Merge branch 'perf-htmlslim-parser' of https://github.com/jpirnay/crosspoint-reader into mybuild

lib/Epub/Epub/parsers/ChapterHtmlSlimParser.h

@@ -6,6 +6,7 @@
 #include <functional>
 #include <memory>
 #include <string>
+#include <unordered_map>
 #include <vector>
 
 #include "../FootnoteEntry.h"
@@ -94,6 +95,11 @@ class ChapterHtmlSlimParser {
   std::vector<std::pair<int, FootnoteEntry>> pendingFootnotes;  // <wordIndex, entry>
   int wordsExtractedInBlock = 0;
 
+  // Per-chapter caches: resolveStyle and parseInlineStyle are called for every HTML element;
+  // caching by (tag|classAttr) and styleAttr avoids repeated string operations and hash lookups.
+  std::unordered_map<std::string, CssStyle> cssStyleCache_;
+  std::unordered_map<std::string, CssStyle> inlineStyleCache_;
+
   void updateEffectiveInlineStyle();
   void startNewTextBlock(const BlockStyle& blockStyle);
   void flushPartWordBuffer();