From 067e8906be7bc8af2e4f5b7e642338b851e14780 Mon Sep 17 00:00:00 2001
From: Jared Roberts <jaredr@gmail.com>
Date: Mon, 19 Sep 2016 03:00:54 -0700
Subject: [PATCH] factor out ega loader

---
 src/bin/tileview.rs | 46 ++++++++--------------------------
 src/ega.rs          | 61 +++++++++++++++++++++++++++++++++++++++++++++
 src/lib.rs          |  3 +++
 3 files changed, 75 insertions(+), 35 deletions(-)
 create mode 100644 src/ega.rs

diff --git a/src/bin/tileview.rs b/src/bin/tileview.rs
index 66d9f38..8c21a10 100644
--- a/src/bin/tileview.rs
+++ b/src/bin/tileview.rs
@@ -1,30 +1,14 @@
+extern crate vrtue;
+use vrtue::ega;
+use vrtue::ega::{Compression, Tiling};
+
 extern crate image;
-extern crate itertools;
 
 use std::env;
 use std::io::Read;
 use std::path::Path;
 
-static EGA_PALETTE: [[u8; 4]; 16] = [[0x00, 0x00, 0x00, 0x00],
-                                     [0x00, 0x00, 0xAA, 0x00],
-                                     [0x00, 0xAA, 0x00, 0x00],
-                                     [0x00, 0xAA, 0xAA, 0x00],
-                                     [0xAA, 0x00, 0x00, 0x00],
-                                     [0xAA, 0x00, 0xAA, 0x00],
-                                     [0xAA, 0x55, 0x00, 0x00],
-                                     [0xAA, 0xAA, 0xAA, 0x00],
-                                     [0x55, 0x55, 0x55, 0x00],
-                                     [0x55, 0x55, 0xFF, 0x00],
-                                     [0x55, 0xFF, 0x55, 0x00],
-                                     [0x55, 0xFF, 0xFF, 0x00],
-                                     [0xFF, 0x55, 0x55, 0x00],
-                                     [0xFF, 0x55, 0xFF, 0x00],
-                                     [0xFF, 0xFF, 0x55, 0x00],
-                                     [0xFF, 0xFF, 0xFF, 0x00]];
-
-
-
-pub fn main() {
+fn main() {
   let args: Vec<String> = env::args().collect();
   let filename;
   if args.len() > 1 {
@@ -33,24 +17,16 @@ pub fn main() {
     filename = "data/SHAPES.EGA";
   }
 
-  let mut file = std::fs::File::open(Path::new(filename)).unwrap();
-  let mut tile_buf = [0u8; 128];
+  let mut file = std::fs::File::open(Path::new(filename))
+    .expect(&format!("failed opening EGA file: {}", filename));
+  let mut ega_vec = Vec::<u8>::new();
 
-  let mut i = 0;
-  while file.read_exact(&mut tile_buf).is_ok() {
-    let tilepixels = tile_buf.iter()
-        .flat_map(|tile_byte| {
-            EGA_PALETTE[(tile_byte >> 4u8 & 0xF) as usize]
-                .into_iter()
-                .chain(EGA_PALETTE[(tile_byte & 0xF) as usize]
-                    .into_iter())
-        })
-        .map(|x| *x)
-        .collect::<Vec<u8>>();
+  file.read_to_end(&mut ega_vec).expect("Read EGA file");
+  let ega_page = ega::decode(&ega_vec, Compression::UNCOMPRESSED, Tiling::TILED(16));
+  for (i, tilepixels) in ega_page.iter().enumerate() {
     let out_name = format!("out/{}.png", i);
     let out_file = std::fs::File::create(Path::new(&out_name)).expect("open out file");
     let enc = image::png::PNGEncoder::new(out_file);
     enc.encode(&tilepixels, 16, 16, image::ColorType::RGBA(8)).expect("write png");
-    i += 1;
   }
 }
diff --git a/src/ega.rs b/src/ega.rs
new file mode 100644
index 0000000..54c9710
--- /dev/null
+++ b/src/ega.rs
@@ -0,0 +1,61 @@
+static EGA_PALETTE: [[u8; 4]; 16] = [[0x00, 0x00, 0x00, 0x00],
+                                     [0x00, 0x00, 0xAA, 0x00],
+                                     [0x00, 0xAA, 0x00, 0x00],
+                                     [0x00, 0xAA, 0xAA, 0x00],
+                                     [0xAA, 0x00, 0x00, 0x00],
+                                     [0xAA, 0x00, 0xAA, 0x00],
+                                     [0xAA, 0x55, 0x00, 0x00],
+                                     [0xAA, 0xAA, 0xAA, 0x00],
+                                     [0x55, 0x55, 0x55, 0x00],
+                                     [0x55, 0x55, 0xFF, 0x00],
+                                     [0x55, 0xFF, 0x55, 0x00],
+                                     [0x55, 0xFF, 0xFF, 0x00],
+                                     [0xFF, 0x55, 0x55, 0x00],
+                                     [0xFF, 0x55, 0xFF, 0x00],
+                                     [0xFF, 0xFF, 0x55, 0x00],
+                                     [0xFF, 0xFF, 0xFF, 0x00]];
+
+pub enum Compression {
+  UNCOMPRESSED,
+  RLE,
+  LZW
+}
+
+pub enum Tiling {
+  UNTILED,
+  TILED(u16)
+}
+
+pub struct EgaPage {
+  pub data: Vec<u8>,
+  pub tilesize: u16,
+}
+
+impl EgaPage {
+  pub fn iter<'a>(&'a self) -> impl Iterator<Item=&'a [u8]> {
+    self.data.chunks(self.tilesize as usize)
+  }
+}
+
+pub fn decode<'a>(buf: &[u8], compression: Compression, tiling: Tiling)
+                  -> EgaPage {
+  let out: Vec<u8>;
+
+  out = match compression {
+    Compression::UNCOMPRESSED => buf.iter()
+                                    .flat_map(|tile_byte| {
+                                      EGA_PALETTE[(tile_byte >> 4u8 & 0xF) as usize]
+                                        .into_iter()
+                                        .chain(EGA_PALETTE[(tile_byte & 0xF) as usize]
+                                               .into_iter())
+                                    })
+                                    .map(|x| *x)
+                                    .collect(),
+    _ => unimplemented!()
+  };
+  let tilesize = match tiling {
+    Tiling::TILED(tiledim) => 4 * tiledim * tiledim,
+    Tiling::UNTILED => out.len() as u16
+  };
+  EgaPage { data: out, tilesize: tilesize}
+}
diff --git a/src/lib.rs b/src/lib.rs
index a4dd473..56c2b19 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,3 +1,6 @@
+#![feature(conservative_impl_trait)]
+
 #[macro_use] extern crate log;
 
+pub mod ega;
 pub mod vr;