CbC/CbC_gcc: zlib/examples/zlib

annotate zlib/examples/zlib_how.html @ 51:ae3a4bfb450b

add some files of version 4.4.3 that have been forgotten.

author	kent <kent@cr.ie.u-ryukyu.ac.jp>
date	Sun, 07 Feb 2010 18:27:48 +0900
parents
children	04ced10e8804

rev	line source
51 ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	1 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	2 "http://www.w3.org/TR/REC-html40/loose.dtd">
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	3 <html>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	4 <head>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	5 <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	6 <title>zlib Usage Example</title>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	7 <!-- Copyright (c) 2004 Mark Adler. -->
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	8 </head>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	9 <body bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#00A000">
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	10 <h2 align="center"> zlib Usage Example </h2>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	11 We often get questions about how the <tt>deflate()</tt> and <tt>inflate()</tt> functions should be used.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	12 Users wonder when they should provide more input, when they should use more output,
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	13 what to do with a <tt>Z_BUF_ERROR</tt>, how to make sure the process terminates properly, and
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	14 so on. So for those who have read <tt>zlib.h</tt> (a few times), and
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	15 would like further edification, below is an annotated example in C of simple routines to compress and decompress
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	16 from an input file to an output file using <tt>deflate()</tt> and <tt>inflate()</tt> respectively. The
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	17 annotations are interspersed between lines of the code. So please read between the lines.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	18 We hope this helps explain some of the intricacies of <em>zlib</em>.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	19 <p>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	20 Without further adieu, here is the program <a href="zpipe.c"><tt>zpipe.c</tt></a>:
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	21 <pre><b>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	22 /* zpipe.c: example of proper use of zlib's inflate() and deflate()
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	23 Not copyrighted -- provided to the public domain
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	24 Version 1.2 9 November 2004 Mark Adler */
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	25
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	26 /* Version history:
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	27 1.0 30 Oct 2004 First version
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	28 1.1 8 Nov 2004 Add void casting for unused return values
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	29 Use switch statement for inflate() return values
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	30 1.2 9 Nov 2004 Add assertions to document zlib guarantees
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	31 */
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	32 </b></pre><!-- -->
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	33 We now include the header files for the required definitions. From
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	34 <tt>stdio.h</tt> we use <tt>fopen()</tt>, <tt>fread()</tt>, <tt>fwrite()</tt>,
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	35 <tt>feof()</tt>, <tt>ferror()</tt>, and <tt>fclose()</tt> for file i/o, and
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	36 <tt>fputs()</tt> for error messages. From <tt>string.h</tt> we use
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	37 <tt>strcmp()</tt> for command line argument processing.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	38 From <tt>assert.h</tt> we use the <tt>assert()</tt> macro.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	39 From <tt>zlib.h</tt>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	40 we use the basic compression functions <tt>deflateInit()</tt>,
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	41 <tt>deflate()</tt>, and <tt>deflateEnd()</tt>, and the basic decompression
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	42 functions <tt>inflateInit()</tt>, <tt>inflate()</tt>, and
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	43 <tt>inflateEnd()</tt>.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	44 <pre><b>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	45 #include <stdio.h>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	46 #include <string.h>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	47 #include <assert.h>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	48 #include "zlib.h"
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	49 </b></pre><!-- -->
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	50 <tt>CHUNK</tt> is simply the buffer size for feeding data to and pulling data
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	51 from the <em>zlib</em> routines. Larger buffer sizes would be more efficient,
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	52 especially for <tt>inflate()</tt>. If the memory is available, buffers sizes
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	53 on the order of 128K or 256K bytes should be used.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	54 <pre><b>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	55 #define CHUNK 16384
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	56 </b></pre><!-- -->
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	57 The <tt>def()</tt> routine compresses data from an input file to an output file. The output data
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	58 will be in the <em>zlib</em> format, which is different from the <em>gzip</em> or <em>zip</em>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	59 formats. The <em>zlib</em> format has a very small header of only two bytes to identify it as
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	60 a <em>zlib</em> stream and to provide decoding information, and a four-byte trailer with a fast
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	61 check value to verify the integrity of the uncompressed data after decoding.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	62 <pre><b>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	63 /* Compress from file source to file dest until EOF on source.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	64 def() returns Z_OK on success, Z_MEM_ERROR if memory could not be
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	65 allocated for processing, Z_STREAM_ERROR if an invalid compression
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	66 level is supplied, Z_VERSION_ERROR if the version of zlib.h and the
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	67 version of the library linked do not match, or Z_ERRNO if there is
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	68 an error reading or writing the files. */
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	69 int def(FILE source, FILE dest, int level)
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	70 {
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	71 </b></pre>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	72 Here are the local variables for <tt>def()</tt>. <tt>ret</tt> will be used for <em>zlib</em>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	73 return codes. <tt>flush</tt> will keep track of the current flushing state for <tt>deflate()</tt>,
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	74 which is either no flushing, or flush to completion after the end of the input file is reached.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	75 <tt>have</tt> is the amount of data returned from <tt>deflate()</tt>. The <tt>strm</tt> structure
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	76 is used to pass information to and from the <em>zlib</em> routines, and to maintain the
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	77 <tt>deflate()</tt> state. <tt>in</tt> and <tt>out</tt> are the input and output buffers for
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	78 <tt>deflate()</tt>.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	79 <pre><b>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	80 int ret, flush;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	81 unsigned have;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	82 z_stream strm;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	83 char in[CHUNK];
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	84 char out[CHUNK];
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	85 </b></pre><!-- -->
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	86 The first thing we do is to initialize the <em>zlib</em> state for compression using
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	87 <tt>deflateInit()</tt>. This must be done before the first use of <tt>deflate()</tt>.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	88 The <tt>zalloc</tt>, <tt>zfree</tt>, and <tt>opaque</tt> fields in the <tt>strm</tt>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	89 structure must be initialized before calling <tt>deflateInit()</tt>. Here they are
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	90 set to the <em>zlib</em> constant <tt>Z_NULL</tt> to request that <em>zlib</em> use
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	91 the default memory allocation routines. An application may also choose to provide
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	92 custom memory allocation routines here. <tt>deflateInit()</tt> will allocate on the
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	93 order of 256K bytes for the internal state.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	94 (See <a href="zlib_tech.html"><em>zlib Technical Details</em></a>.)
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	95 <p>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	96 <tt>deflateInit()</tt> is called with a pointer to the structure to be initialized and
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	97 the compression level, which is an integer in the range of -1 to 9. Lower compression
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	98 levels result in faster execution, but less compression. Higher levels result in
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	99 greater compression, but slower execution. The <em>zlib</em> constant Z_DEFAULT_COMPRESSION,
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	100 equal to -1,
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	101 provides a good compromise between compression and speed and is equivalent to level 6.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	102 Level 0 actually does no compression at all, and in fact expands the data slightly to produce
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	103 the <em>zlib</em> format (it is not a byte-for-byte copy of the input).
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	104 More advanced applications of <em>zlib</em>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	105 may use <tt>deflateInit2()</tt> here instead. Such an application may want to reduce how
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	106 much memory will be used, at some price in compression. Or it may need to request a
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	107 <em>gzip</em> header and trailer instead of a <em>zlib</em> header and trailer, or raw
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	108 encoding with no header or trailer at all.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	109 <p>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	110 We must check the return value of <tt>deflateInit()</tt> against the <em>zlib</em> constant
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	111 <tt>Z_OK</tt> to make sure that it was able to
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	112 allocate memory for the internal state, and that the provided arguments were valid.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	113 <tt>deflateInit()</tt> will also check that the version of <em>zlib</em> that the <tt>zlib.h</tt>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	114 file came from matches the version of <em>zlib</em> actually linked with the program. This
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	115 is especially important for environments in which <em>zlib</em> is a shared library.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	116 <p>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	117 Note that an application can initialize multiple, independent <em>zlib</em> streams, which can
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	118 operate in parallel. The state information maintained in the structure allows the <em>zlib</em>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	119 routines to be reentrant.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	120 <pre><b>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	121 /* allocate deflate state */
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	122 strm.zalloc = Z_NULL;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	123 strm.zfree = Z_NULL;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	124 strm.opaque = Z_NULL;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	125 ret = deflateInit(&strm, level);
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	126 if (ret != Z_OK)
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	127 return ret;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	128 </b></pre><!-- -->
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	129 With the pleasantries out of the way, now we can get down to business. The outer <tt>do</tt>-loop
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	130 reads all of the input file and exits at the bottom of the loop once end-of-file is reached.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	131 This loop contains the only call of <tt>deflate()</tt>. So we must make sure that all of the
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	132 input data has been processed and that all of the output data has been generated and consumed
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	133 before we fall out of the loop at the bottom.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	134 <pre><b>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	135 /* compress until end of file */
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	136 do {
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	137 </b></pre>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	138 We start off by reading data from the input file. The number of bytes read is put directly
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	139 into <tt>avail_in</tt>, and a pointer to those bytes is put into <tt>next_in</tt>. We also
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	140 check to see if end-of-file on the input has been reached. If we are at the end of file, then <tt>flush</tt> is set to the
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	141 <em>zlib</em> constant <tt>Z_FINISH</tt>, which is later passed to <tt>deflate()</tt> to
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	142 indicate that this is the last chunk of input data to compress. We need to use <tt>feof()</tt>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	143 to check for end-of-file as opposed to seeing if fewer than <tt>CHUNK</tt> bytes have been read. The
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	144 reason is that if the input file length is an exact multiple of <tt>CHUNK</tt>, we will miss
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	145 the fact that we got to the end-of-file, and not know to tell <tt>deflate()</tt> to finish
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	146 up the compressed stream. If we are not yet at the end of the input, then the <em>zlib</em>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	147 constant <tt>Z_NO_FLUSH</tt> will be passed to <tt>deflate</tt> to indicate that we are still
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	148 in the middle of the uncompressed data.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	149 <p>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	150 If there is an error in reading from the input file, the process is aborted with
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	151 <tt>deflateEnd()</tt> being called to free the allocated <em>zlib</em> state before returning
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	152 the error. We wouldn't want a memory leak, now would we? <tt>deflateEnd()</tt> can be called
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	153 at any time after the state has been initialized. Once that's done, <tt>deflateInit()</tt> (or
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	154 <tt>deflateInit2()</tt>) would have to be called to start a new compression process. There is
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	155 no point here in checking the <tt>deflateEnd()</tt> return code. The deallocation can't fail.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	156 <pre><b>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	157 strm.avail_in = fread(in, 1, CHUNK, source);
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	158 if (ferror(source)) {
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	159 (void)deflateEnd(&strm);
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	160 return Z_ERRNO;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	161 }
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	162 flush = feof(source) ? Z_FINISH : Z_NO_FLUSH;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	163 strm.next_in = in;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	164 </b></pre><!-- -->
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	165 The inner <tt>do</tt>-loop passes our chunk of input data to <tt>deflate()</tt>, and then
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	166 keeps calling <tt>deflate()</tt> until it is done producing output. Once there is no more
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	167 new output, <tt>deflate()</tt> is guaranteed to have consumed all of the input, i.e.,
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	168 <tt>avail_in</tt> will be zero.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	169 <pre><b>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	170 /* run deflate() on input until output buffer not full, finish
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	171 compression if all of source has been read in */
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	172 do {
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	173 </b></pre>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	174 Output space is provided to <tt>deflate()</tt> by setting <tt>avail_out</tt> to the number
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	175 of available output bytes and <tt>next_out</tt> to a pointer to that space.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	176 <pre><b>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	177 strm.avail_out = CHUNK;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	178 strm.next_out = out;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	179 </b></pre>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	180 Now we call the compression engine itself, <tt>deflate()</tt>. It takes as many of the
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	181 <tt>avail_in</tt> bytes at <tt>next_in</tt> as it can process, and writes as many as
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	182 <tt>avail_out</tt> bytes to <tt>next_out</tt>. Those counters and pointers are then
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	183 updated past the input data consumed and the output data written. It is the amount of
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	184 output space available that may limit how much input is consumed.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	185 Hence the inner loop to make sure that
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	186 all of the input is consumed by providing more output space each time. Since <tt>avail_in</tt>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	187 and <tt>next_in</tt> are updated by <tt>deflate()</tt>, we don't have to mess with those
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	188 between <tt>deflate()</tt> calls until it's all used up.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	189 <p>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	190 The parameters to <tt>deflate()</tt> are a pointer to the <tt>strm</tt> structure containing
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	191 the input and output information and the internal compression engine state, and a parameter
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	192 indicating whether and how to flush data to the output. Normally <tt>deflate</tt> will consume
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	193 several K bytes of input data before producing any output (except for the header), in order
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	194 to accumulate statistics on the data for optimum compression. It will then put out a burst of
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	195 compressed data, and proceed to consume more input before the next burst. Eventually,
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	196 <tt>deflate()</tt>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	197 must be told to terminate the stream, complete the compression with provided input data, and
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	198 write out the trailer check value. <tt>deflate()</tt> will continue to compress normally as long
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	199 as the flush parameter is <tt>Z_NO_FLUSH</tt>. Once the <tt>Z_FINISH</tt> parameter is provided,
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	200 <tt>deflate()</tt> will begin to complete the compressed output stream. However depending on how
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	201 much output space is provided, <tt>deflate()</tt> may have to be called several times until it
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	202 has provided the complete compressed stream, even after it has consumed all of the input. The flush
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	203 parameter must continue to be <tt>Z_FINISH</tt> for those subsequent calls.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	204 <p>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	205 There are other values of the flush parameter that are used in more advanced applications. You can
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	206 force <tt>deflate()</tt> to produce a burst of output that encodes all of the input data provided
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	207 so far, even if it wouldn't have otherwise, for example to control data latency on a link with
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	208 compressed data. You can also ask that <tt>deflate()</tt> do that as well as erase any history up to
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	209 that point so that what follows can be decompressed independently, for example for random access
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	210 applications. Both requests will degrade compression by an amount depending on how often such
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	211 requests are made.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	212 <p>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	213 <tt>deflate()</tt> has a return value that can indicate errors, yet we do not check it here. Why
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	214 not? Well, it turns out that <tt>deflate()</tt> can do no wrong here. Let's go through
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	215 <tt>deflate()</tt>'s return values and dispense with them one by one. The possible values are
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	216 <tt>Z_OK</tt>, <tt>Z_STREAM_END</tt>, <tt>Z_STREAM_ERROR</tt>, or <tt>Z_BUF_ERROR</tt>. <tt>Z_OK</tt>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	217 is, well, ok. <tt>Z_STREAM_END</tt> is also ok and will be returned for the last call of
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	218 <tt>deflate()</tt>. This is already guaranteed by calling <tt>deflate()</tt> with <tt>Z_FINISH</tt>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	219 until it has no more output. <tt>Z_STREAM_ERROR</tt> is only possible if the stream is not
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	220 initialized properly, but we did initialize it properly. There is no harm in checking for
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	221 <tt>Z_STREAM_ERROR</tt> here, for example to check for the possibility that some
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	222 other part of the application inadvertently clobbered the memory containing the <em>zlib</em> state.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	223 <tt>Z_BUF_ERROR</tt> will be explained further below, but
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	224 suffice it to say that this is simply an indication that <tt>deflate()</tt> could not consume
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	225 more input or produce more output. <tt>deflate()</tt> can be called again with more output space
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	226 or more available input, which it will be in this code.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	227 <pre><b>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	228 ret = deflate(&strm, flush); /* no bad return value */
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	229 assert(ret != Z_STREAM_ERROR); /* state not clobbered */
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	230 </b></pre>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	231 Now we compute how much output <tt>deflate()</tt> provided on the last call, which is the
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	232 difference between how much space was provided before the call, and how much output space
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	233 is still available after the call. Then that data, if any, is written to the output file.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	234 We can then reuse the output buffer for the next call of <tt>deflate()</tt>. Again if there
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	235 is a file i/o error, we call <tt>deflateEnd()</tt> before returning to avoid a memory leak.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	236 <pre><b>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	237 have = CHUNK - strm.avail_out;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	238 if (fwrite(out, 1, have, dest) != have \|\| ferror(dest)) {
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	239 (void)deflateEnd(&strm);
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	240 return Z_ERRNO;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	241 }
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	242 </b></pre>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	243 The inner <tt>do</tt>-loop is repeated until the last <tt>deflate()</tt> call fails to fill the
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	244 provided output buffer. Then we know that <tt>deflate()</tt> has done as much as it can with
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	245 the provided input, and that all of that input has been consumed. We can then fall out of this
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	246 loop and reuse the input buffer.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	247 <p>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	248 The way we tell that <tt>deflate()</tt> has no more output is by seeing that it did not fill
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	249 the output buffer, leaving <tt>avail_out</tt> greater than zero. However suppose that
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	250 <tt>deflate()</tt> has no more output, but just so happened to exactly fill the output buffer!
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	251 <tt>avail_out</tt> is zero, and we can't tell that <tt>deflate()</tt> has done all it can.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	252 As far as we know, <tt>deflate()</tt>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	253 has more output for us. So we call it again. But now <tt>deflate()</tt> produces no output
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	254 at all, and <tt>avail_out</tt> remains unchanged as <tt>CHUNK</tt>. That <tt>deflate()</tt> call
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	255 wasn't able to do anything, either consume input or produce output, and so it returns
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	256 <tt>Z_BUF_ERROR</tt>. (See, I told you I'd cover this later.) However this is not a problem at
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	257 all. Now we finally have the desired indication that <tt>deflate()</tt> is really done,
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	258 and so we drop out of the inner loop to provide more input to <tt>deflate()</tt>.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	259 <p>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	260 With <tt>flush</tt> set to <tt>Z_FINISH</tt>, this final set of <tt>deflate()</tt> calls will
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	261 complete the output stream. Once that is done, subsequent calls of <tt>deflate()</tt> would return
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	262 <tt>Z_STREAM_ERROR</tt> if the flush parameter is not <tt>Z_FINISH</tt>, and do no more processing
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	263 until the state is reinitialized.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	264 <p>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	265 Some applications of <em>zlib</em> have two loops that call <tt>deflate()</tt>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	266 instead of the single inner loop we have here. The first loop would call
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	267 without flushing and feed all of the data to <tt>deflate()</tt>. The second loop would call
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	268 <tt>deflate()</tt> with no more
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	269 data and the <tt>Z_FINISH</tt> parameter to complete the process. As you can see from this
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	270 example, that can be avoided by simply keeping track of the current flush state.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	271 <pre><b>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	272 } while (strm.avail_out == 0);
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	273 assert(strm.avail_in == 0); /* all input will be used */
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	274 </b></pre><!-- -->
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	275 Now we check to see if we have already processed all of the input file. That information was
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	276 saved in the <tt>flush</tt> variable, so we see if that was set to <tt>Z_FINISH</tt>. If so,
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	277 then we're done and we fall out of the outer loop. We're guaranteed to get <tt>Z_STREAM_END</tt>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	278 from the last <tt>deflate()</tt> call, since we ran it until the last chunk of input was
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	279 consumed and all of the output was generated.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	280 <pre><b>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	281 /* done when last data in file processed */
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	282 } while (flush != Z_FINISH);
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	283 assert(ret == Z_STREAM_END); /* stream will be complete */
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	284 </b></pre><!-- -->
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	285 The process is complete, but we still need to deallocate the state to avoid a memory leak
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	286 (or rather more like a memory hemorrhage if you didn't do this). Then
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	287 finally we can return with a happy return value.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	288 <pre><b>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	289 /* clean up and return */
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	290 (void)deflateEnd(&strm);
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	291 return Z_OK;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	292 }
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	293 </b></pre><!-- -->
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	294 Now we do the same thing for decompression in the <tt>inf()</tt> routine. <tt>inf()</tt>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	295 decompresses what is hopefully a valid <em>zlib</em> stream from the input file and writes the
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	296 uncompressed data to the output file. Much of the discussion above for <tt>def()</tt>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	297 applies to <tt>inf()</tt> as well, so the discussion here will focus on the differences between
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	298 the two.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	299 <pre><b>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	300 /* Decompress from file source to file dest until stream ends or EOF.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	301 inf() returns Z_OK on success, Z_MEM_ERROR if memory could not be
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	302 allocated for processing, Z_DATA_ERROR if the deflate data is
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	303 invalid or incomplete, Z_VERSION_ERROR if the version of zlib.h and
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	304 the version of the library linked do not match, or Z_ERRNO if there
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	305 is an error reading or writing the files. */
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	306 int inf(FILE source, FILE dest)
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	307 {
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	308 </b></pre>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	309 The local variables have the same functionality as they do for <tt>def()</tt>. The
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	310 only difference is that there is no <tt>flush</tt> variable, since <tt>inflate()</tt>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	311 can tell from the <em>zlib</em> stream itself when the stream is complete.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	312 <pre><b>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	313 int ret;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	314 unsigned have;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	315 z_stream strm;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	316 char in[CHUNK];
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	317 char out[CHUNK];
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	318 </b></pre><!-- -->
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	319 The initialization of the state is the same, except that there is no compression level,
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	320 of course, and two more elements of the structure are initialized. <tt>avail_in</tt>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	321 and <tt>next_in</tt> must be initialized before calling <tt>inflateInit()</tt>. This
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	322 is because the application has the option to provide the start of the zlib stream in
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	323 order for <tt>inflateInit()</tt> to have access to information about the compression
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	324 method to aid in memory allocation. In the current implementation of <em>zlib</em>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	325 (up through versions 1.2.x), the method-dependent memory allocations are deferred to the first call of
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	326 <tt>inflate()</tt> anyway. However those fields must be initialized since later versions
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	327 of <em>zlib</em> that provide more compression methods may take advantage of this interface.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	328 In any case, no decompression is performed by <tt>inflateInit()</tt>, so the
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	329 <tt>avail_out</tt> and <tt>next_out</tt> fields do not need to be initialized before calling.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	330 <p>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	331 Here <tt>avail_in</tt> is set to zero and <tt>next_in</tt> is set to <tt>Z_NULL</tt> to
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	332 indicate that no input data is being provided.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	333 <pre><b>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	334 /* allocate inflate state */
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	335 strm.zalloc = Z_NULL;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	336 strm.zfree = Z_NULL;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	337 strm.opaque = Z_NULL;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	338 strm.avail_in = 0;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	339 strm.next_in = Z_NULL;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	340 ret = inflateInit(&strm);
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	341 if (ret != Z_OK)
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	342 return ret;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	343 </b></pre><!-- -->
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	344 The outer <tt>do</tt>-loop decompresses input until <tt>inflate()</tt> indicates
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	345 that it has reached the end of the compressed data and has produced all of the uncompressed
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	346 output. This is in contrast to <tt>def()</tt> which processes all of the input file.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	347 If end-of-file is reached before the compressed data self-terminates, then the compressed
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	348 data is incomplete and an error is returned.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	349 <pre><b>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	350 /* decompress until deflate stream ends or end of file */
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	351 do {
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	352 </b></pre>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	353 We read input data and set the <tt>strm</tt> structure accordingly. If we've reached the
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	354 end of the input file, then we leave the outer loop and report an error, since the
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	355 compressed data is incomplete. Note that we may read more data than is eventually consumed
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	356 by <tt>inflate()</tt>, if the input file continues past the <em>zlib</em> stream.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	357 For applications where <em>zlib</em> streams are embedded in other data, this routine would
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	358 need to be modified to return the unused data, or at least indicate how much of the input
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	359 data was not used, so the application would know where to pick up after the <em>zlib</em> stream.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	360 <pre><b>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	361 strm.avail_in = fread(in, 1, CHUNK, source);
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	362 if (ferror(source)) {
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	363 (void)inflateEnd(&strm);
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	364 return Z_ERRNO;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	365 }
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	366 if (strm.avail_in == 0)
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	367 break;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	368 strm.next_in = in;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	369 </b></pre><!-- -->
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	370 The inner <tt>do</tt>-loop has the same function it did in <tt>def()</tt>, which is to
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	371 keep calling <tt>inflate()</tt> until has generated all of the output it can with the
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	372 provided input.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	373 <pre><b>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	374 /* run inflate() on input until output buffer not full */
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	375 do {
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	376 </b></pre>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	377 Just like in <tt>def()</tt>, the same output space is provided for each call of <tt>inflate()</tt>.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	378 <pre><b>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	379 strm.avail_out = CHUNK;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	380 strm.next_out = out;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	381 </b></pre>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	382 Now we run the decompression engine itself. There is no need to adjust the flush parameter, since
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	383 the <em>zlib</em> format is self-terminating. The main difference here is that there are
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	384 return values that we need to pay attention to. <tt>Z_DATA_ERROR</tt>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	385 indicates that <tt>inflate()</tt> detected an error in the <em>zlib</em> compressed data format,
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	386 which means that either the data is not a <em>zlib</em> stream to begin with, or that the data was
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	387 corrupted somewhere along the way since it was compressed. The other error to be processed is
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	388 <tt>Z_MEM_ERROR</tt>, which can occur since memory allocation is deferred until <tt>inflate()</tt>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	389 needs it, unlike <tt>deflate()</tt>, whose memory is allocated at the start by <tt>deflateInit()</tt>.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	390 <p>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	391 Advanced applications may use
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	392 <tt>deflateSetDictionary()</tt> to prime <tt>deflate()</tt> with a set of likely data to improve the
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	393 first 32K or so of compression. This is noted in the <em>zlib</em> header, so <tt>inflate()</tt>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	394 requests that that dictionary be provided before it can start to decompress. Without the dictionary,
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	395 correct decompression is not possible. For this routine, we have no idea what the dictionary is,
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	396 so the <tt>Z_NEED_DICT</tt> indication is converted to a <tt>Z_DATA_ERROR</tt>.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	397 <p>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	398 <tt>inflate()</tt> can also return <tt>Z_STREAM_ERROR</tt>, which should not be possible here,
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	399 but could be checked for as noted above for <tt>def()</tt>. <tt>Z_BUF_ERROR</tt> does not need to be
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	400 checked for here, for the same reasons noted for <tt>def()</tt>. <tt>Z_STREAM_END</tt> will be
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	401 checked for later.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	402 <pre><b>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	403 ret = inflate(&strm, Z_NO_FLUSH);
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	404 assert(ret != Z_STREAM_ERROR); /* state not clobbered */
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	405 switch (ret) {
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	406 case Z_NEED_DICT:
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	407 ret = Z_DATA_ERROR; /* and fall through */
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	408 case Z_DATA_ERROR:
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	409 case Z_MEM_ERROR:
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	410 (void)inflateEnd(&strm);
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	411 return ret;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	412 }
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	413 </b></pre>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	414 The output of <tt>inflate()</tt> is handled identically to that of <tt>deflate()</tt>.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	415 <pre><b>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	416 have = CHUNK - strm.avail_out;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	417 if (fwrite(out, 1, have, dest) != have \|\| ferror(dest)) {
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	418 (void)inflateEnd(&strm);
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	419 return Z_ERRNO;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	420 }
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	421 </b></pre>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	422 The inner <tt>do</tt>-loop ends when <tt>inflate()</tt> has no more output as indicated
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	423 by not filling the output buffer, just as for <tt>deflate()</tt>. In this case, we cannot
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	424 assert that <tt>strm.avail_in</tt> will be zero, since the deflate stream may end before the file
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	425 does.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	426 <pre><b>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	427 } while (strm.avail_out == 0);
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	428 </b></pre><!-- -->
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	429 The outer <tt>do</tt>-loop ends when <tt>inflate()</tt> reports that it has reached the
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	430 end of the input <em>zlib</em> stream, has completed the decompression and integrity
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	431 check, and has provided all of the output. This is indicated by the <tt>inflate()</tt>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	432 return value <tt>Z_STREAM_END</tt>. The inner loop is guaranteed to leave <tt>ret</tt>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	433 equal to <tt>Z_STREAM_END</tt> if the last chunk of the input file read contained the end
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	434 of the <em>zlib</em> stream. So if the return value is not <tt>Z_STREAM_END</tt>, the
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	435 loop continues to read more input.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	436 <pre><b>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	437 /* done when inflate() says it's done */
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	438 } while (ret != Z_STREAM_END);
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	439 </b></pre><!-- -->
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	440 At this point, decompression successfully completed, or we broke out of the loop due to no
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	441 more data being available from the input file. If the last <tt>inflate()</tt> return value
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	442 is not <tt>Z_STREAM_END</tt>, then the <em>zlib</em> stream was incomplete and a data error
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	443 is returned. Otherwise, we return with a happy return value. Of course, <tt>inflateEnd()</tt>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	444 is called first to avoid a memory leak.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	445 <pre><b>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	446 /* clean up and return */
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	447 (void)inflateEnd(&strm);
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	448 return ret == Z_STREAM_END ? Z_OK : Z_DATA_ERROR;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	449 }
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	450 </b></pre><!-- -->
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	451 That ends the routines that directly use <em>zlib</em>. The following routines make this
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	452 a command-line program by running data through the above routines from <tt>stdin</tt> to
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	453 <tt>stdout</tt>, and handling any errors reported by <tt>def()</tt> or <tt>inf()</tt>.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	454 <p>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	455 <tt>zerr()</tt> is used to interpret the possible error codes from <tt>def()</tt>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	456 and <tt>inf()</tt>, as detailed in their comments above, and print out an error message.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	457 Note that these are only a subset of the possible return values from <tt>deflate()</tt>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	458 and <tt>inflate()</tt>.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	459 <pre><b>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	460 /* report a zlib or i/o error */
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	461 void zerr(int ret)
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	462 {
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	463 fputs("zpipe: ", stderr);
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	464 switch (ret) {
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	465 case Z_ERRNO:
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	466 if (ferror(stdin))
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	467 fputs("error reading stdin\n", stderr);
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	468 if (ferror(stdout))
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	469 fputs("error writing stdout\n", stderr);
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	470 break;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	471 case Z_STREAM_ERROR:
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	472 fputs("invalid compression level\n", stderr);
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	473 break;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	474 case Z_DATA_ERROR:
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	475 fputs("invalid or incomplete deflate data\n", stderr);
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	476 break;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	477 case Z_MEM_ERROR:
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	478 fputs("out of memory\n", stderr);
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	479 break;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	480 case Z_VERSION_ERROR:
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	481 fputs("zlib version mismatch!\n", stderr);
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	482 }
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	483 }
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	484 </b></pre><!-- -->
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	485 Here is the <tt>main()</tt> routine used to test <tt>def()</tt> and <tt>inf()</tt>. The
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	486 <tt>zpipe</tt> command is simply a compression pipe from <tt>stdin</tt> to <tt>stdout</tt>, if
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	487 no arguments are given, or it is a decompression pipe if <tt>zpipe -d</tt> is used. If any other
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	488 arguments are provided, no compression or decompression is performed. Instead a usage
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	489 message is displayed. Examples are <tt>zpipe < foo.txt > foo.txt.z</tt> to compress, and
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	490 <tt>zpipe -d < foo.txt.z > foo.txt</tt> to decompress.
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	491 <pre><b>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	492 /* compress or decompress from stdin to stdout */
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	493 int main(int argc, char **argv)
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	494 {
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	495 int ret;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	496
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	497 /* do compression if no arguments */
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	498 if (argc == 1) {
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	499 ret = def(stdin, stdout, Z_DEFAULT_COMPRESSION);
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	500 if (ret != Z_OK)
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	501 zerr(ret);
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	502 return ret;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	503 }
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	504
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	505 /* do decompression if -d specified */
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	506 else if (argc == 2 && strcmp(argv[1], "-d") == 0) {
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	507 ret = inf(stdin, stdout);
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	508 if (ret != Z_OK)
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	509 zerr(ret);
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	510 return ret;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	511 }
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	512
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	513 /* otherwise, report usage */
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	514 else {
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	515 fputs("zpipe usage: zpipe [-d] < source > dest\n", stderr);
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	516 return 1;
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	517 }
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	518 }
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	519 </b></pre>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	520 <hr>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	521 <i>Copyright (c) 2004 by Mark Adler<br>Last modified 13 November 2004</i>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	522 </body>
ae3a4bfb450b add some files of version 4.4.3 that have been forgotten. kent <kent@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	523 </html>

Mercurial > hg > CbC > CbC_gcc

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