1/*	$OpenBSD: open_wmemstream.c,v 1.8 2015/09/12 16:23:14 guenther Exp $	*/
2
3/*
4 * Copyright (c) 2011 Martin Pieuchot <mpi@openbsd.org>
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19#include <errno.h>
20#include <fcntl.h>
21#include <stdio.h>
22#include <stdint.h>
23#include <stdlib.h>
24#include <string.h>
25#include <wchar.h>
26#include "local.h"
27
28#define	MINIMUM(a, b)	(((a) < (b)) ? (a) : (b))
29
30struct state {
31	wchar_t		 *string;	/* actual stream */
32	wchar_t		**pbuf;		/* point to the stream */
33	size_t		 *psize;	/* point to min(pos, len) */
34	size_t		  pos;		/* current position */
35	size_t		  size;		/* number of allocated wchar_t */
36	size_t		  len;		/* length of the data */
37	mbstate_t	  mbs;		/* conversion state of the stream */
38};
39
40static int
41wmemstream_write(void *v, const char *b, int l)
42{
43	struct state	*st = v;
44	wchar_t		*p;
45	size_t		 nmc, len, end;
46
47	end = (st->pos + l);
48
49	if (end >= st->size) {
50		/* 1.6 is (very) close to the golden ratio. */
51		size_t	sz = st->size * 8 / 5;
52
53		if (sz < end + 1)
54			sz = end + 1;
55		p = reallocarray(st->string, sz, sizeof(wchar_t));
56		if (!p)
57			return (-1);
58		bzero(p + st->size, (sz - st->size) * sizeof(wchar_t));
59		*st->pbuf = st->string = p;
60		st->size = sz;
61	}
62
63	nmc = (st->size - st->pos) * sizeof(wchar_t);
64	len = mbsnrtowcs(st->string + st->pos, &b, nmc, l, &st->mbs);
65	if (len == (size_t)-1)
66		return (-1);
67	st->pos += len;
68
69	if (st->pos > st->len) {
70		st->len = st->pos;
71		st->string[st->len] = L'\0';
72	}
73
74	*st->psize = st->pos;
75
76	return (len);
77}
78
79static fpos_t
80wmemstream_seek(void *v, fpos_t off, int whence)
81{
82	struct state	*st = v;
83	ssize_t		 base = 0;
84
85	switch (whence) {
86	case SEEK_SET:
87		break;
88	case SEEK_CUR:
89		base = st->pos;
90		break;
91	case SEEK_END:
92		base = st->len;
93		break;
94	}
95
96	if (off > (SIZE_MAX / sizeof(wchar_t)) - base || off < -base) {
97		errno = EOVERFLOW;
98		return (-1);
99	}
100
101	/*
102	 * XXX Clearing mbs here invalidates shift state for state-
103	 * dependent encodings, but they are not (yet) supported.
104	 */
105	bzero(&st->mbs, sizeof(st->mbs));
106
107	st->pos = base + off;
108	*st->psize = MINIMUM(st->pos, st->len);
109
110	return (st->pos);
111}
112
113static int
114wmemstream_close(void *v)
115{
116	struct state	*st = v;
117
118	free(st);
119
120	return (0);
121}
122
123FILE *
124open_wmemstream(wchar_t **pbuf, size_t *psize)
125{
126	struct state	*st;
127	FILE		*fp;
128
129	if (pbuf == NULL || psize == NULL) {
130		errno = EINVAL;
131		return (NULL);
132	}
133
134	if ((st = malloc(sizeof(*st))) == NULL)
135		return (NULL);
136
137	if ((fp = __sfp()) == NULL) {
138		free(st);
139		return (NULL);
140	}
141
142	st->size = BUFSIZ * sizeof(wchar_t);
143	if ((st->string = calloc(1, st->size)) == NULL) {
144		free(st);
145		fp->_flags = 0;
146		return (NULL);
147	}
148
149	*st->string = L'\0';
150	st->pos = 0;
151	st->len = 0;
152	st->pbuf = pbuf;
153	st->psize = psize;
154	bzero(&st->mbs, sizeof(st->mbs));
155
156	*pbuf = st->string;
157	*psize = st->len;
158
159	fp->_flags = __SWR;
160	fp->_file = -1;
161	fp->_cookie = st;
162	fp->_read = NULL;
163	fp->_write = wmemstream_write;
164	fp->_seek = wmemstream_seek;
165	fp->_close = wmemstream_close;
166	_SET_ORIENTATION(fp, 1);
167
168	return (fp);
169}
170