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|
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>zlib - Chicken - SWIG example</title>
</head>
<body>
<center><h1>zlib - Chicken - SWIG</h1></center>
<h2>Table of Contents</h2>
<a href="#build">Building the example</a><br>
<a href="#zlibh">zlib.h</a><br>
<a href="#devel">How the zlib wrapper was developed</a><br>
<center><h2><a name="build">Building the example</a></h2></center>
zlib must be installed for this example to work.<br>
Just type <code>make</code> to build this example.<br>
If zlib is not installed in /usr/lib and /usr/include, then do
something similar to the following:
<blockquote>
<pre>make SWIGOPT="-I/usr/local/include" LIBS="-L/usr/local/lib -lz"</pre>
</blockquote>
<center><h2><a name="zlibh">zlib.h</a></h2></center>
<blockquote>
<pre>
<font color="blue">001:</font> /* zlib.h -- interface of the 'zlib' general purpose compression library
<font color="blue">002:</font> version 1.1.4, March 11th, 2002
<font color="blue">003:</font>
<font color="blue">004:</font> Copyright (C) 1995-2002 Jean-loup Gailly and Mark Adler
<font color="blue">005:</font>
<font color="blue">006:</font> This software is provided 'as-is', without any express or implied
<font color="blue">007:</font> warranty. In no event will the authors be held liable for any damages
<font color="blue">008:</font> arising from the use of this software.
<font color="blue">009:</font>
<font color="blue">010:</font> Permission is granted to anyone to use this software for any purpose,
<font color="blue">011:</font> including commercial applications, and to alter it and redistribute it
<font color="blue">012:</font> freely, subject to the following restrictions:
<font color="blue">013:</font>
<font color="blue">014:</font> 1. The origin of this software must not be misrepresented; you must not
<font color="blue">015:</font> claim that you wrote the original software. If you use this software
<font color="blue">016:</font> in a product, an acknowledgment in the product documentation would be
<font color="blue">017:</font> appreciated but is not required.
<font color="blue">018:</font> 2. Altered source versions must be plainly marked as such, and must not be
<font color="blue">019:</font> misrepresented as being the original software.
<font color="blue">020:</font> 3. This notice may not be removed or altered from any source distribution.
<font color="blue">021:</font>
<font color="blue">022:</font> Jean-loup Gailly Mark Adler
<font color="blue">023:</font> jloup@gzip.org madler@alumni.caltech.edu
<font color="blue">024:</font>
<font color="blue">025:</font>
<font color="blue">026:</font> The data format used by the zlib library is described by RFCs (Request for
<font color="blue">027:</font> Comments) 1950 to 1952 in the files ftp://ds.internic.net/rfc/rfc1950.txt
<font color="blue">028:</font> (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format).
<font color="blue">029:</font> */
<font color="blue">030:</font>
<font color="blue">031:</font> #ifndef _ZLIB_H
<font color="blue">032:</font> #define _ZLIB_H
<font color="blue">033:</font>
<font color="blue">034:</font> #include "zconf.h"
<font color="blue">035:</font>
<font color="blue">036:</font> #ifdef __cplusplus
<font color="blue">037:</font> extern "C" {
<font color="blue">038:</font> #endif
<font color="blue">039:</font>
<font color="blue">040:</font> #define ZLIB_VERSION "1.1.4"
<font color="blue">041:</font>
<font color="blue">042:</font> /*
<font color="blue">043:</font> The 'zlib' compression library provides in-memory compression and
<font color="blue">044:</font> decompression functions, including integrity checks of the uncompressed
<font color="blue">045:</font> data. This version of the library supports only one compression method
<font color="blue">046:</font> (deflation) but other algorithms will be added later and will have the same
<font color="blue">047:</font> stream interface.
<font color="blue">048:</font>
<font color="blue">049:</font> Compression can be done in a single step if the buffers are large
<font color="blue">050:</font> enough (for example if an input file is mmap'ed), or can be done by
<font color="blue">051:</font> repeated calls of the compression function. In the latter case, the
<font color="blue">052:</font> application must provide more input and/or consume the output
<font color="blue">053:</font> (providing more output space) before each call.
<font color="blue">054:</font>
<font color="blue">055:</font> The library also supports reading and writing files in gzip (.gz) format
<font color="blue">056:</font> with an interface similar to that of stdio.
<font color="blue">057:</font>
<font color="blue">058:</font> The library does not install any signal handler. The decoder checks
<font color="blue">059:</font> the consistency of the compressed data, so the library should never
<font color="blue">060:</font> crash even in case of corrupted input.
<font color="blue">061:</font> */
<font color="blue">062:</font>
<font color="blue"><a name="l63">063:</a></font> typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
<font color="blue">064:</font> typedef void (*free_func) OF((voidpf opaque, voidpf address));
<font color="blue">065:</font>
<font color="blue">066:</font> struct internal_state;
<font color="blue">067:</font>
<font color="blue">068:</font> typedef struct z_stream_s {
<font color="blue">069:</font> Bytef *next_in; /* next input byte */
<font color="blue">070:</font> uInt avail_in; /* number of bytes available at next_in */
<font color="blue">071:</font> uLong total_in; /* total nb of input bytes read so far */
<font color="blue">072:</font>
<font color="blue">073:</font> Bytef *next_out; /* next output byte should be put there */
<font color="blue">074:</font> uInt avail_out; /* remaining free space at next_out */
<font color="blue">075:</font> uLong total_out; /* total nb of bytes output so far */
<font color="blue">076:</font>
<font color="blue">077:</font> char *msg; /* last error message, NULL if no error */
<font color="blue"><a name="l78">078:</a></font> struct internal_state FAR *state; /* not visible by applications */
<font color="blue">079:</font>
<font color="blue"><a name="l80">080:</a></font> alloc_func zalloc; /* used to allocate the internal state */
<font color="blue">081:</font> free_func zfree; /* used to free the internal state */
<font color="blue">082:</font> voidpf opaque; /* private data object passed to zalloc and zfree */
<font color="blue">083:</font>
<font color="blue">084:</font> int data_type; /* best guess about the data type: ascii or binary */
<font color="blue">085:</font> uLong adler; /* adler32 value of the uncompressed data */
<font color="blue">086:</font> uLong reserved; /* reserved for future use */
<font color="blue">087:</font> } z_stream;
<font color="blue">088:</font>
<font color="blue">089:</font> typedef z_stream FAR *z_streamp;
<font color="blue">090:</font>
<font color="blue">091:</font> /*
<font color="blue">092:</font> The application must update next_in and avail_in when avail_in has
<font color="blue">093:</font> dropped to zero. It must update next_out and avail_out when avail_out
<font color="blue">094:</font> has dropped to zero. The application must initialize zalloc, zfree and
<font color="blue">095:</font> opaque before calling the init function. All other fields are set by the
<font color="blue">096:</font> compression library and must not be updated by the application.
<font color="blue">097:</font>
<font color="blue">098:</font> The opaque value provided by the application will be passed as the first
<font color="blue">099:</font> parameter for calls of zalloc and zfree. This can be useful for custom
<font color="blue">100:</font> memory management. The compression library attaches no meaning to the
<font color="blue">101:</font> opaque value.
<font color="blue">102:</font>
<font color="blue">103:</font> zalloc must return Z_NULL if there is not enough memory for the object.
<font color="blue">104:</font> If zlib is used in a multi-threaded application, zalloc and zfree must be
<font color="blue">105:</font> thread safe.
<font color="blue">106:</font>
<font color="blue">107:</font> On 16-bit systems, the functions zalloc and zfree must be able to allocate
<font color="blue">108:</font> exactly 65536 bytes, but will not be required to allocate more than this
<font color="blue">109:</font> if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS,
<font color="blue">110:</font> pointers returned by zalloc for objects of exactly 65536 bytes *must*
<font color="blue">111:</font> have their offset normalized to zero. The default allocation function
<font color="blue">112:</font> provided by this library ensures this (see zutil.c). To reduce memory
<font color="blue">113:</font> requirements and avoid any allocation of 64K objects, at the expense of
<font color="blue">114:</font> compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).
<font color="blue">115:</font>
<font color="blue">116:</font> The fields total_in and total_out can be used for statistics or
<font color="blue">117:</font> progress reports. After compression, total_in holds the total size of
<font color="blue">118:</font> the uncompressed data and may be saved for use in the decompressor
<font color="blue">119:</font> (particularly if the decompressor wants to decompress everything in
<font color="blue">120:</font> a single step).
<font color="blue">121:</font> */
<font color="blue">122:</font>
<font color="blue">123:</font> /* constants */
<font color="blue">124:</font>
<font color="blue">125:</font> #define Z_NO_FLUSH 0
<font color="blue">126:</font> #define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */
<font color="blue">127:</font> #define Z_SYNC_FLUSH 2
<font color="blue">128:</font> #define Z_FULL_FLUSH 3
<font color="blue">129:</font> #define Z_FINISH 4
<font color="blue">130:</font> /* Allowed flush values; see deflate() below for details */
<font color="blue">131:</font>
<font color="blue">132:</font> #define Z_OK 0
<font color="blue">133:</font> #define Z_STREAM_END 1
<font color="blue">134:</font> #define Z_NEED_DICT 2
<font color="blue">135:</font> #define Z_ERRNO (-1)
<font color="blue">136:</font> #define Z_STREAM_ERROR (-2)
<font color="blue">137:</font> #define Z_DATA_ERROR (-3)
<font color="blue">138:</font> #define Z_MEM_ERROR (-4)
<font color="blue">139:</font> #define Z_BUF_ERROR (-5)
<font color="blue">140:</font> #define Z_VERSION_ERROR (-6)
<font color="blue">141:</font> /* Return codes for the compression/decompression functions. Negative
<font color="blue">142:</font> * values are errors, positive values are used for special but normal events.
<font color="blue">143:</font> */
<font color="blue">144:</font>
<font color="blue">145:</font> #define Z_NO_COMPRESSION 0
<font color="blue">146:</font> #define Z_BEST_SPEED 1
<font color="blue">147:</font> #define Z_BEST_COMPRESSION 9
<font color="blue">148:</font> #define Z_DEFAULT_COMPRESSION (-1)
<font color="blue">149:</font> /* compression levels */
<font color="blue">150:</font>
<font color="blue">151:</font> #define Z_FILTERED 1
<font color="blue">152:</font> #define Z_HUFFMAN_ONLY 2
<font color="blue">153:</font> #define Z_DEFAULT_STRATEGY 0
<font color="blue">154:</font> /* compression strategy; see deflateInit2() below for details */
<font color="blue">155:</font>
<font color="blue">156:</font> #define Z_BINARY 0
<font color="blue">157:</font> #define Z_ASCII 1
<font color="blue">158:</font> #define Z_UNKNOWN 2
<font color="blue">159:</font> /* Possible values of the data_type field */
<font color="blue">160:</font>
<font color="blue">161:</font> #define Z_DEFLATED 8
<font color="blue">162:</font> /* The deflate compression method (the only one supported in this version) */
<font color="blue">163:</font>
<font color="blue">164:</font> #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */
<font color="blue">165:</font>
<font color="blue">166:</font> #define zlib_version zlibVersion()
<font color="blue">167:</font> /* for compatibility with versions < 1.0.2 */
<font color="blue">168:</font>
<font color="blue">169:</font> /* basic functions */
<font color="blue">170:</font>
<font color="blue">171:</font> ZEXTERN const char * ZEXPORT zlibVersion OF((void));
<font color="blue">172:</font> /* The application can compare zlibVersion and ZLIB_VERSION for consistency.
<font color="blue">173:</font> If the first character differs, the library code actually used is
<font color="blue">174:</font> not compatible with the zlib.h header file used by the application.
<font color="blue">175:</font> This check is automatically made by deflateInit and inflateInit.
<font color="blue">176:</font> */
<font color="blue">177:</font>
<font color="blue">178:</font> /*
<font color="blue">179:</font> ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
<font color="blue">180:</font>
<font color="blue">181:</font> Initializes the internal stream state for compression. The fields
<font color="blue">182:</font> zalloc, zfree and opaque must be initialized before by the caller.
<font color="blue">183:</font> If zalloc and zfree are set to Z_NULL, deflateInit updates them to
<font color="blue">184:</font> use default allocation functions.
<font color="blue">185:</font>
<font color="blue">186:</font> The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
<font color="blue">187:</font> 1 gives best speed, 9 gives best compression, 0 gives no compression at
<font color="blue">188:</font> all (the input data is simply copied a block at a time).
<font color="blue">189:</font> Z_DEFAULT_COMPRESSION requests a default compromise between speed and
<font color="blue">190:</font> compression (currently equivalent to level 6).
<font color="blue">191:</font>
<font color="blue">192:</font> deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
<font color="blue">193:</font> enough memory, Z_STREAM_ERROR if level is not a valid compression level,
<font color="blue">194:</font> Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
<font color="blue">195:</font> with the version assumed by the caller (ZLIB_VERSION).
<font color="blue">196:</font> msg is set to null if there is no error message. deflateInit does not
<font color="blue">197:</font> perform any compression: this will be done by deflate().
<font color="blue">198:</font> */
<font color="blue">199:</font>
<font color="blue">200:</font>
<font color="blue">201:</font> ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
<font color="blue">202:</font> /*
<font color="blue">203:</font> deflate compresses as much data as possible, and stops when the input
<font color="blue">204:</font> buffer becomes empty or the output buffer becomes full. It may introduce some
<font color="blue">205:</font> output latency (reading input without producing any output) except when
<font color="blue">206:</font> forced to flush.
<font color="blue">207:</font>
<font color="blue">208:</font> The detailed semantics are as follows. deflate performs one or both of the
<font color="blue">209:</font> following actions:
<font color="blue">210:</font>
<font color="blue">211:</font> - Compress more input starting at next_in and update next_in and avail_in
<font color="blue">212:</font> accordingly. If not all input can be processed (because there is not
<font color="blue">213:</font> enough room in the output buffer), next_in and avail_in are updated and
<font color="blue">214:</font> processing will resume at this point for the next call of deflate().
<font color="blue">215:</font>
<font color="blue">216:</font> - Provide more output starting at next_out and update next_out and avail_out
<font color="blue">217:</font> accordingly. This action is forced if the parameter flush is non zero.
<font color="blue">218:</font> Forcing flush frequently degrades the compression ratio, so this parameter
<font color="blue">219:</font> should be set only when necessary (in interactive applications).
<font color="blue">220:</font> Some output may be provided even if flush is not set.
<font color="blue">221:</font>
<font color="blue">222:</font> Before the call of deflate(), the application should ensure that at least
<font color="blue">223:</font> one of the actions is possible, by providing more input and/or consuming
<font color="blue">224:</font> more output, and updating avail_in or avail_out accordingly; avail_out
<font color="blue">225:</font> should never be zero before the call. The application can consume the
<font color="blue">226:</font> compressed output when it wants, for example when the output buffer is full
<font color="blue">227:</font> (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK
<font color="blue">228:</font> and with zero avail_out, it must be called again after making room in the
<font color="blue">229:</font> output buffer because there might be more output pending.
<font color="blue">230:</font>
<font color="blue">231:</font> If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
<font color="blue">232:</font> flushed to the output buffer and the output is aligned on a byte boundary, so
<font color="blue">233:</font> that the decompressor can get all input data available so far. (In particular
<font color="blue">234:</font> avail_in is zero after the call if enough output space has been provided
<font color="blue">235:</font> before the call.) Flushing may degrade compression for some compression
<font color="blue">236:</font> algorithms and so it should be used only when necessary.
<font color="blue">237:</font>
<font color="blue">238:</font> If flush is set to Z_FULL_FLUSH, all output is flushed as with
<font color="blue">239:</font> Z_SYNC_FLUSH, and the compression state is reset so that decompression can
<font color="blue">240:</font> restart from this point if previous compressed data has been damaged or if
<font color="blue">241:</font> random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
<font color="blue">242:</font> the compression.
<font color="blue">243:</font>
<font color="blue">244:</font> If deflate returns with avail_out == 0, this function must be called again
<font color="blue">245:</font> with the same value of the flush parameter and more output space (updated
<font color="blue">246:</font> avail_out), until the flush is complete (deflate returns with non-zero
<font color="blue">247:</font> avail_out).
<font color="blue">248:</font>
<font color="blue">249:</font> If the parameter flush is set to Z_FINISH, pending input is processed,
<font color="blue">250:</font> pending output is flushed and deflate returns with Z_STREAM_END if there
<font color="blue">251:</font> was enough output space; if deflate returns with Z_OK, this function must be
<font color="blue">252:</font> called again with Z_FINISH and more output space (updated avail_out) but no
<font color="blue">253:</font> more input data, until it returns with Z_STREAM_END or an error. After
<font color="blue">254:</font> deflate has returned Z_STREAM_END, the only possible operations on the
<font color="blue">255:</font> stream are deflateReset or deflateEnd.
<font color="blue">256:</font>
<font color="blue">257:</font> Z_FINISH can be used immediately after deflateInit if all the compression
<font color="blue">258:</font> is to be done in a single step. In this case, avail_out must be at least
<font color="blue">259:</font> 0.1% larger than avail_in plus 12 bytes. If deflate does not return
<font color="blue">260:</font> Z_STREAM_END, then it must be called again as described above.
<font color="blue">261:</font>
<font color="blue">262:</font> deflate() sets strm->adler to the adler32 checksum of all input read
<font color="blue">263:</font> so far (that is, total_in bytes).
<font color="blue">264:</font>
<font color="blue">265:</font> deflate() may update data_type if it can make a good guess about
<font color="blue">266:</font> the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered
<font color="blue">267:</font> binary. This field is only for information purposes and does not affect
<font color="blue">268:</font> the compression algorithm in any manner.
<font color="blue">269:</font>
<font color="blue">270:</font> deflate() returns Z_OK if some progress has been made (more input
<font color="blue">271:</font> processed or more output produced), Z_STREAM_END if all input has been
<font color="blue">272:</font> consumed and all output has been produced (only when flush is set to
<font color="blue">273:</font> Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
<font color="blue">274:</font> if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible
<font color="blue">275:</font> (for example avail_in or avail_out was zero).
<font color="blue">276:</font> */
<font color="blue">277:</font>
<font color="blue">278:</font>
<font color="blue">279:</font> ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));
<font color="blue">280:</font> /*
<font color="blue">281:</font> All dynamically allocated data structures for this stream are freed.
<font color="blue">282:</font> This function discards any unprocessed input and does not flush any
<font color="blue">283:</font> pending output.
<font color="blue">284:</font>
<font color="blue">285:</font> deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
<font color="blue">286:</font> stream state was inconsistent, Z_DATA_ERROR if the stream was freed
<font color="blue">287:</font> prematurely (some input or output was discarded). In the error case,
<font color="blue">288:</font> msg may be set but then points to a static string (which must not be
<font color="blue">289:</font> deallocated).
<font color="blue">290:</font> */
<font color="blue">291:</font>
<font color="blue">292:</font>
<font color="blue">293:</font> /*
<font color="blue">294:</font> ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
<font color="blue">295:</font>
<font color="blue">296:</font> Initializes the internal stream state for decompression. The fields
<font color="blue">297:</font> next_in, avail_in, zalloc, zfree and opaque must be initialized before by
<font color="blue">298:</font> the caller. If next_in is not Z_NULL and avail_in is large enough (the exact
<font color="blue">299:</font> value depends on the compression method), inflateInit determines the
<font color="blue">300:</font> compression method from the zlib header and allocates all data structures
<font color="blue">301:</font> accordingly; otherwise the allocation will be deferred to the first call of
<font color="blue">302:</font> inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to
<font color="blue">303:</font> use default allocation functions.
<font color="blue">304:</font>
<font color="blue">305:</font> inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
<font color="blue">306:</font> memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
<font color="blue">307:</font> version assumed by the caller. msg is set to null if there is no error
<font color="blue">308:</font> message. inflateInit does not perform any decompression apart from reading
<font color="blue">309:</font> the zlib header if present: this will be done by inflate(). (So next_in and
<font color="blue">310:</font> avail_in may be modified, but next_out and avail_out are unchanged.)
<font color="blue">311:</font> */
<font color="blue">312:</font>
<font color="blue">313:</font>
<font color="blue">314:</font> ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
<font color="blue">315:</font> /*
<font color="blue">316:</font> inflate decompresses as much data as possible, and stops when the input
<font color="blue">317:</font> buffer becomes empty or the output buffer becomes full. It may some
<font color="blue">318:</font> introduce some output latency (reading input without producing any output)
<font color="blue">319:</font> except when forced to flush.
<font color="blue">320:</font>
<font color="blue">321:</font> The detailed semantics are as follows. inflate performs one or both of the
<font color="blue">322:</font> following actions:
<font color="blue">323:</font>
<font color="blue">324:</font> - Decompress more input starting at next_in and update next_in and avail_in
<font color="blue">325:</font> accordingly. If not all input can be processed (because there is not
<font color="blue">326:</font> enough room in the output buffer), next_in is updated and processing
<font color="blue">327:</font> will resume at this point for the next call of inflate().
<font color="blue">328:</font>
<font color="blue">329:</font> - Provide more output starting at next_out and update next_out and avail_out
<font color="blue">330:</font> accordingly. inflate() provides as much output as possible, until there
<font color="blue">331:</font> is no more input data or no more space in the output buffer (see below
<font color="blue">332:</font> about the flush parameter).
<font color="blue">333:</font>
<font color="blue">334:</font> Before the call of inflate(), the application should ensure that at least
<font color="blue">335:</font> one of the actions is possible, by providing more input and/or consuming
<font color="blue">336:</font> more output, and updating the next_* and avail_* values accordingly.
<font color="blue">337:</font> The application can consume the uncompressed output when it wants, for
<font color="blue">338:</font> example when the output buffer is full (avail_out == 0), or after each
<font color="blue">339:</font> call of inflate(). If inflate returns Z_OK and with zero avail_out, it
<font color="blue">340:</font> must be called again after making room in the output buffer because there
<font color="blue">341:</font> might be more output pending.
<font color="blue">342:</font>
<font color="blue">343:</font> If the parameter flush is set to Z_SYNC_FLUSH, inflate flushes as much
<font color="blue">344:</font> output as possible to the output buffer. The flushing behavior of inflate is
<font color="blue">345:</font> not specified for values of the flush parameter other than Z_SYNC_FLUSH
<font color="blue">346:</font> and Z_FINISH, but the current implementation actually flushes as much output
<font color="blue">347:</font> as possible anyway.
<font color="blue">348:</font>
<font color="blue">349:</font> inflate() should normally be called until it returns Z_STREAM_END or an
<font color="blue">350:</font> error. However if all decompression is to be performed in a single step
<font color="blue">351:</font> (a single call of inflate), the parameter flush should be set to
<font color="blue">352:</font> Z_FINISH. In this case all pending input is processed and all pending
<font color="blue">353:</font> output is flushed; avail_out must be large enough to hold all the
<font color="blue">354:</font> uncompressed data. (The size of the uncompressed data may have been saved
<font color="blue">355:</font> by the compressor for this purpose.) The next operation on this stream must
<font color="blue">356:</font> be inflateEnd to deallocate the decompression state. The use of Z_FINISH
<font color="blue">357:</font> is never required, but can be used to inform inflate that a faster routine
<font color="blue">358:</font> may be used for the single inflate() call.
<font color="blue">359:</font>
<font color="blue">360:</font> If a preset dictionary is needed at this point (see inflateSetDictionary
<font color="blue">361:</font> below), inflate sets strm-adler to the adler32 checksum of the
<font color="blue">362:</font> dictionary chosen by the compressor and returns Z_NEED_DICT; otherwise
<font color="blue">363:</font> it sets strm->adler to the adler32 checksum of all output produced
<font color="blue">364:</font> so far (that is, total_out bytes) and returns Z_OK, Z_STREAM_END or
<font color="blue">365:</font> an error code as described below. At the end of the stream, inflate()
<font color="blue">366:</font> checks that its computed adler32 checksum is equal to that saved by the
<font color="blue">367:</font> compressor and returns Z_STREAM_END only if the checksum is correct.
<font color="blue">368:</font>
<font color="blue">369:</font> inflate() returns Z_OK if some progress has been made (more input processed
<font color="blue">370:</font> or more output produced), Z_STREAM_END if the end of the compressed data has
<font color="blue">371:</font> been reached and all uncompressed output has been produced, Z_NEED_DICT if a
<font color="blue">372:</font> preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
<font color="blue">373:</font> corrupted (input stream not conforming to the zlib format or incorrect
<font color="blue">374:</font> adler32 checksum), Z_STREAM_ERROR if the stream structure was inconsistent
<font color="blue">375:</font> (for example if next_in or next_out was NULL), Z_MEM_ERROR if there was not
<font color="blue">376:</font> enough memory, Z_BUF_ERROR if no progress is possible or if there was not
<font color="blue">377:</font> enough room in the output buffer when Z_FINISH is used. In the Z_DATA_ERROR
<font color="blue">378:</font> case, the application may then call inflateSync to look for a good
<font color="blue">379:</font> compression block.
<font color="blue">380:</font> */
<font color="blue">381:</font>
<font color="blue">382:</font>
<font color="blue">383:</font> ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));
<font color="blue">384:</font> /*
<font color="blue">385:</font> All dynamically allocated data structures for this stream are freed.
<font color="blue">386:</font> This function discards any unprocessed input and does not flush any
<font color="blue">387:</font> pending output.
<font color="blue">388:</font>
<font color="blue">389:</font> inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
<font color="blue">390:</font> was inconsistent. In the error case, msg may be set but then points to a
<font color="blue">391:</font> static string (which must not be deallocated).
<font color="blue">392:</font> */
<font color="blue">393:</font>
<font color="blue">394:</font> /* Advanced functions */
<font color="blue">395:</font>
<font color="blue">396:</font> /*
<font color="blue">397:</font> The following functions are needed only in some special applications.
<font color="blue">398:</font> */
<font color="blue">399:</font>
<font color="blue">400:</font> /*
<font color="blue">401:</font> ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
<font color="blue">402:</font> int level,
<font color="blue">403:</font> int method,
<font color="blue">404:</font> int windowBits,
<font color="blue">405:</font> int memLevel,
<font color="blue">406:</font> int strategy));
<font color="blue">407:</font>
<font color="blue">408:</font> This is another version of deflateInit with more compression options. The
<font color="blue">409:</font> fields next_in, zalloc, zfree and opaque must be initialized before by
<font color="blue">410:</font> the caller.
<font color="blue">411:</font>
<font color="blue">412:</font> The method parameter is the compression method. It must be Z_DEFLATED in
<font color="blue">413:</font> this version of the library.
<font color="blue">414:</font>
<font color="blue">415:</font> The windowBits parameter is the base two logarithm of the window size
<font color="blue">416:</font> (the size of the history buffer). It should be in the range 8..15 for this
<font color="blue">417:</font> version of the library. Larger values of this parameter result in better
<font color="blue">418:</font> compression at the expense of memory usage. The default value is 15 if
<font color="blue">419:</font> deflateInit is used instead.
<font color="blue">420:</font>
<font color="blue">421:</font> The memLevel parameter specifies how much memory should be allocated
<font color="blue">422:</font> for the internal compression state. memLevel=1 uses minimum memory but
<font color="blue">423:</font> is slow and reduces compression ratio; memLevel=9 uses maximum memory
<font color="blue">424:</font> for optimal speed. The default value is 8. See zconf.h for total memory
<font color="blue">425:</font> usage as a function of windowBits and memLevel.
<font color="blue">426:</font>
<font color="blue">427:</font> The strategy parameter is used to tune the compression algorithm. Use the
<font color="blue">428:</font> value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
<font color="blue">429:</font> filter (or predictor), or Z_HUFFMAN_ONLY to force Huffman encoding only (no
<font color="blue">430:</font> string match). Filtered data consists mostly of small values with a
<font color="blue">431:</font> somewhat random distribution. In this case, the compression algorithm is
<font color="blue">432:</font> tuned to compress them better. The effect of Z_FILTERED is to force more
<font color="blue">433:</font> Huffman coding and less string matching; it is somewhat intermediate
<font color="blue">434:</font> between Z_DEFAULT and Z_HUFFMAN_ONLY. The strategy parameter only affects
<font color="blue">435:</font> the compression ratio but not the correctness of the compressed output even
<font color="blue">436:</font> if it is not set appropriately.
<font color="blue">437:</font>
<font color="blue">438:</font> deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
<font color="blue">439:</font> memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid
<font color="blue">440:</font> method). msg is set to null if there is no error message. deflateInit2 does
<font color="blue">441:</font> not perform any compression: this will be done by deflate().
<font color="blue">442:</font> */
<font color="blue">443:</font>
<font color="blue">444:</font> ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
<font color="blue">445:</font> const Bytef *dictionary,
<font color="blue">446:</font> uInt dictLength));
<font color="blue">447:</font> /*
<font color="blue">448:</font> Initializes the compression dictionary from the given byte sequence
<font color="blue">449:</font> without producing any compressed output. This function must be called
<font color="blue">450:</font> immediately after deflateInit, deflateInit2 or deflateReset, before any
<font color="blue">451:</font> call of deflate. The compressor and decompressor must use exactly the same
<font color="blue">452:</font> dictionary (see inflateSetDictionary).
<font color="blue">453:</font>
<font color="blue">454:</font> The dictionary should consist of strings (byte sequences) that are likely
<font color="blue">455:</font> to be encountered later in the data to be compressed, with the most commonly
<font color="blue">456:</font> used strings preferably put towards the end of the dictionary. Using a
<font color="blue">457:</font> dictionary is most useful when the data to be compressed is short and can be
<font color="blue">458:</font> predicted with good accuracy; the data can then be compressed better than
<font color="blue">459:</font> with the default empty dictionary.
<font color="blue">460:</font>
<font color="blue">461:</font> Depending on the size of the compression data structures selected by
<font color="blue">462:</font> deflateInit or deflateInit2, a part of the dictionary may in effect be
<font color="blue">463:</font> discarded, for example if the dictionary is larger than the window size in
<font color="blue">464:</font> deflate or deflate2. Thus the strings most likely to be useful should be
<font color="blue">465:</font> put at the end of the dictionary, not at the front.
<font color="blue">466:</font>
<font color="blue">467:</font> Upon return of this function, strm->adler is set to the Adler32 value
<font color="blue">468:</font> of the dictionary; the decompressor may later use this value to determine
<font color="blue">469:</font> which dictionary has been used by the compressor. (The Adler32 value
<font color="blue">470:</font> applies to the whole dictionary even if only a subset of the dictionary is
<font color="blue">471:</font> actually used by the compressor.)
<font color="blue">472:</font>
<font color="blue">473:</font> deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
<font color="blue">474:</font> parameter is invalid (such as NULL dictionary) or the stream state is
<font color="blue">475:</font> inconsistent (for example if deflate has already been called for this stream
<font color="blue">476:</font> or if the compression method is bsort). deflateSetDictionary does not
<font color="blue">477:</font> perform any compression: this will be done by deflate().
<font color="blue">478:</font> */
<font color="blue">479:</font>
<font color="blue">480:</font> ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,
<font color="blue">481:</font> z_streamp source));
<font color="blue">482:</font> /*
<font color="blue">483:</font> Sets the destination stream as a complete copy of the source stream.
<font color="blue">484:</font>
<font color="blue">485:</font> This function can be useful when several compression strategies will be
<font color="blue">486:</font> tried, for example when there are several ways of pre-processing the input
<font color="blue">487:</font> data with a filter. The streams that will be discarded should then be freed
<font color="blue">488:</font> by calling deflateEnd. Note that deflateCopy duplicates the internal
<font color="blue">489:</font> compression state which can be quite large, so this strategy is slow and
<font color="blue">490:</font> can consume lots of memory.
<font color="blue">491:</font>
<font color="blue">492:</font> deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
<font color="blue">493:</font> enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
<font color="blue">494:</font> (such as zalloc being NULL). msg is left unchanged in both source and
<font color="blue">495:</font> destination.
<font color="blue">496:</font> */
<font color="blue">497:</font>
<font color="blue">498:</font> ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));
<font color="blue">499:</font> /*
<font color="blue">500:</font> This function is equivalent to deflateEnd followed by deflateInit,
<font color="blue">501:</font> but does not free and reallocate all the internal compression state.
<font color="blue">502:</font> The stream will keep the same compression level and any other attributes
<font color="blue">503:</font> that may have been set by deflateInit2.
<font color="blue">504:</font>
<font color="blue">505:</font> deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
<font color="blue">506:</font> stream state was inconsistent (such as zalloc or state being NULL).
<font color="blue">507:</font> */
<font color="blue">508:</font>
<font color="blue">509:</font> ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,
<font color="blue">510:</font> int level,
<font color="blue">511:</font> int strategy));
<font color="blue">512:</font> /*
<font color="blue">513:</font> Dynamically update the compression level and compression strategy. The
<font color="blue">514:</font> interpretation of level and strategy is as in deflateInit2. This can be
<font color="blue">515:</font> used to switch between compression and straight copy of the input data, or
<font color="blue">516:</font> to switch to a different kind of input data requiring a different
<font color="blue">517:</font> strategy. If the compression level is changed, the input available so far
<font color="blue">518:</font> is compressed with the old level (and may be flushed); the new level will
<font color="blue">519:</font> take effect only at the next call of deflate().
<font color="blue">520:</font>
<font color="blue">521:</font> Before the call of deflateParams, the stream state must be set as for
<font color="blue">522:</font> a call of deflate(), since the currently available input may have to
<font color="blue">523:</font> be compressed and flushed. In particular, strm->avail_out must be non-zero.
<font color="blue">524:</font>
<font color="blue">525:</font> deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
<font color="blue">526:</font> stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR
<font color="blue">527:</font> if strm->avail_out was zero.
<font color="blue">528:</font> */
<font color="blue">529:</font>
<font color="blue">530:</font> /*
<font color="blue">531:</font> ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
<font color="blue">532:</font> int windowBits));
<font color="blue">533:</font>
<font color="blue">534:</font> This is another version of inflateInit with an extra parameter. The
<font color="blue">535:</font> fields next_in, avail_in, zalloc, zfree and opaque must be initialized
<font color="blue">536:</font> before by the caller.
<font color="blue">537:</font>
<font color="blue">538:</font> The windowBits parameter is the base two logarithm of the maximum window
<font color="blue">539:</font> size (the size of the history buffer). It should be in the range 8..15 for
<font color="blue">540:</font> this version of the library. The default value is 15 if inflateInit is used
<font color="blue">541:</font> instead. If a compressed stream with a larger window size is given as
<font color="blue">542:</font> input, inflate() will return with the error code Z_DATA_ERROR instead of
<font color="blue">543:</font> trying to allocate a larger window.
<font color="blue">544:</font>
<font color="blue">545:</font> inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
<font color="blue">546:</font> memory, Z_STREAM_ERROR if a parameter is invalid (such as a negative
<font color="blue">547:</font> memLevel). msg is set to null if there is no error message. inflateInit2
<font color="blue">548:</font> does not perform any decompression apart from reading the zlib header if
<font color="blue">549:</font> present: this will be done by inflate(). (So next_in and avail_in may be
<font color="blue">550:</font> modified, but next_out and avail_out are unchanged.)
<font color="blue">551:</font> */
<font color="blue">552:</font>
<font color="blue">553:</font> ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,
<font color="blue">554:</font> const Bytef *dictionary,
<font color="blue">555:</font> uInt dictLength));
<font color="blue">556:</font> /*
<font color="blue">557:</font> Initializes the decompression dictionary from the given uncompressed byte
<font color="blue">558:</font> sequence. This function must be called immediately after a call of inflate
<font color="blue">559:</font> if this call returned Z_NEED_DICT. The dictionary chosen by the compressor
<font color="blue">560:</font> can be determined from the Adler32 value returned by this call of
<font color="blue">561:</font> inflate. The compressor and decompressor must use exactly the same
<font color="blue">562:</font> dictionary (see deflateSetDictionary).
<font color="blue">563:</font>
<font color="blue">564:</font> inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
<font color="blue">565:</font> parameter is invalid (such as NULL dictionary) or the stream state is
<font color="blue">566:</font> inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
<font color="blue">567:</font> expected one (incorrect Adler32 value). inflateSetDictionary does not
<font color="blue">568:</font> perform any decompression: this will be done by subsequent calls of
<font color="blue">569:</font> inflate().
<font color="blue">570:</font> */
<font color="blue">571:</font>
<font color="blue">572:</font> ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));
<font color="blue">573:</font> /*
<font color="blue">574:</font> Skips invalid compressed data until a full flush point (see above the
<font color="blue">575:</font> description of deflate with Z_FULL_FLUSH) can be found, or until all
<font color="blue">576:</font> available input is skipped. No output is provided.
<font color="blue">577:</font>
<font color="blue">578:</font> inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR
<font color="blue">579:</font> if no more input was provided, Z_DATA_ERROR if no flush point has been found,
<font color="blue">580:</font> or Z_STREAM_ERROR if the stream structure was inconsistent. In the success
<font color="blue">581:</font> case, the application may save the current current value of total_in which
<font color="blue">582:</font> indicates where valid compressed data was found. In the error case, the
<font color="blue">583:</font> application may repeatedly call inflateSync, providing more input each time,
<font color="blue">584:</font> until success or end of the input data.
<font color="blue">585:</font> */
<font color="blue">586:</font>
<font color="blue">587:</font> ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));
<font color="blue">588:</font> /*
<font color="blue">589:</font> This function is equivalent to inflateEnd followed by inflateInit,
<font color="blue">590:</font> but does not free and reallocate all the internal decompression state.
<font color="blue">591:</font> The stream will keep attributes that may have been set by inflateInit2.
<font color="blue">592:</font>
<font color="blue">593:</font> inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
<font color="blue">594:</font> stream state was inconsistent (such as zalloc or state being NULL).
<font color="blue">595:</font> */
<font color="blue">596:</font>
<font color="blue">597:</font>
<font color="blue">598:</font> /* utility functions */
<font color="blue">599:</font>
<font color="blue">600:</font> /*
<font color="blue">601:</font> The following utility functions are implemented on top of the
<font color="blue">602:</font> basic stream-oriented functions. To simplify the interface, some
<font color="blue">603:</font> default options are assumed (compression level and memory usage,
<font color="blue">604:</font> standard memory allocation functions). The source code of these
<font color="blue">605:</font> utility functions can easily be modified if you need special options.
<font color="blue">606:</font> */
<font color="blue">607:</font>
<font color="blue">608:</font> ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen,
<font color="blue">609:</font> const Bytef *source, uLong sourceLen));
<font color="blue">610:</font> /*
<font color="blue">611:</font> Compresses the source buffer into the destination buffer. sourceLen is
<font color="blue">612:</font> the byte length of the source buffer. Upon entry, destLen is the total
<font color="blue">613:</font> size of the destination buffer, which must be at least 0.1% larger than
<font color="blue">614:</font> sourceLen plus 12 bytes. Upon exit, destLen is the actual size of the
<font color="blue">615:</font> compressed buffer.
<font color="blue">616:</font> This function can be used to compress a whole file at once if the
<font color="blue">617:</font> input file is mmap'ed.
<font color="blue">618:</font> compress returns Z_OK if success, Z_MEM_ERROR if there was not
<font color="blue">619:</font> enough memory, Z_BUF_ERROR if there was not enough room in the output
<font color="blue">620:</font> buffer.
<font color="blue">621:</font> */
<font color="blue">622:</font>
<font color="blue">623:</font> ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen,
<font color="blue">624:</font> const Bytef *source, uLong sourceLen,
<font color="blue">625:</font> int level));
<font color="blue">626:</font> /*
<font color="blue">627:</font> Compresses the source buffer into the destination buffer. The level
<font color="blue">628:</font> parameter has the same meaning as in deflateInit. sourceLen is the byte
<font color="blue">629:</font> length of the source buffer. Upon entry, destLen is the total size of the
<font color="blue">630:</font> destination buffer, which must be at least 0.1% larger than sourceLen plus
<font color="blue">631:</font> 12 bytes. Upon exit, destLen is the actual size of the compressed buffer.
<font color="blue">632:</font>
<font color="blue">633:</font> compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
<font color="blue">634:</font> memory, Z_BUF_ERROR if there was not enough room in the output buffer,
<font color="blue">635:</font> Z_STREAM_ERROR if the level parameter is invalid.
<font color="blue">636:</font> */
<font color="blue">637:</font>
<font color="blue">638:</font> ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen,
<font color="blue">639:</font> const Bytef *source, uLong sourceLen));
<font color="blue">640:</font> /*
<font color="blue">641:</font> Decompresses the source buffer into the destination buffer. sourceLen is
<font color="blue">642:</font> the byte length of the source buffer. Upon entry, destLen is the total
<font color="blue">643:</font> size of the destination buffer, which must be large enough to hold the
<font color="blue">644:</font> entire uncompressed data. (The size of the uncompressed data must have
<font color="blue">645:</font> been saved previously by the compressor and transmitted to the decompressor
<font color="blue">646:</font> by some mechanism outside the scope of this compression library.)
<font color="blue">647:</font> Upon exit, destLen is the actual size of the compressed buffer.
<font color="blue">648:</font> This function can be used to decompress a whole file at once if the
<font color="blue">649:</font> input file is mmap'ed.
<font color="blue">650:</font>
<font color="blue">651:</font> uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
<font color="blue">652:</font> enough memory, Z_BUF_ERROR if there was not enough room in the output
<font color="blue">653:</font> buffer, or Z_DATA_ERROR if the input data was corrupted.
<font color="blue">654:</font> */
<font color="blue">655:</font>
<font color="blue">656:</font>
<font color="blue">657:</font> typedef voidp gzFile;
<font color="blue">658:</font>
<font color="blue">659:</font> ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));
<font color="blue">660:</font> /*
<font color="blue">661:</font> Opens a gzip (.gz) file for reading or writing. The mode parameter
<font color="blue">662:</font> is as in fopen ("rb" or "wb") but can also include a compression level
<font color="blue">663:</font> ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for
<font color="blue">664:</font> Huffman only compression as in "wb1h". (See the description
<font color="blue">665:</font> of deflateInit2 for more information about the strategy parameter.)
<font color="blue">666:</font>
<font color="blue">667:</font> gzopen can be used to read a file which is not in gzip format; in this
<font color="blue">668:</font> case gzread will directly read from the file without decompression.
<font color="blue">669:</font>
<font color="blue">670:</font> gzopen returns NULL if the file could not be opened or if there was
<font color="blue">671:</font> insufficient memory to allocate the (de)compression state; errno
<font color="blue">672:</font> can be checked to distinguish the two cases (if errno is zero, the
<font color="blue">673:</font> zlib error is Z_MEM_ERROR). */
<font color="blue">674:</font>
<font color="blue">675:</font> ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode));
<font color="blue">676:</font> /*
<font color="blue">677:</font> gzdopen() associates a gzFile with the file descriptor fd. File
<font color="blue">678:</font> descriptors are obtained from calls like open, dup, creat, pipe or
<font color="blue">679:</font> fileno (in the file has been previously opened with fopen).
<font color="blue">680:</font> The mode parameter is as in gzopen.
<font color="blue">681:</font> The next call of gzclose on the returned gzFile will also close the
<font color="blue">682:</font> file descriptor fd, just like fclose(fdopen(fd), mode) closes the file
<font color="blue">683:</font> descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode).
<font color="blue">684:</font> gzdopen returns NULL if there was insufficient memory to allocate
<font color="blue">685:</font> the (de)compression state.
<font color="blue">686:</font> */
<font color="blue">687:</font>
<font color="blue">688:</font> ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
<font color="blue">689:</font> /*
<font color="blue">690:</font> Dynamically update the compression level or strategy. See the description
<font color="blue">691:</font> of deflateInit2 for the meaning of these parameters.
<font color="blue">692:</font> gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
<font color="blue">693:</font> opened for writing.
<font color="blue">694:</font> */
<font color="blue">695:</font>
<font color="blue">696:</font> ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));
<font color="blue">697:</font> /*
<font color="blue">698:</font> Reads the given number of uncompressed bytes from the compressed file.
<font color="blue">699:</font> If the input file was not in gzip format, gzread copies the given number
<font color="blue">700:</font> of bytes into the buffer.
<font color="blue">701:</font> gzread returns the number of uncompressed bytes actually read (0 for
<font color="blue">702:</font> end of file, -1 for error). */
<font color="blue">703:</font>
<font color="blue">704:</font> ZEXTERN int ZEXPORT gzwrite OF((gzFile file,
<font color="blue">705:</font> const voidp buf, unsigned len));
<font color="blue">706:</font> /*
<font color="blue">707:</font> Writes the given number of uncompressed bytes into the compressed file.
<font color="blue">708:</font> gzwrite returns the number of uncompressed bytes actually written
<font color="blue">709:</font> (0 in case of error).
<font color="blue">710:</font> */
<font color="blue">711:</font>
<font color="blue">712:</font> ZEXTERN int ZEXPORTVA gzprintf OF((gzFile file, const char *format, ...));
<font color="blue">713:</font> /*
<font color="blue">714:</font> Converts, formats, and writes the args to the compressed file under
<font color="blue">715:</font> control of the format string, as in fprintf. gzprintf returns the number of
<font color="blue">716:</font> uncompressed bytes actually written (0 in case of error).
<font color="blue">717:</font> */
<font color="blue">718:</font>
<font color="blue">719:</font> ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));
<font color="blue">720:</font> /*
<font color="blue">721:</font> Writes the given null-terminated string to the compressed file, excluding
<font color="blue">722:</font> the terminating null character.
<font color="blue">723:</font> gzputs returns the number of characters written, or -1 in case of error.
<font color="blue">724:</font> */
<font color="blue">725:</font>
<font color="blue">726:</font> ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));
<font color="blue">727:</font> /*
<font color="blue">728:</font> Reads bytes from the compressed file until len-1 characters are read, or
<font color="blue">729:</font> a newline character is read and transferred to buf, or an end-of-file
<font color="blue">730:</font> condition is encountered. The string is then terminated with a null
<font color="blue">731:</font> character.
<font color="blue">732:</font> gzgets returns buf, or Z_NULL in case of error.
<font color="blue">733:</font> */
<font color="blue">734:</font>
<font color="blue">735:</font> ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c));
<font color="blue">736:</font> /*
<font color="blue">737:</font> Writes c, converted to an unsigned char, into the compressed file.
<font color="blue">738:</font> gzputc returns the value that was written, or -1 in case of error.
<font color="blue">739:</font> */
<font color="blue">740:</font>
<font color="blue">741:</font> ZEXTERN int ZEXPORT gzgetc OF((gzFile file));
<font color="blue">742:</font> /*
<font color="blue">743:</font> Reads one byte from the compressed file. gzgetc returns this byte
<font color="blue">744:</font> or -1 in case of end of file or error.
<font color="blue">745:</font> */
<font color="blue">746:</font>
<font color="blue">747:</font> ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush));
<font color="blue">748:</font> /*
<font color="blue">749:</font> Flushes all pending output into the compressed file. The parameter
<font color="blue">750:</font> flush is as in the deflate() function. The return value is the zlib
<font color="blue">751:</font> error number (see function gzerror below). gzflush returns Z_OK if
<font color="blue">752:</font> the flush parameter is Z_FINISH and all output could be flushed.
<font color="blue">753:</font> gzflush should be called only when strictly necessary because it can
<font color="blue">754:</font> degrade compression.
<font color="blue">755:</font> */
<font color="blue">756:</font>
<font color="blue">757:</font> ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file,
<font color="blue">758:</font> z_off_t offset, int whence));
<font color="blue">759:</font> /*
<font color="blue">760:</font> Sets the starting position for the next gzread or gzwrite on the
<font color="blue">761:</font> given compressed file. The offset represents a number of bytes in the
<font color="blue">762:</font> uncompressed data stream. The whence parameter is defined as in lseek(2);
<font color="blue">763:</font> the value SEEK_END is not supported.
<font color="blue">764:</font> If the file is opened for reading, this function is emulated but can be
<font color="blue">765:</font> extremely slow. If the file is opened for writing, only forward seeks are
<font color="blue">766:</font> supported; gzseek then compresses a sequence of zeroes up to the new
<font color="blue">767:</font> starting position.
<font color="blue">768:</font>
<font color="blue">769:</font> gzseek returns the resulting offset location as measured in bytes from
<font color="blue">770:</font> the beginning of the uncompressed stream, or -1 in case of error, in
<font color="blue">771:</font> particular if the file is opened for writing and the new starting position
<font color="blue">772:</font> would be before the current position.
<font color="blue">773:</font> */
<font color="blue">774:</font>
<font color="blue">775:</font> ZEXTERN int ZEXPORT gzrewind OF((gzFile file));
<font color="blue">776:</font> /*
<font color="blue">777:</font> Rewinds the given file. This function is supported only for reading.
<font color="blue">778:</font>
<font color="blue">779:</font> gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
<font color="blue">780:</font> */
<font color="blue">781:</font>
<font color="blue">782:</font> ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file));
<font color="blue">783:</font> /*
<font color="blue">784:</font> Returns the starting position for the next gzread or gzwrite on the
<font color="blue">785:</font> given compressed file. This position represents a number of bytes in the
<font color="blue">786:</font> uncompressed data stream.
<font color="blue">787:</font>
<font color="blue">788:</font> gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
<font color="blue">789:</font> */
<font color="blue">790:</font>
<font color="blue">791:</font> ZEXTERN int ZEXPORT gzeof OF((gzFile file));
<font color="blue">792:</font> /*
<font color="blue">793:</font> Returns 1 when EOF has previously been detected reading the given
<font color="blue">794:</font> input stream, otherwise zero.
<font color="blue">795:</font> */
<font color="blue">796:</font>
<font color="blue">797:</font> ZEXTERN int ZEXPORT gzclose OF((gzFile file));
<font color="blue">798:</font> /*
<font color="blue">799:</font> Flushes all pending output if necessary, closes the compressed file
<font color="blue">800:</font> and deallocates all the (de)compression state. The return value is the zlib
<font color="blue">801:</font> error number (see function gzerror below).
<font color="blue">802:</font> */
<font color="blue">803:</font>
<font color="blue">804:</font> ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum));
<font color="blue">805:</font> /*
<font color="blue">806:</font> Returns the error message for the last error which occurred on the
<font color="blue">807:</font> given compressed file. errnum is set to zlib error number. If an
<font color="blue">808:</font> error occurred in the file system and not in the compression library,
<font color="blue">809:</font> errnum is set to Z_ERRNO and the application may consult errno
<font color="blue">810:</font> to get the exact error code.
<font color="blue">811:</font> */
<font color="blue">812:</font>
<font color="blue">813:</font> /* checksum functions */
<font color="blue">814:</font>
<font color="blue">815:</font> /*
<font color="blue">816:</font> These functions are not related to compression but are exported
<font color="blue">817:</font> anyway because they might be useful in applications using the
<font color="blue">818:</font> compression library.
<font color="blue">819:</font> */
<font color="blue">820:</font>
<font color="blue">821:</font> ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
<font color="blue">822:</font>
<font color="blue">823:</font> /*
<font color="blue">824:</font> Update a running Adler-32 checksum with the bytes buf[0..len-1] and
<font color="blue">825:</font> return the updated checksum. If buf is NULL, this function returns
<font color="blue">826:</font> the required initial value for the checksum.
<font color="blue">827:</font> An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
<font color="blue">828:</font> much faster. Usage example:
<font color="blue">829:</font>
<font color="blue">830:</font> uLong adler = adler32(0L, Z_NULL, 0);
<font color="blue">831:</font>
<font color="blue">832:</font> while (read_buffer(buffer, length) != EOF) {
<font color="blue">833:</font> adler = adler32(adler, buffer, length);
<font color="blue">834:</font> }
<font color="blue">835:</font> if (adler != original_adler) error();
<font color="blue">836:</font> */
<font color="blue">837:</font>
<font color="blue">838:</font> ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len));
<font color="blue">839:</font> /*
<font color="blue">840:</font> Update a running crc with the bytes buf[0..len-1] and return the updated
<font color="blue">841:</font> crc. If buf is NULL, this function returns the required initial value
<font color="blue">842:</font> for the crc. Pre- and post-conditioning (one's complement) is performed
<font color="blue">843:</font> within this function so it shouldn't be done by the application.
<font color="blue">844:</font> Usage example:
<font color="blue">845:</font>
<font color="blue">846:</font> uLong crc = crc32(0L, Z_NULL, 0);
<font color="blue">847:</font>
<font color="blue">848:</font> while (read_buffer(buffer, length) != EOF) {
<font color="blue">849:</font> crc = crc32(crc, buffer, length);
<font color="blue">850:</font> }
<font color="blue">851:</font> if (crc != original_crc) error();
<font color="blue">852:</font> */
<font color="blue">853:</font>
<font color="blue">854:</font>
<font color="blue">855:</font> /* various hacks, don't look :) */
<font color="blue">856:</font>
<font color="blue">857:</font> /* deflateInit and inflateInit are macros to allow checking the zlib version
<font color="blue">858:</font> * and the compiler's view of z_stream:
<font color="blue">859:</font> */
<font color="blue">860:</font> ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level,
<font color="blue">861:</font> const char *version, int stream_size));
<font color="blue">862:</font> ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm,
<font color="blue">863:</font> const char *version, int stream_size));
<font color="blue">864:</font> ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method,
<font color="blue">865:</font> int windowBits, int memLevel,
<font color="blue">866:</font> int strategy, const char *version,
<font color="blue">867:</font> int stream_size));
<font color="blue">868:</font> ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits,
<font color="blue">869:</font> const char *version, int stream_size));
<font color="blue"><a name="initmacros">870:</a></font> #define deflateInit(strm, level) \
<font color="blue">871:</font> deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream))
<font color="blue">872:</font> #define inflateInit(strm) \
<font color="blue">873:</font> inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream))
<font color="blue">874:</font> #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
<font color="blue">875:</font> deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
<font color="blue">876:</font> (strategy), ZLIB_VERSION, sizeof(z_stream))
<font color="blue">877:</font> #define inflateInit2(strm, windowBits) \
<font color="blue">878:</font> inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))
<font color="blue">879:</font>
<font color="blue">880:</font>
<font color="blue">881:</font> #if !defined(_Z_UTIL_H) && !defined(NO_DUMMY_DECL)
<font color="blue">882:</font> struct internal_state {int dummy;}; /* hack for buggy compilers */
<font color="blue">883:</font> #endif
<font color="blue">884:</font>
<font color="blue">885:</font> ZEXTERN const char * ZEXPORT zError OF((int err));
<font color="blue">886:</font> ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp z));
<font color="blue">887:</font> ZEXTERN const uLongf * ZEXPORT get_crc_table OF((void));
<font color="blue">888:</font>
<font color="blue">889:</font> #ifdef __cplusplus
<font color="blue">890:</font> }
<font color="blue">891:</font> #endif
<font color="blue">892:</font>
<font color="blue">893:</font> #endif /* _ZLIB_H */
</pre>
</blockquote>
<center><h2><a name="devel">How the zlib wrapper was developed</a></h2></center>
<h3>Attempt #1</h3>
<blockquote>
<pre>
/* File : example.i */
%module example
%{
/* Put headers and other declarations here */
#include "zlib.h"
%}
%include typemaps.i
%include "zlib.h"
</pre>
</blockquote>
The result is:
<blockquote>
<pre>
% swig -chicken -I/usr/include example.i
<a href="#l63">/usr/include/zlib.h:63</a>: Syntax error in input.
<a href="#l78">/usr/include/zlib.h:78</a>: Syntax error in input.
<a href="#l80">/usr/include/zlib.h:80</a>: Syntax error in input.
</pre>
</blockquote>
The first problem we see is that the macro <code>OF(...)</code> is
not defined.
<h3>Attempt #2</h3>
We make sure to include <tt>zconf.h</tt> so that SWIG can see the
definition of <code>OF(...)</code>. We try again.
<blockquote>
<pre>
/* File : example.i */
%module example
%{
/* Put headers and other declarations here */
#include "zlib.h"
%}
%include typemaps.i
<font color="red">%include "zconf.h"</font>
%include "zlib.h"
</pre>
</blockquote>
The result is:
<blockquote>
<pre>
% swig -chicken -I/usr/include example.i
</pre>
</blockquote>
This seems to work! But we should take a peek inside the generated
<tt>example_wrap.c</tt> to see what the names of the Scheme
procedures will be.
<blockquote>
<pre>
% grep C_intern example_wrap.c
C_word err = C_intern2 (&a, errorhook);
sym = C_intern (&a, 21, "example:max-mem-level");
sym = C_intern (&a, 17, "example:max-wbits");
sym = C_intern (&a, 16, "example:seek-set");
sym = C_intern (&a, 16, "example:seek-cur");
sym = C_intern (&a, 16, "example:seek-end");
sym = C_intern (&a, 20, "example:zlib-version");
sym = C_intern (&a, 28, "example:z-stream-next-in-set");
sym = C_intern (&a, 28, "example:z-stream-next-in-get");
sym = C_intern (&a, 29, "example:z-stream-avail-in-set");
sym = C_intern (&a, 29, "example:z-stream-avail-in-get");
sym = C_intern (&a, 29, "example:z-stream-total-in-set");
sym = C_intern (&a, 29, "example:z-stream-total-in-get");
sym = C_intern (&a, 29, "example:z-stream-next-out-set");
sym = C_intern (&a, 29, "example:z-stream-next-out-get");
sym = C_intern (&a, 30, "example:z-stream-avail-out-set");
sym = C_intern (&a, 30, "example:z-stream-avail-out-get");
sym = C_intern (&a, 30, "example:z-stream-total-out-set");
sym = C_intern (&a, 30, "example:z-stream-total-out-get");
sym = C_intern (&a, 24, "example:z-stream-msg-set");
sym = C_intern (&a, 24, "example:z-stream-msg-get");
sym = C_intern (&a, 26, "example:z-stream-state-set");
sym = C_intern (&a, 26, "example:z-stream-state-get");
sym = C_intern (&a, 27, "example:z-stream-zalloc-set");
sym = C_intern (&a, 27, "example:z-stream-zalloc-get");
sym = C_intern (&a, 26, "example:z-stream-zfree-set");
sym = C_intern (&a, 26, "example:z-stream-zfree-get");
sym = C_intern (&a, 27, "example:z-stream-opaque-set");
sym = C_intern (&a, 27, "example:z-stream-opaque-get");
sym = C_intern (&a, 30, "example:z-stream-data-type-set");
sym = C_intern (&a, 30, "example:z-stream-data-type-get");
sym = C_intern (&a, 26, "example:z-stream-adler-set");
sym = C_intern (&a, 26, "example:z-stream-adler-get");
sym = C_intern (&a, 29, "example:z-stream-reserved-set");
sym = C_intern (&a, 29, "example:z-stream-reserved-get");
sym = C_intern (&a, 20, "example:new-z-stream");
sym = C_intern (&a, 23, "example:delete-z-stream");
sym = C_intern (&a, 18, "example:z-no-flush");
sym = C_intern (&a, 23, "example:z-partial-flush");
sym = C_intern (&a, 20, "example:z-sync-flush");
sym = C_intern (&a, 20, "example:z-full-flush");
sym = C_intern (&a, 16, "example:z-finish");
sym = C_intern (&a, 12, "example:z-ok");
sym = C_intern (&a, 20, "example:z-stream-end");
sym = C_intern (&a, 19, "example:z-need-dict");
sym = C_intern (&a, 15, "example:z-errno");
sym = C_intern (&a, 22, "example:z-stream-error");
sym = C_intern (&a, 20, "example:z-data-error");
sym = C_intern (&a, 19, "example:z-mem-error");
sym = C_intern (&a, 19, "example:z-buf-error");
sym = C_intern (&a, 23, "example:z-version-error");
sym = C_intern (&a, 24, "example:z-no-compression");
sym = C_intern (&a, 20, "example:z-best-speed");
sym = C_intern (&a, 26, "example:z-best-compression");
sym = C_intern (&a, 29, "example:z-default-compression");
sym = C_intern (&a, 18, "example:z-filtered");
sym = C_intern (&a, 22, "example:z-huffman-only");
sym = C_intern (&a, 26, "example:z-default-strategy");
sym = C_intern (&a, 16, "example:z-binary");
sym = C_intern (&a, 15, "example:z-ascii");
sym = C_intern (&a, 17, "example:z-unknown");
sym = C_intern (&a, 18, "example:z-deflated");
sym = C_intern (&a, 14, "example:z-null");
sym = C_intern (&a, 19, "example:zlibversion");
sym = C_intern (&a, 15, "example:deflate");
sym = C_intern (&a, 18, "example:deflateend");
sym = C_intern (&a, 15, "example:inflate");
sym = C_intern (&a, 18, "example:inflateend");
sym = C_intern (&a, 28, "example:deflatesetdictionary");
sym = C_intern (&a, 19, "example:deflatecopy");
sym = C_intern (&a, 20, "example:deflatereset");
sym = C_intern (&a, 21, "example:deflateparams");
sym = C_intern (&a, 28, "example:inflatesetdictionary");
sym = C_intern (&a, 19, "example:inflatesync");
sym = C_intern (&a, 20, "example:inflatereset");
sym = C_intern (&a, 16, "example:compress");
sym = C_intern (&a, 17, "example:compress2");
sym = C_intern (&a, 18, "example:uncompress");
sym = C_intern (&a, 14, "example:gzopen");
sym = C_intern (&a, 15, "example:gzdopen");
sym = C_intern (&a, 19, "example:gzsetparams");
sym = C_intern (&a, 14, "example:gzread");
sym = C_intern (&a, 15, "example:gzwrite");
sym = C_intern (&a, 16, "example:gzprintf");
sym = C_intern (&a, 14, "example:gzputs");
sym = C_intern (&a, 14, "example:gzgets");
sym = C_intern (&a, 14, "example:gzputc");
sym = C_intern (&a, 14, "example:gzgetc");
sym = C_intern (&a, 15, "example:gzflush");
sym = C_intern (&a, 14, "example:gzseek");
sym = C_intern (&a, 16, "example:gzrewind");
sym = C_intern (&a, 14, "example:gztell");
sym = C_intern (&a, 13, "example:gzeof");
sym = C_intern (&a, 15, "example:gzclose");
sym = C_intern (&a, 15, "example:gzerror");
sym = C_intern (&a, 15, "example:adler32");
sym = C_intern (&a, 13, "example:crc32");
sym = C_intern (&a, 20, "example:deflateinit-");
sym = C_intern (&a, 20, "example:inflateinit-");
sym = C_intern (&a, 21, "example:deflateinit2-");
sym = C_intern (&a, 21, "example:inflateinit2-");
sym = C_intern (&a, 32, "example:internal-state-dummy-set");
sym = C_intern (&a, 32, "example:internal-state-dummy-get");
sym = C_intern (&a, 26, "example:new-internal-state");
sym = C_intern (&a, 29, "example:delete-internal-state");
sym = C_intern (&a, 14, "example:zerror");
sym = C_intern (&a, 24, "example:inflatesyncpoint");
sym = C_intern (&a, 21, "example:get-crc-table");
</pre>
</blockquote>
In fact, we want the Scheme procedure names to begin with
<code>zlib</code> instead of <code>example</code>. For
<code>example:zlib-version</code>, we want
<code>zlib-version</code>. And we want dashes when the case
switches to/from upper/lowercase; ex. the function
<code>deflateEnd()</code> should be the Scheme procedure
<code>zlib-deflate-end</code>.
<h3>Attempt #3</h3>
We make sure to add <tt>-prefix zlib -mixed</tt> to the
<tt>swig</tt> command line, and we rename
<code>ZLIB_VERSION</code> to <code>VERSION</code>. We try again.
<blockquote>
<pre>
/* File : example.i */
%module example
%{
/* Put headers and other declarations here */
#include "zlib.h"
%}
%include typemaps.i
<font color="red">%rename(VERSION) ZLIB_VERSION;</font>
%include "zconf.h"
%include "zlib.h"
</pre>
</blockquote>
The result is:
<blockquote>
<pre>
% swig -chicken <font color="red">-prefix zlib -mixed</font> -I/usr/include example.i
% grep C_intern example_wrap.c
C_word err = C_intern2 (&a, errorhook);
sym = C_intern (&a, 18, "zlib:max-mem-level");
sym = C_intern (&a, 14, "zlib:max-wbits");
sym = C_intern (&a, 13, "zlib:seek-set");
sym = C_intern (&a, 13, "zlib:seek-cur");
sym = C_intern (&a, 13, "zlib:seek-end");
sym = C_intern (&a, 12, "zlib:version");
sym = C_intern (&a, 25, "zlib:z-stream-next-in-set");
sym = C_intern (&a, 25, "zlib:z-stream-next-in-get");
sym = C_intern (&a, 26, "zlib:z-stream-avail-in-set");
sym = C_intern (&a, 26, "zlib:z-stream-avail-in-get");
sym = C_intern (&a, 26, "zlib:z-stream-total-in-set");
sym = C_intern (&a, 26, "zlib:z-stream-total-in-get");
sym = C_intern (&a, 26, "zlib:z-stream-next-out-set");
sym = C_intern (&a, 26, "zlib:z-stream-next-out-get");
sym = C_intern (&a, 27, "zlib:z-stream-avail-out-set");
sym = C_intern (&a, 27, "zlib:z-stream-avail-out-get");
sym = C_intern (&a, 27, "zlib:z-stream-total-out-set");
sym = C_intern (&a, 27, "zlib:z-stream-total-out-get");
sym = C_intern (&a, 21, "zlib:z-stream-msg-set");
sym = C_intern (&a, 21, "zlib:z-stream-msg-get");
sym = C_intern (&a, 23, "zlib:z-stream-state-set");
sym = C_intern (&a, 23, "zlib:z-stream-state-get");
sym = C_intern (&a, 24, "zlib:z-stream-zalloc-set");
sym = C_intern (&a, 24, "zlib:z-stream-zalloc-get");
sym = C_intern (&a, 23, "zlib:z-stream-zfree-set");
sym = C_intern (&a, 23, "zlib:z-stream-zfree-get");
sym = C_intern (&a, 24, "zlib:z-stream-opaque-set");
sym = C_intern (&a, 24, "zlib:z-stream-opaque-get");
sym = C_intern (&a, 27, "zlib:z-stream-data-type-set");
sym = C_intern (&a, 27, "zlib:z-stream-data-type-get");
sym = C_intern (&a, 23, "zlib:z-stream-adler-set");
sym = C_intern (&a, 23, "zlib:z-stream-adler-get");
sym = C_intern (&a, 26, "zlib:z-stream-reserved-set");
sym = C_intern (&a, 26, "zlib:z-stream-reserved-get");
sym = C_intern (&a, 17, "zlib:new-z-stream");
sym = C_intern (&a, 20, "zlib:delete-z-stream");
sym = C_intern (&a, 15, "zlib:z-no-flush");
sym = C_intern (&a, 20, "zlib:z-partial-flush");
sym = C_intern (&a, 17, "zlib:z-sync-flush");
sym = C_intern (&a, 17, "zlib:z-full-flush");
sym = C_intern (&a, 13, "zlib:z-finish");
sym = C_intern (&a, 9, "zlib:z-ok");
sym = C_intern (&a, 17, "zlib:z-stream-end");
sym = C_intern (&a, 16, "zlib:z-need-dict");
sym = C_intern (&a, 12, "zlib:z-errno");
sym = C_intern (&a, 19, "zlib:z-stream-error");
sym = C_intern (&a, 17, "zlib:z-data-error");
sym = C_intern (&a, 16, "zlib:z-mem-error");
sym = C_intern (&a, 16, "zlib:z-buf-error");
sym = C_intern (&a, 20, "zlib:z-version-error");
sym = C_intern (&a, 21, "zlib:z-no-compression");
sym = C_intern (&a, 17, "zlib:z-best-speed");
sym = C_intern (&a, 23, "zlib:z-best-compression");
sym = C_intern (&a, 26, "zlib:z-default-compression");
sym = C_intern (&a, 15, "zlib:z-filtered");
sym = C_intern (&a, 19, "zlib:z-huffman-only");
sym = C_intern (&a, 23, "zlib:z-default-strategy");
sym = C_intern (&a, 13, "zlib:z-binary");
sym = C_intern (&a, 12, "zlib:z-ascii");
sym = C_intern (&a, 14, "zlib:z-unknown");
sym = C_intern (&a, 15, "zlib:z-deflated");
sym = C_intern (&a, 11, "zlib:z-null");
sym = C_intern (&a, 17, "zlib:zlib-version");
sym = C_intern (&a, 12, "zlib:deflate");
sym = C_intern (&a, 16, "zlib:deflate-end");
sym = C_intern (&a, 12, "zlib:inflate");
sym = C_intern (&a, 16, "zlib:inflate-end");
sym = C_intern (&a, 27, "zlib:deflate-set-dictionary");
sym = C_intern (&a, 17, "zlib:deflate-copy");
sym = C_intern (&a, 18, "zlib:deflate-reset");
sym = C_intern (&a, 19, "zlib:deflate-params");
sym = C_intern (&a, 27, "zlib:inflate-set-dictionary");
sym = C_intern (&a, 17, "zlib:inflate-sync");
sym = C_intern (&a, 18, "zlib:inflate-reset");
sym = C_intern (&a, 13, "zlib:compress");
sym = C_intern (&a, 14, "zlib:compress2");
sym = C_intern (&a, 15, "zlib:uncompress");
sym = C_intern (&a, 11, "zlib:gzopen");
sym = C_intern (&a, 12, "zlib:gzdopen");
sym = C_intern (&a, 16, "zlib:gzsetparams");
sym = C_intern (&a, 11, "zlib:gzread");
sym = C_intern (&a, 12, "zlib:gzwrite");
sym = C_intern (&a, 13, "zlib:gzprintf");
sym = C_intern (&a, 11, "zlib:gzputs");
sym = C_intern (&a, 11, "zlib:gzgets");
sym = C_intern (&a, 11, "zlib:gzputc");
sym = C_intern (&a, 11, "zlib:gzgetc");
sym = C_intern (&a, 12, "zlib:gzflush");
sym = C_intern (&a, 11, "zlib:gzseek");
sym = C_intern (&a, 13, "zlib:gzrewind");
sym = C_intern (&a, 11, "zlib:gztell");
sym = C_intern (&a, 10, "zlib:gzeof");
sym = C_intern (&a, 12, "zlib:gzclose");
sym = C_intern (&a, 12, "zlib:gzerror");
sym = C_intern (&a, 12, "zlib:adler32");
sym = C_intern (&a, 10, "zlib:crc32");
sym = C_intern (&a, 18, "zlib:deflate-init-");
sym = C_intern (&a, 18, "zlib:inflate-init-");
sym = C_intern (&a, 19, "zlib:deflate-init2-");
sym = C_intern (&a, 19, "zlib:inflate-init2-");
sym = C_intern (&a, 29, "zlib:internal-state-dummy-set");
sym = C_intern (&a, 29, "zlib:internal-state-dummy-get");
sym = C_intern (&a, 23, "zlib:new-internal-state");
sym = C_intern (&a, 26, "zlib:delete-internal-state");
sym = C_intern (&a, 12, "zlib:ze-rror");
sym = C_intern (&a, 23, "zlib:inflate-sync-point");
sym = C_intern (&a, 18, "zlib:get-crc-table");
</pre>
</blockquote>
Much better. The only problem is the identifier
<code>zlib:ze-rror</code>, and we are missing
<code>zlib:deflate-init</code> and <code>zlib:inflate-init</code>
because they are defined as macros (see <a
href="#initmacros">macro definitions</a>).
<h3>Attempt #4</h3>
We make sure to rename <code>zError</code> to
<code>z_error</code>, and we inline some helper functions for the
<code>zlib:...-init</code> macros. We try again.
<blockquote>
<pre>
/* File : example.i */
%module example
%{
/* Put headers and other declarations here */
#include "zlib.h"
%}
%include typemaps.i
%rename(VERSION) ZLIB_VERSION;
<font color="red">%rename(z_error) zError;</font>
%include "zconf.h"
%include "zlib.h"
<font color="red">%inline %{
/* %inline blocks are seen by SWIG and are inserted into the header
portion of example_wrap.c, so that they are also seen by the C
compiler. */
int deflate_init(z_streamp strm, int level) {
return deflateInit(strm,level); /* call macro */
}
int inflate_init(z_streamp strm) {
return inflateInit(strm); /* call macro */
}
%}
</font>
</pre>
</blockquote>
The result is:
<blockquote>
<pre>
% swig -chicken -prefix zlib -mixed -I/usr/include example.i
% grep C_intern example_wrap.c
C_word err = C_intern2 (&a, errorhook);
sym = C_intern (&a, 18, "zlib:max-mem-level");
sym = C_intern (&a, 14, "zlib:max-wbits");
sym = C_intern (&a, 13, "zlib:seek-set");
sym = C_intern (&a, 13, "zlib:seek-cur");
sym = C_intern (&a, 13, "zlib:seek-end");
sym = C_intern (&a, 12, "zlib:version");
sym = C_intern (&a, 25, "zlib:z-stream-next-in-set");
sym = C_intern (&a, 25, "zlib:z-stream-next-in-get");
sym = C_intern (&a, 26, "zlib:z-stream-avail-in-set");
sym = C_intern (&a, 26, "zlib:z-stream-avail-in-get");
sym = C_intern (&a, 26, "zlib:z-stream-total-in-set");
sym = C_intern (&a, 26, "zlib:z-stream-total-in-get");
sym = C_intern (&a, 26, "zlib:z-stream-next-out-set");
sym = C_intern (&a, 26, "zlib:z-stream-next-out-get");
sym = C_intern (&a, 27, "zlib:z-stream-avail-out-set");
sym = C_intern (&a, 27, "zlib:z-stream-avail-out-get");
sym = C_intern (&a, 27, "zlib:z-stream-total-out-set");
sym = C_intern (&a, 27, "zlib:z-stream-total-out-get");
sym = C_intern (&a, 21, "zlib:z-stream-msg-set");
sym = C_intern (&a, 21, "zlib:z-stream-msg-get");
sym = C_intern (&a, 23, "zlib:z-stream-state-set");
sym = C_intern (&a, 23, "zlib:z-stream-state-get");
sym = C_intern (&a, 24, "zlib:z-stream-zalloc-set");
sym = C_intern (&a, 24, "zlib:z-stream-zalloc-get");
sym = C_intern (&a, 23, "zlib:z-stream-zfree-set");
sym = C_intern (&a, 23, "zlib:z-stream-zfree-get");
sym = C_intern (&a, 24, "zlib:z-stream-opaque-set");
sym = C_intern (&a, 24, "zlib:z-stream-opaque-get");
sym = C_intern (&a, 27, "zlib:z-stream-data-type-set");
sym = C_intern (&a, 27, "zlib:z-stream-data-type-get");
sym = C_intern (&a, 23, "zlib:z-stream-adler-set");
sym = C_intern (&a, 23, "zlib:z-stream-adler-get");
sym = C_intern (&a, 26, "zlib:z-stream-reserved-set");
sym = C_intern (&a, 26, "zlib:z-stream-reserved-get");
sym = C_intern (&a, 17, "zlib:new-z-stream");
sym = C_intern (&a, 20, "zlib:delete-z-stream");
sym = C_intern (&a, 15, "zlib:z-no-flush");
sym = C_intern (&a, 20, "zlib:z-partial-flush");
sym = C_intern (&a, 17, "zlib:z-sync-flush");
sym = C_intern (&a, 17, "zlib:z-full-flush");
sym = C_intern (&a, 13, "zlib:z-finish");
sym = C_intern (&a, 9, "zlib:z-ok");
sym = C_intern (&a, 17, "zlib:z-stream-end");
sym = C_intern (&a, 16, "zlib:z-need-dict");
sym = C_intern (&a, 12, "zlib:z-errno");
sym = C_intern (&a, 19, "zlib:z-stream-error");
sym = C_intern (&a, 17, "zlib:z-data-error");
sym = C_intern (&a, 16, "zlib:z-mem-error");
sym = C_intern (&a, 16, "zlib:z-buf-error");
sym = C_intern (&a, 20, "zlib:z-version-error");
sym = C_intern (&a, 21, "zlib:z-no-compression");
sym = C_intern (&a, 17, "zlib:z-best-speed");
sym = C_intern (&a, 23, "zlib:z-best-compression");
sym = C_intern (&a, 26, "zlib:z-default-compression");
sym = C_intern (&a, 15, "zlib:z-filtered");
sym = C_intern (&a, 19, "zlib:z-huffman-only");
sym = C_intern (&a, 23, "zlib:z-default-strategy");
sym = C_intern (&a, 13, "zlib:z-binary");
sym = C_intern (&a, 12, "zlib:z-ascii");
sym = C_intern (&a, 14, "zlib:z-unknown");
sym = C_intern (&a, 15, "zlib:z-deflated");
sym = C_intern (&a, 11, "zlib:z-null");
sym = C_intern (&a, 17, "zlib:zlib-version");
sym = C_intern (&a, 12, "zlib:deflate");
sym = C_intern (&a, 16, "zlib:deflate-end");
sym = C_intern (&a, 12, "zlib:inflate");
sym = C_intern (&a, 16, "zlib:inflate-end");
sym = C_intern (&a, 27, "zlib:deflate-set-dictionary");
sym = C_intern (&a, 17, "zlib:deflate-copy");
sym = C_intern (&a, 18, "zlib:deflate-reset");
sym = C_intern (&a, 19, "zlib:deflate-params");
sym = C_intern (&a, 27, "zlib:inflate-set-dictionary");
sym = C_intern (&a, 17, "zlib:inflate-sync");
sym = C_intern (&a, 18, "zlib:inflate-reset");
sym = C_intern (&a, 13, "zlib:compress");
sym = C_intern (&a, 14, "zlib:compress2");
sym = C_intern (&a, 15, "zlib:uncompress");
sym = C_intern (&a, 11, "zlib:gzopen");
sym = C_intern (&a, 12, "zlib:gzdopen");
sym = C_intern (&a, 16, "zlib:gzsetparams");
sym = C_intern (&a, 11, "zlib:gzread");
sym = C_intern (&a, 12, "zlib:gzwrite");
sym = C_intern (&a, 13, "zlib:gzprintf");
sym = C_intern (&a, 11, "zlib:gzputs");
sym = C_intern (&a, 11, "zlib:gzgets");
sym = C_intern (&a, 11, "zlib:gzputc");
sym = C_intern (&a, 11, "zlib:gzgetc");
sym = C_intern (&a, 12, "zlib:gzflush");
sym = C_intern (&a, 11, "zlib:gzseek");
sym = C_intern (&a, 13, "zlib:gzrewind");
sym = C_intern (&a, 11, "zlib:gztell");
sym = C_intern (&a, 10, "zlib:gzeof");
sym = C_intern (&a, 12, "zlib:gzclose");
sym = C_intern (&a, 12, "zlib:gzerror");
sym = C_intern (&a, 12, "zlib:adler32");
sym = C_intern (&a, 10, "zlib:crc32");
sym = C_intern (&a, 18, "zlib:deflate-init-");
sym = C_intern (&a, 18, "zlib:inflate-init-");
sym = C_intern (&a, 19, "zlib:deflate-init2-");
sym = C_intern (&a, 19, "zlib:inflate-init2-");
sym = C_intern (&a, 29, "zlib:internal-state-dummy-set");
sym = C_intern (&a, 29, "zlib:internal-state-dummy-get");
sym = C_intern (&a, 23, "zlib:new-internal-state");
sym = C_intern (&a, 26, "zlib:delete-internal-state");
sym = C_intern (&a, 12, "zlib:z-error");
sym = C_intern (&a, 23, "zlib:inflate-sync-point");
sym = C_intern (&a, 18, "zlib:get-crc-table");
sym = C_intern (&a, 17, "zlib:deflate-init");
sym = C_intern (&a, 17, "zlib:inflate-init");
</pre>
</blockquote>
Perfect! Now let's integrate this zlib extension into a
CHICKEN interpreter. To save some time, in this
Examples/chicken/zlib directory:
<ol>
<li>Backup the original <tt>example.i</tt>.</li>
<li>Copy and paste the <tt>example.i</tt> text from above and
put it into the file called <tt>example.i</tt></li>
<li>Run 'make' as per <a href="#build">Building the
example</a>.</li>
<li>Run the resultant executable <tt>zlib</tt>.</li>
</ol>
The interpreter interaction is as follows:
<blockquote>
<pre>
% ./zlib
zlib
A SWIG example for the CHICKEN compiler
Author: Jonah Beckford, February 2003
Scheme Procedures:
zlib:max-mem-level
zlib:max-wbits
zlib:seek-set
zlib:seek-cur
zlib:seek-end
zlib:version
zlib:z-stream-next-in-set
zlib:z-stream-next-in-get
zlib:z-stream-avail-in-set
...
zlib:get-crc-table
zlib:deflate-init
zlib:inflate-init
; This is the CHICKEN interpreter - Version 0, Build 1095 - windows-cygwin-x86
; (c)2000-2003 Felix L. Winkelmann
>>> (define s (zlib:new-z-stream))
>>> s
#<tagged pointer #<c++ "z_stream *">(#<pointer 6d9290>)>
>>> (zlib:z-stream-next-in-get s)
#f
>>> (zlib:z-stream-next-in-set s "some dummy stream data")
Error: Type error. Expected _p_Bytef: "bad argument type"
>>> (exit)
</pre>
</blockquote>
Apparently we cannot use Scheme strings as <code>Bytef *</code>. The SWIG
manual shows many ways how to handle strings and byte arrays, but
to be simplistic, let's just make the <code>Bytef *</code> look
like a <code>char *</code>, which is automatically handled as a
string by SWIG CHICKEN.
<h3>Attempt #5</h3>
We make sure to add an %apply construct so that <code>Bytef
*</code> is handled the same as <code>char *</code> to SWIG. We
try again.
<blockquote>
<pre>
/* File : example.i */
%module example
%{
/* Put headers and other declarations here */
#include "zlib.h"
%}
%include typemaps.i
%rename(VERSION) ZLIB_VERSION;
%rename(z_error) zError;
<font color="red">%apply char * { Bytef * };</font>
%include "zconf.h"
%include "zlib.h"
%inline %{
/* %inline blocks are seen by SWIG and are inserted into the header
portion of example_wrap.c, so that they are also seen by the C
compiler. */
int deflate_init(z_streamp strm, int level) {
return deflateInit(strm,level); /* call macro */
}
int inflate_init(z_streamp strm) {
return inflateInit(strm); /* call macro */
}
%}
</pre>
</blockquote>
Build the example once more.<br>
The interpreter interaction is as follows:
<blockquote>
<pre>
% ./zlib
zlib
A SWIG example for the CHICKEN compiler
Author: Jonah Beckford, February 2003
Scheme Procedures:
zlib:max-mem-level
zlib:max-wbits
zlib:seek-set
zlib:seek-cur
zlib:seek-end
zlib:version
zlib:z-stream-next-in-set
zlib:z-stream-next-in-get
zlib:z-stream-avail-in-set
...
zlib:get-crc-table
zlib:deflate-init
zlib:inflate-init
; This is the CHICKEN interpreter - Version 0, Build 1095 - windows-cygwin-x86
; (c)2000-2003 Felix L. Winkelmann
>>> (define s (zlib:new-z-stream))
<em>Init zstream</em>
>>> (zlib:z-stream-zalloc-set s #f)
>>> (zlib:z-stream-zfree-set s #f)
>>> (zlib:z-stream-opaque-set s #f)
>>> (zlib:deflate-init s (zlib:z-default-compression))
0
<em>Deflate something small so we don't need to loop/stream data</em>
>>> (define in "some dummy data")
>>> (define out (make-string 1000))
>>> (zlib:z-stream-next-in-set s in)
>>> (zlib:z-stream-avail-in-set s (string-length in))
>>> (zlib:z-stream-next-out-set s out)
>>> (zlib:z-stream-avail-out-set s (string-length out))
>>> (zlib:deflate s (zlib:z-finish))
1 <em>;; (zlib:z-stream-end) == 1, which is good</em>
>>> (zlib:z-stream-total-out-get s)
23.
>>> out
" "
</pre>
</blockquote>
We see the problem ... the compression is occurring as it should,
but we cannot see any of the compressed output. This is because
when SWIG CHICKEN passes a Scheme string to a C function, it
duplicates the string before calling the C function. We want to
save the memory address that
<code>zlib:z-stream-next-out-set</code> is using, so we can
display this later. While we are at it, we can foresee that
<code>compress</code>, <code>compress2</code> and
<code>uncompress</code> will all need some finessing to work with
mutating strings.
<h3>Attempt #6</h3>
When we have to finesse strings, we must use typemaps. As well,
we define some functions to save and restore the
<code>next_out</code> element. We try again.
<blockquote>
<pre>
/* File : example.i */
%module example
%{
/* Put headers and other declarations here */
#include "zlib.h"
%}
%include typemaps.i
%rename(VERSION) ZLIB_VERSION;
%rename(z_error) zError;
%apply char * { Bytef * };
<font color="red">
/* Allow the sourceLen to be automatically filled in from the length
of the 'source' string */
%typemap(in) (const Bytef *source, uLong sourceLen)
%{ if (!C_swig_is_string ($input)) {
swig_barf (SWIG_BARF1_BAD_ARGUMENT_TYPE, "Argument $input is not a string");
}
$2 = (uLong) C_header_size ($input);
$1 = C_c_string ($input);
%}
/* Allocate space the size of which is determined by the Scheme
integer argument, and make a temporary integer so we can set
destLen. */
%typemap(in) (Bytef *dest, uLongf *destLen) (uLong len)
%{ if (!C_swig_is_fixnum ($input)) {
swig_barf (SWIG_BARF1_BAD_ARGUMENT_TYPE, "Argument $input is not a integer");
}
len = (uLong) C_unfix ($input);
$2 = &len;
$1 = (char *) malloc (*$2);
%}
/* Return the mutated string as a new object. */
%typemap(argout) (Bytef *dest, uLongf *destLen)
(C_word *scmstr)
%{ scmstr = C_alloc (C_SIZEOF_STRING (*$2));
SWIG_APPEND_VALUE(C_string (&scmstr, *$2, $1));
free ($1);
%}
</font>
%include "zconf.h"
%include "zlib.h"
<font color="red">
/* Ignore destLen as an input argument, and make a temporary integer so
we can set destLen. */
%typemap(in, numinputs=0) uLongf *destLen (uLong len)
"$1 = &len;";
/* Return a sized string as a new object. */
%typemap(argout)
(void *outstr, uLongf *destLen) (C_word *scmstr)
%{ scmstr = C_alloc (C_SIZEOF_STRING (*$2));
SWIG_APPEND_VALUE(C_string (&scmstr, *$2, $1));
%}
</font>
%inline %{
/* %inline blocks are seen by SWIG and are inserted into the header
portion of example_wrap.c, so that they are also seen by the C
compiler. */
int deflate_init(z_streamp strm, int level) {
return deflateInit(strm,level); /* call macro */
}
int inflate_init(z_streamp strm) {
return inflateInit(strm); /* call macro */
}
<font color="red">void* z_stream_save_next_out(z_streamp strm) {
return (void*) strm->next_out;
}
void z_stream_get_next_chunk(z_streamp strm, void *outstr, uLongf *destLen) {
*destLen = strm->next_out - (Bytef*)outstr;
}</font>
%}
</pre>
</blockquote>
And that's it. Try building the entire example from the
Makefile. Run <tt>./zlib test-zlib.scm</tt> to test it out.
</body>
</html>
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