1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
|
/*
* Copyright (c) 1990 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that the above copyright notice and this paragraph are
* duplicated in all such forms and that any documentation,
* advertising materials, and other materials related to such
* distribution and use acknowledge that the software was developed
* by the University of California, Berkeley. The name of the
* University may not be used to endorse or promote products derived
* from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "%W% (Berkeley) %G%";
#endif /* LIBC_SCCS and not lint */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "local.h"
/*
* Expand the ungetc buffer `in place'. That is, adjust fp->_p when
* the buffer moves, so that it points the same distance from the end,
* and move the bytes in the buffer around as necessary so that they
* are all at the end (stack-style).
*/
/*static*/
int
__submore (fp)
register FILE *fp;
{
register int i;
register unsigned char *p;
if (fp->_ub._base == fp->_ubuf)
{
/*
* Get a new buffer (rather than expanding the old one).
*/
if ((p = (unsigned char *) _malloc_r (fp->_data, (size_t) BUFSIZ)) == NULL)
return EOF;
fp->_ub._base = p;
fp->_ub._size = BUFSIZ;
p += BUFSIZ - sizeof (fp->_ubuf);
for (i = sizeof (fp->_ubuf); --i >= 0;)
p[i] = fp->_ubuf[i];
fp->_p = p;
return 0;
}
i = fp->_ub._size;
p = (unsigned char *) _realloc_r (fp->_data, (_PTR) (fp->_ub._base), i << 1);
if (p == NULL)
return EOF;
(void) memcpy ((void *) (p + i), (void *) p, (size_t) i);
fp->_p = p + i;
fp->_ub._base = p;
fp->_ub._size = i << 1;
return 0;
}
int
ungetc (c, fp)
int c;
register FILE *fp;
{
if (c == EOF)
return (EOF);
_flockfile(fp);
/* Ensure stdio has been initialized.
??? Might be able to remove this as some other stdio routine should
have already been called to get the char we are un-getting. */
CHECK_INIT (fp);
/* After ungetc, we won't be at eof anymore */
fp->_flags &= ~__SEOF;
if ((fp->_flags & __SRD) == 0)
{
/*
* Not already reading: no good unless reading-and-writing.
* Otherwise, flush any current write stuff.
*/
if ((fp->_flags & __SRW) == 0)
{
_funlockfile(fp);
return EOF;
}
if (fp->_flags & __SWR)
{
if (fflush (fp))
{
_funlockfile(fp);
return EOF;
}
fp->_flags &= ~__SWR;
fp->_w = 0;
fp->_lbfsize = 0;
}
fp->_flags |= __SRD;
}
c = (unsigned char) c;
/*
* If we are in the middle of ungetc'ing, just continue.
* This may require expanding the current ungetc buffer.
*/
if (HASUB (fp))
{
if (fp->_r >= fp->_ub._size && __submore (fp))
{
_funlockfile(fp);
return EOF;
}
*--fp->_p = c;
fp->_r++;
_funlockfile(fp);
return c;
}
/*
* If we can handle this by simply backing up, do so,
* but never replace the original character.
* (This makes sscanf() work when scanning `const' data.)
*/
if (fp->_bf._base != NULL && fp->_p > fp->_bf._base && fp->_p[-1] == c)
{
fp->_p--;
fp->_r++;
_funlockfile(fp);
return c;
}
/*
* Create an ungetc buffer.
* Initially, we will use the `reserve' buffer.
*/
fp->_ur = fp->_r;
fp->_up = fp->_p;
fp->_ub._base = fp->_ubuf;
fp->_ub._size = sizeof (fp->_ubuf);
fp->_ubuf[sizeof (fp->_ubuf) - 1] = c;
fp->_p = &fp->_ubuf[sizeof (fp->_ubuf) - 1];
fp->_r = 1;
_funlockfile(fp);
return c;
}
|
