[perl5.git] / lib / bigint.pl

package bigint;
#
# This library is no longer being maintained, and is included for backward
# compatibility with Perl 4 programs which may require it.
#
# In particular, this should not be used as an example of modern Perl
# programming techniques.
#
# Suggested alternative:  Math::BigInt
#
# arbitrary size integer math package
#
# by Mark Biggar
#
# Canonical Big integer value are strings of the form
#       /^[+-]\d+$/ with leading zeros suppressed
# Input values to these routines may be strings of the form
#       /^\s*[+-]?[\d\s]+$/.
# Examples:
#   '+0'                            canonical zero value
#   '   -123 123 123'               canonical value '-123123123'
#   '1 23 456 7890'                 canonical value '+1234567890'
# Output values always always in canonical form
#
# Actual math is done in an internal format consisting of an array
#   whose first element is the sign (/^[+-]$/) and whose remaining 
#   elements are base 100000 digits with the least significant digit first.
# The string 'NaN' is used to represent the result when input arguments 
#   are not numbers, as well as the result of dividing by zero
#
# routines provided are:
#
#   bneg(BINT) return BINT              negation
#   babs(BINT) return BINT              absolute value
#   bcmp(BINT,BINT) return CODE         compare numbers (undef,<0,=0,>0)
#   badd(BINT,BINT) return BINT         addition
#   bsub(BINT,BINT) return BINT         subtraction
#   bmul(BINT,BINT) return BINT         multiplication
#   bdiv(BINT,BINT) return (BINT,BINT)  division (quo,rem) just quo if scalar
#   bmod(BINT,BINT) return BINT         modulus
#   bgcd(BINT,BINT) return BINT         greatest common divisor
#   bnorm(BINT) return BINT             normalization
#

$zero = 0;

\f
# normalize string form of number.   Strip leading zeros.  Strip any
#   white space and add a sign, if missing.
# Strings that are not numbers result the value 'NaN'.

sub main'bnorm { #(num_str) return num_str
    local($_) = @_;
    s/\s+//g;                           # strip white space
    if (s/^([+-]?)0*(\d+)$/$1$2/) {     # test if number
	substr($_,$[,0) = '+' unless $1; # Add missing sign
	s/^-0/+0/;
	$_;
    } else {
	'NaN';
    }
}

# Convert a number from string format to internal base 100000 format.
#   Assumes normalized value as input.
sub internal { #(num_str) return int_num_array
    local($d) = @_;
    ($is,$il) = (substr($d,$[,1),length($d)-2);
    substr($d,$[,1) = '';
    ($is, reverse(unpack("a" . ($il%5+1) . ("a5" x ($il/5)), $d)));
}

# Convert a number from internal base 100000 format to string format.
#   This routine scribbles all over input array.
sub external { #(int_num_array) return num_str
    $es = shift;
    grep($_ > 9999 || ($_ = substr('0000'.$_,-5)), @_);   # zero pad
    &'bnorm(join('', $es, reverse(@_)));    # reverse concat and normalize
}

# Negate input value.
sub main'bneg { #(num_str) return num_str
    local($_) = &'bnorm(@_);
    vec($_,0,8) ^= ord('+') ^ ord('-') unless $_ eq '+0';
    s/^./N/ unless /^[-+]/; # works both in ASCII and EBCDIC
    $_;
}

# Returns the absolute value of the input.
sub main'babs { #(num_str) return num_str
    &abs(&'bnorm(@_));
}

sub abs { # post-normalized abs for internal use
    local($_) = @_;
    s/^-/+/;
    $_;
}
\f
# Compares 2 values.  Returns one of undef, <0, =0, >0. (suitable for sort)
sub main'bcmp { #(num_str, num_str) return cond_code
    local($x,$y) = (&'bnorm($_[$[]),&'bnorm($_[$[+1]));
    if ($x eq 'NaN') {
	undef;
    } elsif ($y eq 'NaN') {
	undef;
    } else {
	&cmp($x,$y);
    }
}

sub cmp { # post-normalized compare for internal use
    local($cx, $cy) = @_;
    return 0 if ($cx eq $cy);

    local($sx, $sy) = (substr($cx, 0, 1), substr($cy, 0, 1));
    local($ld);

    if ($sx eq '+') {
      return  1 if ($sy eq '-' || $cy eq '+0');
      $ld = length($cx) - length($cy);
      return $ld if ($ld);
      return $cx cmp $cy;
    } else { # $sx eq '-'
      return -1 if ($sy eq '+');
      $ld = length($cy) - length($cx);
      return $ld if ($ld);
      return $cy cmp $cx;
    }

}

sub main'badd { #(num_str, num_str) return num_str
    local(*x, *y); ($x, $y) = (&'bnorm($_[$[]),&'bnorm($_[$[+1]));
    if ($x eq 'NaN') {
	'NaN';
    } elsif ($y eq 'NaN') {
	'NaN';
    } else {
	@x = &internal($x);             # convert to internal form
	@y = &internal($y);
	local($sx, $sy) = (shift @x, shift @y); # get signs
	if ($sx eq $sy) {
	    &external($sx, &add(*x, *y)); # if same sign add
	} else {
	    ($x, $y) = (&abs($x),&abs($y)); # make abs
	    if (&cmp($y,$x) > 0) {
		&external($sy, &sub(*y, *x));
	    } else {
		&external($sx, &sub(*x, *y));
	    }
	}
    }
}

sub main'bsub { #(num_str, num_str) return num_str
    &'badd($_[$[],&'bneg($_[$[+1]));    
}

# GCD -- Euclids algorithm Knuth Vol 2 pg 296
sub main'bgcd { #(num_str, num_str) return num_str
    local($x,$y) = (&'bnorm($_[$[]),&'bnorm($_[$[+1]));
    if ($x eq 'NaN' || $y eq 'NaN') {
	'NaN';
    } else {
	($x, $y) = ($y,&'bmod($x,$y)) while $y ne '+0';
	$x;
    }
}
\f
# routine to add two base 1e5 numbers
#   stolen from Knuth Vol 2 Algorithm A pg 231
#   there are separate routines to add and sub as per Kunth pg 233
sub add { #(int_num_array, int_num_array) return int_num_array
    local(*x, *y) = @_;
    $car = 0;
    for $x (@x) {
	last unless @y || $car;
	$x -= 1e5 if $car = (($x += shift(@y) + $car) >= 1e5) ? 1 : 0;
    }
    for $y (@y) {
	last unless $car;
	$y -= 1e5 if $car = (($y += $car) >= 1e5) ? 1 : 0;
    }
    (@x, @y, $car);
}

# subtract base 1e5 numbers -- stolen from Knuth Vol 2 pg 232, $x > $y
sub sub { #(int_num_array, int_num_array) return int_num_array
    local(*sx, *sy) = @_;
    $bar = 0;
    for $sx (@sx) {
	last unless @y || $bar;
	$sx += 1e5 if $bar = (($sx -= shift(@sy) + $bar) < 0);
    }
    @sx;
}

# multiply two numbers -- stolen from Knuth Vol 2 pg 233
sub main'bmul { #(num_str, num_str) return num_str
    local(*x, *y); ($x, $y) = (&'bnorm($_[$[]), &'bnorm($_[$[+1]));
    if ($x eq 'NaN') {
	'NaN';
    } elsif ($y eq 'NaN') {
	'NaN';
    } else {
	@x = &internal($x);
	@y = &internal($y);
	local($signr) = (shift @x ne shift @y) ? '-' : '+';
	@prod = ();
	for $x (@x) {
	    ($car, $cty) = (0, $[);
	    for $y (@y) {
		$prod = $x * $y + $prod[$cty] + $car;
		$prod[$cty++] =
		    $prod - ($car = int($prod * 1e-5)) * 1e5;
	    }
	    $prod[$cty] += $car if $car;
	    $x = shift @prod;
	}
	&external($signr, @x, @prod);
    }
}

# modulus
sub main'bmod { #(num_str, num_str) return num_str
    (&'bdiv(@_))[$[+1];
}
\f
sub main'bdiv { #(dividend: num_str, divisor: num_str) return num_str
    local (*x, *y); ($x, $y) = (&'bnorm($_[$[]), &'bnorm($_[$[+1]));
    return wantarray ? ('NaN','NaN') : 'NaN'
	if ($x eq 'NaN' || $y eq 'NaN' || $y eq '+0');
    return wantarray ? ('+0',$x) : '+0' if (&cmp(&abs($x),&abs($y)) < 0);
    @x = &internal($x); @y = &internal($y);
    $srem = $y[$[];
    $sr = (shift @x ne shift @y) ? '-' : '+';
    $car = $bar = $prd = 0;
    if (($dd = int(1e5/($y[$#y]+1))) != 1) {
	for $x (@x) {
	    $x = $x * $dd + $car;
	    $x -= ($car = int($x * 1e-5)) * 1e5;
	}
	push(@x, $car); $car = 0;
	for $y (@y) {
	    $y = $y * $dd + $car;
	    $y -= ($car = int($y * 1e-5)) * 1e5;
	}
    }
    else {
	push(@x, 0);
    }
    @q = (); ($v2,$v1) = @y[-2,-1];
    while ($#x > $#y) {
	($u2,$u1,$u0) = @x[-3..-1];
	$q = (($u0 == $v1) ? 99999 : int(($u0*1e5+$u1)/$v1));
	--$q while ($v2*$q > ($u0*1e5+$u1-$q*$v1)*1e5+$u2);
	if ($q) {
	    ($car, $bar) = (0,0);
	    for ($y = $[, $x = $#x-$#y+$[-1; $y <= $#y; ++$y,++$x) {
		$prd = $q * $y[$y] + $car;
		$prd -= ($car = int($prd * 1e-5)) * 1e5;
		$x[$x] += 1e5 if ($bar = (($x[$x] -= $prd + $bar) < 0));
	    }
	    if ($x[$#x] < $car + $bar) {
		$car = 0; --$q;
		for ($y = $[, $x = $#x-$#y+$[-1; $y <= $#y; ++$y,++$x) {
		    $x[$x] -= 1e5
			if ($car = (($x[$x] += $y[$y] + $car) > 1e5));
		}
	    }   
	}
	pop(@x); unshift(@q, $q);
    }
    if (wantarray) {
	@d = ();
	if ($dd != 1) {
	    $car = 0;
	    for $x (reverse @x) {
		$prd = $car * 1e5 + $x;
		$car = $prd - ($tmp = int($prd / $dd)) * $dd;
		unshift(@d, $tmp);
	    }
	}
	else {
	    @d = @x;
	}
	(&external($sr, @q), &external($srem, @d, $zero));
    } else {
	&external($sr, @q);
    }
}
1;
Commit	Line	Data
5303340c	1	package bigint;
a6d71656 GS	2	#
	3	# This library is no longer being maintained, and is included for backward
	4	# compatibility with Perl 4 programs which may require it.
	5	#
	6	# In particular, this should not be used as an example of modern Perl
	7	# programming techniques.
	8	#
	9	# Suggested alternative: Math::BigInt
	10	#
5303340c LW	11	# arbitrary size integer math package
	12	#
	13	# by Mark Biggar
	14	#
	15	# Canonical Big integer value are strings of the form
	16	# /^[+-]\d+$/ with leading zeros suppressed
	17	# Input values to these routines may be strings of the form
	18	# /^\s*[+-]?[\d\s]+$/.
	19	# Examples:
	20	# '+0' canonical zero value
	21	# ' -123 123 123' canonical value '-123123123'
	22	# '1 23 456 7890' canonical value '+1234567890'
	23	# Output values always always in canonical form
	24	#
	25	# Actual math is done in an internal format consisting of an array
	26	# whose first element is the sign (/^[+-]$/) and whose remaining
	27	# elements are base 100000 digits with the least significant digit first.
	28	# The string 'NaN' is used to represent the result when input arguments
	29	# are not numbers, as well as the result of dividing by zero
	30	#
	31	# routines provided are:
	32	#
	33	# bneg(BINT) return BINT negation
	34	# babs(BINT) return BINT absolute value
	35	# bcmp(BINT,BINT) return CODE compare numbers (undef,<0,=0,>0)
	36	# badd(BINT,BINT) return BINT addition
	37	# bsub(BINT,BINT) return BINT subtraction
	38	# bmul(BINT,BINT) return BINT multiplication
	39	# bdiv(BINT,BINT) return (BINT,BINT) division (quo,rem) just quo if scalar
	40	# bmod(BINT,BINT) return BINT modulus
	41	# bgcd(BINT,BINT) return BINT greatest common divisor
	42	# bnorm(BINT) return BINT normalization
	43	#
8990e307 LW	44
	45	$zero = 0;
	46
5303340c LW	47	\f
	48	# normalize string form of number. Strip leading zeros. Strip any
	49	# white space and add a sign, if missing.
	50	# Strings that are not numbers result the value 'NaN'.
8990e307	51
5303340c LW	52	sub main'bnorm { #(num_str) return num_str
	53	local($_) = @_;
	54	s/\s+//g; # strip white space
	55	if (s/^([+-]?)0*(\d+)$/$1$2/) { # test if number
79072805	56	substr($_,$[,0) = '+' unless $1; # Add missing sign
5303340c LW	57	s/^-0/+0/;
	58	$_;
	59	} else {
	60	'NaN';
	61	}
	62	}
	63
	64	# Convert a number from string format to internal base 100000 format.
	65	# Assumes normalized value as input.
	66	sub internal { #(num_str) return int_num_array
	67	local($d) = @_;
79072805 LW	68	($is,$il) = (substr($d,$[,1),length($d)-2);
79072805 LW	69	substr($d,$[,1) = '';
5303340c LW	70	($is, reverse(unpack("a" . ($il%5+1) . ("a5" x ($il/5)), $d)));
	71	}
	72
	73	# Convert a number from internal base 100000 format to string format.
	74	# This routine scribbles all over input array.
	75	sub external { #(int_num_array) return num_str
	76	$es = shift;
	77	grep($_ > 9999 \|\| ($_ = substr('0000'.$_,-5)), @_); # zero pad
	78	&'bnorm(join('', $es, reverse(@_))); # reverse concat and normalize
	79	}
	80
	81	# Negate input value.
	82	sub main'bneg { #(num_str) return num_str
	83	local($_) = &'bnorm(@_);
	84	vec($_,0,8) ^= ord('+') ^ ord('-') unless $_ eq '+0';
9d116dd7	85	s/^./N/ unless /^[-+]/; # works both in ASCII and EBCDIC
5303340c LW	86	$_;
	87	}
	88
	89	# Returns the absolute value of the input.
	90	sub main'babs { #(num_str) return num_str
	91	&abs(&'bnorm(@_));
	92	}
	93
	94	sub abs { # post-normalized abs for internal use
	95	local($_) = @_;
	96	s/^-/+/;
	97	$_;
	98	}
	99	\f
	100	# Compares 2 values. Returns one of undef, <0, =0, >0. (suitable for sort)
	101	sub main'bcmp { #(num_str, num_str) return cond_code
79072805	102	local($x,$y) = (&'bnorm($_[$[]),&'bnorm($_[$[+1]));
5303340c LW	103	if ($x eq 'NaN') {
	104	undef;
	105	} elsif ($y eq 'NaN') {
	106	undef;
	107	} else {
	108	&cmp($x,$y);
	109	}
	110	}
	111
	112	sub cmp { # post-normalized compare for internal use
	113	local($cx, $cy) = @_;
1e2e1ae8 JH	114	return 0 if ($cx eq $cy);
	115
	116	local($sx, $sy) = (substr($cx, 0, 1), substr($cy, 0, 1));
	117	local($ld);
	118
	119	if ($sx eq '+') {
	120	return 1 if ($sy eq '-' \|\| $cy eq '+0');
	121	$ld = length($cx) - length($cy);
	122	return $ld if ($ld);
	123	return $cx cmp $cy;
	124	} else { # $sx eq '-'
	125	return -1 if ($sy eq '+');
	126	$ld = length($cy) - length($cx);
	127	return $ld if ($ld);
	128	return $cy cmp $cx;
	129	}
	130
5303340c LW	131	}
	132
	133	sub main'badd { #(num_str, num_str) return num_str
79072805	134	local(x, y); ($x, $y) = (&'bnorm($_[$[]),&'bnorm($_[$[+1]));
5303340c LW	135	if ($x eq 'NaN') {
	136	'NaN';
	137	} elsif ($y eq 'NaN') {
	138	'NaN';
	139	} else {
	140	@x = &internal($x); # convert to internal form
	141	@y = &internal($y);
	142	local($sx, $sy) = (shift @x, shift @y); # get signs
	143	if ($sx eq $sy) {
	144	&external($sx, &add(x, y)); # if same sign add
	145	} else {
	146	($x, $y) = (&abs($x),&abs($y)); # make abs
	147	if (&cmp($y,$x) > 0) {
	148	&external($sy, &sub(y, x));
	149	} else {
	150	&external($sx, &sub(x, y));
	151	}
	152	}
	153	}
	154	}
	155
	156	sub main'bsub { #(num_str, num_str) return num_str
79072805	157	&'badd($_[$[],&'bneg($_[$[+1]));
5303340c LW	158	}
	159
	160	# GCD -- Euclids algorithm Knuth Vol 2 pg 296
	161	sub main'bgcd { #(num_str, num_str) return num_str
79072805	162	local($x,$y) = (&'bnorm($_[$[]),&'bnorm($_[$[+1]));
68decaef	163	if ($x eq 'NaN' \|\| $y eq 'NaN') {
5303340c	164	'NaN';
68decaef	165	} else {
5303340c LW	166	($x, $y) = ($y,&'bmod($x,$y)) while $y ne '+0';
	167	$x;
	168	}
	169	}
	170	\f
68decaef	171	# routine to add two base 1e5 numbers
5303340c LW	172	# stolen from Knuth Vol 2 Algorithm A pg 231
	173	# there are separate routines to add and sub as per Kunth pg 233
	174	sub add { #(int_num_array, int_num_array) return int_num_array
	175	local(x, y) = @_;
	176	$car = 0;
	177	for $x (@x) {
	178	last unless @y \|\| $car;
55497cff	179	$x -= 1e5 if $car = (($x += shift(@y) + $car) >= 1e5) ? 1 : 0;
5303340c LW	180	}
	181	for $y (@y) {
	182	last unless $car;
55497cff	183	$y -= 1e5 if $car = (($y += $car) >= 1e5) ? 1 : 0;
5303340c LW	184	}
	185	(@x, @y, $car);
	186	}
	187
68decaef	188	# subtract base 1e5 numbers -- stolen from Knuth Vol 2 pg 232, $x > $y
5303340c LW	189	sub sub { #(int_num_array, int_num_array) return int_num_array
	190	local(sx, sy) = @_;
	191	$bar = 0;
	192	for $sx (@sx) {
	193	last unless @y \|\| $bar;
e334a159	194	$sx += 1e5 if $bar = (($sx -= shift(@sy) + $bar) < 0);
5303340c LW	195	}
	196	@sx;
	197	}
	198
	199	# multiply two numbers -- stolen from Knuth Vol 2 pg 233
	200	sub main'bmul { #(num_str, num_str) return num_str
79072805	201	local(x, y); ($x, $y) = (&'bnorm($_[$[]), &'bnorm($_[$[+1]));
5303340c LW	202	if ($x eq 'NaN') {
	203	'NaN';
	204	} elsif ($y eq 'NaN') {
	205	'NaN';
	206	} else {
	207	@x = &internal($x);
	208	@y = &internal($y);
	209	local($signr) = (shift @x ne shift @y) ? '-' : '+';
	210	@prod = ();
	211	for $x (@x) {
79072805	212	($car, $cty) = (0, $[);
5303340c LW	213	for $y (@y) {
	214	$prod = $x * $y + $prod[$cty] + $car;
	215	$prod[$cty++] =
68decaef	216	$prod - ($car = int($prod * 1e-5)) * 1e5;
5303340c LW	217	}
	218	$prod[$cty] += $car if $car;
	219	$x = shift @prod;
	220	}
	221	&external($signr, @x, @prod);
	222	}
	223	}
	224
	225	# modulus
	226	sub main'bmod { #(num_str, num_str) return num_str
79072805	227	(&'bdiv(@_))[$[+1];
5303340c LW	228	}
	229	\f
	230	sub main'bdiv { #(dividend: num_str, divisor: num_str) return num_str
79072805	231	local (x, y); ($x, $y) = (&'bnorm($_[$[]), &'bnorm($_[$[+1]));
5303340c LW	232	return wantarray ? ('NaN','NaN') : 'NaN'
	233	if ($x eq 'NaN' \|\| $y eq 'NaN' \|\| $y eq '+0');
	234	return wantarray ? ('+0',$x) : '+0' if (&cmp(&abs($x),&abs($y)) < 0);
	235	@x = &internal($x); @y = &internal($y);
79072805	236	$srem = $y[$[];
5303340c LW	237	$sr = (shift @x ne shift @y) ? '-' : '+';
5303340c LW	238	$car = $bar = $prd = 0;
68decaef	239	if (($dd = int(1e5/($y[$#y]+1))) != 1) {
5303340c LW	240	for $x (@x) {
5303340c LW	241	$x = $x * $dd + $car;
68decaef	242	$x -= ($car = int($x * 1e-5)) * 1e5;
5303340c LW	243	}
	244	push(@x, $car); $car = 0;
	245	for $y (@y) {
	246	$y = $y * $dd + $car;
68decaef	247	$y -= ($car = int($y * 1e-5)) * 1e5;
5303340c LW	248	}
	249	}
	250	else {
	251	push(@x, 0);
	252	}
ed6116ce	253	@q = (); ($v2,$v1) = @y[-2,-1];
5303340c	254	while ($#x > $#y) {
ed6116ce	255	($u2,$u1,$u0) = @x[-3..-1];
68decaef LW	256	$q = (($u0 == $v1) ? 99999 : int(($u0*1e5+$u1)/$v1));
68decaef LW	257	--$q while ($v2$q > ($u01e5+$u1-$q$v1)1e5+$u2);
5303340c LW	258	if ($q) {
5303340c LW	259	($car, $bar) = (0,0);
79072805	260	for ($y = $[, $x = $#x-$#y+$[-1; $y <= $#y; ++$y,++$x) {
5303340c	261	$prd = $q * $y[$y] + $car;
68decaef LW	262	$prd -= ($car = int($prd * 1e-5)) * 1e5;
68decaef LW	263	$x[$x] += 1e5 if ($bar = (($x[$x] -= $prd + $bar) < 0));
5303340c LW	264	}
	265	if ($x[$#x] < $car + $bar) {
	266	$car = 0; --$q;
79072805	267	for ($y = $[, $x = $#x-$#y+$[-1; $y <= $#y; ++$y,++$x) {
68decaef LW	268	$x[$x] -= 1e5
68decaef LW	269	if ($car = (($x[$x] += $y[$y] + $car) > 1e5));
5303340c LW	270	}
	271	}
	272	}
	273	pop(@x); unshift(@q, $q);
	274	}
	275	if (wantarray) {
	276	@d = ();
	277	if ($dd != 1) {
	278	$car = 0;
	279	for $x (reverse @x) {
68decaef	280	$prd = $car * 1e5 + $x;
5303340c LW	281	$car = $prd - ($tmp = int($prd / $dd)) * $dd;
	282	unshift(@d, $tmp);
	283	}
	284	}
	285	else {
	286	@d = @x;
	287	}
8990e307	288	(&external($sr, @q), &external($srem, @d, $zero));
5303340c LW	289	} else {
	290	&external($sr, @q);
	291	}
	292	}
	293	1;