Dynamic Arrays¶

abs_dynarray is a generic, byte-memory dynamic array. You tell it the element size once; it stores raw bytes and grows automatically. It can hold any POD type, and is the workhorse data structure used internally by the runtime.

#include "abscom/abs.h"

Types¶

typedef struct abs_dynarray {
    void  *data;
    size_t elem_size;
    size_t len;
    size_t cap;
} abs_dynarray_t;

Field	Meaning
`data`	The backing buffer (`NULL` when empty).
`elem_size`	Size of one element in bytes.
`len`	Number of elements currently stored.
`cap`	Number of elements the buffer can hold before growing.

API¶

Function	Description
`int abs_dynarray_init(abs_dynarray_t *arr, size_t elem_size)`	Initialize an array with a fixed element size.
`void abs_dynarray_destroy(abs_dynarray_t *arr)`	Free the backing buffer.
`void abs_dynarray_clear(abs_dynarray_t *arr)`	Set the length to zero, keeping capacity.
`int abs_dynarray_reserve(abs_dynarray_t *arr, size_t cap)`	Ensure capacity for at least `cap` elements.
`int abs_dynarray_push(abs_dynarray_t arr, const void elem)`	Append a copy of `elem`.
`void abs_dynarray_pop(abs_dynarray_t *arr)`	Remove the last element.
`int abs_dynarray_resize(abs_dynarray_t *arr, size_t new_len)`	Resize; newly added slots are zero-filled.
`void abs_dynarray_at(abs_dynarray_t arr, size_t index)`	Pointer to element `index`, or `NULL` if out of range.
`const void abs_dynarray_at_const(const abs_dynarray_t arr, size_t index)`	Const variant of `abs_dynarray_at`.
`void abs_dynarray_data(abs_dynarray_t arr)`	The raw backing buffer.
`size_t abs_dynarray_len(const abs_dynarray_t *arr)`	Number of elements.
`size_t abs_dynarray_cap(const abs_dynarray_t *arr)`	Allocated capacity in elements.

Functions that can fail return 0 on success and -1 on error.

Example¶

#include "abscom/abs.h"
#include <stdio.h>

int main(void) {
    abs_dynarray_t arr;
    abs_dynarray_init(&arr, sizeof(int));

    for (int i = 0; i < 100; i++) abs_dynarray_push(&arr, &i);

    printf("len=%zu cap=%zu\n", abs_dynarray_len(&arr), abs_dynarray_cap(&arr));
    int *first = (int *)abs_dynarray_at(&arr, 0);
    int *last  = (int *)abs_dynarray_at(&arr, 99);
    printf("first=%d last=%d\n", *first, *last);   /* 0 99 */

    abs_dynarray_destroy(&arr);
    return 0;
}

Memory note: the array copies elem_size bytes per push, so it is your job to manage any heap memory the elements point to. abs_dynarray_destroy frees only the buffer itself.

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