anchor_safe_math/
lib.rs

1//! # Anchor Safe Math
2//!
3//! `anchor_safe_math` is a collection of helper numeric operation functions that removes the 
4//! verbosity of checking for overflow, underflow and division by zero errors.
5//! 
6//! # Examples
7//!
8//! ```
9//! use anchor_lang::prelude::;
10//! use anchor_safe_math::{SafeMath};
11//! 
12//! #[program]
13//! pub mod example {
14//!   use super::*;
15//! 
16//!   pub fn instruction(ctx: Context<Instruction>, amount: u64) -> ProgramResult {
17//!     let state = &mut ctx.accounts.state;
18//! 
19//!     // You can apply any of the following operations
20//!     state.total_amount = state.total_amount.safe_add(amount)?;
21//!     state.total_amount = state.total_amount.safe_sub(amount)?;
22//!     state.total_amount = state.total_amount.safe_mul(amount)?;
23//!     state.total_amount = state.total_amount.safe_div(amount)?;
24//!     state.total_amount = state.total_amount.safe_pow(8_u32)?;
25//!   }
26//! }
27//! 
28//! #[derive(Accounts)]
29//! pub struct Instruction<'info> {
30//!   ...
31//! }
32//! ```
33use anchor_lang::prelude::{
34  error, error_code, ProgramError,
35};
36use std::result::Result as StdResult;
37
38#[error_code]
39/// Errors that can be triggered by executing one of the supported numeric operations
40pub enum ErrorCode {
41  #[msg("overflow")]
42  Overflow,
43  #[msg("underflow")]
44  Underflow,
45  #[msg("division by zero")]
46  DivisionByZero,
47}
48
49/// Defines a set of safe math operations that return a `ProgramError` which is expected in an anchor instruction execution.
50pub trait SafeMath {
51  type Output;
52
53  fn safe_add(&self, rhs: Self::Output) -> StdResult<Self::Output, ProgramError>;
54  fn safe_sub(&self, rhs: Self::Output) -> StdResult<Self::Output, ProgramError>;
55  fn safe_div(&self, rhs: Self::Output) -> StdResult<Self::Output, ProgramError>;
56  fn safe_mul(&self, rhs: Self::Output) -> StdResult<Self::Output, ProgramError>;
57  fn safe_pow(&self, exp: u32) -> StdResult<Self::Output, ProgramError>;
58}
59
60macro_rules! safe_math {
61  ($type: ident) => {
62    /// $type implementation of the SafeMath trait
63    impl SafeMath for $type {
64      type Output = $type;
65
66      fn safe_add(&self, rhs: Self::Output) -> StdResult<Self::Output, ProgramError> {
67        match self.checked_add(rhs) {
68          Some(result) => Ok(result),
69          None => return Err(error!(ErrorCode::Overflow).into())
70        }
71      }
72    
73      fn safe_sub(&self, rhs: Self::Output) -> StdResult<Self::Output, ProgramError> {
74        match self.checked_sub(rhs) {
75          Some(result) => Ok(result),
76          None => return Err(error!(ErrorCode::Underflow).into())
77        }
78      }
79
80      fn safe_mul(&self, rhs: Self::Output) -> StdResult<Self::Output, ProgramError> {
81        match self.checked_mul(rhs) {
82          Some(result) => Ok(result),
83          None => return Err(error!(ErrorCode::Underflow).into())
84        }
85      }
86
87      fn safe_div(&self, rhs: Self::Output) -> StdResult<Self::Output, ProgramError> {
88        match self.checked_div(rhs) {
89          Some(result) => Ok(result),
90          None => return Err(error!(ErrorCode::DivisionByZero).into())
91        }
92      }
93
94      fn safe_pow(&self, exp: u32) -> StdResult<Self::Output, ProgramError> {
95        match self.checked_pow(exp) {
96          Some(result) => Ok(result),
97          None => return Err(error!(ErrorCode::Overflow).into())
98        }
99      }
100    }
101  }
102}
103
104safe_math!(u128);
105safe_math!(u64);
106safe_math!(u32);
107safe_math!(u16);
108safe_math!(u8);
anchor_safe_math/lib.rs

anchor_safe_math/
lib.rs
