Diff code: bcmod

Function:
Description: Get the modulus of the left_operand using modulus.
Version A:
Version B:
bcmod version 510bcmod version 521
 1/*
  1/*
 2Note: this function is a hack, and it only supports the use cases I require at
  2Note: this function is a hack, and it only supports the use cases I require at
 3the moment, being: arbitrary precision integer left_operand and native precision positive integer modulus (must fit in a native number, i.e. a double).
  3the moment, being: an arbitrary precision decimal left_operand and native precision positive decimal modulus (must fit in a native number, i.e. a double).
 4*/
  4*/
 5function bcmod( left_operand, modulus ) {
  5function bcmod( left_operand, modulus ) {
  6  // John was here!
  7  // Key was here!
 6  var i, d;
  8  var i, d;
 7  function split( operand ) {
  9  function split( operand ) {
 8    var parts = operand.split( '.' );
 10    var parts = operand.split( '.' );
 9    var i = parts[ 0 ];
 11    var i = parts[ 0 ];
10    var d = '0.' + ( parts.length > 1 ? parts[ 1 ] : '0' );
 12    var d = '0.' + ( parts.length > 1 ? parts[ 1 ] : '0' );
11    return { "i": i, "d": d };
 13    return { "i": i, "d": d };
12  }
 14  }
13  //modulus = Math.round( parseFloat( modulus ) );
 15  //modulus = Math.round( parseFloat( modulus ) );
14  modulus = parseFloat( modulus );
 16  modulus = parseFloat( modulus );
15  modulus = abs( modulus );
 17  modulus = abs( modulus );
16  if ( modulus === 0 ) { return null; }
 18  if ( modulus === 0 ) { return null; }
17  var take = 4;
 19  var take = 4;
18  var modulus_limit = Math.pow( 10, take );
 20  var modulus_limit = Math.pow( 10, take );
19  if ( modulus >= modulus_limit ) {
 21  if ( modulus >= modulus_limit ) {
20    throw new Error( "Modulus cannot be " + modulus_limit + " or greater." );
 22    throw new Error( "Modulus cannot be " + modulus_limit + " or greater." );
21  }
 23  }
22  var result = 0;
 24  var result = 0;
23  var r = split( left_operand );
 25  var r = split( left_operand );
24  i = r.i; d = r.d;
 26  i = r.i; d = r.d;
25  var read_length = 0;
 27  var read_length = 0;
26  function read() {
 28  function read() {
27    read_length = i.length < take ? i.length : ( take );
 29    read_length = i.length < take ? i.length : ( take );
28    var result = i.substr( 0, take );
 30    var result = i.substr( 0, take );
29    i = i.substr( take );
 31    i = i.substr( take );
30    return result;
 32    return result;
31  }
 33  }
32  function round( value ) {
 34  function round( value ) {
 35    //console.log( "V:" + value );
33               //0.8999999999999997
 36               //0.8999999999999997
34               //0.09999999999999984
 37               //0.09999999999999984
35               //0.29999999999999993
 38               //0.29999999999999993
36               //0.7999999999999998
 39               //0.7999999999999998
37               //0.8999999999999999
 40               //0.8999999999999999
38               //0.10000000000000009
 41               //0.10000000000000009
39               //0.029999999999999985
 42               //0.029999999999999985
40    var units = '0.0000000000000000';
 43    var units = '0.0000000000000000';
41    function get_chars( s ) {
 44    function get_chars( s ) {
42      var gc_result = [];
 45      var result = [];
43      for ( var j = 0, jl = s.length; j < jl; j++ ) {
 46      for ( var j = 0, jl = s.length; j < jl; j++ ) {
44        gc_result.unshift( s.charAt( j ) );
 47        result.unshift( s.charAt( j ) );
45      }
 48      }
46      return gc_result;
 49      return result;
47    }
 50    }
48    value = value.toString();
 51    value = value.toString();
49    var d_chars = get_chars( split( value ).d.substring( 0, units.length ) );
 52    var r = split( value );
50    console.log( "D:" + d_chars.toString() );
 53    var d_chars = get_chars( r.d.substring( 0, units.length ) );
51    var carry;
 54    //console.log( "D:" + d_chars.toString() );
 55    var carry = 0;
52    for ( var ci = 0, cl = d_chars.length; ci < cl; ci++ ) {
 56    for ( var ci = 0, cl = d_chars.length; ci < cl; ci++ ) {
53      var c = d_chars[ ci ];
 57      var c = d_chars[ ci ];
54      if ( ! /^[0-9]$/.test( c ) ) { break; }
 58      if ( ! /^[0-9]$/.test( c ) ) { break; }
55      if ( ci === 0 ) {
 59      if ( ci === 0 && cl >= units.length ) {
56        carry = Math.round( parseFloat( '0.' + c ) );
 60        carry = Math.round( parseFloat( '0.' + c ) );
57        d_chars[ ci ] = '0';
 61        d_chars[ ci ] = '0';
58      }
 62      }
59      else {
 63      else {
60        var v = parseInt( c ) + carry;
 64        var v = parseInt( c ) + carry;
61        if ( v >= 10 ) {
 65        if ( v >= 10 ) {
62          carry = 1;
 66          carry = 1;
63          v -= 10;
 67          v -= 10;
64        }
 68        }
65        else {
 69        else {
66          carry = 0;
 70          carry = 0;
67        }
 71        }
68        d_chars[ ci ] = v.toString();
 72        d_chars[ ci ] = v.toString();
69      }
 73      }
70    }
 74    }
71    var result = ( parseInt( i ) + carry ).toString() +
 75    var result = ( parseInt( r.i ) + carry ).toString() +
72      array_reverse( d_chars.slice( 0, -1 ) ).join( '' ).replace( /[0.]*$/, '' );
 76      array_reverse( d_chars.slice( 0, -1 ) ).join( '' ).replace( /[0.]*$/, '' );
73    console.log( "N:" + result );
 77    //console.log( "N:" + result );
74    return result;
 78    return result;
75  }
 79  }
76  do {
 80  do {
77    var n = parseInt( read() );
 81    var n = parseInt( read() );
78    //console.log( result );
 82    //console.log( result );
79    result = ( result * Math.pow( 10, read_length ) + n ) % modulus;
 83    result = ( result * Math.pow( 10, read_length ) + n ) % modulus;
80    //var temp = round( result );
 84    var temp = parseFloat( round( result ) );
81    var temp = result;
 85    //console.log( "R:" + result );
82    console.log( "R:" + result );
 86    //console.log( "T:" + temp );
83    console.log( "T:" + temp );
84    if ( ( temp - modulus ) >= 0 ) {
 87    if ( ( temp - modulus ) >= 0 ) {
85      temp -= modulus;
 88      temp -= modulus;
86      console.log( "T:" + temp );
 89      //console.log( "T:" + temp );
 90      result = temp;
87    }
 91    }
88  }
 92  }
89  while ( i.length > 0 );
 93  while ( i.length > 0 );
90  result += parseFloat( d );
 94  result += parseFloat( d );
91  var test = result - modulus;
 95  var test = result - modulus;
92  result = test < 0 ? result : test;
 96  result = test < 0 ? result : test;
93  result = round( result );
 97  result = round( result );
94  console.log( result );
 98  //console.log( result );
95  console.log();
 99  //console.log();
96  return result;
100  return result;