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1 | /** @file\r | |
2 | Implementation of ungetc as declared in <stdio.h>.\r | |
3 | \r | |
4 | Copyright (c) 2010 - 2011, Intel Corporation. All rights reserved.<BR>\r | |
5 | This program and the accompanying materials are licensed and made available\r | |
6 | under the terms and conditions of the BSD License that accompanies this\r | |
7 | distribution. The full text of the license may be found at\r | |
8 | http://opensource.org/licenses/bsd-license.\r | |
9 | \r | |
10 | THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r | |
11 | WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r | |
12 | \r | |
13 | Copyright (c) 1990, 1993\r | |
14 | The Regents of the University of California. All rights reserved.\r | |
15 | \r | |
16 | This code is derived from software contributed to Berkeley by\r | |
17 | Chris Torek.\r | |
18 | \r | |
19 | Redistribution and use in source and binary forms, with or without\r | |
20 | modification, are permitted provided that the following conditions\r | |
21 | are met:\r | |
22 | - Redistributions of source code must retain the above copyright\r | |
23 | notice, this list of conditions and the following disclaimer.\r | |
24 | - Redistributions in binary form must reproduce the above copyright\r | |
25 | notice, this list of conditions and the following disclaimer in the\r | |
26 | documentation and/or other materials provided with the distribution.\r | |
27 | - Neither the name of the University nor the names of its contributors\r | |
28 | may be used to endorse or promote products derived from this software\r | |
29 | without specific prior written permission.\r | |
30 | \r | |
31 | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"\r | |
32 | AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE\r | |
33 | IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE\r | |
34 | ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE\r | |
35 | LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR\r | |
36 | CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF\r | |
37 | SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS\r | |
38 | INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN\r | |
39 | CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)\r | |
40 | ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE\r | |
41 | POSSIBILITY OF SUCH DAMAGE.\r | |
42 | \r | |
43 | NetBSD: ungetc.c,v 1.14 2003/08/07 16:43:34 agc Exp\r | |
44 | ungetc.c 8.2 (Berkeley) 11/3/93\r | |
45 | **/\r | |
46 | #include <LibConfig.h>\r | |
47 | \r | |
48 | #include <assert.h>\r | |
49 | #include <errno.h>\r | |
50 | #include <stdio.h>\r | |
51 | #include <stdlib.h>\r | |
52 | #include <string.h>\r | |
53 | #include "reentrant.h"\r | |
54 | #include "local.h"\r | |
55 | \r | |
56 | static int __submore(FILE *);\r | |
57 | /*\r | |
58 | * Expand the ungetc buffer `in place'. That is, adjust fp->_p when\r | |
59 | * the buffer moves, so that it points the same distance from the end,\r | |
60 | * and move the bytes in the buffer around as necessary so that they\r | |
61 | * are all at the end (stack-style).\r | |
62 | */\r | |
63 | static int\r | |
64 | __submore(FILE *fp)\r | |
65 | {\r | |
66 | int i;\r | |
67 | unsigned char *p;\r | |
68 | \r | |
69 | _DIAGASSERT(fp != NULL);\r | |
70 | if(fp == NULL) {\r | |
71 | errno = EINVAL;\r | |
72 | return (EOF);\r | |
73 | }\r | |
74 | \r | |
75 | if (_UB(fp)._base == fp->_ubuf) {\r | |
76 | /*\r | |
77 | * Get a new buffer (rather than expanding the old one).\r | |
78 | */\r | |
79 | if ((p = malloc((size_t)BUFSIZ)) == NULL)\r | |
80 | return (EOF);\r | |
81 | _UB(fp)._base = p;\r | |
82 | _UB(fp)._size = BUFSIZ;\r | |
83 | p += BUFSIZ - sizeof(fp->_ubuf);\r | |
84 | for (i = sizeof(fp->_ubuf); --i >= 0;)\r | |
85 | p[i] = fp->_ubuf[i];\r | |
86 | fp->_p = p;\r | |
87 | return (0);\r | |
88 | }\r | |
89 | i = _UB(fp)._size;\r | |
90 | p = realloc(_UB(fp)._base, (size_t)(i << 1));\r | |
91 | if (p == NULL)\r | |
92 | return (EOF);\r | |
93 | /* no overlap (hence can use memcpy) because we doubled the size */\r | |
94 | (void)memcpy((void *)(p + i), (void *)p, (size_t)i);\r | |
95 | fp->_p = p + i;\r | |
96 | _UB(fp)._base = p;\r | |
97 | _UB(fp)._size = i << 1;\r | |
98 | return (0);\r | |
99 | }\r | |
100 | \r | |
101 | int\r | |
102 | ungetc(int c, FILE *fp)\r | |
103 | {\r | |
104 | _DIAGASSERT(fp != NULL);\r | |
105 | if(fp == NULL) {\r | |
106 | errno = EINVAL;\r | |
107 | return (EOF);\r | |
108 | }\r | |
109 | \r | |
110 | if (c == EOF)\r | |
111 | return (EOF);\r | |
112 | if (!__sdidinit)\r | |
113 | __sinit();\r | |
114 | FLOCKFILE(fp);\r | |
115 | _SET_ORIENTATION(fp, -1);\r | |
116 | if ((fp->_flags & __SRD) == 0) {\r | |
117 | /*\r | |
118 | * Not already reading: no good unless reading-and-writing.\r | |
119 | * Otherwise, flush any current write stuff.\r | |
120 | */\r | |
121 | if ((fp->_flags & __SRW) == 0) {\r | |
122 | FUNLOCKFILE(fp);\r | |
123 | return (EOF);\r | |
124 | }\r | |
125 | if (fp->_flags & __SWR) {\r | |
126 | if (__sflush(fp)) {\r | |
127 | FUNLOCKFILE(fp);\r | |
128 | return (EOF);\r | |
129 | }\r | |
130 | fp->_flags &= ~__SWR;\r | |
131 | fp->_w = 0;\r | |
132 | fp->_lbfsize = 0;\r | |
133 | }\r | |
134 | fp->_flags |= __SRD;\r | |
135 | }\r | |
136 | c = (unsigned char)c;\r | |
137 | \r | |
138 | /*\r | |
139 | * If we are in the middle of ungetc'ing, just continue.\r | |
140 | * This may require expanding the current ungetc buffer.\r | |
141 | */\r | |
142 | if (HASUB(fp)) {\r | |
143 | if (fp->_r >= _UB(fp)._size && __submore(fp)) {\r | |
144 | FUNLOCKFILE(fp);\r | |
145 | return (EOF);\r | |
146 | }\r | |
147 | *--fp->_p = (unsigned char)c;\r | |
148 | fp->_r++;\r | |
149 | FUNLOCKFILE(fp);\r | |
150 | return (c);\r | |
151 | }\r | |
152 | fp->_flags &= ~__SEOF;\r | |
153 | \r | |
154 | /*\r | |
155 | * If we can handle this by simply backing up, do so,\r | |
156 | * but never replace the original character.\r | |
157 | * (This makes sscanf() work when scanning `const' data.)\r | |
158 | */\r | |
159 | if (fp->_bf._base != NULL && fp->_p > fp->_bf._base &&\r | |
160 | fp->_p[-1] == c) {\r | |
161 | fp->_p--;\r | |
162 | fp->_r++;\r | |
163 | FUNLOCKFILE(fp);\r | |
164 | return (c);\r | |
165 | }\r | |
166 | \r | |
167 | /*\r | |
168 | * Create an ungetc buffer.\r | |
169 | * Initially, we will use the `reserve' buffer.\r | |
170 | */\r | |
171 | fp->_ur = fp->_r;\r | |
172 | fp->_up = fp->_p;\r | |
173 | _UB(fp)._base = fp->_ubuf;\r | |
174 | _UB(fp)._size = sizeof(fp->_ubuf);\r | |
175 | fp->_ubuf[sizeof(fp->_ubuf) - 1] = (unsigned char)c;\r | |
176 | fp->_p = &fp->_ubuf[sizeof(fp->_ubuf) - 1];\r | |
177 | fp->_r = 1;\r | |
178 | FUNLOCKFILE(fp);\r | |
179 | return (c);\r | |
180 | }\r |