Add helper functions used by the boot protocol during system startup

xtldr/bootutil.c

@@ -0,0 +1,87 @@
+/**
+ * PROJECT:         ExectOS
+ * COPYRIGHT:       See COPYING.md in the top level directory
+ * FILE:            xtldr/bootutil.c
+ * DESCRIPTION:     Helper functions used by the boot protocol during system startup
+ * DEVELOPERS:      Aiken Harris <harraiken91@gmail.com>
+ */
+
+#include <xtldr.h>
+
+
+/**
+ * Checks if a specific option exists in the list of provided boot parameters.
+ *
+ * @param Parameters
+ *        A pointer to the wide-character string containing the boot parameters, separated by spaces.
+ *
+ * @param Needle
+ *        A pointer to the wide-character string representing the kernel option to find.
+ *
+ * @return This routine returns TRUE if the option is found, otherwise FALSE.
+ *
+ * @since XT 1.0
+ */
+XTCDECL
+BOOLEAN
+BlGetBooleanParameter(IN CONST PWCHAR Parameters,
+                      IN CONST PWCHAR Needle)
+{
+    PWCHAR CurrentPosition, TokenEnd, TokenStart;
+    SIZE_T NeedleLength, TokenLength;
+
+    /* Validate input data and ensure the option is not an empty string */
+    if(Parameters == NULL || Needle == NULL || *Needle == L'\0')
+    {
+        /* One of the parameters was invalid */
+        return FALSE;
+    }
+
+    CurrentPosition = Parameters;
+    NeedleLength = RtlWideStringLength(Needle, 0);
+
+    /* Iterate through the entire parameters string */
+    while(*CurrentPosition != L'\0')
+    {
+        /* Skip any leading whitespace to find the start of the token */
+        while(*CurrentPosition == L' ')
+        {
+            CurrentPosition++;
+        }
+
+        /* Check if end of the string has been reached */
+        if(*CurrentPosition == L'\0')
+        {
+            /* End of string reached, no more tokens */
+            break;
+        }
+
+        /* Identify the boundaries of the current token */
+        TokenStart = CurrentPosition;
+        TokenEnd = TokenStart;
+        while(*TokenEnd != L'\0' && *TokenEnd != L' ')
+        {
+            TokenEnd++;
+        }
+
+        /* Calculate the length of the token found */
+        TokenLength = TokenEnd - TokenStart;
+
+         /* Compare the token length */
+        if(TokenLength == NeedleLength)
+        {
+            /* Length matches, compare the strings */
+            if(RtlCompareWideStringInsensitive(TokenStart, Needle, NeedleLength) == 0)
+            {
+                /* A match was found */
+                return TRUE;
+            }
+        }
+
+        /* Move the position past the current token to continue the search */
+        CurrentPosition = TokenEnd;
+    }
+
+    /* No match was found */
+    return FALSE;
+}