BitAndString (String function): Difference between revisions

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{{Template:String:BitAndString subtitle}}
{{Template:String:BitAndString subtitle}}


This function does a logical AND of the bits in two strings.
==Syntax==
==Syntax==
{{Template:String:BitAndString syntax}}
{{Template:String:BitAndString syntax}}
===Syntax terms===
===Syntax terms===
<table class="syntaxTable">
<table class="syntaxTable">
<tr><th>string</th><td>string</td></tr>
<tr><th>%result</th><td>A string to receive the result of ANDing together the bits in <var class="term">string</var> and <var class="term">andBits</var>.</td></tr>
<tr><th>string</th>
<tr><th>string</th>
<td>String object</td></tr>
<td>One of the strings to be ANDed.</td></tr>
<tr><th>andBits</th>
<tr><th>andBits</th>
<td>String object</td></tr>
<td>The other string to be ANDed.</td></tr>
<tr><th>pad</th>
<tr><th>pad</th>
<td>C object</td></tr>
<td>A single character that indicates the character with which the shorter of the two input strings is to be extended. As many copies of <var class="term">pad</var> are used as is required to make the shorter string as long as the longer. If both strings are of equal length, no padding is required. The default value of <var class="term">pad</var> is <code>'00':x</code>.</td></tr>
</table>
</table>
==Usage notes==
==Usage notes==
<ul>
<li>Using a null <var class="term">string</var> or <var class="term">andBits</var> is an easy way of ANDing each byte in a string with a specific byte value (the <var class="term">pad</var> value).
<li><var>BitAndString</var> is most useful for working with binary data, for example binary data being sent or received with <var class="product">[[Janus Sockets]]</var>.
</ul>
==Examples==
==Examples==
The following example turns off the low order bit of a numeric value's string representation, rounding every digit down to an even number (because EBCDIC binary digits map 0-9 to hex values X'F0'-X'F9'):
<p class="pre">
%evenDigits = %digits:bitAndString('', pad='FE':x)
</p>
In, the above code, if <code>%digits</code> were <code>'31415926'</code>, <code>%evenDigits</code> would be set to <code class="output">'20404826'</code>.
The following example:
<p class="pre">printText {~='Red':bitAndString('Green', pad='FF':x)}
</p>
outputs
<p class="output">'Red':bitAndString('Green', pad='FF':x)=Aaden
</p>
To see why this is correct run the following:
<p class="pre">[[Printtext|printText]] {~='Red':stringToHex}
printText {~='Green':stringToHex}
printText {~='Red':bitAndString('Green', pad='FF':x):stringToHex}
</p>
which outputs
<p class="output">'Red':[[StringToHex (String function)|stringToHex]]=D98584
'Green':stringToHex=C799858595
'Red':bitAndString('Green', pad='FF':x):stringToHex=C181848595
</p>
==See also==
==See also==
{{Template:String:BitAndString subtitle}}
{{Template:String:BitAndString footer}}

Revision as of 04:42, 27 January 2011

Do bitwise And of strings (String class)

[Introduced in Sirius Mods 7.9]


This function does a logical AND of the bits in two strings.

Syntax

%result = string:BitAndString( andBits, [Pad= c])

Syntax terms

%resultA string to receive the result of ANDing together the bits in string and andBits.
string One of the strings to be ANDed.
andBits The other string to be ANDed.
pad A single character that indicates the character with which the shorter of the two input strings is to be extended. As many copies of pad are used as is required to make the shorter string as long as the longer. If both strings are of equal length, no padding is required. The default value of pad is '00':x.

Usage notes

  • Using a null string or andBits is an easy way of ANDing each byte in a string with a specific byte value (the pad value).
  • BitAndString is most useful for working with binary data, for example binary data being sent or received with Janus Sockets.

Examples

The following example turns off the low order bit of a numeric value's string representation, rounding every digit down to an even number (because EBCDIC binary digits map 0-9 to hex values X'F0'-X'F9'):

%evenDigits = %digits:bitAndString(, pad='FE':x)

In, the above code, if %digits were '31415926', %evenDigits would be set to '20404826'.

The following example:

printText {~='Red':bitAndString('Green', pad='FF':x)}

outputs

'Red':bitAndString('Green', pad='FF':x)=Aaden

To see why this is correct run the following:

printText {~='Red':stringToHex} printText {~='Green':stringToHex} printText {~='Red':bitAndString('Green', pad='FF':x):stringToHex}

which outputs

'Red':stringToHex=D98584 'Green':stringToHex=C799858595 'Red':bitAndString('Green', pad='FF':x):stringToHex=C181848595

See also