time-to-botec

Benchmark sampling in different programming languages
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binary_to_symbolic.js (2570B)

      1 /**
      2 * @license Apache-2.0
      3 *
      4 * Copyright (c) 2018 The Stdlib Authors.
      5 *
      6 * Licensed under the Apache License, Version 2.0 (the "License");
      7 * you may not use this file except in compliance with the License.
      8 * You may obtain a copy of the License at
      9 *
     10 *    http://www.apache.org/licenses/LICENSE-2.0
     11 *
     12 * Unless required by applicable law or agreed to in writing, software
     13 * distributed under the License is distributed on an "AS IS" BASIS,
     14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     15 * See the License for the specific language governing permissions and
     16 * limitations under the License.
     17 */
     18 
     19 'use strict';
     20 
     21 var toBinaryString = require( '@stdlib/number/uint16/base/to-binary-string' );
     22 var lpad = require( '@stdlib/string/left-pad' );
     23 
     24 // Set this to "pretty" print results:
     25 var PRETTY_PRINT = false;
     26 
     27 var TOTAL;
     28 var masks;
     29 var bstr;
     30 var perm;
     31 var who;
     32 var tmp;
     33 var i;
     34 var j;
     35 
     36 // Total number of combinations (octal numbers):
     37 TOTAL = 8 * 8 * 8 * 8;
     38 
     39 // For each integer value (octal number), determine the symbolic notation equivalent to the value's binary representation...
     40 masks = new Array( TOTAL );
     41 for ( i = 0; i < TOTAL; i++ ) {
     42 	tmp = '';
     43 
     44 	// Convert the octal value to its binary representation:
     45 	bstr = toBinaryString( i );
     46 
     47 	// Discard the first four bits (a four digit octal number only uses 12 bits):
     48 	bstr = bstr.substring( 4 );
     49 
     50 	// Iterate over each bit starting from the fourth bit (left-to-right; the leftmost three bits are special mode bits, which are ignored when the mask is applied) and determine whether a bit is clear. If the bit is clear, the mask allows a permission to be enabled.
     51 	for ( j = 3; j < bstr.length; j++ ) {
     52 		who = (j-3) / 3;
     53 		if ( who === (who|0) ) { // is integer check
     54 			// Determine the user class:
     55 			who |= 0;
     56 			if ( who === 0 ) {
     57 				who = 'u';
     58 			} else if ( who === 1 ) {
     59 				who = 'g';
     60 			} else {
     61 				who = 'o';
     62 			}
     63 			if ( j >= 6 ) { // who|0 > 0
     64 				tmp += ',';
     65 			}
     66 			tmp += who + '=';
     67 		}
     68 		if ( bstr[ j ] === '0' ) {
     69 			// Determine the permission:
     70 			perm = j % 3;
     71 			if ( perm === 0 ) {
     72 				perm = 'r';
     73 			} else if ( perm === 1 ) {
     74 				perm = 'w';
     75 			} else {
     76 				perm = 'x';
     77 			}
     78 			tmp += perm;
     79 		}
     80 	}
     81 	// [ integer, octal, binary_string, symbolic_notation ]
     82 	masks[ i ] = [ i, lpad( i.toString( 8 ), 4, '0' ), bstr, tmp ];
     83 }
     84 
     85 if ( PRETTY_PRINT ) {
     86 	// Print the list of masks in symbolic notation:
     87 	for ( i = 0; i < TOTAL; i++ ) {
     88 		console.log( '%d = %s = %s = %s', masks[i][0], masks[i][1], masks[i][2], masks[i][3] );
     89 	}
     90 } else {
     91 	console.log( JSON.stringify( masks ) );
     92 }