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https://github.com/dapphub/ds-math
Safe arithmetic
https://github.com/dapphub/ds-math
arithmetic dappsys ethereum solidity
Last synced: about 16 hours ago
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Safe arithmetic
- Host: GitHub
- URL: https://github.com/dapphub/ds-math
- Owner: dapphub
- License: gpl-3.0
- Created: 2017-03-29T22:49:28.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2022-07-29T06:41:05.000Z (over 2 years ago)
- Last Synced: 2023-11-07T16:09:14.668Z (about 1 year ago)
- Topics: arithmetic, dappsys, ethereum, solidity
- Language: Solidity
- Homepage: https://dapp.tools/dappsys/ds-math.html
- Size: 48.8 KB
- Stars: 243
- Watchers: 16
- Forks: 57
- Open Issues: 7
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
DSMath
_Safe Arithmetic_
DS-Math provides arithmetic functions for the common numerical primitive types
of Solidity. You can safely add, subtract, multiply, and divide `uint` numbers
without fear of integer overflow. You can also find the minimum and maximum of
two numbers.
Additionally, this package provides arithmetic functions for new two higher
level numerical concepts called wad (18 decimals) and ray (27 decimals). These
are used to represent fixed-point decimal numbers.
A wad is a decimal number with 18 digits of precision and a ray is a decimal
number with 27 digits of precision. These functions are necessary to account for
the difference between how integer arithmetic behaves normally, and how decimal
arithmetic should actually work. A brief example using `wmul`, which returns the
product of a wad and another number:
```solidity
1.1 * 2.2 == 2.42
//Regular integer arithmetic adds orders of magnitude:
110 * 220 == 24200
// Wad arithmetic does not add orders of magnitude:
wmul(1.1 ether, 2.2 ether) == 2.42 ether
```
### Naming Convention
The standard functions are the `uint` set, so their function names are not
prefixed: `add`, `sub`, `mul`, `min`, and `max`. There is no `div` function, as
divide-by-zero checking is built into the Solidity compiler.
The `int` functions have an `i` prefix: `imin`, and `imax`.
Wad functions have a `w` prefix: `wmul`, `wdiv`.
Ray functions have a `r` prefix: `rmul`, `rdiv`, `rpow`.
### API Reference
#### `add`
Return `x + y` or an exception in case of `uint` overflow.
#### `sub`
Return `x - y` or an exception in case of `uint` overflow.
#### `mul`
Return `x * y` or an exception in case of `uint` overflow.
#### `min`
Return the smaller number of `x` and `y`.
#### `max`
Return the larger number of `x` and `y`.
#### `imin`
Return the smaller number of `x` and `y`.
#### `imax`
Return the larger number of `x` and `y`.
#### `wmul`
Multiply two Wads and return a new Wad with the correct level of precision. A
Wad is a decimal number with 18 digits of precision that is being represented
as an integer.
#### `wdiv`
Divide two Wads and return a new Wad with the correct level of precision. A
Wad is a decimal number with 18 digits of precision that is being represented
as an integer.
#### `rmul`
Multiply two Rays and return a new Ray with the correct level of precision. A
Ray is a decimal number with 27 digits of precision that is being represented
as an integer.
#### `rdiv`
Divide two Rays and return a new Ray with the correct level of precision. A
Ray is a decimal number with 27 digits of precision that is being represented
as an integer.
#### `rpow`
Raise a Ray to the n^th power and return a new Ray with the correct level of
precision. A Ray is a decimal number with 27 digits of precision that is being
represented as an integer.