81 lines
1.5 KiB
C
81 lines
1.5 KiB
C
#include <windows.h>
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#include <stdio.h>
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#include <wchar.h>
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/* Print "message: last Win32 error" to stderr. */
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void
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oops(const wchar_t *message)
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{
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wchar_t *buf;
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DWORD error;
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buf = NULL;
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error = GetLastError();
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FormatMessageW(FORMAT_MESSAGE_ALLOCATE_BUFFER |
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FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
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NULL, error, 0, (wchar_t *)&buf, 0, NULL);
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if (buf) {
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fwprintf(stderr, L"%ls: %ls", message, buf);
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LocalFree(buf);
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} else {
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/* FormatMessageW failed. */
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fwprintf(stderr, L"%ls: unknown error 0x%x\n",
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message, error);
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}
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}
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int
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dotruncate(wchar_t *fn, LARGE_INTEGER fp)
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{
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HANDLE fh;
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fh = CreateFileW(fn, GENERIC_WRITE, 0, NULL, OPEN_EXISTING, 0, NULL);
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if (fh == INVALID_HANDLE_VALUE) {
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oops(fn);
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return 1;
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}
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if (SetFilePointerEx(fh, fp, NULL, FILE_BEGIN) == 0 ||
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SetEndOfFile(fh) == 0) {
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oops(fn);
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CloseHandle(fh);
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return 1;
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}
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CloseHandle(fh);
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return 0;
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}
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/*
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* Truncate or extend a file to the given length.
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*/
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int
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main()
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{
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LARGE_INTEGER fp;
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int argc;
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wchar_t **argv, *fn, junk[2];
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/* MinGW never provides wmain(argc, argv). */
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argv = CommandLineToArgvW(GetCommandLineW(), &argc);
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if (argv == NULL) {
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oops(L"CommandLineToArgvW");
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return 1;
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}
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if (argc != 3) {
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fwprintf(stderr, L"usage: %ls filename length\n", argv[0]);
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return 1;
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}
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fn = argv[1];
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/* fp = argv[2] converted to a LARGE_INTEGER. */
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if (swscanf(argv[2], L"%lld%1ls", &fp.QuadPart, &junk) != 1) {
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fwprintf(stderr, L"%ls: not a number\n", argv[2]);
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return 1;
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}
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return dotruncate(fn, fp);
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}
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