From cb64b5cc7d4e9e2e2c7f4fe9e634ed2931d0fc92 Mon Sep 17 00:00:00 2001
From: Jason Wang <jason.ruonan.wang@gmail.com>
Date: Tue, 23 Mar 2021 17:58:23 -0400
Subject: [PATCH] use ssc::Buffer for ssc reader data buffer as well

---
 source/adios2/engine/ssc/SscReader.cpp | 11 ++++++-----
 source/adios2/engine/ssc/SscReader.h   |  2 +-
 source/adios2/engine/ssc/SscReader.tcc |  2 +-
 3 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/source/adios2/engine/ssc/SscReader.cpp b/source/adios2/engine/ssc/SscReader.cpp
index b28fb01768..71206571d2 100644
--- a/source/adios2/engine/ssc/SscReader.cpp
+++ b/source/adios2/engine/ssc/SscReader.cpp
@@ -67,7 +67,8 @@ void SscReader::BeginStepConsequentFixed()
 void SscReader::BeginStepFlexible(StepStatus &status)
 {
     m_AllReceivingWriterRanks.clear();
-    m_Buffer.resize(1, 0);
+    m_Buffer.reserve(1);
+    m_Buffer[0] = 0;
     m_GlobalWritePattern.clear();
     m_GlobalWritePattern.resize(m_StreamSize);
     m_LocalReadPattern.clear();
@@ -199,7 +200,7 @@ void SscReader::PerformGets()
             {
                 totalDataSize += i.second.second;
             }
-            m_Buffer.resize(totalDataSize);
+            m_Buffer.reserve(totalDataSize);
             for (const auto &i : m_AllReceivingWriterRanks)
             {
                 MPI_Win_lock(MPI_LOCK_SHARED, i.first, 0, m_MpiWin);
@@ -246,7 +247,7 @@ void SscReader::PerformGets()
             {                                                                  \
                 continue;                                                      \
             }                                                                  \
-            helper::NdCopy<T>(m_Buffer.data() + b.bufferStart, b.start,        \
+            helper::NdCopy<T>(m_Buffer.data<char>() + b.bufferStart, b.start,  \
                               b.count, true, true,                             \
                               reinterpret_cast<char *>(br.data), br.start,     \
                               br.count, true, true);                           \
@@ -277,7 +278,7 @@ void SscReader::EndStepFixed()
     {
         MPI_Win_free(&m_MpiWin);
         SyncReadPattern();
-        MPI_Win_create(m_Buffer.data(), m_Buffer.size(), 1, MPI_INFO_NULL,
+        MPI_Win_create(m_Buffer.data(), m_Buffer.capacity(), 1, MPI_INFO_NULL,
                        m_StreamComm, &m_MpiWin);
     }
     if (m_MpiMode == "twosided")
@@ -484,7 +485,7 @@ void SscReader::SyncReadPattern()
     {
         totalDataSize += i.second.second;
     }
-    m_Buffer.resize(totalDataSize);
+    m_Buffer.reserve(totalDataSize);
 
     if (m_Verbosity >= 20)
     {
diff --git a/source/adios2/engine/ssc/SscReader.h b/source/adios2/engine/ssc/SscReader.h
index 1c0e2df9de..4bd50b3109 100644
--- a/source/adios2/engine/ssc/SscReader.h
+++ b/source/adios2/engine/ssc/SscReader.h
@@ -48,7 +48,7 @@ class SscReader : public Engine
     ssc::Buffer m_GlobalWritePatternBuffer;
 
     ssc::RankPosMap m_AllReceivingWriterRanks;
-    std::vector<char> m_Buffer;
+    ssc::Buffer m_Buffer;
     MPI_Win m_MpiWin;
     MPI_Group m_WriterGroup;
     MPI_Comm m_StreamComm;
diff --git a/source/adios2/engine/ssc/SscReader.tcc b/source/adios2/engine/ssc/SscReader.tcc
index 8404229e06..8c17d72bc3 100644
--- a/source/adios2/engine/ssc/SscReader.tcc
+++ b/source/adios2/engine/ssc/SscReader.tcc
@@ -138,7 +138,7 @@ void SscReader::GetDeferredCommon(Variable<T> &variable, T *data)
                     if (b.shapeId == ShapeID::GlobalArray ||
                         b.shapeId == ShapeID::LocalArray)
                     {
-                        helper::NdCopy<T>(m_Buffer.data() + b.bufferStart,
+                        helper::NdCopy<T>(m_Buffer.data<char>() + b.bufferStart,
                                           b.start, b.count, true, true,
                                           reinterpret_cast<char *>(data),
                                           vStart, vCount, true, true);