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3756 | svoboda | 1 | /* |
2 | * Copyright (c) 2008 Jiri Svoboda |
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3 | * All rights reserved. |
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4 | * |
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5 | * Redistribution and use in source and binary forms, with or without |
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6 | * modification, are permitted provided that the following conditions |
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7 | * are met: |
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8 | * |
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9 | * - Redistributions of source code must retain the above copyright |
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10 | * notice, this list of conditions and the following disclaimer. |
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11 | * - Redistributions in binary form must reproduce the above copyright |
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12 | * notice, this list of conditions and the following disclaimer in the |
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13 | * documentation and/or other materials provided with the distribution. |
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14 | * - The name of the author may not be used to endorse or promote products |
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15 | * derived from this software without specific prior written permission. |
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16 | * |
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17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
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21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
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26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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27 | */ |
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28 | |||
29 | /** @addtogroup libc |
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30 | * @{ |
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31 | */ |
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32 | /** |
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33 | * @file |
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34 | * @brief ANSI C Stream I/O. |
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35 | */ |
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36 | |||
37 | #include <stdlib.h> |
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38 | #include <sys/types.h> |
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39 | #include <sys/stat.h> |
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40 | #include <fcntl.h> |
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41 | #include <unistd.h> |
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42 | #include <errno.h> |
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43 | #include <bool.h> |
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44 | #include <stdio.h> |
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45 | |||
46 | /** |
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47 | * Open a stream. |
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48 | * |
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49 | * @param file_name Name of the file to open. |
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50 | * @param mode Mode string, (r|w|a)[b|t][+]. |
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51 | */ |
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52 | FILE *fopen(const char *file_name, const char *mode) |
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53 | { |
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54 | FILE *f; |
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55 | int flags; |
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56 | bool plus; |
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57 | const char *mp; |
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58 | |||
59 | /* Parse mode except first character. */ |
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60 | |||
61 | mp = mode; |
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62 | if (*mp++ == '\0') { |
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63 | errno = EINVAL; |
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64 | return NULL; |
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65 | } |
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66 | |||
67 | if (*mp == 'b' || *mp == 't') ++mp; |
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68 | |||
69 | if (*mp == '+') { |
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70 | ++mp; |
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71 | plus = true; |
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72 | } else { |
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73 | plus = false; |
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74 | } |
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75 | |||
76 | if (*mp != '\0') { |
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77 | errno = EINVAL; |
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78 | return NULL; |
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79 | } |
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80 | |||
81 | /* Parse first character of mode and determine flags for open(). */ |
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82 | |||
83 | switch (mode[0]) { |
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84 | case 'r': |
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85 | flags = plus ? O_RDWR : O_RDONLY; |
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86 | break; |
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87 | case 'w': |
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88 | flags = (O_TRUNC | O_CREAT) | (plus ? O_RDWR : O_WRONLY); |
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89 | break; |
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90 | case 'a': |
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91 | /* TODO: a+ must read from beginning, append to the end. */ |
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92 | if (plus) { |
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93 | errno = ENOTSUP; |
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94 | return NULL; |
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95 | } |
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96 | flags = (O_APPEND | O_CREAT) | (plus ? O_RDWR : O_WRONLY); |
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97 | default: |
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98 | errno = EINVAL; |
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99 | return NULL; |
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100 | } |
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101 | |||
102 | /* Open file. */ |
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103 | |||
104 | f = malloc(sizeof(FILE)); |
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105 | if (f == NULL) { |
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106 | errno = ENOMEM; |
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107 | return NULL; |
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108 | } |
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109 | |||
110 | f->fd = open(file_name, flags, 0666); |
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111 | if (f->fd < 0) { |
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112 | free(f); |
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113 | return NULL; /* errno was set by open() */ |
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114 | } |
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115 | |||
116 | f->error = 0; |
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117 | f->eof = 0; |
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118 | |||
119 | return f; |
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120 | } |
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121 | |||
122 | /** Close a stream. |
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123 | * |
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124 | * @param f Pointer to stream. |
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125 | * @return 0 on success, EOF on error. |
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126 | */ |
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127 | int fclose(FILE *f) |
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128 | { |
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129 | int rc; |
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130 | |||
131 | rc = close(f->fd); |
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132 | free(f); |
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133 | |||
134 | if (rc != 0) |
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135 | return EOF; /* errno was set by close() */ |
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136 | |||
137 | return 0; |
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138 | } |
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139 | |||
140 | /** Read from a stream. |
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141 | * |
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142 | * @param buf Destination buffer. |
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143 | * @param size Size of each record. |
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144 | * @param nmemb Number of records to read. |
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145 | * @param f Pointer to the stream. |
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146 | */ |
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147 | size_t fread(void *buf, size_t size, size_t nmemb, FILE *f) |
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148 | { |
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149 | size_t left, done, n; |
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150 | |||
151 | left = size * nmemb; |
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152 | done = 0; |
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153 | |||
154 | while (left > 0 && !f->error && !f->eof) { |
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155 | n = read(f->fd, buf + done, left); |
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156 | |||
157 | if (n < 0) { |
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158 | f->error = 1; |
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159 | } else if (n == 0) { |
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160 | f->eof = 1; |
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161 | } else { |
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162 | left -= n; |
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163 | done += n; |
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164 | } |
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165 | } |
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166 | |||
167 | return done / size; |
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168 | } |
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169 | |||
170 | |||
171 | /** Write to a stream. |
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172 | * |
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173 | * @param buf Source buffer. |
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174 | * @param size Size of each record. |
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175 | * @param nmemb Number of records to write. |
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176 | * @param f Pointer to the stream. |
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177 | */ |
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178 | size_t fwrite(const void *buf, size_t size, size_t nmemb, FILE *f) |
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179 | { |
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180 | size_t left, done, n; |
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181 | |||
182 | left = size * nmemb; |
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183 | done = 0; |
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184 | |||
185 | while (left > 0 && !f->error) { |
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186 | n = write(f->fd, buf + done, left); |
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187 | |||
188 | if (n <= 0) { |
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189 | f->error = 1; |
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190 | } else { |
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191 | left -= n; |
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192 | done += n; |
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193 | } |
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194 | } |
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195 | |||
196 | return done / size; |
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197 | } |
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198 | |||
199 | /** Return the end-of-file indicator of a stream. */ |
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200 | int feof(FILE *f) |
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201 | { |
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202 | return f->eof; |
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203 | } |
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204 | |||
205 | /** Return the error indicator of a stream. */ |
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206 | int ferror(FILE *f) |
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207 | { |
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208 | return f->error; |
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209 | } |
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210 | |||
211 | /** Clear the error and end-of-file indicators of a stream. */ |
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212 | void clearerr(FILE *f) |
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213 | { |
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214 | f->eof = 0; |
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215 | f->error = 0; |
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216 | } |
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217 | |||
218 | /** @} |
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219 | */ |