From fac9298e2b05ce7918b24965b5784d61518c375c Mon Sep 17 00:00:00 2001
From: abv <abv@opencascade.com>
Date: Thu, 16 Jul 2015 00:34:02 +0300
Subject: [PATCH] 0026448: Method Prepend() of sequence breaks it if argument
 is empty sequence

Check for empty input sequence added in methods Append() and Prepend() of TCollection and NCollection sequences.

Test bugs fclasses bug26448 added
---
 src/NCollection/NCollection_BaseSequence.cxx |  4 ++++
 src/QABugs/QABugs_19.cxx                     | 17 +++++++++++++++++
 src/TCollection/TCollection_BaseSequence.cxx |  4 ++++
 tests/bugs/fclasses/bug26448                 | 10 ++++++++++
 4 files changed, 35 insertions(+)
 create mode 100644 tests/bugs/fclasses/bug26448

diff --git a/src/NCollection/NCollection_BaseSequence.cxx b/src/NCollection/NCollection_BaseSequence.cxx
index fa39c9ae47..ed4fb9fc0b 100644
--- a/src/NCollection/NCollection_BaseSequence.cxx
+++ b/src/NCollection/NCollection_BaseSequence.cxx
@@ -68,6 +68,8 @@ void NCollection_BaseSequence::PAppend (NCollection_SeqNode * theItem)
 
 void NCollection_BaseSequence::PAppend(NCollection_BaseSequence& Other)
 {
+  if (Other.mySize == 0)
+    return;
   if (mySize == 0) {
     mySize         = Other.mySize;
     myFirstItem    = Other.myFirstItem;
@@ -113,6 +115,8 @@ void NCollection_BaseSequence::PPrepend (NCollection_SeqNode * theItem)
 
 void NCollection_BaseSequence::PPrepend (NCollection_BaseSequence& Other)
 {
+  if (Other.mySize == 0)
+    return;
   if (mySize == 0) {
     mySize         = Other.mySize;
     myFirstItem    = Other.myFirstItem;
diff --git a/src/QABugs/QABugs_19.cxx b/src/QABugs/QABugs_19.cxx
index 35dd54732f..0cc6a48de0 100644
--- a/src/QABugs/QABugs_19.cxx
+++ b/src/QABugs/QABugs_19.cxx
@@ -3663,6 +3663,22 @@ static Standard_Integer OCC24923(
   return 0;
 }
 
+static Standard_Integer OCC26448 (Draw_Interpretor& theDI, Standard_Integer, const char **)
+{
+  TColStd_SequenceOfReal aSeq1, aSeq2;
+  aSeq1.Append(11.);
+  aSeq1.Prepend (aSeq2);
+  theDI << "TCollection: 11 -> " << aSeq1.First() << "\n";
+
+  NCollection_Sequence<Standard_Real> nSeq1, nSeq2;
+  nSeq1.Append(11.);
+  nSeq1.Prepend (nSeq2);
+  theDI << "NCollection: 11 -> " << nSeq1.First() << "\n";
+
+  theDI << "OK";
+  return 0;
+}
+
 void QABugs::Commands_19(Draw_Interpretor& theCommands) {
   const char *group = "QABugs";
 
@@ -3734,5 +3750,6 @@ void QABugs::Commands_19(Draw_Interpretor& theCommands) {
   theCommands.Add ("OCC24923", "OCC24923", __FILE__, OCC24923, group);
   theCommands.Add ("OCC26139", "OCC26139 [-boxsize value] [-boxgrid value] [-compgrid value]", __FILE__, OCC26139, group);
   theCommands.Add ("OCC26284", "OCC26284", __FILE__, OCC26284, group);
+  theCommands.Add ("OCC26448", "OCC26448: check method Prepend() of sequence", __FILE__, OCC26448, group);
   return;
 }
diff --git a/src/TCollection/TCollection_BaseSequence.cxx b/src/TCollection/TCollection_BaseSequence.cxx
index 10f753f748..e661124554 100644
--- a/src/TCollection/TCollection_BaseSequence.cxx
+++ b/src/TCollection/TCollection_BaseSequence.cxx
@@ -67,6 +67,8 @@ void TCollection_BaseSequence::PAppend(const Standard_Address newnode)
 // ---------------------------------------------------
 void TCollection_BaseSequence::PAppend(TCollection_BaseSequence& Other)
 {
+  if (Other.Size == 0)
+    return;
   if (Size == 0) {
     Size         = Other.Size;
     FirstItem    = Other.FirstItem;
@@ -104,6 +106,8 @@ void TCollection_BaseSequence::PPrepend(const Standard_Address newnode)
 
 void TCollection_BaseSequence::PPrepend(TCollection_BaseSequence& Other)
 {
+  if (Other.Size == 0)
+    return;
   if (Size == 0) {
     Size         = Other.Size;
     FirstItem    = Other.FirstItem;
diff --git a/tests/bugs/fclasses/bug26448 b/tests/bugs/fclasses/bug26448
new file mode 100644
index 0000000000..fe1f6635eb
--- /dev/null
+++ b/tests/bugs/fclasses/bug26448
@@ -0,0 +1,10 @@
+puts "============"
+puts "OCC26448"
+puts "============"
+puts ""
+#######################################################################
+# Method Prepend() of sequence breaks it if argument is empty sequence
+#######################################################################
+
+pload QAcommands
+OCC26448