3 files changed, 49 insertions, 18 deletions

diff --git a/src/ffi.c b/src/ffi.c
new file mode 100644
index 0000000..a4af5ba
--- /dev/null
+++ b/src/ffi.c
@@ -0,0 +1,12 @@
+#include <stdlib.h>
+#include "../libvt100/src/vt100.h"
+
+int vt100_wrapper_rows(VT100Screen *vt)
+{
+    return vt->grid->max.row;
+}
+
+int vt100_wrapper_cols(VT100Screen *vt)
+{
+    return vt->grid->max.col;
+}
diff --git a/src/ffi.rs b/src/ffi.rs
index ceb8f35..47281ba 100644
--- a/src/ffi.rs
+++ b/src/ffi.rs
@@ -21,6 +21,9 @@ extern "C" {
         outp: *mut *mut libc::c_char,
         outlen: *mut libc::size_t,
     );
+
+    pub fn vt100_wrapper_rows(screen: *mut types::ScreenImpl) -> libc::c_int;
+    pub fn vt100_wrapper_cols(screen: *mut types::ScreenImpl) -> libc::c_int;
 }
 
 #[cfg(test)]
diff --git a/src/screen.rs b/src/screen.rs
index 698a6af..296f2dc 100644
--- a/src/screen.rs
+++ b/src/screen.rs
@@ -4,29 +4,31 @@ use std;
 use ffi;
 use types;
 
-pub struct Screen {
-    pub rows: i32,
-    pub cols: i32,
-
-    screen_impl: *mut types::ScreenImpl,
-}
+pub struct Screen(*mut types::ScreenImpl);
 
 impl Screen {
     pub fn new(rows: i32, cols: i32) -> Screen {
         let screen_impl = unsafe {
             ffi::vt100_screen_new(rows as libc::c_int, cols as libc::c_int)
         };
-        Screen {
-            rows: rows,
-            cols: cols,
-            screen_impl: screen_impl,
-        }
+        Screen(screen_impl)
+    }
+
+    pub fn rows(&self) -> i32 {
+        let Screen(screen_impl) = *self;
+        unsafe { ffi::vt100_wrapper_rows(screen_impl) }
+    }
+
+    pub fn cols(&self) -> i32 {
+        let Screen(screen_impl) = *self;
+        unsafe { ffi::vt100_wrapper_cols(screen_impl) }
     }
 
     pub fn process(&mut self, s: &str) -> u64 {
+        let Screen(screen_impl) = *self;
         unsafe {
             ffi::vt100_screen_process_string(
-                self.screen_impl,
+                screen_impl,
                 s.as_ptr() as *const libc::c_char,
                 s.len()
             ) as u64
@@ -39,10 +41,23 @@ impl Screen {
         row_end: i32,
         col_end: i32
     ) -> String {
-        let row_start = std::cmp::min(std::cmp::max(row_start, 0), self.rows - 1);
-        let col_start = std::cmp::min(std::cmp::max(col_start, 0), self.cols - 1);
-        let row_end = std::cmp::min(std::cmp::max(row_end, 0), self.rows - 1);
-        let col_end = std::cmp::min(std::cmp::max(col_end, 0), self.cols - 1);
+        let Screen(screen_impl) = *self;
+        let row_start = std::cmp::min(
+            std::cmp::max(row_start, 0),
+            self.rows() - 1
+        );
+        let col_start = std::cmp::min(
+            std::cmp::max(col_start, 0),
+            self.cols() - 1
+        );
+        let row_end = std::cmp::min(
+            std::cmp::max(row_end, 0),
+            self.rows() - 1
+        );
+        let col_end = std::cmp::min(
+            std::cmp::max(col_end, 0),
+            self.cols() - 1
+        );
 
         let start_loc = types::Loc { row: row_start, col: col_start };
         let end_loc = types::Loc { row: row_end, col: col_end };
@@ -51,7 +66,7 @@ impl Screen {
         let mut len: libc::size_t = unsafe { std::mem::uninitialized() };
         unsafe {
             ffi::vt100_screen_get_string_plaintext(
-                self.screen_impl,
+                screen_impl,
                 &start_loc as *const types::Loc,
                 &end_loc as *const types::Loc,
                 &mut plaintext as *mut *mut libc::c_char,
@@ -70,6 +85,7 @@ impl Screen {
 
 impl Drop for Screen {
     fn drop(&mut self) {
-        unsafe { ffi::vt100_screen_delete(self.screen_impl) };
+        let Screen(screen_impl) = *self;
+        unsafe { ffi::vt100_screen_delete(screen_impl) };
     }
 }