1 | filesys.c -- file system support functions
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2 | Version 11 -- 1987-06-03 -- D.N. Lynx Crowe
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3 |
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4 | These functions support a {MS,GEM}DOS-like file system.
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5 | Subdirectories are not supported in this version.
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6 |
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7 | Variables:
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8 | ----------
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9 |
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10 | struct bpb *_thebpb;
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11 | struct dirent _thedir[MAXDIRNT];
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12 | struct dirent *_dptr;
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13 |
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14 | short _thefat[MAXFAT * WDPSEC];
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15 |
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16 | int _fatin, _dirin, _bpbin;
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17 | long _berrno;
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18 |
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19 | Functions:
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20 | ----------
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21 |
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22 | ClusMap(fcp)
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23 | SnapFCB(fcp)
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24 |
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25 | _cl2lsn(bpp, clnum)
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26 | _deadio(fcp)
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27 | _dsrch(de)
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28 | _fmake(fcp)
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29 | _fsize(fcp)
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30 | _ftrnc(dp)
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31 | _getfat(bufad, bpp, nfat)
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32 | _gtcl12(fat, cl)
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33 | _inifcb(fcp, name,ext, mode)
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34 | _nsic(fcp, bpp, fp)
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35 | _opfcb(fcp)
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36 | _ptcl12(fat, cl, val)
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37 | _rdfat(bufad, bpp)
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38 | _rdroot(buf, bpp)
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39 | _rdsec(fcp, buf, ns)
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40 | _seek(fcp)
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41 | _sksec(fcp, sec)
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42 | |
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43 |
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44 | _cl2lsn(bpp, clnum)
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45 |
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46 | Returns the logical sector number for cluster 'clnum' using the BPB
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47 | pointed to by 'bpp'.
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48 |
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49 | int
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50 | _cl2lsn(bpp, clnum)
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51 | struct bpb *bpp;
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52 | int clnum;
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53 |
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54 |
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55 | _ptcl12(fat, cl, val)
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56 |
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57 | Puts 'val' into cluster 'cl' in the FAT at 'fat'.
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58 |
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59 | putlc12(fat, cl, val)
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60 | register char *fat;
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61 | int cl, val;
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62 |
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63 | _gtcl12(fat, cl)
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64 |
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65 | Returns the 12 bit cluster entry 'cl' from the FAT pointed to by 'fat'.
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66 |
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67 | int
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68 | _gtcl12(fat, cl)
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69 | register char *fat;
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70 | int cl;
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71 | |
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72 |
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73 | _getfat(bufad, bpp, nfat)
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74 |
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75 | Gets the FAT 'nfat' into the buffer pointed to by 'bufad' using
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76 | the BPB pointed to by 'bpp'.
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77 |
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78 | int
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79 | _getfat(bufad, bpp, nfat)
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80 | int *bufad, nfat;
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81 | register struct bpb *bpp;
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82 |
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83 | _rdfat(bufad, bpp)
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84 |
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85 | Reads the FAT into the buffer pointed to by 'bufad'using the BPB
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86 | pointed to by 'bpp'.
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87 |
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88 | int
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89 | _rdfat(bufad, bpp)
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90 | int *bufad;
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91 | struct bpb *bpp;
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92 |
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93 | _rdroot(buf, bpp)
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94 |
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95 | Reads the root directory into the buffer pointed to by 'buf'
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96 | using the BPB pointed to by 'bpp'.
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97 |
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98 | int
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99 | _rdroot(buf, bpp)
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100 | int *buf;
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101 | register struct bpb *bpp;
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102 |
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103 | _nsic(fcp, bpp, fp)
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104 |
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105 | Gets the next sector in the file controlled by the FCB at 'fcp',
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106 | using the BPB pointed to by 'bpp' and the FAT pointed to by 'fp'.
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107 | Returns: 0 if successful, -1 on error, or 1 on EOF;
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108 |
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109 | int
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110 | _nsic(fcp, bpp, fp)
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111 | register struct fcb *fcp;
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112 | struct bpb *bpp;
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113 | char *fp;
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114 |
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115 | _dsrch(de)
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116 |
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117 | Searches for the directory entry pointed to by 'de' in
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118 | the current directory.
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119 |
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120 | struct dirent *
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121 | _dsrch(de)
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122 | register struct dirent *de;
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123 | |
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124 |
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125 | _deadio(fcp)
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126 |
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127 | Marks the FCB pointed to by 'fcp' as 'in error'.
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128 |
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129 | _deadio(fcp)
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130 | register struct fcb *fcp;
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131 |
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132 | _seek(fcp)
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133 |
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134 | Seeks to to logical sector number in FCB pointed to by 'fcp'
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135 | Returns: -1 = error, 0 = OK, 1 = EOF.
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136 |
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137 | int
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138 | _seek(fcp)
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139 | register struct fcb *fcp;
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140 |
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141 | _ftrnc(dp)
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142 |
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143 | Truncates the file pointed to by directory entry 'dp'.
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144 |
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145 | int
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146 | _ftrnc(dp)
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147 | struct dirent *dp;
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148 |
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149 | _fmake(fcp)
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150 |
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151 | Makes a new file from the FCB pointed to by 'fcp'.
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152 |
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153 | int
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154 | _fmake(fcp)
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155 | struct fcb *fcp;
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156 |
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157 | _opfcb(fcp)
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158 |
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159 | Opens the FCB pointed to by 'fcp'. Returns 0 if opened successfully,
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160 | -1 if an error occurred, with the error code in errno.
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161 |
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162 | int
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163 | _opfcb(fcp)
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164 | register struct fcb *fcp;
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165 |
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166 | _inifcb(fcp, name,ext, mode)
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167 |
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168 | Initializes the FCB pointed to by 'fcp' for the file named 'name'.'ext'
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169 | in mode 'mode'. Returns 0 if ok, -1 if not.
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170 |
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171 | int
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172 | _inifcb(fcp, name, ext, mode)
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173 | register struct fcb *fcp;
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174 | char *name, *ext;
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175 | int mode;
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176 | |
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177 |
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178 | _sksec(fcp, sec)
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179 |
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180 | Seeks the FCB pointed to by 'fcp' to sector 'sec'.
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181 | Returns: -1 = error, 0 = OK, 1 = EOF
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182 |
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183 | int
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184 | _sksec(fcp, sec)
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185 | struct fcb *fcp;
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186 | long sec;
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187 |
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188 | _fsize(fcp)
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189 |
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190 | Returns the size, in sectors, of the file associated with
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191 | the FCB pointed to by 'fcp', or -1 if the FCB isn't open.
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192 |
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193 | int
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194 | _fsize(fcp)
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195 | struct fcb *fcp;
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196 |
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197 | _rdsec(fcp, buf, ns)
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198 |
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199 | Reads 'ns' sectors into the buffer at 'buf' from the file associated
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200 | with the FCB pointed to b 'fcp'. Returns 0 if OK, -1 if not.
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201 |
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202 | int
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203 | _rdsec(fcp, buf, ns)
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204 | struct fcb *fcp;
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205 | char *buf;
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206 | long ns;
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207 |
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208 | ClusMap(fcp)
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209 |
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210 | Prints a map of the clusters for the file associated with
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211 | the FCB pointed to by 'fcp'. Ignored if file isn't open.
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212 | Returns 0 if map was printed, -1 otherwise.
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213 |
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214 | int
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215 | ClusMap(fcp)
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216 | struct fcb *fcp;
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217 |
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218 | SnapFCB(fcp)
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219 |
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220 | Prints the contents of an FCB pointed to by 'fcp'. Only included
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221 | in test versions of 'filesys.c' where TESTER is defined non-zero.
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222 |
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223 | SnapFCB(fcp)
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224 | struct fcb *fcp;
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