Improved robustness of mdfinfo when pointers are null or out of file

Added IDBlock in order to have mdf format version for later improvements. Added .mdf in ui file browser.
sneusse · Dec 2, 2012 · 34f2581 · 34f2581
1 parent 10ee70f
commit 34f2581
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Showing 2 changed files with 77 additions and 54 deletions.
diff --git a/mdfreader.py b/mdfreader.py
@@ -237,6 +237,7 @@ class mdfinfo( dict):
 
     def __init__( self, fileName = None ):
         self.fileName = fileName
+        self['IDBlock'] = {} # Identifier Block
         self['HDBlock'] = {} # Header Block
         self['DGBlock']= {} # Data Group Block
         self['CGBlock'] = {} # Channel Group Block
@@ -257,13 +258,20 @@ def readinfo( self, fileName = None ):
         except IOError:
             print('Can not find file'+self.fileName)
             raise
-
+        # read Identifier block
+        #self['IDBlock'] = self.mdfblockread( self.blockformats( 'IDFormat' ), fid, 0)
+        fid.seek(24)
+        self['IDBlock']['ByteOrder']=unpack( '<H', fid.read( 2 ) )
+        self['IDBlock']['FloatingPointFormat']=unpack( '<H', fid.read( 2 ) )
+        self['IDBlock']['VersionNumber']=unpack( '<H', fid.read( 2 ) )
+        self['IDBlock']['VersionNumber']=self['IDBlock']['VersionNumber'][0]
+        self['IDBlock']['CodePageNumber']=unpack( '<H', fid.read( 2 ) )
+        self['IDBlock']['CodePageNumber']=self['IDBlock']['CodePageNumber'][0]
+
         ### Read header block (HDBlock) information
-        # Set file pointer to start of HDBlock
-        HDpointer = 64
-        # Read Header block info into structure
-        self['HDBlock'] = self.mdfblockread( self.blockformats( 'HDFormat' ), fid, HDpointer )
-
+        # Read Header block info into structure, HD pointer at 64 as mentioned in specification
+        self['HDBlock'] = self.mdfblockread( self.blockformats( 'HDFormat' ), fid, 64 )
+
         ### Read text block (TXBlock) information
         self['HDBlock']['TXBlock'] = self.mdfblockread( self.blockformats( 'TXFormat' ), fid, self['HDBlock']['pointerToTXBlock'] )
 
@@ -537,52 +545,11 @@ def blockformats( block ):
         UINT32 = '<I'
         UINT64 = '<Q'
 
-        if block == 'HDFormat':
-            formats = ( 
-                ( CHAR , 2, 'BlockType' ),
-                ( UINT16, 1, 'BlockSize' ),
-                ( LINK, 1, 'pointerToFirstDGBlock' ),
-                ( LINK, 1, 'pointerToTXBlock' ),
-                ( LINK, 1, 'pointerToPRBlock' ),
-                ( UINT16, 1, 'numberOfDataGroups' ),
-                ( CHAR, 10, 'Date' ),
-                ( CHAR, 8, 'Time' ),
-                ( CHAR, 32, 'Author' ),
-                ( CHAR, 32, 'Organization' ),
-                ( CHAR, 32, 'ProjectName' ),
-                ( CHAR, 32, 'Vehicle' ) )
-        elif block == 'TXFormat':
+        if block == 'TXFormat':
             formats = ( 
                 ( CHAR, 2, 'BlockType' ),
                 ( UINT16, 1, 'BlockSize' ),
                 ( CHAR, 'Var', 'Text' ) )
-        elif block == 'PRFormat':
-            formats = ( 
-                ( CHAR, 2, 'BlockType' ),
-                ( UINT16, 1, 'BlockSize' ),
-                ( CHAR, 'Var', 'PRData' ) )
-        elif block == 'DGFormat':
-            formats = ( 
-                ( CHAR, 2, 'BlockType' ),
-                ( UINT16, 1, 'BlockSize' ), #All DGBlocks Size
-                ( LINK , 1, 'pointerToNextDGBlock' ),
-                ( LINK , 1, 'pointerToNextCGBlock' ),
-                ( LINK, 1, 'reserved' ),
-                ( LINK, 1, 'pointerToDataRecords' ),
-                ( UINT16, 1, 'numberOfChannelGroups' ),
-                ( UINT16, 1, 'numberOfRecordIDs' ) )
-        elif block == 'CGFormat':
-            formats = ( 
-                ( CHAR, 2, 'BlockType' ),
-                ( UINT16, 1, 'BlockSize' ),
-                ( LINK, 1, 'pointerToNextCGBlock' ),
-                ( LINK, 1, 'pointerToFirstCNBlock' ),
-                ( LINK, 1, 'pointerToChannelGroupCommentText' ),
-                ( UINT16, 1, 'recordID' ),
-                ( UINT16, 1, 'numberOfChannels' ),
-                ( UINT16, 1, 'dataRecordSize' ),
-                ( UINT32, 1, 'numberOfRecords' ) )
-                # last one missing
         elif block == 'CNFormat':
             formats = ( 
                 ( CHAR, 2, 'BlockType' ),
@@ -652,6 +619,56 @@ def blockformats( block ):
                 ( REAL, 1, 'lowerRange' ),
                 ( REAL, 1, 'upperRange' ),
                 ( LINK, 1, 'pointerToTXBlock' ) )
+        elif block == 'PRFormat':
+            formats = ( 
+                ( CHAR, 2, 'BlockType' ),
+                ( UINT16, 1, 'BlockSize' ),
+                ( CHAR, 'Var', 'PRData' ) )
+        elif block == 'CGFormat':
+            formats = ( 
+                ( CHAR, 2, 'BlockType' ),
+                ( UINT16, 1, 'BlockSize' ),
+                ( LINK, 1, 'pointerToNextCGBlock' ),
+                ( LINK, 1, 'pointerToFirstCNBlock' ),
+                ( LINK, 1, 'pointerToChannelGroupCommentText' ),
+                ( UINT16, 1, 'recordID' ),
+                ( UINT16, 1, 'numberOfChannels' ),
+                ( UINT16, 1, 'dataRecordSize' ),
+                ( UINT32, 1, 'numberOfRecords' ) )
+                # last one missing
+        elif block == 'DGFormat':
+            formats = ( 
+                ( CHAR, 2, 'BlockType' ),
+                ( UINT16, 1, 'BlockSize' ), #All DGBlocks Size
+                ( LINK , 1, 'pointerToNextDGBlock' ),
+                ( LINK , 1, 'pointerToNextCGBlock' ),
+                ( LINK, 1, 'reserved' ),
+                ( LINK, 1, 'pointerToDataRecords' ),
+                ( UINT16, 1, 'numberOfChannelGroups' ),
+                ( UINT16, 1, 'numberOfRecordIDs' ) )
+        elif block == 'HDFormat':
+            formats = ( 
+                ( CHAR , 2, 'BlockType' ),
+                ( UINT16, 1, 'BlockSize' ),
+                ( LINK, 1, 'pointerToFirstDGBlock' ),
+                ( LINK, 1, 'pointerToTXBlock' ),
+                ( LINK, 1, 'pointerToPRBlock' ),
+                ( UINT16, 1, 'numberOfDataGroups' ),
+                ( CHAR, 10, 'Date' ),
+                ( CHAR, 8, 'Time' ),
+                ( CHAR, 32, 'Author' ),
+                ( CHAR, 32, 'Organization' ),
+                ( CHAR, 32, 'ProjectName' ),
+                ( CHAR, 32, 'Vehicle' ) )
+        elif block== 'IDFormat':
+            formats = ( 
+                ( CHAR, 8, 'FileID' ),
+                ( CHAR, 8, 'FormatID' ),
+                ( CHAR, 8, 'ProgramID' ),
+                ( UINT16, 1, 'ByteOrder' ),
+                ( UINT16, 1, 'FloatingPointFormat' ),
+                ( UINT16, 1, 'VersionNumber' ),
+                ( UINT16, 1, 'CodePageNumber' ))
         else:
             print( 'Block format name error ' )
         return formats
@@ -672,9 +689,9 @@ def mdfblockread( blockFormat, fid, pointer ):
         #
         # Example function call is:
         # Block=mdfblockread(blockFormat, 1, 413)
-        fid.seek( pointer )
         Block = {}
-        if pointer != 0:
+        if pointer != 0 and not pointer == None:
+            fid.seek( pointer )
             # Extract parameters
             for field in range( len( blockFormat ) ):
                 fieldTuple = blockFormat[field]
@@ -684,13 +701,19 @@ def mdfblockread( blockFormat, fid, pointer ):
                 if fieldFormat == '<c': # Char
                     if fieldNumber != 'Var':
                         value = fid.read( fieldNumber )
-                    elif Block['BlockSize'] - 4 > 0:
+                    elif Block['BlockSize'] and Block['BlockSize'] - 4 > 0:
                         value = fid.read( Block['BlockSize'] - 4 )
+                    elif not Block['BlockSize'] :
+                        value=''
                     Block[fieldName] = value.decode('latin1', 'replace').replace('\x00', '') # decode
                 else: # numeric
                     formatSize = calcsize( fieldFormat )
-                    value = unpack( fieldFormat, fid.read( formatSize * fieldNumber ) )
-                    Block[fieldName] = value[0]
+                    number=fid.read( formatSize * fieldNumber ) 
+                    if number:
+                        value = unpack( fieldFormat, number)
+                        Block[fieldName] = value[0]
+                    else:
+                        Block[fieldName] = None
             return Block
 
 

diff --git a/mdfreaderui.py b/mdfreaderui.py
@@ -47,7 +47,7 @@ def on_browse_clicked(self):
         """
         Will open a dialog to browse for files
         """
-        self.fileNames=QFileDialog.getOpenFileNames(self, "Select Measurement Files",filter=("MDF file (*.dat)"))
+        self.fileNames=QFileDialog.getOpenFileNames(self, "Select Measurement Files",filter=("MDF file (*.dat *.mdf)"))
         if not len(self.fileNames)==0:
             self.FileList.addItems(self.fileNames)
             self.mdfinfoClass.__init__()