path.cpp

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/* Copyright (c) 2010 Wildfire Games
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

/*
 * helper functions for path strings.
 */

#include "precompiled.h"
#include "lib/path.h"

#include <cstring>
#include <cerrno>

static const StatusDefinition pathStatusDefinitions[] = {
    { ERR::PATH_CHARACTER_ILLEGAL, L"illegal path character" },
    { ERR::PATH_CHARACTER_UNSAFE, L"unsafe path character" },
    { ERR::PATH_NOT_FOUND, L"path not found" },
    { ERR::PATH_MIXED_SEPARATORS, L"path contains both slash and backslash separators" }
};
STATUS_ADD_DEFINITIONS(pathStatusDefinitions);


static bool path_is_dir_sep(wchar_t c)
{
    if(c == '/' || c == '\\')
        return true;
    return false;
}

// is s2 a subpath of s1, or vice versa?
// (equal counts as subpath)
bool path_is_subpath(const wchar_t* s1, const wchar_t* s2)
{
    // make sure s1 is the shorter string
    if(wcslen(s1) > wcslen(s2))
        std::swap(s1, s2);

    wchar_t c1 = 0, last_c1, c2;
    for(;;)
    {
        last_c1 = c1;
        c1 = *s1++, c2 = *s2++;

        // end of s1 reached:
        if(c1 == '\0')
        {
            // s1 matched s2 up until:
            if((c2 == '\0') ||  // its end (i.e. they're equal length) OR
                path_is_dir_sep(c2) ||      // start of next component OR
                path_is_dir_sep(last_c1))   // ", but both have a trailing slash
                // => is subpath
                return true;
        }

        // mismatch => is not subpath
        if(c1 != c2)
            return false;
    }
}


//-----------------------------------------------------------------------------

// return pointer to the name component within path (i.e. skips over all
// characters up to the last dir separator, if any).
const wchar_t* path_name_only(const wchar_t* path)
{
    const wchar_t* slash1 = wcsrchr(path, '/');
    const wchar_t* slash2 = wcsrchr(path, '\\');
    // neither present, it's a filename only
    if(!slash1 && !slash2)
        return path;

    // return name, i.e. component after the last slash
    const wchar_t* name = std::max(slash1, slash2)+1;
    return name;
}


/*static*/ Status Path::Validate(String::value_type c)
{
    if(c < 32)
        return ERR::PATH_CHARACTER_UNSAFE;

#if !OS_WIN
    if(c >= UCHAR_MAX)
        return ERR::PATH_CHARACTER_UNSAFE;
#endif

    switch(c)
    {
    case '\\':
    case '/':
    case ':':
    case '"':
    case '?':
    case '*':
    case '<':
    case '>':
    case '|':
    case '^':
        return ERR::PATH_CHARACTER_ILLEGAL;

    default:
        return INFO::OK;
    }
}