[SDK:RTL] Add RtlInitUnicodeString() and RtlGUIDFromString()

SDK/RTL/string.c

@@ -0,0 +1,63 @@
+/*++
+
+Copyright (c) 2024, Quinn Stephens.
+Provided under the BSD 3-Clause license.
+
+Module Name:
+
+   string.c
+
+Abstract:
+
+   Provides RTL string routines.
+
+--*/
+
+#include <ntrtl.h>
+#include <wchar.h>
+
+VOID
+NTAPI
+RtlInitUnicodeString (
+   OUT PUNICODE_STRING Destination,
+   IN PCWSTR Source
+   )
+
+/*++
+
+Routine Description:
+
+    Initializes a unicode string structure with an existing string,
+    which may be NULL to initialize an empty unicode string structure.
+
+Arguments:
+
+    Destination - A pointer to the unicode string structure.
+
+    Source - Optionally, a pointer to a null-terminated string to initialize
+        the unicode string structure with.
+
+Return Value:
+
+    None.
+
+--*/
+
+{
+    ULONG Length;
+
+    Destination->Buffer = (PWSTR)Source;
+    if (Source == NULL) {
+        Destination->Length = 0;
+        Destination->MaximumLength = 0;
+        return;
+    }
+
+    Length = wcslen(Source) * sizeof(WCHAR);
+    if (Length >= MAX_USTRING) {
+        Length = MAX_USTRING - sizeof(UNICODE_NULL);
+    }
+
+    Destination->Length = (USHORT)Length;
+    Destination->MaximumLength = (USHORT)(Length + sizeof(UNICODE_NULL));
+}