Integrate PT 1455

lib/Epub/Epub/Section.h

@@ -23,6 +23,15 @@ class Section {
                               bool embeddedStyle, uint8_t imageRendering);
   uint32_t onPageComplete(std::unique_ptr<Page> page);
 
+  struct TocBoundary {
+    int tocIndex = 0;
+    uint16_t startPage = 0;
+  };
+  std::vector<TocBoundary> tocBoundaries;
+
+  void buildTocBoundaries(const std::vector<std::pair<std::string, uint16_t>>& anchors);
+  void buildTocBoundariesFromFile(FsFile& f);
+
  public:
   uint16_t pageCount = 0;
   int currentPage = 0;
@@ -42,6 +51,19 @@ class Section {
                          uint8_t imageRendering, const std::function<void(int)>& progressFn = nullptr);
   std::unique_ptr<Page> loadPageFromSectionFile();
 
+  // Given a page in this section, return the TOC index for that page.
+  int getTocIndexForPage(int page) const;
+  // Given a TOC index, return the start page in this section.
+  // Returns nullopt if the TOC index doesn't map to a boundary in this spine (e.g. belongs to a different spine).
+  std::optional<int> getPageForTocIndex(int tocIndex) const;
+
+  struct TocPageRange {
+    int startPage;  // inclusive
+    int endPage;    // exclusive
+  };
+  // Returns the page range [start, end) within this spine that belongs to the given TOC index.
+  std::optional<TocPageRange> getPageRangeForTocIndex(int tocIndex) const;
+
   // Look up the page number for an anchor id from the section cache file.
   std::optional<uint16_t> getPageForAnchor(const std::string& anchor) const;