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c5a4355407
First versioned release to celebrate the increased capabilities of `nimble` to work with versions ;) This release is "nearly" feature-complete but still has some open API/ABI questions, in particular around endians, bitops and other convenience features. Ideally, a 1.0 release would also not carry a stew dependency but rather see that part of stew exported to its own [intops](https://github.com/status-im/nim-stew/pull/187) library that would gather all the low-level stuff and define a common minimally supported API for all kinds of integers, native or not.
Stint (Stack-based arbitrary precision integers)
stint provides efficient and convenient N-bit integers for Nim, for arbitrary
sizes of N decided at compile time with an interface similar to to
int64/uint64.
In addition to basic integer operations, stint also contains primtives for
modular arithmetic, endian conversion, basic I/O, bit twiddling etc.
stint integers, like their intXX/uintXX counterpart in Nim are stack-based
values, meaning that they are naturally allocation-free and have value-based
semantics.
import stint
func addmul(a, b, c: UInt256): UInt256 =
a * b + c
echo addmul(u256"100000000000000000000000000000", u256"1", u256"2")
Priorities
- Portability
- 32 and 64 bit
- ARM/x86/x86_64 extensively tested
- Additionally RISC-V and MIPS for open hardware and low power IoT devices.
- Speed, library is carefully tuned to produce the best assembly given the current compilers. However, the library itself does not require assembly for portability.
- No heap/dynamic allocation
- Ease of use:
- Use traditional
+,-,+=, etc operators like on native types - converting to and from raw byte BigInts (also called octet string in IETF specs)
- converting to and from Hex
- converting to and from decimal strings
- Use traditional
Non-priorities include:
- constant-time operation (not suitable for certain kinds of cryptography out of the box)
- runtime precision
See also
- constantine - modular arithmetic and elliptic curve operations focusing on cryptography and constant-time implementation
- N2472 -
_ExtInt(N)- native arbitrary precision integers for C - stew - helpers and utilities for ordinary Nim integers (
endians2,bitops2etc)
License
Licensed and distributed under either of
- MIT license: LICENSE-MIT or http://opensource.org/licenses/MIT
or
- Apache License, Version 2.0, (LICENSE-APACHEv2 or http://www.apache.org/licenses/LICENSE-2.0)
at your option. This file may not be copied, modified, or distributed except according to those terms.