1 files changed, 34 insertions, 0 deletions

diff --git a/src/encode.rs b/src/encode.rs
new file mode 100644
index 0000000..24d3792
--- /dev/null
+++ b/src/encode.rs
@@ -0,0 +1,34 @@
+use std::io;
+
+use bitvec::prelude::*;
+use bitvec::slice::BitSlice;
+use byteorder::{LittleEndian, WriteBytesExt};
+
+use crate::Image;
+
+pub fn encode_image(obi_image: Image) -> io::Result<Vec<u8>> {
+    let mut obi_data = Vec::with_capacity(obi_image.file_header.file_size as usize);
+
+    // file header
+    let file_header = obi_image.file_header;
+    obi_data.write_u16::<LittleEndian>(file_header.version)?;
+    obi_data.write_u32::<LittleEndian>(file_header.file_size)?;
+    obi_data.write_u32::<LittleEndian>(file_header.data_offset)?;
+
+    // image info header
+    let image_info_header = obi_image.image_info_header;
+    obi_data.write_u32::<LittleEndian>(image_info_header.width)?;
+    obi_data.write_u32::<LittleEndian>(image_info_header.height)?;
+    obi_data.write_u32::<LittleEndian>(image_info_header.compression_type)?;
+    obi_data.write_u32::<LittleEndian>(image_info_header.post_compression_size)?;
+
+    // pixmap data
+    let pixmap = obi_image.data;
+    for byte in pixmap.chunks(8) {
+        let bits_as_u8 = byte.iter().map(|&e| e as u8).collect::<Vec<_>>();
+        let slice = BitSlice::<Lsb0, _>::from_slice(&bits_as_u8).unwrap();
+        obi_data.write_u8(slice.load::<u8>())?;
+    }
+
+    return Ok(obi_data);
+}