Applications/Zlib - Revision history

Pysdlb: /* Further Information */

2022-11-16T11:10:59Z

‎Further Information

Pysdlb at 12:50, 24 May 2021

2021-05-24T12:50:07Z

Pysdlb at 12:49, 24 May 2021

2021-05-24T12:49:37Z

Pysdlb: Pysdlb moved page Zlib to Applications/Zlib without leaving a redirect

2017-04-04T15:12:33Z

Pysdlb moved page Zlib to Applications/Zlib without leaving a redirect

Pysdlb at 15:10, 4 April 2017

2017-04-04T15:10:39Z

Pysdlb: Created page with "==Application Details== * Description: zlib is a software library used for data compression. * Version: 1.2.8 (compiled with gcc) * Modules: zlib/gcc/1.2.8 * Licence: Free a..."

2017-04-04T15:09:48Z

Created page with "==Application Details== * Description: zlib is a software library used for data compression. * Version: 1.2.8 (compiled with gcc) * Modules: zlib/gcc/1.2.8 * Licence: Free a..."

New page

==Application Details==

* Description: zlib is a software library used for data compression.
* Version: 1.2.8 (compiled with gcc)
* Modules: zlib/gcc/1.2.8
* Licence: Free and open source

==Usage Examples==

zlib is designed to be a free, general-purpose, legally unencumbered -- that is, not covered by any patents -- lossless data-compression library for use on virtually any computer hardware and operating system. The zlib data format is itself portable across platforms. Unlike the LZW compression method used in Unix compress(1) and in the GIF image format, the compression method currently used in zlib essentially never expands the data. (LZW can double or triple the file size in extreme cases.) zlib's memory footprint is also independent of the input data and can be reduced, if necessary, at some cost in compression.

A code example is shown below, using zlib

<pre style="background-color: #f5f5dc; color: black; font-family: monospace, sans-serif;">

#include <stdio.h>
#include <zlib.h>
#include <stdlib.h>
#include <string.h>

/* CHUNK is the size of the memory chunk used by the zlib routines. */

#define CHUNK 0x4000

/* The following macro calls a zlib routine and checks the return
value. If the return value ("status") is not OK, it prints an error
message and exits the program. Zlib's error statuses are all less
than zero. */

#define CALL_ZLIB(x) { \
int status; \
status = x; \
if (status < 0) { \
fprintf (stderr, \
"%s:%d: %s returned a bad status of %d.\n", \
__FILE__, __LINE__, #x, status); \
exit (EXIT_FAILURE); \
} \
}

/* These are parameters to deflateInit2. See
http://zlib.net/manual.html for the exact meanings. */

#define windowBits 15
#define GZIP_ENCODING 16

static void strm_init (z_stream * strm)
{
strm->zalloc = Z_NULL;
strm->zfree = Z_NULL;
strm->opaque = Z_NULL;
CALL_ZLIB (deflateInit2 (strm, Z_DEFAULT_COMPRESSION, Z_DEFLATED,
windowBits | GZIP_ENCODING, 8,
Z_DEFAULT_STRATEGY));
}

/* Example text to print out. */

static const char * message =
"Shall I compare thee to a summer's day?\n"
"Thou art more lovely and more temperate:\n"
"Rough winds do shake the darling buds of May,\n"
"And summer's lease hath all too short a date;\n"
;

int main ()
{
unsigned char out[CHUNK];
z_stream strm;
strm_init (& strm);
strm.next_in = (unsigned char *) message;
strm.avail_in = strlen (message);
do {
int have;
strm.avail_out = CHUNK;
strm.next_out = out;
CALL_ZLIB (deflate (& strm, Z_FINISH));
have = CHUNK - strm.avail_out;
fwrite (out, sizeof (char), have, stdout);
}
while (strm.avail_out == 0);
deflateEnd (& strm);

return 0;
}

</pre>

==Further Information==

* [http://www.zlib.net/ http://www.zlib.net/]
* [https://en.wikipedia.org/wiki/Zlib https://en.wikipedia.org/wiki/Zlib]

{|
|style="width:5%; border-width: 0" | [[File:icon_home.png]]
|style="width:95%; border-width: 0" |
* [[Main_Page|Home]]
* [[Applications|Application support]]
* [[General|General]]
* [[Training|Training]]
* [[Programming|Programming support]]

|-
|}

← Older revision		Revision as of 11:10, 16 November 2022
Line 92:		Line 92:
	* [https://en.wikipedia.org/wiki/Zlib https://en.wikipedia.org/wiki/Zlib]		* [https://en.wikipedia.org/wiki/Zlib https://en.wikipedia.org/wiki/Zlib]

−	{\|	+	{{Librariespagenav}}
−	~~\|style="width:5%; border-width: 0" \| [[File:icon_home.png]]~~
−	~~\|style="width:95%; border-width: 0" \|~~
−	* [[Main_Page\|Home]]
−	* [[Applications\|Application support]]
−	* [[General\|General]]
−	* [[Training\|Training]]
−	* [[Programming\|Programming support]]
−
−	\|-
−	\|}

← Older revision		Revision as of 12:50, 24 May 2021
Line 1:		Line 1:
		+	__TOC__
		+
	==Application Details==		==Application Details==

@@ Line 23: / Line 23: @@
 #define CHUNK 0x4000
-/* The following macro calls a zlib routine and checks the return
+/* The following macro calls a zlib routine and checks the return value. If the return value ("status") is not OK, it prints an error message and exits the program. Zlib's error statuses are all less than zero. */
 #define CALL_ZLIB(x) {                                                  \

← Older revision	Revision as of 15:12, 4 April 2017
(No difference)

@@ Line 8: / Line 8: @@
 ==Usage Examples==
-zlib is designed to be a free, general-purpose, legally unencumbered -- that is, not covered by any patents -- lossless data-compression library for use on virtually any computer hardware and operating system. The zlib data format is itself portable across platforms. Unlike the LZW compression method used in Unix compress(1) and in the GIF image format, the compression method currently used in zlib essentially never expands the data. (LZW can double or triple the file size in extreme cases.) zlib's memory footprint is also independent of the input data and can be reduced, if necessary, at some cost in compression.
+zlib is designed to be a free, general-purpose, legally unencumbered -- that is, not covered by any patents -- lossless data-compression library for use on virtually any computer hardware and operating system. The zlib data format is itself portable across platforms. Unlike the LZW compression method used in Unix compress and in the GIF image format, the compression method currently used in zlib essentially never expands the data. (LZW can double or triple the file size in extreme cases.)
+A code example is shown below, using '''zlib'''
 <pre style="background-color: #f5f5dc; color: black; font-family: monospace, sans-serif;">