From a0f359bcf7531f55196d33dc204abf22cc04c955 Mon Sep 17 00:00:00 2001
From: belliash <belliash@codingworkshop.eu.org>
Date: Mon, 26 Sep 2022 17:26:00 +0200
Subject: [PATCH] Implement RtlWideStringConcatenate() routine

---
 sdk/xtdk/rtlfuncs.h    |  6 +++++
 xtoskrnl/rtl/widestr.c | 59 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 65 insertions(+)

diff --git a/sdk/xtdk/rtlfuncs.h b/sdk/xtdk/rtlfuncs.h
index e74d710..f53c22c 100644
--- a/sdk/xtdk/rtlfuncs.h
+++ b/sdk/xtdk/rtlfuncs.h
@@ -73,6 +73,12 @@ RtlWideStringCompare(IN CONST PWCHAR String1,
                      IN CONST PWCHAR String2,
                      IN CONST ULONG Length);
 
+XTCDECL
+PWCHAR
+RtlWideStringConcatenate(PWCHAR Destination,
+                         PWCHAR Source,
+                         SIZE_T Count);
+
 XTCDECL
 SIZE_T
 RtlWideStringLength(IN CONST PWCHAR String,
diff --git a/xtoskrnl/rtl/widestr.c b/xtoskrnl/rtl/widestr.c
index b75b19d..467f4ff 100644
--- a/xtoskrnl/rtl/widestr.c
+++ b/xtoskrnl/rtl/widestr.c
@@ -61,6 +61,65 @@ RtlWideStringCompare(IN CONST PWCHAR String1,
     return 0;
 }
 
+/**
+ * Appends a copy of the source wide string to the end of the destination wide string.
+ *
+ * @param Destination
+ *        Supplies a pointer to the null-terminated wide string to append to.
+ *
+ * @param Source
+ *        Supplies a pointer to the null-terminated wide string to copy from.
+ *
+ * @param Count
+ *        Sets a maximum number of wide characters to copy. If no limit set, appends whole wide string.
+ *
+ * @return This routine returns a copy of a destination wide string.
+ *
+ * @since XT 1.0
+ */
+XTCDECL
+PWCHAR
+RtlWideStringConcatenate(PWCHAR Destination,
+                         PWCHAR Source,
+                         SIZE_T Count)
+{
+    PWCHAR DestString = Destination;
+
+    /* Go to the end of destination wide string */
+    while(*Destination)
+    {
+        Destination++;
+    }
+
+    /* Check if copy limit set */
+    if(Count > 0)
+    {
+        /* Copy character-by-character */
+        do
+        {
+            /* Check if NULL terminated character found */
+            if((*Destination = *Source++) == '\0')
+            {
+                /* Break on '\0' character */
+                break;
+            }
+            Destination++;
+        }
+        while(--Count != 0);
+
+        /* Add NULL termination character to the end of destination wide string */
+        *Destination = '\0';
+    }
+    else
+    {
+        /* No limit set, copy all wide characters */
+        while((*Destination++ = *Source++) != 0);
+    }
+
+    /* Return copy of the destination wide string */
+    return DestString;
+}
+
 /**
  * Calculates the length of a given wide string.
  *