From e54ec6c1915867416b0fd3600809a0ddcbaac331 Mon Sep 17 00:00:00 2001
From: Vadim Zeitlin <vadim@wxwidgets.org>
Date: Sun, 20 May 2018 18:05:16 +0200
Subject: [PATCH] Add wxTarHeaderBlock::Clear() method encapsulating memset()

Using memset() with objects of (non-trivial) class type results in a
-Wclass-memaccess warning with g++ 8, so avoid doing this.

Add a Clear() method allowing to do the same thing without breaking
encapsulation.
---
 src/common/tarstrm.cpp | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/src/common/tarstrm.cpp b/src/common/tarstrm.cpp
index 247bcc3b18..f2f7109f28 100644
--- a/src/common/tarstrm.cpp
+++ b/src/common/tarstrm.cpp
@@ -128,7 +128,9 @@ class wxTarHeaderBlock
 {
 public:
     wxTarHeaderBlock()
-        { memset(data, 0, sizeof(data)); }
+        { Clear(); }
+
+    void Clear(size_t len = 0) { memset(data, 0, len ? len : sizeof(data)); }
 
     bool Read(wxInputStream& in);
     bool Write(wxOutputStream& out);
@@ -1186,7 +1188,7 @@ bool wxTarOutputStream::CloseEntry()
     if (IsOk()) {
         wxFileOffset size = RoundUpSize(m_pos);
         if (size > m_pos) {
-            memset(m_hdr, 0, size - m_pos);
+            m_hdr->Clear(size - m_pos);
             m_parent_o_stream->Write(m_hdr, size - m_pos);
             m_lasterror = m_parent_o_stream->GetLastError();
         }
@@ -1210,7 +1212,7 @@ bool wxTarOutputStream::Close()
     if (!CloseEntry() || (m_tarsize == 0 && m_endrecWritten))
         return false;
 
-    memset(m_hdr, 0, sizeof(*m_hdr));
+    m_hdr->Clear();
     int count = (RoundUpSize(m_tarsize + 2 * TAR_BLOCKSIZE, m_BlockingFactor)
                     - m_tarsize) / TAR_BLOCKSIZE;
     while (count--)
@@ -1225,7 +1227,7 @@ bool wxTarOutputStream::Close()
 
 bool wxTarOutputStream::WriteHeaders(wxTarEntry& entry)
 {
-    memset(m_hdr, 0, sizeof(*m_hdr));
+    m_hdr->Clear();
 
     SetHeaderPath(entry.GetName(wxPATH_UNIX));
 
@@ -1271,7 +1273,7 @@ bool wxTarOutputStream::WriteHeaders(wxTarEntry& entry)
         // so prepare a regular header block for the pseudo-file.
         if (!m_hdr2)
             m_hdr2 = new wxTarHeaderBlock;
-        memset(m_hdr2, 0, sizeof(*m_hdr2));
+        m_hdr2->Clear();
 
         // an old tar that doesn't understand extended headers will
         // extract it as a file, so give these fields reasonable values