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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* June 23 2023, Christian Hopps <chopps@labn.net>
*
* Copyright (c) 2023, LabN Consulting, L.L.C.
*
*/
#include <zebra.h>
#include "darr.h"
#include "memory.h"
DEFINE_MTYPE_STATIC(LIB, DARR, "Dynamic Array");
static uint _msb(uint count)
{
uint bit = 0;
int msb = 0;
while (count) {
if (count & 1)
msb = bit;
count >>= 1;
bit += 1;
}
return msb;
}
static uint darr_next_count(uint count, size_t esize)
{
uint ncount;
if (esize > sizeof(long long) && count == 1)
/* treat like a pointer */
ncount = 1;
else {
uint msb = _msb(count);
ncount = 1ull << msb;
/* if the users count wasn't a pow2 make it the next pow2. */
if (ncount != count) {
assert(ncount < count);
ncount <<= 1;
if (esize < sizeof(long long) && ncount < 8)
ncount = 8;
}
}
return ncount;
}
static size_t darr_size(uint count, size_t esize)
{
return count * esize + sizeof(struct darr_metadata);
}
void *__darr_resize(void *a, uint count, size_t esize)
{
uint ncount = darr_next_count(count, esize);
size_t osz = (a == NULL) ? 0 : darr_size(darr_cap(a), esize);
size_t sz = darr_size(ncount, esize);
struct darr_metadata *dm = XREALLOC(MTYPE_DARR,
a ? _darr_meta(a) : NULL, sz);
if (sz > osz)
memset((char *)dm + osz, 0, sz - osz);
dm->cap = ncount;
return (void *)(dm + 1);
}
void *__darr_insert_n(void *a, uint at, uint count, size_t esize, bool zero)
{
struct darr_metadata *dm;
uint olen, nlen;
if (!a)
a = __darr_resize(NULL, at + count, esize);
dm = (struct darr_metadata *)a - 1;
olen = dm->len;
// at == 1
// count == 100
// olen == 2
/* see if the user is expanding first using `at` */
if (at >= olen)
nlen = at + count;
else
nlen = olen + count;
if (nlen > dm->cap) {
a = __darr_resize(a, nlen, esize);
dm = (struct darr_metadata *)a - 1;
}
#define _a_at(i) ((char *)a + ((i)*esize))
if (at < olen)
memmove(_a_at(at + count), _a_at(at), esize * (olen - at));
dm->len = nlen;
if (zero) {
if (at >= olen) {
at -= olen;
count += olen;
}
memset(_a_at(at), 0, esize * count);
}
return (void *)a;
#undef _a_at
}
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