cosmopolitan/libc/mem/balloc.c

45 lines
2.8 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ This program is free software; you can redistribute it and/or modify │
│ it under the terms of the GNU General Public License as published by │
│ the Free Software Foundation; version 2 of the License. │
│ │
│ This program is distributed in the hope that it will be useful, but │
│ WITHOUT ANY WARRANTY; without even the implied warranty of │
│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
│ General Public License for more details. │
│ │
│ You should have received a copy of the GNU General Public License │
│ along with this program; if not, write to the Free Software │
│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
│ 02110-1301 USA │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/mem/mem.h"
#include "libc/runtime/buffer.h"
/* TODO(jart): Delete */
#define kGuard PAGESIZE
#define kGrain FRAMESIZE
/**
* Allocates page-guarded buffer.
*
* ┌─────────────────────────────────────┬s─i─g─s─e─g─v┐
* │ 𝑣₀..𝑣ₙ₋₁ │𝑣ₙ..𝑣ₙ₊₄₀₉₆₋₁│
* └─────────────────────────────────────┴s─i─g─s─e─g─v┘
*
* @param b is metadata object owned by caller, initialized to zero for
* first call; subsequent calls will resize
* @param a is alignment requirement in bytes, e.g. 1,2,4,8,16,...
* @param n is buffer size in bytes
* @return b->p
* @see ralloc()
*/
void *balloc(struct GuardedBuffer *b, unsigned a, size_t n) {
return (b->p = memalign(a, n));
}