Refactor code into modules

.editorconfig

@@ -0,0 +1,10 @@
+root = true
+
+[*]
+end_of_line = lf
+insert_final_newline = true
+
+[*.rs]
+charset = utf-8
+indent_style = space
+indent_size = 4

CHANGELOG.md

@@ -1,5 +1,6 @@
-**Version 0.8.3**
- - Significant refactoring
+**Version 0.9.0 (unreleased)**
+ - [SEMVER_MAJOR] Significant refactoring of modules
+ - Use `itertools` to cleanup areas of code
 
 **Version 0.8.2**
  - Fix issue where images smaller than 4px width would crash on interlacing ([#42](https://github.com/shssoichiro/oxipng/issues/42))

Cargo.toml

@@ -34,7 +34,15 @@ num_cpus = "^0.2.11"
 regex = "^0.1.63"
 scoped-pool = "^0.1.8"
 
+[dependencies.clippy]
+optional = true
+version = "*"
+
 [dev-dependencies.image]
 version = "^0.8.0"
 default-features = false
 features = ["png_codec"]
+
+[features]
+default = []
+nightly = ["clippy", "regex/simd-accel"]

src/colors.rs

@@ -0,0 +1,96 @@
+use std::fmt;
+
+#[derive(Debug,PartialEq,Clone,Copy)]
+/// The color type used to represent this image
+pub enum ColorType {
+    /// Grayscale, with one color channel
+    Grayscale,
+    /// RGB, with three color channels
+    RGB,
+    /// Indexed, with one byte per pixel representing one of up to 256 colors in the image
+    Indexed,
+    /// Grayscale + Alpha, with two color channels
+    GrayscaleAlpha,
+    /// RGBA, with four color channels
+    RGBA,
+}
+
+impl fmt::Display for ColorType {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f,
+               "{}",
+               match *self {
+                   ColorType::Grayscale => "Grayscale",
+                   ColorType::RGB => "RGB",
+                   ColorType::Indexed => "Indexed",
+                   ColorType::GrayscaleAlpha => "Grayscale + Alpha",
+                   ColorType::RGBA => "RGB + Alpha",
+               })
+    }
+}
+
+impl ColorType {
+    /// Get the code used by the PNG specification to denote this color type
+    pub fn png_header_code(&self) -> u8 {
+        match *self {
+            ColorType::Grayscale => 0,
+            ColorType::RGB => 2,
+            ColorType::Indexed => 3,
+            ColorType::GrayscaleAlpha => 4,
+            ColorType::RGBA => 6,
+        }
+    }
+}
+
+#[derive(Debug,PartialEq,Clone,Copy)]
+/// The number of bits to be used per channel per pixel
+pub enum BitDepth {
+    /// One bit per channel per pixel
+    One,
+    /// Two bits per channel per pixel
+    Two,
+    /// Four bits per channel per pixel
+    Four,
+    /// Eight bits per channel per pixel
+    Eight,
+    /// Sixteen bits per channel per pixel
+    Sixteen,
+}
+
+impl fmt::Display for BitDepth {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f,
+               "{}",
+               match *self {
+                   BitDepth::One => "1",
+                   BitDepth::Two => "2",
+                   BitDepth::Four => "4",
+                   BitDepth::Eight => "8",
+                   BitDepth::Sixteen => "16",
+               })
+    }
+}
+
+impl BitDepth {
+    /// Retrieve the number of bits per channel per pixel as a `u8`
+    pub fn as_u8(&self) -> u8 {
+        match *self {
+            BitDepth::One => 1,
+            BitDepth::Two => 2,
+            BitDepth::Four => 4,
+            BitDepth::Eight => 8,
+            BitDepth::Sixteen => 16,
+        }
+    }
+    /// Parse a number of bits per channel per pixel into a `BitDepth`
+    pub fn from_u8(depth: u8) -> BitDepth {
+        match depth {
+            1 => BitDepth::One,
+            2 => BitDepth::Two,
+            4 => BitDepth::Four,
+            8 => BitDepth::Eight,
+            16 => BitDepth::Sixteen,
+            _ => panic!("Unsupported bit depth"),
+        }
+    }
+}