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/* $NetBSD: fmemopen.c,v 1.4 2010/09/27 16:50:13 tnozaki Exp $ */
/*-
* Copyright (c)2007, 2010 Takehiko NOZAKI,
* Copyright (c) 2012, Venkatesh Srinivas <vsrinivas@dragonflybsd.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/param.h>
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include "local.h"
#include "priv_stdio.h"
struct fmemopen_cookie {
char *head, *tail, *cur, *eob;
};
static int
fmemopen_read(void *cookie, char *buf, int nbytes)
{
struct fmemopen_cookie *p;
char *s;
int len;
assert(cookie != NULL);
assert(buf != NULL && nbytes > 0);
p = cookie;
s = p->cur;
len = MIN(p->tail - p->cur, nbytes);
bcopy(p->cur, buf, len);
p->cur += len;
return (int)(p->cur - s);
}
static int
fmemopen_write(void *cookie, const char *buf, int nbytes)
{
struct fmemopen_cookie *p;
char *s;
int len;
assert(cookie != NULL);
assert(buf != NULL && nbytes > 0);
p = cookie;
if (p->cur >= p->tail)
return 0;
s = p->cur;
len = MIN(p->tail - p->cur, nbytes);
bcopy(buf, p->cur, len);
p->cur += len - 1;
if (p->cur == p->tail - 1) {
*p->cur = '\0';
if (buf[len - 1] == '\0')
p->cur++;
} else {
*++p->cur = '\0';
}
if (p->cur > p->eob)
p->eob = p->cur;
return (int)(p->cur - s);
}
static fpos_t
fmemopen_seek(void *cookie, fpos_t offset, int whence)
{
struct fmemopen_cookie *p;
assert(cookie != NULL);
p = (struct fmemopen_cookie *)cookie;
switch (whence) {
case SEEK_SET:
break;
case SEEK_CUR:
offset += p->cur - p->head;
break;
case SEEK_END:
offset += p->eob - p->head;
break;
default:
errno = EINVAL;
goto error;
}
if (offset >= (fpos_t)0 && offset <= p->tail - p->head) {
p->cur = p->head + (ptrdiff_t)offset;
return (fpos_t)(p->cur - p->head);
}
error:
return (fpos_t)-1;
}
static int
fmemopen_close0(void *cookie)
{
assert(cookie != NULL);
free(cookie);
return 0;
}
static int
fmemopen_close1(void *cookie)
{
struct fmemopen_cookie *p;
assert(cookie != NULL);
p = cookie;
free(p->head);
free(p);
return 0;
}
FILE *
fmemopen(void * __restrict buf, size_t size, const char * __restrict mode)
{
int flags, oflags;
FILE *fp;
struct fmemopen_cookie *cookie;
if (size < (size_t)1)
goto invalid;
flags = __sflags(mode, &oflags);
if (flags == 0)
return NULL;
if ((oflags & O_RDWR) == 0 && buf == NULL)
goto invalid;
fp = __sfp();
if (fp == NULL)
return NULL;
cookie = malloc(sizeof(*cookie));
if (cookie == NULL)
goto release;
if (buf == NULL) {
cookie->head = malloc(size);
if (cookie->head == NULL) {
free(cookie);
goto release;
}
*cookie->head = '\0';
fp->_close = &fmemopen_close1;
} else {
cookie->head = (char *)buf;
if (oflags & O_TRUNC)
*cookie->head = '\0';
fp->_close = &fmemopen_close0;
}
cookie->tail = cookie->head + size;
cookie->eob = cookie->head;
do {
if (*cookie->eob == '\0')
break;
++cookie->eob;
} while (--size > 0);
cookie->cur = (oflags & O_APPEND) ? cookie->eob : cookie->head;
fp->pub._flags = flags;
fp->_write = (flags & __SRD) ? NULL : &fmemopen_write;
fp->_read = (flags & __SWR) ? NULL : &fmemopen_read;
fp->_seek = &fmemopen_seek;
fp->_cookie = (void *)cookie;
return fp;
invalid:
errno = EINVAL;
return NULL;
release:
fp->pub._flags = 0;
return NULL;
}
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