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/*-*- 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/bits/bits.h"
#include "libc/bits/popcnt.h"
#include "libc/calls/calls.h"
#include "libc/errno.h"
#include "libc/mem/mem.h"
#include "libc/runtime/runtime.h"
#include "libc/stdio/stdio.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/o.h"
#include "libc/sysv/errfuns.h"
/**
* Opens buffer as stream.
*
* This function is the heart of the streams implementation, and it's
* truly magnificent for unit testing.
*
* @param buf becomes owned by this function, and is allocated if NULL
* @return new stream or NULL w/ errno
* @error ENOMEM, EINVAL
*/
FILE *fmemopen(void *buf, size_t size, const char *mode) {
FILE *res;
unsigned flags;
if (buf && !size) {
einval();
return NULL;
}
if (size && popcnt(size) != 1) {
einval();
return NULL;
}
if (!(res = calloc(1, sizeof(FILE)))) {
return NULL;
}
if (!buf) {
if (!size) size = FRAMESIZE;
if (!(buf = valloc(size))) {
free(res);
return NULL;
}
}
res->fd = -1;
setbuffer(res, buf, size);
res->bufmode = res->buf ? _IOFBF : _IONBF;
flags = fopenflags(mode);
res->iomode = (flags & O_ACCMODE) == O_RDWR
? O_RDWR
: (flags & O_ACCMODE) == O_WRONLY ? O_WRONLY : O_RDONLY;
return res;
}