From b57ee630fd8ee9e1c2660fef90c0f5bd0edfff65 Mon Sep 17 00:00:00 2001
From: Rafal Kupiec <belliash@codingworkshop.eu.org>
Date: Sat, 9 Dec 2023 20:17:08 +0100
Subject: [PATCH] Implement RtlTrimLeftString(), RtlTrimRightString() and
 RtlTrimString() routines

---
 sdk/xtdk/rtlfuncs.h    | 12 +++++++
 xtoskrnl/rtl/string.c  | 80 ++++++++++++++++++++++++++++++++++++++++++
 xtoskrnl/xtoskrnl.spec |  3 ++
 3 files changed, 95 insertions(+)

diff --git a/sdk/xtdk/rtlfuncs.h b/sdk/xtdk/rtlfuncs.h
index 4f275ad..e435a7b 100644
--- a/sdk/xtdk/rtlfuncs.h
+++ b/sdk/xtdk/rtlfuncs.h
@@ -131,6 +131,18 @@ RtlTokenizeWideString(IN PWCHAR String,
                       IN CONST PWCHAR Delimiter,
                       IN OUT PWCHAR *SavePtr);
 
+XTCDECL
+PCHAR
+RtlTrimLeftString(IN CONST PCHAR String);
+
+XTCDECL
+PCHAR
+RtlTrimRightString(IN CONST PCHAR String);
+
+XTCDECL
+PCHAR
+RtlTrimString(IN CONST PCHAR String);
+
 XTCDECL
 SIZE_T
 RtlWideStringLength(IN CONST PWCHAR String,
diff --git a/xtoskrnl/rtl/string.c b/xtoskrnl/rtl/string.c
index 3716d6b..c277e44 100644
--- a/xtoskrnl/rtl/string.c
+++ b/xtoskrnl/rtl/string.c
@@ -218,3 +218,83 @@ RtlStringToWideString(OUT PWCHAR Destination,
 
     return Length - Count;
 }
+
+/**
+ * Removes certain characters from a beginning of the string.
+ *
+ * @param String
+ *        Pointer to the null-terminated string to be trimmed.
+ *
+ * @return This routine returns a pointer to the left-trimmed string.
+ *
+ * @since XT 1.0
+ */
+XTCDECL
+PCHAR
+RtlTrimLeftString(IN CONST PCHAR String)
+{
+    PCHAR Start;
+
+    /* Initialize pointer */
+    Start = String;
+
+    /* Skip all leading whitespaces */
+    while(*Start == ' ' || *Start == '\n' || *Start == '\t' || *Start == '\r' || *Start == '\v' || *Start == '\f')
+    {
+        /* Advance to the next character */
+        Start++;
+    }
+
+    /* Return left-trimmed string */
+    return Start;
+}
+
+/**
+ * Removes certain characters from the end of the string.
+ *
+ * @param String
+ *        Pointer to the null-terminated string to be trimmed.
+ *
+ * @return This routine returns a pointer to the right-trimmed string.
+ *
+ * @since XT 1.0
+ */
+XTCDECL
+PCHAR
+RtlTrimRightString(IN CONST PCHAR String)
+{
+    PCHAR End;
+
+    /* Find end of the string */
+    End = String + RtlStringLength(String, 0);
+
+    /* Skip all trailing whitespaces */
+    while((End != String) && (*End == ' ' || *End == '\n' || *End == '\t' || *End == '\r' || *End == '\v' || *End == '\f'))
+    {
+        /* Move to the previous character */
+        End--;
+    }
+
+    /* Terminate the string */
+    *End = 0;
+
+    /* Return right-trimmed string */
+    return String;
+}
+
+/**
+ * Removes certain characters from the beginning and the end of the string.
+ *
+ * @param String
+ *        Pointer to the null-terminated string to be trimmed.
+ *
+ * @return This routine returns a pointer to the trimmed string.
+ *
+ * @since XT 1.0
+ */
+XTCDECL
+PCHAR
+RtlTrimString(IN CONST PCHAR String)
+{
+    return RtlTrimLeftString(RtlTrimRightString(String));
+}
diff --git a/xtoskrnl/xtoskrnl.spec b/xtoskrnl/xtoskrnl.spec
index 0864d76..cb5869c 100644
--- a/xtoskrnl/xtoskrnl.spec
+++ b/xtoskrnl/xtoskrnl.spec
@@ -40,6 +40,9 @@
 @ cdecl RtlCompareWideStringInsensitive(wstr wstr long)
 @ cdecl RtlConcatenateWideString(wstr wstr long)
 @ cdecl RtlTokenizeWideString(wstr wstr wstr)
+@ cdecl RtlTrimLeftString(str)
+@ cdecl RtlTrimRightString(str)
+@ cdecl RtlTrimString(str)
 @ cdecl RtlWideStringLength(wstr long)
 @ stdcall RtlWriteRegisterByte(ptr long)
 @ stdcall RtlWriteRegisterLong(ptr long)