https://github.com/rphii/c-lookup-table
Compile Time Generic Dynamic Lookup Table in C
https://github.com/rphii/c-lookup-table
c dynamic generic hash hashing lookup lookup-table lut table
Last synced: 8 months ago
JSON representation
Compile Time Generic Dynamic Lookup Table in C
- Host: GitHub
- URL: https://github.com/rphii/c-lookup-table
- Owner: rphii
- License: mit
- Created: 2023-09-03T13:21:22.000Z (about 2 years ago)
- Default Branch: main
- Last Pushed: 2024-08-22T23:49:24.000Z (about 1 year ago)
- Last Synced: 2024-12-27T11:22:45.586Z (9 months ago)
- Topics: c, dynamic, generic, hash, hashing, lookup, lookup-table, lut, table
- Language: C
- Homepage:
- Size: 1.65 MB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# Things may still change
# Very untested as of now
# c-lookup-table
Compile Time Generic Dynamic Lookup Table in C.
## First Things First
On it's own, no code is being compiled. You first have to include and implement a lookup table of your desires. For that, there are two macros.
```c
#include "lutd.h"
LUTD_INCLUDE(N, A, T, M);
LUTD_IMPLEMENT(N, A, T, M, H, C, F);
```
1. `N` - **N**ame - the resulting name of the lookup table struct
2. `A` - **A**bbreviation - functions get prefixed with that
3. `T` - **T**ype - the type of your elements within the lookup table
4. `M` - **M**ode - storage type, either `BY_VAL` (by value) or `BY_REF` (by reference)
4. `H` - **H**ash - provide a hashing function for your elements (required)
4. `C` - **C**ompare - provide a comparing function for your elements - if none provided, default to `memcmp`
5. `F` - **F**ree - provide a freeing function for your elements, if available
The lookup table only stores how many times something with an equal hash has been added.
If something was added a second time, it will only increase the count, and *not* copy the data into
the table.
## Examples
- [example int](examples/example_int.c) `BY_VAL`, no `C` and no `F` provided
- [example person](examples/example_person.c) `BY_REF`, `C` and `F` provided
- I used this lookup table in my [Timers interpreter](https://github.com/rphii/TimersInterpreter) (`BY_REF`, `C` provided but no `F` provided)
- This lookup table is extensively used in [c-nexus](https://github.com/rphii/c-nexus) and [c-file-tagger](https://github.com/rphii/c-file-tagger) and provides the base for my string [c-string](https://github.com/rphii/c-string).
- to compile run `make` (have to be in the examples directory)
- to clean run `make clean` (if you're on cygwin, run `OS= make clean`
## Design Considerations
- Both `BY_VAL` and `BY_REF` can be used on either basic types or (complex) structs.
## Metaprogramming
### Advantages
- Compiler optimized code
- Flexibility, reusability (generics / templates)
- Type safety
### Disadvantages
- Maintenance challenges
- Debugging difficulties
- Compilation overhead
## How to use it
### Available Functions
The `A##` means the `A` specified in the two macros.
- `A##_init` initialize lookup table
- `A##_add` add a value
- `A##_add_count` add a specified number of counts to a value
- `A##_del` delete a value
- `A##_has` check if a value exists
- `A##_find` find position `i` and `j` of a value (to access in lookup table: `N.buckets[i].items[j]`)
- `A##_free` free lookup table
- `A##_clear` clear lookup table (reset but don't free)
- `A##_dump` dump everything unsorted (`arr` is required, `counts` is optional)
- `A##_clear` check if table is empty
# todo so I don't forget
- `A##_join` and `A##_join_threaded` ...