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#include "stdio_impl.h"
#include <wchar.h>
#include <errno.h>
#include <limits.h>
#include <string.h>
struct cookie {
wchar_t **bufp;
size_t *sizep;
size_t pos;
wchar_t *buf;
size_t len;
size_t space;
mbstate_t mbs;
};
static off_t wms_seek(FILE *f, off_t off, int whence)
{
ssize_t base;
struct cookie *c = f->cookie;
if (whence>2U) {
fail:
errno = EINVAL;
return -1;
}
base = (size_t [3]){0, c->pos, c->len}[whence];
if (off < -base || off > SSIZE_MAX/4-base) goto fail;
memset(&c->mbs, 0, sizeof c->mbs);
return c->pos = base+off;
}
static size_t wms_write(FILE *f, const unsigned char *buf, size_t len)
{
struct cookie *c = f->cookie;
size_t len2;
wchar_t *newbuf;
if (len + c->pos >= c->space) {
len2 = 2*c->space+1 | c->pos+len+1;
if (len2 > SSIZE_MAX/4) return 0;
newbuf = realloc(c->buf, len2*4);
if (!newbuf) return 0;
*c->bufp = c->buf = newbuf;
memset(c->buf + c->space, 0, 4*(len2 - c->space));
c->space = len2;
}
len2 = mbsnrtowcs(c->buf+c->pos, (void *)&buf, len, c->space-c->pos, &c->mbs);
if (len2 == -1) return 0;
c->pos += len2;
if (c->pos >= c->len) c->len = c->pos;
*c->sizep = c->pos;
return len;
}
static int wms_close(FILE *f)
{
return 0;
}
FILE *open_wmemstream(wchar_t **bufp, size_t *sizep)
{
FILE *f;
struct cookie *c;
wchar_t *buf;
if (!(f=malloc(sizeof *f + sizeof *c))) return 0;
if (!(buf=malloc(sizeof *buf))) {
free(f);
return 0;
}
memset(f, 0, sizeof *f + sizeof *c);
f->cookie = c = (void *)(f+1);
c->bufp = bufp;
c->sizep = sizep;
c->pos = c->len = c->space = *sizep = 0;
c->buf = *bufp = buf;
*buf = 0;
f->flags = F_NORD;
f->fd = -1;
f->buf = (void *)(c+1);
f->buf_size = 0;
f->lbf = EOF;
f->write = wms_write;
f->seek = wms_seek;
f->close = wms_close;
if (!libc.threaded) f->lock = -1;
return __ofl_add(f);
}
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