More ffi for choices and the like

rust-ffi-demo/demo.c

@@ -35,6 +35,12 @@ int main() {
       storybook_advance_nooption(book);
       break;
     case (FOOTER_CHOICES):
+	    int n = storybook_get_num_choices(book);
+	    for (int i = 1; i <= n; i++) {
+		    Choice* choice = storybook_get_choice(book, i);
+		    printf("%d) %s\n", choice->option, choice->flavor);
+		    storybook_free_choice(choice);
+	    }
 	    uint32_t option;
 	    printf("Make a choice: ");
 	    scanf("%d", &option);

src/rust-base/src/lib.rs

@@ -13,12 +13,12 @@ pub struct Page {
 pub enum Footer {
     Ending,
     Goto(String),
-    Choices(HashMap<u32, Choice>),
+    Choices(HashMap<usize, Choice>),
 }
 
 #[derive(Debug, PartialEq)]
 pub struct Choice {
-    option: u32,
+    option: usize,
     flavor: String,
     redirect: String,
     stat_check: Option<StatCheck>,
@@ -130,7 +130,7 @@ impl Book {
             Footer::Choices(_) => panic!("No option for advance on choices page!"),
         }
     }
-    pub fn advance_option(&mut self, option: u32) {
+    pub fn advance_option(&mut self, option: usize) {
         let footer = &self.get_current().footer;
         match footer {
             Footer::Ending => panic!("Option provided for advance on ending page!"),
@@ -181,6 +181,34 @@ pub mod ffi {
         Choices,
     }
 
+    #[repr(C)]
+    pub struct Choice {
+        option: usize,
+        flavor: *const c_char,
+    }
+
+    #[repr(C)]
+    pub struct StatCheck {
+        stat: *const c_char,
+        value: i32,
+        rel: c_char,
+    }
+
+    #[repr(C)]
+    pub struct StatChange {
+        stat: *const c_char,
+        addend: i32,
+    }
+
+    impl Choice {
+        pub fn new(choice: &super::Choice) -> Self {
+            Choice {
+                option: choice.option,
+                flavor: CString::new(choice.flavor.clone()).unwrap().into_raw(),
+            }
+        }
+    }
+
     #[no_mangle]
     pub extern fn storybook_make_book(string: *const c_char) -> *mut Book {
         let string = unsafe {
@@ -245,10 +273,42 @@ pub mod ffi {
         
     }
     #[no_mangle]
-    pub extern fn storybook_advance_option(book: *mut Book, option: u32) {
+    pub extern fn storybook_advance_option(book: *mut Book, option: usize) {
         let book = get_book_from_ref(book);
         book.advance_option(option);
     }
+
+    #[no_mangle]
+    pub extern fn storybook_get_num_choices(book: *mut Book) -> usize {
+        let book = get_book_from_ref(book);
+        let footer = &book.get_current().footer;
+        if let super::Footer::Choices(choices) = footer {
+            choices.len()
+        } else {
+            panic!("Requested num choices but page is not choices.");
+        }
+    }
+
+    #[no_mangle]
+    pub extern fn storybook_get_choice(book: *mut Book, n: usize) -> *mut Choice {
+        let book = get_book_from_ref(book);
+        let footer = &book.get_current().footer;
+        if let super::Footer::Choices(choices) = footer {
+            let choice = choices.get(&n).expect("Requested option isn't present in choices.");
+            let choice = Choice::new(choice);
+            let choice = Box::from(choice);
+            Box::into_raw(choice)
+        } else {
+            panic!("Requested a choice but page is not choices.");
+        }
+    }
+
+    #[no_mangle]
+    pub extern fn storybook_free_choice(choice: *mut Choice) {
+        unsafe {
+            Box::from_raw(choice);
+        }
+    }
 }
 
 #[cfg(test)]