guid.c

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/*++

Copyright (c) 1996  Microsoft Corporation

Module Name:

    guid.c

Abstract:

    This Module implements the guid manipulation functions.

Author:

    George Shaw (GShaw) 9-Oct-1996

Environment:

    Pure Runtime Library Routine

Revision History:

--*/

#include "nt.h"
#include "ntrtlp.h"

#if defined(ALLOC_PRAGMA) && defined(NTOS_KERNEL_RUNTIME)
static
int
__cdecl
ScanHexFormat(
    IN const WCHAR* Buffer,
    IN ULONG MaximumLength,
    IN const WCHAR* Format,
    ...);

#pragma alloc_text(PAGE, RtlStringFromGUID)
#pragma alloc_text(PAGE, ScanHexFormat)
#pragma alloc_text(PAGE, RtlGUIDFromString)
#endif // ALLOC_PRAGMA && NTOS_KERNEL_RUNTIME

extern const WCHAR GuidFormat[];

#define GUID_STRING_SIZE 38


NTSYSAPI
NTSTATUS
NTAPI
RtlStringFromGUID(
    IN REFGUID Guid,
    OUT PUNICODE_STRING GuidString
    )
/*++

Routine Description:

    Constructs the standard string version of a GUID, in the form:
    "{xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}".

Arguments:

    Guid -
        Contains the GUID to translate.

    GuidString -
        Returns a string that represents the textual format of the GUID.
        Caller must call RtlFreeUnicodeString to free the buffer when done with
        it.

Return Value:

    NTSTATUS - Returns STATUS_SUCCESS if the user string was succesfully
    initialized.

--*/
{
    RTL_PAGED_CODE();
    GuidString->Length = GUID_STRING_SIZE * sizeof(WCHAR);
    GuidString->MaximumLength = GuidString->Length + sizeof(UNICODE_NULL);
    if (!(GuidString->Buffer = RtlAllocateStringRoutine(GuidString->MaximumLength))) {
        return STATUS_NO_MEMORY;
    }
    swprintf(GuidString->Buffer, GuidFormat, Guid->Data1, Guid->Data2, Guid->Data3, Guid->Data4[0], Guid->Data4[1], Guid->Data4[2], Guid->Data4[3], Guid->Data4[4], Guid->Data4[5], Guid->Data4[6], Guid->Data4[7]);
    return STATUS_SUCCESS;
}


static
int
__cdecl
ScanHexFormat(
    IN const WCHAR* Buffer,
    IN ULONG MaximumLength,
    IN const WCHAR* Format,
    ...)
/*++

Routine Description:

    Scans a source Buffer and places values from that buffer into the parameters
    as specified by Format.

Arguments:

    Buffer -
        Contains the source buffer which is to be scanned.

    MaximumLength -
        Contains the maximum length in characters for which Buffer is searched.
        This implies that Buffer need not be UNICODE_NULL terminated.

    Format -
        Contains the format string which defines both the acceptable string format
        contained in Buffer, and the variable parameters which follow.

Return Value:

    Returns the number of parameters filled if the end of the Buffer is reached,
    else -1 on an error.

--*/
{
    va_list ArgList;
    int     FormatItems;

    va_start(ArgList, Format);
    for (FormatItems = 0;;) {
        switch (*Format) {
        case 0:
            return (MaximumLength && *Buffer) ? -1 : FormatItems;
        case '%':
            Format++;
            if (*Format != '%') {
                ULONG   Number;
                int     Width;
                int     Long;
                PVOID   Pointer;

                for (Long = 0, Width = 0;; Format++) {
                    if ((*Format >= '0') && (*Format <= '9')) {
                        Width = Width * 10 + *Format - '0';
                    } else if (*Format == 'l') {
                        Long++;
                    } else if ((*Format == 'X') || (*Format == 'x')) {
                        break;
                    }
                }
                Format++;
                for (Number = 0; Width--; Buffer++, MaximumLength--) {
                    if (!MaximumLength)
                        return -1;
                    Number *= 16;
                    if ((*Buffer >= '0') && (*Buffer <= '9')) {
                        Number += (*Buffer - '0');
                    } else if ((*Buffer >= 'a') && (*Buffer <= 'f')) {
                        Number += (*Buffer - 'a' + 10);
                    } else if ((*Buffer >= 'A') && (*Buffer <= 'F')) {
                        Number += (*Buffer - 'A' + 10);
                    } else {
                        return -1;
                    }
                }
                Pointer = va_arg(ArgList, PVOID);
                if (Long) {
                    *(PULONG)Pointer = Number;
                } else {
                    *(PUSHORT)Pointer = (USHORT)Number;
                }
                FormatItems++;
                break;
            }
            /* no break */
        default:
            if (!MaximumLength || (*Buffer != *Format)) {
                return -1;
            }
            Buffer++;
            MaximumLength--;
            Format++;
            break;
        }
    }
}


NTSYSAPI
NTSTATUS
NTAPI
RtlGUIDFromString(
    IN PUNICODE_STRING GuidString,
    OUT GUID* Guid
    )
/*++

Routine Description:

    Retrieves a the binary format of a textual GUID presented in the standard
    string version of a GUID: "{xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}".

Arguments:

    GuidString -
        Place from which to retrieve the textual form of the GUID.

    Guid -
        Place in which to put the binary form of the GUID.

Return Value:

    Returns STATUS_SUCCESS if the buffer contained a valid GUID, else
    STATUS_INVALID_PARAMETER if the string was invalid.

--*/
{
    USHORT    Data4[8];
    int       Count;

    RTL_PAGED_CODE();
    if (ScanHexFormat(GuidString->Buffer, GuidString->Length / sizeof(WCHAR), GuidFormat, &Guid->Data1, &Guid->Data2, &Guid->Data3, &Data4[0], &Data4[1], &Data4[2], &Data4[3], &Data4[4], &Data4[5], &Data4[6], &Data4[7]) == -1) {
        return STATUS_INVALID_PARAMETER;
    }
    for (Count = 0; Count < sizeof(Data4)/sizeof(Data4[0]); Count++) {
        Guid->Data4[Count] = (UCHAR)Data4[Count];
    }
    return STATUS_SUCCESS;
}

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