lib/pathcch/pathcch.c

/*
 * Copyright 2018 Nikolay Sivov
 * Copyright 2018 Zhiyi Zhang
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */

#include <stdarg.h>
#include <string.h>

/* Wine code is still stuck in the past... */
#ifdef __REACTOS__
#define wcsnicmp _wcsnicmp
#endif

#include <windef.h>
#include <winbase.h>

/* The PathCch functions use size_t, but Wine's implementation uses SIZE_T,
 * so temporarily change the define'd SIZE_T type to the compatible one... */
#ifdef __REACTOS__
#undef SIZE_T
#define SIZE_T size_t
#endif

/* This is the static implementation of the PathCch functions */
#define STATIC_PATHCCH
#ifdef __GNUC__ // GCC doesn't support #pragma deprecated()
#undef DEPRECATE_SUPPORTED
#endif
#include <pathcch.h>

#include <strsafe.h>

#include "wine/debug.h"

WINE_DEFAULT_DEBUG_CHANNEL(path);

#ifdef __REACTOS__
#if (_WIN32_WINNT < _WIN32_WINNT_VISTA) || (DLL_EXPORT_VERSION < _WIN32_WINNT_VISTA)
/* wcsnlen is an NT6+ function. To cover all cases, use a private implementation */
static inline size_t hacked_wcsnlen(const wchar_t* str, size_t size)
{
    StringCchLengthW(str, size, &size);
    return size;
}
#define wcsnlen hacked_wcsnlen
#endif
#endif /* __REACTOS__ */

static BOOL is_drive_spec( const WCHAR *str )
{
    return isalpha( str[0] ) && str[1] == ':';
}

#if 0
static BOOL is_escaped_drive_spec( const WCHAR *str )
{
    return isalpha( str[0] ) && (str[1] == ':' || str[1] == '|');
}
#endif

static BOOL is_prefixed_unc(const WCHAR *string)
{
    return !wcsnicmp(string, L"\\\\?\\UNC\\", 8 );
}

static BOOL is_prefixed_disk(const WCHAR *string)
{
    return !wcsncmp(string, L"\\\\?\\", 4) && is_drive_spec( string + 4 );
}

static BOOL is_prefixed_volume(const WCHAR *string)
{
    const WCHAR *guid;
    INT i = 0;

    if (wcsnicmp( string, L"\\\\?\\Volume", 10 )) return FALSE;

    guid = string + 10;

    while (i <= 37)
    {
        switch (i)
        {
        case 0:
            if (guid[i] != '{') return FALSE;
            break;
        case 9:
        case 14:
        case 19:
        case 24:
            if (guid[i] != '-') return FALSE;
            break;
        case 37:
            if (guid[i] != '}') return FALSE;
            break;
        default:
            if (!isxdigit(guid[i])) return FALSE;
            break;
        }
        i++;
    }

    return TRUE;
}

/* Get the next character beyond end of the segment.
   Return TRUE if the last segment ends with a backslash */
static BOOL get_next_segment(const WCHAR *next, const WCHAR **next_segment)
{
    while (*next && *next != '\\') next++;
    if (*next == '\\')
    {
        *next_segment = next + 1;
        return TRUE;
    }
    else
    {
        *next_segment = next;
        return FALSE;
    }
}

/* Find the last character of the root in a path, if there is one, without any segments */
static const WCHAR *get_root_end(const WCHAR *path)
{
    /* Find path root */
    if (is_prefixed_volume(path))
        return path[48] == '\\' ? path + 48 : path + 47;
    else if (is_prefixed_unc(path))
        return path + 7;
    else if (is_prefixed_disk(path))
        return path[6] == '\\' ? path + 6 : path + 5;
    /* \\ */
    else if (path[0] == '\\' && path[1] == '\\')
        return path + 1;
    /* \ */
    else if (path[0] == '\\')
        return path;
    /* X:\ */
    else if (is_drive_spec( path ))
        return path[2] == '\\' ? path + 2 : path + 1;
    else
        return NULL;
}

#ifdef __REACTOS__
HRESULT
APIENTRY
PathAllocCanonicalize(
    _In_ PCWSTR path_in,
    _In_ /* PATHCCH_OPTIONS */ ULONG flags,
    _Outptr_ PWSTR* path_out)
#else
HRESULT WINAPI PathAllocCanonicalize(const WCHAR *path_in, DWORD flags, WCHAR **path_out)
#endif
{
    WCHAR *buffer, *dst;
    const WCHAR *src;
    const WCHAR *root_end;
    SIZE_T buffer_size, length;

    TRACE("%s %#lx %p\n", debugstr_w(path_in), flags, path_out);

    if (!path_in || !path_out
        || ((flags & PATHCCH_FORCE_ENABLE_LONG_NAME_PROCESS) && (flags & PATHCCH_FORCE_DISABLE_LONG_NAME_PROCESS))
        || (flags & (PATHCCH_FORCE_ENABLE_LONG_NAME_PROCESS | PATHCCH_FORCE_DISABLE_LONG_NAME_PROCESS)
            && !(flags & PATHCCH_ALLOW_LONG_PATHS))
        || ((flags & PATHCCH_ENSURE_IS_EXTENDED_LENGTH_PATH) && (flags & PATHCCH_ALLOW_LONG_PATHS)))
    {
        if (path_out) *path_out = NULL;
        return E_INVALIDARG;
    }

    length = lstrlenW(path_in);
    if ((length + 1 > MAX_PATH && !(flags & (PATHCCH_ALLOW_LONG_PATHS | PATHCCH_ENSURE_IS_EXTENDED_LENGTH_PATH)))
        || (length + 1 > PATHCCH_MAX_CCH))
    {
        *path_out = NULL;
        return HRESULT_FROM_WIN32(ERROR_FILENAME_EXCED_RANGE);
    }

    /* PATHCCH_ENSURE_IS_EXTENDED_LENGTH_PATH implies PATHCCH_DO_NOT_NORMALIZE_SEGMENTS */
    if (flags & PATHCCH_ENSURE_IS_EXTENDED_LENGTH_PATH) flags |= PATHCCH_DO_NOT_NORMALIZE_SEGMENTS;

    /* path length + possible \\?\ addition + possible \ addition + NUL */
    buffer_size = (length + 6) * sizeof(WCHAR);
    buffer = LocalAlloc(LMEM_ZEROINIT, buffer_size);
    if (!buffer)
    {
        *path_out = NULL;
        return E_OUTOFMEMORY;
    }

    src = path_in;
    dst = buffer;

    root_end = get_root_end(path_in);
    if (root_end) root_end = buffer + (root_end - path_in);

    /* Copy path root */
    if (root_end)
    {
        memcpy(dst, src, (root_end - buffer + 1) * sizeof(WCHAR));
        src += root_end - buffer + 1;
        if(PathCchStripPrefix(dst, length + 6) == S_OK)
        {
            /* Fill in \ in X:\ if the \ is missing */
            if (is_drive_spec( dst ) && dst[2]!= '\\')
            {
                dst[2] = '\\';
                dst[3] = 0;
            }
            dst = buffer + lstrlenW(buffer);
            root_end = dst;
        }
        else
            dst += root_end - buffer + 1;
    }

    while (*src)
    {
        if (src[0] == '.')
        {
            if (src[1] == '.')
            {
                /* Keep one . after * */
                if (dst > buffer && dst[-1] == '*')
                {
                    *dst++ = *src++;
                    continue;
                }

                /* Keep the .. if not surrounded by \ */
                if ((src[2] != '\\' && src[2]) || (dst > buffer && dst[-1] != '\\'))
                {
                    *dst++ = *src++;
                    *dst++ = *src++;
                    continue;
                }

                /* Remove the \ before .. if the \ is not part of root */
                if (dst > buffer && dst[-1] == '\\' && (!root_end || dst - 1 > root_end))
                {
                    *--dst = '\0';
                    /* Remove characters until a \ is encountered */
                    while (dst > buffer)
                    {
                        if (dst[-1] == '\\')
                        {
                            *--dst = 0;
                            break;
                        }
                        else
                            *--dst = 0;
                    }
                }
                /* Remove the extra \ after .. if the \ before .. wasn't deleted */
                else if (src[2] == '\\')
                    src++;

                src += 2;
            }
            else
            {
                /* Keep the . if not surrounded by \ */
                if ((src[1] != '\\' && src[1]) || (dst > buffer && dst[-1] != '\\'))
                {
                    *dst++ = *src++;
                    continue;
                }

                /* Remove the \ before . if the \ is not part of root */
                if (dst > buffer && dst[-1] == '\\' && (!root_end || dst - 1 > root_end)) dst--;
                /* Remove the extra \ after . if the \ before . wasn't deleted */
                else if (src[1] == '\\')
                    src++;

                src++;
            }

            /* If X:\ is not complete, then complete it */
            if (is_drive_spec( buffer ) && buffer[2] != '\\')
            {
                root_end = buffer + 2;
                dst = buffer + 3;
                buffer[2] = '\\';
                /* If next character is \, use the \ to fill in */
                if (src[0] == '\\') src++;
            }
        }
        /* Copy over */
        else
            *dst++ = *src++;
    }
    /* End the path */
    *dst = 0;

    /* Strip multiple trailing . */
    if (!(flags & PATHCCH_DO_NOT_NORMALIZE_SEGMENTS))
    {
        while (dst > buffer && dst[-1] == '.')
        {
            /* Keep a . after * */
            if (dst - 1 > buffer && dst[-2] == '*')
                break;
            /* If . follow a : at the second character, remove the . and add a \ */
            else if (dst - 1 > buffer && dst[-2] == ':' && dst - 2 == buffer + 1)
                *--dst = '\\';
            else
                *--dst = 0;
        }
    }

    /* If result path is empty, fill in \ */
    if (!*buffer)
    {
        buffer[0] = '\\';
        buffer[1] = 0;
    }

    /* Extend the path if needed */
    length = lstrlenW(buffer);
    if (((length + 1 > MAX_PATH && is_drive_spec( buffer ))
         || (is_drive_spec( buffer ) && flags & PATHCCH_ENSURE_IS_EXTENDED_LENGTH_PATH))
        && !(flags & PATHCCH_FORCE_ENABLE_LONG_NAME_PROCESS))
    {
        memmove(buffer + 4, buffer, (length + 1) * sizeof(WCHAR));
        buffer[0] = '\\';
        buffer[1] = '\\';
        buffer[2] = '?';
        buffer[3] = '\\';
    }

    /* Add a trailing backslash to the path if needed */
    if (flags & PATHCCH_ENSURE_TRAILING_SLASH)
        PathCchAddBackslash(buffer, buffer_size);

    *path_out = buffer;
    return S_OK;
}

#ifdef __REACTOS__
HRESULT
APIENTRY
PathAllocCombine(
    _In_opt_ PCWSTR path1,
    _In_opt_ PCWSTR path2,
    _In_ /* PATHCCH_OPTIONS */ ULONG flags,
    _Outptr_ PWSTR* out)
#else
HRESULT WINAPI PathAllocCombine(const WCHAR *path1, const WCHAR *path2, DWORD flags, WCHAR **out)
#endif
{
    SIZE_T combined_length, length2;
    WCHAR *combined_path;
    BOOL add_backslash = FALSE;
    HRESULT hr;

    TRACE("%s %s %#lx %p\n", wine_dbgstr_w(path1), wine_dbgstr_w(path2), flags, out);

    if ((!path1 && !path2) || !out)
    {
        if (out) *out = NULL;
        return E_INVALIDARG;
    }

    if (!path1 || !path2) return PathAllocCanonicalize(path1 ? path1 : path2, flags, out);

    /* If path2 is fully qualified, use path2 only */
    if (is_drive_spec( path2 ) || (path2[0] == '\\' && path2[1] == '\\'))
    {
        path1 = path2;
        path2 = NULL;
        add_backslash = (is_drive_spec(path1) && !path1[2])
                        || (is_prefixed_disk(path1) && !path1[6]);
    }

    length2 = path2 ? lstrlenW(path2) : 0;
    /* path1 length + path2 length + possible backslash + NULL */
    combined_length = lstrlenW(path1) + length2 + 2;

    combined_path = HeapAlloc(GetProcessHeap(), 0, combined_length * sizeof(WCHAR));
    if (!combined_path)
    {
        *out = NULL;
        return E_OUTOFMEMORY;
    }

    lstrcpyW(combined_path, path1);
    PathCchStripPrefix(combined_path, combined_length);
    if (add_backslash) PathCchAddBackslashEx(combined_path, combined_length, NULL, NULL);

    if (path2 && path2[0])
    {
        if (path2[0] == '\\' && path2[1] != '\\')
        {
            PathCchStripToRoot(combined_path, combined_length);
            path2++;
        }

        PathCchAddBackslashEx(combined_path, combined_length, NULL, NULL);
        lstrcatW(combined_path, path2);
    }

    hr = PathAllocCanonicalize(combined_path, flags, out);
    HeapFree(GetProcessHeap(), 0, combined_path);
    return hr;
}

#ifdef __REACTOS__
HRESULT
APIENTRY
PathCchAddBackslash(
    _Inout_updates_(size) PWSTR path,
    _In_ size_t size)
#else
HRESULT WINAPI PathCchAddBackslash(WCHAR *path, SIZE_T size)
#endif
{
    return PathCchAddBackslashEx(path, size, NULL, NULL);
}

#ifdef __REACTOS__
HRESULT
APIENTRY
PathCchAddBackslashEx(
    _Inout_updates_(size) PWSTR path,
    _In_ size_t size,
    _Outptr_opt_result_buffer_(*remaining) PWSTR* endptr,
    _Out_opt_ size_t* remaining)
#else
HRESULT WINAPI PathCchAddBackslashEx(WCHAR *path, SIZE_T size, WCHAR **endptr, SIZE_T *remaining)
#endif
{
    BOOL needs_termination;
    SIZE_T length;

    TRACE("%s, %Iu, %p, %p\n", debugstr_w(path), size, endptr, remaining);

    length = lstrlenW(path);
    needs_termination = size && length && path[length - 1] != '\\';

    if (length >= (needs_termination ? size - 1 : size))
    {
        if (endptr) *endptr = NULL;
        if (remaining) *remaining = 0;
        return STRSAFE_E_INSUFFICIENT_BUFFER;
    }

    if (!needs_termination)
    {
        if (endptr) *endptr = path + length;
        if (remaining) *remaining = size - length;
        return S_FALSE;
    }

    path[length++] = '\\';
    path[length] = 0;

    if (endptr) *endptr = path + length;
    if (remaining) *remaining = size - length;

    return S_OK;
}

#ifdef __REACTOS__
HRESULT
APIENTRY
PathCchAddExtension(
    _Inout_updates_(size) PWSTR path,
    _In_ size_t size,
    _In_ PCWSTR extension)
#else
HRESULT WINAPI PathCchAddExtension(WCHAR *path, SIZE_T size, const WCHAR *extension)
#endif
{
    const WCHAR *existing_extension, *next;
    SIZE_T path_length, extension_length, dot_length;
    BOOL has_dot;
    HRESULT hr;

    TRACE("%s %Iu %s\n", wine_dbgstr_w(path), size, wine_dbgstr_w(extension));

    if (!path || !size || size > PATHCCH_MAX_CCH || !extension) return E_INVALIDARG;

    next = extension;
    while (*next)
    {
        if ((*next == '.' && next > extension) || *next == ' ' || *next == '\\') return E_INVALIDARG;
        next++;
    }

    has_dot = extension[0] == '.';

    hr = PathCchFindExtension(path, size, &existing_extension);
    if (FAILED(hr)) return hr;
    if (*existing_extension) return S_FALSE;

    path_length = wcsnlen(path, size);
    dot_length = has_dot ? 0 : 1;
    extension_length = lstrlenW(extension);

    if (path_length + dot_length + extension_length + 1 > size) return STRSAFE_E_INSUFFICIENT_BUFFER;

    /* If extension is empty or only dot, return S_OK with path unchanged */
    if (!extension[0] || (extension[0] == '.' && !extension[1])) return S_OK;

    if (!has_dot)
    {
        path[path_length] = '.';
        path_length++;
    }

    lstrcpyW(path + path_length, extension);
    return S_OK;
}

#ifdef __REACTOS__
HRESULT
APIENTRY
PathCchAppend(
    _Inout_updates_(size) PWSTR path1,
    _In_ size_t size,
    _In_opt_ PCWSTR path2)
#else
HRESULT WINAPI PathCchAppend(WCHAR *path1, SIZE_T size, const WCHAR *path2)
#endif
{
    TRACE("%s %Iu %s\n", wine_dbgstr_w(path1), size, wine_dbgstr_w(path2));

    return PathCchAppendEx(path1, size, path2, PATHCCH_NONE);
}

#ifdef __REACTOS__
HRESULT
APIENTRY
PathCchAppendEx(
    _Inout_updates_(size) PWSTR path1,
    _In_ size_t size,
    _In_opt_ PCWSTR path2,
    _In_ /* PATHCCH_OPTIONS */ ULONG flags)
#else
HRESULT WINAPI PathCchAppendEx(WCHAR *path1, SIZE_T size, const WCHAR *path2, DWORD flags)
#endif
{
    HRESULT hr;
    WCHAR *result;

    TRACE("%s %Iu %s %#lx\n", wine_dbgstr_w(path1), size, wine_dbgstr_w(path2), flags);

    if (!path1 || !size) return E_INVALIDARG;

    /* Create a temporary buffer for result because we need to keep path1 unchanged if error occurs.
     * And PathCchCombineEx writes empty result if there is error so we can't just use path1 as output
     * buffer for PathCchCombineEx */
    result = HeapAlloc(GetProcessHeap(), 0, size * sizeof(WCHAR));
    if (!result) return E_OUTOFMEMORY;

    /* Avoid the single backslash behavior with PathCchCombineEx when appending */
    if (path2 && path2[0] == '\\' && path2[1] != '\\') path2++;

    hr = PathCchCombineEx(result, size, path1, path2, flags);
    if (SUCCEEDED(hr)) memcpy(path1, result, size * sizeof(WCHAR));

    HeapFree(GetProcessHeap(), 0, result);
    return hr;
}

#ifdef __REACTOS__
HRESULT
APIENTRY
PathCchCanonicalize(
    _Out_writes_(size) PWSTR out,
    _In_ size_t size,
    _In_ PCWSTR in)
#else
HRESULT WINAPI PathCchCanonicalize(WCHAR *out, SIZE_T size, const WCHAR *in)
#endif
{
    TRACE("%p %Iu %s\n", out, size, wine_dbgstr_w(in));

    /* Not X:\ and path > MAX_PATH - 4, return HRESULT_FROM_WIN32(ERROR_FILENAME_EXCED_RANGE) */
    if (lstrlenW(in) > MAX_PATH - 4 && !(is_drive_spec( in ) && in[2] == '\\'))
        return HRESULT_FROM_WIN32(ERROR_FILENAME_EXCED_RANGE);

    return PathCchCanonicalizeEx(out, size, in, PATHCCH_NONE);
}

#ifdef __REACTOS__
HRESULT
APIENTRY
PathCchCanonicalizeEx(
    _Out_writes_(size) PWSTR out,
    _In_ size_t size,
    _In_ PCWSTR in,
    _In_ /* PATHCCH_OPTIONS */ ULONG flags)
#else
HRESULT WINAPI PathCchCanonicalizeEx(WCHAR *out, SIZE_T size, const WCHAR *in, DWORD flags)
#endif
{
    WCHAR *buffer;
    SIZE_T length;
    HRESULT hr;

    TRACE("%p %Iu %s %#lx\n", out, size, wine_dbgstr_w(in), flags);

    if (!size) return E_INVALIDARG;

    hr = PathAllocCanonicalize(in, flags, &buffer);
    if (FAILED(hr)) return hr;

    length = lstrlenW(buffer);
    if (size < length + 1)
    {
        /* No root and path > MAX_PATH - 4, return HRESULT_FROM_WIN32(ERROR_FILENAME_EXCED_RANGE) */
        if (length > MAX_PATH - 4 && !(in[0] == '\\' || (is_drive_spec( in ) && in[2] == '\\')))
            hr = HRESULT_FROM_WIN32(ERROR_FILENAME_EXCED_RANGE);
        else
            hr = STRSAFE_E_INSUFFICIENT_BUFFER;
    }

    if (SUCCEEDED(hr))
    {
        memcpy(out, buffer, (length + 1) * sizeof(WCHAR));

        /* Fill a backslash at the end of X: */
        if (is_drive_spec( out ) && !out[2] && size > 3)
        {
            out[2] = '\\';
            out[3] = 0;
        }
    }

    LocalFree(buffer);
    return hr;
}

#ifdef __REACTOS__
HRESULT
APIENTRY
PathCchCombine(
    _Out_writes_(size) PWSTR out,
    _In_ size_t size,
    _In_opt_ PCWSTR path1,
    _In_opt_ PCWSTR path2)
#else
HRESULT WINAPI PathCchCombine(WCHAR *out, SIZE_T size, const WCHAR *path1, const WCHAR *path2)
#endif
{
    TRACE("%p %s %s\n", out, wine_dbgstr_w(path1), wine_dbgstr_w(path2));

    return PathCchCombineEx(out, size, path1, path2, PATHCCH_NONE);
}

#ifdef __REACTOS__
HRESULT
APIENTRY
PathCchCombineEx(
    _Out_writes_(size) PWSTR out,
    _In_ size_t size,
    _In_opt_ PCWSTR path1,
    _In_opt_ PCWSTR path2,
    _In_ /* PATHCCH_OPTIONS */ ULONG flags)
#else
HRESULT WINAPI PathCchCombineEx(WCHAR *out, SIZE_T size, const WCHAR *path1, const WCHAR *path2, DWORD flags)
#endif
{
    HRESULT hr;
    WCHAR *buffer;
    SIZE_T length;

    TRACE("%p %s %s %#lx\n", out, wine_dbgstr_w(path1), wine_dbgstr_w(path2), flags);

    if (!out || !size || size > PATHCCH_MAX_CCH) return E_INVALIDARG;

    hr = PathAllocCombine(path1, path2, flags, &buffer);
    if (FAILED(hr))
    {
        out[0] = 0;
        return hr;
    }

    length = lstrlenW(buffer);
    if (length + 1 > size)
    {
        out[0] = 0;
        LocalFree(buffer);
        return STRSAFE_E_INSUFFICIENT_BUFFER;
    }
    else
    {
        memcpy(out, buffer, (length + 1) * sizeof(WCHAR));
        LocalFree(buffer);
        return S_OK;
    }
}

#ifdef __REACTOS__
HRESULT
APIENTRY
PathCchFindExtension(
    _In_reads_(size) PCWSTR path,
    _In_ size_t size,
    _Outptr_ PCWSTR* extension)
#else
HRESULT WINAPI PathCchFindExtension(const WCHAR *path, SIZE_T size, const WCHAR **extension)
#endif
{
    const WCHAR *lastpoint = NULL;
    SIZE_T counter = 0;

    TRACE("%s %Iu %p\n", wine_dbgstr_w(path), size, extension);

    if (!path || !size || size > PATHCCH_MAX_CCH)
    {
        *extension = NULL;
        return E_INVALIDARG;
    }

    while (*path)
    {
        if (*path == '\\' || *path == ' ')
            lastpoint = NULL;
        else if (*path == '.')
            lastpoint = path;

        path++;
        counter++;
        if (counter == size || counter == PATHCCH_MAX_CCH)
        {
            *extension = NULL;
            return E_INVALIDARG;
        }
    }

    *extension = lastpoint ? lastpoint : path;
    return S_OK;
}

#ifdef __REACTOS__
BOOL
APIENTRY
PathCchIsRoot(
    _In_opt_ PCWSTR path)
#else
BOOL WINAPI PathCchIsRoot(const WCHAR *path)
#endif
{
    const WCHAR *root_end;
    const WCHAR *next;
    BOOL is_unc;

    TRACE("%s\n", wine_dbgstr_w(path));

    if (!path || !*path) return FALSE;

    root_end = get_root_end(path);
    if (!root_end) return FALSE;

    if ((is_unc = is_prefixed_unc(path)) || (path[0] == '\\' && path[1] == '\\' && path[2] != '?'))
    {
        next = root_end + 1;
        /* No extra segments */
        if ((is_unc && !*next) || (!is_unc && !*next)) return TRUE;

        /* Has first segment with an ending backslash but no remaining characters */
        if (get_next_segment(next, &next) && !*next) return FALSE;
        /* Has first segment with no ending backslash */
        else if (!*next)
            return TRUE;
        /* Has first segment with an ending backslash and has remaining characters*/
        else
        {
            next++;
            /* Second segment must have no backslash and no remaining characters */
            return !get_next_segment(next, &next) && !*next;
        }
    }
    else if (*root_end == '\\' && !root_end[1])
        return TRUE;
    else
        return FALSE;
}

#ifdef __REACTOS__
HRESULT
APIENTRY
PathCchRemoveBackslash(
    _Inout_updates_(path_size) PWSTR path,
    _In_ size_t path_size)
#else
HRESULT WINAPI PathCchRemoveBackslash(WCHAR *path, SIZE_T path_size)
#endif
{
    WCHAR *path_end;
    SIZE_T free_size;

    TRACE("%s %Iu\n", debugstr_w(path), path_size);

    return PathCchRemoveBackslashEx(path, path_size, &path_end, &free_size);
}

#ifdef __REACTOS__
HRESULT
APIENTRY
PathCchRemoveBackslashEx(
    _Inout_updates_(path_size) PWSTR path,
    _In_ size_t path_size,
    _Outptr_opt_result_buffer_(*free_size) PWSTR* path_end,
    _Out_opt_ size_t* free_size)
#else
HRESULT WINAPI PathCchRemoveBackslashEx(WCHAR *path, SIZE_T path_size, WCHAR **path_end, SIZE_T *free_size)
#endif
{
    const WCHAR *root_end;
    SIZE_T path_length;

    TRACE("%s %Iu %p %p\n", debugstr_w(path), path_size, path_end, free_size);

    if (!path_size || !path_end || !free_size)
    {
        if (path_end) *path_end = NULL;
        if (free_size) *free_size = 0;
        return E_INVALIDARG;
    }

    path_length = wcsnlen(path, path_size);
    if (path_length == path_size && !path[path_length]) return E_INVALIDARG;

    root_end = get_root_end(path);
    if (path_length > 0 && path[path_length - 1] == '\\')
    {
        *path_end = path + path_length - 1;
        *free_size = path_size - path_length + 1;
        /* If the last character is beyond end of root */
        if (!root_end || path + path_length - 1 > root_end)
        {
            path[path_length - 1] = 0;
            return S_OK;
        }
        else
            return S_FALSE;
    }
    else
    {
        *path_end = path + path_length;
        *free_size = path_size - path_length;
        return S_FALSE;
    }
}

#ifdef __REACTOS__
HRESULT
APIENTRY
PathCchRemoveExtension(
    _Inout_updates_(size) PWSTR path,
    _In_ size_t size)
#else
HRESULT WINAPI PathCchRemoveExtension(WCHAR *path, SIZE_T size)
#endif
{
    const WCHAR *extension;
    WCHAR *next;
    HRESULT hr;

    TRACE("%s %Iu\n", wine_dbgstr_w(path), size);

    if (!path || !size || size > PATHCCH_MAX_CCH) return E_INVALIDARG;

    hr = PathCchFindExtension(path, size, &extension);
    if (FAILED(hr)) return hr;

    next = path + (extension - path);
    while (next - path < size && *next) *next++ = 0;

    return next == extension ? S_FALSE : S_OK;
}

#ifdef __REACTOS__
HRESULT
APIENTRY
PathCchRemoveFileSpec(
    _Inout_updates_(size) PWSTR path,
    _In_ size_t size)
#else
HRESULT WINAPI PathCchRemoveFileSpec(WCHAR *path, SIZE_T size)
#endif
{
    const WCHAR *root_end = NULL;
    SIZE_T length;
    WCHAR *last;

    TRACE("%s %Iu\n", wine_dbgstr_w(path), size);

    if (!path || !size || size > PATHCCH_MAX_CCH) return E_INVALIDARG;

    if (PathCchIsRoot(path)) return S_FALSE;

    PathCchSkipRoot(path, &root_end);

    /* The backslash at the end of UNC and \\* are not considered part of root in this case */
    if (root_end && root_end > path && root_end[-1] == '\\'
        && (is_prefixed_unc(path) || (path[0] == '\\' && path[1] == '\\' && path[2] != '?')))
        root_end--;

    length = lstrlenW(path);
    last = path + length - 1;
    while (last >= path && (!root_end || last >= root_end))
    {
        if (last - path >= size) return E_INVALIDARG;

        if (*last == '\\')
        {
            *last-- = 0;
            break;
        }

        *last-- = 0;
    }

    return last != path + length - 1 ? S_OK : S_FALSE;
}

#ifdef __REACTOS__
HRESULT
APIENTRY
PathCchRenameExtension(
    _Inout_updates_(size) PWSTR path,
    _In_ size_t size,
    _In_ PCWSTR extension)
#else
HRESULT WINAPI PathCchRenameExtension(WCHAR *path, SIZE_T size, const WCHAR *extension)
#endif
{
    HRESULT hr;

    TRACE("%s %Iu %s\n", wine_dbgstr_w(path), size, wine_dbgstr_w(extension));

    hr = PathCchRemoveExtension(path, size);
    if (FAILED(hr)) return hr;

    hr = PathCchAddExtension(path, size, extension);
    return FAILED(hr) ? hr : S_OK;
}

#ifdef __REACTOS__
HRESULT
APIENTRY
PathCchSkipRoot(
    _In_ PCWSTR path,
    _Outptr_ PCWSTR* root_end)
#else
HRESULT WINAPI PathCchSkipRoot(const WCHAR *path, const WCHAR **root_end)
#endif
{
    TRACE("%s %p\n", debugstr_w(path), root_end);

    if (!path || !path[0] || !root_end
        || (!wcsnicmp(path, L"\\\\?", 3) && !is_prefixed_volume(path) && !is_prefixed_unc(path)
            && !is_prefixed_disk(path)))
        return E_INVALIDARG;

    *root_end = get_root_end(path);
    if (*root_end)
    {
        (*root_end)++;
        if (is_prefixed_unc(path))
        {
            get_next_segment(*root_end, root_end);
            get_next_segment(*root_end, root_end);
        }
        else if (path[0] == '\\' && path[1] == '\\' && path[2] != '?')
        {
            /* Skip share server */
            get_next_segment(*root_end, root_end);
            /* If mount point is empty, don't skip over mount point */
            if (**root_end != '\\') get_next_segment(*root_end, root_end);
        }
    }

    return *root_end ? S_OK : E_INVALIDARG;
}

#ifdef __REACTOS__
HRESULT
APIENTRY
PathCchStripPrefix(
    _Inout_updates_(size) PWSTR path,
    _In_ size_t size)
#else
HRESULT WINAPI PathCchStripPrefix(WCHAR *path, SIZE_T size)
#endif
{
    TRACE("%s %Iu\n", wine_dbgstr_w(path), size);

    if (!path || !size || size > PATHCCH_MAX_CCH) return E_INVALIDARG;

    if (is_prefixed_unc(path))
    {
        /* \\?\UNC\a -> \\a */
        if (size < lstrlenW(path + 8) + 3) return E_INVALIDARG;
        lstrcpyW(path + 2, path + 8);
        return S_OK;
    }
    else if (is_prefixed_disk(path))
    {
        /* \\?\C:\ -> C:\ */
        if (size < lstrlenW(path + 4) + 1) return E_INVALIDARG;
        lstrcpyW(path, path + 4);
        return S_OK;
    }
    else
        return S_FALSE;
}

#ifdef __REACTOS__
HRESULT
APIENTRY
PathCchStripToRoot(
    _Inout_updates_(size) PWSTR path,
    _In_ size_t size)
#else
HRESULT WINAPI PathCchStripToRoot(WCHAR *path, SIZE_T size)
#endif
{
    const WCHAR *root_end;
    WCHAR *segment_end;
    BOOL is_unc;

    TRACE("%s %Iu\n", wine_dbgstr_w(path), size);

    if (!path || !*path || !size || size > PATHCCH_MAX_CCH) return E_INVALIDARG;

    /* \\\\?\\UNC\\* and \\\\* have to have at least two extra segments to be striped,
     * e.g. \\\\?\\UNC\\a\\b\\c -> \\\\?\\UNC\\a\\b
     *      \\\\a\\b\\c         -> \\\\a\\b         */
    if ((is_unc = is_prefixed_unc(path)) || (path[0] == '\\' && path[1] == '\\' && path[2] != '?'))
    {
        root_end = is_unc ? path + 8 : path + 3;
        if (!get_next_segment(root_end, &root_end)) return S_FALSE;
        if (!get_next_segment(root_end, &root_end)) return S_FALSE;

        if (root_end - path >= size) return E_INVALIDARG;

        segment_end = path + (root_end - path) - 1;
        *segment_end = 0;
        return S_OK;
    }
    else if (PathCchSkipRoot(path, &root_end) == S_OK)
    {
        if (root_end - path >= size) return E_INVALIDARG;

        segment_end = path + (root_end - path);
        if (!*segment_end) return S_FALSE;

        *segment_end = 0;
        return S_OK;
    }
    else
        return E_INVALIDARG;
}

#ifdef __REACTOS__
BOOL
APIENTRY
PathIsUNCEx(
    _In_ PCWSTR path,
    _Outptr_opt_ PCWSTR* server)
#else
BOOL WINAPI PathIsUNCEx(const WCHAR *path, const WCHAR **server)
#endif
{
    const WCHAR *result = NULL;

    TRACE("%s %p\n", wine_dbgstr_w(path), server);

    if (is_prefixed_unc(path))
        result = path + 8;
    else if (path[0] == '\\' && path[1] == '\\' && path[2] != '?')
        result = path + 2;

    if (server) *server = result;
    return !!result;
}