https://github.com/sug0/bitmap
Bitmap C Library
https://github.com/sug0/bitmap
array bitmap bool c cpp efficient lib library memory simple small
Last synced: 6 months ago
JSON representation
Bitmap C Library
- Host: GitHub
- URL: https://github.com/sug0/bitmap
- Owner: sug0
- Created: 2017-10-27T20:09:16.000Z (over 8 years ago)
- Default Branch: master
- Last Pushed: 2017-10-31T20:49:53.000Z (over 8 years ago)
- Last Synced: 2025-10-04T16:58:25.926Z (7 months ago)
- Topics: array, bitmap, bool, c, cpp, efficient, lib, library, memory, simple, small
- Language: C
- Size: 4.88 KB
- Stars: 1
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
# Bitmap
A bitmap is a data structure that implements an array of booleans in a very
memory efficient way; albeit the time complexity of this implementation
isn't constant, given the fact cpu registers will store the same bytes in
them for a prolonged period of time with accesses restricted to the
same memory region, this data structure often outperforms others with
better time complexity.
# API
```c
typedef struct _bm {
uint8_t *bits;
size_t max_index;
} Bitmap_t;
extern void Bitmap_init(Bitmap_t *bm, size_t sz);
extern uint8_t Bitmap_at(Bitmap_t *bm, size_t index);
extern void Bitmap_set(Bitmap_t *bm, size_t index, uint8_t set_bit);
extern void Bitmap_free(Bitmap_t *bm);
```
# Example usage
```c
#include
#include
int main(void)
{
Bitmap_t bm;
/* initialize bitmap with 8 spaces */
Bitmap_init(&bm, 8);
/* set the first bit */
Bitmap_set(&bm, 0, 1);
/* set the third bit */
Bitmap_set(&bm, 2, 1);
/* set the last bit */
Bitmap_set(&bm, 7, 1);
/* print set bits */
for (int i = 0; i < 8; i++)
putchar((Bitmap_at(&bm, i)) ? '1' : '0');
putchar('\n');
/* free the allocated space in memory */
Bitmap_free(&bm);
return 0;
}
```