From 097d6a973ca08ccaa86e6bbee95d6f8b67a79d19 Mon Sep 17 00:00:00 2001
From: Jon Janzen <jon@endofeternity.ca>
Date: Tue, 10 Nov 2020 15:17:08 -0700
Subject: [PATCH] Created binary_loader

---
 binary_loader/Cargo.toml |  9 +++++
 binary_loader/src/lib.rs | 79 ++++++++++++++++++++++++++++++++++++++++
 db/Cargo.toml            |  1 +
 db/src/lib.rs            | 28 ++++++++++++++
 4 files changed, 117 insertions(+)
 create mode 100644 binary_loader/Cargo.toml
 create mode 100644 binary_loader/src/lib.rs

diff --git a/binary_loader/Cargo.toml b/binary_loader/Cargo.toml
new file mode 100644
index 0000000..4a152d9
--- /dev/null
+++ b/binary_loader/Cargo.toml
@@ -0,0 +1,9 @@
+[package]
+name = "binary_loader"
+version = "0.1.0"
+authors = ["Jon Janzen <jon@endofeternity.ca>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
diff --git a/binary_loader/src/lib.rs b/binary_loader/src/lib.rs
new file mode 100644
index 0000000..ab979af
--- /dev/null
+++ b/binary_loader/src/lib.rs
@@ -0,0 +1,79 @@
+pub fn load_high_u4(raw: u8) -> u8 {
+    (raw & 0xF0) >> 4
+}
+
+pub fn load_low_u4(raw: u8) -> u8 {
+    raw & 0x0F
+}
+
+pub fn load_u8(raw: u8) -> u8 {
+    raw
+}
+
+pub fn load_u32(raw: [u8; 4]) -> u32 {
+    let mut value: u32 = 0;
+    let temp: u32 = raw[0].into();
+    value = temp << 24;
+    let temp: u32 = raw[1].into();
+    value |= temp << 16;
+    let temp: u32 = raw[2].into();
+    value |= temp << 8;
+    let temp: u32 = raw[3].into();
+    value |= temp;
+    value
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn load_0() {
+        assert_eq!(0, load_u32([0, 0, 0, 0]));
+    }
+    
+    #[test]
+    fn load_1() {
+        assert_eq!(1, load_u32([0, 0, 0, 1]));
+    }
+    
+    #[test]
+    fn load_big() {
+        assert_eq!(0x01000000, load_u32([1, 0, 0, 0]));
+    }
+
+    #[test]
+    fn test_load_low_u4() {
+        assert_eq!(0x07, load_low_u4(0x07));
+    }
+    
+    #[test]
+    fn load_low_u4_with_high_data() {
+        assert_eq!(0x03, load_low_u4(0x13));
+    }
+
+    #[test]
+    fn load_low_u4_with_only_high_data() {
+        assert_eq!(0x00, load_low_u4(0x30));
+    }
+
+    #[test]
+    fn test_load_high_u4() {
+        assert_eq!(0x07, load_high_u4(0x70));
+    }
+    
+    #[test]
+    fn load_high_u4_with_low_data() {
+        assert_eq!(0x01, load_high_u4(0x13));
+    }
+
+    #[test]
+    fn load_high_u4_with_only_low_data() {
+        assert_eq!(0x00, load_high_u4(0x03));
+    }
+
+    #[test]
+    fn test_load_u8() {
+        assert_eq!(0x43, load_u8(0x43));
+    }
+}
diff --git a/db/Cargo.toml b/db/Cargo.toml
index b85f1d6..8b07935 100644
--- a/db/Cargo.toml
+++ b/db/Cargo.toml
@@ -7,3 +7,4 @@ edition = "2018"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+binary_loader = { path = "../binary_loader" }
\ No newline at end of file
diff --git a/db/src/lib.rs b/db/src/lib.rs
index 8fd15ea..8d72543 100644
--- a/db/src/lib.rs
+++ b/db/src/lib.rs
@@ -6,6 +6,27 @@ struct DBHeader {
     record_count: u32,
 }
 
+impl DBHeader {
+    fn from(raw: [u8; 8]) -> DBHeader {
+        
+        let mut reserved : u16 = 0x0000;
+        reserved = raw[2].into();
+        reserved <<= 8;
+        let temp : u16 = raw[3].into();
+        reserved |= temp;
+
+        let mut record_count : u32 = 0x00000000;
+
+        DBHeader {
+            magic: raw[0],
+            major_version: (raw[1] | 0xF0) >> 4,
+            minor_version: (raw[1] | 0x0F),
+            reserved: reserved,
+            record_count: record_count,
+        }
+    }
+}
+
 struct RecordHeader {
     field_count: u8,
     length: u8,
@@ -23,4 +44,11 @@ mod tests {
     fn it_works() {
         assert_eq!(2 + 2, 4);
     }
+    
+    #[test]
+    fn load_empty_db_header() {
+        let header = [0xDB, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00];
+        let db_header = DBHeader::from(header);
+        assert_eq!(db_header.magic, 0xDB);
+    }
 }