULL, 0) :
 #endif
         adler32(0L, Z_NULL, 0);
     s->last_flush = Z_NO_FLUSH;
 
     _tr_init(s);
 
     return Z_OK;
 }

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int ZEXPORT deflateSetDictionary	(	z_streamp	strm,
		const Bytef *	dictionary,
		uInt	dictLength
	)

Definition at line 311 of file deflate.cc.

 {
     deflate_state *s;
     uInt str, n;
     int wrap;
     unsigned avail;
     z_const unsigned char *next;
 
     if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL)
         return Z_STREAM_ERROR;
     s = strm->state;
     wrap = s->wrap;
     if (wrap == 2 || (wrap == 1 && s->status != INIT_STATE) || s->lookahead)
         return Z_STREAM_ERROR;
 
     /* when using zlib wrappers, compute Adler-32 for provided dictionary */
     if (wrap == 1)
         strm->adler = adler32(strm->adler, dictionary, dictLength);
     s->wrap = 0;                    /* avoid computing Adler-32 in read_buf */
 
     /* if dictionary would fill window, just replace the history */
     if (dictLength >= s->w_size) {
         if (wrap == 0) {            /* already empty otherwise */
             CLEAR_HASH(s);
             s->strstart = 0;
             s->block_start = 0L;
             s->insert = 0;
         }
         dictionary += dictLength - s->w_size;  /* use the tail */
         dictLength = s->w_size;
     }
 
     /* insert dictionary into window and hash */
     avail = strm->avail_in;
     next = strm->next_in;
     strm->avail_in = dictLength;
     strm->next_in = (z_const Bytef *)dictionary;
     fill_window(s);
     while (s->lookahead >= MIN_MATCH) {
         str = s->strstart;
         n = s->lookahead - (MIN_MATCH-1);
         do {
             UPDATE_HASH(s, s->ins_h, s->window[str + MIN_MATCH-1]);
 #ifndef FASTEST
             s->prev[str & s->w_mask] = s->head[s->ins_h];
 #endif
             s->head[s->ins_h] = (Pos)str;
             str++;
         } while (--n);
         s->strstart = str;
         s->lookahead = MIN_MATCH-1;
         fill_window(s);
     }
     s->strstart += s->lookahead;
     s->block_start = (long)s->strstart;
     s->insert = s->lookahead;
     s->lookahead = 0;
     s->match_length = s->prev_length = MIN_MATCH-1;
     s->match_available = 0;
     strm->next_in = next;
     strm->avail_in = avail;
     s->wrap = wrap;
     return Z_OK;
 }

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int ZEXPORT deflateSetHeader	(	z_streamp	strm,
		gz_headerp	head
	)

Definition at line 422 of file deflate.cc.

 {
     if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
     if (strm->state->wrap != 2) return Z_STREAM_ERROR;
     strm->state->gzhead = head;
     return Z_OK;
 }

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

Definition at line 503 of file deflate.cc.

 {
     deflate_state *s;
 
     if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
     s = strm->state;
     s->good_match = good_length;
     s->max_lazy_match = max_lazy;
     s->nice_match = nice_length;
     s->max_chain_length = max_chain;
     return Z_OK;
 }

local void fill_window ( deflate_state * s )

Definition at line 1336 of file deflate.cc.

 {
     unsigned n, m;
     Posf *p;
     unsigned more;    /* Amount of free space at the end of the window. */
     uInt wsize = s->w_size;
 
     Assert(s->lookahead < MIN_LOOKAHEAD, "already enough lookahead");
 
     do {
         more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart);
 
         /* Deal with !@#$% 64K limit: */
         if (sizeof(int) <= 2) {
             if (more == 0 && s->strstart == 0 && s->lookahead == 0) {
                 more = wsize;
 
             } else if (more == (unsigned)(-1)) {
                 /* Very unlikely, but possible on 16 bit machine if
                  * strstart == 0 && lookahead == 1 (input done a byte at time)
                  */
                 more--;
             }
         }
 
         /* If the window is almost full and there is insufficient lookahead,
          * move the upper half to the lower one to make room in the upper half.
          */
         if (s->strstart >= wsize+MAX_DIST(s)) {
 
             zmemcpy(s->window, s->window+wsize, (unsigned)wsize);
             s->match_start -= wsize;
             s->strstart    -= wsize; /* we now have strstart >= MAX_DIST */
             s->block_start -= (long) wsize;
 
             /* Slide the hash table (could be avoided with 32 bit values
                at the expense of memory usage). We slide even when level == 0
                to keep the hash table consistent if we switch back to level > 0
                later. (Using level 0 permanently is not an optimal usage of
                zlib, so we don't care about this pathological case.)
              */
             n = s->hash_size;
             p = &s->head[n];
             do {
                 m = *--p;
                 *p = (Pos)(m >= wsize ? m-wsize : NIL);
             } while (--n);
 
             n = wsize;
 #ifndef FASTEST
             p = &s->prev[n];
             do {
                 m = *--p;
                 *p = (Pos)(m >= wsize ? m-wsize : NIL);
                 /* If n is not on any hash chain, prev[n] is garbage but
                  * its value will never be used.
                  */
             } while (--n);
 #endif
             more += wsize;
         }
         if (s->strm->avail_in == 0) break;
 
         /* If there was no sliding:
          *    strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 &&
          *    more == window_size - lookahead - strstart
          * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1)
          * => more >= window_size - 2*WSIZE + 2
          * In the BIG_MEM or MMAP case (not yet supported),
          *   window_size == input_size + MIN_LOOKAHEAD  &&
          *   strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD.
          * Otherwise, window_size == 2*WSIZE so more >= 2.
          * If there was sliding, more >= WSIZE. So in all cases, more >= 2.
          */
         Assert(more >= 2, "more < 2");
 
         n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more);
         s->lookahead += n;
 
         /* Initialize the hash value now that we have some input: */
         if (s->lookahead + s->insert >= MIN_MATCH) {
             uInt str = s->strstart - s->insert;
             s->ins_h = s->window[str];
             UPDATE_HASH(s, s->ins_h, s->window[str + 1]);
 #if MIN_MATCH != 3
             Call UPDATE_HASH() MIN_MATCH-3 more times
 #endif
             while (s->insert) {
                 UPDATE_HASH(s, s->ins_h, s->window[str + MIN_MATCH-1]);
 #ifndef FASTEST
                 s->prev[str & s->w_mask] = s->head[s->ins_h];
 #endif
                 s->head[s->ins_h] = (Pos)str;
                 str++;
                 s->insert--;
                 if (s->lookahead + s->insert < MIN_MATCH)
                     break;
             }
         }
         /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage,
          * but this is not important since only literal bytes will be emitted.
          */
 
     } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0);
 
     /* If the WIN_INIT bytes after the end of the current data have never been
      * written, then zero those bytes in order to avoid memory check reports of
      * the use of uninitialized (or uninitialised as Julian writes) bytes by
      * the longest match routines.  Update the high water mark for the next
      * time through here.  WIN_INIT is set to MAX_MATCH since the longest match
      * routines allow scanning to strstart + MAX_MATCH, ignoring lookahead.
      */
     if (s->high_water < s->window_size) {
         ulg curr = s->strstart + (ulg)(s->lookahead);
         ulg init;
 
         if (s->high_water < curr) {
             /* Previous high water mark below current data -- zero WIN_INIT
              * bytes or up to end of window, whichever is less.
              */
             init = s->window_size - curr;
             if (init > WIN_INIT)
                 init = WIN_INIT;
             zmemzero(s->window + curr, (unsigned)init);
             s->high_water = curr + init;
         }
         else if (s->high_water < (ulg)curr + WIN_INIT) {
             /* High water mark at or above current data, but below current data
              * plus WIN_INIT -- zero out to current data plus WIN_INIT, or up
              * to end of window, whichever is less.
              */
             init = (ulg)curr + WIN_INIT - s->high_water;
             if (init > s->window_size - s->high_water)
                 init = s->window_size - s->high_water;
             zmemzero(s->window + s->high_water, (unsigned)init);
             s->high_water += init;
         }
     }
 
     Assert((ulg)s->strstart <= s->window_size - MIN_LOOKAHEAD,
            "not enough room for search");
 }

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local void flush_pending ( z_streamp strm )

Definition at line 605 of file deflate.cc.

 {
     unsigned len;
     deflate_state *s = strm->state;
 
     _tr_flush_bits(s);
     len = s->pending;
     if (len > strm->avail_out) len = strm->avail_out;
     if (len == 0) return;
 
     zmemcpy(strm->next_out, s->pending_out, len);
     strm->next_out  += len;
     s->pending_out  += len;
     strm->total_out += len;
     strm->avail_out  -= len;
     s->pending -= len;
     if (s->pending == 0) {
         s->pending_out = s->pending_buf;
     }
 }

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local void lm_init ( deflate_state * s )

Definition at line 1060 of file deflate.cc.

 {
     s->window_size = (ulg)2L*s->w_size;
 
     CLEAR_HASH(s);
 
     /* Set the default configuration parameters:
      */
     s->max_lazy_match   = configuration_table[s->level].max_lazy;
     s->good_match       = configuration_table[s->level].good_length;
     s->nice_match       = configuration_table[s->level].nice_length;
     s->max_chain_length = configuration_table[s->level].max_chain;
 
     s->strstart = 0;
     s->block_start = 0L;
     s->lookahead = 0;
     s->insert = 0;
     s->match_length = s->prev_length = MIN_MATCH-1;
     s->match_available = 0;
     s->ins_h = 0;
 #ifndef FASTEST
 #ifdef ASMV
     match_init(); /* initialize the asm code */
 #endif
 #endif
 }

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local uInt longest_match	(	deflate_state *	s,
		IPos	cur_match
	)

Definition at line 1101 of file deflate.cc.

 {
     unsigned chain_length = s->max_chain_length;/* max hash chain length */
     Bytef *scan = s->window + s->strstart; /* current string */
     Bytef *match;                       /* matched string */
     int len;                           /* length of current match */
     int best_len = s->prev_length;              /* best match length so far */
     int nice_match = s->nice_match;             /* stop if match long enough */
     IPos limit = s->strstart > (IPos)MAX_DIST(s) ?
         s->strstart - (IPos)MAX_DIST(s) : NIL;
     /* Stop when cur_match becomes <= limit. To simplify the code,
      * we prevent matches with the string of window index 0.
      */
     Posf *prev = s->prev;
     uInt wmask = s->w_mask;
 
 #ifdef UNALIGNED_OK
     /* Compare two bytes at a time. Note: this is not always beneficial.
      * Try with and without -DUNALIGNED_OK to check.
      */
     Bytef *strend = s->window + s->strstart + MAX_MATCH - 1;
     ush scan_start = *(ushf*)scan;
     ush scan_end   = *(ushf*)(scan+best_len-1);
 #else
     Bytef *strend = s->window + s->strstart + MAX_MATCH;
     Byte scan_end1  = scan[best_len-1];
     Byte scan_end   = scan[best_len];
 #endif
 
     /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
      * It is easy to get rid of this optimization if necessary.
      */
     Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
 
     /* Do not waste too much time if we already have a good match: */
     if (s->prev_length >= s->good_match) {
         chain_length >>= 2;
     }
     /* Do not look for matches beyond the end of the input. This is necessary
      * to make deflate deterministic.
      */
     if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead;
 
     Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
 
     do {
         Assert(cur_match < s->strstart, "no future");
         match = s->window + cur_match;
 
         /* Skip to next match if the match length cannot increase
          * or if the match length is less than 2.  Note that the checks below
          * for insufficient lookahead only occur occasionally for performance
          * reasons.  Therefore uninitialized memory will be accessed, and
          * conditional jumps will be made that depend on those values.
          * However the length of the match is limited to the lookahead, so
          * the output of deflate is not affected by the uninitialized values.
          */
 #if (defined(UNALIGNED_OK) && MAX_MATCH == 258)
         /* This code assumes sizeof(unsigned short) == 2. Do not use
          * UNALIGNED_OK if your compiler uses a different size.
          */
         if (*(ushf*)(match+best_len-1) != scan_end ||
             *(ushf*)match != scan_start) continue;
 
         /* It is not necessary to compare scan[2] and match[2] since they are
          * always equal when the other bytes match, given that the hash keys
          * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at
          * strstart+3, +5, ... up to strstart+257. We check for insufficient
          * lookahead only every 4th comparison; the 128th check will be made
          * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is
          * necessary to put more guard bytes at the end of the window, or
          * to check more often for insufficient lookahead.
          */
         Assert(scan[2] == match[2], "scan[2]?");
         scan++, match++;
         do {
         } while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
                  *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
                  *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
                  *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
                  scan < strend);
         /* The funny "do {}" generates better code on most compilers */
 
         /* Here, scan <= window+strstart+257 */
         Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
         if (*scan == *match) scan++;
 
         len = (MAX_MATCH - 1) - (int)(strend-scan);
         scan = strend - (MAX_MATCH-1);
 
 #else /* UNALIGNED_OK */
 
         if (match[best_len]   != scan_end  ||
             match[best_len-1] != scan_end1 ||
             *match            != *scan     ||
             *++match          != scan[1])      continue;
 
         /* The check at best_len-1 can be removed because it will be made
          * again later. (This heuristic is not always a win.)
          * It is not necessary to compare scan[2] and match[2] since they
          * are always equal when the other bytes match, given that
          * the hash keys are equal and that HASH_BITS >= 8.
          */
         scan += 2, match++;
         Assert(*scan == *match, "match[2]?");
 
         /* We check for insufficient lookahead only every 8th comparison;
          * the 256th check will be made at strstart+258.
          */
         do {
         } while (*++scan == *++match && *++scan == *++match &&
                  *++scan == *++match && *++scan == *++match &&
                  *++scan == *++match && *++scan == *++match &&
                  *++scan == *++match && *++scan == *++match &&
                  scan < strend);
 
         Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
 
         len = MAX_MATCH - (int)(strend - scan);
         scan = strend - MAX_MATCH;
 
 #endif /* UNALIGNED_OK */
 
         if (len > best_len) {
             s->match_start = cur_match;
             best_len = len;
             if (len >= nice_match) break;
 #ifdef UNALIGNED_OK
             scan_end = *(ushf*)(scan+best_len-1);
 #else
             scan_end1  = scan[best_len-1];
             scan_end   = scan[best_len];
 #endif
         }
     } while ((cur_match = prev[cur_match & wmask]) > limit
              && --chain_length != 0);
 
     if ((uInt)best_len <= s->lookahead) return (uInt)best_len;
     return s->lookahead;
 }

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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) )

local void putShortMSB	(	deflate_state *	s,
		uInt	b
	)

Definition at line 593 of file deflate.cc.

 {
     put_byte(s, (Byte)(b >> 8));
     put_byte(s, (Byte)(b & 0xff));
 }

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

Definition at line 1033 of file deflate.cc.

 {
     unsigned len = strm->avail_in;
 
     if (len > size) len = size;
     if (len == 0) return 0;
 
     strm->avail_in  -= len;
 
     zmemcpy(buf, strm->next_in, len);
     if (strm->state->wrap == 1) {
         strm->adler = adler32(strm->adler, buf, len);
     }
 #ifdef GZIP
     else if (strm->state->wrap == 2) {
         strm->adler = crc32(strm->adler, buf, len);
     }
 #endif
     strm->next_in  += len;
     strm->total_in += len;
 
     return (int)len;
 }

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Variable Documentation

local const config configuration_table[10]

Initial value:

= {
 {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}}

Definition at line 131 of file deflate.cc.

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