added reserve

silverqx · Dec 5, 2022 · 82b3331 · 82b3331
1 parent 1968b40
commit 82b3331
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Showing 3 changed files with 36 additions and 0 deletions.
diff --git a/include/orm/ormconcepts.hpp b/include/orm/ormconcepts.hpp
@@ -88,6 +88,11 @@ namespace Query
     concept DelimiterConcept = std::convertible_to<T, QString> ||
                                std::convertible_to<T, QChar>;
 
+    /*! QString container concept (QStringList or QVector<QString>). */
+    template<typename T>
+    concept QStringContainer = std::convertible_to<T, QStringList> ||
+                               std::convertible_to<T, QVector<QString>>;
+
 } // namespace Orm
 
 TINYORM_END_COMMON_NAMESPACE

diff --git a/include/orm/utils/container.hpp b/include/orm/utils/container.hpp
@@ -28,6 +28,11 @@ namespace Orm::Utils
         template<JoinContainer T, DelimiterConcept D = const QString &>
         static QString
         join(const T &container, D &&delimiter = Constants::COMMA);
+
+        /*! Get a size of the greatest element in the container. */
+        template<QStringContainer T>
+        static QVector<QString>::size_type
+        maxElementSize(const T &container, QVector<QString>::size_type addToElement = 0);
     };
 
     template<JoinContainer T, DelimiterConcept D>
@@ -53,6 +58,31 @@ namespace Orm::Utils
         return columnized;
     }
 
+    template<QStringContainer T>
+    QVector<QString>::size_type
+    Container::maxElementSize(const T &container,
+                              const QVector<QString>::size_type addToElement)
+    {
+        // Nothing to do
+        if (container.empty())
+            return 0;
+
+        QVector<QString>::size_type result = 0;
+
+        for (const auto &element : container)
+            if (const auto elementSize = element.size();
+                elementSize > result
+            )
+                result = elementSize;
+
+        /* This is the reason for the addToElement argument, this algorithm returns 0,
+           if the result is 0. */
+        if (result == 0)
+            return 0;
+
+        return result + addToElement;
+    }
+
 } // namespace Orm::Utils
 
 TINYORM_END_COMMON_NAMESPACE

diff --git a/src/orm/query/grammars/grammar.cpp b/src/orm/query/grammars/grammar.cpp
@@ -580,6 +580,7 @@ QString Grammar::compileDeleteWithJoins(const QueryBuilder &query, const QString
 QString Grammar::concatenate(const QStringList &segments)
 {
     QString result;
+    result.reserve(ContainerUtils::maxElementSize(segments, 1));
 
     for (const auto &segment : segments) {
         if (segment.isEmpty())