Small code cleanup (#83)

## Summary

* Fix cppcheck low violations
* Remove teardown method on parsers, use destructor
* Code cleanup

.github/workflows/ci.yml

@@ -34,7 +34,7 @@ jobs:
           sudo apt-get install -y clang-format-21
 
       - name: Run cppcheck
-        run: pio check --fail-on-defect medium --fail-on-defect high
+        run: pio check --fail-on-defect low --fail-on-defect medium --fail-on-defect high
 
       - name: Run clang-format
         run: PATH="/usr/lib/llvm-21/bin:$PATH" ./bin/clang-format-fix && git diff --exit-code || (echo "Please run 'bin/clang-format-fix' to fix formatting issues" && exit 1)

lib/Epub/Epub.cpp

@@ -30,24 +30,22 @@ bool Epub::findContentOpfFile(std::string* contentOpfFile) const {
   // Stream read (reusing your existing stream logic)
   if (!readItemContentsToStream(containerPath, containerParser, 512)) {
     Serial.printf("[%lu] [EBP] Could not read META-INF/container.xml\n", millis());
-    containerParser.teardown();
     return false;
   }
 
   // Extract the result
   if (containerParser.fullPath.empty()) {
     Serial.printf("[%lu] [EBP] Could not find valid rootfile in container.xml\n", millis());
-    containerParser.teardown();
     return false;
   }
 
   *contentOpfFile = std::move(containerParser.fullPath);
-
-  containerParser.teardown();
   return true;
 }
 
 bool Epub::parseContentOpf(const std::string& contentOpfFilePath) {
+  Serial.printf("[%lu] [EBP] Parsing content.opf: %s\n", millis(), contentOpfFilePath.c_str());
+
   size_t contentOpfSize;
   if (!getItemSize(contentOpfFilePath, &contentOpfSize)) {
     Serial.printf("[%lu] [EBP] Could not get size of content.opf\n", millis());
@@ -63,7 +61,6 @@ bool Epub::parseContentOpf(const std::string& contentOpfFilePath) {
 
   if (!readItemContentsToStream(contentOpfFilePath, opfParser, 1024)) {
     Serial.printf("[%lu] [EBP] Could not read content.opf\n", millis());
-    opfParser.teardown();
     return false;
   }
 
@@ -84,8 +81,6 @@ bool Epub::parseContentOpf(const std::string& contentOpfFilePath) {
   }
 
   Serial.printf("[%lu] [EBP] Successfully parsed content.opf\n", millis());
-
-  opfParser.teardown();
   return true;
 }
 
@@ -96,6 +91,8 @@ bool Epub::parseTocNcxFile() {
     return false;
   }
 
+  Serial.printf("[%lu] [EBP] Parsing toc ncx file: %s\n", millis(), tocNcxItem.c_str());
+
   size_t tocSize;
   if (!getItemSize(tocNcxItem, &tocSize)) {
     Serial.printf("[%lu] [EBP] Could not get size of toc ncx\n", millis());
@@ -111,22 +108,18 @@ bool Epub::parseTocNcxFile() {
 
   if (!readItemContentsToStream(tocNcxItem, ncxParser, 1024)) {
     Serial.printf("[%lu] [EBP] Could not read toc ncx stream\n", millis());
-    ncxParser.teardown();
     return false;
   }
 
   this->toc = std::move(ncxParser.toc);
 
   Serial.printf("[%lu] [EBP] Parsed %d TOC items\n", millis(), this->toc.size());
-
-  ncxParser.teardown();
   return true;
 }
 
 // load in the meta data for the epub file
 bool Epub::load() {
   Serial.printf("[%lu] [EBP] Loading ePub: %s\n", millis(), filepath.c_str());
-  ZipFile zip("/sd" + filepath);
 
   std::string contentOpfFilePath;
   if (!findContentOpfFile(&contentOpfFilePath)) {
@@ -155,44 +148,20 @@ bool Epub::load() {
 }
 
 void Epub::initializeSpineItemSizes() {
-  setupCacheDir();
+  Serial.printf("[%lu] [EBP] Calculating book size\n", millis());
 
-  size_t spineItemsCount = getSpineItemsCount();
+  const size_t spineItemsCount = getSpineItemsCount();
   size_t cumSpineItemSize = 0;
-  if (SD.exists((getCachePath() + "/spine_size.bin").c_str())) {
-    File f = SD.open((getCachePath() + "/spine_size.bin").c_str());
-    uint8_t data[4];
-    for (size_t i = 0; i < spineItemsCount; i++) {
-      f.read(data, 4);
-      cumSpineItemSize = data[0] | (data[1] << 8) | (data[2] << 16) | (data[3] << 24);
-      cumulativeSpineItemSize.emplace_back(cumSpineItemSize);
-      // Serial.printf("[%lu] [EBP] Loading item %d size %u to %u %u\n", millis(),
-      //     i, cumSpineItemSize, data[1], data[0]);
-    }
-    f.close();
-  } else {
-    File f = SD.open((getCachePath() + "/spine_size.bin").c_str(), FILE_WRITE);
-    uint8_t data[4];
-    // determine size of spine items
-    for (size_t i = 0; i < spineItemsCount; i++) {
-      std::string spineItem = getSpineItem(i);
-      size_t s = 0;
-      getItemSize(spineItem, &s);
-      cumSpineItemSize += s;
-      cumulativeSpineItemSize.emplace_back(cumSpineItemSize);
+  const ZipFile zip("/sd" + filepath);
 
-      // and persist to cache
-      data[0] = cumSpineItemSize & 0xFF;
-      data[1] = (cumSpineItemSize >> 8) & 0xFF;
-      data[2] = (cumSpineItemSize >> 16) & 0xFF;
-      data[3] = (cumSpineItemSize >> 24) & 0xFF;
-      // Serial.printf("[%lu] [EBP] Persisting item %d size %u to %u %u\n", millis(),
-      //     i, cumSpineItemSize, data[1], data[0]);
-      f.write(data, 4);
-    }
-
-    f.close();
+  for (size_t i = 0; i < spineItemsCount; i++) {
+    std::string spineItem = getSpineItem(i);
+    size_t s = 0;
+    getItemSize(zip, spineItem, &s);
+    cumSpineItemSize += s;
+    cumulativeSpineItemSize.emplace_back(cumSpineItemSize);
   }
+
   Serial.printf("[%lu] [EBP] Book size: %lu\n", millis(), cumSpineItemSize);
 }
 
@@ -291,17 +260,31 @@ bool Epub::readItemContentsToStream(const std::string& itemHref, Print& out, con
 
 bool Epub::getItemSize(const std::string& itemHref, size_t* size) const {
   const ZipFile zip("/sd" + filepath);
-  const std::string path = normalisePath(itemHref);
+  return getItemSize(zip, itemHref, size);
+}
 
+bool Epub::getItemSize(const ZipFile& zip, const std::string& itemHref, size_t* size) {
+  const std::string path = normalisePath(itemHref);
   return zip.getInflatedFileSize(path.c_str(), size);
 }
 
 int Epub::getSpineItemsCount() const { return spine.size(); }
 
-size_t Epub::getCumulativeSpineItemSize(const int spineIndex) const { return cumulativeSpineItemSize.at(spineIndex); }
+size_t Epub::getCumulativeSpineItemSize(const int spineIndex) const {
+  if (spineIndex < 0 || spineIndex >= static_cast<int>(cumulativeSpineItemSize.size())) {
+    Serial.printf("[%lu] [EBP] getCumulativeSpineItemSize index:%d is out of range\n", millis(), spineIndex);
+    return 0;
+  }
+  return cumulativeSpineItemSize.at(spineIndex);
+}
 
 std::string& Epub::getSpineItem(const int spineIndex) {
-  if (spineIndex < 0 || spineIndex >= spine.size()) {
+  static std::string emptyString;
+  if (spine.empty()) {
+    Serial.printf("[%lu] [EBP] getSpineItem called but spine is empty\n", millis());
+    return emptyString;
+  }
+  if (spineIndex < 0 || spineIndex >= static_cast<int>(spine.size())) {
     Serial.printf("[%lu] [EBP] getSpineItem index:%d is out of range\n", millis(), spineIndex);
     return spine.at(0).second;
   }
@@ -310,7 +293,12 @@ std::string& Epub::getSpineItem(const int spineIndex) {
 }
 
 EpubTocEntry& Epub::getTocItem(const int tocTndex) {
-  if (tocTndex < 0 || tocTndex >= toc.size()) {
+  static EpubTocEntry emptyEntry("", "", "", 0);
+  if (toc.empty()) {
+    Serial.printf("[%lu] [EBP] getTocItem called but toc is empty\n", millis());
+    return emptyEntry;
+  }
+  if (tocTndex < 0 || tocTndex >= static_cast<int>(toc.size())) {
     Serial.printf("[%lu] [EBP] getTocItem index:%d is out of range\n", millis(), tocTndex);
     return toc.at(0);
   }

lib/Epub/Epub.h

@@ -33,6 +33,7 @@ class Epub {
   bool parseContentOpf(const std::string& contentOpfFilePath);
   bool parseTocNcxFile();
   void initializeSpineItemSizes();
+  static bool getItemSize(const ZipFile& zip, const std::string& itemHref, size_t* size);
 
  public:
   explicit Epub(std::string filepath, const std::string& cacheDir) : filepath(std::move(filepath)) {

lib/Epub/Epub/ParsedText.cpp

@@ -19,14 +19,25 @@ void ParsedText::addWord(std::string word, const EpdFontStyle fontStyle) {
 
 // Consumes data to minimize memory usage
 void ParsedText::layoutAndExtractLines(const GfxRenderer& renderer, const int fontId, const int horizontalMargin,
-                                       const std::function<void(std::shared_ptr<TextBlock>)>& processLine) {
+                                       const std::function<void(std::shared_ptr<TextBlock>)>& processLine,
+                                       const bool includeLastLine) {
   if (words.empty()) {
     return;
   }
 
-  const size_t totalWordCount = words.size();
   const int pageWidth = renderer.getScreenWidth() - horizontalMargin;
   const int spaceWidth = renderer.getSpaceWidth(fontId);
+  const auto wordWidths = calculateWordWidths(renderer, fontId);
+  const auto lineBreakIndices = computeLineBreaks(pageWidth, spaceWidth, wordWidths);
+  const size_t lineCount = includeLastLine ? lineBreakIndices.size() : lineBreakIndices.size() - 1;
+
+  for (size_t i = 0; i < lineCount; ++i) {
+    extractLine(i, pageWidth, spaceWidth, wordWidths, lineBreakIndices, processLine);
+  }
+}
+
+std::vector<uint16_t> ParsedText::calculateWordWidths(const GfxRenderer& renderer, const int fontId) {
+  const size_t totalWordCount = words.size();
 
   std::vector<uint16_t> wordWidths;
   wordWidths.reserve(totalWordCount);
@@ -47,6 +58,13 @@ void ParsedText::layoutAndExtractLines(const GfxRenderer& renderer, const int fo
     std::advance(wordStylesIt, 1);
   }
 
+  return wordWidths;
+}
+
+std::vector<size_t> ParsedText::computeLineBreaks(const int pageWidth, const int spaceWidth,
+                                                  const std::vector<uint16_t>& wordWidths) const {
+  const size_t totalWordCount = words.size();
+
   // DP table to store the minimum badness (cost) of lines starting at index i
   std::vector<int> dp(totalWordCount);
   // 'ans[i]' stores the index 'j' of the *last word* in the optimal line starting at 'i'
@@ -106,66 +124,59 @@ void ParsedText::layoutAndExtractLines(const GfxRenderer& renderer, const int fo
     currentWordIndex = nextBreakIndex;
   }
 
-  // Initialize iterators for consumption
-  auto wordStartIt = words.begin();
-  auto wordStyleStartIt = wordStyles.begin();
-  size_t wordWidthIndex = 0;
-
-  size_t lastBreakAt = 0;
-  for (const size_t lineBreak : lineBreakIndices) {
-    const size_t lineWordCount = lineBreak - lastBreakAt;
-
-    // Calculate end iterators for the range to splice
-    auto wordEndIt = wordStartIt;
-    auto wordStyleEndIt = wordStyleStartIt;
-    std::advance(wordEndIt, lineWordCount);
-    std::advance(wordStyleEndIt, lineWordCount);
-
-    // Calculate total word width for this line
-    int lineWordWidthSum = 0;
-    for (size_t i = 0; i < lineWordCount; ++i) {
-      lineWordWidthSum += wordWidths[wordWidthIndex + i];
-    }
-
-    // Calculate spacing
-    int spareSpace = pageWidth - lineWordWidthSum;
-
-    int spacing = spaceWidth;
-    const bool isLastLine = lineBreak == totalWordCount;
-
-    if (style == TextBlock::JUSTIFIED && !isLastLine && lineWordCount >= 2) {
-      spacing = spareSpace / (lineWordCount - 1);
-    }
-
-    // Calculate initial x position
-    uint16_t xpos = 0;
-    if (style == TextBlock::RIGHT_ALIGN) {
-      xpos = spareSpace - (lineWordCount - 1) * spaceWidth;
-    } else if (style == TextBlock::CENTER_ALIGN) {
-      xpos = (spareSpace - (lineWordCount - 1) * spaceWidth) / 2;
-    }
-
-    // Pre-calculate X positions for words
-    std::list<uint16_t> lineXPos;
-    for (size_t i = 0; i < lineWordCount; ++i) {
-      const uint16_t currentWordWidth = wordWidths[wordWidthIndex + i];
-      lineXPos.push_back(xpos);
-      xpos += currentWordWidth + spacing;
-    }
-
-    // *** CRITICAL STEP: CONSUME DATA USING SPLICE ***
-    std::list<std::string> lineWords;
-    lineWords.splice(lineWords.begin(), words, wordStartIt, wordEndIt);
-    std::list<EpdFontStyle> lineWordStyles;
-    lineWordStyles.splice(lineWordStyles.begin(), wordStyles, wordStyleStartIt, wordStyleEndIt);
-
-    processLine(
-        std::make_shared<TextBlock>(std::move(lineWords), std::move(lineXPos), std::move(lineWordStyles), style));
-
-    // Update pointers/indices for the next line
-    wordStartIt = wordEndIt;
-    wordStyleStartIt = wordStyleEndIt;
-    wordWidthIndex += lineWordCount;
-    lastBreakAt = lineBreak;
-  }
+  return lineBreakIndices;
+}
+
+void ParsedText::extractLine(const size_t breakIndex, const int pageWidth, const int spaceWidth,
+                             const std::vector<uint16_t>& wordWidths, const std::vector<size_t>& lineBreakIndices,
+                             const std::function<void(std::shared_ptr<TextBlock>)>& processLine) {
+  const size_t lineBreak = lineBreakIndices[breakIndex];
+  const size_t lastBreakAt = breakIndex > 0 ? lineBreakIndices[breakIndex - 1] : 0;
+  const size_t lineWordCount = lineBreak - lastBreakAt;
+
+  // Calculate total word width for this line
+  int lineWordWidthSum = 0;
+  for (size_t i = lastBreakAt; i < lineBreak; i++) {
+    lineWordWidthSum += wordWidths[i];
+  }
+
+  // Calculate spacing
+  const int spareSpace = pageWidth - lineWordWidthSum;
+
+  int spacing = spaceWidth;
+  const bool isLastLine = lineBreak == words.size();
+
+  if (style == TextBlock::JUSTIFIED && !isLastLine && lineWordCount >= 2) {
+    spacing = spareSpace / (lineWordCount - 1);
+  }
+
+  // Calculate initial x position
+  uint16_t xpos = 0;
+  if (style == TextBlock::RIGHT_ALIGN) {
+    xpos = spareSpace - (lineWordCount - 1) * spaceWidth;
+  } else if (style == TextBlock::CENTER_ALIGN) {
+    xpos = (spareSpace - (lineWordCount - 1) * spaceWidth) / 2;
+  }
+
+  // Pre-calculate X positions for words
+  std::list<uint16_t> lineXPos;
+  for (size_t i = lastBreakAt; i < lineBreak; i++) {
+    const uint16_t currentWordWidth = wordWidths[i];
+    lineXPos.push_back(xpos);
+    xpos += currentWordWidth + spacing;
+  }
+
+  // Iterators always start at the beginning as we are moving content with splice below
+  auto wordEndIt = words.begin();
+  auto wordStyleEndIt = wordStyles.begin();
+  std::advance(wordEndIt, lineWordCount);
+  std::advance(wordStyleEndIt, lineWordCount);
+
+  // *** CRITICAL STEP: CONSUME DATA USING SPLICE ***
+  std::list<std::string> lineWords;
+  lineWords.splice(lineWords.begin(), words, words.begin(), wordEndIt);
+  std::list<EpdFontStyle> lineWordStyles;
+  lineWordStyles.splice(lineWordStyles.begin(), wordStyles, wordStyles.begin(), wordStyleEndIt);
+
+  processLine(std::make_shared<TextBlock>(std::move(lineWords), std::move(lineXPos), std::move(lineWordStyles), style));
 }

lib/Epub/Epub/ParsedText.h

@@ -2,11 +2,11 @@
 
 #include <EpdFontFamily.h>
 
-#include <cstdint>
 #include <functional>
 #include <list>
 #include <memory>
 #include <string>
+#include <vector>
 
 #include "blocks/TextBlock.h"
 
@@ -18,6 +18,12 @@ class ParsedText {
   TextBlock::BLOCK_STYLE style;
   bool extraParagraphSpacing;
 
+  std::vector<size_t> computeLineBreaks(int pageWidth, int spaceWidth, const std::vector<uint16_t>& wordWidths) const;
+  void extractLine(size_t breakIndex, int pageWidth, int spaceWidth, const std::vector<uint16_t>& wordWidths,
+                   const std::vector<size_t>& lineBreakIndices,
+                   const std::function<void(std::shared_ptr<TextBlock>)>& processLine);
+  std::vector<uint16_t> calculateWordWidths(const GfxRenderer& renderer, int fontId);
+
  public:
   explicit ParsedText(const TextBlock::BLOCK_STYLE style, const bool extraParagraphSpacing)
       : style(style), extraParagraphSpacing(extraParagraphSpacing) {}
@@ -26,7 +32,9 @@ class ParsedText {
   void addWord(std::string word, EpdFontStyle fontStyle);
   void setStyle(const TextBlock::BLOCK_STYLE style) { this->style = style; }
   TextBlock::BLOCK_STYLE getStyle() const { return style; }
+  size_t size() const { return words.size(); }
   bool isEmpty() const { return words.empty(); }
   void layoutAndExtractLines(const GfxRenderer& renderer, int fontId, int horizontalMargin,
-                             const std::function<void(std::shared_ptr<TextBlock>)>& processLine);
+                             const std::function<void(std::shared_ptr<TextBlock>)>& processLine,
+                             bool includeLastLine = true);
 };

lib/Epub/Epub/Section.h

@@ -21,9 +21,10 @@ class Section {
   int currentPage = 0;
 
   explicit Section(const std::shared_ptr<Epub>& epub, const int spineIndex, GfxRenderer& renderer)
-      : epub(epub), spineIndex(spineIndex), renderer(renderer) {
-    cachePath = epub->getCachePath() + "/" + std::to_string(spineIndex);
-  }
+      : epub(epub),
+        spineIndex(spineIndex),
+        renderer(renderer),
+        cachePath(epub->getCachePath() + "/" + std::to_string(spineIndex)) {}
   ~Section() = default;
   bool loadCacheMetadata(int fontId, float lineCompression, int marginTop, int marginRight, int marginBottom,
                          int marginLeft, bool extraParagraphSpacing);

lib/Epub/Epub/parsers/ChapterHtmlSlimParser.cpp

@@ -143,6 +143,17 @@ void XMLCALL ChapterHtmlSlimParser::characterData(void* userData, const XML_Char
 
     self->partWordBuffer[self->partWordBufferIndex++] = s[i];
   }
+
+  // If we have > 750 words buffered up, perform the layout and consume out all but the last line
+  // There should be enough here to build out 1-2 full pages and doing this will free up a lot of
+  // memory.
+  // Spotted when reading Intermezzo, there are some really long text blocks in there.
+  if (self->currentTextBlock->size() > 750) {
+    Serial.printf("[%lu] [EHP] Text block too long, splitting into multiple pages\n", millis());
+    self->currentTextBlock->layoutAndExtractLines(
+        self->renderer, self->fontId, self->marginLeft + self->marginRight,
+        [self](const std::shared_ptr<TextBlock>& textBlock) { self->addLineToPage(textBlock); }, false);
+  }
 }
 
 void XMLCALL ChapterHtmlSlimParser::endElement(void* userData, const XML_Char* name) {

lib/Epub/Epub/parsers/ContainerParser.cpp

@@ -14,12 +14,11 @@ bool ContainerParser::setup() {
   return true;
 }
 
-bool ContainerParser::teardown() {
+ContainerParser::~ContainerParser() {
   if (parser) {
     XML_ParserFree(parser);
     parser = nullptr;
   }
-  return true;
 }
 
 size_t ContainerParser::write(const uint8_t data) { return write(&data, 1); }

lib/Epub/Epub/parsers/ContainerParser.h

@@ -23,9 +23,9 @@ class ContainerParser final : public Print {
   std::string fullPath;
 
   explicit ContainerParser(const size_t xmlSize) : remainingSize(xmlSize) {}
+  ~ContainerParser() override;
 
   bool setup();
-  bool teardown();
 
   size_t write(uint8_t) override;
   size_t write(const uint8_t* buffer, size_t size) override;

lib/Epub/Epub/parsers/ContentOpfParser.cpp

@@ -4,7 +4,7 @@
 #include <ZipFile.h>
 
 namespace {
-constexpr const char MEDIA_TYPE_NCX[] = "application/x-dtbncx+xml";
+constexpr char MEDIA_TYPE_NCX[] = "application/x-dtbncx+xml";
 }
 
 bool ContentOpfParser::setup() {
@@ -20,12 +20,11 @@ bool ContentOpfParser::setup() {
   return true;
 }
 
-bool ContentOpfParser::teardown() {
+ContentOpfParser::~ContentOpfParser() {
   if (parser) {
     XML_ParserFree(parser);
     parser = nullptr;
   }
-  return true;
 }
 
 size_t ContentOpfParser::write(const uint8_t data) { return write(&data, 1); }

lib/Epub/Epub/parsers/ContentOpfParser.h

@@ -34,9 +34,9 @@ class ContentOpfParser final : public Print {
 
   explicit ContentOpfParser(const std::string& baseContentPath, const size_t xmlSize)
       : baseContentPath(baseContentPath), remainingSize(xmlSize) {}
+  ~ContentOpfParser() override;
 
   bool setup();
-  bool teardown();
 
   size_t write(uint8_t) override;
   size_t write(const uint8_t* buffer, size_t size) override;

lib/Epub/Epub/parsers/TocNcxParser.cpp

@@ -1,5 +1,6 @@
 #include "TocNcxParser.h"
 
+#include <Esp.h>
 #include <HardwareSerial.h>
 
 bool TocNcxParser::setup() {
@@ -15,12 +16,11 @@ bool TocNcxParser::setup() {
   return true;
 }
 
-bool TocNcxParser::teardown() {
+TocNcxParser::~TocNcxParser() {
   if (parser) {
     XML_ParserFree(parser);
     parser = nullptr;
   }
-  return true;
 }
 
 size_t TocNcxParser::write(const uint8_t data) { return write(&data, 1); }

lib/Epub/Epub/parsers/TocNcxParser.h

@@ -28,9 +28,9 @@ class TocNcxParser final : public Print {
 
   explicit TocNcxParser(const std::string& baseContentPath, const size_t xmlSize)
       : baseContentPath(baseContentPath), remainingSize(xmlSize) {}
+  ~TocNcxParser() override;
 
   bool setup();
-  bool teardown();
 
   size_t write(uint8_t) override;
   size_t write(const uint8_t* buffer, size_t size) override;

lib/GfxRenderer/GfxRenderer.cpp

@@ -136,6 +136,13 @@ void GfxRenderer::drawBitmap(const Bitmap& bitmap, const int x, const int y, con
   auto* outputRow = static_cast<uint8_t*>(malloc(outputRowSize));
   auto* rowBytes = static_cast<uint8_t*>(malloc(bitmap.getRowBytes()));
 
+  if (!outputRow || !rowBytes) {
+    Serial.printf("[%lu] [GFX] !! Failed to allocate BMP row buffers\n", millis());
+    free(outputRow);
+    free(rowBytes);
+    return;
+  }
+
   for (int bmpY = 0; bmpY < bitmap.getHeight(); bmpY++) {
     // The BMP's (0, 0) is the bottom-left corner (if the height is positive, top-left if negative).
     // Screen's (0, 0) is the top-left corner.
@@ -183,6 +190,10 @@ void GfxRenderer::clearScreen(const uint8_t color) const { einkDisplay.clearScre
 
 void GfxRenderer::invertScreen() const {
   uint8_t* buffer = einkDisplay.getFrameBuffer();
+  if (!buffer) {
+    Serial.printf("[%lu] [GFX] !! No framebuffer in invertScreen\n", millis());
+    return;
+  }
   for (int i = 0; i < EInkDisplay::BUFFER_SIZE; i++) {
     buffer[i] = ~buffer[i];
   }
@@ -256,6 +267,10 @@ void GfxRenderer::freeBwBufferChunks() {
  */
 void GfxRenderer::storeBwBuffer() {
   const uint8_t* frameBuffer = einkDisplay.getFrameBuffer();
+  if (!frameBuffer) {
+    Serial.printf("[%lu] [GFX] !! No framebuffer in storeBwBuffer\n", millis());
+    return;
+  }
 
   // Allocate and copy each chunk
   for (size_t i = 0; i < BW_BUFFER_NUM_CHUNKS; i++) {
@@ -306,6 +321,12 @@ void GfxRenderer::restoreBwBuffer() {
   }
 
   uint8_t* frameBuffer = einkDisplay.getFrameBuffer();
+  if (!frameBuffer) {
+    Serial.printf("[%lu] [GFX] !! No framebuffer in restoreBwBuffer\n", millis());
+    freeBwBufferChunks();
+    return;
+  }
+
   for (size_t i = 0; i < BW_BUFFER_NUM_CHUNKS; i++) {
     // Check if chunk is missing
     if (!bwBufferChunks[i]) {

lib/ZipFile/ZipFile.cpp

@@ -27,31 +27,28 @@ bool inflateOneShot(const uint8_t* inputBuf, const size_t deflatedSize, uint8_t*
   return true;
 }
 
-bool ZipFile::loadFileStat(const char* filename, mz_zip_archive_file_stat* fileStat) const {
-  mz_zip_archive zipArchive = {};
-  const bool status = mz_zip_reader_init_file(&zipArchive, filePath.c_str(), 0);
+ZipFile::ZipFile(std::string filePath) : filePath(std::move(filePath)) {
+  const bool status = mz_zip_reader_init_file(&zipArchive, this->filePath.c_str(), 0);
 
   if (!status) {
-    Serial.printf("[%lu] [ZIP] mz_zip_reader_init_file() failed! Error: %s\n", millis(),
+    Serial.printf("[%lu] [ZIP] mz_zip_reader_init_file() failed for %s! Error: %s\n", millis(), this->filePath.c_str(),
                   mz_zip_get_error_string(zipArchive.m_last_error));
-    return false;
   }
+}
 
+bool ZipFile::loadFileStat(const char* filename, mz_zip_archive_file_stat* fileStat) const {
   // find the file
   mz_uint32 fileIndex = 0;
   if (!mz_zip_reader_locate_file_v2(&zipArchive, filename, nullptr, 0, &fileIndex)) {
     Serial.printf("[%lu] [ZIP] Could not find file %s\n", millis(), filename);
-    mz_zip_reader_end(&zipArchive);
     return false;
   }
 
   if (!mz_zip_reader_file_stat(&zipArchive, fileIndex, fileStat)) {
     Serial.printf("[%lu] [ZIP] mz_zip_reader_file_stat() failed! Error: %s\n", millis(),
                   mz_zip_get_error_string(zipArchive.m_last_error));
-    mz_zip_reader_end(&zipArchive);
     return false;
   }
-  mz_zip_reader_end(&zipArchive);
   return true;
 }
 
@@ -118,6 +115,11 @@ uint8_t* ZipFile::readFileToMemory(const char* filename, size_t* size, const boo
   const auto inflatedDataSize = static_cast<size_t>(fileStat.m_uncomp_size);
   const auto dataSize = trailingNullByte ? inflatedDataSize + 1 : inflatedDataSize;
   const auto data = static_cast<uint8_t*>(malloc(dataSize));
+  if (data == nullptr) {
+    Serial.printf("[%lu] [ZIP] Failed to allocate memory for output buffer (%zu bytes)\n", millis(), dataSize);
+    fclose(file);
+    return nullptr;
+  }
 
   if (fileStat.m_method == MZ_NO_COMPRESSION) {
     // no deflation, just read content

lib/ZipFile/ZipFile.h

@@ -1,19 +1,19 @@
 #pragma once
 #include <Print.h>
 
-#include <functional>
 #include <string>
 
 #include "miniz.h"
 
 class ZipFile {
   std::string filePath;
+  mutable mz_zip_archive zipArchive = {};
   bool loadFileStat(const char* filename, mz_zip_archive_file_stat* fileStat) const;
   long getDataOffset(const mz_zip_archive_file_stat& fileStat) const;
 
  public:
-  explicit ZipFile(std::string filePath) : filePath(std::move(filePath)) {}
-  ~ZipFile() = default;
+  explicit ZipFile(std::string filePath);
+  ~ZipFile() { mz_zip_reader_end(&zipArchive); }
   bool getInflatedFileSize(const char* filename, size_t* size) const;
   uint8_t* readFileToMemory(const char* filename, size_t* size = nullptr, bool trailingNullByte = false) const;
   bool readFileToStream(const char* filename, Print& out, size_t chunkSize) const;

platformio.ini

@@ -9,8 +9,8 @@ framework = arduino
 monitor_speed = 115200
 upload_speed = 921600
 check_tool = cppcheck
+check_flags = --enable=all --suppress=missingIncludeSystem --suppress=unusedFunction --suppress=unmatchedSuppression --inline-suppr
 check_skip_packages = yes
-check_severity = medium, high
 
 board_upload.flash_size = 16MB
 board_upload.maximum_size = 16777216

src/WifiCredentialStore.cpp

@@ -111,12 +111,12 @@ bool WifiCredentialStore::loadFromFile() {
 
 bool WifiCredentialStore::addCredential(const std::string& ssid, const std::string& password) {
   // Check if this SSID already exists and update it
-  for (auto& cred : credentials) {
-    if (cred.ssid == ssid) {
-      cred.password = password;
-      Serial.printf("[%lu] [WCS] Updated credentials for: %s\n", millis(), ssid.c_str());
-      return saveToFile();
-    }
+  const auto cred = find_if(credentials.begin(), credentials.end(),
+                            [&ssid](const WifiCredential& cred) { return cred.ssid == ssid; });
+  if (cred != credentials.end()) {
+    cred->password = password;
+    Serial.printf("[%lu] [WCS] Updated credentials for: %s\n", millis(), ssid.c_str());
+    return saveToFile();
   }
 
   // Check if we've reached the limit
@@ -132,22 +132,24 @@ bool WifiCredentialStore::addCredential(const std::string& ssid, const std::stri
 }
 
 bool WifiCredentialStore::removeCredential(const std::string& ssid) {
-  for (auto it = credentials.begin(); it != credentials.end(); ++it) {
-    if (it->ssid == ssid) {
-      credentials.erase(it);
-      Serial.printf("[%lu] [WCS] Removed credentials for: %s\n", millis(), ssid.c_str());
-      return saveToFile();
-    }
+  const auto cred = find_if(credentials.begin(), credentials.end(),
+                            [&ssid](const WifiCredential& cred) { return cred.ssid == ssid; });
+  if (cred != credentials.end()) {
+    credentials.erase(cred);
+    Serial.printf("[%lu] [WCS] Removed credentials for: %s\n", millis(), ssid.c_str());
+    return saveToFile();
   }
   return false;  // Not found
 }
 
 const WifiCredential* WifiCredentialStore::findCredential(const std::string& ssid) const {
-  for (const auto& cred : credentials) {
-    if (cred.ssid == ssid) {
-      return &cred;
-    }
+  const auto cred = find_if(credentials.begin(), credentials.end(),
+                            [&ssid](const WifiCredential& cred) { return cred.ssid == ssid; });
+
+  if (cred != credentials.end()) {
+    return &*cred;
   }
+
   return nullptr;
 }
 

src/activities/boot_sleep/SleepActivity.cpp

@@ -1,11 +1,11 @@
 #include "SleepActivity.h"
 
 #include <GfxRenderer.h>
+#include <SD.h>
 
 #include <vector>
 
 #include "CrossPointSettings.h"
-#include "SD.h"
 #include "config.h"
 #include "images/CrossLarge.h"
 

src/activities/network/CrossPointWebServerActivity.cpp

@@ -217,8 +217,7 @@ void CrossPointWebServerActivity::render() const {
 }
 
 void CrossPointWebServerActivity::renderServerRunning() const {
-  const auto pageWidth = GfxRenderer::getScreenWidth();
-  const auto pageHeight = GfxRenderer::getScreenHeight();
+  const auto pageHeight = renderer.getScreenHeight();
   const auto height = renderer.getLineHeight(UI_FONT_ID);
   const auto top = (pageHeight - height * 5) / 2;
 
@@ -226,7 +225,7 @@ void CrossPointWebServerActivity::renderServerRunning() const {
 
   std::string ssidInfo = "Network: " + connectedSSID;
   if (ssidInfo.length() > 28) {
-    ssidInfo = ssidInfo.substr(0, 25) + "...";
+    ssidInfo.replace(25, ssidInfo.length() - 25, "...");
   }
   renderer.drawCenteredText(UI_FONT_ID, top + 10, ssidInfo.c_str(), true, REGULAR);
 

src/activities/network/WifiSelectionActivity.cpp

@@ -138,6 +138,7 @@ void WifiSelectionActivity::processWifiScanResults() {
   // Convert map to vector
   networks.clear();
   for (const auto& pair : uniqueNetworks) {
+    // cppcheck-suppress useStlAlgorithm
     networks.push_back(pair.second);
   }
 
@@ -334,11 +335,10 @@ void WifiSelectionActivity::loop() {
         // User chose "Yes" - forget the network
         WIFI_STORE.removeCredential(selectedSSID);
         // Update the network list to reflect the change
-        for (auto& network : networks) {
-          if (network.ssid == selectedSSID) {
-            network.hasSavedPassword = false;
-            break;
-          }
+        const auto network = find_if(networks.begin(), networks.end(),
+                                     [this](const WifiNetworkInfo& net) { return net.ssid == selectedSSID; });
+        if (network != networks.end()) {
+          network->hasSavedPassword = false;
         }
       }
       // Go back to network list
@@ -468,8 +468,8 @@ void WifiSelectionActivity::render() const {
 }
 
 void WifiSelectionActivity::renderNetworkList() const {
-  const auto pageWidth = GfxRenderer::getScreenWidth();
-  const auto pageHeight = GfxRenderer::getScreenHeight();
+  const auto pageWidth = renderer.getScreenWidth();
+  const auto pageHeight = renderer.getScreenHeight();
 
   // Draw header
   renderer.drawCenteredText(READER_FONT_ID, 10, "WiFi Networks", true, BOLD);
@@ -506,7 +506,7 @@ void WifiSelectionActivity::renderNetworkList() const {
       // Draw network name (truncate if too long)
       std::string displayName = network.ssid;
       if (displayName.length() > 16) {
-        displayName = displayName.substr(0, 13) + "...";
+        displayName.replace(13, displayName.length() - 13, "...");
       }
       renderer.drawText(UI_FONT_ID, 20, networkY, displayName.c_str());
 
@@ -544,15 +544,13 @@ void WifiSelectionActivity::renderNetworkList() const {
 }
 
 void WifiSelectionActivity::renderPasswordEntry() const {
-  const auto pageHeight = GfxRenderer::getScreenHeight();
-
   // Draw header
   renderer.drawCenteredText(READER_FONT_ID, 5, "WiFi Password", true, BOLD);
 
   // Draw network name with good spacing from header
   std::string networkInfo = "Network: " + selectedSSID;
   if (networkInfo.length() > 30) {
-    networkInfo = networkInfo.substr(0, 27) + "...";
+    networkInfo.replace(27, networkInfo.length() - 27, "...");
   }
   renderer.drawCenteredText(UI_FONT_ID, 38, networkInfo.c_str(), true, REGULAR);
 
@@ -563,7 +561,7 @@ void WifiSelectionActivity::renderPasswordEntry() const {
 }
 
 void WifiSelectionActivity::renderConnecting() const {
-  const auto pageHeight = GfxRenderer::getScreenHeight();
+  const auto pageHeight = renderer.getScreenHeight();
   const auto height = renderer.getLineHeight(UI_FONT_ID);
   const auto top = (pageHeight - height) / 2;
 
@@ -574,15 +572,14 @@ void WifiSelectionActivity::renderConnecting() const {
 
     std::string ssidInfo = "to " + selectedSSID;
     if (ssidInfo.length() > 25) {
-      ssidInfo = ssidInfo.substr(0, 22) + "...";
+      ssidInfo.replace(22, ssidInfo.length() - 22, "...");
     }
     renderer.drawCenteredText(UI_FONT_ID, top, ssidInfo.c_str(), true, REGULAR);
   }
 }
 
 void WifiSelectionActivity::renderConnected() const {
-  const auto pageWidth = GfxRenderer::getScreenWidth();
-  const auto pageHeight = GfxRenderer::getScreenHeight();
+  const auto pageHeight = renderer.getScreenHeight();
   const auto height = renderer.getLineHeight(UI_FONT_ID);
   const auto top = (pageHeight - height * 4) / 2;
 
@@ -590,7 +587,7 @@ void WifiSelectionActivity::renderConnected() const {
 
   std::string ssidInfo = "Network: " + selectedSSID;
   if (ssidInfo.length() > 28) {
-    ssidInfo = ssidInfo.substr(0, 25) + "...";
+    ssidInfo.replace(25, ssidInfo.length() - 25, "...");
   }
   renderer.drawCenteredText(UI_FONT_ID, top + 10, ssidInfo.c_str(), true, REGULAR);
 
@@ -601,8 +598,8 @@ void WifiSelectionActivity::renderConnected() const {
 }
 
 void WifiSelectionActivity::renderSavePrompt() const {
-  const auto pageWidth = GfxRenderer::getScreenWidth();
-  const auto pageHeight = GfxRenderer::getScreenHeight();
+  const auto pageWidth = renderer.getScreenWidth();
+  const auto pageHeight = renderer.getScreenHeight();
   const auto height = renderer.getLineHeight(UI_FONT_ID);
   const auto top = (pageHeight - height * 3) / 2;
 
@@ -610,7 +607,7 @@ void WifiSelectionActivity::renderSavePrompt() const {
 
   std::string ssidInfo = "Network: " + selectedSSID;
   if (ssidInfo.length() > 28) {
-    ssidInfo = ssidInfo.substr(0, 25) + "...";
+    ssidInfo.replace(25, ssidInfo.length() - 25, "...");
   }
   renderer.drawCenteredText(UI_FONT_ID, top, ssidInfo.c_str(), true, REGULAR);
 
@@ -641,7 +638,7 @@ void WifiSelectionActivity::renderSavePrompt() const {
 }
 
 void WifiSelectionActivity::renderConnectionFailed() const {
-  const auto pageHeight = GfxRenderer::getScreenHeight();
+  const auto pageHeight = renderer.getScreenHeight();
   const auto height = renderer.getLineHeight(UI_FONT_ID);
   const auto top = (pageHeight - height * 2) / 2;
 
@@ -651,8 +648,8 @@ void WifiSelectionActivity::renderConnectionFailed() const {
 }
 
 void WifiSelectionActivity::renderForgetPrompt() const {
-  const auto pageWidth = GfxRenderer::getScreenWidth();
-  const auto pageHeight = GfxRenderer::getScreenHeight();
+  const auto pageWidth = renderer.getScreenWidth();
+  const auto pageHeight = renderer.getScreenHeight();
   const auto height = renderer.getLineHeight(UI_FONT_ID);
   const auto top = (pageHeight - height * 3) / 2;
 
@@ -660,7 +657,7 @@ void WifiSelectionActivity::renderForgetPrompt() const {
 
   std::string ssidInfo = "Network: " + selectedSSID;
   if (ssidInfo.length() > 28) {
-    ssidInfo = ssidInfo.substr(0, 25) + "...";
+    ssidInfo.replace(25, ssidInfo.length() - 25, "...");
   }
   renderer.drawCenteredText(UI_FONT_ID, top, ssidInfo.c_str(), true, REGULAR);
 

src/activities/network/server/CrossPointWebServer.cpp

@@ -383,9 +383,7 @@ void CrossPointWebServer::handleFileList() {
       // Folders come first
       if (a.isDirectory != b.isDirectory) return a.isDirectory > b.isDirectory;
       // Then sort by epub status (epubs first among files)
-      if (!a.isDirectory && !b.isDirectory) {
-        if (a.isEpub != b.isEpub) return a.isEpub > b.isEpub;
-      }
+      if (a.isEpub != b.isEpub) return a.isEpub > b.isEpub;
       // Then alphabetically
       return a.name < b.name;
     });
@@ -513,13 +511,6 @@ void CrossPointWebServer::handleUpload() {
     Serial.printf("[%lu] [WEB] [UPLOAD] START: %s to path: %s\n", millis(), uploadFileName.c_str(), uploadPath.c_str());
     Serial.printf("[%lu] [WEB] [UPLOAD] Free heap: %d bytes\n", millis(), ESP.getFreeHeap());
 
-    // Validate file extension
-    if (!isEpubFile(uploadFileName)) {
-      uploadError = "Only .epub files are allowed";
-      Serial.printf("[%lu] [WEB] [UPLOAD] REJECTED - not an epub file\n", millis());
-      return;
-    }
-
     // Create file path
     String filePath = uploadPath;
     if (!filePath.endsWith("/")) filePath += "/";

src/activities/reader/EpubReaderActivity.cpp

@@ -383,7 +383,7 @@ void EpubReaderActivity::renderStatusBar() const {
     title = tocItem.title;
     titleWidth = renderer.getTextWidth(SMALL_FONT_ID, title.c_str());
     while (titleWidth > availableTextWidth && title.length() > 11) {
-      title = title.substr(0, title.length() - 8) + "...";
+      title.replace(title.length() - 8, 8, "...");
       titleWidth = renderer.getTextWidth(SMALL_FONT_ID, title.c_str());
     }
   }

src/activities/reader/FileSelectionActivity.cpp

@@ -93,7 +93,7 @@ void FileSelectionActivity::loop() {
     }
   } else if (inputManager.wasPressed(InputManager::BTN_BACK)) {
     if (basepath != "/") {
-      basepath = basepath.substr(0, basepath.rfind('/'));
+      basepath.replace(basepath.find_last_of('/'), std::string::npos, "");
       if (basepath.empty()) basepath = "/";
       loadFiles();
       updateRequired = true;

src/activities/util/KeyboardEntryActivity.cpp

@@ -20,7 +20,7 @@ KeyboardEntryActivity::KeyboardEntryActivity(GfxRenderer& renderer, InputManager
 void KeyboardEntryActivity::setText(const std::string& newText) {
   text = newText;
   if (maxLength > 0 && text.length() > maxLength) {
-    text = text.substr(0, maxLength);
+    text.resize(maxLength);
   }
 }
 

src/html/FilesPageFooter.html

@@ -3,15 +3,15 @@
       CrossPoint E-Reader • Open Source
     </p>
   </div>
-  
+
   <!-- Upload Modal -->
   <div class="modal-overlay" id="uploadModal">
     <div class="modal">
       <button class="modal-close" onclick="closeUploadModal()">&times;</button>
-      <h3>📤 Upload eBook</h3>
+      <h3>📤 Upload file</h3>
       <div class="upload-form">
-        <p class="file-info">Select an .epub file to upload to <strong id="uploadPathDisplay"></strong></p>
-        <input type="file" id="fileInput" accept=".epub" onchange="validateFile()">
+        <p class="file-info">Select a file to upload to <strong id="uploadPathDisplay"></strong></p>
+        <input type="file" id="fileInput" onchange="validateFile()">
         <button id="uploadBtn" class="upload-btn" onclick="uploadFile()" disabled>Upload</button>
         <div id="progress-container">
           <div id="progress-bar"><div id="progress-fill"></div></div>
@@ -20,7 +20,7 @@
       </div>
     </div>
   </div>
-  
+
   <!-- New Folder Modal -->
   <div class="modal-overlay" id="folderModal">
     <div class="modal">
@@ -33,7 +33,7 @@
       </div>
     </div>
   </div>
-  
+
   <!-- Delete Confirmation Modal -->
   <div class="modal-overlay" id="deleteModal">
     <div class="modal">
@@ -50,7 +50,7 @@
       </div>
     </div>
   </div>
-  
+
   <script>
     // Modal functions
     function openUploadModal() {
@@ -58,7 +58,7 @@
       document.getElementById('uploadPathDisplay').textContent = currentPath === '/' ? '/ 🏠' : currentPath;
       document.getElementById('uploadModal').classList.add('open');
     }
-    
+
     function closeUploadModal() {
       document.getElementById('uploadModal').classList.remove('open');
       document.getElementById('fileInput').value = '';
@@ -67,18 +67,18 @@
       document.getElementById('progress-fill').style.width = '0%';
       document.getElementById('progress-fill').style.backgroundColor = '#27ae60';
     }
-    
+
     function openFolderModal() {
       const currentPath = document.getElementById('currentPath').value;
       document.getElementById('folderPathDisplay').textContent = currentPath === '/' ? '/ 🏠' : currentPath;
       document.getElementById('folderModal').classList.add('open');
       document.getElementById('folderName').value = '';
     }
-    
+
     function closeFolderModal() {
       document.getElementById('folderModal').classList.remove('open');
     }
-    
+
     // Close modals when clicking overlay
     document.querySelectorAll('.modal-overlay').forEach(function(overlay) {
       overlay.addEventListener('click', function(e) {
@@ -87,58 +87,40 @@
         }
       });
     });
-    
+
     function validateFile() {
       const fileInput = document.getElementById('fileInput');
       const uploadBtn = document.getElementById('uploadBtn');
       const file = fileInput.files[0];
-      
-      if (file) {
-        const fileName = file.name.toLowerCase();
-        if (!fileName.endsWith('.epub')) {
-          alert('Only .epub files are allowed!');
-          fileInput.value = '';
-          uploadBtn.disabled = true;
-          return;
-        }
-        uploadBtn.disabled = false;
-      } else {
-        uploadBtn.disabled = true;
-      }
+      uploadBtn.disabled = !file;
     }
-    
+
     function uploadFile() {
       const fileInput = document.getElementById('fileInput');
       const file = fileInput.files[0];
       const currentPath = document.getElementById('currentPath').value;
-      
+
       if (!file) {
         alert('Please select a file first!');
         return;
       }
-      
-      const fileName = file.name.toLowerCase();
-      if (!fileName.endsWith('.epub')) {
-        alert('Only .epub files are allowed!');
-        return;
-      }
-      
+
       const formData = new FormData();
       formData.append('file', file);
-      
+
       const progressContainer = document.getElementById('progress-container');
       const progressFill = document.getElementById('progress-fill');
       const progressText = document.getElementById('progress-text');
       const uploadBtn = document.getElementById('uploadBtn');
-      
+
       progressContainer.style.display = 'block';
       uploadBtn.disabled = true;
-      
+
       const xhr = new XMLHttpRequest();
       // Include path as query parameter since multipart form data doesn't make
       // form fields available until after file upload completes
       xhr.open('POST', '/upload?path=' + encodeURIComponent(currentPath), true);
-      
+
       xhr.upload.onprogress = function(e) {
         if (e.lengthComputable) {
           const percent = Math.round((e.loaded / e.total) * 100);
@@ -146,7 +128,7 @@
           progressText.textContent = 'Uploading: ' + percent + '%';
         }
       };
-      
+
       xhr.onload = function() {
         if (xhr.status === 200) {
           progressText.textContent = 'Upload complete!';
@@ -159,39 +141,39 @@
           uploadBtn.disabled = false;
         }
       };
-      
+
       xhr.onerror = function() {
         progressText.textContent = 'Upload failed - network error';
         progressFill.style.backgroundColor = '#e74c3c';
         uploadBtn.disabled = false;
       };
-      
+
       xhr.send(formData);
     }
-    
+
     function createFolder() {
       const folderName = document.getElementById('folderName').value.trim();
       const currentPath = document.getElementById('currentPath').value;
-      
+
       if (!folderName) {
         alert('Please enter a folder name!');
         return;
       }
-      
+
       // Validate folder name (no special characters except underscore and hyphen)
       const validName = /^[a-zA-Z0-9_\-]+$/.test(folderName);
       if (!validName) {
         alert('Folder name can only contain letters, numbers, underscores, and hyphens.');
         return;
       }
-      
+
       const formData = new FormData();
       formData.append('name', folderName);
       formData.append('path', currentPath);
-      
+
       const xhr = new XMLHttpRequest();
       xhr.open('POST', '/mkdir', true);
-      
+
       xhr.onload = function() {
         if (xhr.status === 200) {
           window.location.reload();
@@ -199,14 +181,14 @@
           alert('Failed to create folder: ' + xhr.responseText);
         }
       };
-      
+
       xhr.onerror = function() {
         alert('Failed to create folder - network error');
       };
-      
+
       xhr.send(formData);
     }
-    
+
     // Delete functions
     function openDeleteModal(name, path, isFolder) {
       document.getElementById('deleteItemName').textContent = (isFolder ? '📁 ' : '📄 ') + name;
@@ -214,22 +196,22 @@
       document.getElementById('deleteItemType').value = isFolder ? 'folder' : 'file';
       document.getElementById('deleteModal').classList.add('open');
     }
-    
+
     function closeDeleteModal() {
       document.getElementById('deleteModal').classList.remove('open');
     }
-    
+
     function confirmDelete() {
       const path = document.getElementById('deleteItemPath').value;
       const itemType = document.getElementById('deleteItemType').value;
-      
+
       const formData = new FormData();
       formData.append('path', path);
       formData.append('type', itemType);
-      
+
       const xhr = new XMLHttpRequest();
       xhr.open('POST', '/delete', true);
-      
+
       xhr.onload = function() {
         if (xhr.status === 200) {
           window.location.reload();
@@ -238,12 +220,12 @@
           closeDeleteModal();
         }
       };
-      
+
       xhr.onerror = function() {
         alert('Failed to delete - network error');
         closeDeleteModal();
       };
-      
+
       xhr.send(formData);
     }
   </script>

src/main.cpp

@@ -5,7 +5,6 @@
 #include <InputManager.h>
 #include <SD.h>
 #include <SPI.h>
-#include <WiFi.h>
 #include <builtinFonts/bookerly_2b.h>
 #include <builtinFonts/bookerly_bold_2b.h>
 #include <builtinFonts/bookerly_bold_italic_2b.h>
@@ -203,20 +202,18 @@ void setup() {
 }
 
 void loop() {
-  static unsigned long lastLoopTime = 0;
   static unsigned long maxLoopDuration = 0;
-
-  unsigned long loopStartTime = millis();
-
+  const unsigned long loopStartTime = millis();
   static unsigned long lastMemPrint = 0;
+
+  inputManager.update();
+
   if (Serial && millis() - lastMemPrint >= 10000) {
     Serial.printf("[%lu] [MEM] Free: %d bytes, Total: %d bytes, Min Free: %d bytes\n", millis(), ESP.getFreeHeap(),
                   ESP.getHeapSize(), ESP.getMinFreeHeap());
     lastMemPrint = millis();
   }
 
-  inputManager.update();
-
   // Check for any user activity (button press or release)
   static unsigned long lastActivityTime = millis();
   if (inputManager.wasAnyPressed() || inputManager.wasAnyReleased()) {
@@ -237,13 +234,13 @@ void loop() {
     return;
   }
 
-  unsigned long activityStartTime = millis();
+  const unsigned long activityStartTime = millis();
   if (currentActivity) {
     currentActivity->loop();
   }
-  unsigned long activityDuration = millis() - activityStartTime;
+  const unsigned long activityDuration = millis() - activityStartTime;
 
-  unsigned long loopDuration = millis() - loopStartTime;
+  const unsigned long loopDuration = millis() - loopStartTime;
   if (loopDuration > maxLoopDuration) {
     maxLoopDuration = loopDuration;
     if (maxLoopDuration > 50) {
@@ -252,8 +249,6 @@ void loop() {
     }
   }
 
-  lastLoopTime = loopStartTime;
-
   // Add delay at the end of the loop to prevent tight spinning
   // When an activity requests skip loop delay (e.g., webserver running), use yield() for faster response
   // Otherwise, use longer delay to save power