1 files changed, 344 insertions, 0 deletions
diff --git a/v_windows/v/vlib/math/big/big.c.v b/v_windows/v/vlib/math/big/big.c.v
new file mode 100644
index 0000000..7ef0534
--- /dev/null
+++ b/v_windows/v/vlib/math/big/big.c.v
@@ -0,0 +1,344 @@
+module big
+
+// Wrapper for https://github.com/kokke/tiny-bignum-c
+#flag -I @VEXEROOT/thirdparty/bignum
+#flag @VEXEROOT/thirdparty/bignum/bn.o
+#include "bn.h"
+
+struct C.bn {
+mut:
+	array [32]u32
+}
+
+// Big unsigned integer number.
+type Number = C.bn
+
+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 &char, nbytes int)
+
+fn C.bignum_to_string(n &Number, s &char, maxsize int)
+
+// c = a + b
+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 d=a%b
+fn C.bignum_divmod(a &Number, b &Number, c &Number, d &Number)
+
+// c = 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 xor b
+fn C.bignum_xor(a &Number, b &Number, c &Number)
+
+// b = a << nbits
+fn C.bignum_lshift(a &Number, b &Number, nbits int)
+
+// b = a >> nbits
+fn C.bignum_rshift(a &Number, b &Number, nbits int)
+
+fn C.bignum_cmp(a &Number, b &Number) int
+
+fn C.bignum_is_zero(a &Number) int
+
+// n++
+fn C.bignum_inc(n &Number)
+
+// n--
+fn C.bignum_dec(n &Number)
+
+// c = a ^ b
+fn C.bignum_pow(a &Number, b &Number, c &Number)
+
+// b = integer_square_root_of(a)
+fn C.bignum_isqrt(a &Number, b &Number)
+
+// copy src number to dst number
+fn C.bignum_assign(dst &Number, src &Number)
+
+// new returns a bignum, initialized to 0
+pub fn new() Number {
+	return Number{}
+}
+
+// conversion actions to/from big numbers:
+// from_int converts an ordinary int number `i` to big.Number
+pub fn from_int(i int) Number {
+	n := Number{}
+	C.bignum_from_int(&n, i)
+	return n
+}
+
+// from_u64 converts an ordinary u64 number `u` to big.Number
+pub fn from_u64(u u64) Number {
+	n := Number{}
+	C.bignum_from_int(&n, u)
+	return n
+}
+
+// from_hex_string converts a hex string to big.Number
+pub fn from_hex_string(input string) Number {
+	mut s := input.trim_prefix('0x')
+	if s.len == 0 {
+		s = '0'
+	}
+	padding := '0'.repeat((8 - s.len % 8) % 8)
+	s = padding + s
+	n := Number{}
+	C.bignum_from_string(&n, &char(s.str), s.len)
+	return n
+}
+
+// from_string converts a decimal string to big.Number
+pub fn from_string(input string) Number {
+	mut n := from_int(0)
+	for _, c in input {
+		d := from_int(int(c - `0`))
+		n = (n * big.ten) + d
+	}
+	return n
+}
+
+// from_bytes converts an array of bytes (little-endian) to a big.Number.
+// Higher precedence bytes are expected at lower indices in the array.
+pub fn from_bytes(input []byte) ?Number {
+	if input.len > 128 {
+		return error('input array too large. big.Number can only hold up to 1024 bit numbers')
+	}
+	// pad input
+	mut padded_input := []byte{len: ((input.len + 3) & ~0x3) - input.len, cap: (input.len + 3) & ~0x3, init: 0x0}
+	padded_input << input
+	// combine every 4 bytes into a u32 and insert into n.array
+	mut n := Number{}
+	for i := 0; i < padded_input.len; i += 4 {
+		x3 := u32(padded_input[i])
+		x2 := u32(padded_input[i + 1])
+		x1 := u32(padded_input[i + 2])
+		x0 := u32(padded_input[i + 3])
+		val := (x3 << 24) | (x2 << 16) | (x1 << 8) | x0
+		n.array[(padded_input.len - i) / 4 - 1] = val
+	}
+	return n
+}
+
+// .int() converts (a small) big.Number `n` to an ordinary integer.
+pub fn (n &Number) int() int {
+	r := C.bignum_to_int(n)
+	return r
+}
+
+const (
+	ten = from_int(10)
+)
+
+// .str returns a decimal representation of the big unsigned integer number n.
+pub fn (n &Number) str() string {
+	if n.is_zero() {
+		return '0'
+	}
+	mut digits := []byte{}
+	mut x := n.clone()
+
+	for !x.is_zero() {
+		// changes to reflect new api
+		div, mod := divmod(&x, &big.ten)
+		digits << byte(mod.int()) + `0`
+		x = div
+	}
+	return digits.reverse().bytestr()
+}
+
+// .hexstr returns a hexadecimal representation of the bignum `n`
+pub fn (n &Number) hexstr() string {
+	mut buf := [8192]byte{}
+	mut s := ''
+	unsafe {
+		bp := &buf[0]
+		// NB: C.bignum_to_string(), returns the HEXADECIMAL representation of the bignum n
+		C.bignum_to_string(n, &char(bp), 8192)
+		s = tos_clone(bp)
+	}
+	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
+}
+
+// divmod returns a pair of quotient and remainder from div modulo operation
+// between two bignums `a` and `b`
+pub fn divmod(a &Number, b &Number) (Number, Number) {
+	c := Number{}
+	d := Number{}
+	C.bignum_divmod(a, b, &c, &d)
+	return c, d
+}
+
+// //////////////////////////////////////////////////////////
+pub fn cmp(a &Number, b &Number) int {
+	return C.bignum_cmp(a, b)
+}
+
+pub fn (a &Number) is_zero() bool {
+	return C.bignum_is_zero(a) != 0
+}
+
+pub fn (mut a Number) inc() {
+	C.bignum_inc(&a)
+}
+
+pub fn (mut a 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(from_int(n))
+}
+
+// bytes returns an array of the bytes for the number `n`,
+// in little endian format, where .bytes()[0] is the least
+// significant byte. The result is NOT trimmed, and will contain 0s, even
+// after the significant bytes.
+// This method is faster than .bytes_trimmed(), but may be less convenient.
+// Example: assert big.from_int(1).bytes()[0] == byte(0x01)
+// Example: assert big.from_int(1024).bytes()[1] == byte(0x04)
+// Example: assert big.from_int(1048576).bytes()[2] == byte(0x10)
+pub fn (n &Number) bytes() []byte {
+	mut res := []byte{len: 128, init: 0}
+	unsafe { C.memcpy(res.data, n, 128) }
+	return res
+}
+
+// bytes_trimmed returns an array of the bytes for the number `n`,
+// in little endian format, where .bytes_trimmed()[0] is the least
+// significant byte. The result is trimmed, so that *the last* byte
+// of the result is also the the last meaningfull byte, != 0 .
+// Example: assert big.from_int(1).bytes_trimmed() == [byte(0x01)]
+// Example: assert big.from_int(1024).bytes_trimmed() == [byte(0x00), 0x04]
+// Example: assert big.from_int(1048576).bytes_trimmed() == [byte(0x00), 0x00, 0x10]
+pub fn (n &Number) bytes_trimmed() []byte {
+	mut res := []byte{len: 128, init: 0}
+	unsafe { C.memcpy(res.data, n, 128) }
+	mut non_zero_idx := 127
+	for ; non_zero_idx >= 0; non_zero_idx-- {
+		if res[non_zero_idx] != 0 {
+			break
+		}
+	}
+	res.trim(non_zero_idx + 1)
+	return res
+}