[Patch] BaseTools: Enhance tool to generate EFI_HII_IIBT_DUPLICATE image block

[Yonghong Zhu <yonghong.zhu@intel.com>]

When *.IDF file contains multiple definitions of image which point to the
same image, current build tool generates multiple image blocks which
contain the same image content.
This patch enhance tool to generate EFI_HII_IIBT_DUPLICATE image blocks
for non-first images for such case, to save the HII package size.

Fixes: https://bugzilla.tianocore.org/show_bug.cgi?id=145

Cc: Liming Gao <liming.gao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Yonghong Zhu <yonghong.zhu@intel.com>
---
 BaseTools/Source/Python/AutoGen/GenC.py | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/BaseTools/Source/Python/AutoGen/GenC.py b/BaseTools/Source/Python/AutoGen/GenC.py
index 8089e3a..de6eb0e 100644
--- a/BaseTools/Source/Python/AutoGen/GenC.py
+++ b/BaseTools/Source/Python/AutoGen/GenC.py
@@ -1637,10 +1637,11 @@ def CreateIdfFileCode(Info, AutoGenC, StringH, IdfGenCFlag, IdfGenBinBuffer):
             PaletteInfoOffset = 0
             ImageBuffer = pack('x')
             PaletteBuffer = pack('x')
             BufferStr = ''
             PaletteStr = ''
+            FileDict = {}
             for Idf in ImageFiles.ImageFilesDict:
                 if ImageFiles.ImageFilesDict[Idf]:
                     for FileObj in ImageFiles.ImageFilesDict[Idf]:
                         for sourcefile in Info.SourceFileList:
                             if FileObj.FileName == sourcefile.File:
@@ -1661,10 +1662,23 @@ def CreateIdfFileCode(Info, AutoGenC, StringH, IdfGenCFlag, IdfGenBinBuffer):
                             if (ValueStartPtr - len(DEFINE_STR + ID)) <= 0:
                                 Line = DEFINE_STR + ' ' + ID + ' ' + DecToHexStr(Index, 4) + '\n'
                             else:
                                 Line = DEFINE_STR + ' ' + ID + ' ' * (ValueStartPtr - len(DEFINE_STR + ID)) + DecToHexStr(Index, 4) + '\n'
 
+                            if File not in FileDict:
+                                FileDict[File] = Index
+                            else:
+                                DuplicateBlock = pack('B', EFI_HII_IIBT_DUPLICATE)
+                                DuplicateBlock += pack('H', FileDict[File])
+                                ImageBuffer += DuplicateBlock
+                                BufferStr = WriteLine(BufferStr, '// %s: %s: %s' % (DecToHexStr(Index, 4), ID, DecToHexStr(Index, 4)))
+                                TempBufferList = AscToHexList(DuplicateBlock)
+                                BufferStr = WriteLine(BufferStr, CreateArrayItem(TempBufferList, 16) + '\n')
+                                StringH.Append(Line)
+                                Index += 1
+                                continue
+
                             TmpFile = open(File.Path, 'rb')
                             Buffer = TmpFile.read()
                             TmpFile.close()
                             if File.Ext.upper() == '.PNG':
                                 TempBuffer = pack('B', EFI_HII_IIBT_IMAGE_PNG)
-- 
2.6.1.windows.1