1 files changed, 50 insertions, 0 deletions

diff --git a/src/decode.rs b/src/decode.rs
new file mode 100644
index 0000000..59dae97
--- /dev/null
+++ b/src/decode.rs
@@ -0,0 +1,50 @@
+use std::io::{self, Cursor, Read};
+
+use bitvec::prelude::*;
+use byteorder::{LittleEndian, ReadBytesExt};
+
+use crate::{FileHeader, Image, ImageInfoHeader};
+
+pub fn decode_image(obi_data: &mut Cursor<Vec<u8>>) -> io::Result<Image> {
+    // file header
+    let version = obi_data.read_u16::<LittleEndian>()?;
+    let file_size = obi_data.read_u32::<LittleEndian>()?;
+    let data_offset = obi_data.read_u32::<LittleEndian>()?;
+    let file_header = FileHeader {
+        version,
+        file_size,
+        data_offset,
+    };
+
+    // image info header
+    let width = obi_data.read_u32::<LittleEndian>()?;
+    let height = obi_data.read_u32::<LittleEndian>()?;
+    let compression_type = obi_data.read_u32::<LittleEndian>()?;
+    let post_compression_size = obi_data.read_u32::<LittleEndian>()?;
+    let image_info_header = ImageInfoHeader {
+        width,
+        height,
+        compression_type,
+        post_compression_size,
+    };
+
+    // pixmap data
+    let mut data_bytes = vec![];
+    obi_data.read_to_end(&mut data_bytes)?;
+    let data = data_bytes
+        .iter()
+        .map(|&b| {
+            BitVec::<Lsb0, u8>::from_element(b)
+                .into_iter()
+                .map(|e| e as bool)
+                .collect::<Vec<bool>>()
+        })
+        .flatten()
+        .collect::<Vec<_>>();
+
+    return Ok(Image {
+        file_header,
+        image_info_header,
+        data,
+    });
+}