Lines Matching +full:zlib +full:- +full:level
1 /* zlib.h -- interface of the 'zlib' general purpose compression library
4 Copyright (C) 1995-2017 Jean-loup Gailly and Mark Adler
6 This software is provided 'as-is', without any express or implied
22 Jean-loup Gailly Mark Adler
26 The data format used by the zlib library is described by RFCs (Request for
28 (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format).
48 The 'zlib' compression library provides in-memory compression and
59 The compressed data format used by default by the in-memory functions is
60 the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped
65 with "gz". The gzip format is different from the zlib format. gzip is a
71 The zlib format was designed to be compact and fast for use in memory
72 and on communications channels. The gzip format was designed for single-
73 file compression on file systems, has a larger header than zlib to maintain
74 directory information, and uses a different, slower check method than zlib.
104 uLong adler; /* Adler-32 or CRC-32 value of the uncompressed data */
111 gzip header information passed to and from zlib routines. See RFC 1952
122 Bytef *name; /* pointer to zero-terminated file name or Z_NULL */
124 Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */
146 If zlib is used in a multi-threaded application, zalloc and zfree must be
147 thread safe. In that case, zlib is thread-safe. When zalloc and zfree are
151 On 16-bit systems, the functions zalloc and zfree must be able to allocate
158 the library with -DMAX_WBITS=14 (see zconf.h).
180 #define Z_ERRNO (-1)
181 #define Z_STREAM_ERROR (-2)
182 #define Z_DATA_ERROR (-3)
183 #define Z_MEM_ERROR (-4)
184 #define Z_BUF_ERROR (-5)
185 #define Z_VERSION_ERROR (-6)
193 #define Z_DEFAULT_COMPRESSION (-1)
223 compatible with the zlib.h header file used by the application. This check
228 ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
235 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
239 equivalent to level 6).
242 memory, Z_STREAM_ERROR if level is not a valid compression level, or
243 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
260 - Compress more input starting at next_in and update next_in and avail_in
265 - Generate more output starting at next_out and update next_out and avail_out
321 avail_out), until the flush is complete (deflate returns with non-zero
341 deflate() sets strm->adler to the Adler-32 checksum of all input read
343 strm->adler will be the CRC-32 checksum of the input read so far. (See
346 deflate() may update strm->data_type if it can make a good guess about
389 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
395 implementation of inflateInit() does not process any header information --
410 - Decompress more input starting at next_in and update next_in and avail_in
416 - Generate more output starting at next_out and update next_out and avail_out
436 the zlib or gzip format, this will cause inflate() to return immediately
442 To assist in this, on return inflate() always sets strm->data_type to the
443 number of unused bits in the last byte taken from strm->next_in, plus 64 if
445 128 if inflate() returned immediately after decoding an end-of-block code or
447 stream. The end-of-block will not be indicated until all of the uncompressed
448 data from that block has been written to strm->next_out. The number of
459 256 is added to the value of strm->data_type when inflate() returns
486 below), inflate sets strm->adler to the Adler-32 checksum of the dictionary
488 strm->adler to the Adler-32 checksum of all output produced so far (that is,
490 below. At the end of the stream, inflate() checks that its computed Adler-32
494 inflate() can decompress and check either zlib-wrapped or gzip-wrapped
498 gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output
499 produced so far. The CRC-32 is checked against the gzip trailer, as is the
506 corrupted (input stream not conforming to the zlib format or incorrect check
507 value, in which case strm->msg points to a string with a more specific
539 int level,
560 will result in 9 (a 512-byte window). In that case, providing 8 to
561 inflateInit2() will result in an error when the zlib header with 9 is
566 windowBits can also be -8..-15 for raw deflate. In this case, -windowBits
568 with no zlib header or trailer, and will not compute a check value.
572 compressed data instead of a zlib wrapper. The gzip header will have no
576 being written, strm->adler is a CRC-32 instead of an Adler-32.
578 For raw deflate or gzip encoding, a request for a 256-byte window is
579 rejected as invalid, since only the zlib header provides a means of
591 string match), or Z_RLE to limit match distances to one (run-length
605 method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is
616 without producing any compressed output. When using the zlib format, this
641 Upon return of this function, strm->adler is set to the Adler-32 value
643 which dictionary has been used by the compressor. (The Adler-32 value
646 Adler-32 value is not computed and strm->adler is not set.
668 to 258 bytes less in that case, due to how zlib's implementation of deflate
670 up to 258 bytes long. If the application needs the last window-size bytes of
671 input, then that would need to be saved by the application outside of zlib.
683 tried, for example when there are several ways of pre-processing the input
699 will leave the compression level and any other attributes that may have been
707 int level,
710 Dynamically update the compression level and compression strategy. The
711 interpretation of level and strategy is as in deflateInit2(). This can be
714 If the compression approach (which is a function of the level) or the
717 level and strategy using deflate(strm, Z_BLOCK). There are three approaches
718 for the compression levels 0, 1..3, and 4..9 respectively. The new level
730 If this is done, the old level and strategy will be applied to the data
731 compressed before deflateParams(), and the new level and strategy will be
750 used by someone who understands the algorithm used by zlib's deflate for
815 ignored -- the extra flags are set according to the compression level). The
819 the current versions of the command-line version of gzip (up through version
820 1.3.x) do not support header crc's, and will report that it is a "multi-part
849 the zlib header of the compressed stream.
851 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits
853 not looking for a zlib or gzip header, not generating a check value, and not
858 recommended that a check value such as an Adler-32 or a CRC-32 be applied to
859 the uncompressed data as is done in the zlib, gzip, and zip formats. For
860 most applications, the zlib format should be used as is. Note that comments
864 32 to windowBits to enable zlib and gzip decoding with automatic header
865 detection, or add 16 to decode only the gzip format (the zlib format will
866 return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a
867 CRC-32 instead of an Adler-32. Unlike the gunzip utility and gzread() (see
873 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
877 apart from possibly reading the zlib header if present: actual decompression
880 of inflateInit2() does not process any header information -- that is
891 can be determined from the Adler-32 value returned by that call of inflate.
902 expected one (incorrect Adler-32 value). inflateSetDictionary does not
1006 return value down 16 bits. If the upper value is -1 and the lower value is
1008 If the upper value is -1 and the lower value is non-zero, then inflate is in
1010 bytes from the input remaining to copy. If the upper value is not -1, then
1026 inflateMark returns the value noted above, or -65536 if the provided
1036 As inflate() processes the gzip stream, head->done is zero until the header
1037 is completed, at which time head->done is set to one. If a zlib stream is
1038 being decoded, then head->done is set to -1 to indicate that there will be
1076 before the call. If zalloc and zfree are Z_NULL, then the default library-
1100 inflateBack() does a raw inflate with a single call using a call-back
1109 and to initialize the state with the user-provided window buffer.
1114 A raw deflate stream is one with no zlib or gzip header or trailer.
1119 behavior of inflate(), which expects a zlib header and trailer around the
1129 there is no input available, in() must return zero -- buf is ignored in that
1130 case -- and inflateBack() will return a buffer error. inflateBack() will
1131 call out(out_desc, buf, len) to write the uncompressed data buf[0..len-1].
1132 out() should return zero on success, or non-zero on failure. If out()
1133 returns non-zero, inflateBack() will return with an error. Neither in() nor
1136 The length written by out() will be at most the window size. Any non-zero
1140 setting strm->next_in and strm->avail_in. If that input is exhausted, then
1141 in() will be called. Therefore strm->next_in must be initialized before
1142 calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called
1143 immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in
1144 must also be initialized, and then if strm->avail_in is not zero, input will
1145 initially be taken from strm->next_in[0 .. strm->avail_in - 1].
1149 descriptors can be optionally used to pass any information that the caller-
1152 On return, inflateBack() will set strm->next_in and strm->avail_in to
1156 in the deflate stream (in which case strm->msg is set to indicate the nature
1159 using strm->next_in which will be Z_NULL only if in() returned an error. If
1160 strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning
1161 non-zero. (in() will always be called before out(), so strm->next_in is
1162 assured to be defined if out() returns non-zero.) Note that inflateBack()
1175 /* Return flags indicating compile-time options.
1185 9: ASMV or ASMINF -- use ASM code
1186 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention
1189 One-time table building (smaller code, but not thread-safe if true):
1190 12: BUILDFIXED -- build static block decoding tables when needed
1191 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed
1195 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking
1197 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect
1199 18-19: 0 (reserved)
1202 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate
1203 21: FASTEST -- deflate algorithm with only one, lowest compression level
1207 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format
1208 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!
1209 26: 0 = returns value, 1 = void -- 1 means inferred string length returned
1212 27-31: 0 (reserved)
1221 stream-oriented functions. To simplify the interface, some default options
1222 are assumed (compression level and memory usage, standard memory allocation
1234 compressed data. compress() is equivalent to compress2() with a level
1244 int level));
1246 Compresses the source buffer into the destination buffer. The level
1255 Z_STREAM_ERROR if the level parameter is invalid.
1296 "gz". The gzip format is different from the zlib format. gzip is a gzip
1300 typedef struct gzFile_s *gzFile; /* semi-opaque gzip file descriptor */
1306 in fopen ("rb" or "wb") but can also include a compression level ("wb9") or
1307 a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only
1308 compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F'
1330 reading, this will be detected automatically by looking for the magic two-
1352 double-close()ing the file descriptor. Both gzclose() and fclose() will
1358 provided, or '+' was provided), or if fd is -1. The file descriptor is not
1360 will not detect if fd is invalid (unless fd is -1).
1375 gzbuffer() returns 0 on success, or -1 on failure, such as being called
1379 ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
1381 Dynamically update the compression level or strategy. See the description
1408 middle of a gzip stream. Note that gzread does not return -1 in the event
1415 len for end of file, or -1 for error. If len is too large to fit in an int,
1416 then nothing is read, -1 is returned, and the error state is set to
1439 and the end-of-file flag is set. The length of the partial item read is not
1443 file, reseting and retrying on end-of-file, when size is not 1.
1472 uncompressed bytes actually written, or a negative zlib error code in case
1478 zlib was compiled with the insecure functions sprintf() or vsprintf()
1485 Writes the given null-terminated string to the compressed file, excluding
1488 gzputs returns the number of characters written, or -1 in case of error.
1493 Reads bytes from the compressed file until len-1 characters are read, or a
1494 newline character is read and transferred to buf, or an end-of-file
1497 to an end-of-file or len < 1, then the buffer is left untouched.
1499 gzgets returns buf which is a null-terminated string, or it returns NULL
1500 for end-of-file or in case of error. If there was an error, the contents at
1507 returns the value that was written, or -1 in case of error.
1512 Reads one byte from the compressed file. gzgetc returns this byte or -1
1522 on the next read. At least one character of push-back is allowed.
1523 gzungetc() returns the character pushed, or -1 on failure. gzungetc() will
1524 fail if c is -1, and may fail if a character has been pushed but not read
1534 is as in the deflate() function. The return value is the zlib error number
1561 the beginning of the uncompressed stream, or -1 in case of error, in
1591 for a progress indicator. On error, gzoffset() returns -1.
1596 Returns true (1) if the end-of-file indicator has been set while reading,
1597 false (0) otherwise. Note that the end-of-file indicator is set only if the
1605 unless the end-of-file indicator is reset by gzclearerr() and the input file
1626 linking statically, using gzdirect() will include all of the zlib code for
1648 using these instead of gzclose() is that they avoid linking in zlib
1652 zlib library.
1658 compressed file. errnum is set to zlib error number. If an error occurred
1667 gzerror() should be used to distinguish errors from end-of-file for those
1673 Clears the error and end-of-file flags for file. This is analogous to the
1690 Update a running Adler-32 checksum with the bytes buf[0..len-1] and
1694 An Adler-32 checksum is almost as reliable as a CRC-32 but can be computed
1717 Combine two Adler-32 checksums into one. For two sequences of bytes, seq1
1718 and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for
1719 each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of
1727 Update a running CRC-32 with the bytes buf[0..len-1] and return the
1728 updated CRC-32. If buf is Z_NULL, this function returns the required
1729 initial value for the crc. Pre- and post-conditioning (one's complement) is
1751 Combine two CRC-32 check values into one. For two sequences of bytes,
1752 seq1 and seq2 with lengths len1 and len2, CRC-32 check values were
1753 calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32
1761 /* deflateInit and inflateInit are macros to allow checking the zlib version
1764 ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level,
1768 ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method,
1779 # define z_deflateInit(strm, level) \ argument
1780 deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream))
1783 # define z_deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ argument
1784 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
1793 # define deflateInit(strm, level) \ argument
1794 deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream))
1797 # define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ argument
1798 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
1826 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g))
1829 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g))
1832 /* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or
1835 * functions are changed to 64 bits) -- in case these are set on systems