jsos

college code for operating system fundamentals in js
utils.js

(2644B)
      1 /* --------  
      2    Utils.js
      3 
      4    Utility functions.
      5    -------- */
      6 
      7 /*
      8  * Removes leading and trailing spaces.
      9  */
     10 function trim(str) {
     11   return str.replace(/^\s+ | \s+$/g, "");	
     12 }
     13 
     14 /* 
     15  * Rotates each character of a string to the thirteenth spot.  
     16  * ie. a to n and z to m.
     17  */
     18 function rot13(str) {                       
     19   var retVal = "";    
     20   for (var i in str) {
     21     var ch = str[i];
     22     var code = 0;
     23     if ("abcedfghijklmABCDEFGHIJKLM".indexOf(ch) >= 0) {            
     24       code = str.charCodeAt(i) + 13;  
     25       retVal = retVal + String.fromCharCode(code);
     26     } else if ("nopqrstuvwxyzNOPQRSTUVWXYZ".indexOf(ch) >= 0) {
     27       code = str.charCodeAt(i) - 13;  
     28       retVal = retVal + String.fromCharCode(code);
     29     } else {
     30       retVal = retVal + ch;
     31     }
     32   }
     33   return retVal;
     34 }
     35 
     36 /*
     37  * Matches hex pattern. ie. FF 00 5G 8D 98
     38  */
     39 function isValidHex(str) {
     40   for (var i in str) {
     41     var ch = str[i];
     42     if ("abcedfABCDEF0123456789 ".indexOf(ch) < 0) {
     43       return false;
     44     }
     45   }
     46   return true;
     47 }
     48 
     49 /*
     50  * Matches hex byte. ie. FF or 8D etc
     51  */
     52 function isValidHexByte(str) {
     53   if(str.length > 2 || str.length < 1) return false;
     54   for (var i in str) {
     55     var ch = str[i];
     56     if ("abcedfABCDEF0123456789".indexOf(ch) < 0) {
     57       return false;
     58     }
     59   }
     60   return true;
     61 }
     62 
     63 /*
     64  * Padding string hex values 
     65  * ie. If size is 4 and hex string is 'a8' 
     66  * result will be '00a8'.
     67  */
     68 function pad(hex, size) {
     69   hex = hex.toString();
     70   while(hex.length < size) 
     71     hex = '0'+hex;
     72   return hex;
     73 }
     74 
     75 /*
     76  * Checks if the value is a valid byte or a value
     77  * of 0 to 255.
     78  */
     79 function isByte(value) {
     80   return isInt(value) && value > -1 && value < 256;
     81 }
     82 
     83 /*
     84  * Checks if input is a string type. 
     85  */
     86 function isString(input){
     87   return typeof(input)=='string';
     88 }
     89 
     90 /*
     91  * Converts a number to an ASCII character.
     92  */
     93 function hex2ASCII(num) {
     94   if(num==0) return null;
     95   var hex = num.toString(16);
     96   var str = '';
     97   for (var i=0; i<hex.length; i+=2)
     98     str += String.
     99         fromCharCode(parseInt(hex.substr(i, 2), 16));
    100   return str;
    101 }
    102 
    103 /*
    104  * Converts ASCII character to a number.
    105  */
    106 function ascii2hex(pStr) {
    107   var tempstr = [];
    108   for (a=0; a<pStr.length; a++) {
    109     tempstr[a] = pStr.charCodeAt(a).toString(16);
    110   }
    111   return tempstr;
    112 }
    113 
    114 /*
    115  * Converts a string to array. Each array element is
    116  * a string character.
    117  */
    118 function string2Array(string) {
    119   string = string.toString();
    120   var arr = [];
    121   for(i=0; i<string.length; i++) 
    122     arr[i] = string.substring(i,i+1);
    123   return arr;
    124 }
    125 
    126 /*
    127  * Checks if the value is an integer.
    128  */
    129 function isInt(value){ 
    130   return ((parseFloat(value) == parseInt(value)) 
    131         && !isNaN(value))
    132 }