1 | /* Boost.MultiIndex example of composite keys. |
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2 | * |
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3 | * Copyright 2003-2005 Joaquín M López Muñoz. |
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4 | * Distributed under the Boost Software License, Version 1.0. |
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5 | * (See accompanying file LICENSE_1_0.txt or copy at |
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6 | * http://www.boost.org/LICENSE_1_0.txt) |
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7 | * |
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8 | * See http://www.boost.org/libs/multi_index for library home page. |
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9 | */ |
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10 | |
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11 | #if !defined(NDEBUG) |
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12 | #define BOOST_MULTI_INDEX_ENABLE_INVARIANT_CHECKING |
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13 | #define BOOST_MULTI_INDEX_ENABLE_SAFE_MODE |
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14 | #endif |
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15 | |
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16 | #include <boost/call_traits.hpp> |
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17 | #include <boost/multi_index_container.hpp> |
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18 | #include <boost/multi_index/composite_key.hpp> |
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19 | #include <boost/multi_index/member.hpp> |
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20 | #include <boost/multi_index/ordered_index.hpp> |
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21 | #include <boost/tokenizer.hpp> |
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22 | #include <functional> |
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23 | #include <iostream> |
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24 | #include <iterator> |
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25 | #include <map> |
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26 | #include <string> |
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27 | |
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28 | using namespace boost::multi_index; |
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29 | |
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30 | /* A file record maintains some info on name and size as well |
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31 | * as a pointer to the directory it belongs (null meaning the root |
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32 | * directory.) |
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33 | */ |
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34 | |
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35 | struct file_entry |
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36 | { |
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37 | file_entry( |
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38 | std::string name_,unsigned size_,bool is_dir_,const file_entry* dir_): |
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39 | name(name_),size(size_),is_dir(is_dir_),dir(dir_) |
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40 | {} |
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41 | |
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42 | std::string name; |
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43 | unsigned size; |
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44 | bool is_dir; |
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45 | const file_entry* dir; |
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46 | |
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47 | friend std::ostream& operator<<(std::ostream& os,const file_entry& f) |
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48 | { |
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49 | os<<f.name<<"\t"<<f.size; |
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50 | if(f.is_dir)os<<"\t <dir>"; |
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51 | return os; |
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52 | } |
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53 | }; |
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54 | |
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55 | /* A file system is just a multi_index_container of entries with indices on |
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56 | * file and size. These indices are firstly ordered by directory, as commands |
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57 | * work on a current directory basis. Composite keys are just fine to model |
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58 | * this. |
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59 | * NB: The use of derivation here instead of simple typedef is explained in |
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60 | * Compiler specifics: type hiding. |
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61 | */ |
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62 | |
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63 | struct name_key:composite_key< |
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64 | file_entry, |
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65 | BOOST_MULTI_INDEX_MEMBER(file_entry,const file_entry*,dir), |
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66 | BOOST_MULTI_INDEX_MEMBER(file_entry,std::string,name) |
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67 | >{}; |
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68 | |
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69 | struct size_key:composite_key< |
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70 | file_entry, |
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71 | BOOST_MULTI_INDEX_MEMBER(file_entry,const file_entry* const,dir), |
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72 | BOOST_MULTI_INDEX_MEMBER(file_entry,unsigned,size) |
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73 | >{}; |
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74 | |
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75 | /* see Compiler specifics: composite_key in compilers without partial |
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76 | * template specialization, for info on composite_key_result_less |
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77 | */ |
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78 | |
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79 | typedef multi_index_container< |
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80 | file_entry, |
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81 | indexed_by< |
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82 | /* primary index sorted by name (inside the same directory) */ |
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83 | ordered_unique< |
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84 | name_key |
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85 | #if defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) |
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86 | ,composite_key_result_less<name_key::result_type> |
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87 | #endif |
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88 | >, |
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89 | /* secondary index sorted by size (inside the same directory) */ |
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90 | ordered_non_unique< |
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91 | size_key |
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92 | #if defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) |
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93 | ,composite_key_result_less<size_key::result_type> |
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94 | #endif |
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95 | > |
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96 | > |
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97 | > file_system; |
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98 | |
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99 | /* typedef's of the two indices of file_system */ |
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100 | |
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101 | typedef nth_index<file_system,0>::type file_system_by_name; |
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102 | typedef nth_index<file_system,1>::type file_system_by_size; |
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103 | |
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104 | /* We build a rudimentary file system simulation out of some global |
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105 | * info and a map of commands provided to the user. |
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106 | */ |
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107 | |
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108 | static file_system fs; /* the one and only file system */ |
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109 | static file_system_by_name& fs_by_name=fs; /* name index to fs */ |
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110 | static file_system_by_size& fs_by_size=get<1>(fs); /* size index to fs */ |
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111 | static const file_entry* current_dir=0; /* root directory */ |
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112 | |
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113 | /* command framework */ |
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114 | |
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115 | /* A command provides an execute memfun fed with the corresponding params |
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116 | * (first param is stripped off as it serves to identify the command |
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117 | * currently being used.) |
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118 | */ |
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119 | |
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120 | typedef boost::tokenizer<boost::char_separator<char> > command_tokenizer; |
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121 | |
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122 | class command |
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123 | { |
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124 | public: |
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125 | virtual ~command(){} |
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126 | virtual void execute( |
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127 | command_tokenizer::iterator tok1,command_tokenizer::iterator tok2)=0; |
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128 | }; |
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129 | |
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130 | /* available commands */ |
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131 | |
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132 | /* cd: syntax cd [.|..|<directory>] */ |
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133 | |
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134 | class command_cd:public command |
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135 | { |
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136 | public: |
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137 | virtual void execute( |
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138 | command_tokenizer::iterator tok1,command_tokenizer::iterator tok2) |
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139 | { |
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140 | if(tok1==tok2)return; |
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141 | std::string dir=*tok1++; |
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142 | |
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143 | if(dir==".")return; |
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144 | if(dir==".."){ |
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145 | if(current_dir)current_dir=current_dir->dir; |
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146 | return; |
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147 | } |
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148 | |
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149 | file_system_by_name::iterator it=fs.find( |
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150 | boost::make_tuple(current_dir,dir)); |
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151 | if(it==fs.end()){ |
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152 | std::cout<<"non-existent directory"<<std::endl; |
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153 | return; |
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154 | } |
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155 | if(!it->is_dir){ |
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156 | std::cout<<dir<<" is not a directory"<<std::endl; |
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157 | return; |
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158 | } |
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159 | current_dir=&*it; |
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160 | } |
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161 | }; |
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162 | static command_cd cd; |
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163 | |
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164 | /* ls: syntax ls [-s] */ |
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165 | |
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166 | class command_ls:public command |
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167 | { |
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168 | public: |
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169 | virtual void execute( |
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170 | command_tokenizer::iterator tok1,command_tokenizer::iterator tok2) |
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171 | { |
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172 | std::string option; |
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173 | if(tok1!=tok2)option=*tok1++; |
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174 | |
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175 | if(!option.empty()){ |
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176 | if(option!="-s"){ |
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177 | std::cout<<"incorrect parameter"<<std::endl; |
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178 | return; |
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179 | } |
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180 | |
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181 | /* list by size */ |
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182 | |
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183 | file_system_by_size::iterator it0,it1; |
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184 | boost::tie(it0,it1)=fs_by_size.equal_range( |
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185 | boost::make_tuple(current_dir)); |
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186 | std::copy(it0,it1,std::ostream_iterator<file_entry>(std::cout,"\n")); |
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187 | |
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188 | return; |
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189 | } |
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190 | |
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191 | /* list by name */ |
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192 | |
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193 | file_system_by_name::iterator it0,it1; |
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194 | boost::tie(it0,it1)=fs.equal_range(boost::make_tuple(current_dir)); |
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195 | std::copy(it0,it1,std::ostream_iterator<file_entry>(std::cout,"\n")); |
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196 | } |
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197 | }; |
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198 | static command_ls ls; |
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199 | |
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200 | /* mkdir: syntax mkdir <directory> */ |
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201 | |
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202 | class command_mkdir:public command |
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203 | { |
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204 | public: |
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205 | virtual void execute( |
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206 | command_tokenizer::iterator tok1,command_tokenizer::iterator tok2) |
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207 | { |
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208 | std::string dir; |
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209 | if(tok1!=tok2)dir=*tok1++; |
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210 | |
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211 | if(dir.empty()){ |
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212 | std::cout<<"missing parameter"<<std::endl; |
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213 | return; |
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214 | } |
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215 | |
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216 | if(dir=="."||dir==".."){ |
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217 | std::cout<<"incorrect parameter"<<std::endl; |
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218 | return; |
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219 | } |
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220 | |
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221 | if(!fs.insert(file_entry(dir,0,true,current_dir)).second){ |
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222 | std::cout<<"directory already exists"<<std::endl; |
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223 | return; |
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224 | } |
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225 | } |
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226 | }; |
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227 | static command_mkdir mkdir; |
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228 | |
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229 | /* table of commands, a map from command names to class command pointers */ |
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230 | |
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231 | typedef std::map<std::string,command*> command_table; |
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232 | static command_table cmt; |
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233 | |
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234 | int main() |
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235 | { |
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236 | /* fill the file system with some data */ |
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237 | |
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238 | file_system::iterator it0,it1; |
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239 | |
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240 | fs.insert(file_entry("usr.cfg",240,false,0)); |
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241 | fs.insert(file_entry("memo.txt",2430,false,0)); |
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242 | it0=fs.insert(file_entry("dev",0,true,0)).first; |
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243 | fs.insert(file_entry("tty0",128,false,&*it0)); |
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244 | fs.insert(file_entry("tty1",128,false,&*it0)); |
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245 | it0=fs.insert(file_entry("usr",0,true,0)).first; |
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246 | it1=fs.insert(file_entry("bin",0,true,&*it0)).first; |
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247 | fs.insert(file_entry("bjam",172032,false,&*it1)); |
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248 | it0=fs.insert(file_entry("home",0,true,0)).first; |
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249 | it1=fs.insert(file_entry("andy",0,true,&*it0)).first; |
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250 | fs.insert(file_entry("logo.jpg",5345,false,&*it1)).first; |
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251 | fs.insert(file_entry("foo.cpp",890,false,&*it1)).first; |
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252 | fs.insert(file_entry("foo.hpp",93,false,&*it1)).first; |
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253 | fs.insert(file_entry("foo.html",750,false,&*it1)).first; |
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254 | fs.insert(file_entry("a.obj",12302,false,&*it1)).first; |
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255 | fs.insert(file_entry(".bash_history",8780,false,&*it1)).first; |
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256 | it1=fs.insert(file_entry("rachel",0,true,&*it0)).first; |
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257 | fs.insert(file_entry("test.py",650,false,&*it1)).first; |
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258 | fs.insert(file_entry("todo.txt",241,false,&*it1)).first; |
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259 | fs.insert(file_entry(".bash_history",9510,false,&*it1)).first; |
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260 | |
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261 | /* fill the command table */ |
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262 | |
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263 | cmt["cd"] =&cd; |
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264 | cmt["ls"] =&ls; |
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265 | cmt["mkdir"]=&mkdir; |
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266 | |
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267 | /* main looop */ |
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268 | |
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269 | for(;;){ |
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270 | /* print out the current directory and the prompt symbol */ |
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271 | |
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272 | if(current_dir)std::cout<<current_dir->name; |
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273 | std::cout<<">"; |
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274 | |
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275 | /* get an input line from the user: if empty, exit the program */ |
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276 | |
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277 | std::string com; |
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278 | std::getline(std::cin,com); |
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279 | command_tokenizer tok(com,boost::char_separator<char>(" \t\n")); |
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280 | if(tok.begin()==tok.end())break; /* null command, exit */ |
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281 | |
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282 | /* select the corresponding command and execute it */ |
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283 | |
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284 | command_table::iterator it=cmt.find(*tok.begin()); |
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285 | if(it==cmt.end()){ |
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286 | std::cout<<"invalid command"<<std::endl; |
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287 | continue; |
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288 | } |
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289 | |
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290 | it->second->execute(++tok.begin(),tok.end()); |
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291 | } |
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292 | |
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293 | return 0; |
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294 | } |
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