#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <fcntl.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include "local.h"
struct fmemopen_cookie
{
char *buf;
bool own;
char bin;
size_t size;
size_t len;
size_t off;
};
static int fmemopen_read(void *cookie, char *buf, int nbytes);
static int fmemopen_write(void *cookie, const char *buf, int nbytes);
static fpos_t fmemopen_seek(void *cookie, fpos_t offset, int whence);
static int fmemopen_close(void *cookie);
FILE *
fmemopen(void * __restrict buf, size_t size, const char * __restrict mode)
{
struct fmemopen_cookie *ck;
FILE *f;
int flags, rc;
if (size == 0) {
errno = EINVAL;
return (NULL);
}
rc = __sflags(mode, &flags);
if (rc == 0) {
errno = EINVAL;
return (NULL);
}
if (!(flags & O_RDWR) && buf == NULL) {
errno = EINVAL;
return (NULL);
}
ck = malloc(sizeof(struct fmemopen_cookie));
if (ck == NULL) {
return (NULL);
}
ck->off = 0;
ck->size = size;
ck->own = ((ck->buf = buf) == NULL);
if (ck->own) {
ck->buf = malloc(size);
if (ck->buf == NULL) {
free(ck);
return (NULL);
}
}
if (ck->own || mode[0] == 'w') {
ck->buf[0] = '\0';
}
ck->bin = strchr(mode, 'b') != NULL;
switch (mode[0]) {
case 'a':
ck->off = ck->len = strnlen(ck->buf, ck->size);
break;
case 'r':
ck->len = size;
break;
case 'w':
ck->len = 0;
break;
}
f = funopen(ck,
flags & O_WRONLY ? NULL : fmemopen_read,
flags & O_RDONLY ? NULL : fmemopen_write,
fmemopen_seek, fmemopen_close);
if (f == NULL) {
if (ck->own)
free(ck->buf);
free(ck);
return (NULL);
}
if (mode[0] == 'a')
f->_flags |= __SAPP;
setvbuf(f, NULL, _IONBF, 0);
return (f);
}
static int
fmemopen_read(void *cookie, char *buf, int nbytes)
{
struct fmemopen_cookie *ck = cookie;
if (nbytes > ck->len - ck->off)
nbytes = ck->len - ck->off;
if (nbytes == 0)
return (0);
memcpy(buf, ck->buf + ck->off, nbytes);
ck->off += nbytes;
return (nbytes);
}
static int
fmemopen_write(void *cookie, const char *buf, int nbytes)
{
struct fmemopen_cookie *ck = cookie;
if (nbytes > ck->size - ck->off)
nbytes = ck->size - ck->off;
if (nbytes == 0)
return (0);
memcpy(ck->buf + ck->off, buf, nbytes);
ck->off += nbytes;
if (ck->off > ck->len)
ck->len = ck->off;
if (!ck->bin && ck->off < ck->size && ck->buf[ck->off - 1] != '\0')
ck->buf[ck->off] = '\0';
return (nbytes);
}
static fpos_t
fmemopen_seek(void *cookie, fpos_t offset, int whence)
{
struct fmemopen_cookie *ck = cookie;
switch (whence) {
case SEEK_SET:
if (offset > ck->size) {
errno = EINVAL;
return (-1);
}
ck->off = offset;
break;
case SEEK_CUR:
if (ck->off + offset > ck->size) {
errno = EINVAL;
return (-1);
}
ck->off += offset;
break;
case SEEK_END:
if (offset > 0 || -offset > ck->len) {
errno = EINVAL;
return (-1);
}
ck->off = ck->len + offset;
break;
default:
errno = EINVAL;
return (-1);
}
return (ck->off);
}
static int
fmemopen_close(void *cookie)
{
struct fmemopen_cookie *ck = cookie;
if (ck->own)
free(ck->buf);
free(ck);
return (0);
}