source/path.cpp

   1 /*
   2 This file is part of libmsppath
   3 Copyright © 2006  Mikko Rasa, Mikkosoft Productions
   4 Distributed under the LGPL
   5 */
   6 #include <msp/strutils.h>
   7 #include "path.h"
   8 #include "utils.h"
   9
  10 using namespace std;
  11
  12 namespace Msp {
  13 namespace Path {
  14
  15 /**
  16 Returns the number of components in the path.
  17 */
  18 unsigned Path::size() const
  19 {
  20         if(!path.size()) return 0;
  21         if(path.size()==1 && path[0]==DIRCHAR) return 1;
  22         unsigned count=1;
  23         for(string::const_iterator i=path.begin(); i!=path.end(); ++i)
  24                 if(*i==DIRCHAR) ++count;
  25         return count;
  26 }
  27
  28 bool Path::is_absolute() const
  29 {
  30 #ifdef WIN32
  31         if(is_windows_drive((*this)[0])) return true;
  32 #endif
  33         if(path[0]==DIRCHAR) return true;
  34         return false;
  35 }
  36
  37 /**
  38 Extracts the given component range from the path.
  39 */
  40 Path Path::subpath(unsigned start, unsigned count) const
  41 {
  42         Path result;
  43         iterator i=begin();
  44         for(unsigned j=0; (j<start && i!=end()); ++j)
  45                 ++i;
  46         for(unsigned j=0; (j<count && i!=end()); ++j)
  47         {
  48                 result/=*i;
  49                 ++i;
  50         }
  51         return result;
  52 }
  53
  54 /**
  55 Attaches another path to the end of this one.  An absolute path replaces the
  56 existing data.  ".." elements annihilate the last component and "." elements
  57 are ignored.
  58 */
  59 Path &Path::operator/=(const Path &p)
  60 {
  61         if(p.is_absolute())
  62                 path=p.path;
  63         else
  64         {
  65                 for(iterator i=p.begin(); i!=p.end(); ++i)
  66                         add_component(*i);
  67         }
  68         return *this;
  69 }
  70
  71 /**
  72 Returns the path component at the specified index.  Negative indices count from
  73 the end of the path.
  74 */
  75 string Path::operator[](int n) const
  76 {
  77         if(n>=0)
  78         {
  79                 for(iterator i=begin(); i!=end(); ++i,--n)
  80                         if(!n) return *i;
  81         }
  82         else
  83         {
  84                 for(iterator i=--end();; --i)
  85                 {
  86                         if(!++n) return *i;
  87                         if(i==begin()) break;
  88                 }
  89         }
  90
  91         return "";
  92 }
  93
  94 bool Path::operator==(const Path &p) const
  95 {
  96 #ifdef WIN32
  97         return !strcasecmp(path, p.path);
  98 #else
  99         return path==p.path;
 100 #endif
 101 }
 102
 103 void Path::init(const string &p)
 104 {
 105         unsigned start=0;
 106         if(p[0]=='/' || p[0]=='\\')
 107                 add_component(string(1, DIRCHAR));
 108         while(1)
 109         {
 110                 unsigned slash=p.find_first_of("/\\",start);
 111                 if(slash>start)
 112                 {
 113                         add_component(p.substr(start, slash-start));
 114                 }
 115                 if(slash==string::npos)
 116                         break;
 117                 start=slash+1;
 118         }
 119 }
 120
 121 /**
 122 Adds a single component to the path, emulating the cd command.
 123 */
 124 void Path::add_component(const string &comp)
 125 {
 126         if(comp.empty())
 127                 ;
 128         else if(comp.size()==1 && comp[0]==DIRCHAR)
 129         {
 130                 // Replace the path with the root directory
 131 #ifdef WIN32
 132                 unsigned slash=path.find(DIRCHAR);
 133                 if(is_windows_drive(path.substr(0, slash)))
 134                         path=path.substr(0,2);
 135                 else
 136 #endif
 137                 path=comp;
 138         }
 139 #ifdef WIN32
 140         else if(is_windows_drive(comp))
 141                 path=comp;
 142 #endif
 143         else if(comp=="..")
 144         {
 145                 if(path.empty())
 146                         path=comp;
 147                 // .. in root directory is a no-op
 148                 else if(path.size()==1 && path[0]==DIRCHAR)
 149                         ;
 150 #ifdef WIN32
 151                 else if(is_windows_drive(path))
 152                         ;
 153 #endif
 154                 else
 155                 {
 156                         unsigned slash=path.rfind(DIRCHAR);
 157                         unsigned start=(slash==string::npos)?0:slash+1;
 158                         if(!path.compare(start, string::npos, ".."))
 159                         {
 160                                 // If the last component already is a .., add another
 161                                 path+=DIRCHAR;
 162                                 path+=comp;
 163                         }
 164                         else
 165                                 // Otherwise, erase the last component
 166                                 path.erase(slash, string::npos);
 167                 }
 168         }
 169         else if(comp!=".")
 170         {
 171                 if(path.size()>1 || (path.size()==1 && path[0]!=DIRCHAR))
 172                         path+=DIRCHAR;
 173                 path+=comp;
 174         }
 175 }
 176
 177 Path::iterator::iterator(const Path &p):
 178         path(p),
 179         start(0)
 180 {
 181         if(path.path.empty())
 182                 start=end=string::npos;
 183         else if(path.path[0]==DIRCHAR)
 184                 end=1;
 185 #ifdef WIN32
 186         else if(path.path.size()>2 && path.path[2]==DIRCHAR && is_windows_drive(path.path.substr(0,2)))
 187                 end=2;
 188 #endif
 189         else
 190                 end=path.path.find(DIRCHAR);
 191 }
 192
 193 Path::iterator &Path::iterator::operator++()
 194 {
 195         start=end;
 196         if(start>=path.path.size()) return *this;
 197         if(path.path[start]==DIRCHAR) ++start;
 198         end=path.path.find(DIRCHAR,start);
 199         return *this;
 200 }
 201
 202 Path::iterator &Path::iterator::operator--()
 203 {
 204         end=start;
 205         if(end==0) return *this;
 206         if(end>1 && end<path.path.size() && path.path[end]!=DIRCHAR) --end;
 207         start=path.path.rfind(DIRCHAR,end-1);
 208         if(start==string::npos)
 209                 start=0;
 210         else if(start<end-1)
 211                 ++start;
 212         return *this;
 213 }
 214
 215 string Path::iterator::operator*() const
 216 {
 217         if(start>=path.path.size()) return "";
 218         if(start==end) return "";
 219         return path.path.substr(start,end-start);
 220 }
 221
 222 } // namespace Path
 223 } // namespace Msp