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