Smarter cache eviction

lib/EpdFont/FontDecompressor.cpp

@@ -219,13 +219,6 @@ int32_t FontDecompressor::findGlyphIndex(const EpdFontData* fontData, uint32_t c
 int FontDecompressor::prewarmCache(const EpdFontData* fontData, const char* utf8Text) {
   if (!fontData || !fontData->groups || !utf8Text) return 0;
 
-  // Allocate the next available slot (caller must call freePageBuffer/clearCache to reset)
-  if (pageSlotCount >= MAX_PAGE_SLOTS) {
-    LOG_ERR("FDC", "All %u page buffer slots full, cannot prewarm fontData=%p", MAX_PAGE_SLOTS, (void*)fontData);
-    return -1;
-  }
-  PageSlot& slot = pageSlots[pageSlotCount];
-
   // Step 1: Collect unique glyph indices needed for this page
   uint32_t neededGlyphs[MAX_PAGE_GLYPHS];
   uint16_t glyphCount = 0;
@@ -239,7 +232,29 @@ int FontDecompressor::prewarmCache(const EpdFontData* fontData, const char* utf8
     int32_t glyphIdx = findGlyphIndex(fontData, cp);
     if (glyphIdx < 0) continue;
 
-    // Deduplicate
+    // Deduplicate against already prewarmed slots
+    bool alreadyCached = false;
+    for (uint8_t s = 0; s < pageSlotCount; s++) {
+      if (pageSlots[s].fontData != fontData || pageSlots[s].glyphCount == 0) continue;
+      int left = 0, right = pageSlots[s].glyphCount - 1;
+      while (left <= right) {
+        int mid = left + (right - left) / 2;
+        if (pageSlots[s].glyphs[mid].glyphIndex == static_cast<uint32_t>(glyphIdx)) {
+          if (pageSlots[s].glyphs[mid].bufferOffset != UINT32_MAX) {
+            alreadyCached = true;
+          }
+          break;
+        }
+        if (pageSlots[s].glyphs[mid].glyphIndex < static_cast<uint32_t>(glyphIdx))
+          left = mid + 1;
+        else
+          right = mid - 1;
+      }
+      if (alreadyCached) break;
+    }
+    if (alreadyCached) continue;
+
+    // Deduplicate within the current page pass
     bool found = false;
     for (uint16_t i = 0; i < glyphCount; i++) {
       if (neededGlyphs[i] == static_cast<uint32_t>(glyphIdx)) {
@@ -297,6 +312,13 @@ int FontDecompressor::prewarmCache(const EpdFontData* fontData, const char* utf8
 
   if (glyphCount == 0) return 0;
 
+  // Allocate the next available slot
+  if (pageSlotCount >= MAX_PAGE_SLOTS) {
+    LOG_ERR("FDC", "All %u page buffer slots full, cannot prewarm fontData=%p", MAX_PAGE_SLOTS, (void*)fontData);
+    return -1;
+  }
+  PageSlot& slot = pageSlots[pageSlotCount];
+
   // Step 2: Compute total buffer size and collect unique groups
   uint32_t totalBytes = 0;
   uint16_t neededGroups[128];

lib/EpdFont/FontDecompressor.h

@@ -7,7 +7,7 @@
 class FontDecompressor {
  public:
   static constexpr uint16_t MAX_PAGE_GLYPHS = 512;
-  static constexpr uint8_t MAX_PAGE_SLOTS = 8;  // Provide enough slots for heavily stylized HTML pages
+  static constexpr uint8_t MAX_PAGE_SLOTS = 4;  // One per font style (R/B/I/BI)
 
   FontDecompressor() = default;
   ~FontDecompressor();