Cairo vector

.cairo

# @title The beginnings of Vector in Cairo
# @author 0xNonCents
# @notice Please let me know if this will save on gas compared to a @storage array
# MIT License

%builtins pedersen range_check

from starkware.cairo.common.alloc import alloc
from starkware.cairo.common.hash import hash2
from starkware.cairo.common.cairo_builtins import HashBuiltin
from starkware.cairo.common.math import unsigned_div_rem, split_felt, assert_nn, assert_le
from starkware.cairo.common.registers import get_fp_and_pc

# @member s the starting pointer of the vector
# @member e the ending pointer of the vector
# @member size the current size of the vector
struct vector:
    member s : felt*
    member e : felt*
    member size : felt
end

# @notice Appends {value} to the (e)nd of a vector. Increment the end pointer and size by 1 (SIZE of felt)
# @param v The vector which recieves the new element
# @param value The element that is added to the end of the vector
# @return A new vector containing the added element
func push{pedersen_ptr : HashBuiltin*, range_check_ptr}(v : vector, value : felt) -> (res : vector):
    let end_ptr = v.e
    [end_ptr] = value
    let new_v : vector = vector(v.s, end_ptr + 1, v.size + 1)
    return (new_v)
end

# @notice Retrieves the element at a given {index}
# @dev Will break if index is out of vector bounds
# @param v The vector
# @param index The index at which to get the desired value
# @return The value of the vector at an index
func at{pedersen_ptr : HashBuiltin*, range_check_ptr}(v : vector, index : felt) -> (res : felt):
    let res = v.s[index]
    return (res)
end

# @notice the drive function to demonstrate the vector
# @dev To run: cairo-compile ./contracts/vector.cairo --output ./artifacts/vector.json && cairo-run --program=./artifacts/vector.json --layout=all

func main{pedersen_ptr : HashBuiltin*, range_check_ptr}():
    alloc_locals
    let s : felt* = alloc()
    let e : felt* = s + 1
    let v : vector = vector(s, e, 4)

    let (v_2 : vector) = push(v, 1)
    let (res : vector) = push(v_2, 3)

    let ptr = res.e
    let val = [res.e - 1]
    %{ print(ids.ptr) %}
    %{ print(ids.val) %}

    let (val_at) = at(v_2, 2)
    assert 3 = val_at
    %{ print(ids.val_at) %}

    let (val_at) = at(v_2, 1)
    assert 1 = val_at
    %{ print(ids.val_at) %}

    return ()
end

I'd like to use it in a project I'm working on. What license is it under? 🙏

Hi Milan. It is open source. Use it, improve it, sell it

MIT License

Copyright (c) 2022 0xNonCents

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

Cheers! If I get rich using this, beer's on me 🍻