/**
* BC Math Library for Javascript
* Ported from the PHP5 bcmath extension source code,
* which uses the libbcmath package...
* Copyright (C) 1991, 1992, 1993, 1994, 1997 Free Software Foundation, Inc.
* Copyright (C) 2000 Philip A. Nelson
* The Free Software Foundation, Inc.
* 59 Temple Place, Suite 330
* Boston, MA 02111-1307 USA.
* e-mail: philnelson@acm.org
* us-mail: Philip A. Nelson
* Computer Science Department, 9062
* Western Washington University
* Bellingham, WA 98226-9062
*
* bcmath-js homepage:
*
* This code is covered under the LGPL licence, and can be used however you want :)
* Be kind and share any decent code changes.
*/
var libbcmath = {
PLUS: '+',
MINUS: '-',
BASE: 10, // must be 10 (for now)
scale: 0, // default scale
/**
* Basic number structure
*/
bc_num: function() {
this.n_sign = null; // sign
this.n_len = null; /* (int) The number of digits before the decimal point. */
this.n_scale = null; /* (int) The number of digits after the decimal point. */
//this.n_refs = null; /* (int) The number of pointers to this number. */
//this.n_text = null; /* ?? Linked list for available list. */
this.n_value = null; /* array as value, where 1.23 = [1,2,3] */
this.toString = function() {
var r, tmp;
tmp=this.n_value.join('');
// add minus sign (if applicable) then add the integer part
r = ((this.n_sign == libbcmath.PLUS) ? '' : this.n_sign) + tmp.substr(0, this.n_len);
// if decimal places, add a . and the decimal part
if (this.n_scale > 0) {
r += '.' + tmp.substr(this.n_len, this.n_scale);
}
return r;
};
this.setScale = function(newScale) {
while (this.n_scale < newScale) {
this.n_value.push(0);
this.n_scale++;
}
while (this.n_scale > newScale) {
this.n_value.pop();
this.n_scale--;
}
return this;
}
},
/**
* @param int length
* @param int scale
* @return bc_num
*/
bc_new_num: function(length, scale) {
var temp; // bc_num
temp = new libbcmath.bc_num();
temp.n_sign = libbcmath.PLUS;
temp.n_len = length;
temp.n_scale = scale;
temp.n_value = libbcmath.safe_emalloc(1, length+scale, 0);
libbcmath.memset(temp.n_value, 0, 0, length+scale);
return temp;
},
safe_emalloc: function(size, len, extra) {
return Array((size * len) + extra);
},
/**
* Create a new number
*/
bc_init_num: function() {
return new libbcmath.bc_new_num(1,0);
},
_bc_rm_leading_zeros: function (num) {
/* We can move n_value to point to the first non zero digit! */
while ((num.n_value[0] === 0) && (num.n_len > 1)) {
num.n_value.shift();
num.n_len--;
}
},
/**
* Convert to bc_num detecting scale
*/
php_str2num: function(str) {
var p;
p = str.indexOf('.');
if (p==-1) {
return libbcmath.bc_str2num(str, 0);
} else {
return libbcmath.bc_str2num(str, (str.length-p));
}
},
CH_VAL: function(c) {
return c - '0'; //??
},
BCD_CHAR: function(d) {
return d + '0'; // ??
},
isdigit: function(c) {
return (isNaN(parseInt(c,10)) ? false : true);
},
bc_str2num: function(str_in, scale) {
var str,num, ptr, digits, strscale, zero_int, nptr;
// remove any non-expected characters
/* Check for valid number and count digits. */
str=str_in.split(''); // convert to array
ptr = 0; // str
digits = 0;
strscale = 0;
zero_int = false;
if ( (str[ptr] === '+') || (str[ptr] === '-')) {
ptr++; /* Sign */
}
while (str[ptr] === '0') {
ptr++; /* Skip leading zeros. */
}
//while (libbcmath.isdigit(str[ptr])) {
while ((str[ptr]) % 1 === 0) { //libbcmath.isdigit(str[ptr])) {
ptr++;
digits++; /* digits */
}
if (str[ptr] === '.') {
ptr++; /* decimal point */
}
//while (libbcmath.isdigit(str[ptr])) {
while ((str[ptr]) % 1 === 0) { //libbcmath.isdigit(str[ptr])) {
ptr++;
strscale++; /* digits */
}
if ((str[ptr]) || (digits+strscale === 0)) {
// invalid number, return 0
return libbcmath.bc_init_num();
//*num = bc_copy_num (BCG(_zero_));
}
/* Adjust numbers and allocate storage and initialize fields. */
strscale = libbcmath.MIN(strscale, scale);
if (digits === 0) {
zero_int = true;
digits = 1;
}
num = libbcmath.bc_new_num(digits, strscale);
/* Build the whole number. */
ptr = 0; // str
if (str[ptr] === '-') {
num.n_sign = libbcmath.MINUS;
//(*num)->n_sign = MINUS;
ptr++;
} else {
num.n_sign = libbcmath.PLUS;
//(*num)->n_sign = PLUS;
if (str[ptr] === '+') {
ptr++;
}
}
while (str[ptr] === '0') {
ptr++; /* Skip leading zeros. */
}
nptr = 0; //(*num)->n_value;
if (zero_int) {
num.n_value[nptr++] = 0;
digits = 0;
}
for (;digits > 0; digits--) {
num.n_value[nptr++] = libbcmath.CH_VAL(str[ptr++]);
//*nptr++ = CH_VAL(*ptr++);
}
/* Build the fractional part. */
if (strscale > 0) {
ptr++; /* skip the decimal point! */
for (;strscale > 0; strscale--) {
num.n_value[nptr++] = libbcmath.CH_VAL(str[ptr++]);
}
}
return num;
},
cint: function(v) {
if (typeof(v) == 'undefined') {
v = 0;
}
var x=parseInt(v,10);
if (isNaN(x)) {
x = 0;
}
return x;
},
/**
* Basic min function
* @param int
* @param int
*/
MIN: function(a, b) {
return ((a > b) ? b : a);
},
/**
* Basic max function
* @param int
* @param int
*/
MAX: function(a, b) {
return ((a > b) ? a : b);
},
/**
* Basic odd function
* @param int
* @param int
*/
ODD: function(a) {
return (a & 1);
},
/**
* replicate c function
* @param array return (by reference)
* @param string char to fill
* @param int length to fill
*/
memset: function(r, ptr, chr, len) {
var i;
for (i=0;i<len;i++) {
r[ptr+i] = chr;
}
},
/**
* Replacement c function
* Obviously can't work like c does, so we've added an "offset" param so you could do memcpy(dest+1, src, len) as memcpy(dest, 1, src, len)
* Also only works on arrays
*/
memcpy: function(dest, ptr, src, srcptr, len) {
var i;
for (i=0;i<len;i++) {
dest[ptr+i]=src[srcptr+i];
}
return true;
},
/**
* Determine if the number specified is zero or not
* @param bc_num num number to check
* @return boolean true when zero, false when not zero.
*/
bc_is_zero: function(num) {
var count; // int
var nptr; // int
/* Quick check. */
//if (num == BCG(_zero_)) return TRUE;
/* Initialize */
count = num.n_len + num.n_scale;
nptr = 0; //num->n_value;
/* The check */
while ((count > 0) && (num.n_value[nptr++] === 0)) {
count--;
}
if (count !== 0) {
return false;
} else {
return true;
}
},
bc_out_of_memory: function() {
throw new Error("(BC) Out of memory");
}
};
/**
* Base add function
*
// Here is the full add routine that takes care of negative numbers.
// N1 is added to N2 and the result placed into RESULT. SCALE_MIN
// is the minimum scale for the result.
*
* @param bc_num n1
* @param bc_num n2
* @pram int scale_min
* @return bc_num
*/
libbcmath.bc_add = function(n1, n2, scale_min) {
var sum, cmp_res, res_scale;
if (n1.n_sign === n2.n_sign) {
sum = libbcmath._bc_do_add(n1, n2, scale_min);
sum.n_sign = n1.n_sign;
} else {
/* subtraction must be done. */
cmp_res = libbcmath._bc_do_compare(n1, n2, false, false); /* Compare magnitudes. */
switch (cmp_res) {
case -1:
/* n1 is less than n2, subtract n1 from n2. */
sum = libbcmath._bc_do_sub(n2, n1, scale_min);
sum.n_sign = n2.n_sign;
break;
case 0:
/* They are equal! return zero with the correct scale! */
res_scale = libbcmath.MAX(scale_min, libbcmath.MAX(n1.n_scale, n2.n_scale));
sum = libbcmath.bc_new_num(1, res_scale);
libbcmath.memset(sum.n_value, 0, 0, res_scale+1);
break;
case 1:
/* n2 is less than n1, subtract n2 from n1. */
sum = libbcmath._bc_do_sub(n1, n2, scale_min);
sum.n_sign = n1.n_sign;
}
}
return sum;
};
/**
* This is the "user callable" routine to compare numbers N1 and N2.
* @param bc_num n1
* @param bc_num n2
* @return int -1, 0, 1 (n1 < n2, ==, n1 > n2)
*/
libbcmath.bc_compare = function(n1, n2) {
return libbcmath._bc_do_compare (n1, n2, true, false);
};
/**
* @param bc_num n1
* @param bc_num n2
* @param boolean use_sign
* @param boolean ignore_last
* @return -1, 0, 1 (see bc_compare)
*/
libbcmath._bc_do_compare = function(n1, n2, use_sign, ignore_last) {
var n1ptr, n2ptr; // int
var count; // int
/* First, compare signs. */
if (use_sign && (n1.n_sign != n2.n_sign)) {
if (n1.n_sign == libbcmath.PLUS) {
return (1); /* Positive N1 > Negative N2 */
} else {
return (-1); /* Negative N1 < Positive N1 */
}
}
/* Now compare the magnitude. */
if (n1.n_len != n2.n_len) {
if (n1.n_len > n2.n_len) {
/* Magnitude of n1 > n2. */
if (!use_sign || (n1.n_sign == libbcmath.PLUS)) {
return (1);
} else {
return (-1);
}
} else {
/* Magnitude of n1 < n2. */
if (!use_sign || (n1.n_sign == libbcmath.PLUS)) {
return (-1);
} else {
return (1);
}
}
}
/* If we get here, they have the same number of integer digits.
check the integer part and the equal length part of the fraction. */
count = n1.n_len + Math.min(n1.n_scale, n2.n_scale);
n1ptr = 0;
n2ptr = 0;
while ((count > 0) && (n1.n_value[n1ptr] == n2.n_value[n2ptr])) {
n1ptr++;
n2ptr++;
count--;
}
if (ignore_last && (count == 1) && (n1.n_scale == n2.n_scale)) {
return (0);
}
if (count !== 0) {
if (n1.n_value[n1ptr] > n2.n_value[n2ptr]) {
/* Magnitude of n1 > n2. */
if (!use_sign || n1.n_sign == libbcmath.PLUS) {
return (1);
} else {
return (-1);
}
} else {
/* Magnitude of n1 < n2. */
if (!use_sign || n1.n_sign == libbcmath.PLUS) {
return (-1);
} else {
return (1);
}
}
}
/* They are equal up to the last part of the equal part of the fraction. */
if (n1.n_scale != n2.n_scale) {
if (n1.n_scale > n2.n_scale) {
for (count =(n1.n_scale - n2.n_scale); count>0; count--) {
if (n1.n_value[n1ptr++] !== 0) {
/* Magnitude of n1 > n2. */
if (!use_sign || n1.n_sign == libbcmath.PLUS) {
return (1);
} else {
return (-1);
}
}
}
} else {
for (count = (n2.n_scale - n1.n_scale); count>0; count--) {
if (n2.n_value[n2ptr++] !== 0) {
/* Magnitude of n1 < n2. */
if (!use_sign || n1.n_sign == libbcmath.PLUS) {
return (-1);
} else {
return (1);
}
}
}
}
}
/* They must be equal! */
return (0);
};
/* Some utility routines for the divide: First a one digit multiply.
NUM (with SIZE digits) is multiplied by DIGIT and the result is
placed into RESULT. It is written so that NUM and RESULT can be
the same pointers. */
/**
*
* @param array num (pass by ref)
* @param int size
* @param int digit
* @param array result (pass by ref)
*/
libbcmath._one_mult = function(num, n_ptr, size, digit, result, r_ptr) {
var carry, value; // int
var nptr, rptr; // int pointers
if (digit === 0) {
libbcmath.memset(result, 0, 0, size); //memset (result, 0, size);
} else {
if (digit == 1) {
libbcmath.memcpy(result, r_ptr, num, n_ptr, size); //memcpy (result, num, size);
} else {
/* Initialize */
nptr = n_ptr+size-1; //nptr = (unsigned char *) (num+size-1);
rptr = r_ptr+size-1; //rptr = (unsigned char *) (result+size-1);
carry = 0;
while (size-- > 0) {
value = num[nptr--] * digit + carry; //value = *nptr-- * digit + carry;
//result[rptr--] = libbcmath.cint(value % libbcmath.BASE); // @CHECK cint //*rptr-- = value % BASE;
result[rptr--] = value % libbcmath.BASE; // @CHECK cint //*rptr-- = value % BASE;
//carry = libbcmath.cint(value / libbcmath.BASE); // @CHECK cint //carry = value / BASE;
carry = Math.floor(value / libbcmath.BASE); // @CHECK cint //carry = value / BASE;
}
if (carry != 0) {
result[rptr] = carry;
}
}
}
}
/* The full division routine. This computes N1 / N2. It returns
0 if the division is ok and the result is in QUOT. The number of
digits after the decimal point is SCALE. It returns -1 if division
by zero is tried. The algorithm is found in Knuth Vol 2. p237. */
libbcmath.bc_divide = function(n1, n2, scale) {
var quot; // bc_num return
var qval; // bc_num
var num1, num2; // string
var ptr1, ptr2, n2ptr, qptr; // int pointers
var scale1, val; // int
var len1, len2, scale2, qdigits, extra, count; // int
var qdig, qguess, borrow, carry; // int
var mval; // string
var zero; // char
var norm; // int
var ptrs; // return object from one_mul
/* Test for divide by zero. (return failure) */
if (libbcmath.bc_is_zero(n2)) {
return -1;
}
/* Test for zero divide by anything (return zero) */
if (libbcmath.bc_is_zero(n1)) {
return libbcmath.bc_new_num(1, scale);
}
/* Test for n1 equals n2 (return 1 as n1 nor n2 are zero)
if (libbcmath.bc_compare(n1, n2, libbcmath.MAX(n1.n_scale, n2.n_scale)) === 0) {
quot=libbcmath.bc_new_num(1, scale);
quot.n_value[0] = 1;
return quot;
}
*/
/* Test for divide by 1. If it is we must truncate. */
// todo: check where scale > 0 too.. can't see why not (ie bc_is_zero - add bc_is_one function)
if (n2.n_scale === 0) {
if (n2.n_len === 1 && n2.n_value[0] === 1) {
qval = libbcmath.bc_new_num(n1.n_len, scale); //qval = bc_new_num (n1->n_len, scale);
qval.n_sign = (n1.n_sign == n2.n_sign ? libbcmath.PLUS : libbcmath.MINUS);
libbcmath.memset(qval.n_value, n1.n_len, 0, scale); //memset (&qval->n_value[n1->n_len],0,scale);
libbcmath.memcpy(qval.n_value, 0, n1.n_value, 0, n1.n_len + libbcmath.MIN(n1.n_scale, scale)); //memcpy (qval->n_value, n1->n_value, n1->n_len + MIN(n1->n_scale,scale));
// can we return here? not in c src, but can't see why-not.
// return qval;
}
}
/* Set up the divide. Move the decimal point on n1 by n2's scale.
Remember, zeros on the end of num2 are wasted effort for dividing. */
scale2 = n2.n_scale; //scale2 = n2->n_scale;
n2ptr = n2.n_len + scale2 - 1; //n2ptr = (unsigned char *) n2.n_value+n2.n_len+scale2-1;
while ((scale2 > 0) && (n2.n_value[n2ptr--] === 0)) {
scale2--;
}
len1 = n1.n_len + scale2;
scale1 = n1.n_scale - scale2;
if (scale1 < scale) {
extra = scale - scale1;
} else {
extra = 0;
}
num1 = libbcmath.safe_emalloc(1, n1.n_len + n1.n_scale, extra + 2); //num1 = (unsigned char *) safe_emalloc (1, n1.n_len+n1.n_scale, extra+2);
if (num1 === null) {
libbcmath.bc_out_of_memory();
}
libbcmath.memset(num1, 0, 0, n1.n_len+n1.n_scale+extra+2); //memset (num1, 0, n1->n_len+n1->n_scale+extra+2);
libbcmath.memcpy(num1, 1, n1.n_value, 0, n1.n_len+n1.n_scale); //memcpy (num1+1, n1.n_value, n1.n_len+n1.n_scale);
len2 = n2.n_len + scale2; // len2 = n2->n_len + scale2;
num2 = libbcmath.safe_emalloc(1, len2, 1);//num2 = (unsigned char *) safe_emalloc (1, len2, 1);
if (num2 === null) {
libbcmath.bc_out_of_memory();
}
libbcmath.memcpy(num2, 0, n2.n_value, 0, len2); //memcpy (num2, n2.n_value, len2);
num2[len2] = 0; // *(num2+len2) = 0;
n2ptr = 0; //n2ptr = num2;
while (num2[n2ptr] === 0) { // while (*n2ptr == 0)
n2ptr++;
len2--;
}
/* Calculate the number of quotient digits. */
if (len2 > len1+scale) {
qdigits = scale+1;
zero = true;
} else {
zero = false;
if (len2>len1) {
qdigits = scale+1; /* One for the zero integer part. */
} else {
qdigits = len1-len2+scale+1;
}
}
/* Allocate and zero the storage for the quotient. */
qval = libbcmath.bc_new_num(qdigits-scale,scale); //qval = bc_new_num (qdigits-scale,scale);
libbcmath.memset(qval.n_value, 0, 0, qdigits); //memset (qval->n_value, 0, qdigits);
/* Allocate storage for the temporary storage mval. */
mval = libbcmath.safe_emalloc(1, len2, 1); //mval = (unsigned char *) safe_emalloc (1, len2, 1);
if (mval === null) {
libbcmath.bc_out_of_memory();
}
/* Now for the full divide algorithm. */
if (!zero) {
/* Normalize */
//norm = libbcmath.cint(10 / (libbcmath.cint(n2.n_value[n2ptr]) + 1)); //norm = 10 / ((int)*n2ptr + 1);
norm = Math.floor(10 / (n2.n_value[n2ptr] + 1)); //norm = 10 / ((int)*n2ptr + 1);
if (norm != 1) {
libbcmath._one_mult(num1, 0, len1+scale1+extra+1, norm, num1, 0); //libbcmath._one_mult(num1, len1+scale1+extra+1, norm, num1);
libbcmath._one_mult(n2.n_value, n2ptr, len2, norm, n2.n_value, n2ptr); //libbcmath._one_mult(n2ptr, len2, norm, n2ptr);
// @CHECK Is the pointer affected by the call? if so, maybe need to adjust points on return?
}
/* Initialize divide loop. */
qdig = 0;
if (len2 > len1) {
qptr = len2-len1; //qptr = (unsigned char *) qval.n_value+len2-len1;
} else {
qptr = 0; //qptr = (unsigned char *) qval.n_value;
}
/* Loop */
while (qdig <= len1+scale-len2) {
/* Calculate the quotient digit guess. */
if (n2.n_value[n2ptr] == num1[qdig]) {
qguess = 9;
} else {
qguess = Math.floor((num1[qdig]*10 + num1[qdig+1]) / n2.n_value[n2ptr]);
}
/* Test qguess. */
if (n2.n_value[n2ptr+1]*qguess > (num1[qdig]*10 + num1[qdig+1] - n2.n_value[n2ptr]*qguess)*10 + num1[qdig+2]) { //if (n2ptr[1]*qguess > (num1[qdig]*10 + num1[qdig+1] - *n2ptr*qguess)*10 + num1[qdig+2]) {
qguess--;
/* And again. */
if (n2.n_value[n2ptr+1]*qguess > (num1[qdig]*10 + num1[qdig+1] - n2.n_value[n2ptr]*qguess)*10 + num1[qdig+2]) { //if (n2ptr[1]*qguess > (num1[qdig]*10 + num1[qdig+1] - *n2ptr*qguess)*10 + num1[qdig+2])
qguess--;
}
}
/* Multiply and subtract. */
borrow = 0;
if (qguess !== 0) {
mval[0] = 0; //*mval = 0; // @CHECK is this to fix ptr2 < 0?
libbcmath._one_mult(n2.n_value, n2ptr, len2, qguess, mval, 1); //_one_mult (n2ptr, len2, qguess, mval+1); // @CHECK
ptr1 = qdig+len2; //(unsigned char *) num1+qdig+len2;
ptr2 = len2; //(unsigned char *) mval+len2;
// @CHECK: Does a negative pointer return null?
// ptr2 can be < 0 here as ptr1 = len2, thus count < len2+1 will always fail ?
for (count = 0; count < len2+1; count++) {
if (ptr2 < 0) {
//val = libbcmath.cint(num1[ptr1]) - 0 - borrow; //val = (int) *ptr1 - (int) *ptr2-- - borrow;
val = num1[ptr1] - 0 - borrow; //val = (int) *ptr1 - (int) *ptr2-- - borrow;
} else {
//val = libbcmath.cint(num1[ptr1]) - libbcmath.cint(mval[ptr2--]) - borrow; //val = (int) *ptr1 - (int) *ptr2-- - borrow;
val = num1[ptr1] - mval[ptr2--] - borrow; //val = (int) *ptr1 - (int) *ptr2-- - borrow;
}
if (val < 0) {
val += 10;
borrow = 1;
} else {
borrow = 0;
}
num1[ptr1--] = val;
}
}
/* Test for negative result. */
if (borrow == 1) {
qguess--;
ptr1 = qdig+len2; //(unsigned char *) num1+qdig+len2;
ptr2 = len2-1; //(unsigned char *) n2ptr+len2-1;
carry = 0;
for (count = 0; count < len2; count++) {
if (ptr2 < 0) {
//val = libbcmath.cint(num1[ptr1]) + 0 + carry; //val = (int) *ptr1 + (int) *ptr2-- + carry;
val = num1[ptr1] + 0 + carry; //val = (int) *ptr1 + (int) *ptr2-- + carry;
} else {
//val = libbcmath.cint(num1[ptr1]) + libbcmath.cint(n2.n_value[ptr2--]) + carry; //val = (int) *ptr1 + (int) *ptr2-- + carry;
val = num1[ptr1] + n2.n_value[ptr2--] + carry; //val = (int) *ptr1 + (int) *ptr2-- + carry;
}
if (val > 9) {
val -= 10;
carry = 1;
} else {
carry = 0;
}
num1[ptr1--] = val; //*ptr1-- = val;
}
if (carry == 1) {
//num1[ptr1] = libbcmath.cint((num1[ptr1] + 1) % 10); // *ptr1 = (*ptr1 + 1) % 10; // @CHECK
num1[ptr1] = (num1[ptr1] + 1) % 10; // *ptr1 = (*ptr1 + 1) % 10; // @CHECK
}
}
/* We now know the quotient digit. */
qval.n_value[qptr++] = qguess; //*qptr++ = qguess;
qdig++;
}
}
/* Clean up and return the number. */
qval.n_sign = ( n1.n_sign == n2.n_sign ? libbcmath.PLUS : libbcmath.MINUS );
if (libbcmath.bc_is_zero(qval)) {
qval.n_sign = libbcmath.PLUS;
}
libbcmath._bc_rm_leading_zeros(qval);
return qval;
//return 0; /* Everything is OK. */
};
/**
* Perform an "add"
*
// Perform addition: N1 is added to N2 and the value is
// returned. The signs of N1 and N2 are ignored.
// SCALE_MIN is to set the minimum scale of the result.
*
* Basic school maths says to add 2 numbers..
* 1. make them the same length, the decimal places, and the integer part
* 2. start from the right and add the two numbers together
* 3. if the sum of the 2 numbers > 9, carry 1 to the next set and subtract 10 (ie 18 > carry 1 becomes 8). thus 0.9 + 0.9 = 1.8
*
* @param bc_num n1
* @param bc_num n2
* @param int scale_min
* @return bc_num
*/
libbcmath._bc_do_add = function(n1, n2, scale_min) {
var sum; // bc_num
var sum_scale, sum_digits; // int
var n1ptr, n2ptr, sumptr; // int
var carry, n1bytes, n2bytes; // int
var tmp; // int
// Prepare sum.
sum_scale = libbcmath.MAX(n1.n_scale, n2.n_scale);
sum_digits = libbcmath.MAX(n1.n_len, n2.n_len) + 1;
sum = libbcmath.bc_new_num(sum_digits, libbcmath.MAX(sum_scale, scale_min));
/* Not needed?
if (scale_min > sum_scale) {
sumptr = (char *) (sum->n_value + sum_scale + sum_digits);
for (count = scale_min - sum_scale; count > 0; count--) {
*sumptr++ = 0;
}
}
*/
// Start with the fraction part. Initialize the pointers.
n1bytes = n1.n_scale;
n2bytes = n2.n_scale;
n1ptr = (n1.n_len + n1bytes - 1);
n2ptr = (n2.n_len + n2bytes - 1);
sumptr = (sum_scale + sum_digits - 1);
// Add the fraction part. First copy the longer fraction (ie when adding 1.2345 to 1 we know .2345 is correct already) .
if (n1bytes != n2bytes) {
if (n1bytes > n2bytes) {
// n1 has more dp then n2
while (n1bytes>n2bytes) {
sum.n_value[sumptr--] = n1.n_value[n1ptr--];
// *sumptr-- = *n1ptr--;
n1bytes--;
}
} else {
// n2 has more dp then n1
while (n2bytes>n1bytes) {
sum.n_value[sumptr--] = n2.n_value[n2ptr--];
// *sumptr-- = *n2ptr--;
n2bytes--;
}
}
}
// Now add the remaining fraction part and equal size integer parts.
n1bytes += n1.n_len;
n2bytes += n2.n_len;
carry = 0;
while ((n1bytes > 0) && (n2bytes > 0)) {
// add the two numbers together
tmp = n1.n_value[n1ptr--] + n2.n_value[n2ptr--] + carry;
// *sumptr = *n1ptr-- + *n2ptr-- + carry;
// check if they are >= 10 (impossible to be more then 18)
if (tmp >= libbcmath.BASE) {
carry = 1;
tmp -= libbcmath.BASE; // yep, subtract 10, add a carry
} else {
carry = 0;
}
sum.n_value[sumptr] = tmp;
sumptr--;
n1bytes--;
n2bytes--;
}
// Now add carry the [rest of the] longer integer part.
if (n1bytes === 0) {
// n2 is a bigger number then n1
while (n2bytes-- > 0) {
tmp = n2.n_value[n2ptr--] + carry;
// *sumptr = *n2ptr-- + carry;
if (tmp >= libbcmath.BASE) {
carry = 1;
tmp -= libbcmath.BASE;
} else {
carry = 0;
}
sum.n_value[sumptr--]=tmp;
}
} else {
// n1 is bigger then n2..
while (n1bytes-- > 0) {
tmp = n1.n_value[n1ptr--] + carry;
// *sumptr = *n1ptr-- + carry;
if (tmp >= libbcmath.BASE) {
carry = 1;
tmp -= libbcmath.BASE;
} else {
carry = 0;
}
sum.n_value[sumptr--]=tmp;
}
}
// Set final carry.
if (carry == 1) {
sum.n_value[sumptr] += 1;
// *sumptr += 1;
}
// Adjust sum and return.
libbcmath._bc_rm_leading_zeros (sum);
return sum;
};
/**
* Perform a subtraction
*
// Perform subtraction: N2 is subtracted from N1 and the value is
// returned. The signs of N1 and N2 are ignored. Also, N1 is
// assumed to be larger than N2. SCALE_MIN is the minimum scale
// of the result.
*
* Basic school maths says to subtract 2 numbers..
* 1. make them the same length, the decimal places, and the integer part
* 2. start from the right and subtract the two numbers from each other
* 3. if the sum of the 2 numbers < 0, carry -1 to the next set and add 10 (ie 18 > carry 1 becomes 8). thus 0.9 + 0.9 = 1.8
*
* @param bc_num n1
* @param bc_num n2
* @param int scale_min
* @return bc_num
*/
libbcmath._bc_do_sub = function(n1, n2, scale_min) {
var diff; //bc_num
var diff_scale, diff_len; // int
var min_scale, min_len; // int
var n1ptr, n2ptr, diffptr; // int
var borrow, count, val; // int
// Allocate temporary storage.
diff_len = libbcmath.MAX(n1.n_len, n2.n_len);
diff_scale = libbcmath.MAX(n1.n_scale, n2.n_scale);
min_len = libbcmath.MIN(n1.n_len, n2.n_len);
min_scale = libbcmath.MIN(n1.n_scale, n2.n_scale);
diff = libbcmath.bc_new_num(diff_len, libbcmath.MAX(diff_scale, scale_min));
/* Not needed?
// Zero extra digits made by scale_min.
if (scale_min > diff_scale) {
diffptr = (char *) (diff->n_value + diff_len + diff_scale);
for (count = scale_min - diff_scale; count > 0; count--) {
*diffptr++ = 0;
}
}
*/
// Initialize the subtract.
n1ptr = (n1.n_len + n1.n_scale -1);
n2ptr = (n2.n_len + n2.n_scale -1);
diffptr = (diff_len + diff_scale -1);
// Subtract the numbers.
borrow = 0;
// Take care of the longer scaled number.
if (n1.n_scale != min_scale) {
// n1 has the longer scale
for (count = n1.n_scale - min_scale; count > 0; count--) {
diff.n_value[diffptr--] = n1.n_value[n1ptr--];
// *diffptr-- = *n1ptr--;
}
} else {
// n2 has the longer scale
for (count = n2.n_scale - min_scale; count > 0; count--) {
val = 0 - n2.n_value[n2ptr--] - borrow;
//val = - *n2ptr-- - borrow;
if (val < 0) {
val += libbcmath.BASE;
borrow = 1;
} else {
borrow = 0;
diff.n_value[diffptr--] = val;
//*diffptr-- = val;
}
}
}
// Now do the equal length scale and integer parts.
for (count = 0; count < min_len + min_scale; count++) {
val = n1.n_value[n1ptr--] - n2.n_value[n2ptr--] - borrow;
//val = *n1ptr-- - *n2ptr-- - borrow;
if (val < 0) {
val += libbcmath.BASE;
borrow = 1;
} else {
borrow = 0;
}
diff.n_value[diffptr--] = val;
//*diffptr-- = val;
}
// If n1 has more digits then n2, we now do that subtract.
if (diff_len != min_len) {
for (count = diff_len - min_len; count > 0; count--) {
val = n1.n_value[n1ptr--] - borrow;
// val = *n1ptr-- - borrow;
if (val < 0) {
val += libbcmath.BASE;
borrow = 1;
} else {
borrow = 0;
}
diff.n_value[diffptr--] = val;
}
}
// Clean up and return.
libbcmath._bc_rm_leading_zeros(diff);
return diff;
};
libbcmath.MUL_BASE_DIGITS = 80;
libbcmath.MUL_SMALL_DIGITS = (libbcmath.MUL_BASE_DIGITS / 4); //#define MUL_SMALL_DIGITS mul_base_digits/4
/* The multiply routine. N2 times N1 is put int PROD with the scale of
the result being MIN(N2 scale+N1 scale, MAX (SCALE, N2 scale, N1 scale)).
*/
/**
* @param n1 bc_num
* @param n2 bc_num
* @param scale [int] optional
*/
libbcmath.bc_multiply = function(n1, n2, scale) {
var pval; // bc_num
var len1, len2; // int
var full_scale, prod_scale; // int
// Initialize things.
len1 = n1.n_len + n1.n_scale;
len2 = n2.n_len + n2.n_scale;
full_scale = n1.n_scale + n2.n_scale;
prod_scale = libbcmath.MIN(full_scale,libbcmath.MAX(scale,libbcmath.MAX(n1.n_scale, n2.n_scale)));
//pval = libbcmath.bc_init_num(); // allow pass by ref
// Do the multiply
pval = libbcmath._bc_rec_mul (n1, len1, n2, len2, full_scale);
// Assign to prod and clean up the number.
pval.n_sign = ( n1.n_sign == n2.n_sign ? libbcmath.PLUS : libbcmath.MINUS );
//pval.n_value = pval.n_ptr; // @FIX
pval.n_len = len2 + len1 + 1 - full_scale;
pval.n_scale = prod_scale;
libbcmath._bc_rm_leading_zeros(pval);
if (libbcmath.bc_is_zero(pval)) {
pval.n_sign = libbcmath.PLUS;
}
//bc_free_num (prod);
return pval;
};
libbcmath.new_sub_num = function(length, scale, value) {
var temp = new libbcmath.bc_num();
temp.n_sign = libbcmath.PLUS;
temp.n_len = length;
temp.n_scale = scale;
temp.n_value = value;
return temp;
};
libbcmath._bc_simp_mul = function(n1, n1len, n2, n2len, full_scale) {
var prod; // bc_num
var n1ptr, n2ptr, pvptr; // char *n1ptr, *n2ptr, *pvptr;
var n1end, n2end; //char *n1end, *n2end; /* To the end of n1 and n2. */
var indx, sum, prodlen; //int indx, sum, prodlen;
prodlen = n1len+n2len+1;
prod = libbcmath.bc_new_num(prodlen, 0);
n1end = n1len-1; //(char *) (n1->n_value + n1len - 1);
n2end = n2len-1; //(char *) (n2->n_value + n2len - 1);
pvptr = prodlen-1; //(char *) ((*prod)->n_value + prodlen - 1);
sum = 0;
// Here is the loop...
for (indx = 0; indx < prodlen-1; indx++) {
n1ptr = n1end - libbcmath.MAX(0, indx-n2len+1); //(char *) (n1end - MAX(0, indx-n2len+1));
n2ptr = n2end - libbcmath.MIN(indx, n2len-1); //(char *) (n2end - MIN(indx, n2len-1));
while ((n1ptr >= 0) && (n2ptr <= n2end)) {
sum += n1.n_value[n1ptr--] * n2.n_value[n2ptr++]; //sum += *n1ptr-- * *n2ptr++;
}
prod.n_value[pvptr--] = Math.floor(sum % libbcmath.BASE); //*pvptr-- = sum % BASE;
sum = Math.floor(sum / libbcmath.BASE); //sum = sum / BASE;
}
prod.n_value[pvptr]=sum; //*pvptr = sum;
return prod;
};
/* A special adder/subtractor for the recursive divide and conquer
multiply algorithm. Note: if sub is called, accum must
be larger that what is being subtracted. Also, accum and val
must have n_scale = 0. (e.g. they must look like integers. *) */
libbcmath._bc_shift_addsub = function(accum, val, shift, sub) {
var accp, valp; //signed char *accp, *valp;
var count, carry; //int count, carry;
count = val.n_len;
if (val.n_value[0] === 0) {
count--;
}
//assert (accum->n_len+accum->n_scale >= shift+count);
if (!(accum.n_len+accum.n_scale >= shift+count)) {
throw new Error("len + scale < shift + count"); // ?? I think thats what assert does :)
}
// Set up pointers and others
accp = accum.n_len + accum.n_scale - shift - 1; // (signed char *)(accum->n_value + accum->n_len + accum->n_scale - shift - 1);
valp = val.n_len = 1; //(signed char *)(val->n_value + val->n_len - 1);
carry = 0;
if (sub) {
// Subtraction, carry is really borrow.
while (count--) {
accum.n_value[accp] -= val.n_value[valp--] + carry; //*accp -= *valp-- + carry;
if (accum.n_value[accp] < 0) { //if (*accp < 0)
carry = 1;
accum.n_value[accp--] += libbcmath.BASE; //*accp-- += BASE;
} else {
carry = 0;
accp--;
}
}
while (carry) {
accum.n_value[accp] -= carry; //*accp -= carry;
if (accum.n_value[accp] < 0) { //if (*accp < 0)
accum.n_value[accp--] += libbcmath.BASE; // *accp-- += BASE;
} else {
carry = 0;
}
}
} else {
// Addition
while (count--) {
accum.n_value[accp] += val.n_value[valp--] + carry; //*accp += *valp-- + carry;
if (accum.n_value[accp] > (libbcmath.BASE-1)) {//if (*accp > (BASE-1))
carry = 1;
accum.n_value[accp--] -= libbcmath.BASE; //*accp-- -= BASE;
} else {
carry = 0;
accp--;
}
}
while (carry) {
accum.n_value[accp] += carry; //*accp += carry;
if (accum.n_value[accp] > (libbcmath.BASE-1)) { //if (*accp > (BASE-1))
accum.n_value[accp--] -= libbcmath.BASE; //*accp-- -= BASE;
} else {
carry = 0;
}
}
}
return true; // accum is the pass-by-reference return
};
/* Recursive divide and conquer multiply algorithm.
Based on
Let u = u0 + u1*(b^n)
Let v = v0 + v1*(b^n)
Then uv = (B^2n+B^n)*u1*v1 + B^n*(u1-u0)*(v0-v1) + (B^n+1)*u0*v0
B is the base of storage, number of digits in u1,u0 close to equal.
*/
libbcmath._bc_rec_mul = function (u, ulen, v, vlen, full_scale) {
var prod; // @return
var u0, u1, v0, v1; //bc_num
var u0len, v0len; //int
var m1, m2, m3, d1, d2; //bc_num
var n, prodlen, m1zero; // int
var d1len, d2len; // int
// Base case?
if ( (ulen+vlen) < libbcmath.MUL_BASE_DIGITS || ulen < libbcmath.MUL_SMALL_DIGITS || vlen < libbcmath.MUL_SMALL_DIGITS ) {
return libbcmath._bc_simp_mul(u, ulen, v, vlen, full_scale);
}
// Calculate n -- the u and v split point in digits.
n = Math.floor((libbcmath.MAX(ulen, vlen)+1) / 2);
// Split u and v.
if (ulen < n) {
u1 = libbcmath.bc_init_num(); //u1 = bc_copy_num (BCG(_zero_));
u0 = libbcmath.new_sub_num(ulen,0, u.n_value);
} else {
u1 = libbcmath.new_sub_num(ulen-n, 0, u.n_value);
u0 = libbcmath.new_sub_num(n, 0, u.n_value+ulen-n);
}
if (vlen < n) {
v1 = libbcmath.bc_init_num(); //bc_copy_num (BCG(_zero_));
v0 = libbcmath.new_sub_num(vlen,0, v.n_value);
} else {
v1 = libbcmath.new_sub_num(vlen-n, 0, v.n_value);
v0 = libbcmath.new_sub_num(n, 0, v.n_value+vlen-n);
}
libbcmath._bc_rm_leading_zeros(u1);
libbcmath._bc_rm_leading_zeros(u0);
u0len = u0.n_len;
libbcmath._bc_rm_leading_zeros(v1);
libbcmath._bc_rm_leading_zeros(v0);
v0len = v0.n_len;
m1zero = libbcmath.bc_is_zero(u1) || libbcmath.bc_is_zero(v1);
// Calculate sub results ...
d1 = libbcmath.bc_init_num(); // needed?
d2 = libbcmath.bc_init_num(); // needed?
d1 = libbcmath.bc_sub(u1, u0, 0);
d1len = d1.n_len;
d2 = libbcmath.bc_sub (v0, v1, 0);
d2len = d2.n_len;
// Do recursive multiplies and shifted adds.
if (m1zero) {
m1 = libbcmath.bc_init_num(); //bc_copy_num (BCG(_zero_));
} else {
//m1 = libbcmath.bc_init_num(); //allow pass-by-ref
m1 = libbcmath._bc_rec_mul (u1, u1.n_len, v1, v1.n_len, 0);
}
if (libbcmath.bc_is_zero(d1) || libbcmath.bc_is_zero(d2)) {
m2 = libbcmath.bc_init_num(); //bc_copy_num (BCG(_zero_));
} else {
//m2 = libbcmath.bc_init_num(); //allow pass-by-ref
m2 = libbcmath._bc_rec_mul (d1, d1len, d2, d2len, 0);
}
if (libbcmath.bc_is_zero(u0) || libbcmath.bc_is_zero(v0)) {
m3 = libbcmath.bc_init_num(); //bc_copy_num (BCG(_zero_));
} else {
//m3 = libbcmath.bc_init_num(); //allow pass-by-ref
m3 = libbcmath._bc_rec_mul(u0, u0.n_len, v0, v0.n_len, 0);
}
// Initialize product
prodlen = ulen+vlen+1;
prod = libbcmath.bc_new_num(prodlen, 0);
if (!m1zero) {
libbcmath._bc_shift_addsub(prod, m1, 2*n, 0);
libbcmath._bc_shift_addsub(prod, m1, n, 0);
}
libbcmath._bc_shift_addsub(prod, m3, n, 0);
libbcmath._bc_shift_addsub(prod, m3, 0, 0);
libbcmath._bc_shift_addsub(prod, m2, n, d1.n_sign != d2.n_sign);
return prod;
// Now clean up!
//bc_free_num (&u1);
//bc_free_num (&u0);
//bc_free_num (&v1);
//bc_free_num (&m1);
//bc_free_num (&v0);
//bc_free_num (&m2);
//bc_free_num (&m3);
//bc_free_num (&d1);
//bc_free_num (&d2);
};
/* Here is the full subtract routine that takes care of negative numbers.
N2 is subtracted from N1 and the result placed in RESULT. SCALE_MIN
is the minimum scale for the result. */
libbcmath.bc_sub = function(n1, n2, scale_min) {
var diff; // bc_num
var cmp_res, res_scale; //int
if (n1.n_sign != n2.n_sign) {
diff = libbcmath._bc_do_add (n1, n2, scale_min);
diff.n_sign = n1.n_sign;
} else {
/* subtraction must be done. */
/* Compare magnitudes. */
cmp_res = libbcmath._bc_do_compare(n1, n2, false, false);
switch (cmp_res) {
case -1:
/* n1 is less than n2, subtract n1 from n2. */
diff = libbcmath._bc_do_sub(n2, n1, scale_min);
diff.n_sign = (n2.n_sign == libbcmath.PLUS ? libbcmath.MINUS : libbcmath.PLUS);
break;
case 0:
/* They are equal! return zero! */
res_scale = libbcmath.MAX(scale_min, libbcmath.MAX(n1.n_scale, n2.n_scale));
diff = libbcmath.bc_new_num(1, res_scale);
libbcmath.memset(diff.n_value, 0, 0, res_scale+1);
break;
case 1:
/* n2 is less than n1, subtract n2 from n1. */
diff = libbcmath._bc_do_sub(n1, n2, scale_min);
diff.n_sign = n1.n_sign;
break;
}
}
/* Clean up and return. */
//bc_free_num (result);
//*result = diff;
return diff;
};
/**
* PHP Implementation of the libbcmath functions
*
* Designed to replicate the PHP functions exactly.
* Also includes new function: bcround
*/
/**
* bcadd - Add two arbitrary precision numbers
* Sums left_operand and right_operand.
*
* @param string left_operand The left operand, as a string
* @param string right_operand The right operand, as a string.
* @param int [scale] The optional parameter is used to set the number of digits after the decimal place in the result. You can also set the global scale for all functions by using bcscale()
* @return string
*/
function bcadd(left_operand, right_operand, scale) {
var first, second, result;
if (typeof(scale) == 'undefined') {
scale = libbcmath.scale;
}
scale = ((scale < 0) ? 0 : scale);
// create objects
first = libbcmath.bc_init_num();
second = libbcmath.bc_init_num();
result = libbcmath.bc_init_num();
first = libbcmath.php_str2num(left_operand.toString());
second = libbcmath.php_str2num(right_operand.toString());
// normalize arguments to same scale.
if (first.n_scale > second.n_scale) second.setScale(first.n_scale);
if (second.n_scale > first.n_scale) first.setScale(second.n_scale);
result = libbcmath.bc_add(first, second, scale);
if (result.n_scale > scale) {
result.n_scale = scale;
}
return result.toString();
}
/**
* bcsub - Subtract one arbitrary precision number from another
* Returns difference between the left operand and the right operand.
*
* @param string left_operand The left operand, as a string
* @param string right_operand The right operand, as a string.
* @param int [scale] The optional parameter is used to set the number of digits after the decimal place in the result. You can also set the global scale for all functions by using bcscale()
* @return string
*/
function bcsub(left_operand, right_operand, scale) {
var first, second, result;
if (typeof(scale) == 'undefined') {
scale = libbcmath.scale;
}
scale = ((scale < 0) ? 0 : scale);
// create objects
first = libbcmath.bc_init_num();
second = libbcmath.bc_init_num();
result = libbcmath.bc_init_num();
first = libbcmath.php_str2num(left_operand.toString());
second = libbcmath.php_str2num(right_operand.toString());
// normalize arguments to same scale.
if (first.n_scale > second.n_scale) second.setScale(first.n_scale);
if (second.n_scale > first.n_scale) first.setScale(second.n_scale);
result = libbcmath.bc_sub(first, second, scale);
if (result.n_scale > scale) {
result.n_scale = scale;
}
return result.toString();
}
/**
* bccomp - Compare two arbitrary precision numers
*
* @param string left_operand The left operand, as a string
* @param string right_operand The right operand, as a string.
* @param int [scale] The optional parameter is used to set the number of digits after the decimal place in the result. You can also set the global scale for all functions by using bcscale()
* @return int 0: Left/Right are equal, 1 if left > right, -1 otherwise
*/
function bccomp(left_operand, right_operand, scale) {
var first, second; //bc_num
if (typeof(scale) == 'undefined') {
scale = libbcmath.scale;
}
scale = ((scale < 0) ? 0 : scale);
first = libbcmath.bc_init_num();
second = libbcmath.bc_init_num();
first = libbcmath.bc_str2num(left_operand.toString(), scale); // note bc_ not php_str2num
second = libbcmath.bc_str2num(right_operand.toString(), scale); // note bc_ not php_str2num
return libbcmath.bc_compare(first, second, scale);
}
/**
* bcscale - Set default scale parameter for all bc math functions
* @param int scale The scale factor (0 to infinate)
* @return bool
*/
function bcscale(scale) {
scale = parseInt(scale, 10);
if (isNaN(scale)) {
return false;
}
if (scale < 0) {
return false;
}
libbcmath.scale = scale;
return true;
}
/**
* bcdiv - Divide two arbitrary precision numbers
*
* @param string left_operand The left operand, as a string
* @param string right_operand The right operand, as a string.
* @param int [scale] The optional parameter is used to set the number of digits after the decimal place in the result. You can also set the global scale for all functions by using bcscale()
* @return string The result as a string
*/
function bcdiv(left_operand, right_operand, scale) {
var first, second, result;
if (typeof(scale) == 'undefined') {
scale = libbcmath.scale;
}
scale = ((scale < 0) ? 0 : scale);
// create objects
first = libbcmath.bc_init_num();
second = libbcmath.bc_init_num();
result = libbcmath.bc_init_num();
first = libbcmath.php_str2num(left_operand.toString());
second = libbcmath.php_str2num(right_operand.toString());
// normalize arguments to same scale.
if (first.n_scale > second.n_scale) second.setScale(first.n_scale);
if (second.n_scale > first.n_scale) first.setScale(second.n_scale);
result = libbcmath.bc_divide(first, second, scale);
if (result === -1) {
// error
throw new Error(11, "(BC) Division by zero");
}
if (result.n_scale > scale) {
result.n_scale = scale;
}
return result.toString();
}
/**
* bcdiv - Multiply two arbitrary precision number
*
* @param string left_operand The left operand, as a string
* @param string right_operand The right operand, as a string.
* @param int [scale] The optional parameter is used to set the number of digits after the decimal place in the result. You can also set the global scale for all functions by using bcscale()
* @return string The result as a string
*/
function bcmul(left_operand, right_operand, scale) {
var first, second, result;
if (typeof(scale) == 'undefined') {
scale = libbcmath.scale;
}
scale = ((scale < 0) ? 0 : scale);
// create objects
first = libbcmath.bc_init_num();
second = libbcmath.bc_init_num();
result = libbcmath.bc_init_num();
first = libbcmath.php_str2num(left_operand.toString());
second = libbcmath.php_str2num(right_operand.toString());
// normalize arguments to same scale.
if (first.n_scale > second.n_scale) second.setScale(first.n_scale);
if (second.n_scale > first.n_scale) first.setScale(second.n_scale);
result = libbcmath.bc_multiply(first, second, scale);
if (result.n_scale > scale) {
result.n_scale = scale;
}
return result.toString();
}
/**
* bcround - Returns the rounded value of [val] to the specified [precision] (number of digits after the decimal point).
* [precision] can also be a negative or zero (default)
* Note: uses "round up and away from zero" method (ie -1.5 > -2, 1.5 > 2 where .5 always goes to 1 (or 0.5 to -1) etc
*
* @param string val The value to round (accept in virtually any format)
* @param int precision The optional number of digits to round-to
* @return string In exact decimal places of precision (ie bcround('1.2222', 2) == '1.22' or bcround('1', 4) == '1.0000' )
*/
function bcround(val, precision) {
var x, r;
x = '0.' + Array(precision+1).join('0') + '5';
if (val.toString().substring(0, 1) == '-') {
x = '-' + x;
}
r = bcadd(val, x, precision);
return r;
}
/*
var temp, result, digit;
var right_operand;
// create number
temp = libbcmath.bc_init_num();
temp = libbcmath.php_str2num(val.toString());
// check if any rounding needs
if (precision >= temp.n_scale) {
// nothing to round, just add the zeros.
while (temp.n_scale < precision) {
temp.n_value[temp.n_len+temp.n_scale]=0;
temp.n_scale++;
}
return temp.toString();
}
// get the digit we are checking (1 after the precision)
// loop through digits after the precision marker
digit = temp.n_value[temp.n_len + precision];
right_operand = libbcmath.bc_init_num();
right_operand = libbcmath.bc_new_num(1, precision);
if (digit >= 5) {
//round away from zero by adding 1 (or -1) at the "precision".. ie 1.44999 @ 3dp = (1.44999 + 0.001).toString().substr(0,5)
right_operand.n_value[right_operand.n_len+right_operand.n_scale-1] = 1;
if (temp.n_sign == libbcmath.MINUS) {
// round down
right_operand.n_sign = libbcmath.MINUS;
}
result = libbcmath.bc_add(temp, right_operand, precision);
} else {
// leave-as-is.. just truncate it.
result = temp;
}
if (result.n_scale > precision) {
result.n_scale = precision;
}
return result.toString();
} */
/**
* Decimal Number Object
*
* Designed to be an OO Number Object to replace basic mathematics in JavaScript
* Requires the "bcmath" javascript library (https://sourceforge.net/projects/bcmath-js - see "bcmath-min.js")
* Licence is BSD licence, bcmath is LGPL
*
* Example: var x=new DecimalNumber('123.456', 3); // create 3dp number, any operations will be calculated then rounded to 3dp
* x.add('5'); // add 5 to our number
* x.sub('5').mul('5'); // subtract 5, then multiply by 5
* alert(x); // display the number (can also use x.toString() if needed)
*
* Arguements can be passed in formula method too (but are applicable to std floating point errors).. ie:
* x = new DecimalNumber('5+5', 2);
* x.add('3/4');
* x.toString(); // returns 10.75
*/
function DecimalNumber(num, precision) {
if (typeof(precision) == 'undefined') {
precision = 0;
}
if (typeof(num) == 'undefined') {
num = '0';
}
this.getPi = function(precision) {
if (precision > 37) {
alert('Note: this approximation is not accurate above 37 decimal places');
}
return bcdiv('2646693125139304345', '842468587426513207', precision);
};
this.toString = function() {
return this._result;
};
this.floor = function(precision) {
this._result = bcadd(this._result, '0', 0);
return this;
};
this.ceil = function(precision) {
if (this._result.substr(0, 1) == '-') {
this._result = bcround(bcadd(this._result, '-0.5', 1), 0);
} else {
this._result = bcround(bcadd(this._result, '0.5', 1), 0);
}
return this;
};
this.toFixed = function(precision) {
return bcround(this._result, precision);
};
this.valueOf = function() {
return this._result;
};
this.abs = function() {
if (this._result.substr(0, 1) == '-') {
this._result = this._result.substr(1, this._result.length-1);
};
return this;
};
this.toInt = function() {
return parseInt(this.toFixed(0));
};
this.toFloat = function() {
return parseFloat(this._result);
};
this.add = function(operand) {
this._result = bcround(bcadd(this._result, this._parseNumber(operand), this._precision+2), this._precision);
return this;
};
this.sub = function(operand) {
return this.subtract(operand);
};
this.subtract = function(operand) {
this._result = bcround(bcsub(this._result, this._parseNumber(operand), this._precision+2), this._precision);
return this;
};
this.mul = function(operand) {
return this.multiply(operand);
};
this.multiply = function(operand) {
this._result = bcround(bcmul(this._result, this._parseNumber(operand), this._precision+2), this._precision);
return this;
};
this.div = function(operand) {
return this.divide(operand);
};
this.divide = function(operand) {
this._result = bcround(bcdiv(this._result, this._parseNumber(operand), this._precision+2), this._precision);
return this;
};
this.round = function(precision) {
this._result = bcround(this._result, precision);
return this;
};
this.setPrecision=function(precision) {
this._precision = precision;
this.round(precision);
return this;
};
this._parseNumber=function(num) {
var tmp, r;
tmp = num.toString().replace(/[^0-9\-\.]/g,'');
if (tmp === '') {
return '0';
}
return tmp;
};
this.reset = function(num) {
if (typeof(num) == 'undefined') {
num = 0;
}
this._result = bcround(num, this._precision);
return this;
}
// construct
this._precision = precision;
this._result = bcround(this._parseNumber(num), this._precision);
};
/**
* So why do we need DecimalNumber?
* Answer: Math.floor((0.1+0.7)*10) being one example.. (returns 7, should be 8)
* As the PHP Manual says... "http://nz.php.net/manual/en/language.types.float.php"
* "This is due to the fact that it is impossible to express some
* fractions in decimal notation with a finite number of digits.
* For instance, 1/3 in decimal form becomes 0.3."
*/
function TestFloatingPointProblems() {
// First, lets try JavaScripts Built-in maths...
var x=0;
x += 0.1;
x += 0.7;
x = x * 10;
x = Math.floor(x).toString();
if (x === '8') {
alert("Wow! Result is correct, your browser doesn't have the floating point problems... cool :)");
} else {
alert("Well, apparently your browser can't work out Floor((0.1 + 0.7) * 10).. it thinks the answer is: " + x + ", the correct answer is of course 8.");
}
var y=new DecimalNumber(0, 1)
.add('0.1').add('0.7')
.multiply('10')
.floor()
.toString()
;
if (y === '8') {
alert('Howver, The DecimalNumber Library worked it out fine.. it figured out the maths as expected :)');
} else {
alert("Odd, apparently the DecimalNumber library can't work it out either.. must be a problem somewhere :/");
}
// now let's test PI using a magic number... http://qin.laya.com/tech_projects_approxpi.html
var browserPi=(2646693125139304345/842468587426513207).toFixed(20); // as high as it goes
if (browserPi == '3.14159265358979323846') {//264338327950288418
alert('Your browser calculates PI correctly to 20dp.. well done');
} else {
alert('Your browser calculates PI WRONG.. it is.. ' + bcsub('3.14159265358979323846', browserPi, 20) + ' off at 20dp');
}
var decNumPi=new DecimalNumber(0, 20);
decNumPi = decNumPi.reset('2646693125139304345').divide('842468587426513207').toString(); //getPi(20);
if (decNumPi == '3.14159265358979323846') {//264338327950288418
alert('The DecimalNumber Library calculates PI correctly to 20dp... of course :)');
} else {
alert('Odd, the DecimalNumber Library calculated PI WRONG.. it is..' + bcsub('3.14159265358979323846', browserPi, 20) + ' off at 20dp');
}
// heck, lets go all out.. test at 38dp (limit of the accuracy of the 2 numbers to PI)..
var decNumPi=new DecimalNumber(0, 38);
decNumPi = decNumPi.reset('2646693125139304345').divide('842468587426513207').toString(); //getPi(20);
if (decNumPi == '3.14159265358979323846264338327950288418') {
alert('The DecimalNumber Library calculates PI correctly to 38dp... of course :)');
} else {
alert('Odd, the DecimalNumber Library calculated PI WRONG.. it is..' + bcsub('3.14159265358979323846264338327950288418', decNumPi, 38) + ' off at 38dp');
}
var decNumPi=new DecimalNumber();
decNumPi.getPi(1000000);
decNumPi = null;
alert('done');
};
