From 55b6c66d7aa6daa4030ff3c33d1a186c6b348e2e Mon Sep 17 00:00:00 2001
From: Alex Ionescu <aionescu@gmail.com>
Date: Thu, 21 Jan 2016 15:47:14 +0000
Subject: [PATCH] [BOOTLIB]: Cleanup, less magic.

svn path=/trunk/; revision=70633
---
 reactos/boot/environ/include/bl.h     | 14 +++++++
 reactos/boot/environ/lib/misc/image.c | 60 ++++-----------------------
 reactos/boot/environ/lib/misc/util.c  | 58 ++++++++++++++++++++++++++
 3 files changed, 81 insertions(+), 51 deletions(-)

diff --git a/reactos/boot/environ/include/bl.h b/reactos/boot/environ/include/bl.h
index 6488e308ce1..923a28338b7 100644
--- a/reactos/boot/environ/include/bl.h
+++ b/reactos/boot/environ/include/bl.h
@@ -155,6 +155,12 @@ DEFINE_GUID(BadMemoryGuid, 0x54B8275B, 0xD431, 0x473F, 0xAC, 0xFB, 0xE5, 0x36, 0
 #define BL_LOAD_PE_IMG_CHECK_SUBSYSTEM                  0x80
 #define BL_LOAD_PE_IMG_CHECK_FORCED_INTEGRITY           0x200
 
+#define BL_UTL_CHECKSUM_COMPLEMENT                      0x10000
+#define BL_UTL_CHECKSUM_ROTATE                          0x20000
+#define BL_UTL_CHECKSUM_NEGATE                          0x40000
+#define BL_UTL_CHECKSUM_UCHAR_BUFFER                    0x01
+#define BL_UTL_CHECKSUM_USHORT_BUFFER                   0x02
+
 /* ENUMERATIONS **************************************************************/
 
 typedef enum _BL_COLOR
@@ -1620,6 +1626,14 @@ BlUtlRegisterProgressRoutine (
     VOID
     );
 
+ULONG
+BlUtlCheckSum (
+    _In_ ULONG PartialSum,
+    _In_ PUCHAR Buffer,
+    _In_ ULONG Length,
+    _In_ ULONG Flags
+    );
+
 NTSTATUS
 BlGetApplicationBaseAndSize (
     _Out_ PVOID* ImageBase,
diff --git a/reactos/boot/environ/lib/misc/image.c b/reactos/boot/environ/lib/misc/image.c
index c155930d41c..a734bcc4a70 100644
--- a/reactos/boot/environ/lib/misc/image.c
+++ b/reactos/boot/environ/lib/misc/image.c
@@ -651,54 +651,6 @@ BlImgUnLoadImage (
     return BlImgUnallocateImageBuffer(ImageBase, ImageSize, ImageFlags);
 }
 
-unsigned int  BlUtlCheckSum(unsigned int PartialSum, PUCHAR Source, unsigned int Length, unsigned int Flags)
-{
-    unsigned int Type; // eax@1
-    int Type1; // eax@1
-    unsigned int AlignedLength; // ebx@3
-    unsigned int i; // ebx@21 MAPDST
-
-    Type = Flags & 3;
-    Type1 = Type - 1;
-    if (Type1)
-    {
-        if (Type1 == 1)
-        {
-            PartialSum = (unsigned __int16)PartialSum;
-            AlignedLength = Length & ~1;
-            if (Length & ~1)
-            {
-                i = 0;
-                do
-                {
-                    PartialSum += *(unsigned __int16 *)&Source[i];
-                    if (Flags & 0x10000)
-                        PartialSum = (unsigned __int16)((PartialSum >> 16) + PartialSum);
-                    i += 2;
-                } while (i < AlignedLength);
-            }
-
-            if (Length != AlignedLength)
-            {
-                PartialSum += (unsigned __int8)Source[AlignedLength];
-                if (Flags & 0x10000)
-                    PartialSum = (unsigned __int16)((PartialSum >> 16) + PartialSum);
-            }
-            if (Flags & 0x40000)
-                return ~PartialSum;
-            PartialSum = (unsigned __int16)PartialSum;
-        }
-    }
-    else
-    {
-        EfiPrintf(L"checksum type not supported\r\n");
-    }
-
-    if (Flags & 0x40000)
-        return ~PartialSum;
-    return PartialSum;
-}
-
 NTSTATUS
 ImgpLoadPEImage (
     _In_ PBL_IMG_FILE ImageFile,
@@ -921,7 +873,11 @@ ImgpLoadPEImage (
     NtHeaders->OptionalHeader.CheckSum = 0;
 
     /* Calculate the checksum of the header, and restore the original one */
-    PartialSum = BlUtlCheckSum(0, VirtualAddress, HeaderSize, 0x10002);
+    PartialSum = BlUtlCheckSum(0,
+                               VirtualAddress,
+                               HeaderSize,
+                               BL_UTL_CHECKSUM_COMPLEMENT |
+                               BL_UTL_CHECKSUM_USHORT_BUFFER);
     NtHeaders->OptionalHeader.CheckSum = CheckSum;
 
     /* Record our current position (right after the headers) */
@@ -1037,7 +993,8 @@ ImgpLoadPEImage (
                 PartialSum = BlUtlCheckSum(PartialSum,
                                            (PUCHAR)SectionStart,
                                            AlignSize,
-                                           0x10002);
+                                           BL_UTL_CHECKSUM_COMPLEMENT |
+                                           BL_UTL_CHECKSUM_USHORT_BUFFER);
             }
         }
 
@@ -1114,7 +1071,8 @@ ImgpLoadPEImage (
             PartialSum = BlUtlCheckSum(PartialSum,
                                        LocalBuffer,
                                        BytesRead,
-                                       0x10002);
+                                       BL_UTL_CHECKSUM_COMPLEMENT |
+                                       BL_UTL_CHECKSUM_USHORT_BUFFER);
         }
 
         /* Finally, calculate the final checksum and compare it */
diff --git a/reactos/boot/environ/lib/misc/util.c b/reactos/boot/environ/lib/misc/util.c
index bd37bebe8bb..3e152d3dc07 100644
--- a/reactos/boot/environ/lib/misc/util.c
+++ b/reactos/boot/environ/lib/misc/util.c
@@ -720,3 +720,61 @@ Quickie:
     return Status;
 }
 
+ULONG
+BlUtlCheckSum (
+    _In_ ULONG PartialSum,
+    _In_ PUCHAR Buffer,
+    _In_ ULONG Length,
+    _In_ ULONG Flags
+    )
+{
+    ULONG i;
+
+    if (Flags & BL_UTL_CHECKSUM_UCHAR_BUFFER)
+    {
+        EfiPrintf(L"Not supported\r\n");
+        return 0;
+    }
+    else if (Flags & BL_UTL_CHECKSUM_USHORT_BUFFER)
+    {
+        PartialSum = (unsigned __int16)PartialSum;
+        Length &= ~1;
+
+        for (i = 0; i < Length; i += 2)
+        {
+            PartialSum += *(unsigned __int16 *)&Buffer[i];
+            if (Flags & BL_UTL_CHECKSUM_COMPLEMENT)
+            {
+                PartialSum = (unsigned __int16)((PartialSum >> 16) + PartialSum);
+            }
+        }
+
+        if (Length != Length)
+        {
+            PartialSum += (unsigned __int8)Buffer[Length];
+            if (Flags & BL_UTL_CHECKSUM_COMPLEMENT)
+            {
+                PartialSum = (unsigned __int16)((PartialSum >> 16) + PartialSum);
+            }
+        }
+
+        if (Flags & BL_UTL_CHECKSUM_NEGATE)
+        {
+            return ~PartialSum;
+        }
+
+        PartialSum = (unsigned __int16)PartialSum;
+    }
+    else
+    {
+        /* Invalid mode */
+        return 0;
+    }
+
+    if (Flags & BL_UTL_CHECKSUM_NEGATE)
+    {
+        return ~PartialSum;
+    }
+
+    return PartialSum;
+}