Gzip (String function) - Revision history

Tom at 13:38, 19 May 2026

2026-05-19T13:38:14Z

← Older revision		Revision as of 13:38, 19 May 2026
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	{{Template:String:Gzip subtitle}}		{{Template:String:Gzip subtitle}}
	This function compresses a longstring using the "deflate" algorithm, which is described completely in RFC 1951. The GZIP format is described in RFC 1952. It is very effective with HTML and XML data.		This function compresses a longstring using the "deflate" algorithm, which is described completely in RFC 1951. The GZIP format is described in RFC 1952. It is very effective with HTML and XML data.

	==Syntax==		==Syntax==
	~~{{Template~~:String~~:Gzip syntax}}~~		<p class="syntax"><span class="term">%outString</span><span class="literal"> =</span> <span class="term">string</span><span class="literal">:Gzip</span><span class="squareb">[</span><span class="literal">(</span> <span class="squareb">[</span><span class="literal" title="Boolean">FixedCode=</span> <span class="term" title="Boolean">boolean</span><span class="squareb">]</span><span class="comma">,</span> <span class="squareb">[</span><span class="literal" title="Boolean">LazyMatch=</span> <span class="term" title="Boolean">boolean</span><span class="squareb">]</span><span class="comma">,</span> -
			<span class="squareb">[</span><span class="literal" title="Number">MaxChain=</span> <span class="term" title="Number">number</span><span class="squareb">]</span><span class="comma">,</span> <span class="squareb">[</span><span class="literal" title="String">Filename=</span> <span class="term" title="String">string</span><span class="squareb">]</span><span class="comma">,</span> -
			<span class="squareb">[</span><span class="literal" title="Number">LastModified=</span> <span class="term" title="Number">number</span><span class="squareb">]</span><span class="comma">,</span> -
			<span class="squareb">[</span><span class="literal" title="Boolean">Software=</span> <span class="term" title="Boolean">boolean</span><span class="squareb">]</span><span class="literal">)</span><span class="squareb">]</span></p>

	===Syntax terms===		===Syntax terms===
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	<tr><th><var>Filename</var></th>		<tr><th><var>Filename</var></th>
	<td><var>Filename</var> is an optional, name required, parameter that is a string to be stored as the internal name of the compressed string. Decompression programs will use this name for the output file when the string is un-zipped. The maximum length of the file name is 32 bytes. </td></tr>		<td><var>Filename</var> is an optional, name required, parameter that is a string to be stored as the internal name of the compressed string. Decompression programs will use this name for the output file when the string is un-zipped. The maximum length of the file name is 32 bytes.
			</td></tr>

	<tr><th><var>LastModified</var></th>		<tr><th><var>LastModified</var></th>
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	After <var>Gzip</var> stores a value into <var class="term">%outString</var>, the <var>LastModified</var> date/time stamp can be obtained with the <var>[[GunzipDatetimeNS (String function)\|GunzipDatetimeNS]]</var> function, but note that its output is in seconds, not milliseconds.		After <var>Gzip</var> stores a value into <var class="term">%outString</var>, the <var>LastModified</var> date/time stamp can be obtained with the <var>[[GunzipDatetimeNS (String function)\|GunzipDatetimeNS]]</var> function, but note that its output is in seconds, not milliseconds.
			</td></tr>

			<tr><th><var>Software</var></th>
			<td>[Introduced in Model 204 version 8.0]
			<p><var>Software</var> is an optional, [[Notation conventions for methods#Named parameters\|name required]], parameter that is a <var>[[Boolean_enumeration#Using_Boolean_enumerations\|Boolean]]</var> value that specifies whether to force the use of software compression instead of hardware compression.</p>
			<ul>
			<li>When <code>software=true</code>, compression is always performed in software, even if the DFLTCC hardware instruction is available on the processor. This can be useful for diagnostic purposes or when byte-for-byte reproducibility with pre-8.0 behavior is required.</li>
			<li>When <code>software=false</code> (the default), hardware compression is used automatically when DFLTCC is available (IBM z15 and above), falling back to software compression on older processors.</li>
			</ul>
			The default value for this argument is <var>False</var>.
	</td></tr>		</td></tr>
	</table>		</table>
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	==Usage notes==		==Usage notes==
	<ul>		<ul>
	<li>The <var>[[NCMPBUF parameter\|NCMPBUF]]</var> parameter must be set by User 0 before <var>Gzip</var> can be used. If <var>Gzip</var> is called and the <var>NCMPBUF</var> value is 0, the request is cancelled.		<li>The <var>[[NCMPBUF parameter\|NCMPBUF]]</var> parameter must be set by User 0 before <var>Gzip</var> can be used. If <var>Gzip</var> is called and the <var>NCMPBUF</var> value is 0, the request is cancelled.
	</ul>		</ul>

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	<ul>		<ul>
	<li>The inverse of <var>Gzip</var> is <var>[[Gunzip (String function)\|Gunzip]]</var>.		<li>The inverse of <var>Gzip</var> is <var>[[Gunzip (String function)\|Gunzip]]</var>.
	<li>Other related methods:		<li>Other related methods:
	<ul>		<ul>
	<li><var>[[GunzipDatetimeNS (String function)\|GunzipDatetimeNS]]</var>		<li><var>[[GunzipDatetimeNS (String function)\|GunzipDatetimeNS]]</var>
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	<li><var>[[Deflate (String function)\|Deflate]]</var>		<li><var>[[Deflate (String function)\|Deflate]]</var>
	<li><var>[[Inflate (String function)\|Inflate]]</var>		<li><var>[[Inflate (String function)\|Inflate]]</var>
	</ul>		</ul>
	</ul>		</ul>

	{{Template:String:Gzip footer}}		{{Template:String:Gzip footer}}

ELowell at 21:19, 3 September 2015

2015-09-03T21:19:15Z

← Older revision		Revision as of 21:19, 3 September 2015
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	{{Template:String:Gzip subtitle}}		{{Template:String:Gzip subtitle}}

	This function compresses a longstring using the "deflate" algorithm, which is described completely in RFC 1951. The GZIP format is described in RFC 1952. It is very effective with HTML and XML data.		This function compresses a longstring using the "deflate" algorithm, which is described completely in RFC 1951. The GZIP format is described in RFC 1952. It is very effective with HTML and XML data.

JAL2 at 19:12, 9 August 2012

2012-08-09T19:12:43Z

← Older revision		Revision as of 19:12, 9 August 2012
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	==Usage notes==		==Usage notes==
			<ul>
			<li>The <var>[[NCMPBUF parameter\|NCMPBUF]]</var> parameter must be set by User 0 before <var>Gzip</var> can be used. If <var>Gzip</var> is called and the <var>NCMPBUF</var> value is 0, the request is cancelled.
			</ul>

	==See also==		==See also==

JAL2 at 19:04, 9 August 2012

2012-08-09T19:04:11Z

← Older revision		Revision as of 19:04, 9 August 2012
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	{{Template:String:Gzip subtitle}}		{{Template:String:Gzip subtitle}}

			This function compresses a longstring using the "deflate" algorithm, which is described completely in RFC 1951. The GZIP format is described in RFC 1952. It is very effective with HTML and XML data.

	==Syntax==		==Syntax==

JAL2: /* Syntax terms */

2012-08-09T18:53:27Z

Syntax terms

← Older revision		Revision as of 18:53, 9 August 2012
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	<tr><th><var>Filename</var></th>		<tr><th><var>Filename</var></th>
	<td><var>Filename</var> is an optional, name required, parameter that is a string ~~([[under construction]])~~</td></tr>		<td><var>Filename</var> is an optional, name required, parameter that is a string to be stored as the internal name of the compressed string. Decompression programs will use this name for the output file when the string is un-zipped. The maximum length of the file name is 32 bytes. </td></tr>

	<tr><th><var>LastModified</var></th>		<tr><th><var>LastModified</var></th>

JAL2 at 18:40, 9 August 2012

2012-08-09T18:40:20Z

← Older revision		Revision as of 18:40, 9 August 2012
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	<tr><th><var>FixedCode</var></th>		<tr><th><var>FixedCode</var></th>
	<td><var>~~Boolean~~</var> ~~value (~~[[~~under construction~~]]).</td></tr>		<td><var>FixedCode</var> is an optional, [[Notation conventions for methods#Named parameters\|name required]], parameter that is a <var>[[Boolean_enumeration#Using_Boolean_enumerations\|Boolean]]</var> value that specifies whether the compression uses fixed codes or is dynamic, based on the contents of the input <var class="term">string</var>.
			<ul>
			<li>With fixed code compression (<code>fixedCode=true</code>), the tables used for compression (defined as part of RFC 1951) are somewhat optimized for ASCII character data, but they slightly decrease the amount of CPU required to perform compression. Also, since the codes are already defined as part of the specification, they are not included in the compressed data.
			<li>With dynamic compression (<code>fixedCode=false</code>), the compression code tables are generated based on the input data. Dynamic tables typically provide somewhat better compression on most types of data. There is a very slight CPU overhead in computing the frequencies of byte values in the input data. Also, since the code tables are dynamic, they are included as part of the compressed data. This will increase the size of the compressed longstring, but these tables are small, since they are also stored in a compressed form.
			</ul>
			The default value for this argument is <var>False</var> (use dynamic compression).</td></tr>

	<tr><th><var>LazyMatch</var></th>		<tr><th><var>LazyMatch</var></th>
	<td><var>Boolean</var> value (~~[[under construction]]~~)</td></tr>		<td><var>LazyMatch</var> is an optional, name required, parameter that is a <var>Boolean</var> value that specifies whether to use "lazy match" compression, as specified in RFC 1951.
			The default value for this argument is <var>False</var> (do not use "lazy match" compression).</td></tr>

	<tr><th><var>MaxChain</var></th>		<tr><th><var>MaxChain</var></th>
	<td>~~number ([[under construction]])~~</td></tr>		<td><var>MaxChain</var> is an optional, name required, parameter that is a numeric value that specifies the maximum hash chain length, as explained in RFC 1951.
			The default value for this argument is 0. If specified, it must be between 0 and 99, inclusive.</td></tr>

	<tr><th><var>Filename</var></th>		<tr><th><var>Filename</var></th>
	<td>string ([[under construction]])</td></tr>		<td><var>Filename</var> is an optional, name required, parameter that is a string ([[under construction]])</td></tr>

	<tr><th><var>LastModified</var></th>		<tr><th><var>LastModified</var></th>

JAL2: /* See also */

2012-08-09T18:25:18Z

JAL2: /* See also */

2012-08-09T17:58:55Z

JAL2: /* See also */

2012-08-08T18:32:09Z

JAL2 at 18:31, 8 August 2012

2012-08-08T18:31:46Z

← Older revision		Revision as of 18:31, 8 August 2012
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	==Syntax==		==Syntax==
	{{Template:String:Gzip syntax}}		{{Template:String:Gzip syntax}}

	===Syntax terms===		===Syntax terms===
	<table class="syntaxTable">		<table class="syntaxTable">
	<tr><th>%outString</th><td>The result of the GZIP operation, compressing the method object <var class="term">string</var>.</td></tr>		<tr><th>%outString</th>
			<td>The result of the GZIP operation, compressing the method object <var class="term">string</var>.</td></tr>

	<tr><th>string</th>		<tr><th>string</th>
	<td>The string to be compressed by the GZIP operation.</td></tr>		<td>The string to be compressed by the GZIP operation.</td></tr>

	<tr><th><var>FixedCode</var></th>		<tr><th><var>FixedCode</var></th>
	<td><var>Boolean</var> value ([[under construction]]).</td></tr>		<td><var>Boolean</var> value ([[under construction]]).</td></tr>

	<tr><th><var>LazyMatch</var></th>		<tr><th><var>LazyMatch</var></th>
	<td><var>Boolean</var> value ([[under construction]])</td></tr>		<td><var>Boolean</var> value ([[under construction]])</td></tr>

	<tr><th><var>MaxChain</var></th>		<tr><th><var>MaxChain</var></th>
	<td>number ([[under construction]])</td></tr>		<td>number ([[under construction]])</td></tr>

	<tr><th><var>Filename</var></th>		<tr><th><var>Filename</var></th>
	<td>string ([[under construction]])</td></tr>		<td>string ([[under construction]])</td></tr>

	<tr><th><var>LastModified</var></th>		<tr><th><var>LastModified</var></th>
	<td>The date/time stamp to be stored as a component of <var class="term">%outString</var>, expressed as the number of milliseconds since 12:00 AM, Jan 1, 1900. The default is the current date and time (that is, <var>[[CurrentTimeMilliseconds (System function)\|%(System):CurrentTimeMilliseconds]]</var>).		<td>The date/time stamp to be stored as a component of <var class="term">%outString</var>, expressed as the number of milliseconds since 12:00 AM, Jan 1, 1900. The default is the current date and time (that is, <var>[[CurrentTimeMilliseconds (System function)\|%(System):CurrentTimeMilliseconds]]</var>).
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	==Usage notes==		==Usage notes==

			==See also==
	<ul>		<ul>
	<li>The inverse of <var>Gzip</var> is <var>[[Gunzip (String function)\|Gunzip]]</var>.		<li>The inverse of <var>Gzip</var> is <var>[[Gunzip (String function)\|Gunzip]]</var>.
	<~~/ul~~>		<li>Other related methods:

	~~==Examples==~~
	~~==See also==~~
	~~Related~~ methods:
	<ul>		<ul>
	~~<li><var>[[Gunzip (String function)\|Gunzip]]</var>~~
	<li><var>[[Deflate (String function)\|Deflate]]</var>		<li><var>[[Deflate (String function)\|Deflate]]</var>
			<li><var>[[Inflate (String function)\|Inflate]]</var>
			</ul>
	</ul>		</ul>


	{{Template:String:Gzip footer}}		{{Template:String:Gzip footer}}

← Older revision		Revision as of 18:25, 9 August 2012
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	<li><var>[[GunzipDatetimeNS (String function)\|GunzipDatetimeNS]]</var>		<li><var>[[GunzipDatetimeNS (String function)\|GunzipDatetimeNS]]</var>
	<li><var>[[GunzipFilename (String function)\|GunzipFilename]]</var>		<li><var>[[GunzipFilename (String function)\|GunzipFilename]]</var>
			<li><var>[[Zip (String function)\|Zip]]</var>
	<li><var>[[Deflate (String function)\|Deflate]]</var>		<li><var>[[Deflate (String function)\|Deflate]]</var>
	<li><var>[[Inflate (String function)\|Inflate]]</var>		<li><var>[[Inflate (String function)\|Inflate]]</var>

← Older revision		Revision as of 17:58, 9 August 2012
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	<li>Other related methods:		<li>Other related methods:
	<ul>		<ul>
			<li><var>[[GunzipDatetimeNS (String function)\|GunzipDatetimeNS]]</var>
			<li><var>[[GunzipFilename (String function)\|GunzipFilename]]</var>
	<li><var>[[Deflate (String function)\|Deflate]]</var>		<li><var>[[Deflate (String function)\|Deflate]]</var>
	<li><var>[[Inflate (String function)\|Inflate]]</var>		<li><var>[[Inflate (String function)\|Inflate]]</var>

← Older revision		Revision as of 18:32, 8 August 2012
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	</ul>		</ul>
	</ul>		</ul>


	{{Template:String:Gzip footer}}		{{Template:String:Gzip footer}}