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// file : butl/path-map -*- C++ -*-
// copyright : Copyright (c) 2014-2016 Code Synthesis Ltd
// license : MIT; see accompanying LICENSE file
#ifndef BUTL_PATH_MAP
#define BUTL_PATH_MAP
#include <algorithm> // min()
#include <butl/path>
#include <butl/prefix-map>
namespace butl
{
// prefix_map for filesystem paths
//
// Important: the paths should be normalized but don't have to be
// canonicalized.
//
// Note that the path's representation of POSIX root ('/') is
// inconsistent in that we have a trailing delimiter at the end of
// the path (its "proper" representation would have been an empty
// string but that would have clashed with empty paths). To work
// around this snag, this implementation, during key comparison,
// detects '/' and treats it as empty. Note that the map will
// still store the key as you have first inserted it. So if you
// want a particular representation (i.e., empty or '/'), pre-
// populate the map with it.
//
template <typename C, typename K>
struct compare_prefix<basic_path<C, K>>
{
typedef basic_path<C, K> key_type;
typedef C delimiter_type;
typedef typename key_type::string_type string_type;
typedef typename key_type::size_type size_type;
typedef typename key_type::traits traits_type;
explicit
compare_prefix (delimiter_type) {}
bool
operator() (const key_type& x, const key_type& y) const
{
const string_type& xs (x.string ());
const string_type& ys (y.string ());
return compare (xs.c_str (),
root (xs) ? 0 : xs.size (),
ys.c_str (),
root (ys) ? 0 : ys.size ()) < 0;
}
bool
prefix (const key_type& p, const key_type& k) const
{
const string_type& ps (p.string ());
const string_type& ks (k.string ());
return prefix (root (ps) ? string_type () : ps,
root (ks) ? string_type () : ks);
}
protected:
bool
prefix (const string_type& p, const string_type& k) const
{
// The same code as in prefix_map but using our compare().
//
size_type pn (p.size ()), kn (k.size ());
return pn == 0 || // Empty key is always a prefix.
(pn <= kn &&
compare (p.c_str (), pn, k.c_str (), pn == kn ? pn : pn + 1) == 0);
}
int
compare (const C* x, size_type xn,
const C* y, size_type yn) const
{
size_type n (std::min (xn, yn));
int r (traits_type::compare (x, n, y, n));
if (r == 0)
{
// Pretend there is a delimiter characters at the end of the
// shorter string.
//
char xc (xn > n ? x[n] : (xn++, traits_type::directory_separator));
char yc (yn > n ? y[n] : (yn++, traits_type::directory_separator));
r = traits_type::compare (&xc, 1, &yc, 1);
// If we are still equal, then compare the lengths.
//
if (r == 0)
r = (xn == yn ? 0 : (xn < yn ? -1 : 1));
}
return r;
}
static bool
root (const string_type& p)
{
return p.size () == 1 && key_type::traits::is_separator (p[0]);
}
};
// Note that the delimiter character is not used (is_delimiter() from
// path_traits is used instead).
//
template <typename T>
using path_map = prefix_map<path, T, path::traits::directory_separator>;
template <typename T>
using dir_path_map =
prefix_map<dir_path, T, dir_path::traits::directory_separator>;
}
#endif // BUTL_PATH_MAP
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