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/*-
* Copyright (c) 2013 Advanced Computing Technologies LLC
* Written by: John H. Baldwin <jhb@FreeBSD.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/cdefs.h>
#include <assert.h>
#include <errno.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <wchar.h>
/* XXX: There is no FPOS_MAX. This assumes fpos_t is an off_t. */
#define FPOS_MAX OFF_MAX
struct memstream {
char **bufp;
size_t *sizep;
ssize_t len;
fpos_t offset;
};
static int
memstream_grow(struct memstream *ms, fpos_t newoff)
{
char *buf;
ssize_t newsize;
if (newoff < 0 || newoff >= SSIZE_MAX)
newsize = SSIZE_MAX - 1;
else
newsize = newoff;
if (newsize > ms->len) {
buf = realloc(*ms->bufp, newsize + 1);
if (buf != NULL) {
memset(buf + ms->len + 1, 0, newsize - ms->len);
*ms->bufp = buf;
ms->len = newsize;
return (1);
}
return (0);
}
return (1);
}
static void
memstream_update(struct memstream *ms)
{
assert(ms->len >= 0 && ms->offset >= 0);
*ms->sizep = ms->len < ms->offset ? ms->len : ms->offset;
}
static int
memstream_write(void *cookie, const char *buf, int len)
{
struct memstream *ms;
ssize_t tocopy;
ms = cookie;
if (!memstream_grow(ms, ms->offset + len))
return (-1);
tocopy = ms->len - ms->offset;
if (len < tocopy)
tocopy = len;
memcpy(*ms->bufp + ms->offset, buf, tocopy);
ms->offset += tocopy;
memstream_update(ms);
return (tocopy);
}
static fpos_t
memstream_seek(void *cookie, fpos_t pos, int whence)
{
struct memstream *ms;
#ifdef DEBUG
fpos_t old;
#endif
ms = cookie;
#ifdef DEBUG
old = ms->offset;
#endif
switch (whence) {
case SEEK_SET:
/* _fseeko() checks for negative offsets. */
assert(pos >= 0);
ms->offset = pos;
break;
case SEEK_CUR:
/* This is only called by _ftello(). */
assert(pos == 0);
break;
case SEEK_END:
if (pos < 0) {
if (pos + ms->len < 0) {
errno = EINVAL;
return (-1);
}
} else {
if (FPOS_MAX - ms->len < pos) {
errno = EOVERFLOW;
return (-1);
}
}
ms->offset = ms->len + pos;
break;
}
memstream_update(ms);
return (ms->offset);
}
static int
memstream_close(void *cookie)
{
free(cookie);
return (0);
}
FILE *
open_memstream(char **bufp, size_t *sizep)
{
struct memstream *ms;
int save_errno;
FILE *fp;
if (bufp == NULL || sizep == NULL) {
errno = EINVAL;
return (NULL);
}
*bufp = calloc(1, 1);
if (*bufp == NULL)
return (NULL);
ms = malloc(sizeof(*ms));
if (ms == NULL) {
save_errno = errno;
free(*bufp);
*bufp = NULL;
errno = save_errno;
return (NULL);
}
ms->bufp = bufp;
ms->sizep = sizep;
ms->len = 0;
ms->offset = 0;
memstream_update(ms);
fp = funopen(ms, NULL, memstream_write, memstream_seek,
memstream_close);
if (fp == NULL) {
save_errno = errno;
free(ms);
free(*bufp);
*bufp = NULL;
errno = save_errno;
return (NULL);
}
fwide(fp, -1);
return (fp);
}
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