[PATCH v2] MdeModulePkg/Browser: Enhance the logic when getting value from AltResp

[Dandan Bi <dandan.bi@intel.com>]

This patch is to enhance SetupBrowser to handle following two cases:
1. When searching BlockName in AltResp, the hex digits of related BlockName
   in AltResp may be in uppercase.
2. When converting the Value in AltResp to HiiValue, the length of value
   string is bigger than the length of StorageWidth of the question.

Notes:
V2:
- Add some comments to make the logic clear.

Cc: Liming Gao <liming.gao@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Dandan Bi <dandan.bi@intel.com>
Reviewed-by: Eric Dong <eric.dong@intel.com>
---
 MdeModulePkg/Universal/SetupBrowserDxe/Setup.c | 61 +++++++++++++++-----------
 1 file changed, 35 insertions(+), 26 deletions(-)

diff --git a/MdeModulePkg/Universal/SetupBrowserDxe/Setup.c b/MdeModulePkg/Universal/SetupBrowserDxe/Setup.c
index 66c4313..cd3c8cc 100644
--- a/MdeModulePkg/Universal/SetupBrowserDxe/Setup.c
+++ b/MdeModulePkg/Universal/SetupBrowserDxe/Setup.c
@@ -1427,44 +1427,48 @@ BufferToValue (
   }
   TempChar = *StringPtr;
   *StringPtr = L'\0';
 
   LengthStr = StrLen (Value);
+
+  //
+  // Value points to a Unicode hexadecimal string, we need to convert the string to the value with CHAR16/UINT8...type.
+  // When generating the Value string, we follow this rule: 1 byte -> 2 Unicode characters (for string: 2 byte(CHAR16) ->4 Unicode characters).
+  // So the maximum value string length of a question is : Question->StorageWidth * 2.
+  // If the value string length > Question->StorageWidth * 2, only set the string length as Question->StorageWidth * 2, then convert.
+  //
+  if (LengthStr > (UINTN) Question->StorageWidth * 2) {
+    Length = (UINTN) Question->StorageWidth * 2;
+  } else {
+    Length = LengthStr;
+  }
+
   Status    = EFI_SUCCESS;
   if (!IsBufferStorage && IsString) {
     //
     // Convert Config String to Unicode String, e.g "0041004200430044" => "ABCD"
     // Add string tail char L'\0' into Length
     //
-    Length    = Question->StorageWidth + sizeof (CHAR16);
-    if (Length < ((LengthStr / 4 + 1) * 2)) {
-      Status = EFI_BUFFER_TOO_SMALL;
-    } else {
-      DstBuf = (CHAR16 *) Dst;
-      ZeroMem (TemStr, sizeof (TemStr));
-      for (Index = 0; Index < LengthStr; Index += 4) {
-        StrnCpyS (TemStr, sizeof (TemStr) / sizeof (CHAR16), Value + Index, 4);
-        DstBuf[Index/4] = (CHAR16) StrHexToUint64 (TemStr);
-      }
-      //
-      // Add tailing L'\0' character
-      //
-      DstBuf[Index/4] = L'\0';
+    DstBuf = (CHAR16 *) Dst;
+    ZeroMem (TemStr, sizeof (TemStr));
+    for (Index = 0; Index < Length; Index += 4) {
+      StrnCpyS (TemStr, sizeof (TemStr) / sizeof (CHAR16), Value + Index, 4);
+      DstBuf[Index/4] = (CHAR16) StrHexToUint64 (TemStr);
     }
+    //
+    // Add tailing L'\0' character
+    //
+    DstBuf[Index/4] = L'\0';
   } else {
-    if (Question->StorageWidth < ((LengthStr + 1) / 2)) {
-      Status = EFI_BUFFER_TOO_SMALL;
-    } else {
-      ZeroMem (TemStr, sizeof (TemStr));
-      for (Index = 0; Index < LengthStr; Index ++) {
-        TemStr[0] = Value[LengthStr - Index - 1];
-        DigitUint8 = (UINT8) StrHexToUint64 (TemStr);
-        if ((Index & 1) == 0) {
-          Dst [Index/2] = DigitUint8;
-        } else {
-          Dst [Index/2] = (UINT8) ((DigitUint8 << 4) + Dst [Index/2]);
-        }
+    ZeroMem (TemStr, sizeof (TemStr));
+    for (Index = 0; Index < Length; Index ++) {
+      TemStr[0] = Value[LengthStr - Index - 1];
+      DigitUint8 = (UINT8) StrHexToUint64 (TemStr);
+      if ((Index & 1) == 0) {
+        Dst [Index/2] = DigitUint8;
+      } else {
+        Dst [Index/2] = (UINT8) ((DigitUint8 << 4) + Dst [Index/2]);
       }
     }
   }
 
   *StringPtr = TempChar;
@@ -3755,10 +3759,15 @@ GetOffsetFromConfigResp (
   //
   // Type is EFI_HII_VARSTORE_EFI_VARIABLE or EFI_HII_VARSTORE_EFI_VARIABLE_BUFFER
   //
 
   //
+  // Convert all hex digits in ConfigResp to lower case before searching.
+  //
+  HiiToLower (ConfigResp);
+
+  //
   // 1. Directly use Question->BlockName to find.
   //
   RequestElement = StrStr (ConfigResp, Question->BlockName);
   if (RequestElement != NULL) {
     //
-- 
1.9.5.msysgit.1