imagehlp/tests: Add initial tests for CheckSumMappedFile.

dlls/imagehlp/modify.c

@@ -89,40 +89,19 @@ PIMAGE_NT_HEADERS WINAPI CheckSumMappedFile(
   LPVOID BaseAddress, DWORD FileLength,
   LPDWORD HeaderSum, LPDWORD CheckSum)
 {
-  IMAGE_DOS_HEADER *dos = (IMAGE_DOS_HEADER *) BaseAddress;
-  PIMAGE_NT_HEADERS32 Header32;
-  PIMAGE_NT_HEADERS64 Header64;
-  DWORD *ChecksumFile;
+  PIMAGE_NT_HEADERS header;
   DWORD CalcSum;
   DWORD HdrSum;
 
-  TRACE("(%p, %d, %p, %p)\n",
-    BaseAddress, FileLength, HeaderSum, CheckSum
-  );
-
-  CalcSum = (DWORD)CalcCheckSum(0,
-				BaseAddress,
-				(FileLength + 1) / sizeof(WORD));
+  TRACE("(%p, %d, %p, %p)\n", BaseAddress, FileLength, HeaderSum, CheckSum);
 
-  if (dos->e_magic != IMAGE_DOS_SIGNATURE)
-    return NULL;
+  CalcSum = CalcCheckSum(0, BaseAddress, (FileLength + 1) / sizeof(WORD));
+  header = RtlImageNtHeader(BaseAddress);
 
-  Header32 = (IMAGE_NT_HEADERS32 *)((char *)dos + dos->e_lfanew);
-
-  if (Header32->Signature != IMAGE_NT_SIGNATURE)
-    return NULL;
-
-  if (Header32->OptionalHeader.Magic == IMAGE_NT_OPTIONAL_HDR32_MAGIC)
-    ChecksumFile = &Header32->OptionalHeader.CheckSum;
-  else if (Header32->OptionalHeader.Magic == IMAGE_NT_OPTIONAL_HDR64_MAGIC)
-  {
-    Header64 = (IMAGE_NT_HEADERS64 *)Header32;
-    ChecksumFile = &Header64->OptionalHeader.CheckSum;
-  }
-  else
+  if (!header)
     return NULL;
 
-  HdrSum = *ChecksumFile;
+  *HeaderSum = HdrSum = header->OptionalHeader.CheckSum;
 
   /* Subtract image checksum from calculated checksum. */
   /* fix low word of checksum */
@@ -149,9 +128,8 @@ PIMAGE_NT_HEADERS WINAPI CheckSumMappedFile(
   CalcSum += FileLength;
 
   *CheckSum = CalcSum;
-  *HeaderSum = *ChecksumFile;
 
-  return (PIMAGE_NT_HEADERS) Header32;
+  return header;
 }
 
 /***********************************************************************