1 /* ftruncate emulations for native Windows.
2 Copyright (C) 1992-2020 Free Software Foundation, Inc.
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 3, or (at your option)
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License along
15 with this program; if not, see <https://www.gnu.org/licenses/>. */
23 /* A native Windows platform. */
27 # if _GL_WINDOWS_64_BIT_OFF_T
29 /* Large File Support: off_t is 64-bit, but _chsize() takes only a 32-bit
30 argument. So, define a 64-bit safe SetFileSize function ourselves. */
32 /* Ensure that <windows.h> declares GetFileSizeEx. */
33 # if !defined _WIN32_WINNT || (_WIN32_WINNT < _WIN32_WINNT_WIN2K)
35 # define _WIN32_WINNT _WIN32_WINNT_WIN2K
38 /* Get declarations of the native Windows API functions. */
39 # define WIN32_LEAN_AND_MEAN
42 /* Get _get_osfhandle. */
43 # if GNULIB_MSVC_NOTHROW
44 # include "msvc-nothrow.h"
50 SetFileSize (HANDLE h
, LONGLONG size
)
52 LARGE_INTEGER old_size
;
54 if (!GetFileSizeEx (h
, &old_size
))
57 if (size
!= old_size
.QuadPart
)
59 /* Duplicate the handle, so we are free to modify its file position. */
60 HANDLE curr_process
= GetCurrentProcess ();
63 if (!DuplicateHandle (curr_process
, /* SourceProcessHandle */
65 curr_process
, /* TargetProcessHandle */
66 (PHANDLE
) &tmph
, /* TargetHandle */
67 (DWORD
) 0, /* DesiredAccess */
68 FALSE
, /* InheritHandle */
69 DUPLICATE_SAME_ACCESS
)) /* Options */
72 if (size
< old_size
.QuadPart
)
74 /* Reduce the size. */
75 LONG size_hi
= (LONG
) (size
>> 32);
76 if (SetFilePointer (tmph
, (LONG
) size
, &size_hi
, FILE_BEGIN
)
77 == INVALID_SET_FILE_POINTER
78 && GetLastError() != NO_ERROR
)
83 if (!SetEndOfFile (tmph
))
91 /* Increase the size by adding zero bytes at the end. */
92 static char zero_bytes
[1024];
94 LONG pos_lo
= SetFilePointer (tmph
, (LONG
) 0, &pos_hi
, FILE_END
);
96 if (pos_lo
== INVALID_SET_FILE_POINTER
97 && GetLastError() != NO_ERROR
)
102 pos
= ((LONGLONG
) pos_hi
<< 32) | (ULONGLONG
) (ULONG
) pos_lo
;
106 LONGLONG count
= size
- pos
;
107 if (count
> sizeof (zero_bytes
))
108 count
= sizeof (zero_bytes
);
109 if (!WriteFile (tmph
, zero_bytes
, (DWORD
) count
, &written
, NULL
)
115 pos
+= (ULONGLONG
) (ULONG
) written
;
118 /* Close the handle. */
125 ftruncate (int fd
, off_t length
)
127 HANDLE handle
= (HANDLE
) _get_osfhandle (fd
);
129 if (handle
== INVALID_HANDLE_VALUE
)
139 if (!SetFileSize (handle
, length
))
141 switch (GetLastError ())
143 case ERROR_ACCESS_DENIED
:
146 case ERROR_HANDLE_DISK_FULL
:
147 case ERROR_DISK_FULL
:
148 case ERROR_DISK_TOO_FRAGMENTED
:
164 # if HAVE_MSVC_INVALID_PARAMETER_HANDLER
165 # include "msvc-inval.h"
167 chsize_nothrow (int fd
, long length
)
173 result
= _chsize (fd
, length
);
185 # define chsize_nothrow _chsize
189 ftruncate (int fd
, off_t length
)
191 return chsize_nothrow (fd
, length
);