module bignum // Wrapper for https://github.com/kokke/tiny-bignum-c #flag -I @VROOT/thirdparty/bignum #flag @VROOT/thirdparty/bignum/bn.o #include "bn.h" const ( STRING_BUFFER_SIZE = 8192 ) pub struct Number { array [32]u32 } fn C.bignum_init( n &Number ) fn C.bignum_from_int( n &Number, i u64 ) fn C.bignum_to_int( n &Number ) int fn C.bignum_from_string( n &Number, s byteptr, nbytes int) fn C.bignum_to_string( n &Number, s byteptr, maxsize int) fn C.bignum_add( a &Number, b &Number, c &Number) // c = a + b fn C.bignum_sub( a &Number, b &Number, c &Number) // c = a - b fn C.bignum_mul( a &Number, b &Number, c &Number) // c = a * b fn C.bignum_div( a &Number, b &Number, c &Number) // c = a / b fn C.bignum_mod( a &Number, b &Number, c &Number) // c = a % b fn C.bignum_divmod( a &Number, b &Number, c &Number, d &Number) // c = a/b d=a%b fn C.bignum_and( a &Number, b &Number, c &Number) // c = a & b fn C.bignum_or( a &Number, b &Number, c &Number) // c = a | b fn C.bignum_xor( a &Number, b &Number, c &Number) // c = a xor b fn C.bignum_lshift( a &Number, b &Number, nbits int) // b = a << nbits fn C.bignum_rshift( a &Number, b &Number, nbits int) // b = a >> nbits fn C.bignum_cmp( a &Number, b &Number) int fn C.bignum_is_zero( a &Number) int fn C.bignum_inc(n &Number) fn C.bignum_dec(n &Number) fn C.bignum_pow( a &Number, b &Number, c &Number) // c = a ^ b fn C.bignum_isqrt( a &Number, b &Number) // b = integer_square_root_of(a) fn C.bignum_assign( dst &Number, src &Number) // copy src number to dst number //////////////////////////////////////////////////////////// // conversion actions to/from big numbers: pub fn new_bignum() Number { return Number{} } pub fn from_int(i int) Number { n := Number{} C.bignum_from_int( &n, i) return n } pub fn from_u64(u u64) Number { n := Number{} C.bignum_from_int( &n, u) return n } pub fn from_string(s string) Number { n := Number{} C.bignum_from_string(&n, s.str, s.len) return n } pub fn (n Number) int() int { r := C.bignum_to_int(&n) return r } pub fn (n Number) str() string { // TODO: return a decimal representation of the bignumber n. // A decimal representation will be easier to use in the repl // but will be slower to calculate. Also, it is not implemented // in the bn library. return 'Number (in hex): ' + n.hexstr() } pub fn (n Number) hexstr() string { mut buf := [STRING_BUFFER_SIZE]byte C.bignum_to_string( &n, buf, STRING_BUFFER_SIZE) // NB: bignum_to_string , returns the HEXADECIMAL representation of the bignum n s := tos_clone( buf ) if s.len == 0 { return '0' } return s } //////////////////////////////////////////////////////////// // overloaded ops for the numbers: pub fn (a Number) + (b Number) Number { c := Number{} C.bignum_add(&a, &b, &c) return c } pub fn (a Number) - (b Number) Number { c := Number{} C.bignum_sub(&a, &b, &c) return c } pub fn (a Number) * (b Number) Number { c := Number{} C.bignum_mul(&a, &b, &c) return c } pub fn (a Number) / (b Number) Number { c := Number{} C.bignum_div(&a, &b, &c) return c } pub fn (a Number) % (b Number) Number { c := Number{} C.bignum_mod(&a, &b, &c) return c } pub fn divmod( a &Number, b &Number, c &Number) Number { d := Number{} C.bignum_divmod( a, b, c, &d) return d } //////////////////////////////////////////////////////////// pub fn cmp(a Number, b Number) int { return C.bignum_cmp(&a,&b) } pub fn (a Number) is_zero() bool { return int(C.bignum_is_zero(&a)) != 0 } pub fn (a mut Number) inc() { C.bignum_inc(a) } pub fn (a mut Number) dec() { C.bignum_dec(a) } pub fn pow(a Number, b Number) Number { c := Number{} C.bignum_pow(&a,&b,&c) return c } pub fn (a Number) isqrt() Number { b := Number{} C.bignum_isqrt(&a,&b) return b } //////////////////////////////////////////////////////////// pub fn b_and(a Number, b Number) Number { c := Number{} C.bignum_and(&a,&b,&c) return c } pub fn b_or(a Number, b Number) Number { c := Number{} C.bignum_or(&a,&b,&c) return c } pub fn b_xor(a Number, b Number) Number { c := Number{} C.bignum_xor(&a,&b,&c) return c } pub fn (a Number) lshift(nbits int) Number { b := Number{} C.bignum_lshift(&a,&b,nbits) return b } pub fn (a Number) rshift(nbits int) Number { b := Number{} C.bignum_rshift(&a,&b,nbits) return b } pub fn (a Number) clone() Number { b := Number{} C.bignum_assign(&b,&a) return b } //////////////////////////////////////////////////////////// pub fn factorial(nn Number) Number { mut n := nn.clone() mut a := nn.clone() n.dec() mut i:=1 for !n.is_zero() { res := a * n n.dec() a = res i++ } return a } pub fn fact(n int) Number { return factorial( bignum.from_int(n) ) }