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/* This file is dedicated to the public domain. */
#ifndef INC_VEC_H
#define INC_VEC_H
#include <errno.h>
#include <stdlib.h>
#include "../intdefs.h"
struct _vec {
uint sz;
uint max;
void *data;
};
/*
* A dynamic array with push, pop and concatenate operations.
*
* Usage: struct VEC(my_type) myvec = {0};
* Or: struct myvec VEC(my_type);
* Or: typedef struct VEC(my_type) myvec;
*/
#define VEC(type) { \
uint sz; \
uint max; \
type *data; \
}
#if defined(__GNUC__) || defined(__clang__)
__attribute__((unused)) // heck off gcc
#endif
static bool _vec_ensure(struct _vec *v, uint tsize, uint newmax) {
// FIXME: potential overflow at least on 32-bit hosts (if any!?).
// should use reallocarray or something but didn't feel like porting right
// now. consider doing later.
void *new = realloc(v->data, tsize * newmax);
if (new) { v->data = new; v->max = newmax; }
return !!new;
}
#if defined(__GNUC__) || defined(__clang__)
__attribute__((unused)) // heck off gcc 2
#endif
static bool _vec_make_room(struct _vec *v, uint tsize, uint addcnt) {
// this overflow check is probably unnecessary, but just in case
u64 chk = v->max + addcnt;
if (chk > 1u << 30) { errno = ENOMEM; return false; }
u32 x = chk;
if (x < 16) {
x = 16;
}
else {
// round up to next 2*n
--x;
x |= x >> 1; x |= x >> 2; x |= x >> 4; x |= x >> 8; x |= x >> 16;
x++;
}
return _vec_ensure(v, tsize, x);
}
// internal: for reuse by vec0
#define _vec_push(v, val, slack) ( \
((v)->sz + (slack) < (v)->max || \
_vec_make_room((struct _vec *)(v), sizeof(val), 1)) && \
((v)->data[(v)->sz++ - slack] = (val), true) \
)
#define _vec_pushall(v, vals, n, slack) ( \
((v)->sz + (n) + (slack) <= (v)->max || \
_vec_make_room((struct _vec *)(v), sizeof(*(vals)), (n))) && \
(memcpy((v)->data + (v)->sz - (slack), (vals), (n) * sizeof(*(vals))), \
(v)->sz += (n), true) \
)
/*
* Appends an item to the end of a vector. Gives true on success and false if
* memory allocation fails.
*/
#define vec_push(v, val) _vec_push(v, val, 0)
/*
* Appends n items from an array to the end of a vector. Gives true on success
* and false if memory allocation fails.
*/
#define vec_pushall(v, vals, n) _vec_pushall(v, vals, n, 0)
/*
* Removes an item from the end of a vector and gives that item.
*/
#define vec_pop(v) ((v)->data[--(v)->sz])
#endif
// vi: sw=4 ts=4 noet tw=80 cc=80
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