snarkvm_console_program/data/literal/cast/
mod.rs

1// Copyright 2024 Aleo Network Foundation
2// This file is part of the snarkVM library.
3
4// Licensed under the Apache License, Version 2.0 (the "License");
5// you may not use this file except in compliance with the License.
6// You may obtain a copy of the License at:
7
8// http://www.apache.org/licenses/LICENSE-2.0
9
10// Unless required by applicable law or agreed to in writing, software
11// distributed under the License is distributed on an "AS IS" BASIS,
12// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13// See the License for the specific language governing permissions and
14// limitations under the License.
15
16mod boolean;
17mod field;
18mod integer;
19mod scalar;
20
21use crate::{Literal, LiteralType};
22use snarkvm_console_network::Network;
23use snarkvm_console_types::{Boolean, integers::Integer, prelude::*};
24
25/// Unary operator for casting values of one type to another.
26pub trait Cast<T: Sized = Self> {
27    /// Casts the value of `self` into a value of type `T`.
28    ///
29    /// This method checks that the cast does not lose any bits of information,
30    /// and returns an error if it does.
31    fn cast(&self) -> Result<T>;
32}
33
34impl<N: Network> Literal<N> {
35    /// Casts the literal to the given literal type.
36    ///
37    /// This method checks that the cast does not lose any bits of information,
38    /// and returns an error if it does.
39    ///
40    /// The hierarchy of casting is as follows:
41    ///  - (`Address`, `Group`) <-> `Field` <-> `Scalar` <-> `Integer` <-> `Boolean`
42    ///  - `Signature` (not supported)
43    ///  - `String` (not supported)
44    ///
45    /// Note that casting to left along the hierarchy always preserves information.
46    pub fn cast(&self, to_type: LiteralType) -> Result<Self> {
47        match self {
48            Self::Address(address) => cast_group_to_type(address.to_group(), to_type),
49            Self::Boolean(boolean) => cast_boolean_to_type(boolean, to_type),
50            Self::Field(field) => cast_field_to_type(field, to_type),
51            Self::Group(group) => cast_group_to_type(group, to_type),
52            Self::I8(integer) => cast_integer_to_type(integer, to_type),
53            Self::I16(integer) => cast_integer_to_type(integer, to_type),
54            Self::I32(integer) => cast_integer_to_type(integer, to_type),
55            Self::I64(integer) => cast_integer_to_type(integer, to_type),
56            Self::I128(integer) => cast_integer_to_type(integer, to_type),
57            Self::U8(integer) => cast_integer_to_type(integer, to_type),
58            Self::U16(integer) => cast_integer_to_type(integer, to_type),
59            Self::U32(integer) => cast_integer_to_type(integer, to_type),
60            Self::U64(integer) => cast_integer_to_type(integer, to_type),
61            Self::U128(integer) => cast_integer_to_type(integer, to_type),
62            Self::Scalar(scalar) => cast_scalar_to_type(scalar, to_type),
63            Self::Signature(..) => bail!("Cannot cast a signature literal to another type."),
64            Self::String(..) => bail!("Cannot cast a string literal to another type."),
65        }
66    }
67}
68
69/// A helper macro to implement the body of the `cast` methods.
70macro_rules! impl_cast_body {
71    ($type_name:ident, $cast:ident, $input:expr, $to_type:expr) => {
72        match $to_type {
73            LiteralType::Address => Ok(Literal::Address($input.$cast()?)),
74            LiteralType::Boolean => Ok(Literal::Boolean($input.$cast()?)),
75            LiteralType::Field => Ok(Literal::Field($input.$cast()?)),
76            LiteralType::Group => Ok(Literal::Group($input.$cast()?)),
77            LiteralType::I8 => Ok(Literal::I8($input.$cast()?)),
78            LiteralType::I16 => Ok(Literal::I16($input.$cast()?)),
79            LiteralType::I32 => Ok(Literal::I32($input.$cast()?)),
80            LiteralType::I64 => Ok(Literal::I64($input.$cast()?)),
81            LiteralType::I128 => Ok(Literal::I128($input.$cast()?)),
82            LiteralType::U8 => Ok(Literal::U8($input.$cast()?)),
83            LiteralType::U16 => Ok(Literal::U16($input.$cast()?)),
84            LiteralType::U32 => Ok(Literal::U32($input.$cast()?)),
85            LiteralType::U64 => Ok(Literal::U64($input.$cast()?)),
86            LiteralType::U128 => Ok(Literal::U128($input.$cast()?)),
87            LiteralType::Scalar => Ok(Literal::Scalar($input.$cast()?)),
88            LiteralType::Signature => {
89                bail!(concat!("Cannot cast a ", stringify!($type_name), " literal to a signature type."))
90            }
91            LiteralType::String => {
92                bail!(concat!("Cannot cast a ", stringify!($type_name), " literal to a string type."))
93            }
94        }
95    };
96}
97
98/// Casts a boolean literal to the given literal type.
99fn cast_boolean_to_type<N: Network>(input: &Boolean<N>, to_type: LiteralType) -> Result<Literal<N>> {
100    impl_cast_body!(boolean, cast, input, to_type)
101}
102
103/// Casts a field literal to the given literal type.
104fn cast_field_to_type<N: Network>(input: &Field<N>, to_type: LiteralType) -> Result<Literal<N>> {
105    impl_cast_body!(field, cast, input, to_type)
106}
107
108/// Casts a group literal to the given literal type.
109fn cast_group_to_type<N: Network>(input: &Group<N>, to_type: LiteralType) -> Result<Literal<N>> {
110    match to_type {
111        LiteralType::Address => Ok(Literal::Address(Address::new(*input))),
112        LiteralType::Group => Ok(Literal::Group(*input)),
113        _ => cast_field_to_type(&input.to_x_coordinate(), to_type),
114    }
115}
116
117/// Casts an integer literal to the given literal type.
118fn cast_integer_to_type<N: Network, I: IntegerType>(
119    input: &integers::Integer<N, I>,
120    to_type: LiteralType,
121) -> Result<Literal<N>>
122where
123    i8: TryFrom<I>,
124    i16: TryFrom<I>,
125    i32: TryFrom<I>,
126    i64: TryFrom<I>,
127    i128: TryFrom<I>,
128    u8: TryFrom<I>,
129    u16: TryFrom<I>,
130    u32: TryFrom<I>,
131    u64: TryFrom<I>,
132    u128: TryFrom<I>,
133{
134    impl_cast_body!(integer, cast, input, to_type)
135}
136
137/// Casts a scalar literal to the given literal type.
138fn cast_scalar_to_type<N: Network>(input: &Scalar<N>, to_type: LiteralType) -> Result<Literal<N>> {
139    impl_cast_body!(scalar, cast, input, to_type)
140}
snarkvm_console_program/data/literal/cast/mod.rs

snarkvm_console_program/data/literal/cast/
mod.rs
