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/*
* 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. To use the da_foreach()
* macro, you need to have ptrdiff_t defined; to be absolutely sure you can
* include ‘stddef.h’.
*
* 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.
*
* dainit(a, n) Initialize the array with a capacity of ‘n’ items.
* dapush(a, x) Append the item ‘x’ to the array
* daremove(a, x) Remove the item ‘x’ from the array
* da_remove_range(a, x, y) Remove the items between the range [x, y)
* da_foreach(a, p) Iterate the pointer ‘p’ over each element of the
* array. The type of ‘p’ is inferred.
*
* The ‘dapush()’ macro will by double the arrays capacity when it gets full.
* If you would like your arrays to grow with a different scale, edit this file.
*
*
* Example
* ―――――――
*
* struct {
* int *buf;
* size_t len, cap;
* } nums;
*
* // Initialize nums with capacity == 4
* dainit(&nums, 4);
*
* // Append 69, 1337, and 420 to nums
* dapush(&nums, 69);
* dapush(&nums, 1337);
* dapush(&nums, 420);
*
* da_foreach (&nums, n) {
* int x = *n << 1;
* printf("n = %d; n² = %d\n", *n, x);
* }
*
* // Remove 1337 and 420 from nums
* da_remove_range(&nums, 1, 3);
*
* // Remove 69 from nums
* daremove(&nums, 0);
*/
#ifndef MANGO_DA_H
#define MANGO_DA_H
#define DA_ALLOC(p, n) \
do { \
if ((n) && SIZE_MAX / (n) < sizeof(*(p))) { \
errno = EOVERFLOW; \
err(EXIT_FAILURE, "realloc"); \
} \
if (!((p) = realloc((p), (n) * sizeof(*(p))))) \
err(EXIT_FAILURE, "realloc"); \
} while (0)
#define dainit(a, n) \
do { \
(a)->buf = NULL; \
(a)->cap = n; \
(a)->len = 0; \
DA_ALLOC((a)->buf, (a)->cap); \
} while (0)
#define dapush(a, x) \
do { \
if ((a)->len >= (a)->cap) { \
(a)->cap = (a)->cap ? (a)->cap * 2 : 1; \
DA_ALLOC((a)->buf, (a)->cap); \
} \
(a)->buf[(a)->len++] = (x); \
} while (0)
#define daremove(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)) * sizeof(*(a)->buf)); \
(a)->len -= j - i; \
} while (0)
#define da_foreach(a, p) \
for (auto p = (a)->buf; p - (a)->buf < (ptrdiff_t)(a)->len; p++)
#endif /* !MANGO_DA_H */
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