windows-nt/Source/XPSP1/NT/base/ntsetup/pnpsif/util.c
2020-09-26 16:20:57 +08:00

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/*++
Copyright (c) 2000 Microsoft Corporation
Module Name:
util.c
Abstract:
This module contains the following private utility routines for the Plug and
Play registry merge-restore routines:
FileExists
Author:
Jim Cavalaris (jamesca) 2-10-2000
Environment:
User-mode only.
Revision History:
10-February-2000 jamesca
Creation and initial implementation.
--*/
//
// includes
//
#include "precomp.h"
//
// definitions
//
#define MAX_GUID_STRING_LEN 39 // 38 chars + terminating NULL
//
// Declare data used in GUID->string conversion (from ole32\common\ccompapi.cxx).
//
static const BYTE GuidMap[] = { 3, 2, 1, 0, '-', 5, 4, '-', 7, 6, '-',
8, 9, '-', 10, 11, 12, 13, 14, 15 };
static const TCHAR szDigits[] = TEXT("0123456789ABCDEF");
//
// routines
//
BOOL
pSifUtilFileExists(
IN PCTSTR FileName,
OUT PWIN32_FIND_DATA FindData OPTIONAL
)
/*++
Routine Description:
Determine if a file exists and is accessible.
Errormode is set (and then restored) so the user will not see
any pop-ups.
Arguments:
FileName - supplies full path of file to check for existance.
FindData - if specified, receives find data for the file.
Return Value:
TRUE if the file exists and is accessible.
FALSE if not. GetLastError() returns extended error info.
--*/
{
WIN32_FIND_DATA findData;
HANDLE FindHandle;
UINT OldMode;
DWORD Error;
OldMode = SetErrorMode(SEM_FAILCRITICALERRORS);
FindHandle = FindFirstFile(FileName,&findData);
if(FindHandle == INVALID_HANDLE_VALUE) {
Error = GetLastError();
} else {
FindClose(FindHandle);
if(FindData) {
*FindData = findData;
}
Error = NO_ERROR;
}
SetErrorMode(OldMode);
SetLastError(Error);
return (Error == NO_ERROR);
}
BOOL
pSifUtilStringFromGuid(
IN CONST GUID *Guid,
OUT PTSTR GuidString,
IN DWORD GuidStringSize
)
/*++
Routine Description:
This routine converts a GUID into a null-terminated string which represents
it. This string is of the form:
{xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}
where x represents a hexadecimal digit.
This routine comes from ole32\common\ccompapi.cxx. It is included here to avoid linking
to ole32.dll. (The RPC version allocates memory, so it was avoided as well.)
Arguments:
Guid - Supplies a pointer to the GUID whose string representation is
to be retrieved.
GuidString - Supplies a pointer to character buffer that receives the
string. This buffer must be _at least_ 39 (MAX_GUID_STRING_LEN) characters
long.
Return Value:
Returns TRUE if successful, FALSE if not.
GetLastError() returns extended error info.
--*/
{
CONST BYTE *GuidBytes;
INT i;
if(GuidStringSize < MAX_GUID_STRING_LEN) {
SetLastError(ERROR_INSUFFICIENT_BUFFER);
return FALSE;
}
GuidBytes = (CONST BYTE *)Guid;
*GuidString++ = TEXT('{');
for(i = 0; i < sizeof(GuidMap); i++) {
if(GuidMap[i] == '-') {
*GuidString++ = TEXT('-');
} else {
*GuidString++ = szDigits[ (GuidBytes[GuidMap[i]] & 0xF0) >> 4 ];
*GuidString++ = szDigits[ (GuidBytes[GuidMap[i]] & 0x0F) ];
}
}
*GuidString++ = TEXT('}');
*GuidString = TEXT('\0');
return TRUE;
}