zlib 1.1.4

z_stream_s

.

• const char * zlibVersion (void);
• int deflateInit (z_streamp strm, int level);
• int deflate (z_streamp strm, int flush);
• int deflateEnd (z_streamp strm);
• int inflateInit (z_streamp strm);
• int inflate (z_streamp strm, int flush);
• int inflateEnd (z_streamp strm);

const char * zlibVersion (void);

zlibVersion ZLIB_VERSION . , zlib.h, . deflateInit inflateInit.

int deflateInit (z_streamp strm, int level);

state. zalloc, zfree opaque . zalloc zfree Z_NULL, deflateInit .., .
level Z_DEFAULT_COMPRESSION, 0 9: 1 , 9 , 0 ( ).
Z_DEFAULT_COMPRESSION ( 6 level).
deflateInit :

• Z_OK
• Z_MEM_ERROR
• Z_STREAM_ERROR level
• Z_VERSION_ERROR zlib (zlib_version) , (ZLIB_VERSION).

msg null, .
deflateInit , deflate().

int deflate (z_streamp strm, int flush);

deflate , , . (.. - ) , .
. deflate :

• next_in, next_in avail_in . (- ), next_in avail_in deflate().
• next_out, next_out avail_out . , flush . flush , , . ( , ). , flush .

deflate(), , (\) , .. , avail_in avail_out ; avail_out . , , , , (.. avail_out == 0), deflate(). deflate Z_OK avail_out, , , .. .

flush Z_SYNC_FLUSH, , , .. . ( , avail_in , .) , .

flush Z_FULL_FLUSH, , Z_SYNC_FLUSH, state .., , . Z_FULL_FLUSH .

deflate avail_out == 0, flush ( avail_out), (deflate avail_out).

flush Z_FINISH, , deflate Z_STREAM_END ; deflate Z_OK, Z_FINISH ( avail_out) , . Z_STREAM_END . deflate Z_STREAM_END, deflateReset deflateEnd.

Z_FINISH deflateInit . avail_out 0.1% avail_in 12 . deflate Z_STREAM_END, , .

deflate() strm-&gt adler adler32 (., total_in ).

deflate() data_type (Z_ASCII Z_BINARY). . .

deflate() :

• Z_OK - (.. - - )
• Z_STREAM_END ( flush Z_FINISH)
• Z_STREAM_ERROR state ( , next_in next_out NULL)
• Z_BUF_ERROR ( avail_in avail_out ).

int deflateEnd (z_streamp strm);

, . .

deflateEnd :

• Z_OK
• Z_STREAM_ERROR state
• Z_DATA_ERROR (.. ).

msg , ( ).

int inflateInit (z_streamp strm);

state . next_in, avail_in, zalloc, zfree opaque . next_in Z_NULL avail_in ( ), inflateInit zlib ; , inflate. zalloc zfree Z_NULL, inflateInit .., .

inflateInit :

• Z_OK
• Z_MEM_ERROR
• Z_VERSION_ERROR zlib , .

msg NULL, - . inflateInit - , zlib , . inflate(). (.. next_in avail_in , next_out avail_out .)

int inflate (z_streamp strm, int flush);

inflate , , . ( - ) , flush .

. inflate :

• , next_in, next_in avail_in . ( - ), next_in inflate().
• , next_out, next_out avail_out . inflate() , , .. . ( flush ).

inflate(), , , , , - next_* avail_*. , , (.. avail_out == 0), inflate(). inflate Z_OK avail_out, , , .

flush Z_SYNC_FLUSH, inflate , . inflate flush, Z_SYNC_FLUSH Z_FINISH, ,

inflate() , Z_STREAM_END . , , flush Z_FINISH. ; avail_out , . ( ). inflateEnd - state. Z_FINISH , inflate(), .

(. inflateSetDictionary ), inflate strm->adler adler32 Z_NEED_DICT; strm->adler adler32 (.. total_out ) Z_OK, Z_STREAM_END , . inflate() adler32 , Z_STREAM_END.

inflate() :

• Z_OK - ( )
• Z_STREAM_END .
• Z_NEED_DICT .
• Z_DATA_ERROR ( zlib adler32 )
• Z_STREAM_ERROR ( next_in next_out NULL)
• Z_MEM_ERROR
• Z_BUF_ERROR Z_FINISH.

Z_DATA_ERROR, inflateSync .

int inflateEnd (z_streamp strm);

. .

inflateEnd :

• Z_OK
• Z_STREAM_ERROR state .

msg , ( ).

• int deflateInit2 (z_streamp strm, int level, int method, int windowBits, int memLevel, int strategy);
• int deflateSetDictionary (z_streamp strm, const Bytef *dictionary, uInt dictLength);
• int deflateCopy (z_streamp dest, z_streamp source);
• int deflateReset (z_streamp strm);
• int deflateParams (z_streamp strm, int level, int strategy);
• int inflateInit2 (z_streamp strm, int windowBits);
• int inflateSetDictionary (z_streamp strm, const Bytef *dictionary, uInt dictLength);
• int inflateSync (z_streamp strm);
• int inflateReset (z_streamp strm);

int deflateInit2 (z_streamp strm, int level, int method, int windowBits, int memLevel, int strategy);

deflateInit . next_in, zalloc, zfree opaque .

method . Z_DEFLATED.

windowBits ( ). 8..15 . . deflateInit 15.

memLevel state. memLevel=1 , ; memLevel=9 . - 8. windowBits memLevel zconf.h.

strategy . Z_DEFAULT_STRATEGY , Z_FILTERED , ( ), Z_HUFFMAN_ONLY ( ). - . - compress. Z_FILTERED ; - Z_DEFAULT Z_HUFFMAN_ONLY. strategy .

deflateInit2 :

• Z_OK
• Z_MEM_ERROR
• Z_STREAM_ERROR - ( ).

msg NULL . deflateInit2 - : deflate().

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

- \. deflateInit, deflateInit2 deflateReset, deflate. (. inflateSetDictionary).

( ) . , . , ; , , .

deflateInit deflateInit2 , , , deflate deflate2. .. , , , .

strm->adler Adler32 ; , , . (Adler32 , .)

deflateSetDictionary :

• Z_OK
• Z_STREAM_ERROR - ( dictionary NULL) state ( , deflate bsort).

deflateSetDictionary - , deflate().

int deflateCopy (z_streamp dest, z_streamp source);

.

, , , . , , deflateEnd. , deflateCopy state, , .

deflateCopy :

• Z_OK
• Z_MEM_ERROR
• Z_STREAM_ERROR state ( zalloc NULL).

msg .

int deflateReset (z_streamp strm);

deflateEnd deflateInit, state. level deflateInit2.

deflateReset :

• Z_OK
• Z_STREAM_ERROR state ( zalloc state NULL).

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

level strategy. deflateInit2. , . level , deflate().

deflateParams, state deflate(), . , strm->avail_out .

deflateParams :

• Z_OK
• Z_STREAM_ERROR state - Z_BUF_ERROR strm->avail_out .

int inflateInit2 (z_streamp strm, int windowBits);

inflateInit . next_in, avail_in, zalloc, zfree and opaque .

The windowBits parameter ( ). 8..15 . - 15, - inflateInit. , inflate() Z_DATA_ERROR .

inflateInit2 :

• Z_OK
• Z_MEM_ERROR
• Z_STREAM_ERROR -

msg NULL, - . inflateInit2 - , zlib , . inflate(). (.. next_in avail_in , next_out avail_out .)

int inflateSetDictionary (z_streamp strm, const Bytef *dictionary, uInt dictLength);

. inflate, Z_NEED_DICT. , , Adler32 . (. deflateSetDictionary).

inflateSetDictionary :

• Z_OK
• Z_STREAM_ERROR - , ( dictionary NULL) state
• Z_DATA_ERROR ( Adler32 ).

inflateSetDictionary - , inflate().

int inflateSync (z_streamp strm);

(. deflate Z_FULL_FLUSH). . .

inflateSync :

• Z_OK
• Z_BUF_ERROR
• Z_DATA_ERROR
• Z_STREAM_ERROR

total_in, . inflateSync, , , .

int inflateReset (z_streamp strm);

inflateEnd inflateInit, state. , inflateInit2.

inflateReset :

• Z_OK
• Z_STREAM_ERROR state ( zalloc state NULL).

• uLong adler32 (uLong adler, const Bytef *buf, uInt len);
• uLong crc32 (uLong crc, const Bytef *buf, uInt len);

uLong adler32 (uLong adler, const Bytef *buf, uInt len);

Adler-32 buf[0..len-1] . buf NULL, .

Adler-32 , CRC32, . :

     uLong adler = adler32(0L, Z_NULL, 0);

     while (read_buffer(buffer, length) != EOF) {
       adler = adler32(adler, buffer, length);
     }
     if (adler != original_adler) error();
   

uLong crc32 (uLong crc, const Bytef *buf, uInt len);

buf[0..len-1] . buf NULL, . :

     uLong crc = crc32(0L, Z_NULL, 0);

     while (read_buffer(buffer, length) != EOF) {
       crc = crc32(crc, buffer, length);
     }
     if (crc != original_crc) error();
   

typedef struct z_stream_s {
    Bytef    *next_in;  /* next input byte */
    uInt     avail_in;  /* number of bytes available at next_in */
    uLong    total_in;  /* total nb of input bytes read so far */

    Bytef    *next_out; /* next output byte should be put there */
    uInt     avail_out; /* remaining free space at next_out */
    uLong    total_out; /* total nb of bytes output so far */

    char     *msg;      /* last error message, NULL if no error */
    struct internal_state FAR *state; /* not visible by applications */

    alloc_func zalloc;  /* used to allocate the internal state */
    free_func  zfree;   /* used to free the internal state */
    voidpf     opaque;  /* private data object passed to zalloc and zfree */

    int     data_type;  /* best guess about the data type: ascii or binary */
    uLong   adler;      /* adler32 value of the uncompressed data */
    uLong   reserved;   /* reserved for future use */
} z_stream ;

typedef z_stream FAR * z_streamp;   

opaque, , zalloc zfree. . opaque .

zalloc Z_NULL . zlib , zalloc zfree .

16- , zalloc zfree 65536 , , MAXSEG_64K (.zconf.h). : MSDOS, , zalloc 65536 ** 0. (. zutil.c). 64K, , -DMAX_WBITS=14 (. zconf.h).

total_in total_out . , total_in ( , ).

#define Z_NO_FLUSH      0
#define Z_PARTIAL_FLUSH 1 
	/* will be removed, use Z_SYNC_FLUSH instead */
#define Z_SYNC_FLUSH    2
#define Z_FULL_FLUSH    3
#define Z_FINISH        4
/* Allowed flush values ; see deflate() below for details */

#define Z_OK            0
#define Z_STREAM_END    1
#define Z_NEED_DICT     2
#define Z_ERRNO        (-1)
#define Z_STREAM_ERROR (-2)
#define Z_DATA_ERROR   (-3)
#define Z_MEM_ERROR    (-4)
#define Z_BUF_ERROR    (-5)
#define Z_VERSION_ERROR (-6)
/* Return codes for the compression/decompression functions. Negative
 * values are errors, positive values are used for special but normal events.
 */

#define Z_NO_COMPRESSION         0
#define Z_BEST_SPEED             1
#define Z_BEST_COMPRESSION       9
#define Z_DEFAULT_COMPRESSION  (-1)
/* compression levels */

#define Z_FILTERED            1
#define Z_HUFFMAN_ONLY        2
#define Z_DEFAULT_STRATEGY    0
/* compression strategy ; see deflateInit2() below for details */

#define Z_BINARY   0
#define Z_ASCII    1
#define Z_UNKNOWN  2
/* Possible values of the data_type field */

#define Z_DEFLATED   8
/* The deflate compression method (the only one supported in this version) */

#define Z_NULL  0  /* for initializing zalloc, zfree, opaque */

#define zlib_version zlibVersion()
/* for compatibility with versions less than 1.0.2 */

, :

const char * zError (int err);

int inflateSyncPoint (z_streamp z);

const uLongf * get_crc_table (void);