src/stdio/open_wmemstream.c

   1 #include "stdio_impl.h"
   2 #include <wchar.h>
   3 #include <errno.h>
   4 #include <limits.h>
   5 #include <string.h>
   6 #include <stdlib.h>
   7 #include "libc.h"
   8
   9 struct cookie {
  10         wchar_t **bufp;
  11         size_t *sizep;
  12         size_t pos;
  13         wchar_t *buf;
  14         size_t len;
  15         size_t space;
  16         mbstate_t mbs;
  17 };
  18
  19 struct wms_FILE {
  20         FILE f;
  21         struct cookie c;
  22         unsigned char buf[1];
  23 };
  24
  25 static off_t wms_seek(FILE *f, off_t off, int whence)
  26 {
  27         ssize_t base;
  28         struct cookie *c = f->cookie;
  29         if (whence>2U) {
  30 fail:
  31                 errno = EINVAL;
  32                 return -1;
  33         }
  34         base = (size_t [3]){0, c->pos, c->len}[whence];
  35         if (off < -base || off > SSIZE_MAX/4-base) goto fail;
  36         memset(&c->mbs, 0, sizeof c->mbs);
  37         return c->pos = base+off;
  38 }
  39
  40 static size_t wms_write(FILE *f, const unsigned char *buf, size_t len)
  41 {
  42         struct cookie *c = f->cookie;
  43         size_t len2 = f->wpos - f->wbase;
  44         wchar_t *newbuf;
  45         if (len2) {
  46                 f->wpos = f->wbase;
  47                 if (wms_write(f, f->wbase, len2) < len2) return 0;
  48         }
  49         if (len + c->pos >= c->space) {
  50                 len2 = 2*c->space+1 | c->pos+len+1;
  51                 if (len2 > SSIZE_MAX/4) return 0;
  52                 newbuf = realloc(c->buf, len2*4);
  53                 if (!newbuf) return 0;
  54                 *c->bufp = c->buf = newbuf;
  55                 memset(c->buf + c->space, 0, 4*(len2 - c->space));
  56                 c->space = len2;
  57         }
  58
  59         len2 = mbsnrtowcs(c->buf+c->pos, (void *)&buf, len, c->space-c->pos, &c->mbs);
  60         if (len2 == -1) return 0;
  61         c->pos += len2;
  62         if (c->pos >= c->len) c->len = c->pos;
  63         *c->sizep = c->pos;
  64         return len;
  65 }
  66
  67 static int wms_close(FILE *f)
  68 {
  69         return 0;
  70 }
  71
  72 FILE *open_wmemstream(wchar_t **bufp, size_t *sizep)
  73 {
  74         struct wms_FILE *f;
  75         wchar_t *buf;
  76
  77         if (!(f=malloc(sizeof *f))) return 0;
  78         if (!(buf=malloc(sizeof *buf))) {
  79                 free(f);
  80                 return 0;
  81         }
  82         memset(&f->f, 0, sizeof f->f);
  83         memset(&f->c, 0, sizeof f->c);
  84         f->f.cookie = &f->c;
  85
  86         f->c.bufp = bufp;
  87         f->c.sizep = sizep;
  88         f->c.pos = f->c.len = f->c.space = *sizep = 0;
  89         f->c.buf = *bufp = buf;
  90         *buf = 0;
  91
  92         f->f.flags = F_NORD;
  93         f->f.fd = -1;
  94         f->f.buf = f->buf;
  95         f->f.buf_size = 0;
  96         f->f.lbf = EOF;
  97         f->f.write = wms_write;
  98         f->f.seek = wms_seek;
  99         f->f.close = wms_close;
 100
 101         if (!libc.threaded) f->f.lock = -1;
 102
 103         fwide(&f->f, 1);
 104
 105         return __ofl_add(&f->f);
 106 }