size some stringbuffer to prevent re-alloc

Change-Id: I385587a922c555c320a45dcc6d644315b72510e9
Reviewed-on: https://gerrit.libreoffice.org/81278
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

21 files changed, 123 insertions, 65 deletions

diff --git a/codemaker/source/commonjava/commonjava.cxx b/codemaker/source/commonjava/commonjava.cxx
index 955a0ba5e7cd..bdb1b02b63a7 100644
--- a/codemaker/source/commonjava/commonjava.cxx
+++ b/codemaker/source/commonjava/commonjava.cxx
@@ -39,7 +39,7 @@ namespace codemaker { namespace java {
 OString translateUnoToJavaType(
     codemaker::UnoType::Sort sort, OString const & nucleus, bool referenceType)
 {
-    OStringBuffer buf;
+    OStringBuffer buf(128);
     if (sort <= codemaker::UnoType::Sort::Any) {
         OString const javaTypes[static_cast<int>(codemaker::UnoType::Sort::Any) + 1][2] = {
             { "void", "java/lang/Void" },
diff --git a/codemaker/source/cppumaker/cpputype.cxx b/codemaker/source/cppumaker/cpputype.cxx
index a16256d4c353..dcec84ccdc3f 100644
--- a/codemaker/source/cppumaker/cpputype.cxx
+++ b/codemaker/source/cppumaker/cpputype.cxx
@@ -2400,6 +2400,28 @@ void PolyStructType::dumpLightGetCppuType(FileStream & out)
         << "static ::typelib_TypeDescriptionReference * the_type = 0;\n"
         << indent() << "if (the_type == 0) {\n";
     inc();
+
+    out << "#ifdef LIBO_INTERNAL_ONLY\n";
+
+    out << indent() << "::rtl::OString the_buffer = \"" << name_
+        << "<\" +\n";
+    for (std::vector< OUString >::const_iterator i(
+             entity_->getTypeParameters().begin());
+         i != entity_->getTypeParameters().end();) {
+        out << indent()
+            << ("::rtl::OUStringToOString("
+                "::cppu::getTypeFavourChar(static_cast< ");
+        dumpTypeParameterName(out, *i);
+        out << " * >(0)).getTypeName(), RTL_TEXTENCODING_UTF8) +\n";
+        ++i;
+        if (i != entity_->getTypeParameters().end()) {
+            out << indent() << "\",\" +\n";
+        }
+    }
+    out << indent() << "\">\";\n";
+
+    out << "#else\n";
+
     out << indent() << "::rtl::OStringBuffer the_buffer(\"" << name_
         << "<\");\n";
     for (std::vector< OUString >::const_iterator i(
@@ -2415,9 +2437,14 @@ void PolyStructType::dumpLightGetCppuType(FileStream & out)
             out << indent() << "the_buffer.append(',');\n";
         }
     }
-    out << indent() << "the_buffer.append('>');\n" << indent()
+    out << indent() << "the_buffer.append('>');\n";
+
+    out << "#endif\n";
+
+    out << indent()
         << "::typelib_static_type_init(&the_type, " << getTypeClass(name_, true)
         << ", the_buffer.getStr());\n";
+
     dec();
     out << indent() << "}\n" << indent()
         << "return *reinterpret_cast< ::css::uno::Type * >(&the_type);\n";
@@ -2506,6 +2533,27 @@ void PolyStructType::dumpComprehensiveGetCppuType(FileStream & out)
     out << indent() << "::css::uno::Type * operator()() const\n"
         << indent() << "{\n";
     inc();
+
+    out << "#ifdef LIBO_INTERNAL_ONLY\n";
+    out << indent()
+        << "::rtl::OUString the_name =\n";
+    out << indent() << "\"" << name_ << "<\" +\n";
+    for (std::vector< OUString >::const_iterator i(
+             entity_->getTypeParameters().begin());
+         i != entity_->getTypeParameters().end();) {
+        out << indent()
+            << "::cppu::getTypeFavourChar(static_cast< ";
+        dumpTypeParameterName(out, *i);
+        out << " * >(0)).getTypeName() +\n";
+        ++i;
+        if (i != entity_->getTypeParameters().end()) {
+            out << indent()
+                << "\",\" +\n";
+        }
+    }
+    out << indent()
+        << "\">\";\n";
+    out << "#else\n";
     out << indent() << "::rtl::OUStringBuffer the_buffer;\n" << indent()
         << "the_buffer.append(\"" << name_ << "<\");\n";
     for (std::vector< OUString >::const_iterator i(
@@ -2522,9 +2570,10 @@ void PolyStructType::dumpComprehensiveGetCppuType(FileStream & out)
                     "static_cast< ::sal_Unicode >(','));\n");
         }
     }
-    out << indent() << "the_buffer.append(static_cast< ::sal_Unicode >('>'));\n"
-        << indent()
+    out << indent() << "the_buffer.append(static_cast< ::sal_Unicode >('>'));\n";
+    out << indent()
         << "::rtl::OUString the_name(the_buffer.makeStringAndClear());\n";
+    out << "#endif\n";
     std::map< OUString, sal_uInt32 > parameters;
     std::map< OUString, sal_uInt32 > types;
     std::vector< unoidl::PolymorphicStructTypeTemplateEntity::Member >::
diff --git a/codemaker/source/javamaker/javatype.cxx b/codemaker/source/javamaker/javatype.cxx
index 0616d8f08771..16c2ef73e089 100644
--- a/codemaker/source/javamaker/javatype.cxx
+++ b/codemaker/source/javamaker/javatype.cxx
@@ -89,7 +89,7 @@ OUString createUnoName(
     rtl::Reference< TypeManager > const & manager, OUString const & nucleus,
     sal_Int32 rank, std::vector< OUString > const & arguments)
 {
-    OUStringBuffer buf;
+    OUStringBuffer buf(256);
     appendUnoName(manager, nucleus, rank, arguments, &buf);
     return buf.makeStringAndClear();
 }
@@ -293,8 +293,8 @@ SpecialType getFieldDescriptor(
     PolymorphicUnoType * polymorphicUnoType)
 {
     assert(descriptor != nullptr);
-    OStringBuffer desc;
-    OStringBuffer sig;
+    OStringBuffer desc(64);
+    OStringBuffer sig(64);
     bool needsSig = false;
     SpecialType specialType = translateUnoTypeToDescriptor(
         manager, type, false, false, dependencies, &desc, &sig, &needsSig,
@@ -331,9 +331,9 @@ public:
 private:
     rtl::Reference< TypeManager > m_manager;
     std::set<OUString> * m_dependencies;
-    OStringBuffer m_descriptorStart;
+    OStringBuffer m_descriptorStart{16*1024};
     OString m_descriptorEnd;
-    OStringBuffer m_signatureStart;
+    OStringBuffer m_signatureStart{16*1024};
     OString m_signatureEnd;
     bool m_needsSignature;
 };
@@ -347,9 +347,9 @@ MethodDescriptor::MethodDescriptor(
     assert(dependencies != nullptr);
     m_descriptorStart.append('(');
     m_signatureStart.append('(');
-    OStringBuffer descEnd;
+    OStringBuffer descEnd(128);
     descEnd.append(')');
-    OStringBuffer sigEnd;
+    OStringBuffer sigEnd(128);
     sigEnd.append(')');
     SpecialType special = translateUnoTypeToDescriptor(
         m_manager, returnType, false, false, m_dependencies, &descEnd, &sigEnd,
@@ -896,7 +896,7 @@ sal_uInt16 addFieldInit(
                     dynamic_cast< unoidl::EnumTypeEntity * >(ent.get()));
                 assert(ent2.is());
                 code->loadLocalReference(0);
-                OStringBuffer descBuf;
+                OStringBuffer descBuf(128);
                 translateUnoTypeToDescriptor(
                     manager, sort, nucleus, 0, std::vector< OUString >(), false,
                     false, dependencies, &descBuf, nullptr, nullptr, nullptr);
@@ -917,7 +917,7 @@ sal_uInt16 addFieldInit(
                 code->instrInvokespecial(
                     codemaker::convertString(nucleus).replace('.', '/'),
                     "<init>", "()V");
-                OStringBuffer desc;
+                OStringBuffer desc(128);
                 translateUnoTypeToDescriptor(
                     manager, sort, nucleus, 0, args, false, false, dependencies,
                     &desc, nullptr, nullptr, nullptr);
@@ -947,13 +947,13 @@ sal_uInt16 addFieldInit(
                     false));
         }
     } else {
-        OStringBuffer desc;
+        OStringBuffer desc(128);
         translateUnoTypeToDescriptor(
             manager, sort, nucleus, rank - 1, std::vector< OUString >(), false,
             false, dependencies, &desc, nullptr, nullptr, nullptr);
         code->instrAnewarray(desc.makeStringAndClear());
     }
-    OStringBuffer desc;
+    OStringBuffer desc(128);
     translateUnoTypeToDescriptor(
         manager, sort, nucleus, rank, std::vector< OUString >(), false, false,
         dependencies, &desc, nullptr, nullptr, nullptr);
@@ -1440,7 +1440,8 @@ void handlePolyStructType(
     assert(entity.is());
     OString className(codemaker::convertString(name).replace('.', '/'));
     std::map< OUString, sal_Int32 > typeParameters;
-    OStringBuffer sig("<");
+    OStringBuffer sig(128);
+    sig.append("<");
     sal_Int32 index = 0;
     for (const OUString& param : entity->getTypeParameters())
     {
diff --git a/comphelper/qa/unit/base64_test.cxx b/comphelper/qa/unit/base64_test.cxx
index 60f6c68d5631..97f7b78aae7a 100644
--- a/comphelper/qa/unit/base64_test.cxx
+++ b/comphelper/qa/unit/base64_test.cxx
@@ -49,16 +49,18 @@ public:
 
 void Base64Test::testBase64Encode()
 {
-    OUStringBuffer aBuffer;
+    OUStringBuffer aBuffer(32);
     uno::Sequence<sal_Int8> inputSequence;
 
     inputSequence = { 0, 0, 0, 0, 0, 1, 2, 3 };
     comphelper::Base64::encode(aBuffer, inputSequence);
-    CPPUNIT_ASSERT_EQUAL(OUString("AAAAAAABAgM="), aBuffer.makeStringAndClear());
+    CPPUNIT_ASSERT_EQUAL(OUString("AAAAAAABAgM="), aBuffer.toString());
+    aBuffer.setLength(0);
 
     inputSequence = { 5, 2, 3, 0, 0, 1, 2, 3 };
     comphelper::Base64::encode(aBuffer, inputSequence);
-    CPPUNIT_ASSERT_EQUAL(OUString("BQIDAAABAgM="), aBuffer.makeStringAndClear());
+    CPPUNIT_ASSERT_EQUAL(OUString("BQIDAAABAgM="), aBuffer.toString());
+    aBuffer.setLength(0);
 
     inputSequence = { sal_Int8(sal_uInt8(200)), 31, 77, 111, 0, 1, 2, 3 };
     comphelper::Base64::encode(aBuffer, inputSequence);
@@ -84,16 +86,18 @@ void Base64Test::testBase64Decode()
 
 void Base64Test::testBase64EncodeForOStringBuffer()
 {
-    OStringBuffer aBuffer;
+    OStringBuffer aBuffer(32);
     uno::Sequence<sal_Int8> inputSequence;
 
     inputSequence = { 0, 0, 0, 0, 0, 1, 2, 3 };
     comphelper::Base64::encode(aBuffer, inputSequence);
-    CPPUNIT_ASSERT_EQUAL(OString("AAAAAAABAgM="), aBuffer.makeStringAndClear());
+    CPPUNIT_ASSERT_EQUAL(OString("AAAAAAABAgM="), aBuffer.toString());
+    aBuffer.setLength(0);
 
     inputSequence = { 5, 2, 3, 0, 0, 1, 2, 3 };
     comphelper::Base64::encode(aBuffer, inputSequence);
-    CPPUNIT_ASSERT_EQUAL(OString("BQIDAAABAgM="), aBuffer.makeStringAndClear());
+    CPPUNIT_ASSERT_EQUAL(OString("BQIDAAABAgM="), aBuffer.toString());
+    aBuffer.setLength(0);
 
     inputSequence = { sal_Int8(sal_uInt8(200)), 31, 77, 111, 0, 1, 2, 3 };
     comphelper::Base64::encode(aBuffer, inputSequence);
diff --git a/comphelper/source/misc/docpasswordhelper.cxx b/comphelper/source/misc/docpasswordhelper.cxx
index cf665dd6c147..989863fefbc6 100644
--- a/comphelper/source/misc/docpasswordhelper.cxx
+++ b/comphelper/source/misc/docpasswordhelper.cxx
@@ -308,7 +308,7 @@ OUString DocPasswordHelper::GetOoxHashAsBase64(
     css::uno::Sequence<sal_Int8> aSeq( GetOoxHashAsSequence( rPassword, rSaltValue, nSpinCount,
                 eIterCount, rAlgorithmName));
 
-    OUStringBuffer aBuf;
+    OUStringBuffer aBuf((aSeq.getLength()+2)/3*4);
     comphelper::Base64::encode( aBuf, aSeq);
     return aBuf.makeStringAndClear();
 }
diff --git a/editeng/source/editeng/editdoc.cxx b/editeng/source/editeng/editdoc.cxx
index 45c2cb163e06..ad71436ab89f 100644
--- a/editeng/source/editeng/editdoc.cxx
+++ b/editeng/source/editeng/editdoc.cxx
@@ -1629,7 +1629,7 @@ OUString ContentNode::GetExpandedText(sal_Int32 nStartPos, sal_Int32 nEndPos) co
     DBG_ASSERT( nStartPos <= nEndPos, "Start and End reversed?" );
 
     sal_Int32 nIndex = nStartPos;
-    OUStringBuffer aStr;
+    OUStringBuffer aStr(256);
     const EditCharAttrib* pNextFeature = GetCharAttribs().FindFeature( nIndex );
     while ( nIndex < nEndPos )
     {
diff --git a/editeng/source/editeng/impedit2.cxx b/editeng/source/editeng/impedit2.cxx
index 5be0d3113ce5..c65dc164ea4a 100644
--- a/editeng/source/editeng/impedit2.cxx
+++ b/editeng/source/editeng/impedit2.cxx
@@ -287,7 +287,7 @@ OUString ImpEditEngine::GetSelected( const EditSelection& rSel  ) const
 
     OSL_ENSURE( nStartNode <= nEndNode, "Selection not sorted ?" );
 
-    OUStringBuffer aText;
+    OUStringBuffer aText(256);
     const OUString aSep = EditDoc::GetSepStr( LINEEND_LF );
 
     // iterate over the paragraphs ...
diff --git a/i18npool/qa/cppunit/test_breakiterator.cxx b/i18npool/qa/cppunit/test_breakiterator.cxx
index 7daf9e98e573..a1d423879109 100644
--- a/i18npool/qa/cppunit/test_breakiterator.cxx
+++ b/i18npool/qa/cppunit/test_breakiterator.cxx
@@ -792,10 +792,10 @@ void TestBreakIterator::testWeak()
         for (sal_Int32 i = 0; i < aWeaks.getLength(); ++i)
         {
             sal_Int16 nScript = m_xBreak->getScriptType(aWeaks, i);
-            OStringBuffer aMsg;
-            aMsg.append("Char 0x");
-            aMsg.append(static_cast<sal_Int32>(aWeaks[i]), 16);
-            aMsg.append(" should have been weak");
+            OString aMsg =
+                "Char 0x" +
+                OString::number(static_cast<sal_Int32>(aWeaks[i]), 16) +
+                " should have been weak";
             CPPUNIT_ASSERT_EQUAL_MESSAGE(aMsg.getStr(),
                 i18n::ScriptType::WEAK, nScript);
         }
@@ -831,10 +831,10 @@ void TestBreakIterator::testAsian()
         for (sal_Int32 i = 0; i < aAsians.getLength(); ++i)
         {
             sal_Int16 nScript = m_xBreak->getScriptType(aAsians, i);
-            OStringBuffer aMsg;
-            aMsg.append("Char 0x");
-            aMsg.append(static_cast<sal_Int32>(aAsians[i]), 16);
-            aMsg.append(" should have been asian");
+            OString aMsg =
+                "Char 0x" +
+                OString::number(static_cast<sal_Int32>(aAsians[i]), 16) +
+                " should have been asian";
             CPPUNIT_ASSERT_EQUAL_MESSAGE(aMsg.getStr(),
                 i18n::ScriptType::ASIAN, nScript);
         }
diff --git a/i18npool/source/breakiterator/xdictionary.cxx b/i18npool/source/breakiterator/xdictionary.cxx
index f21e377c68c0..b349066d06d7 100644
--- a/i18npool/source/breakiterator/xdictionary.cxx
+++ b/i18npool/source/breakiterator/xdictionary.cxx
@@ -165,13 +165,13 @@ void xdictionary::initDictionaryData(const sal_Char *pLang)
     aEntry.maLang = OString( pLang, strlen( pLang ) );
 
 #ifdef SAL_DLLPREFIX
-    OUStringBuffer aBuf( sal::static_int_cast<int>(strlen(pLang) + 7 + 6) );    // mostly "lib*.so" (with * == dict_zh)
-    aBuf.append( SAL_DLLPREFIX );
+    OString sModuleName = // mostly "lib*.so" (with * == dict_zh)
+        SAL_DLLPREFIX
 #else
-    OUStringBuffer aBuf( sal::static_int_cast<int>(strlen(pLang) + 7 + 4) );    // mostly "*.dll" (with * == dict_zh)
+    OString sModuleName = // mostly "*.dll" (with * == dict_zh)
 #endif
-    aBuf.append( "dict_" ).appendAscii( pLang ).append( SAL_DLLEXTENSION );
-    aEntry.mhModule = osl_loadModuleRelative( &thisModule, aBuf.makeStringAndClear().pData, SAL_LOADMODULE_DEFAULT );
+        "dict_" + rtl::OStringView(pLang) + SAL_DLLEXTENSION;
+    aEntry.mhModule = osl_loadModuleRelativeAscii( &thisModule, sModuleName.getStr(), SAL_LOADMODULE_DEFAULT );
     if( aEntry.mhModule ) {
         oslGenericFunction func;
         func = osl_getAsciiFunctionSymbol( aEntry.mhModule, "getExistMark" );
diff --git a/i18npool/source/collator/gencoll_rule.cxx b/i18npool/source/collator/gencoll_rule.cxx
index fb0349f19b84..33be2a5a2c56 100644
--- a/i18npool/source/collator/gencoll_rule.cxx
+++ b/i18npool/source/collator/gencoll_rule.cxx
@@ -88,8 +88,12 @@ SAL_IMPLEMENT_MAIN_WITH_ARGS(argc, argv)
         exit(1);
     }
 
+    fseek(fp, 0L, SEEK_END);
+    int fileSize = ftell(fp);
+    rewind(fp);
+
     sal_Char str[1024];
-    OUStringBuffer Obuf;
+    OUStringBuffer Obuf(fileSize);
     while (fgets(str, 1024, fp)) {
         // don't convert last new line character to Ostr.
         sal_Int32 len = strlen(str) - 1;
diff --git a/i18npool/source/indexentry/genindex_data.cxx b/i18npool/source/indexentry/genindex_data.cxx
index d5bad8b18def..128fad664bfb 100644
--- a/i18npool/source/indexentry/genindex_data.cxx
+++ b/i18npool/source/indexentry/genindex_data.cxx
@@ -49,7 +49,8 @@ SAL_IMPLEMENT_MAIN_WITH_ARGS(argc, argv)
     sal_Int32 address[MAX_ADDRESS];
     for (i=0; i<MAX_ADDRESS; i++) address[i]=-1;
     OUString sep('|');
-    OUStringBuffer result=sep;
+    OUStringBuffer result(64*1024);
+    result.append(sep);
     sal_Int32 max=0;
 
     sal_Char str[1024];
diff --git a/idlc/source/aststructinstance.cxx b/idlc/source/aststructinstance.cxx
index e7723d19bd2d..878745793fd2 100644
--- a/idlc/source/aststructinstance.cxx
+++ b/idlc/source/aststructinstance.cxx
@@ -31,7 +31,8 @@ namespace {
 OString createName(
     AstType const * typeTemplate, DeclList const * typeArguments)
 {
-    OStringBuffer buf(typeTemplate->getScopedName());
+    OStringBuffer buf(64);
+    buf.append(typeTemplate->getScopedName());
     if (typeArguments != nullptr) {
         buf.append('<');
         for (DeclList::const_iterator i(typeArguments->begin());
diff --git a/idlc/source/idlccompile.cxx b/idlc/source/idlccompile.cxx
index 56dbfe4e77ec..8d3897890e0f 100644
--- a/idlc/source/idlccompile.cxx
+++ b/idlc/source/idlccompile.cxx
@@ -238,7 +238,6 @@ sal_Int32 compileFile(const OString * pathname)
     lCppArgs.emplace_back("-C");
     lCppArgs.emplace_back("-zI");
 
-    OStringBuffer cppArgs(256);
     Options* pOptions = idlc()->getOptions();
 
     OString filePath;
@@ -250,10 +249,9 @@ sal_Int32 compileFile(const OString * pathname)
 
         if ( !filePath.isEmpty() )
         {
-            cppArgs.append("-I");
-            cppArgs.append(filePath);
+            OString cppArgs = "-I" + filePath;
             lCppArgs.push_back(OStringToOUString(
-                cppArgs.makeStringAndClear().replace('\\', '/'),
+                cppArgs.replace('\\', '/'),
                 RTL_TEXTENCODING_UTF8));
         }
     }
@@ -284,11 +282,9 @@ sal_Int32 compileFile(const OString * pathname)
 
     lCppArgs.emplace_back("-o");
 
-    cppArgs.append(preprocFile);
-    lCppArgs.push_back(OStringToOUString(cppArgs.makeStringAndClear(), RTL_TEXTENCODING_UTF8));
+    lCppArgs.push_back(OStringToOUString(preprocFile, RTL_TEXTENCODING_UTF8));
 
-    cppArgs.append(tmpFile);
-    lCppArgs.push_back(OStringToOUString(cppArgs.makeStringAndClear(), RTL_TEXTENCODING_UTF8));
+    lCppArgs.push_back(OStringToOUString(tmpFile, RTL_TEXTENCODING_UTF8));
 
     OUString cpp;
     OUString startDir;
diff --git a/idlc/source/idlcproduce.cxx b/idlc/source/idlcproduce.cxx
index f87992d6b859..ff9ca2f2d47f 100644
--- a/idlc/source/idlcproduce.cxx
+++ b/idlc/source/idlcproduce.cxx
@@ -44,7 +44,7 @@ static std::list< OString >* pCreatedDirectories = nullptr;
 static bool checkOutputPath(const OString& completeName)
 {
     OString sysPathName = convertToAbsoluteSystemPath(completeName);
-    OStringBuffer buffer(sysPathName.getLength());
+    OStringBuffer buffer(sysPathName.getLength()+16);
 
     if ( sysPathName.indexOf( SEPARATOR ) == -1 )
         return true;
diff --git a/include/comphelper/unwrapargs.hxx b/include/comphelper/unwrapargs.hxx
index a7f7f0001898..77ef0ace16c1 100644
--- a/include/comphelper/unwrapargs.hxx
+++ b/include/comphelper/unwrapargs.hxx
@@ -79,13 +79,13 @@ namespace detail {
         }
         if( !fromAny( seq[nArg], &v ) )
         {
-            OUStringBuffer buf;
-            buf.append( "Cannot extract ANY { " );
-            buf.append( seq[nArg].getValueType().getTypeName() );
-            buf.append( " } to " );
-            buf.append( ::cppu::UnoType<T>::get().getTypeName() );
-            buf.append( u'!' );
-            return unwrapArgsError( buf.makeStringAndClear(), nArg, args... );
+            OUString msg =
+                "Cannot extract ANY { " +
+                seq[nArg].getValueType().getTypeName() +
+                " } to " +
+                ::cppu::UnoType<T>::get().getTypeName() +
+                "!";
+            return unwrapArgsError( msg, nArg, args... );
         }
         return unwrapArgs( seq, ++nArg, args... );
     }
diff --git a/registry/source/keyimpl.cxx b/registry/source/keyimpl.cxx
index d969cbaa32c5..d7baabe008da 100644
--- a/registry/source/keyimpl.cxx
+++ b/registry/source/keyimpl.cxx
@@ -970,7 +970,8 @@ OStoreDirectory ORegKey::getStoreDir() const
 
 OUString ORegKey::getFullPath(OUString const & path) const {
     OSL_ASSERT(!m_name.isEmpty() && !path.isEmpty());
-    OUStringBuffer b(m_name);
+    OUStringBuffer b(32);
+    b.append(m_name);
     if (!b.isEmpty() && b[b.getLength() - 1] == '/') {
         if (path[0] == '/') {
             b.append(std::u16string_view(path).substr(1));
diff --git a/registry/source/regimpl.cxx b/registry/source/regimpl.cxx
index ab7dcb09888e..43e12cb8f375 100644
--- a/registry/source/regimpl.cxx
+++ b/registry/source/regimpl.cxx
@@ -629,7 +629,7 @@ RegError ORegistry::createKey(RegKeyHandle hKey, const OUString& keyName,
     }
 
     OStoreDirectory rStoreDir;
-    OUStringBuffer  sFullPath(sFullKeyName.getLength());
+    OUStringBuffer  sFullPath(sFullKeyName.getLength()+16);
     OUString        token;
 
     sFullPath.append('/');
diff --git a/sax/qa/cppunit/test_converter.cxx b/sax/qa/cppunit/test_converter.cxx
index 536aa53bbdcd..525e110c1a46 100644
--- a/sax/qa/cppunit/test_converter.cxx
+++ b/sax/qa/cppunit/test_converter.cxx
@@ -90,7 +90,7 @@ void doTest(util::Duration const & rid, char const*const pis,
     CPPUNIT_ASSERT_EQUAL(rid.Seconds, od.Seconds);
     CPPUNIT_ASSERT_EQUAL(rid.NanoSeconds, od.NanoSeconds);
     CPPUNIT_ASSERT_EQUAL(rid.Negative, od.Negative);
-    OUStringBuffer buf;
+    OUStringBuffer buf(64);
     Converter::convertDuration(buf, od);
     SAL_INFO("sax.cppunit","" << buf.toString());
     CPPUNIT_ASSERT(buf.makeStringAndClear().equalsAscii(pos));
@@ -159,7 +159,7 @@ void doTest(util::DateTime const & rdt, char const*const pis,
     SAL_INFO("sax.cppunit","Y:" << odt.Year << " M:" << odt.Month << " D:" << odt.Day << "  H:" << odt.Hours << " M:" << odt.Minutes << " S:" << odt.Seconds << " nS:" << odt.NanoSeconds << " UTC: " << static_cast<bool>(odt.IsUTC));
     CPPUNIT_ASSERT(bSuccess);
     CPPUNIT_ASSERT(eqDateTime(rdt, odt));
-    OUStringBuffer buf;
+    OUStringBuffer buf(32);
     Converter::convertDateTime(buf, odt, nullptr, true);
     SAL_INFO("sax.cppunit","" << buf.toString());
     CPPUNIT_ASSERT_EQUAL(OUString::createFromAscii(pos),
@@ -253,7 +253,7 @@ void doTestTime(util::DateTime const & rdt, char const*const pis,
     SAL_INFO("sax.cppunit","Y:" << odt.Year << " M:" << odt.Month << " D:" << odt.Day << "  H:" << odt.Hours << " M:" << odt.Minutes << " S:" << odt.Seconds << " nS:" << odt.NanoSeconds << " UTC: " << static_cast<bool>(odt.IsUTC));
     CPPUNIT_ASSERT(bSuccess);
     CPPUNIT_ASSERT(eqDateTime(rdt, odt));
-    OUStringBuffer buf;
+    OUStringBuffer buf(32);
     Converter::convertTimeOrDateTime(buf, odt);
     SAL_INFO("sax.cppunit","" << buf.toString());
     CPPUNIT_ASSERT_EQUAL(OUString::createFromAscii(pos),
diff --git a/sax/source/fastparser/fastparser.cxx b/sax/source/fastparser/fastparser.cxx
index ac04d1522a24..7383b8c339ea 100644
--- a/sax/source/fastparser/fastparser.cxx
+++ b/sax/source/fastparser/fastparser.cxx
@@ -551,7 +551,8 @@ OUString lclGetErrorMessage( xmlParserCtxtPtr ctxt, const OUString& sSystemId, s
         pMessage = error->message;
     else
         pMessage = "unknown error";
-    OUStringBuffer aBuffer( "[" );
+    OUStringBuffer aBuffer( 128 );
+    aBuffer.append( "[" );
     aBuffer.append( sSystemId );
     aBuffer.append( " line " );
     aBuffer.append( nLine );
diff --git a/tools/source/ref/globname.cxx b/tools/source/ref/globname.cxx
index 6cbff020669c..eed9b8fd5a04 100644
--- a/tools/source/ref/globname.cxx
+++ b/tools/source/ref/globname.cxx
@@ -227,7 +227,7 @@ bool SvGlobalName::MakeId( const OUString & rIdStr )
 
 OUString SvGlobalName::GetHexName() const
 {
-    OStringBuffer aHexBuffer;
+    OStringBuffer aHexBuffer(36);
 
     sal_Char buf[ 10 ];
     sprintf( buf, "%8.8" SAL_PRIXUINT32, pImp->szData.Data1 );
diff --git a/xmloff/source/core/nmspmap.cxx b/xmloff/source/core/nmspmap.cxx
index 44e619c0f348..7aa50542b5e8 100644
--- a/xmloff/source/core/nmspmap.cxx
+++ b/xmloff/source/core/nmspmap.cxx
@@ -235,9 +235,9 @@ OUString SvXMLNamespaceMap::GetQNameByKey( sal_uInt16 nKey,
                 NameSpaceMap::const_iterator aIter = aNameMap.find ( nKey );
                 if ( aIter != aNameMap.end() )
                 {
-                    OUStringBuffer sQName;
                     // ...if it's in our map, make the prefix
                     const OUString & prefix( (*aIter).second->sPrefix );
+                    OUStringBuffer sQName(prefix.getLength() + 1 + rLocalName.getLength());
                     if (!prefix.isEmpty()) // not default namespace
                     {
                         sQName.append( prefix );