nsz Git - musl/blob - src/stdio/open_wmemstream.c

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