SD - examples/listfilesEnhanced (#9206)

* add new example for enhanced file listing

* adapt Pin

* adapt due to clanf format check in line 14

* Adapt further clang findings

* additional intention corrections

* last clang format issues corrected

* case-sensitive, eof line break

libraries/SD/examples/listfilesEnhanced/listfilesEnhanced.ino

@@ -0,0 +1,134 @@
+/*
+  Listfiles Enhanced
+
+  This example demonstrates how to list files on an SDcard in the following way:
+   1) collect all directories
+   2) build full path of directories and keep in mind
+   3) then print all files with the help of the directorie pathes
+
+  Wiring:
+   SDcard attached to SPI bus as follows:
+   - MOSI: pin 11
+   - MISO: pin 12
+   - CLK : pin 13
+   - CS  : pin 4
+
+  Created:
+   18. Nov 2024 by Frank Häfele
+
+  This example code is in the public domain.
+
+*/
+#include <SPI.h>
+#include <SD.h>
+#include <vector>
+
+#define SD_CS_PIN 4
+
+
+void dir(String path) {
+  std::vector<String> directories;
+  collectDirectories(path, directories);
+  for (auto directory : directories) {
+    printDirectoryName(directory.c_str(), 1);
+    File fs = SD.open(directory);
+    printFilesInDirectory(fs);
+    Serial.println("\n===============");
+    fs.close();
+  }
+}
+
+void setup() {
+  // Open serial communications and wait for port to open:
+  Serial.begin(115200);
+
+  Serial.print("\n\n==== List Directory ====\n\n");
+  listDirectory();
+
+  Serial.println("done!");
+}
+
+void loop() {
+  // nothing happens after setup finishes.
+}
+
+void listDirectory() {
+  Serial.print("\n\nInitializing SD card...");
+  if (!SD.begin(SD_CS_PIN)) {
+    Serial.println("initialization failed!");
+    return;
+  }
+  Serial.print("initialization successful.\n");
+  Serial.print("List Files:\n");
+  dir("/");
+}
+
+
+void printDirectoryName(const char *name, uint8_t level) {
+  for (uint8_t i = 0; i < level; ++i) {
+    Serial.print("  ");
+  }
+  Serial.println(name);
+}
+
+
+
+// helper function: combine path
+String joinPath(const String &base, const String &name) {
+  if (base.endsWith("/")) {
+    return base + name;
+  }
+  return base + "/" + name;
+}
+
+// recusive function to collect directory names
+void collectDirectories(const String &dirname, std::vector<String> &directories) {
+  File root = SD.open(dirname);
+  if (!root || !root.isDirectory()) {
+    Serial.printf("Error: Cannot open %s\n", dirname.c_str());
+    return;
+  }
+  directories.push_back(dirname);
+
+  File file = root.openNextFile();
+  while (file) {
+    if (file.isDirectory()) {
+      String fullPath = joinPath(dirname, file.name());
+      collectDirectories(fullPath, directories);
+    }
+    file = root.openNextFile();
+  }
+  root.close();
+}
+
+// print filenames
+void printFileName(File file) {
+  Serial.print("\t");
+  Serial.printf("%30s", file.name());
+  // files have sizes, directories do not
+  Serial.print(" - ");
+  Serial.print(file.size(), DEC);
+  time_t cr = file.getCreationTime();
+  time_t lw = file.getLastWrite();
+  struct tm *tmstruct = localtime(&cr);
+  Serial.printf("\tCREATION: %d-%02d-%02d %02d:%02d:%02d", (tmstruct->tm_year) + 1900, (tmstruct->tm_mon) + 1, tmstruct->tm_mday, tmstruct->tm_hour, tmstruct->tm_min, tmstruct->tm_sec);
+  tmstruct = localtime(&lw);
+  Serial.printf("\tLAST WRITE: %d-%02d-%02d %02d:%02d:%02d\n", (tmstruct->tm_year) + 1900, (tmstruct->tm_mon) + 1, tmstruct->tm_mday, tmstruct->tm_hour, tmstruct->tm_min, tmstruct->tm_sec);
+}
+
+
+// print files in directories
+void printFilesInDirectory(File dir) {
+  while (true) {
+    auto file = dir.openNextFile();
+    if (!file) {
+      // no more files
+      break;
+    }
+    if (file.isDirectory()) {
+      continue;
+    } else {
+      printFileName(file);
+    }
+  }
+}