ref: b39057dffedac61fd6c028908a9aaadf4426b446
dir: /man/2/ipints/
.TH IPINTS 2
.SH NAME
ipints: IPint \- `infinite' precision integer utility functions
.SH SYNOPSIS
.EX
include "ipints.m"
ipints:= load IPints IPints->PATH;
IPint: adt
{
iptob64: fn(i: self ref IPint): string;
iptob64z: fn(i: self ref IPint): string;
b64toip: fn(str: string) : ref IPint;
iptobytes: fn(i: self ref IPint): array of byte;
bytestoip: fn(buf: array of byte): ref IPint;
iptobebytes: fn(i: self ref IPint): array of byte;
bebytestoip: fn(buf: array of byte): ref IPint;
inttoip: fn(i: int): ref IPint;
iptoint: fn(i: self ref IPint): int;
iptostr: fn(i: self ref IPint, base: int): string;
strtoip: fn(str: string, base: int): ref IPint;
random: fn(nbits: int): ref IPint;
copy: fn(i: self ref IPint): ref IPint;
bits: fn(i: self ref IPint): int;
expmod: fn(base: self ref IPint, exp, mod: ref IPint):ref IPint;
add: fn(i1: self ref IPint, i2: ref IPint): ref IPint;
sub: fn(i1: self ref IPint, i2: ref IPint): ref IPint;
neg: fn(i: self ref IPint): ref IPint;
mul: fn(i1: self ref IPint, i2: ref IPint): ref IPint;
div: fn(i1: self ref IPint, i2: ref IPint): (ref IPint, ref IPint);
mod: fn(i1: self ref IPint, i2: ref IPint): ref IPint;
eq: fn(i1: self ref IPint, i2: ref IPint): int;
cmp: fn(i1: self ref IPint, i2: ref IPint): int;
shl: fn(i: self ref IPint, n: int): ref IPint;
shr: fn(i: self ref IPint, n: int): ref IPint;
and: fn(i1: self ref IPint, i2: ref IPint): ref IPint;
ori: fn(i1: self ref IPint, i2: ref IPint): ref IPint;
not: fn(i: self ref IPint): ref IPint;
xor: fn(i1: self ref IPint, i2: ref IPint): ref IPint;
};
.EE
.SH DESCRIPTION
.B IPint
provides the following arbitrary-length integer manipulation functions required for cryptographic support in Limbo:
.TP
.IB i .iptob64()
Returns a string that represents a large integer textually in base 64 for convenient transmission over a network connection.
.TP
.IB i .iptob64z()
Returns a similar representation to
.B iptob64
but ensures that the top bit of the received value is zero.
.TP
.BI b64toip( str )
Returns the
.B IPint
represented by the base-64 encoded
.IR str .
.TP
.IB i .iptobytes()
Returns an array of bytes representing a large integer. The representation includes both positive and negative numbers.
.TP
.BI bytestoip( buf )
The inverse operation of
.BR iptobytes .
.TP
.IB i .iptobebytes()
Returns an array of bytes in big-endian format representing the magnitude of a large integer; used for instance to pass a value to
.IR ssl (3).
Only non-negative numbers are represented.
.TP
.BI bebytestoip( buf )
The inverse operation of
.BR iptobebytes .
.TP
.BI inttoip( i )
Creates a new large integer from integer
.IR i .
.TP
.IB i .iptoint()
Converts a large integer
.I i
to an
.BR int ;
returns 0 on error.
.TP
.IB i .iptostr( base )
Converts a large integer to a string in base
.IR base ;
returns nil on error.
Only the bases 10, 16, 32, and 64 are
supported. Anything else defaults to 16.
.TP
.BI strtoip( str , base )
Converts a string
.I str
representing a number in in base
.I base
to a large integer; returns nil on error.
Only the bases 10, 16, 32, and 64 are
supported.
.TP
.BI random( nbits )
Returns a large random number of length at most
.IR minbits .
The largest number allowed in the current implementation is
2^8192-1 .
The seed for the generator is obtained by duelling clocks.
.TP
.IB i .copy()
Returns a reference to the same value as
.IR i .
.TP
.IB i .bits()
Returns the number of bits of precision of
.IR i .
.TP
.IB base .expmod( "exp , mod" )
Returns
.BI ( base ** exp ") mod " mod.
.TP
.IB i1 .add( i2 )
Returns
.RI ( i1 + i2 ).
.TP
.IB i1 .sub( i2 )
Returns
.RI ( i1 - i2 ).
.TP
.IB i1 .mul ( i2 )
Returns
.IR i1*i2 .
.TP
.IB i1 .div ( i2 )
Returns
.RI ( i1 / i2,
.IR i1 rem i2 ).
.TP
.IB i1 .mod ( i2 )
Returns
.RI ( i1 mod i2 ).
.TP
.IB i1 .eq( i2 )
Returns 1 if
.I i1
and
.I i2
are equal; 0 otherwise.
.TP
.IB i1 .cmp( i2 )
Compares two large integers, returning 1 if
.I i1
is larger,
-1 if
.I i2
is larger, and 0 if they are equal.
.TP
.IB i .shl( n )
Returns
.IR i << n
.TP
.IB i .shr( n )
Returns
.IR i >> n
.TP
.IB i1 .and( i2 )
Returns
.IR i & n ,
bitwise AND
.TP
.IB i1 .ori( i2 )
Returns
.IR i | n ,
bitwise inclusive-OR
(it is
.B ori
because plain
.B or
is a Limbo keyword)
.TP
.IB i .not()
Returns
.RI ~ i ,
bitwise ones-complement
.TP
.IB i1 .xor( i2 )
Returns
.IR i ^ n ,
bitwise exclusive-OR
.SH SOURCE
.B /libinterp/ipint.c
.br
.B /libmp