From ba42133458d82a6d9f83105b78f8337069b3ac91 Mon Sep 17 00:00:00 2001
From: liamHowatt <30486941+liamHowatt@users.noreply.github.com>
Date: Mon, 25 Mar 2024 02:37:51 -0400
Subject: [PATCH] feat(stdlib): add lv_strncat and refactor strcat uses (#5927)

---
 .../file_explorer/lv_example_file_explorer_1.c     | 13 +------------
 .../file_explorer/lv_example_file_explorer_2.c     | 12 +-----------
 .../file_explorer/lv_example_file_explorer_3.c     | 12 +-----------
 src/stdlib/builtin/lv_string_builtin.c             | 14 ++++++++++++++
 src/stdlib/clib/lv_string_clib.c                   |  5 +++++
 src/stdlib/lv_string.h                             | 12 ++++++++++++
 src/stdlib/rtthread/lv_string_rtthread.c           | 12 ++++++++++++
 7 files changed, 46 insertions(+), 34 deletions(-)

diff --git a/examples/others/file_explorer/lv_example_file_explorer_1.c b/examples/others/file_explorer/lv_example_file_explorer_1.c
index ea92b030f..9145cd361 100644
--- a/examples/others/file_explorer/lv_example_file_explorer_1.c
+++ b/examples/others/file_explorer/lv_example_file_explorer_1.c
@@ -14,18 +14,7 @@ static void file_explorer_event_handler(lv_event_t * e)
     if(code == LV_EVENT_VALUE_CHANGED) {
         const char * cur_path =  lv_file_explorer_get_current_path(obj);
         const char * sel_fn = lv_file_explorer_get_selected_file_name(obj);
-        uint16_t path_len = strlen(cur_path);
-        uint16_t fn_len = strlen(sel_fn);
-
-        if((path_len + fn_len) <= LV_FILE_EXPLORER_PATH_MAX_LEN) {
-            char file_info[LV_FILE_EXPLORER_PATH_MAX_LEN];
-
-            strcpy(file_info, cur_path);
-            strcat(file_info, sel_fn);
-
-            LV_LOG_USER("%s", file_info);
-        }
-        else    LV_LOG_USER("%s%s", cur_path, sel_fn);
+        LV_LOG_USER("%s%s", cur_path, sel_fn);
     }
 }
 
diff --git a/examples/others/file_explorer/lv_example_file_explorer_2.c b/examples/others/file_explorer/lv_example_file_explorer_2.c
index 0bcd01716..082635a6d 100644
--- a/examples/others/file_explorer/lv_example_file_explorer_2.c
+++ b/examples/others/file_explorer/lv_example_file_explorer_2.c
@@ -14,18 +14,8 @@ static void file_explorer_event_handler(lv_event_t * e)
     if(code == LV_EVENT_VALUE_CHANGED) {
         const char * cur_path =  lv_file_explorer_get_current_path(obj);
         const char * sel_fn = lv_file_explorer_get_selected_file_name(obj);
-        uint16_t path_len = strlen(cur_path);
-        uint16_t fn_len = strlen(sel_fn);
 
-        if((path_len + fn_len) <= LV_FILE_EXPLORER_PATH_MAX_LEN) {
-            char file_info[LV_FILE_EXPLORER_PATH_MAX_LEN];
-
-            strcpy(file_info, cur_path);
-            strcat(file_info, sel_fn);
-
-            LV_LOG_USER("%s", file_info);
-        }
-        else    LV_LOG_USER("%s%s", cur_path, sel_fn);
+        LV_LOG_USER("%s%s", cur_path, sel_fn);
     }
 }
 
diff --git a/examples/others/file_explorer/lv_example_file_explorer_3.c b/examples/others/file_explorer/lv_example_file_explorer_3.c
index b475d8a74..7dea32c04 100644
--- a/examples/others/file_explorer/lv_example_file_explorer_3.c
+++ b/examples/others/file_explorer/lv_example_file_explorer_3.c
@@ -50,18 +50,8 @@ static void file_explorer_event_handler(lv_event_t * e)
     if(code == LV_EVENT_VALUE_CHANGED) {
         const char * cur_path =  lv_file_explorer_get_current_path(obj);
         const char * sel_fn = lv_file_explorer_get_selected_file_name(obj);
-        uint16_t path_len = strlen(cur_path);
-        uint16_t fn_len = strlen(sel_fn);
 
-        if((path_len + fn_len) <= LV_FILE_EXPLORER_PATH_MAX_LEN) {
-            char file_info[LV_FILE_EXPLORER_PATH_MAX_LEN];
-
-            strcpy(file_info, cur_path);
-            strcat(file_info, sel_fn);
-
-            LV_LOG_USER("%s", file_info);
-        }
-        else    LV_LOG_USER("%s%s", cur_path, sel_fn);
+        LV_LOG_USER("%s%s", cur_path, sel_fn);
     }
     else if(code == LV_EVENT_READY) {
         lv_obj_t * tb = lv_file_explorer_get_file_table(obj);
diff --git a/src/stdlib/builtin/lv_string_builtin.c b/src/stdlib/builtin/lv_string_builtin.c
index 5cb4f987c..62742a39f 100644
--- a/src/stdlib/builtin/lv_string_builtin.c
+++ b/src/stdlib/builtin/lv_string_builtin.c
@@ -237,6 +237,20 @@ char * lv_strcat(char * dst, const char * src)
     return tmp;
 }
 
+char * lv_strncat(char * dst, const char * src, size_t src_len)
+{
+    char * tmp = dst;
+    while(*dst != '\0') {
+        dst++;
+    }
+    while(src_len != 0 && *src != '\0') {
+        src_len--;
+        *dst++ = *src++;
+    }
+    *dst = '\0';
+    return tmp;
+}
+
 /**********************
  *   STATIC FUNCTIONS
  **********************/
diff --git a/src/stdlib/clib/lv_string_clib.c b/src/stdlib/clib/lv_string_clib.c
index d003b6b7a..bec286e7a 100644
--- a/src/stdlib/clib/lv_string_clib.c
+++ b/src/stdlib/clib/lv_string_clib.c
@@ -96,6 +96,11 @@ char * lv_strcat(char * dst, const char * src)
     return strcat(dst, src);
 }
 
+char * lv_strncat(char * dst, const char * src, size_t src_len)
+{
+    return strncat(dst, src, src_len);
+}
+
 /**********************
  *   STATIC FUNCTIONS
  **********************/
diff --git a/src/stdlib/lv_string.h b/src/stdlib/lv_string.h
index e8d4b45fd..a7dcc7c30 100644
--- a/src/stdlib/lv_string.h
+++ b/src/stdlib/lv_string.h
@@ -124,6 +124,18 @@ char * lv_strdup(const char * src);
  */
 char * lv_strcat(char * dst, const char * src);
 
+/**
+ * @brief Copies up to src_len characters from the string pointed to by src
+ *        to the end of the string pointed to by dst.
+ *        A terminating null character is appended to dst even if no null character
+ *        was encountered in src after src_len characters were copied.
+ * @param dst Pointer to the destination string where the content is to be appended.
+ * @param src Pointer to the source of data to be copied.
+ * @param src_len Maximum number of characters from src to be copied to the end of dst.
+ * @return A pointer to the destination string, which is dst.
+ */
+char * lv_strncat(char * dst, const char * src, size_t src_len);
+
 /**********************
  *      MACROS
  **********************/
diff --git a/src/stdlib/rtthread/lv_string_rtthread.c b/src/stdlib/rtthread/lv_string_rtthread.c
index 14f4b4f74..68ea8d9bc 100644
--- a/src/stdlib/rtthread/lv_string_rtthread.c
+++ b/src/stdlib/rtthread/lv_string_rtthread.c
@@ -90,6 +90,18 @@ char * lv_strcat(char * dst, const char * src)
     return strcat(dst, src);
 }
 
+char * lv_strncat(char * dst, const char * src, size_t src_len)
+{
+    char * tmp = dst;
+    dst += lv_strlen(dst);
+    while(src_len != 0 && *src != '\0') {
+        src_len--;
+        *dst++ = *src++;
+    }
+    *dst = '\0';
+    return tmp;
+}
+
 /**********************
  *   STATIC FUNCTIONS
  **********************/