New feature: SDCARD_SORT_ALPHA

Marlin/cardreader.h

@@ -69,6 +69,16 @@ public:
   void updir();
   void setroot();
 
+  #if ENABLED(SDCARD_SORT_ALPHA)
+    void presort();
+    void getfilename_sorted(const uint16_t nr);
+    #if ENABLED(SDSORT_GCODE)
+      FORCE_INLINE void setSortOn(bool b) { sort_alpha = b; presort(); }
+      FORCE_INLINE void setSortFolders(int i) { sort_folders = i; presort(); }
+      //FORCE_INLINE void setSortReverse(bool b) { sort_reverse = b; }
+    #endif
+  #endif
+
   FORCE_INLINE void pauseSDPrint() { sdprinting = false; }
   FORCE_INLINE bool isFileOpen() { return file.isOpen(); }
   FORCE_INLINE bool eof() { return sdpos >= filesize; }
@@ -84,6 +94,38 @@ public:
 private:
   SdFile root, *curDir, workDir, workDirParents[MAX_DIR_DEPTH];
   uint8_t workDirDepth;
+
+  // Sort files and folders alphabetically.
+  #if ENABLED(SDCARD_SORT_ALPHA)
+    uint16_t sort_count;        // Count of sorted items in the current directory
+    #if ENABLED(SDSORT_GCODE)
+      bool sort_alpha;          // Flag to enable / disable the feature
+      int sort_folders;         // Flag to enable / disable folder sorting
+      //bool sort_reverse;      // Flag to enable / disable reverse sorting
+    #endif
+
+    uint8_t sort_order[SDSORT_LIMIT];
+
+    // Cache filenames to speed up SD menus.
+    #if ENABLED(SDSORT_USES_RAM)
+
+      // If using dynamic ram for names, allocate on the heap.
+      #if ENABLED(SDSORT_CACHE_NAMES)
+        char sortshort[SDSORT_LIMIT][FILENAME_LENGTH];
+        char sortnames[SDSORT_LIMIT][FILENAME_LENGTH];
+      #elif DISABLED(SDSORT_USES_STACK)
+        char sortnames[SDSORT_LIMIT][FILENAME_LENGTH];
+      #endif
+
+      // Folder sorting uses an isDir array when caching items.
+      #if HAS_FOLDER_SORTING && (ENABLED(SDSORT_CACHE_NAMES) || DISABLED(SDSORT_USES_STACK))
+        uint8_t isDir[(SDSORT_LIMIT+7)>>3];
+      #endif
+
+    #endif // SDSORT_USES_RAM
+
+  #endif // SDCARD_SORT_ALPHA
+
   Sd2Card card;
   SdVolume volume;
   SdFile file;
@@ -103,6 +145,10 @@ private:
   uint16_t nrFiles; //counter for the files in the current directory and recycled as position counter for getting the nrFiles'th name in the directory.
   char* diveDirName;
   void lsDive(const char *prepend, SdFile parent, const char * const match=NULL);
+
+  #if ENABLED(SDCARD_SORT_ALPHA)
+    void flush_presort();
+  #endif
 };
 
 extern CardReader card;