adding atoi_superscript and isdigit_superscript

srcs/ft_atoll_superscript.c

@@ -0,0 +1,65 @@
+
+#include "libft.h"
+
+/**
+ * Parses a string of superscript digits (e.g., "²³⁴") into a long long.
+ * Returns the integer value, or LLONG_MAX/LLONG_MIN on overflow.
+ */
+long long ft_atoll_superscript(const char *str)
+{
+    long long nbr = 0;
+    int i = 0;
+    int negatif = 1;
+    int superscript_size;
+
+    // Skip leading whitespace
+    while (ft_isspace(str[i]))
+        i++;
+
+    // Handle optional sign
+    if (str[i] == '-')
+        negatif = -1;
+    if (str[i] == '+' || str[i] == '-')
+        i++;
+
+    // Parse superscript digits
+    while (1)
+    {
+        if (!ft_isdigit_superscript(&str[i], &superscript_size))
+            break; // Not a superscript digit
+
+        // Extract the digit value (0-9) from the superscript character
+        int digit;
+        if (superscript_size == 2)
+        {
+            // ² (U+00B2) or ³ (U+00B3)
+            if ((uint8_t)str[i + 1] == 0xB2)
+                digit = 2;
+            else if ((uint8_t)str[i + 1] == 0xB3)
+                digit = 3;
+            else
+                break; // Invalid, should not happen
+        }
+        else if (superscript_size == 3)
+        {
+            // ⁰ (U+2070) to ⁹ (U+2079)
+            digit = (uint8_t)str[i + 2] - 0xB0; // 0xB0 → 0, 0xB1 → 1, ..., 0xB9 → 9
+        }
+        else
+        {
+            break; // Invalid, should not happen
+        }
+
+        // Check for overflow
+        if (nbr > LLONG_MAX / 10 ||
+            (nbr == LLONG_MAX / 10 && digit > LLONG_MAX % 10))
+        {
+            return (negatif > 0) ? LLONG_MAX : LLONG_MIN;
+        }
+
+        nbr = nbr * 10 + digit;
+        i += superscript_size; // Skip the entire UTF-8 character
+    }
+
+    return (nbr * negatif);
+}