open_wmemstream.c raw

   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;
  44  	wchar_t *newbuf;
  45  	if (len + c->pos >= c->space) {
  46  		len2 = 2*c->space+1 | c->pos+len+1;
  47  		if (len2 > SSIZE_MAX/4) return 0;
  48  		newbuf = realloc(c->buf, len2*4);
  49  		if (!newbuf) return 0;
  50  		*c->bufp = c->buf = newbuf;
  51  		memset(c->buf + c->space, 0, 4*(len2 - c->space));
  52  		c->space = len2;
  53  	}
  54  	
  55  	len2 = mbsnrtowcs(c->buf+c->pos, (void *)&buf, len, c->space-c->pos, &c->mbs);
  56  	if (len2 == -1) return 0;
  57  	c->pos += len2;
  58  	if (c->pos >= c->len) c->len = c->pos;
  59  	*c->sizep = c->pos;
  60  	return len;
  61  }
  62  
  63  static int wms_close(FILE *f)
  64  {
  65  	return 0;
  66  }
  67  
  68  FILE *open_wmemstream(wchar_t **bufp, size_t *sizep)
  69  {
  70  	struct wms_FILE *f;
  71  	wchar_t *buf;
  72  
  73  	if (!(f=malloc(sizeof *f))) return 0;
  74  	if (!(buf=malloc(sizeof *buf))) {
  75  		free(f);
  76  		return 0;
  77  	}
  78  	memset(&f->f, 0, sizeof f->f);
  79  	memset(&f->c, 0, sizeof f->c);
  80  	f->f.cookie = &f->c;
  81  
  82  	f->c.bufp = bufp;
  83  	f->c.sizep = sizep;
  84  	f->c.pos = f->c.len = f->c.space = *sizep = 0;
  85  	f->c.buf = *bufp = buf;
  86  	*buf = 0;
  87  
  88  	f->f.flags = F_NORD;
  89  	f->f.fd = -1;
  90  	f->f.buf = f->buf;
  91  	f->f.buf_size = 0;
  92  	f->f.lbf = EOF;
  93  	f->f.write = wms_write;
  94  	f->f.seek = wms_seek;
  95  	f->f.close = wms_close;
  96  
  97  	if (!libc.threaded) f->f.lock = -1;
  98  
  99  	fwide(&f->f, 1);
 100  
 101  	return __ofl_add(&f->f);
 102  }
 103