github.com/afumu/libc@v0.0.6/musl/src/stdio/open_wmemstream.c (about)

     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  }