- Add some extra methods to DataReader which obtain a new reader with additional restrictions.

- Use new methods to simplify a few places in DwarfFile.



git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@39918 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/apps/debugger/dwarf/DataReader.h

@@ -36,6 +36,21 @@ public:
 		fOverflow = false;
 	}
 
+	DataReader RestrictedReader()
+	{
+		return *this;
+	}
+
+	DataReader RestrictedReader(off_t maxLength)
+	{
+		return DataReader(fData, maxLength, fAddressSize);
+	}
+
+	DataReader RestrictedReader(off_t relativeOffset, off_t maxLength)
+	{
+		return DataReader(fData + relativeOffset, maxLength, fAddressSize);
+	}
+
 	bool HasData() const
 	{
 		return fSize > 0;

src/apps/debugger/dwarf/DwarfFile.cpp

@@ -672,8 +672,10 @@ DwarfFile::UnwindCallFrame(CompilationUnit* unit,
 				if (error != B_OK)
 					return error;
 
+				DataReader restrictedReader =
+					dataReader.RestrictedReader(remaining);
 				error = _ParseFrameInfoInstructions(unit, context,
-					dataReader.Offset(), remaining);
+					restrictedReader);
 				if (error != B_OK)
 					return error;
 
@@ -1604,22 +1606,15 @@ DwarfFile::_ParseCIE(CompilationUnit* unit, CfaContext& context,
 	if (remaining < 0)
 		return B_BAD_DATA;
 
-	return _ParseFrameInfoInstructions(unit, context,
-		cieOffset + dataReader.Offset(), remaining);
+	DataReader restrictedReader = dataReader.RestrictedReader(remaining);
+	return _ParseFrameInfoInstructions(unit, context, restrictedReader);
 }
 
 
 status_t
 DwarfFile::_ParseFrameInfoInstructions(CompilationUnit* unit,
-	CfaContext& context, off_t instructionOffset, off_t instructionSize)
+	CfaContext& context, DataReader& dataReader)
 {
-	if (instructionSize <= 0)
-		return B_OK;
-
-	DataReader dataReader(
-		(uint8*)fDebugFrameSection->Data() + instructionOffset,
-		instructionSize, unit->AddressSize());
-
 	while (dataReader.BytesRemaining() > 0) {
 		TRACE_CFI("    [%2lld]", dataReader.BytesRemaining());
 

src/apps/debugger/dwarf/DwarfFile.h

@@ -116,8 +116,7 @@ private:
 									CIEAugmentation& cieAugmentation);
 			status_t			_ParseFrameInfoInstructions(
 									CompilationUnit* unit, CfaContext& context,
-									off_t instructionOffset,
-									off_t instructionSize);
+									DataReader& dataReader);
 
 			status_t			_ParsePublicTypesInfo();
 			status_t			_ParsePublicTypesInfo(DataReader& dataReader,