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author | Thomas Voss <mail@thomasvoss.com> | 2023-12-09 23:22:12 +0100 |
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committer | Thomas Voss <mail@thomasvoss.com> | 2023-12-09 23:22:12 +0100 |
commit | 63ae64d8bf7fa06eecfc2c50e3999800720c9173 (patch) | |
tree | 386fa41b00ecec4cc060827d42bba83dfcaa039f /da.h |
Genesis commit
Diffstat (limited to 'da.h')
-rw-r--r-- | da.h | 97 |
1 files changed, 97 insertions, 0 deletions
@@ -0,0 +1,97 @@ +/* + * Simple & stupid dynamic array single-header implementation. You can use the + * macros defined in this file with any structure that has the following fields: + * + * struct dyn_array { + * T *buf // Array of items + * N len // Length of array + * N cap // Capacity of array + * } + * + * The type ‘T’ is whatever type you want to store. The type ‘N’ is any numeric + * type — most likely ‘size_t’ — but it could be sized as well. + * + * You should include ‘err.h’ and ‘stdlib.h’ along with this file. If you want + * to use da_remove(), include ‘string.h’. The da_remove() macro also doesn’t + * bother with shrinking your array when the length is far lower than the + * capacity. If you care about that, do it yourself. + * + * Remember to call free() on your dynamic arrays ‘buf’ field after use. + * + * Macro Overview + * ―――――――――――――― + * The argument ‘a’ to all of the below macros is a pointer to the dynamic array + * structure. + * + * da_init(a, n) Initialize the array with a capacity of ‘n’ items. + * da_append(a, x) Append the item ‘x’ to the array + * da_remove(a, x) Remove the item ‘x’ from the array + * da_remove_range(a, x, y) Remove the items between the range [x, y) + * + * The ‘da_append()’ macro will by default double the arrays capacity when it + * gets full. If you would like to use a different growth factor instead of 2, + * you can define the DA_FACTOR macro to your desired growth factor before + * including this file. + * + * + * Example + * ――――――― + * + * struct { + * int *buf; + * size_t len, cap; + * } nums; + * + * // Initialize nums with capacity == 4 + * da_init(&nums, 4); + * + * // Append 69, 1337, and 420 to nums + * da_append(&nums, 69); + * da_append(&nums, 1337); + * da_append(&nums, 420); + * + * // Remove 1337 and 420 from nums + * da_remove_range(&nums, 1, 3); + * + * // Remove 69 from nums + * da_remove(&nums, 0); + */ + +#ifndef MANGO_DA_H +#define MANGO_DA_H + +#ifndef DA_FACTOR +# define DA_FACTOR 2 +#endif + +#define __da_s(a) (sizeof(*(a)->buf)) + +#define da_init(a, n) \ + do { \ + (a)->cap = n; \ + (a)->len = 0; \ + (a)->buf = malloc((a)->cap * __da_s(a)); \ + if ((a)->buf == NULL) \ + err(EXIT_FAILURE, "malloc"); \ + } while (0) + +#define da_append(a, x) \ + do { \ + if ((a)->len >= (a)->cap) { \ + (a)->cap = (a)->cap * DA_FACTOR + 1; \ + (a)->buf = realloc((a)->buf, (a)->cap * __da_s(a)); \ + if ((a)->buf == NULL) \ + err(EXIT_FAILURE, "realloc"); \ + } \ + (a)->buf[(a)->len++] = (x); \ + } while (0) + +#define da_remove(a, i) da_remove_range((a), (i), (i) + 1) + +#define da_remove_range(a, i, j) \ + do { \ + memmove((a)->buf + (i), (a)->buf + (j), ((a)->len - (j)) * __da_s(a)); \ + (a)->len -= j - i; \ + } while (0) + +#endif /* !MANGO_DA_H */ |