1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148

// Copyright (C) 2019-2022 Aleo Systems Inc.
// This file is part of the snarkVM library.

// The snarkVM library is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// The snarkVM library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with the snarkVM library. If not, see <https://www.gnu.org/licenses/>.

mod input;
use input::*;

mod output;
use output::*;

mod bytes;
mod parse;

use crate::Instruction;
use console::{
    network::prelude::*,
    program::{Identifier, Register},
};

use indexmap::IndexSet;

#[derive(Clone, PartialEq, Eq)]
pub struct Closure<N: Network> {
    /// The name of the closure.
    name: Identifier<N>,
    /// The input statements, added in order of the input registers.
    /// Input assignments are ensured to match the ordering of the input statements.
    inputs: IndexSet<Input<N>>,
    /// The instructions, in order of execution.
    instructions: Vec<Instruction<N>>,
    /// The output statements, in order of the desired output.
    outputs: IndexSet<Output<N>>,
}

impl<N: Network> Closure<N> {
    /// Initializes a new closure with the given name.
    pub fn new(name: Identifier<N>) -> Self {
        Self { name, inputs: IndexSet::new(), instructions: Vec::new(), outputs: IndexSet::new() }
    }

    /// Returns the name of the closure.
    pub const fn name(&self) -> &Identifier<N> {
        &self.name
    }

    /// Returns the closure inputs.
    pub const fn inputs(&self) -> &IndexSet<Input<N>> {
        &self.inputs
    }

    /// Returns the closure instructions.
    pub fn instructions(&self) -> &[Instruction<N>] {
        &self.instructions
    }

    /// Returns the closure outputs.
    pub const fn outputs(&self) -> &IndexSet<Output<N>> {
        &self.outputs
    }
}

impl<N: Network> Closure<N> {
    /// Adds the input statement to the closure.
    ///
    /// # Errors
    /// This method will halt if there are instructions or output statements already.
    /// This method will halt if the maximum number of inputs has been reached.
    /// This method will halt if the input statement was previously added.
    #[inline]
    fn add_input(&mut self, input: Input<N>) -> Result<()> {
        // Ensure there are no instructions or output statements in memory.
        ensure!(self.instructions.is_empty(), "Cannot add inputs after instructions have been added");
        ensure!(self.outputs.is_empty(), "Cannot add inputs after outputs have been added");

        // Ensure the maximum number of inputs has not been exceeded.
        ensure!(self.inputs.len() <= N::MAX_INPUTS, "Cannot add more than {} inputs", N::MAX_INPUTS);
        // Ensure the input statement was not previously added.
        ensure!(!self.inputs.contains(&input), "Cannot add duplicate input statement");

        // Ensure the input register is a locator.
        ensure!(matches!(input.register(), Register::Locator(..)), "Input register must be a locator");

        // Insert the input statement.
        self.inputs.insert(input);
        Ok(())
    }

    /// Adds the given instruction to the closure.
    ///
    /// # Errors
    /// This method will halt if the maximum number of instructions has been reached.
    #[inline]
    pub fn add_instruction(&mut self, instruction: Instruction<N>) -> Result<()> {
        // Ensure the maximum number of instructions has not been exceeded.
        ensure!(
            self.instructions.len() <= N::MAX_INSTRUCTIONS,
            "Cannot add more than {} instructions",
            N::MAX_INSTRUCTIONS
        );

        // Ensure the destination register is a locator.
        for register in instruction.destinations() {
            ensure!(matches!(register, Register::Locator(..)), "Destination register must be a locator");
        }

        // Insert the instruction.
        self.instructions.push(instruction);
        Ok(())
    }

    /// Adds the output statement to the closure.
    ///
    /// # Errors
    /// This method will halt if there are no instructions in memory.
    /// This method will halt if the maximum number of outputs has been reached.
    #[inline]
    fn add_output(&mut self, output: Output<N>) -> Result<()> {
        // Ensure there are instructions in memory.
        ensure!(!self.instructions.is_empty(), "Cannot add outputs before instructions have been added");

        // Ensure the maximum number of outputs has not been exceeded.
        ensure!(self.outputs.len() <= N::MAX_OUTPUTS, "Cannot add more than {} outputs", N::MAX_OUTPUTS);

        // Insert the output statement.
        self.outputs.insert(output);
        Ok(())
    }
}

impl<N: Network> TypeName for Closure<N> {
    /// Returns the type name as a string.
    #[inline]
    fn type_name() -> &'static str {
        "closure"
    }
}