last_index_of(pos);

Author: schreibfaul1

src/psram_unique_ptr.hpp

@@ -168,9 +168,7 @@ class ps_ptr {
     }
 
     // 🆕 alloc constructor, e.g. ps_ptr<char>buff(1024)
-    explicit ps_ptr(size_t n) {
-        alloc(n);
-    }
+    explicit ps_ptr(size_t n) { alloc(n); }
     // —————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————
     // 📌📌📌  A L L O C  📌📌📌
 
@@ -1196,12 +1194,16 @@ class ps_ptr {
 
     template <typename U = T>
         requires std::is_same_v<U, char>
-    int last_index_of(char ch) const {
+    int last_index_of(char ch, int start_pos = -1) const {
         if (!mem) return -1;
 
         const char* str = static_cast<const char*>(mem.get());
         int         len = static_cast<int>(std::strlen(str));
-        for (int i = len - 1; i >= 0; --i) {
+
+        // if no start position is specified, start at the end
+        if (start_pos < 0 || start_pos >= len) start_pos = len - 1;
+
+        for (int i = start_pos; i >= 0; --i) {
             if (str[i] == ch) return i;
         }
         return -1;
@@ -1214,12 +1216,20 @@ class ps_ptr {
     // printf("last_i  %i\n", last_i);
     // printf("last_A  %i\n", last_A);
 
-    int last_index_of(const T& value) const {
+    // ps_ptr<char> str;
+    // str.assign("/audiofiles/my_playlist/podcast/h.mp3");
+    // int last = str.last_index_of('/');            // → 32 (the last '/')
+    // int prev = str.last_index_of('/', last - 1);  // → 23 (the second to last '/')
+
+    int last_index_of(const T& value, int start_pos = -1) const {
         if (!mem || allocated_size < sizeof(T)) return -1;
 
         std::size_t count = allocated_size / sizeof(T);
         T*          data = get();
-        for (int i = static_cast<int>(count) - 1; i >= 0; --i) {
+
+        if (start_pos < 0 || start_pos >= static_cast<int>(count)) start_pos = static_cast<int>(count) - 1;
+
+        for (int i = start_pos; i >= 0; --i) {
             if (data[i] == value) return i;
         }
         return -1;