New feature: SDCARD_SORT_ALPHA

.travis.yml

@@ -298,6 +298,15 @@ script:
   - opt_enable G3D_PANEL SDSUPPORT
   - build_marlin
   #
+  # Add SDCARD_SORT_ALPHA, test G3D_PANEL again
+  #
+  - opt_enable_adv SDCARD_SORT_ALPHA
+  - opt_set_adv SDSORT_GCODE true
+  - opt_set_adv SDSORT_USES_RAM true
+  - opt_set_adv SDSORT_USES_STACK true
+  - opt_set_adv SDSORT_CACHE_NAMES true
+  - build_marlin
+  #
   # REPRAP_DISCOUNT_FULL_GRAPHIC_SMART_CONTROLLER
   #
   - restore_configs

Marlin/Conditionals_post.h

@@ -722,4 +722,8 @@
     #define DELTA_ENDSTOP_ADJ { 0 }
   #endif
 
+  #if ENABLED(SDCARD_SORT_ALPHA)
+    #define HAS_FOLDER_SORTING (FOLDER_SORTING || ENABLED(SDSORT_GCODE))
+  #endif
+
 #endif // CONDITIONALS_POST_H

Marlin/Configuration_adv.h

@@ -442,6 +442,40 @@
   // using:
   //#define MENU_ADDAUTOSTART
 
+  /**
+   * Sort SD file listings in alphabetical order.
+   *
+   * With this option enabled, items on SD cards will be sorted
+   * by name for easier navigation.
+   *
+   * By default...
+   *
+   *  - Use the slowest -but safest- method for sorting.
+   *  - Folders are sorted to the top.
+   *  - The sort key is statically allocated.
+   *  - No added G-code (M34) support.
+   *  - 40 item sorting limit. (Items after the first 40 are unsorted.)
+   *
+   * SD sorting uses static allocation (as set by SDSORT_LIMIT), allowing the
+   * compiler to calculate the worst-case usage and throw an error if the SRAM
+   * limit is exceeded.
+   *
+   *  - SDSORT_USES_RAM provides faster sorting via a static directory buffer.
+   *  - SDSORT_USES_STACK does the same, but uses a local stack-based buffer.
+   *  - SDSORT_CACHE_NAMES will retain the sorted file listing in RAM. (Expensive!)
+   */
+  //#define SDCARD_SORT_ALPHA
+
+  // SD Card Sorting options
+  #if ENABLED(SDCARD_SORT_ALPHA)
+    #define SDSORT_LIMIT       40     // Maximum number of sorted items (10-256).
+    #define FOLDER_SORTING     -1     // -1=above  0=none  1=below
+    #define SDSORT_GCODE       false  // Allow turning sorting on/off with LCD and M34 g-code.
+    #define SDSORT_USES_RAM    false  // Pre-allocate a static array for faster pre-sorting.
+    #define SDSORT_USES_STACK  false  // Prefer the stack for pre-sorting to give back some SRAM. (Negated by next 2 options.)
+    #define SDSORT_CACHE_NAMES false  // Keep sorted items in RAM longer for speedy performance. Most expensive option.
+  #endif
+
   // Show a progress bar on HD44780 LCDs for SD printing
   //#define LCD_PROGRESS_BAR
 

Marlin/Marlin_main.cpp

@@ -91,6 +91,7 @@
  *        Use P to run other files as sub-programs: "M32 P !filename#"
  *        The '#' is necessary when calling from within sd files, as it stops buffer prereading
  * M33  - Get the longname version of a path. (Requires LONG_FILENAME_HOST_SUPPORT)
+ * M34  - Set SD Card sorting options. (Requires SDCARD_SORT_ALPHA)
  * M42  - Change pin status via gcode: M42 P<pin> S<value>. LED pin assumed if P is omitted.
  * M43  - Monitor pins & report changes - report active pins
  * M48  - Measure Z Probe repeatability: M48 P<points> X<pos> Y<pos> V<level> E<engage> L<legs>. (Requires Z_MIN_PROBE_REPEATABILITY_TEST)
@@ -4843,6 +4844,20 @@ inline void gcode_M31() {
 
   #endif
 
+  #if ENABLED(SDCARD_SORT_ALPHA) && ENABLED(SDSORT_GCODE)
+    /**
+     * M34: Set SD Card Sorting Options
+     */
+    inline void gcode_M34() {
+      if (code_seen('S')) card.setSortOn(code_value_bool());
+      if (code_seen('F')) {
+        int v = code_value_long();
+        card.setSortFolders(v < 0 ? -1 : v > 0 ? 1 : 0);
+      }
+      //if (code_seen('R')) card.setSortReverse(code_value_bool());
+    }
+  #endif // SDCARD_SORT_ALPHA && SDSORT_GCODE
+
   /**
    * M928: Start SD Write
    */
@@ -8289,6 +8304,11 @@ void process_next_command() {
             gcode_M33(); break;
         #endif
 
+        #if ENABLED(SDCARD_SORT_ALPHA) && ENABLED(SDSORT_GCODE)
+          case 34: //M34 - Set SD card sorting options
+            gcode_M34(); break;
+        #endif // SDCARD_SORT_ALPHA && SDSORT_GCODE
+
         case 928: // M928: Start SD write
           gcode_M928(); break;
       #endif //SDSUPPORT

Marlin/SanityCheck.h

@@ -205,6 +205,19 @@
   #endif
 #endif
 
+/**
+ * SD File Sorting
+ */
+#if ENABLED(SDCARD_SORT_ALPHA)
+  #if SDSORT_LIMIT > 256
+    #error "SDSORT_LIMIT must be 256 or smaller."
+  #elif SDSORT_LIMIT < 10
+    #error "SDSORT_LIMIT should be greater than 9 to be useful."
+  #elif DISABLED(SDSORT_USES_RAM) && ENABLED(SDSORT_CACHE_NAMES)
+    #error "SDSORT_CACHE_NAMES requires SDSORT_USES_RAM (which reads the directory into RAM)."
+  #endif
+#endif
+
 /**
  * Delta requirements
  */

Marlin/cardreader.cpp

@@ -30,7 +30,17 @@
 
 #if ENABLED(SDSUPPORT)
 
+#define LONGEST_FILENAME (longFilename[0] ? longFilename : filename)
+
 CardReader::CardReader() {
+  #if ENABLED(SDCARD_SORT_ALPHA)
+    sort_count = 0;
+    #if ENABLED(SDSORT_GCODE)
+      sort_alpha = true;
+      sort_folders = FOLDER_SORTING;
+      //sort_reverse = false;
+    #endif
+  #endif
   sdprinting = cardOK = saving = logging = false;
   filesize = 0;
   sdpos = 0;
@@ -243,6 +253,9 @@ void CardReader::initsd() {
   }
   workDir = root;
   curDir = &root;
+  #if ENABLED(SDCARD_SORT_ALPHA)
+    presort();
+  #endif
   /**
   if (!workDir.openRoot(&volume)) {
     SERIAL_ECHOLNPGM(MSG_SD_WORKDIR_FAIL);
@@ -256,6 +269,9 @@ void CardReader::setroot() {
   }*/
   workDir = root;
   curDir = &workDir;
+  #if ENABLED(SDCARD_SORT_ALPHA)
+    presort();
+  #endif
 }
 
 void CardReader::release() {
@@ -272,7 +288,12 @@ void CardReader::openAndPrintFile(const char *name) {
 }
 
 void CardReader::startFileprint() {
-  if (cardOK) sdprinting = true;
+  if (cardOK) {
+    sdprinting = true;
+    #if ENABLED(SDCARD_SORT_ALPHA)
+      flush_presort();
+    #endif
+  }
 }
 
 void CardReader::stopSDPrint() {
@@ -463,6 +484,9 @@ void CardReader::removeFile(char* name) {
     SERIAL_PROTOCOLPGM("File deleted:");
     SERIAL_PROTOCOLLN(fname);
     sdpos = 0;
+    #if ENABLED(SDCARD_SORT_ALPHA)
+      presort();
+    #endif
   }
   else {
     SERIAL_PROTOCOLPGM("Deletion failed, File: ");
@@ -551,6 +575,20 @@ void CardReader::closefile(bool store_location) {
  * Get the name of a file in the current directory by index
  */
 void CardReader::getfilename(uint16_t nr, const char * const match/*=NULL*/) {
+  #if ENABLED(SDSORT_CACHE_NAMES)
+    if (match != NULL) {
+      while (nr < sort_count) {
+        if (strcasecmp(match, sortshort[nr]) == 0) break;
+        nr++;
+      }
+    }
+    if (nr < sort_count) {
+      strcpy(filename, sortshort[nr]);
+      strcpy(longFilename, sortnames[nr]);
+      filenameIsDir = TEST(isDir[nr>>3], nr & 0x07);
+      return;
+    }
+  #endif // SDSORT_CACHE_NAMES
   curDir = &workDir;
   lsAction = LS_GetFilename;
   nrFiles = nr;
@@ -583,14 +621,186 @@ void CardReader::chdir(const char * relpath) {
     if (workDirDepth < MAX_DIR_DEPTH)
       workDirParents[workDirDepth++] = *parent;
     workDir = newfile;
+    #if ENABLED(SDCARD_SORT_ALPHA)
+      presort();
+    #endif
   }
 }
 
 void CardReader::updir() {
-  if (workDirDepth > 0)
+  if (workDirDepth > 0) {
     workDir = workDirParents[--workDirDepth];
+    #if ENABLED(SDCARD_SORT_ALPHA)
+      presort();
+    #endif
+  }
 }
 
+#if ENABLED(SDCARD_SORT_ALPHA)
+
+  /**
+   * Get the name of a file in the current directory by sort-index
+   */
+  void CardReader::getfilename_sorted(const uint16_t nr) {
+    getfilename(
+      #if ENABLED(SDSORT_GCODE)
+        sort_alpha &&
+      #endif
+      (nr < sort_count) ? sort_order[nr] : nr
+    );
+  }
+
+  /**
+   * Read all the files and produce a sort key
+   *
+   * We can do this in 3 ways...
+   *  - Minimal RAM: Read two filenames at a time sorting along...
+   *  - Some RAM: Buffer the directory just for this sort
+   *  - Most RAM: Buffer the directory and return filenames from RAM
+   */
+  void CardReader::presort() {
+
+    // Sorting may be turned off
+    #if ENABLED(SDSORT_GCODE)
+      if (!sort_alpha) return;
+    #endif
+
+    // Throw away old sort index
+    flush_presort();
+
+    // If there are files, sort up to the limit
+    uint16_t fileCnt = getnrfilenames();
+    if (fileCnt > 0) {
+
+      // Never sort more than the max allowed
+      // If you use folders to organize, 20 may be enough
+      if (fileCnt > SDSORT_LIMIT) fileCnt = SDSORT_LIMIT;
+
+      // Use RAM to store the entire directory during pre-sort.
+      // SDSORT_LIMIT should be set to prevent over-allocation.
+      #if ENABLED(SDSORT_USES_RAM)
+
+        #if ENABLED(SDSORT_USES_STACK)
+          #if DISABLED(SDSORT_CACHE_NAMES)
+            char sortnames[fileCnt][LONG_FILENAME_LENGTH];
+          #endif
+          // Folder sorting needs 1 bit per entry for flags.
+          #if HAS_FOLDER_SORTING
+            uint8_t isDir[(fileCnt + 7) >> 3];
+          #endif
+        #endif
+
+      #else // !SDSORT_USES_RAM
+
+        // By default re-read the names from SD for every compare
+        // retaining only two filenames at a time. This is very
+        // slow but is safest and uses minimal RAM.
+        char name1[LONG_FILENAME_LENGTH + 1];
+
+      #endif
+
+      if (fileCnt > 1) {
+
+        // Init sort order.
+        for (uint16_t i = 0; i < fileCnt; i++) {
+          sort_order[i] = i;
+          // If using RAM then read all filenames now.
+          #if ENABLED(SDSORT_USES_RAM)
+            getfilename(i);
+            strcpy(sortnames[i], LONGEST_FILENAME);
+            #if ENABLED(SDSORT_CACHE_NAMES)
+              strcpy(sortshort[i], filename);
+            #endif
+            // char out[30];
+            // sprintf_P(out, PSTR("---- %i %s %s"), i, filenameIsDir ? "D" : " ", sortnames[i]);
+            // SERIAL_ECHOLN(out);
+            #if HAS_FOLDER_SORTING
+              const uint16_t bit = i & 0x07, ind = i >> 3;
+              if (bit == 0) isDir[ind] = 0x00;
+              if (filenameIsDir) isDir[ind] |= _BV(bit);
+            #endif
+          #endif
+        }
+
+        // Bubble Sort
+        for (uint16_t i = fileCnt; --i;) {
+          bool didSwap = false;
+          for (uint16_t j = 0; j < i; ++j) {
+            const uint16_t o1 = sort_order[j], o2 = sort_order[j + 1];
+
+            // Compare names from the array or just the two buffered names
+            #if ENABLED(SDSORT_USES_RAM)
+              #define _SORT_CMP_NODIR() (strcasecmp(sortnames[o1], sortnames[o2]) > 0)
+            #else
+              #define _SORT_CMP_NODIR() (strcasecmp(name1, name2) > 0)
+            #endif
+
+            #if HAS_FOLDER_SORTING
+              #if ENABLED(SDSORT_USES_RAM)
+                // Folder sorting needs an index and bit to test for folder-ness.
+                const uint8_t ind1 = o1 >> 3, bit1 = o1 & 0x07,
+                              ind2 = o2 >> 3, bit2 = o2 & 0x07;
+                #define _SORT_CMP_DIR(fs) \
+                  (((isDir[ind1] & _BV(bit1)) != 0) == ((isDir[ind2] & _BV(bit2)) != 0) \
+                    ? _SORT_CMP_NODIR() \
+                    : (isDir[fs > 0 ? ind1 : ind2] & (fs > 0 ? _BV(bit1) : _BV(bit2))) != 0)
+              #else
+                #define _SORT_CMP_DIR(fs) ((dir1 == filenameIsDir) ? _SORT_CMP_NODIR() : (fs > 0 ? dir1 : !dir1))
+              #endif
+            #endif
+
+            // The most economical method reads names as-needed
+            // throughout the loop. Slow if there are many.
+            #if DISABLED(SDSORT_USES_RAM)
+              getfilename(o1);
+              strcpy(name1, LONGEST_FILENAME); // save (or getfilename below will trounce it)
+              #if HAS_FOLDER_SORTING
+                bool dir1 = filenameIsDir;
+              #endif
+              getfilename(o2);
+              char *name2 = LONGEST_FILENAME; // use the string in-place
+            #endif // !SDSORT_USES_RAM
+
+            // Sort the current pair according to settings.
+            if (
+              #if HAS_FOLDER_SORTING
+                #if ENABLED(SDSORT_GCODE)
+                  sort_folders ? _SORT_CMP_DIR(sort_folders) : _SORT_CMP_NODIR()
+                #else
+                  _SORT_CMP_DIR(FOLDER_SORTING)
+                #endif
+              #else
+                _SORT_CMP_NODIR()
+              #endif
+            ) {
+              sort_order[j] = o2;
+              sort_order[j + 1] = o1;
+              didSwap = true;
+            }
+          }
+          if (!didSwap) break;
+        }
+      }
+      else {
+        sort_order[0] = 0;
+        #if ENABLED(SDSORT_USES_RAM) && ENABLED(SDSORT_CACHE_NAMES)
+          getfilename(0);
+          strcpy(sortnames[0], LONGEST_FILENAME);
+          strcpy(sortshort[0], filename);
+          isDir[0] = filenameIsDir ? 0x01 : 0x00;
+        #endif
+      }
+
+      sort_count = fileCnt;
+    }
+  }
+
+  void CardReader::flush_presort() {
+    sort_count = 0;
+  }
+
+#endif // SDCARD_SORT_ALPHA
+
 void CardReader::printingHasFinished() {
   stepper.synchronize();
   file.close();
@@ -607,6 +817,9 @@ void CardReader::printingHasFinished() {
     print_job_timer.stop();
     if (print_job_timer.duration() > 60)
       enqueue_and_echo_commands_P(PSTR("M31"));
+    #if ENABLED(SDCARD_SORT_ALPHA)
+      presort();
+    #endif
   }
 }
 

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;

Marlin/example_configurations/Cartesio/Configuration_adv.h

@@ -442,6 +442,40 @@
   // using:
   //#define MENU_ADDAUTOSTART
 
+  /**
+   * Sort SD file listings in alphabetical order.
+   *
+   * With this option enabled, items on SD cards will be sorted
+   * by name for easier navigation.
+   *
+   * By default...
+   *
+   *  - Use the slowest -but safest- method for sorting.
+   *  - Folders are sorted to the top.
+   *  - The sort key is statically allocated.
+   *  - No added G-code (M34) support.
+   *  - 40 item sorting limit. (Items after the first 40 are unsorted.)
+   *
+   * SD sorting uses static allocation (as set by SDSORT_LIMIT), allowing the
+   * compiler to calculate the worst-case usage and throw an error if the SRAM
+   * limit is exceeded.
+   *
+   *  - SDSORT_USES_RAM provides faster sorting via a static directory buffer.
+   *  - SDSORT_USES_STACK does the same, but uses a local stack-based buffer.
+   *  - SDSORT_CACHE_NAMES will retain the sorted file listing in RAM. (Expensive!)
+   */
+  //#define SDCARD_SORT_ALPHA
+
+  // SD Card Sorting options
+  #if ENABLED(SDCARD_SORT_ALPHA)
+    #define SDSORT_LIMIT       40     // Maximum number of sorted items (10-256).
+    #define FOLDER_SORTING     -1     // -1=above  0=none  1=below
+    #define SDSORT_GCODE       false  // Allow turning sorting on/off with LCD and M34 g-code.
+    #define SDSORT_USES_RAM    false  // Pre-allocate a static array for faster pre-sorting.
+    #define SDSORT_USES_STACK  false  // Prefer the stack for pre-sorting to give back some SRAM. (Negated by next 2 options.)
+    #define SDSORT_CACHE_NAMES false  // Keep sorted items in RAM longer for speedy performance. Most expensive option.
+  #endif
+
   // Show a progress bar on HD44780 LCDs for SD printing
   //#define LCD_PROGRESS_BAR
 

Marlin/example_configurations/Felix/Configuration_adv.h

@@ -442,6 +442,40 @@
   // using:
   //#define MENU_ADDAUTOSTART
 
+  /**
+   * Sort SD file listings in alphabetical order.
+   *
+   * With this option enabled, items on SD cards will be sorted
+   * by name for easier navigation.
+   *
+   * By default...
+   *
+   *  - Use the slowest -but safest- method for sorting.
+   *  - Folders are sorted to the top.
+   *  - The sort key is statically allocated.
+   *  - No added G-code (M34) support.
+   *  - 40 item sorting limit. (Items after the first 40 are unsorted.)
+   *
+   * SD sorting uses static allocation (as set by SDSORT_LIMIT), allowing the
+   * compiler to calculate the worst-case usage and throw an error if the SRAM
+   * limit is exceeded.
+   *
+   *  - SDSORT_USES_RAM provides faster sorting via a static directory buffer.
+   *  - SDSORT_USES_STACK does the same, but uses a local stack-based buffer.
+   *  - SDSORT_CACHE_NAMES will retain the sorted file listing in RAM. (Expensive!)
+   */
+  //#define SDCARD_SORT_ALPHA
+
+  // SD Card Sorting options
+  #if ENABLED(SDCARD_SORT_ALPHA)
+    #define SDSORT_LIMIT       40     // Maximum number of sorted items (10-256).
+    #define FOLDER_SORTING     -1     // -1=above  0=none  1=below
+    #define SDSORT_GCODE       false  // Allow turning sorting on/off with LCD and M34 g-code.
+    #define SDSORT_USES_RAM    false  // Pre-allocate a static array for faster pre-sorting.
+    #define SDSORT_USES_STACK  false  // Prefer the stack for pre-sorting to give back some SRAM. (Negated by next 2 options.)
+    #define SDSORT_CACHE_NAMES false  // Keep sorted items in RAM longer for speedy performance. Most expensive option.
+  #endif
+
   // Show a progress bar on HD44780 LCDs for SD printing
   //#define LCD_PROGRESS_BAR
 

Marlin/example_configurations/Hephestos/Configuration_adv.h

@@ -442,6 +442,40 @@
   // using:
   //#define MENU_ADDAUTOSTART
 
+  /**
+   * Sort SD file listings in alphabetical order.
+   *
+   * With this option enabled, items on SD cards will be sorted
+   * by name for easier navigation.
+   *
+   * By default...
+   *
+   *  - Use the slowest -but safest- method for sorting.
+   *  - Folders are sorted to the top.
+   *  - The sort key is statically allocated.
+   *  - No added G-code (M34) support.
+   *  - 40 item sorting limit. (Items after the first 40 are unsorted.)
+   *
+   * SD sorting uses static allocation (as set by SDSORT_LIMIT), allowing the
+   * compiler to calculate the worst-case usage and throw an error if the SRAM
+   * limit is exceeded.
+   *
+   *  - SDSORT_USES_RAM provides faster sorting via a static directory buffer.
+   *  - SDSORT_USES_STACK does the same, but uses a local stack-based buffer.
+   *  - SDSORT_CACHE_NAMES will retain the sorted file listing in RAM. (Expensive!)
+   */
+  //#define SDCARD_SORT_ALPHA
+
+  // SD Card Sorting options
+  #if ENABLED(SDCARD_SORT_ALPHA)
+    #define SDSORT_LIMIT       40     // Maximum number of sorted items (10-256).
+    #define FOLDER_SORTING     -1     // -1=above  0=none  1=below
+    #define SDSORT_GCODE       false  // Allow turning sorting on/off with LCD and M34 g-code.
+    #define SDSORT_USES_RAM    false  // Pre-allocate a static array for faster pre-sorting.
+    #define SDSORT_USES_STACK  false  // Prefer the stack for pre-sorting to give back some SRAM. (Negated by next 2 options.)
+    #define SDSORT_CACHE_NAMES false  // Keep sorted items in RAM longer for speedy performance. Most expensive option.
+  #endif
+
   // Show a progress bar on HD44780 LCDs for SD printing
   //#define LCD_PROGRESS_BAR
 

Marlin/example_configurations/Hephestos_2/Configuration_adv.h

@@ -442,6 +442,40 @@
   // using:
   //#define MENU_ADDAUTOSTART
 
+  /**
+   * Sort SD file listings in alphabetical order.
+   *
+   * With this option enabled, items on SD cards will be sorted
+   * by name for easier navigation.
+   *
+   * By default...
+   *
+   *  - Use the slowest -but safest- method for sorting.
+   *  - Folders are sorted to the top.
+   *  - The sort key is statically allocated.
+   *  - No added G-code (M34) support.
+   *  - 40 item sorting limit. (Items after the first 40 are unsorted.)
+   *
+   * SD sorting uses static allocation (as set by SDSORT_LIMIT), allowing the
+   * compiler to calculate the worst-case usage and throw an error if the SRAM
+   * limit is exceeded.
+   *
+   *  - SDSORT_USES_RAM provides faster sorting via a static directory buffer.
+   *  - SDSORT_USES_STACK does the same, but uses a local stack-based buffer.
+   *  - SDSORT_CACHE_NAMES will retain the sorted file listing in RAM. (Expensive!)
+   */
+  //#define SDCARD_SORT_ALPHA
+
+  // SD Card Sorting options
+  #if ENABLED(SDCARD_SORT_ALPHA)
+    #define SDSORT_LIMIT       40     // Maximum number of sorted items (10-256).
+    #define FOLDER_SORTING     -1     // -1=above  0=none  1=below
+    #define SDSORT_GCODE       false  // Allow turning sorting on/off with LCD and M34 g-code.
+    #define SDSORT_USES_RAM    false  // Pre-allocate a static array for faster pre-sorting.
+    #define SDSORT_USES_STACK  false  // Prefer the stack for pre-sorting to give back some SRAM. (Negated by next 2 options.)
+    #define SDSORT_CACHE_NAMES false  // Keep sorted items in RAM longer for speedy performance. Most expensive option.
+  #endif
+
   // Show a progress bar on HD44780 LCDs for SD printing
   //#define LCD_PROGRESS_BAR
 

Marlin/example_configurations/K8200/Configuration_adv.h

@@ -455,6 +455,40 @@
   // using:
   #define MENU_ADDAUTOSTART
 
+  /**
+   * Sort SD file listings in alphabetical order.
+   *
+   * With this option enabled, items on SD cards will be sorted
+   * by name for easier navigation.
+   *
+   * By default...
+   *
+   *  - Use the slowest -but safest- method for sorting.
+   *  - Folders are sorted to the top.
+   *  - The sort key is statically allocated.
+   *  - No added G-code (M34) support.
+   *  - 40 item sorting limit. (Items after the first 40 are unsorted.)
+   *
+   * SD sorting uses static allocation (as set by SDSORT_LIMIT), allowing the
+   * compiler to calculate the worst-case usage and throw an error if the SRAM
+   * limit is exceeded.
+   *
+   *  - SDSORT_USES_RAM provides faster sorting via a static directory buffer.
+   *  - SDSORT_USES_STACK does the same, but uses a local stack-based buffer.
+   *  - SDSORT_CACHE_NAMES will retain the sorted file listing in RAM. (Expensive!)
+   */
+  //#define SDCARD_SORT_ALPHA
+
+  // SD Card Sorting options
+  #if ENABLED(SDCARD_SORT_ALPHA)
+    #define SDSORT_LIMIT       40     // Maximum number of sorted items (10-256).
+    #define FOLDER_SORTING     -1     // -1=above  0=none  1=below
+    #define SDSORT_GCODE       false  // Allow turning sorting on/off with LCD and M34 g-code.
+    #define SDSORT_USES_RAM    false  // Pre-allocate a static array for faster pre-sorting.
+    #define SDSORT_USES_STACK  false  // Prefer the stack for pre-sorting to give back some SRAM. (Negated by next 2 options.)
+    #define SDSORT_CACHE_NAMES false  // Keep sorted items in RAM longer for speedy performance. Most expensive option.
+  #endif
+
   // Show a progress bar on HD44780 LCDs for SD printing
   #define LCD_PROGRESS_BAR
 

Marlin/example_configurations/K8400/Configuration_adv.h

@@ -442,6 +442,40 @@
   // using:
   //#define MENU_ADDAUTOSTART
 
+  /**
+   * Sort SD file listings in alphabetical order.
+   *
+   * With this option enabled, items on SD cards will be sorted
+   * by name for easier navigation.
+   *
+   * By default...
+   *
+   *  - Use the slowest -but safest- method for sorting.
+   *  - Folders are sorted to the top.
+   *  - The sort key is statically allocated.
+   *  - No added G-code (M34) support.
+   *  - 40 item sorting limit. (Items after the first 40 are unsorted.)
+   *
+   * SD sorting uses static allocation (as set by SDSORT_LIMIT), allowing the
+   * compiler to calculate the worst-case usage and throw an error if the SRAM
+   * limit is exceeded.
+   *
+   *  - SDSORT_USES_RAM provides faster sorting via a static directory buffer.
+   *  - SDSORT_USES_STACK does the same, but uses a local stack-based buffer.
+   *  - SDSORT_CACHE_NAMES will retain the sorted file listing in RAM. (Expensive!)
+   */
+  //#define SDCARD_SORT_ALPHA
+
+  // SD Card Sorting options
+  #if ENABLED(SDCARD_SORT_ALPHA)
+    #define SDSORT_LIMIT       40     // Maximum number of sorted items (10-256).
+    #define FOLDER_SORTING     -1     // -1=above  0=none  1=below
+    #define SDSORT_GCODE       false  // Allow turning sorting on/off with LCD and M34 g-code.
+    #define SDSORT_USES_RAM    false  // Pre-allocate a static array for faster pre-sorting.
+    #define SDSORT_USES_STACK  false  // Prefer the stack for pre-sorting to give back some SRAM. (Negated by next 2 options.)
+    #define SDSORT_CACHE_NAMES false  // Keep sorted items in RAM longer for speedy performance. Most expensive option.
+  #endif
+
   // Show a progress bar on HD44780 LCDs for SD printing
   //#define LCD_PROGRESS_BAR
 

Marlin/example_configurations/RigidBot/Configuration_adv.h

@@ -442,6 +442,40 @@
   // using:
   //#define MENU_ADDAUTOSTART
 
+  /**
+   * Sort SD file listings in alphabetical order.
+   *
+   * With this option enabled, items on SD cards will be sorted
+   * by name for easier navigation.
+   *
+   * By default...
+   *
+   *  - Use the slowest -but safest- method for sorting.
+   *  - Folders are sorted to the top.
+   *  - The sort key is statically allocated.
+   *  - No added G-code (M34) support.
+   *  - 40 item sorting limit. (Items after the first 40 are unsorted.)
+   *
+   * SD sorting uses static allocation (as set by SDSORT_LIMIT), allowing the
+   * compiler to calculate the worst-case usage and throw an error if the SRAM
+   * limit is exceeded.
+   *
+   *  - SDSORT_USES_RAM provides faster sorting via a static directory buffer.
+   *  - SDSORT_USES_STACK does the same, but uses a local stack-based buffer.
+   *  - SDSORT_CACHE_NAMES will retain the sorted file listing in RAM. (Expensive!)
+   */
+  //#define SDCARD_SORT_ALPHA
+
+  // SD Card Sorting options
+  #if ENABLED(SDCARD_SORT_ALPHA)
+    #define SDSORT_LIMIT       40     // Maximum number of sorted items (10-256).
+    #define FOLDER_SORTING     -1     // -1=above  0=none  1=below
+    #define SDSORT_GCODE       false  // Allow turning sorting on/off with LCD and M34 g-code.
+    #define SDSORT_USES_RAM    false  // Pre-allocate a static array for faster pre-sorting.
+    #define SDSORT_USES_STACK  false  // Prefer the stack for pre-sorting to give back some SRAM. (Negated by next 2 options.)
+    #define SDSORT_CACHE_NAMES false  // Keep sorted items in RAM longer for speedy performance. Most expensive option.
+  #endif
+
   // Show a progress bar on HD44780 LCDs for SD printing
   //#define LCD_PROGRESS_BAR
 

Marlin/example_configurations/SCARA/Configuration_adv.h

@@ -442,6 +442,40 @@
   // using:
   //#define MENU_ADDAUTOSTART
 
+  /**
+   * Sort SD file listings in alphabetical order.
+   *
+   * With this option enabled, items on SD cards will be sorted
+   * by name for easier navigation.
+   *
+   * By default...
+   *
+   *  - Use the slowest -but safest- method for sorting.
+   *  - Folders are sorted to the top.
+   *  - The sort key is statically allocated.
+   *  - No added G-code (M34) support.
+   *  - 40 item sorting limit. (Items after the first 40 are unsorted.)
+   *
+   * SD sorting uses static allocation (as set by SDSORT_LIMIT), allowing the
+   * compiler to calculate the worst-case usage and throw an error if the SRAM
+   * limit is exceeded.
+   *
+   *  - SDSORT_USES_RAM provides faster sorting via a static directory buffer.
+   *  - SDSORT_USES_STACK does the same, but uses a local stack-based buffer.
+   *  - SDSORT_CACHE_NAMES will retain the sorted file listing in RAM. (Expensive!)
+   */
+  //#define SDCARD_SORT_ALPHA
+
+  // SD Card Sorting options
+  #if ENABLED(SDCARD_SORT_ALPHA)
+    #define SDSORT_LIMIT       40     // Maximum number of sorted items (10-256).
+    #define FOLDER_SORTING     -1     // -1=above  0=none  1=below
+    #define SDSORT_GCODE       false  // Allow turning sorting on/off with LCD and M34 g-code.
+    #define SDSORT_USES_RAM    false  // Pre-allocate a static array for faster pre-sorting.
+    #define SDSORT_USES_STACK  false  // Prefer the stack for pre-sorting to give back some SRAM. (Negated by next 2 options.)
+    #define SDSORT_CACHE_NAMES false  // Keep sorted items in RAM longer for speedy performance. Most expensive option.
+  #endif
+
   // Show a progress bar on HD44780 LCDs for SD printing
   //#define LCD_PROGRESS_BAR
 

Marlin/example_configurations/TAZ4/Configuration_adv.h

@@ -450,6 +450,40 @@
   // using:
   //#define MENU_ADDAUTOSTART
 
+  /**
+   * Sort SD file listings in alphabetical order.
+   *
+   * With this option enabled, items on SD cards will be sorted
+   * by name for easier navigation.
+   *
+   * By default...
+   *
+   *  - Use the slowest -but safest- method for sorting.
+   *  - Folders are sorted to the top.
+   *  - The sort key is statically allocated.
+   *  - No added G-code (M34) support.
+   *  - 40 item sorting limit. (Items after the first 40 are unsorted.)
+   *
+   * SD sorting uses static allocation (as set by SDSORT_LIMIT), allowing the
+   * compiler to calculate the worst-case usage and throw an error if the SRAM
+   * limit is exceeded.
+   *
+   *  - SDSORT_USES_RAM provides faster sorting via a static directory buffer.
+   *  - SDSORT_USES_STACK does the same, but uses a local stack-based buffer.
+   *  - SDSORT_CACHE_NAMES will retain the sorted file listing in RAM. (Expensive!)
+   */
+  //#define SDCARD_SORT_ALPHA
+
+  // SD Card Sorting options
+  #if ENABLED(SDCARD_SORT_ALPHA)
+    #define SDSORT_LIMIT       40     // Maximum number of sorted items (10-256).
+    #define FOLDER_SORTING     -1     // -1=above  0=none  1=below
+    #define SDSORT_GCODE       false  // Allow turning sorting on/off with LCD and M34 g-code.
+    #define SDSORT_USES_RAM    false  // Pre-allocate a static array for faster pre-sorting.
+    #define SDSORT_USES_STACK  false  // Prefer the stack for pre-sorting to give back some SRAM. (Negated by next 2 options.)
+    #define SDSORT_CACHE_NAMES false  // Keep sorted items in RAM longer for speedy performance. Most expensive option.
+  #endif
+
   // Show a progress bar on HD44780 LCDs for SD printing
   //#define LCD_PROGRESS_BAR
 

Marlin/example_configurations/WITBOX/Configuration_adv.h

@@ -442,6 +442,40 @@
   // using:
   //#define MENU_ADDAUTOSTART
 
+  /**
+   * Sort SD file listings in alphabetical order.
+   *
+   * With this option enabled, items on SD cards will be sorted
+   * by name for easier navigation.
+   *
+   * By default...
+   *
+   *  - Use the slowest -but safest- method for sorting.
+   *  - Folders are sorted to the top.
+   *  - The sort key is statically allocated.
+   *  - No added G-code (M34) support.
+   *  - 40 item sorting limit. (Items after the first 40 are unsorted.)
+   *
+   * SD sorting uses static allocation (as set by SDSORT_LIMIT), allowing the
+   * compiler to calculate the worst-case usage and throw an error if the SRAM
+   * limit is exceeded.
+   *
+   *  - SDSORT_USES_RAM provides faster sorting via a static directory buffer.
+   *  - SDSORT_USES_STACK does the same, but uses a local stack-based buffer.
+   *  - SDSORT_CACHE_NAMES will retain the sorted file listing in RAM. (Expensive!)
+   */
+  //#define SDCARD_SORT_ALPHA
+
+  // SD Card Sorting options
+  #if ENABLED(SDCARD_SORT_ALPHA)
+    #define SDSORT_LIMIT       40     // Maximum number of sorted items (10-256).
+    #define FOLDER_SORTING     -1     // -1=above  0=none  1=below
+    #define SDSORT_GCODE       false  // Allow turning sorting on/off with LCD and M34 g-code.
+    #define SDSORT_USES_RAM    false  // Pre-allocate a static array for faster pre-sorting.
+    #define SDSORT_USES_STACK  false  // Prefer the stack for pre-sorting to give back some SRAM. (Negated by next 2 options.)
+    #define SDSORT_CACHE_NAMES false  // Keep sorted items in RAM longer for speedy performance. Most expensive option.
+  #endif
+
   // Show a progress bar on HD44780 LCDs for SD printing
   //#define LCD_PROGRESS_BAR
 

Marlin/example_configurations/delta/generic/Configuration_adv.h

@@ -444,6 +444,40 @@
   // using:
   //#define MENU_ADDAUTOSTART
 
+  /**
+   * Sort SD file listings in alphabetical order.
+   *
+   * With this option enabled, items on SD cards will be sorted
+   * by name for easier navigation.
+   *
+   * By default...
+   *
+   *  - Use the slowest -but safest- method for sorting.
+   *  - Folders are sorted to the top.
+   *  - The sort key is statically allocated.
+   *  - No added G-code (M34) support.
+   *  - 40 item sorting limit. (Items after the first 40 are unsorted.)
+   *
+   * SD sorting uses static allocation (as set by SDSORT_LIMIT), allowing the
+   * compiler to calculate the worst-case usage and throw an error if the SRAM
+   * limit is exceeded.
+   *
+   *  - SDSORT_USES_RAM provides faster sorting via a static directory buffer.
+   *  - SDSORT_USES_STACK does the same, but uses a local stack-based buffer.
+   *  - SDSORT_CACHE_NAMES will retain the sorted file listing in RAM. (Expensive!)
+   */
+  //#define SDCARD_SORT_ALPHA
+
+  // SD Card Sorting options
+  #if ENABLED(SDCARD_SORT_ALPHA)
+    #define SDSORT_LIMIT       40     // Maximum number of sorted items (10-256).
+    #define FOLDER_SORTING     -1     // -1=above  0=none  1=below
+    #define SDSORT_GCODE       false  // Allow turning sorting on/off with LCD and M34 g-code.
+    #define SDSORT_USES_RAM    false  // Pre-allocate a static array for faster pre-sorting.
+    #define SDSORT_USES_STACK  false  // Prefer the stack for pre-sorting to give back some SRAM. (Negated by next 2 options.)
+    #define SDSORT_CACHE_NAMES false  // Keep sorted items in RAM longer for speedy performance. Most expensive option.
+  #endif
+
   // Show a progress bar on HD44780 LCDs for SD printing
   //#define LCD_PROGRESS_BAR
 

Marlin/example_configurations/delta/kossel_mini/Configuration_adv.h

@@ -444,6 +444,40 @@
   // using:
   //#define MENU_ADDAUTOSTART
 
+  /**
+   * Sort SD file listings in alphabetical order.
+   *
+   * With this option enabled, items on SD cards will be sorted
+   * by name for easier navigation.
+   *
+   * By default...
+   *
+   *  - Use the slowest -but safest- method for sorting.
+   *  - Folders are sorted to the top.
+   *  - The sort key is statically allocated.
+   *  - No added G-code (M34) support.
+   *  - 40 item sorting limit. (Items after the first 40 are unsorted.)
+   *
+   * SD sorting uses static allocation (as set by SDSORT_LIMIT), allowing the
+   * compiler to calculate the worst-case usage and throw an error if the SRAM
+   * limit is exceeded.
+   *
+   *  - SDSORT_USES_RAM provides faster sorting via a static directory buffer.
+   *  - SDSORT_USES_STACK does the same, but uses a local stack-based buffer.
+   *  - SDSORT_CACHE_NAMES will retain the sorted file listing in RAM. (Expensive!)
+   */
+  //#define SDCARD_SORT_ALPHA
+
+  // SD Card Sorting options
+  #if ENABLED(SDCARD_SORT_ALPHA)
+    #define SDSORT_LIMIT       40     // Maximum number of sorted items (10-256).
+    #define FOLDER_SORTING     -1     // -1=above  0=none  1=below
+    #define SDSORT_GCODE       false  // Allow turning sorting on/off with LCD and M34 g-code.
+    #define SDSORT_USES_RAM    false  // Pre-allocate a static array for faster pre-sorting.
+    #define SDSORT_USES_STACK  false  // Prefer the stack for pre-sorting to give back some SRAM. (Negated by next 2 options.)
+    #define SDSORT_CACHE_NAMES false  // Keep sorted items in RAM longer for speedy performance. Most expensive option.
+  #endif
+
   // Show a progress bar on HD44780 LCDs for SD printing
   //#define LCD_PROGRESS_BAR
 

Marlin/example_configurations/delta/kossel_pro/Configuration_adv.h

@@ -449,6 +449,40 @@
   // using:
   //#define MENU_ADDAUTOSTART
 
+  /**
+   * Sort SD file listings in alphabetical order.
+   *
+   * With this option enabled, items on SD cards will be sorted
+   * by name for easier navigation.
+   *
+   * By default...
+   *
+   *  - Use the slowest -but safest- method for sorting.
+   *  - Folders are sorted to the top.
+   *  - The sort key is statically allocated.
+   *  - No added G-code (M34) support.
+   *  - 40 item sorting limit. (Items after the first 40 are unsorted.)
+   *
+   * SD sorting uses static allocation (as set by SDSORT_LIMIT), allowing the
+   * compiler to calculate the worst-case usage and throw an error if the SRAM
+   * limit is exceeded.
+   *
+   *  - SDSORT_USES_RAM provides faster sorting via a static directory buffer.
+   *  - SDSORT_USES_STACK does the same, but uses a local stack-based buffer.
+   *  - SDSORT_CACHE_NAMES will retain the sorted file listing in RAM. (Expensive!)
+   */
+  //#define SDCARD_SORT_ALPHA
+
+  // SD Card Sorting options
+  #if ENABLED(SDCARD_SORT_ALPHA)
+    #define SDSORT_LIMIT       40     // Maximum number of sorted items (10-256).
+    #define FOLDER_SORTING     -1     // -1=above  0=none  1=below
+    #define SDSORT_GCODE       false  // Allow turning sorting on/off with LCD and M34 g-code.
+    #define SDSORT_USES_RAM    false  // Pre-allocate a static array for faster pre-sorting.
+    #define SDSORT_USES_STACK  false  // Prefer the stack for pre-sorting to give back some SRAM. (Negated by next 2 options.)
+    #define SDSORT_CACHE_NAMES false  // Keep sorted items in RAM longer for speedy performance. Most expensive option.
+  #endif
+
   // Show a progress bar on HD44780 LCDs for SD printing
   //#define LCD_PROGRESS_BAR
 

Marlin/example_configurations/delta/kossel_xl/Configuration_adv.h

@@ -444,6 +444,40 @@
   // using:
   //#define MENU_ADDAUTOSTART
 
+  /**
+   * Sort SD file listings in alphabetical order.
+   *
+   * With this option enabled, items on SD cards will be sorted
+   * by name for easier navigation.
+   *
+   * By default...
+   *
+   *  - Use the slowest -but safest- method for sorting.
+   *  - Folders are sorted to the top.
+   *  - The sort key is statically allocated.
+   *  - No added G-code (M34) support.
+   *  - 40 item sorting limit. (Items after the first 40 are unsorted.)
+   *
+   * SD sorting uses static allocation (as set by SDSORT_LIMIT), allowing the
+   * compiler to calculate the worst-case usage and throw an error if the SRAM
+   * limit is exceeded.
+   *
+   *  - SDSORT_USES_RAM provides faster sorting via a static directory buffer.
+   *  - SDSORT_USES_STACK does the same, but uses a local stack-based buffer.
+   *  - SDSORT_CACHE_NAMES will retain the sorted file listing in RAM. (Expensive!)
+   */
+  //#define SDCARD_SORT_ALPHA
+
+  // SD Card Sorting options
+  #if ENABLED(SDCARD_SORT_ALPHA)
+    #define SDSORT_LIMIT       40     // Maximum number of sorted items (10-256).
+    #define FOLDER_SORTING     -1     // -1=above  0=none  1=below
+    #define SDSORT_GCODE       false  // Allow turning sorting on/off with LCD and M34 g-code.
+    #define SDSORT_USES_RAM    false  // Pre-allocate a static array for faster pre-sorting.
+    #define SDSORT_USES_STACK  false  // Prefer the stack for pre-sorting to give back some SRAM. (Negated by next 2 options.)
+    #define SDSORT_CACHE_NAMES false  // Keep sorted items in RAM longer for speedy performance. Most expensive option.
+  #endif
+
   // Show a progress bar on HD44780 LCDs for SD printing
   //#define LCD_PROGRESS_BAR
 

Marlin/example_configurations/makibox/Configuration_adv.h

@@ -442,6 +442,40 @@
   // using:
   //#define MENU_ADDAUTOSTART
 
+  /**
+   * Sort SD file listings in alphabetical order.
+   *
+   * With this option enabled, items on SD cards will be sorted
+   * by name for easier navigation.
+   *
+   * By default...
+   *
+   *  - Use the slowest -but safest- method for sorting.
+   *  - Folders are sorted to the top.
+   *  - The sort key is statically allocated.
+   *  - No added G-code (M34) support.
+   *  - 40 item sorting limit. (Items after the first 40 are unsorted.)
+   *
+   * SD sorting uses static allocation (as set by SDSORT_LIMIT), allowing the
+   * compiler to calculate the worst-case usage and throw an error if the SRAM
+   * limit is exceeded.
+   *
+   *  - SDSORT_USES_RAM provides faster sorting via a static directory buffer.
+   *  - SDSORT_USES_STACK does the same, but uses a local stack-based buffer.
+   *  - SDSORT_CACHE_NAMES will retain the sorted file listing in RAM. (Expensive!)
+   */
+  //#define SDCARD_SORT_ALPHA
+
+  // SD Card Sorting options
+  #if ENABLED(SDCARD_SORT_ALPHA)
+    #define SDSORT_LIMIT       40     // Maximum number of sorted items (10-256).
+    #define FOLDER_SORTING     -1     // -1=above  0=none  1=below
+    #define SDSORT_GCODE       false  // Allow turning sorting on/off with LCD and M34 g-code.
+    #define SDSORT_USES_RAM    false  // Pre-allocate a static array for faster pre-sorting.
+    #define SDSORT_USES_STACK  false  // Prefer the stack for pre-sorting to give back some SRAM. (Negated by next 2 options.)
+    #define SDSORT_CACHE_NAMES false  // Keep sorted items in RAM longer for speedy performance. Most expensive option.
+  #endif
+
   // Show a progress bar on HD44780 LCDs for SD printing
   //#define LCD_PROGRESS_BAR
 

Marlin/example_configurations/tvrrug/Round2/Configuration_adv.h

@@ -442,6 +442,40 @@
   // using:
   //#define MENU_ADDAUTOSTART
 
+  /**
+   * Sort SD file listings in alphabetical order.
+   *
+   * With this option enabled, items on SD cards will be sorted
+   * by name for easier navigation.
+   *
+   * By default...
+   *
+   *  - Use the slowest -but safest- method for sorting.
+   *  - Folders are sorted to the top.
+   *  - The sort key is statically allocated.
+   *  - No added G-code (M34) support.
+   *  - 40 item sorting limit. (Items after the first 40 are unsorted.)
+   *
+   * SD sorting uses static allocation (as set by SDSORT_LIMIT), allowing the
+   * compiler to calculate the worst-case usage and throw an error if the SRAM
+   * limit is exceeded.
+   *
+   *  - SDSORT_USES_RAM provides faster sorting via a static directory buffer.
+   *  - SDSORT_USES_STACK does the same, but uses a local stack-based buffer.
+   *  - SDSORT_CACHE_NAMES will retain the sorted file listing in RAM. (Expensive!)
+   */
+  //#define SDCARD_SORT_ALPHA
+
+  // SD Card Sorting options
+  #if ENABLED(SDCARD_SORT_ALPHA)
+    #define SDSORT_LIMIT       40     // Maximum number of sorted items (10-256).
+    #define FOLDER_SORTING     -1     // -1=above  0=none  1=below
+    #define SDSORT_GCODE       false  // Allow turning sorting on/off with LCD and M34 g-code.
+    #define SDSORT_USES_RAM    false  // Pre-allocate a static array for faster pre-sorting.
+    #define SDSORT_USES_STACK  false  // Prefer the stack for pre-sorting to give back some SRAM. (Negated by next 2 options.)
+    #define SDSORT_CACHE_NAMES false  // Keep sorted items in RAM longer for speedy performance. Most expensive option.
+  #endif
+
   // Show a progress bar on HD44780 LCDs for SD printing
   //#define LCD_PROGRESS_BAR
 

Marlin/ultralcd.cpp

@@ -2277,12 +2277,17 @@ KeepDrawing:
 
       for (uint16_t i = 0; i < fileCnt; i++) {
         if (_menuLineNr == _thisItemNr) {
-          card.getfilename(
+          #if ENABLED(SDCARD_RATHERRECENTFIRST) && DISABLED(SDCARD_SORT_ALPHA)
-             #if ENABLED(SDCARD_RATHERRECENTFIRST)
+            int nr = fileCnt - 1 - i;
-               fileCnt-1 -
+          #else
-             #endif
+            int nr = i;
-             i
+          #endif
-          );
+
+          #if ENABLED(SDCARD_SORT_ALPHA)
+            card.getfilename_sorted(nr);
+          #else
+            card.getfilename(nr);
+          #endif
 
           if (card.filenameIsDir)
             MENU_ITEM(sddirectory, MSG_CARD_MENU, card.filename, card.longFilename);