Add basic unicode string support

xtoskrnl/rtl/unicode.cc

@@ -0,0 +1,115 @@
+/**
+ * PROJECT:         ExectOS
+ * COPYRIGHT:       See COPYING.md in the top level directory
+ * FILE:            xtoskrnl/rtl/unicode.cc
+ * DESCRIPTION:     Unicode support
+ * DEVELOPERS:      Aiken Harris <harraiken91@gmail.com>
+ */
+
+#include <xtos.hh>
+
+
+/**
+ * Copies a source Unicode string to a destination Unicode string.
+ *
+ * @param Destination
+ *        Supplies a pointer to the destination string.
+ *
+ * @param Source
+ *        Supplies an optional pointer to the source string. If this parameter is not provided,
+ *        the destination string is effectively emptied.
+ *
+ * @return This routine does not return any value.
+ *
+ * @since XT 1.0
+ */
+XTAPI
+VOID
+RTL::Unicode::CopyString(IN OUT PUNICODE_STRING Destination,
+                         IN PCUNICODE_STRING Source)
+{
+    ULONG Length;
+
+    /* Check if the source string pointer is valid */
+    if(!Source)
+    {
+        /* Source is missing, clear the destination string and return */
+        Destination->Length = 0;
+        return;
+    }
+
+    /* Calculate the length to copy */
+    Length = MIN(Source->Length, Destination->MaximumLength);
+    Destination->Length = Length;
+
+    /* Copy the source string data into the destination buffer */
+    RTL::Memory::CopyMemory(Destination->Buffer, Source->Buffer, Length);
+
+    /* Check if there is enough space left in the buffer to NULL-terminate */
+    if(Destination->Length < Destination->MaximumLength)
+    {
+        /* Append a NULL terminator */
+        Destination->Buffer[Length / sizeof(WCHAR)] = (WCHAR)0;
+    }
+}
+
+/**
+ * Initializes a Unicode string.
+ *
+ * @param Destination
+ *        Supplies a pointer to the UNICODE_STRING structure to be initialized.
+ *
+ * @param Source
+ *        Supplies an optional pointer to a NULL-terminated wide character string.
+ *
+ * @param Truncate
+ *        Specifies whether to truncate the source string to the maximum allowed length.
+ *
+ * @return This routine returns a status code indicating the success or failure of the operation.
+ *
+ * @since XT 1.0
+ */
+XTAPI
+XTSTATUS
+RTL::Unicode::InitializeString(OUT PUNICODE_STRING Destination,
+                               IN PCWSTR Source,
+                               IN BOOLEAN Truncate)
+{
+    ULONG Size;
+
+    /* Check if the source string pointer is valid */
+    if(!Source)
+    {
+        /* Source is missing, initialize the destination as empty string */
+        Destination->Length = 0;
+        Destination->MaximumLength = 0;
+
+        /* Return success */
+        return STATUS_SUCCESS;
+    }
+
+    /* Calculate the size of the string in bytes */
+    Size = RTL::WideString::WideStringLength(Source, 0) * sizeof(WCHAR);
+
+    /* Check if the size exceeds the maximum allowed */
+    if(Size > ((MAXUSHORT & ~1) - sizeof(WCHAR)))
+    {
+        /* Check if truncation is not explicitly forced */
+        if(!Truncate)
+        {
+            /* Return error code */
+            return STATUS_NAME_TOO_LONG;
+        }
+
+        /* Force truncation to the maximum safe length */
+        Size = (MAXUSHORT & ~1) - sizeof(WCHAR);
+    }
+
+    /* Initialize the destination string fields */
+    Destination->Buffer = (PWCHAR)Source;
+    Destination->Length = (USHORT)Size;
+    Destination->MaximumLength = (USHORT)Size + sizeof(WCHAR);
+
+    /* Return success */
+    return STATUS_SUCCESS;
+}