1 files changed, 101 insertions, 0 deletions
diff --git a/src/xcursor.rs b/src/xcursor.rs
new file mode 100644
index 0000000..ff6c3d6
--- /dev/null
+++ b/src/xcursor.rs
@@ -0,0 +1,101 @@
+#[derive(Debug, Clone)]
+pub struct ImageInfo {
+  pub r#type: u32,
+  pub subtype: u32,
+  pub width: u32,
+  pub height: u32,
+  pub xhot: u32,
+  pub yhot: u32,
+  pub delay: u32,
+  pub data: Vec<u8>,
+}
+
+pub struct XCursorEncoder {
+  pub images: Vec<ImageInfo>,
+}
+
+const MAGIC: [u8; 4] = [0x58, 0x63, 0x75, 0x72];
+const IMAGE_HEADER: [u8; 4] = [0x02, 0x00, 0xfd, 0xff];
+
+impl XCursorEncoder {
+  pub fn new(images: Vec<ImageInfo>) -> Self {
+    XCursorEncoder { images }
+  }
+
+  fn image_pos(&self, position: usize) -> usize {
+    let mut val = 12 * self.images.len() + 16;
+    for n in 0..position {
+      val += 36 + ((self.images[n].width as usize) * (self.images[n].height as usize) * 4)
+    }
+    val
+  }
+
+  pub fn pack(&mut self) -> Vec<u8> {
+    fn insert_bytes(data: &mut Vec<u8>, new_data: impl IntoIterator<Item = u8>) {
+      for int in new_data {
+        data.push(int);
+      }
+    }
+    fn insert_int(data: &mut Vec<u8>, int: u32) {
+      data.push((int & 0xff) as u8);
+      data.push(((int >> 8) & 0xff) as u8);
+      data.push(((int >> 16) & 0xff) as u8);
+      data.push(((int >> 24) & 0xff) as u8);
+    }
+
+    let mut data: Vec<u8> = Vec::new();
+
+    // File Header
+    {
+      // MAGIC string ("Xcur")
+      insert_bytes(&mut data, MAGIC);
+      // CARD32 bytes in this header
+      insert_int(&mut data, 16);
+      // CARD32 file version
+      insert_int(&mut data, 1);
+      // CARD32 number of toc entries
+      insert_int(&mut data, self.images.len().try_into().unwrap());
+    }
+
+    // ntoc entries
+    {
+      let mut img_idx: usize = 0;
+      for img in self.images.clone().into_iter() {
+        // Some header
+        insert_bytes(&mut data, IMAGE_HEADER);
+        // CARD32 type-specific label - size for images
+        insert_int(&mut data, img.r#type);
+        // CARD32 absolute byte position of table in file
+        insert_int(&mut data, self.image_pos(img_idx).try_into().unwrap());
+
+        img_idx += 1;
+      }
+    }
+
+    // images
+    {
+      for img in self.images.clone().into_iter() {
+        // Header Size (36)
+        insert_int(&mut data, 36);
+        // Image Type
+        insert_bytes(&mut data, IMAGE_HEADER);
+        // Subtype, for nominal size
+        insert_int(&mut data, img.subtype);
+        // Version
+        insert_int(&mut data, 1);
+        // Image dimensions
+        insert_int(&mut data, img.width);
+        insert_int(&mut data, img.height);
+        // Cursor positioning
+        insert_int(&mut data, img.xhot);
+        insert_int(&mut data, img.yhot);
+        // Milliseconds till next frame
+        insert_int(&mut data, img.delay);
+        // Raw image data
+        insert_bytes(&mut data, img.data);
+      }
+    }
+
+    data
+  }
+}