safe_decimal_core 0.1.1

This is a Rust fixed-point numeric library targeting blockchain development. Originally created and used as a part of the Invariant Protocol. The current version leverages macros, traits and generics to exchange dozens of lines of error prone code with a single line and generating the rest.
Documentation 
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

use quote::quote;

use crate::utils::string_to_ident;
use crate::DecimalCharacteristics;

pub fn generate_big_ops(characteristics: DecimalCharacteristics) -> proc_macro::TokenStream {
    let DecimalCharacteristics {
        struct_name,
        big_type,
        underlying_type,
        ..
    } = characteristics;

    let name_str = &struct_name.to_string();
    let underlying_str = &underlying_type.to_string();
    let big_str = &big_type.to_string();

    let module_name = string_to_ident("tests_big_ops_", &name_str);

    proc_macro::TokenStream::from(quote!(
        impl<T: Decimal> BigOps<T> for #struct_name
        where
            T::U: TryInto<#big_type>,
        {
            fn big_mul(self, rhs: T) -> Self {
                Self::new(
                    #big_type::try_from(self.get())
                        .unwrap_or_else(|_| std::panic!("decimal: lhs value can't fit into `{}` type in {}::big_mul()", #big_str, #name_str))
                        .checked_mul(
                            rhs.get()
                                .try_into()
                                .unwrap_or_else(|_| std::panic!("decimal: rhs value can't fit into `{}` type in {}::big_mul()", #big_str, #name_str))
                        )
                        .unwrap_or_else(|| std::panic!("decimal: overflow in method {}::big_mul()", #name_str))
                        .checked_div(
                            T::one()
                        )
                        .unwrap_or_else(|| std::panic!("decimal: overflow in method {}::big_mul()", #name_str))
                        .try_into()
                        .unwrap_or_else(|_| std::panic!("decimal: overflow casting result to `{}` type in method {}::big_mul()", #underlying_str, #name_str))

                )
            }

            fn big_mul_up(self, rhs: T) -> Self {
                Self::new(
                    #big_type::try_from(self.get())
                        .unwrap_or_else(|_| std::panic!("decimal: lhs value can't fit into `{}` type in {}::big_mul_up()", #big_str, #name_str))
                        .checked_mul(
                            rhs.get()
                                .try_into()
                                .unwrap_or_else(|_| std::panic!("decimal: rhs value can't fit into `{}` type in {}::big_mul_up()", #big_str, #name_str))
                        )
                        .unwrap_or_else(|| std::panic!("decimal: overflow in method {}::big_mul_up()", #name_str))
                        .checked_add(T::almost_one())
                        .unwrap_or_else(|| std::panic!("decimal: overflow in method {}::big_mul_up()", #name_str))
                        .checked_div(
                            T::one()
                        )
                        .unwrap_or_else(|| std::panic!("decimal: overflow in method {}::big_mul_up()", #name_str))
                        .try_into()
                        .unwrap_or_else(|_| std::panic!("decimal: overflow casting result to `{}` type in method {}::big_mul_up()", #underlying_str, #name_str))
                )
            }

            fn big_div(self, rhs: T) -> Self {
                Self::new(
                    #big_type::try_from(self.get())
                        .unwrap_or_else(|_| std::panic!("decimal: lhs value can't fit into `{}` type in {}::big_div()", #big_str, #name_str))
                        .checked_mul(
                            T::one()
                        )
                        .unwrap_or_else(|| std::panic!("decimal: overflow in method {}::big_div()", #name_str))
                        .checked_div(
                            rhs.get()
                                .try_into()
                                .unwrap_or_else(|_| std::panic!("decimal: rhs value can't fit into `{}` type in {}::big_div()", #big_str, #name_str))
                        )
                        .unwrap_or_else(|| std::panic!("decimal: overflow in method {}::big_div()", #name_str))
                        .try_into()
                        .unwrap_or_else(|_| std::panic!("decimal: overflow casting result to `{}` type in method {}::big_div()", #underlying_str, #name_str))
                )
            }

            fn big_div_up(self, rhs: T) -> Self {
                Self::new(
                    #big_type::try_from(self.get())
                        .unwrap_or_else(|_| std::panic!("decimal: lhs value can't fit into `{}` type in {}::big_div_up()", #big_str, #name_str))
                        .checked_mul(
                            T::one()
                        )
                        .unwrap_or_else(|| std::panic!("decimal: overflow in method {}::big_div_up()", #name_str))
                        .checked_add(
                            rhs.get()
                                .try_into()
                                .unwrap_or_else(|_| std::panic!("decimal: rhs value can't fit into `{}` type in {}::big_div_up()", #big_str, #name_str))
                                .checked_sub(#big_type::from(1u128)).unwrap()
                        )
                        .unwrap_or_else(|| std::panic!("decimal: overflow in method {}::big_div_up()", #name_str))
                        .checked_div(
                            rhs.get()
                                .try_into().unwrap_or_else(|_| std::panic!("rhs value could not be converted to big type in `big_div_up`")),
                        )
                        .unwrap_or_else(|| std::panic!("decimal: overflow in method {}::big_div_up()", #name_str))
                        .try_into()
                        .unwrap_or_else(|_| std::panic!("decimal: overflow casting result to `{}` type in method {}::big_div_up()", #underlying_str, #name_str))
                )
            }
        }

        #[cfg(test)]
        pub mod #module_name {
            use super::*;

            #[test]
            fn test_big_mul () {
                let a = #struct_name::new(2);
                let b = #struct_name::new(#struct_name::one());
                assert_eq!(a.big_mul(b), #struct_name::new(2));
            }

            #[test]
            fn test_big_mul_up () {
                let a = #struct_name::new(2);
                let b = #struct_name::new(#struct_name::one());
                assert_eq!(a.big_mul_up(b), #struct_name::new(2));
            }

            #[test]
            fn test_big_div () {
                let a = #struct_name::new(2);
                let b = #struct_name::new(#struct_name::one());
                assert_eq!(a.big_div(b), #struct_name::new(2));
            }

            #[test]
            fn test_big_div_up () {
                let a = #struct_name::new(2);
                let b = #struct_name::new(#struct_name::one());
                assert_eq!(a.big_div_up(b), #struct_name::new(2));
            }
        }
    ))
}