From 5dd92c395a9e318b22dec72938963ded423ad37b Mon Sep 17 00:00:00 2001
From: asemenov <asemenov_ext@opencascade.com>
Date: Fri, 17 Sep 2021 18:46:43 +0300
Subject: [PATCH] 0029478: Crash because bSplineSurfaceWithKnots is NULL.

Modified the method void RWStepGeom_RWBSplineSurfaceWithKnotsAndRationalBSplineSurface::ReadStep
Added processing B spline surface with knots and rational B spline surface with empty data in the name field
Added test
---
 ...SurfaceWithKnotsAndRationalBSplineSurface.cxx | 16 +++++++++++-----
 tests/bugs/step/bug29478                         | 11 +++++++++++
 2 files changed, 22 insertions(+), 5 deletions(-)
 create mode 100644 tests/bugs/step/bug29478

diff --git a/src/RWStepGeom/RWStepGeom_RWBSplineSurfaceWithKnotsAndRationalBSplineSurface.cxx b/src/RWStepGeom/RWStepGeom_RWBSplineSurfaceWithKnotsAndRationalBSplineSurface.cxx
index 670c034a72..adc7ba26b3 100644
--- a/src/RWStepGeom/RWStepGeom_RWBSplineSurfaceWithKnotsAndRationalBSplineSurface.cxx
+++ b/src/RWStepGeom/RWStepGeom_RWBSplineSurfaceWithKnotsAndRationalBSplineSurface.cxx
@@ -261,15 +261,21 @@ void RWStepGeom_RWBSplineSurfaceWithKnotsAndRationalBSplineSurface::ReadStep
 
 	// --- Instance of plex component RepresentationItem ---
 
-	if (!data->CheckNbParams(num,1,ach,"representation_item")) return;
-
 	// --- field : name ---
 
 	Handle(TCollection_HAsciiString) aName;
-	//szv#4:S4163:12Mar99 `Standard_Boolean stat14 =` not needed
-	data->ReadString (num,1,"name",ach,aName);
 
-//	num = data->NextForComplex(num);
+  if (!data->CheckNbParams(num, 1, ach, "representation_item"))
+  {
+    aName = new TCollection_HAsciiString("");
+  }
+  else
+  {
+    //szv#4:S4163:12Mar99 `Standard_Boolean stat14 =` not needed
+    data->ReadString(num, 1, "name", ach, aName);
+  }
+
+  //	num = data->NextForComplex(num);
 	data->NamedForComplex("SURFACE", "SRFC",num0,num,ach);
 
 	//--- Initialisation of the red entity ---
diff --git a/tests/bugs/step/bug29478 b/tests/bugs/step/bug29478
new file mode 100644
index 0000000000..7b17780629
--- /dev/null
+++ b/tests/bugs/step/bug29478
@@ -0,0 +1,11 @@
+puts "============"
+puts "OCC29478"
+puts "============"
+puts ""
+#####################################################
+# Crash because bSplineSurfaceWithKnots is NULL
+#####################################################
+
+set aFilePath [locate_data_file bug29478.stp]
+testreadstep "$aFilePath" orig
+checkshape orig