axl_strrev

axl_string.c

@@ -164,3 +164,25 @@ i8* axl_strstr(const i8* str, const i8* substr)
 
     return NULL;
 }
+
+i8* axl_strrev(i8* str)
+{
+    if(!str)
+    {
+        return NULL;
+    }
+
+    i8* start = str;
+    i8* end = str + axl_strlen(str) - 1;
+
+    while(start < end)
+    {
+        i8 tmp = *start;
+        *start = *end;
+        *end = tmp;
+        start++;
+        end--;
+    }
+    
+    return str;
+}

axl_string.h

@@ -11,5 +11,6 @@ i32       axl_strcmp(const i8* s1, const i8* s2);
 i32       axl_strncmp(const i8* s1, const i8* s2, u32 n);
 const i8* axl_strchr(const i8* str, i8 c);
 i8*       axl_strstr(const i8* str, const i8* substr);
+i8*       axl_strrev(i8* str);
 
 #endif // AXL_STRING

axl_string_test.c

@@ -440,6 +440,113 @@ KOAN(strstr_special_chars)
     ASSERT_PTR_EQ(str + 11, axl_strstr(str, "\n"));
 }
 
+KOAN(strrev_null)
+{
+    ASSERT_NULL(axl_strrev(NULL));
+}
+
+KOAN(strrev_empty)
+{
+    i8 str[] = "";
+    i8* result = axl_strrev(str);
+    ASSERT_PTR_EQ(str, result);
+    ASSERT_STR_EQ("", str);
+}
+
+KOAN(strrev_single_char)
+{
+    i8 str[] = "a";
+    i8* result = axl_strrev(str);
+    ASSERT_PTR_EQ(str, result);
+    ASSERT_STR_EQ("a", str);
+}
+
+KOAN(strrev_two_chars)
+{
+    i8 str[] = "ab";
+    i8* result = axl_strrev(str);
+    ASSERT_PTR_EQ(str, result);
+    ASSERT_STR_EQ("ba", str);
+}
+
+KOAN(strrev_odd_length)
+{
+    i8 str[] = "hello";
+    i8* result = axl_strrev(str);
+    ASSERT_PTR_EQ(str, result);
+    ASSERT_STR_EQ("olleh", str);
+}
+
+KOAN(strrev_even_length)
+{
+    i8 str[] = "world";
+    i8* result = axl_strrev(str);
+    ASSERT_PTR_EQ(str, result);
+    ASSERT_STR_EQ("dlrow", str);
+}
+
+KOAN(strrev_palindrome)
+{
+    i8 str[] = "racecar";
+    i8* result = axl_strrev(str);
+    ASSERT_PTR_EQ(str, result);
+    ASSERT_STR_EQ("racecar", str);
+}
+
+KOAN(strrev_with_spaces)
+{
+    i8 str[] = "hello world";
+    i8* result = axl_strrev(str);
+    ASSERT_PTR_EQ(str, result);
+    ASSERT_STR_EQ("dlrow olleh", str);
+}
+
+KOAN(strrev_with_special_chars)
+{
+    i8 str[] = "a\nb\tc";
+    i8* result = axl_strrev(str);
+    ASSERT_PTR_EQ(str, result);
+    ASSERT_STR_EQ("c\tb\na", str);
+}
+
+KOAN(strrev_numbers)
+{
+    i8 str[] = "123456789";
+    i8* result = axl_strrev(str);
+    ASSERT_PTR_EQ(str, result);
+    ASSERT_STR_EQ("987654321", str);
+}
+
+KOAN(strrev_mixed)
+{
+    i8 str[] = "a1b2c3";
+    i8* result = axl_strrev(str);
+    ASSERT_PTR_EQ(str, result);
+    ASSERT_STR_EQ("3c2b1a", str);
+}
+
+KOAN(strrev_long_string)
+{
+    i8 str[] = "abcdefghijklmnopqrstuvwxyz";
+    i8* result = axl_strrev(str);
+    ASSERT_PTR_EQ(str, result);
+    ASSERT_STR_EQ("zyxwvutsrqponmlkjihgfedcba", str);
+}
+
+KOAN(strrev_in_place)
+{
+    i8 str[] = "test";
+    i8* original_ptr = str;
+    i8* result = axl_strrev(str);
+    ASSERT_PTR_EQ(original_ptr, result);
+    ASSERT_STR_EQ("tset", str);
+    
+    // Reverse again to get back original
+    result = axl_strrev(str);
+    ASSERT_PTR_EQ(original_ptr, result);
+    ASSERT_STR_EQ("test", str);
+}
+
 int main(void)
 {
     axl_init();