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