From 3ebabc4fd5d8e69f16f28be6fe0b967a23b9745b Mon Sep 17 00:00:00 2001
From: Vincent Robert Weis <vrobweis@gmail.com>
Date: Thu, 24 Jun 2021 08:26:44 -0500
Subject: [PATCH] added file to support strongly typed IDs

---
 src/library/identifiers.rs | 136 +++++++++++++++++++++++++++++++++++++
 1 file changed, 136 insertions(+)
 create mode 100644 src/library/identifiers.rs

diff --git a/src/library/identifiers.rs b/src/library/identifiers.rs
new file mode 100644
index 0000000..cfb4ee5
--- /dev/null
+++ b/src/library/identifiers.rs
@@ -0,0 +1,136 @@
+trait ID: Sized + PartialEq + Eq + PartialOrd + Ord {}
+
+impl<T> ID for T where T: Sized + PartialEq + Eq + PartialOrd + Ord {}
+
+trait CompositeID<T, U>: ID where T: ID, U: ID {
+    fn new(id1: T, id2: U) -> Self;
+
+    fn get_first(&self) -> T;
+    fn get_second(&self) -> U;
+}
+
+type BookIDType = u8;
+type ChapterIDType = u16;
+type ContentIDType = u32;
+
+
+#[test]
+fn test_id_properties() {
+    let book: BookID = BookID::new(3);
+    let chapter: ChapterID = ChapterID::new(book.clone(), 7);
+    let content: ContentID = ContentID::new(chapter.clone(), 12);
+
+    assert_eq!(content.get_book_id(), book);
+    assert_eq!(content.get_chapter_id(), chapter.clone());
+    assert_eq!(chapter.get_book_id(), book);
+}
+
+
+#[repr(transparent)]
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
+struct BookID(BookIDType);
+
+impl BookID {
+    pub fn new(id_value: BookIDType) -> Self {
+        Self(id_value)
+    }
+}
+
+#[repr(transparent)]
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
+struct ChapterID(ChapterIDType);
+
+#[repr(transparent)]
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
+struct ContentID(u32);
+
+impl ChapterID {
+    fn get_book_id(&self) -> BookID {
+        self.get_first()
+    }
+}
+
+impl ContentID {
+    fn get_chapter_id(&self) -> ChapterID {
+        self.get_first()
+    }
+
+    fn get_book_id(&self) -> BookID {
+        self.get_chapter_id().get_book_id()
+    }
+}
+
+
+impl From<BookIDType> for BookID {
+    fn from(num: BookIDType) -> Self {
+        BookID(num)
+    }
+}
+
+impl From<ChapterIDType> for ChapterID {
+    fn from(num: ChapterIDType) -> Self {
+        ChapterID(num)
+    }
+}
+
+impl From<ContentIDType> for ContentID {
+    fn from(num: ContentIDType) -> Self {
+        ContentID(num)
+    }
+}
+
+
+impl CompositeID<BookID, u8> for ChapterID {
+    fn new(id1: BookID, id2: u8) -> Self {
+        Self( (((*id1) as u16) << 8) as u16 + (id2 as u16) )
+    }
+
+    fn get_first(&self) -> BookID {
+        BookID(((self.0 & 0xFF00) >> 8) as u8)
+    }
+
+    fn get_second(&self) -> u8 {
+        ((self.0 & 0xFF)) as u8
+    }
+}
+
+impl CompositeID<ChapterID, u16> for ContentID {
+    fn new(id1: ChapterID, id2: u16) -> Self {
+        Self( (((*id1) as u32) << 16) as u32 + (id2 as u32) )
+    }
+
+    fn get_first(&self) -> ChapterID {
+        ChapterID(((self.0 & 0xFFFF0000) >> 16) as u16)
+    }
+
+    fn get_second(&self) -> u16 {
+        ((self.0 & 0xFFFF)) as u16
+    }
+}
+
+
+use std::ops::Deref;
+
+impl Deref for BookID {
+    type Target = BookIDType;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl Deref for ChapterID {
+    type Target = ChapterIDType;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl Deref for ContentID {
+    type Target = ContentIDType;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
\ No newline at end of file