From 0cc34bfd6b5f21a8c053af2893d729ad9195ed17 Mon Sep 17 00:00:00 2001
From: Sani7 <sander.speetjens@gmail.com>
Date: Sat, 2 Dec 2023 23:01:06 +0100
Subject: [PATCH] LLFS

add llfs_get_filename_ext
---
 docs/llfs.md            | 24 ++++++++++++++++++++++++
 project/Core/Inc/llfs.h |  7 +++++++
 project/Core/Src/llfs.c |  7 +++++++
 3 files changed, 38 insertions(+)

diff --git a/docs/llfs.md b/docs/llfs.md
index 38f4a7b..1311238 100644
--- a/docs/llfs.md
+++ b/docs/llfs.md
@@ -23,6 +23,7 @@ restricting operations solely to read functions.
      - [Iterator function (not recommended)](#iterator-function-not-recommended)
    - [Reading a file](#reading-a-file)
    - [Getting the number of files](#getting-the-number-of-files)
+    - [Getting a file extension](#getting-a-file-extension)
  - [Using the POSIX file functions](#using-the-posix-file-functions)
  - [Enabling the external loader in STM32CubeIDE](#enabling-the-external-loader-in-stm32cubeide)
 
@@ -144,6 +145,29 @@ void main(void) {
 }
 ```
 
+### Getting a file extension
+```c
+#include "llfs.h"
+void main(void) {
+    llfs_init();
+    
+    // Get a file by name
+    llfs_file_t* file = llfs_file_open("filename with a space.txt");
+    
+    if (file != NULL) {
+        // Print the file name, size and data
+        LOG_INFO(TAG, "File found: %s, size: %d", file->name, file->len);
+        LOG_INFO(TAG, "File data: %s", file->data);
+        
+        // Get the file extension
+        const char* ext = llfs_file_ext(file->name);
+        LOG_INFO(TAG, "File extension: %s", ext);
+    } else {
+        LOG_WARN(TAG, "File not found");
+    }
+}
+```
+
 ## Using the POSIX file functions
 The llfs library also supports the POSIX file functions.
 As the file system is read-only, write functions are not implemented.
diff --git a/project/Core/Inc/llfs.h b/project/Core/Inc/llfs.h
index 780a73b..4707873 100644
--- a/project/Core/Inc/llfs.h
+++ b/project/Core/Inc/llfs.h
@@ -83,4 +83,11 @@ llfs_file_t* llfs_next_file(void** mem, char* filter);
  */
 size_t llfs_file_count(void);
 
+/**
+ * @brief This function returns the extension of a file
+ * @param[in] filename The filename to get the extension from
+ * @return char* The extension of the file
+ */
+char* llfs_get_filename_ext(char* filename);
+
 #endif // LLFS_H
diff --git a/project/Core/Src/llfs.c b/project/Core/Src/llfs.c
index 7866be9..155c9bb 100644
--- a/project/Core/Src/llfs.c
+++ b/project/Core/Src/llfs.c
@@ -141,6 +141,13 @@ size_t llfs_file_count(void) {
     return file_count;
 }
 
+char* llfs_get_filename_ext(char* filename) {
+    char* dot = strrchr(filename, '.');
+    if (dot == NULL || dot == filename)
+        return NULL;
+    return dot + 1;
+}
+
 #ifndef TESTING
 /**
  * @brief Newlib open implementation