Update dependencies

When color option has been set to never, the squeeze indicator
character asterisk '*' should not be printed in color.

Fixes #63

.github/FUNDING.yml

@@ -0,0 +1 @@
+github: sharkdp

.travis.yml

@@ -18,7 +18,7 @@ matrix:
 
     # Minimum Rust supported channel.
     - os: linux
-      rust: 1.29.0
+      rust: 1.31.0
       env: TARGET=x86_64-unknown-linux-gnu
 
 
@@ -43,7 +43,7 @@ install:
 script:
   # Incorporate TARGET env var to the build and test process
   - cargo build --target $TARGET --verbose
-  #- cargo test --target $TARGET --verbose
+  - cargo test --target $TARGET --verbose
 
 before_deploy:
   - bash ci/before_deploy.bash

Cargo.lock

@@ -1,68 +1,77 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
 [[package]]
 name = "ansi_term"
 version = "0.11.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "winapi 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "ansi_term"
+version = "0.12.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "atty"
-version = "0.2.11"
+version = "0.2.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.46 (registry+https://github.com/rust-lang/crates.io-index)",
- "termion 1.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.62 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "bitflags"
-version = "1.0.4"
+version = "1.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "cc"
-version = "1.0.28"
+version = "1.0.45"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "cfg-if"
-version = "0.1.6"
+version = "0.1.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "clap"
-version = "2.32.0"
+version = "2.33.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "ansi_term 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "atty 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
- "bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "strsim 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "atty 0.2.13 (registry+https://github.com/rust-lang/crates.io-index)",
+ "bitflags 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "strsim 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "term_size 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "textwrap 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "unicode-width 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "textwrap 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode-width 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "vec_map 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "ctrlc"
-version = "3.1.1"
+version = "3.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "nix 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "nix 0.14.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "hexyl"
-version = "0.4.0"
+version = "0.6.0"
 dependencies = [
- "ansi_term 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "atty 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
- "clap 2.32.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "ctrlc 3.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ansi_term 0.12.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "atty 0.2.13 (registry+https://github.com/rust-lang/crates.io-index)",
+ "clap 2.33.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ctrlc 3.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -76,37 +85,24 @@ dependencies = [
 
 [[package]]
 name = "libc"
-version = "0.2.46"
+version = "0.2.62"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "nix"
-version = "0.11.0"
+version = "0.14.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "cc 1.0.28 (registry+https://github.com/rust-lang/crates.io-index)",
- "cfg-if 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.46 (registry+https://github.com/rust-lang/crates.io-index)",
+ "bitflags 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cc 1.0.45 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.62 (registry+https://github.com/rust-lang/crates.io-index)",
  "void 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
-[[package]]
-name = "redox_syscall"
-version = "0.1.50"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-
-[[package]]
-name = "redox_termios"
-version = "0.1.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "redox_syscall 0.1.50 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
 [[package]]
 name = "strsim"
-version = "0.7.0"
+version = "0.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -115,32 +111,22 @@ version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.46 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.62 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
-[[package]]
-name = "termion"
-version = "1.5.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "libc 0.2.46 (registry+https://github.com/rust-lang/crates.io-index)",
- "redox_syscall 0.1.50 (registry+https://github.com/rust-lang/crates.io-index)",
- "redox_termios 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
 [[package]]
 name = "textwrap"
-version = "0.10.0"
+version = "0.11.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "term_size 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "unicode-width 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode-width 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "unicode-width"
-version = "0.1.5"
+version = "0.1.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -160,7 +146,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "winapi"
-version = "0.3.6"
+version = "0.3.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "winapi-i686-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -184,26 +170,24 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [metadata]
 "checksum ansi_term 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ee49baf6cb617b853aa8d93bf420db2383fab46d314482ca2803b40d5fde979b"
-"checksum atty 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)" = "9a7d5b8723950951411ee34d271d99dddcc2035a16ab25310ea2c8cfd4369652"
-"checksum bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)" = "228047a76f468627ca71776ecdebd732a3423081fcf5125585bcd7c49886ce12"
-"checksum cc 1.0.28 (registry+https://github.com/rust-lang/crates.io-index)" = "bb4a8b715cb4597106ea87c7c84b2f1d452c7492033765df7f32651e66fcf749"
-"checksum cfg-if 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)" = "082bb9b28e00d3c9d39cc03e64ce4cea0f1bb9b3fde493f0cbc008472d22bdf4"
-"checksum clap 2.32.0 (registry+https://github.com/rust-lang/crates.io-index)" = "b957d88f4b6a63b9d70d5f454ac8011819c6efa7727858f458ab71c756ce2d3e"
-"checksum ctrlc 3.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "630391922b1b893692c6334369ff528dcc3a9d8061ccf4c803aa8f83cb13db5e"
+"checksum ansi_term 0.12.1 (registry+https://github.com/rust-lang/crates.io-index)" = "d52a9bb7ec0cf484c551830a7ce27bd20d67eac647e1befb56b0be4ee39a55d2"
+"checksum atty 0.2.13 (registry+https://github.com/rust-lang/crates.io-index)" = "1803c647a3ec87095e7ae7acfca019e98de5ec9a7d01343f611cf3152ed71a90"
+"checksum bitflags 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "8a606a02debe2813760609f57a64a2ffd27d9fdf5b2f133eaca0b248dd92cdd2"
+"checksum cc 1.0.45 (registry+https://github.com/rust-lang/crates.io-index)" = "4fc9a35e1f4290eb9e5fc54ba6cf40671ed2a2514c3eeb2b2a908dda2ea5a1be"
+"checksum cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)" = "4785bdd1c96b2a846b2bd7cc02e86b6b3dbf14e7e53446c4f54c92a361040822"
+"checksum clap 2.33.0 (registry+https://github.com/rust-lang/crates.io-index)" = "5067f5bb2d80ef5d68b4c87db81601f0b75bca627bc2ef76b141d7b846a3c6d9"
+"checksum ctrlc 3.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "c7dfd2d8b4c82121dfdff120f818e09fc4380b0b7e17a742081a89b94853e87f"
 "checksum kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "7507624b29483431c0ba2d82aece8ca6cdba9382bff4ddd0f7490560c056098d"
-"checksum libc 0.2.46 (registry+https://github.com/rust-lang/crates.io-index)" = "023a4cd09b2ff695f9734c1934145a315594b7986398496841c7031a5a1bbdbd"
-"checksum nix 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)" = "d37e713a259ff641624b6cb20e3b12b2952313ba36b6823c0f16e6cfd9e5de17"
-"checksum redox_syscall 0.1.50 (registry+https://github.com/rust-lang/crates.io-index)" = "52ee9a534dc1301776eff45b4fa92d2c39b1d8c3d3357e6eb593e0d795506fc2"
-"checksum redox_termios 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "7e891cfe48e9100a70a3b6eb652fef28920c117d366339687bd5576160db0f76"
-"checksum strsim 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "bb4f380125926a99e52bc279241539c018323fab05ad6368b56f93d9369ff550"
+"checksum libc 0.2.62 (registry+https://github.com/rust-lang/crates.io-index)" = "34fcd2c08d2f832f376f4173a231990fa5aef4e99fb569867318a227ef4c06ba"
+"checksum nix 0.14.1 (registry+https://github.com/rust-lang/crates.io-index)" = "6c722bee1037d430d0f8e687bbdbf222f27cc6e4e68d5caf630857bb2b6dbdce"
+"checksum strsim 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)" = "8ea5119cdb4c55b55d432abb513a0429384878c15dde60cc77b1c99de1a95a6a"
 "checksum term_size 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "9e5b9a66db815dcfd2da92db471106457082577c3c278d4138ab3e3b4e189327"
-"checksum termion 1.5.1 (registry+https://github.com/rust-lang/crates.io-index)" = "689a3bdfaab439fd92bc87df5c4c78417d3cbe537487274e9b0b2dce76e92096"
-"checksum textwrap 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)" = "307686869c93e71f94da64286f9a9524c0f308a9e1c87a583de8e9c9039ad3f6"
-"checksum unicode-width 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "882386231c45df4700b275c7ff55b6f3698780a650026380e72dabe76fa46526"
+"checksum textwrap 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)" = "d326610f408c7a4eb6f51c37c330e496b08506c9457c9d34287ecc38809fb060"
+"checksum unicode-width 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)" = "7007dbd421b92cc6e28410fe7362e2e0a2503394908f417b68ec8d1c364c4e20"
 "checksum vec_map 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)" = "05c78687fb1a80548ae3250346c3db86a80a7cdd77bda190189f2d0a0987c81a"
 "checksum void 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "6a02e4885ed3bc0f2de90ea6dd45ebcbb66dacffe03547fadbb0eeae2770887d"
 "checksum winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "167dc9d6949a9b857f3451275e911c3f44255842c1f7a76f33c55103a909087a"
-"checksum winapi 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)" = "92c1eb33641e276cfa214a0522acad57be5c56b10cb348b3c5117db75f3ac4b0"
+"checksum winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)" = "8093091eeb260906a183e6ae1abdba2ef5ef2257a21801128899c3fc699229c6"
 "checksum winapi-build 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "2d315eee3b34aca4797b2da6b13ed88266e6d612562a0c46390af8299fc699bc"
 "checksum winapi-i686-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
 "checksum winapi-x86_64-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"

Cargo.toml

@@ -7,13 +7,18 @@ license = "MIT/Apache-2.0"
 name = "hexyl"
 readme = "README.md"
 repository = "https://github.com/sharkdp/hexyl"
-version = "0.4.0"
+version = "0.6.0"
+edition = "2018"
 
 [dependencies]
-ansi_term = "0.11"
+ansi_term = "0.12"
 atty = "0.2"
 ctrlc = "3.1"
 
 [dependencies.clap]
 version = "2"
 features = ["suggestions", "color", "wrap_help"]
+
+[profile.release]
+lto = true
+codegen-units = 1

README.md

@@ -22,16 +22,16 @@ of bytes (NULL bytes, printable ASCII characters, ASCII whitespace characters, o
 ### On Debian-based systems
 
 ``` bash
-wget "https://github.com/sharkdp/hexyl/releases/download/v0.4.0/hexyl_0.4.0_amd64.deb"
-sudo dpkg -i hexyl_0.4.0_amd64.deb
+wget "https://github.com/sharkdp/hexyl/releases/download/v0.6.0/hexyl_0.6.0_amd64.deb"
+sudo dpkg -i hexyl_0.6.0_amd64.deb
 ```
 
 ### On Arch Linux
 
-You can install `hexyl` from [this AUR package](https://aur.archlinux.org/packages/hexyl/):
+You can install `hexyl` from [the official package repository](https://www.archlinux.org/packages/community/x86_64/hexyl/):
 
 ```
-yay -S hexyl
+pacman -S hexyl
 ```
 
 ### On macOS
@@ -46,6 +46,12 @@ brew install hexyl
 pkg install hexyl
 ```
 
+### Via Nix
+
+```
+nix-env -i hexyl
+```
+
 ### On other distributions
 
 Check out the [release page](https://github.com/sharkdp/hexyl/releases) for binary builds.
@@ -57,7 +63,7 @@ you use a terminal that supports ANSI escape sequences (like PowerShell on Windo
 
 ### Via cargo
 
-If you have Rust 1.29 or higher, you can install `hexyl` from source via `cargo`:
+If you have Rust 1.31 or higher, you can install `hexyl` from source via `cargo`:
 ```
 cargo install hexyl
 ```

src/bin/hexyl.rs

@@ -0,0 +1,166 @@
+#[macro_use]
+extern crate clap;
+
+use atty;
+use ctrlc;
+
+use std::fs::File;
+use std::io::{self, prelude::*};
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::Arc;
+
+use clap::{App, AppSettings, Arg};
+
+use atty::Stream;
+
+use hexyl::{BorderStyle, Printer};
+
+fn run() -> Result<(), Box<dyn std::error::Error>> {
+    let app = App::new(crate_name!())
+        .setting(AppSettings::ColorAuto)
+        .setting(AppSettings::ColoredHelp)
+        .setting(AppSettings::DeriveDisplayOrder)
+        .setting(AppSettings::UnifiedHelpMessage)
+        .version(crate_version!())
+        .about(crate_description!())
+        .arg(Arg::with_name("file").help("File to display"))
+        .arg(
+            Arg::with_name("length")
+                .short("n")
+                .long("length")
+                .takes_value(true)
+                .value_name("N")
+                .help("Read only N bytes from the input"),
+        )
+        .arg(
+            Arg::with_name("bytes")
+                .short("c")
+                .long("bytes")
+                .takes_value(true)
+                .value_name("N")
+                .help("An alias for -n/--length"),
+        )
+        .arg(
+            Arg::with_name("nosqueezing")
+                .short("v")
+                .long("no-squeezing")
+                .help(
+                    "Displays all input data. Otherwise any number of groups of output \
+                     lines which would be identical to the preceding group of lines, are \
+                     replaced with a line comprised of a single asterisk.",
+                ),
+        )
+        .arg(
+            Arg::with_name("color")
+                .long("color")
+                .takes_value(true)
+                .value_name("when")
+                .possible_values(&["always", "auto", "never"])
+                .default_value("always")
+                .help(
+                    "When to use colors. The auto-mode only displays colors if the output \
+                     goes to an interactive terminal",
+                ),
+        )
+        .arg(
+            Arg::with_name("border")
+                .long("border")
+                .takes_value(true)
+                .possible_values(&["unicode", "ascii", "none"])
+                .default_value("unicode")
+                .help("Whether to draw a border with unicode or ASCII characters, or none at all"),
+        )
+        .arg(
+            Arg::with_name("display_offset")
+                .short("o")
+                .long("display-offset")
+                .takes_value(true)
+                .value_name("OFFSET")
+                .help("Add OFFSET to the displayed file position."),
+        );
+
+    let matches = app.get_matches_safe()?;
+
+    let stdin = io::stdin();
+
+    let mut reader: Box<dyn Read> = match matches.value_of("file") {
+        Some(filename) => Box::new(File::open(filename)?),
+        None => Box::new(stdin.lock()),
+    };
+
+    let length_arg = matches.value_of("length").or(matches.value_of("bytes"));
+
+    if let Some(length) = length_arg.and_then(parse_hex_or_int) {
+        reader = Box::new(reader.take(length));
+    }
+
+    let show_color = match matches.value_of("color") {
+        Some("never") => false,
+        Some("auto") => atty::is(Stream::Stdout),
+        _ => true,
+    };
+
+    let border_style = match matches.value_of("border") {
+        Some("unicode") => BorderStyle::Unicode,
+        Some("ascii") => BorderStyle::Ascii,
+        _ => BorderStyle::None,
+    };
+
+    let squeeze = !matches.is_present("nosqueezing");
+
+    let display_offset = matches
+        .value_of("display_offset")
+        .and_then(parse_hex_or_int)
+        .unwrap_or(0);
+
+    // Set up Ctrl-C handler
+    let cancelled = Arc::new(AtomicBool::new(false));
+    let c = cancelled.clone();
+
+    ctrlc::set_handler(move || {
+        c.store(true, Ordering::SeqCst);
+    })
+    .expect("Error setting Ctrl-C handler");
+
+    let stdout = io::stdout();
+    let mut stdout_lock = stdout.lock();
+
+    let mut printer = Printer::new(&mut stdout_lock, show_color, border_style, squeeze);
+    printer.display_offset(display_offset as usize);
+    printer.print_all(&mut reader, Some(cancelled))?;
+
+    Ok(())
+}
+
+fn main() {
+    // Enable ANSI support for Windows
+    #[cfg(windows)]
+    let _ = ansi_term::enable_ansi_support();
+
+    let result = run();
+
+    if let Err(err) = result {
+        if let Some(clap_err) = err.downcast_ref::<clap::Error>() {
+            eprint!("{}", clap_err); // Clap errors already have newlines
+
+            match clap_err.kind {
+                // The exit code should not indicate an error for --help / --version
+                clap::ErrorKind::HelpDisplayed | clap::ErrorKind::VersionDisplayed => {
+                    std::process::exit(0)
+                }
+                _ => (),
+            }
+        } else {
+            eprintln!("Error: {}", err);
+        }
+        std::process::exit(1);
+    }
+}
+
+fn parse_hex_or_int(n: &str) -> Option<u64> {
+    if n.starts_with("0x") {
+        u64::from_str_radix(n.trim_start_matches("0x"), 16).ok()
+    } else {
+        n.parse::<u64>().ok()
+    }
+}

src/lib.rs

@@ -0,0 +1,513 @@
+pub mod squeezer;
+
+use std::io::{self, Read, Write};
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::Arc;
+
+use ansi_term::Color;
+use ansi_term::Color::Fixed;
+
+use crate::squeezer::{SqueezeAction, Squeezer};
+
+type Cancelled = Arc<AtomicBool>;
+
+const BUFFER_SIZE: usize = 256;
+
+const COLOR_NULL: Color = Fixed(242); // grey
+const COLOR_OFFSET: Color = Fixed(242); // grey
+const COLOR_ASCII_PRINTABLE: Color = Color::Cyan;
+const COLOR_ASCII_WHITESPACE: Color = Color::Green;
+const COLOR_ASCII_OTHER: Color = Color::Purple;
+const COLOR_NONASCII: Color = Color::Yellow;
+
+pub enum ByteCategory {
+    Null,
+    AsciiPrintable,
+    AsciiWhitespace,
+    AsciiOther,
+    NonAscii,
+}
+
+#[derive(Copy, Clone)]
+struct Byte(u8);
+
+impl Byte {
+    fn category(self) -> ByteCategory {
+        if self.0 == 0x00 {
+            ByteCategory::Null
+        } else if self.0.is_ascii_alphanumeric()
+            || self.0.is_ascii_punctuation()
+            || self.0.is_ascii_graphic()
+        {
+            ByteCategory::AsciiPrintable
+        } else if self.0.is_ascii_whitespace() {
+            ByteCategory::AsciiWhitespace
+        } else if self.0.is_ascii() {
+            ByteCategory::AsciiOther
+        } else {
+            ByteCategory::NonAscii
+        }
+    }
+
+    fn color(self) -> &'static Color {
+        use crate::ByteCategory::*;
+
+        match self.category() {
+            Null => &COLOR_NULL,
+            AsciiPrintable => &COLOR_ASCII_PRINTABLE,
+            AsciiWhitespace => &COLOR_ASCII_WHITESPACE,
+            AsciiOther => &COLOR_ASCII_OTHER,
+            NonAscii => &COLOR_NONASCII,
+        }
+    }
+
+    fn as_char(self) -> char {
+        use crate::ByteCategory::*;
+
+        match self.category() {
+            Null => '0',
+            AsciiPrintable => self.0 as char,
+            AsciiWhitespace if self.0 == 0x20 => ' ',
+            AsciiWhitespace => '_',
+            AsciiOther => '•',
+            NonAscii => '×',
+        }
+    }
+}
+
+struct BorderElements {
+    left_corner: char,
+    horizontal_line: char,
+    column_separator: char,
+    right_corner: char,
+}
+
+pub enum BorderStyle {
+    Unicode,
+    Ascii,
+    None,
+}
+
+impl BorderStyle {
+    fn header_elems(&self) -> Option<BorderElements> {
+        match self {
+            BorderStyle::Unicode => Some(BorderElements {
+                left_corner: '┌',
+                horizontal_line: '─',
+                column_separator: '┬',
+                right_corner: '┐',
+            }),
+            BorderStyle::Ascii => Some(BorderElements {
+                left_corner: '+',
+                horizontal_line: '-',
+                column_separator: '+',
+                right_corner: '+',
+            }),
+            BorderStyle::None => None,
+        }
+    }
+
+    fn footer_elems(&self) -> Option<BorderElements> {
+        match self {
+            BorderStyle::Unicode => Some(BorderElements {
+                left_corner: '└',
+                horizontal_line: '─',
+                column_separator: '┴',
+                right_corner: '┘',
+            }),
+            BorderStyle::Ascii => Some(BorderElements {
+                left_corner: '+',
+                horizontal_line: '-',
+                column_separator: '+',
+                right_corner: '+',
+            }),
+            BorderStyle::None => None,
+        }
+    }
+
+    fn outer_sep(&self) -> char {
+        match self {
+            BorderStyle::Unicode => '│',
+            BorderStyle::Ascii => '|',
+            BorderStyle::None => ' ',
+        }
+    }
+
+    fn inner_sep(&self) -> char {
+        match self {
+            BorderStyle::Unicode => '┊',
+            BorderStyle::Ascii => '|',
+            BorderStyle::None => ' ',
+        }
+    }
+}
+
+pub struct Printer<'a, Writer: Write> {
+    idx: usize,
+    /// The raw bytes used as input for the current line.
+    raw_line: Vec<u8>,
+    /// The buffered line built with each byte, ready to print to writer.
+    buffer_line: Vec<u8>,
+    writer: &'a mut Writer,
+    show_color: bool,
+    border_style: BorderStyle,
+    header_was_printed: bool,
+    byte_hex_table: Vec<String>,
+    byte_char_table: Vec<String>,
+    squeezer: Squeezer,
+    display_offset: usize,
+}
+
+impl<'a, Writer: Write> Printer<'a, Writer> {
+    pub fn new(
+        writer: &'a mut Writer,
+        show_color: bool,
+        border_style: BorderStyle,
+        use_squeeze: bool,
+    ) -> Printer<'a, Writer> {
+        Printer {
+            idx: 1,
+            raw_line: vec![],
+            buffer_line: vec![],
+            writer,
+            show_color,
+            border_style,
+            header_was_printed: false,
+            byte_hex_table: (0u8..=u8::max_value())
+                .map(|i| {
+                    let byte_hex = format!("{:02x} ", i);
+                    if show_color {
+                        Byte(i).color().paint(byte_hex).to_string()
+                    } else {
+                        byte_hex
+                    }
+                })
+                .collect(),
+            byte_char_table: (0u8..=u8::max_value())
+                .map(|i| {
+                    let byte_char = format!("{}", Byte(i).as_char());
+                    if show_color {
+                        Byte(i).color().paint(byte_char).to_string()
+                    } else {
+                        byte_char
+                    }
+                })
+                .collect(),
+            squeezer: Squeezer::new(use_squeeze),
+            display_offset: 0,
+        }
+    }
+
+    pub fn display_offset(&mut self, display_offset: usize) -> &mut Self {
+        self.display_offset = display_offset;
+        self
+    }
+
+    pub fn header(&mut self) {
+        if let Some(border_elements) = self.border_style.header_elems() {
+            let h = border_elements.horizontal_line;
+            let h8 = h.to_string().repeat(8);
+            let h25 = h.to_string().repeat(25);
+
+            writeln!(
+                self.writer,
+                "{l}{h8}{c}{h25}{c}{h25}{c}{h8}{c}{h8}{r}",
+                l = border_elements.left_corner,
+                c = border_elements.column_separator,
+                r = border_elements.right_corner,
+                h8 = h8,
+                h25 = h25
+            )
+            .ok();
+        }
+    }
+
+    pub fn footer(&mut self) {
+        if let Some(border_elements) = self.border_style.footer_elems() {
+            let h = border_elements.horizontal_line;
+            let h8 = h.to_string().repeat(8);
+            let h25 = h.to_string().repeat(25);
+
+            writeln!(
+                self.writer,
+                "{l}{h8}{c}{h25}{c}{h25}{c}{h8}{c}{h8}{r}",
+                l = border_elements.left_corner,
+                c = border_elements.column_separator,
+                r = border_elements.right_corner,
+                h8 = h8,
+                h25 = h25
+            )
+            .ok();
+        }
+    }
+
+    fn print_position_indicator(&mut self) {
+        if !self.header_was_printed {
+            self.header();
+            self.header_was_printed = true;
+        }
+
+        let style = COLOR_OFFSET.normal();
+        let byte_index = format!("{:08x}", (self.idx - 1) + self.display_offset);
+        let formatted_string = if self.show_color {
+            format!("{}", style.paint(byte_index))
+        } else {
+            byte_index
+        };
+        let _ = write!(
+            &mut self.buffer_line,
+            "{}{}{} ",
+            self.border_style.outer_sep(),
+            formatted_string,
+            self.border_style.outer_sep()
+        );
+    }
+
+    pub fn print_byte(&mut self, b: u8) -> io::Result<()> {
+        if self.idx % 16 == 1 {
+            self.print_position_indicator();
+        }
+
+        write!(&mut self.buffer_line, "{}", self.byte_hex_table[b as usize])?;
+        self.raw_line.push(b);
+
+        self.squeezer.process(b, self.idx);
+
+        match self.idx % 16 {
+            8 => {
+                let _ = write!(&mut self.buffer_line, "{} ", self.border_style.inner_sep());
+            }
+            0 => {
+                self.print_textline()?;
+            }
+            _ => {}
+        }
+
+        self.idx += 1;
+
+        Ok(())
+    }
+
+    pub fn print_textline(&mut self) -> io::Result<()> {
+        let len = self.raw_line.len();
+
+        if len == 0 {
+            if self.squeezer.active() {
+                self.print_position_indicator();
+                let _ = writeln!(
+                    &mut self.buffer_line,
+                    "{0:1$}{4}{0:2$}{5}{0:3$}{4}{0:3$}{5}",
+                    "",
+                    24,
+                    25,
+                    8,
+                    self.border_style.inner_sep(),
+                    self.border_style.outer_sep(),
+                );
+                self.writer.write_all(&self.buffer_line)?;
+            }
+            return Ok(());
+        }
+
+        let squeeze_action = self.squeezer.action();
+
+        if squeeze_action != SqueezeAction::Delete {
+            if len < 8 {
+                let _ = write!(
+                    &mut self.buffer_line,
+                    "{0:1$}{3}{0:2$}{4}",
+                    "",
+                    3 * (8 - len),
+                    1 + 3 * 8,
+                    self.border_style.inner_sep(),
+                    self.border_style.outer_sep(),
+                );
+            } else {
+                let _ = write!(
+                    &mut self.buffer_line,
+                    "{0:1$}{2}",
+                    "",
+                    3 * (16 - len),
+                    self.border_style.outer_sep()
+                );
+            }
+
+            let mut idx = 1;
+            for &b in self.raw_line.iter() {
+                let _ = write!(
+                    &mut self.buffer_line,
+                    "{}",
+                    self.byte_char_table[b as usize]
+                );
+
+                if idx == 8 {
+                    let _ = write!(&mut self.buffer_line, "{}", self.border_style.inner_sep());
+                }
+
+                idx += 1;
+            }
+
+            if len < 8 {
+                let _ = writeln!(
+                    &mut self.buffer_line,
+                    "{0:1$}{3}{0:2$}{4}",
+                    "",
+                    8 - len,
+                    8,
+                    self.border_style.inner_sep(),
+                    self.border_style.outer_sep(),
+                );
+            } else {
+                let _ = writeln!(
+                    &mut self.buffer_line,
+                    "{0:1$}{2}",
+                    "",
+                    16 - len,
+                    self.border_style.outer_sep()
+                );
+            }
+        }
+
+        match squeeze_action {
+            SqueezeAction::Print => {
+                self.buffer_line.clear();
+                let style = COLOR_OFFSET.normal();
+                let asterisk = if self.show_color {
+                    format!("{}", style.paint("*"))
+                } else {
+                    String::from("*")
+                };
+                let _ = writeln!(
+                    &mut self.buffer_line,
+                    "{5}{0}{1:2$}{5}{1:3$}{6}{1:3$}{5}{1:4$}{6}{1:4$}{5}",
+                    asterisk,
+                    "",
+                    7,
+                    25,
+                    8,
+                    self.border_style.outer_sep(),
+                    self.border_style.inner_sep(),
+                );
+            }
+            SqueezeAction::Delete => self.buffer_line.clear(),
+            SqueezeAction::Ignore => (),
+        }
+
+        self.writer.write_all(&self.buffer_line)?;
+
+        self.raw_line.clear();
+        self.buffer_line.clear();
+
+        self.squeezer.advance();
+
+        Ok(())
+    }
+
+    pub fn header_was_printed(&self) -> bool {
+        self.header_was_printed
+    }
+
+    /// Loop through the given `Reader`, printing until the `Reader` buffer
+    /// is exhausted, or the optional `cancelled` bool is set to true.
+    pub fn print_all<Reader: Read>(
+        &mut self,
+        mut reader: Reader,
+        canceller: Option<Cancelled>,
+    ) -> Result<(), Box<dyn std::error::Error>> {
+        let mut buffer = [0; BUFFER_SIZE];
+        'mainloop: loop {
+            let size = reader.read(&mut buffer)?;
+            if size == 0 {
+                break;
+            }
+
+            if let Some(cancelled) = &canceller {
+                if cancelled.load(Ordering::SeqCst) {
+                    eprintln!("hexyl has been cancelled.");
+                    std::process::exit(130); // Set exit code to 128 + SIGINT
+                }
+            }
+
+            for b in &buffer[..size] {
+                let res = self.print_byte(*b);
+
+                if res.is_err() {
+                    // Broken pipe
+                    break 'mainloop;
+                }
+            }
+        }
+
+        // Finish last line
+        self.print_textline().ok();
+        if !self.header_was_printed() {
+            self.header();
+        }
+        self.footer();
+
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::io;
+    use std::str;
+
+    use super::*;
+
+    fn assert_print_all_output<Reader: Read>(input: Reader, expected_string: String) -> () {
+        let mut output = vec![];
+        let mut printer = Printer::new(&mut output, false, BorderStyle::Unicode, true);
+
+        printer.print_all(input, None).unwrap();
+
+        let actual_string: &str = str::from_utf8(&output).unwrap();
+        assert_eq!(actual_string, expected_string)
+    }
+
+    #[test]
+    fn empty_file_passes() {
+        let input = io::empty();
+        let expected_string =
+            "┌────────┬─────────────────────────┬─────────────────────────┬────────┬────────┐
+└────────┴─────────────────────────┴─────────────────────────┴────────┴────────┘
+"
+            .to_owned();
+        assert_print_all_output(input, expected_string);
+    }
+
+    #[test]
+    fn short_input_passes() {
+        let input = io::Cursor::new(b"spam");
+        let expected_string =
+            "┌────────┬─────────────────────────┬─────────────────────────┬────────┬────────┐
+│00000000│ 73 70 61 6d             ┊                         │spam    ┊        │
+└────────┴─────────────────────────┴─────────────────────────┴────────┴────────┘
+"
+            .to_owned();
+        assert_print_all_output(input, expected_string);
+    }
+
+    #[test]
+    fn display_offset() {
+        let input = io::Cursor::new(b"spamspamspamspamspam");
+        let expected_string =
+            "┌────────┬─────────────────────────┬─────────────────────────┬────────┬────────┐
+│deadbeef│ 73 70 61 6d 73 70 61 6d ┊ 73 70 61 6d 73 70 61 6d │spamspam┊spamspam│
+│deadbeff│ 73 70 61 6d             ┊                         │spam    ┊        │
+└────────┴─────────────────────────┴─────────────────────────┴────────┴────────┘
+"
+            .to_owned();
+
+        let mut output = vec![];
+        let mut printer: Printer<Vec<u8>> =
+            Printer::new(&mut output, false, BorderStyle::Unicode, true);
+        printer.display_offset(0xdeadbeef);
+
+        printer.print_all(input, None).unwrap();
+
+        let actual_string: &str = str::from_utf8(&output).unwrap();
+        assert_eq!(actual_string, expected_string)
+    }
+}

src/main.rs

@@ -1,337 +0,0 @@
-#[macro_use]
-extern crate clap;
-extern crate ansi_term;
-extern crate atty;
-extern crate ctrlc;
-
-use std::fs::File;
-use std::io::{self, prelude::*, StdoutLock};
-use std::sync::atomic::{AtomicBool, Ordering};
-use std::sync::Arc;
-
-use clap::{App, AppSettings, Arg};
-
-use ansi_term::Color;
-use ansi_term::Color::Fixed;
-
-use atty::Stream;
-
-const BUFFER_SIZE: usize = 256;
-
-const COLOR_NULL: Color = Fixed(242); // grey
-const COLOR_OFFSET: Color = Fixed(242); // grey
-const COLOR_ASCII_PRINTABLE: Color = Color::Cyan;
-const COLOR_ASCII_WHITESPACE: Color = Color::Green;
-const COLOR_ASCII_OTHER: Color = Color::Purple;
-const COLOR_NONASCII: Color = Color::Yellow;
-
-enum ByteCategory {
-    Null,
-    AsciiPrintable,
-    AsciiWhitespace,
-    AsciiOther,
-    NonAscii,
-}
-
-#[derive(Copy, Clone)]
-struct Byte(u8);
-
-impl Byte {
-    fn category(self) -> ByteCategory {
-        if self.0 == 0x00 {
-            ByteCategory::Null
-        } else if self.0.is_ascii_alphanumeric()
-            || self.0.is_ascii_punctuation()
-            || self.0.is_ascii_graphic()
-        {
-            ByteCategory::AsciiPrintable
-        } else if self.0.is_ascii_whitespace() {
-            ByteCategory::AsciiWhitespace
-        } else if self.0.is_ascii() {
-            ByteCategory::AsciiOther
-        } else {
-            ByteCategory::NonAscii
-        }
-    }
-
-    fn color(self) -> &'static Color {
-        use ByteCategory::*;
-
-        match self.category() {
-            Null => &COLOR_NULL,
-            AsciiPrintable => &COLOR_ASCII_PRINTABLE,
-            AsciiWhitespace => &COLOR_ASCII_WHITESPACE,
-            AsciiOther => &COLOR_ASCII_OTHER,
-            NonAscii => &COLOR_NONASCII,
-        }
-    }
-
-    fn as_char(self) -> char {
-        use ByteCategory::*;
-
-        match self.category() {
-            Null => '0',
-            AsciiPrintable => self.0 as char,
-            AsciiWhitespace if self.0 == 0x20 => ' ',
-            AsciiWhitespace => '_',
-            AsciiOther => '•',
-            NonAscii => '×',
-        }
-    }
-}
-
-struct Printer<'a> {
-    idx: usize,
-    /// The raw bytes used as input for the current line.
-    raw_line: Vec<u8>,
-    /// The buffered line built with each byte, ready to print to stdout.
-    buffer_line: Vec<u8>,
-    stdout: StdoutLock<'a>,
-    show_color: bool,
-    byte_hex_table: Vec<String>,
-    byte_char_table: Vec<String>,
-}
-
-impl<'a> Printer<'a> {
-    fn new(stdout: StdoutLock, show_color: bool) -> Printer {
-        Printer {
-            idx: 1,
-            raw_line: vec![],
-            buffer_line: vec![],
-            stdout,
-            show_color,
-            byte_hex_table: (0u8..=u8::max_value())
-                .map(|i| {
-                    let byte_hex = format!("{:02x} ", i);
-                    if show_color {
-                        Byte(i).color().paint(byte_hex).to_string()
-                    } else {
-                        byte_hex
-                    }
-                })
-                .collect(),
-            byte_char_table: (0u8..=u8::max_value())
-                .map(|i| {
-                    let byte_char = format!("{}", Byte(i).as_char());
-                    if show_color {
-                        Byte(i).color().paint(byte_char).to_string()
-                    } else {
-                        byte_char
-                    }
-                })
-                .collect(),
-        }
-    }
-
-    fn header(&mut self) {
-        writeln!(
-            self.stdout,
-            "┌{0:─<8}┬{0:─<25}┬{0:─<25}┬{0:─<8}┬{0:─<8}┐",
-            ""
-        )
-        .ok();
-    }
-
-    fn footer(&mut self) {
-        writeln!(
-            self.stdout,
-            "└{0:─<8}┴{0:─<25}┴{0:─<25}┴{0:─<8}┴{0:─<8}┘",
-            ""
-        )
-        .ok();
-    }
-
-    fn print_byte(&mut self, b: u8) -> io::Result<()> {
-        if self.idx % 16 == 1 {
-            let style = COLOR_OFFSET.normal();
-            let byte_index = format!("{:08x}", self.idx - 1);
-            let formatted_string = if self.show_color {
-                format!("{}", style.paint(byte_index))
-            } else {
-                byte_index
-            };
-            let _ = write!(&mut self.buffer_line, "│{}│ ", formatted_string);
-        }
-
-        write!(&mut self.buffer_line, "{}", self.byte_hex_table[b as usize])?;
-        self.raw_line.push(b);
-
-        match self.idx % 16 {
-            8 => {
-                let _ = write!(&mut self.buffer_line, "┊ ");
-            }
-            0 => self.print_textline()?,
-            _ => {}
-        }
-
-        self.idx += 1;
-
-        Ok(())
-    }
-
-    fn print_textline(&mut self) -> io::Result<()> {
-        let len = self.raw_line.len();
-
-        if len == 0 {
-            return Ok(());
-        }
-
-        if len < 8 {
-            let _ = write!(
-                &mut self.buffer_line,
-                "{0:1$}┊{0:2$}│",
-                "",
-                3 * (8 - len),
-                1 + 3 * 8
-            );
-        } else {
-            let _ = write!(&mut self.buffer_line, "{0:1$}│", "", 3 * (16 - len));
-        }
-
-        let mut idx = 1;
-        for &b in self.raw_line.iter() {
-            let _ = write!(
-                &mut self.buffer_line,
-                "{}",
-                self.byte_char_table[b as usize]
-            );
-
-            if idx == 8 {
-                let _ = write!(&mut self.buffer_line, "┊");
-            }
-
-            idx += 1;
-        }
-
-        if len < 8 {
-            let _ = writeln!(&mut self.buffer_line, "{0:1$}┊{0:2$}│ ", "", 8 - len, 8);
-        } else {
-            let _ = writeln!(&mut self.buffer_line, "{0:1$}│", "", 16 - len);
-        }
-        self.stdout.write_all(&self.buffer_line)?;
-
-        self.raw_line.clear();
-        self.buffer_line.clear();
-
-        Ok(())
-    }
-}
-
-fn run() -> Result<(), Box<::std::error::Error>> {
-    let app = App::new(crate_name!())
-        .setting(AppSettings::ColorAuto)
-        .setting(AppSettings::ColoredHelp)
-        .setting(AppSettings::DeriveDisplayOrder)
-        .setting(AppSettings::UnifiedHelpMessage)
-        .version(crate_version!())
-        .about(crate_description!())
-        .arg(Arg::with_name("file").help("File to display"))
-        .arg(
-            Arg::with_name("length")
-                .short("n")
-                .long("length")
-                .takes_value(true)
-                .value_name("N")
-                .help("Read only N bytes from the input"),
-        )
-        .arg(
-            Arg::with_name("color")
-                .long("color")
-                .takes_value(true)
-                .value_name("when")
-                .possible_values(&["always", "auto", "never"])
-                .default_value("always")
-                .help(
-                    "When to use colors. The auto-mode only displays colors if the output \
-                     goes to an interactive terminal",
-                ),
-        );
-
-    let matches = app.get_matches_safe()?;
-
-    let stdin = io::stdin();
-
-    let mut reader: Box<dyn Read> = match matches.value_of("file") {
-        Some(filename) => Box::new(File::open(filename)?),
-        None => Box::new(stdin.lock()),
-    };
-
-    if let Some(length) = matches
-        .value_of("length")
-        .and_then(|n| n.parse::<u64>().ok())
-    {
-        reader = Box::new(reader.take(length));
-    }
-
-    let show_color = match matches.value_of("color") {
-        Some("never") => false,
-        Some("auto") => atty::is(Stream::Stdout),
-        _ => true,
-    };
-
-    // Set up Ctrl-C handler
-    let cancelled = Arc::new(AtomicBool::new(false));
-    let c = cancelled.clone();
-
-    ctrlc::set_handler(move || {
-        c.store(true, Ordering::SeqCst);
-    })
-    .expect("Error setting Ctrl-C handler");
-
-    let stdout = io::stdout();
-    let mut printer = Printer::new(stdout.lock(), show_color);
-    printer.header();
-
-    let mut buffer = [0; BUFFER_SIZE];
-    'mainloop: loop {
-        let size = reader.read(&mut buffer)?;
-        if size == 0 {
-            break;
-        }
-
-        if cancelled.load(Ordering::SeqCst) {
-            eprintln!("hexyl has been cancelled.");
-            std::process::exit(130); // Set exit code to 128 + SIGINT
-        }
-
-        for b in &buffer[..size] {
-            let res = printer.print_byte(*b);
-
-            if res.is_err() {
-                // Broken pipe
-                break 'mainloop;
-            }
-        }
-    }
-
-    // Finish last line
-    printer.print_textline().ok();
-    printer.footer();
-
-    Ok(())
-}
-
-fn main() {
-    // Enable ANSI support for Windows
-    #[cfg(windows)]
-    let _ = ansi_term::enable_ansi_support();
-
-    let result = run();
-
-    if let Err(err) = result {
-        if let Some(clap_err) = err.downcast_ref::<clap::Error>() {
-            eprint!("{}", clap_err); // Clap errors already have newlines
-
-            match clap_err.kind {
-                // The exit code should not indicate an error for --help / --version
-                clap::ErrorKind::HelpDisplayed | clap::ErrorKind::VersionDisplayed => {
-                    std::process::exit(0)
-                }
-                _ => (),
-            }
-        } else {
-            eprintln!("Error: {}", err);
-        }
-        std::process::exit(1);
-    }
-}

src/squeezer.rs

@@ -0,0 +1,423 @@
+#[derive(Debug, PartialEq)]
+enum SqueezeState {
+    /// not enabled
+    Disabled,
+    /// Will be set from all states if equal condition can't be hold up.
+    /// Set if previous byte is not equal the current processed byte.
+    NoSqueeze,
+    /// Valid for a whole line to identify if it is candidate for squeezing
+    Probe,
+    /// Squeeze line parsing is active, but EOL is not reached yet
+    SqueezeActive,
+    /// Squeeze line, EOL is reached, will influence the action
+    Squeeze,
+    /// same as Squeeze, however this is only for the first line after
+    /// the squeeze candidate has been set.
+    SqueezeFirstLine,
+    /// same as SqueezeActive, however this is only for the first line after
+    /// the squeeze candidate has been set.
+    SqueezeActiveFirstLine,
+}
+
+pub struct Squeezer {
+    state: SqueezeState,
+    byte: u8,
+}
+
+#[derive(Debug, PartialEq)]
+pub enum SqueezeAction {
+    Ignore,
+    Print,
+    Delete,
+}
+
+/// line size
+const LSIZE: usize = 16;
+
+impl Squeezer {
+    pub fn new(enabled: bool) -> Squeezer {
+        Squeezer {
+            state: if enabled {
+                SqueezeState::Probe
+            } else {
+                SqueezeState::Disabled
+            },
+            byte: 0,
+        }
+    }
+
+    pub fn process(&mut self, b: u8, i: usize) {
+        use self::SqueezeState::*;
+        if self.state == Disabled {
+            return;
+        }
+        let eq = b == self.byte;
+
+        if i % LSIZE == 0 {
+            if !eq {
+                self.state = Probe;
+            } else {
+                self.state = match self.state {
+                    NoSqueeze => Probe,
+                    Probe => SqueezeActiveFirstLine,
+                    SqueezeActiveFirstLine => SqueezeFirstLine,
+                    SqueezeFirstLine => SqueezeActive,
+                    SqueezeActive => Squeeze,
+                    Squeeze => SqueezeActive,
+                    Disabled => Disabled,
+                };
+            }
+        } else if !eq {
+            if i % LSIZE == 1 {
+                self.state = Probe;
+            } else if i % LSIZE != 1 {
+                self.state = NoSqueeze;
+            }
+        }
+
+        self.byte = b;
+    }
+
+    pub fn active(&self) -> bool {
+        use self::SqueezeState::*;
+        match self.state {
+            Squeeze | SqueezeActive | SqueezeFirstLine | SqueezeActiveFirstLine => true,
+            _ => false,
+        }
+    }
+
+    pub fn action(&self) -> SqueezeAction {
+        match self.state {
+            SqueezeState::SqueezeFirstLine => SqueezeAction::Print,
+            SqueezeState::Squeeze => SqueezeAction::Delete,
+            _ => SqueezeAction::Ignore,
+        }
+    }
+
+    pub fn advance(&mut self) {
+        match self.state {
+            SqueezeState::SqueezeFirstLine => {
+                self.state = SqueezeState::SqueezeActive;
+            }
+            SqueezeState::Squeeze => {
+                self.state = SqueezeState::SqueezeActive;
+            }
+            _ => {}
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn three_same_lines() {
+        const LINES: usize = 3;
+        let v = vec![0u8; LINES * LSIZE];
+        let mut s = Squeezer::new(true);
+        // just initialized
+        assert_eq!(s.action(), SqueezeAction::Ignore);
+        s.advance();
+
+        let exp = vec![
+            SqueezeAction::Ignore, // first line, print as is
+            SqueezeAction::Print,  // print squeeze symbol
+            SqueezeAction::Delete, // delete reoccurring line
+        ];
+
+        let mut line = 0;
+        let mut idx = 1;
+        for z in v.chunks(LSIZE) {
+            for i in z {
+                s.process(*i, idx);
+                idx += 1;
+            }
+            let action = s.action();
+            s.advance();
+            assert_eq!(action, exp[line]);
+            line += 1;
+        }
+    }
+
+    #[test]
+    fn incomplete_while_squeeze() {
+        // fourth line only has 12 bytes and should be printed
+        let v = vec![0u8; 3 * LSIZE + 12];
+        let mut s = Squeezer::new(true);
+        // just initialized
+        assert_eq!(s.action(), SqueezeAction::Ignore);
+        s.advance();
+
+        let exp = vec![
+            SqueezeAction::Ignore, // first line, print as is
+            SqueezeAction::Print,  // print squeeze symbol
+            SqueezeAction::Delete, // delete reoccurring line
+            SqueezeAction::Ignore, // last line only 12 bytes, print it
+        ];
+
+        let mut line = 0;
+        let mut idx = 1;
+        for z in v.chunks(LSIZE) {
+            for i in z {
+                s.process(*i, idx);
+                idx += 1;
+            }
+            assert_eq!(s.action(), exp[line]);
+            s.advance();
+            line += 1;
+        }
+    }
+
+    #[test]
+    /// all three lines are different, print all
+    fn three_different_lines() {
+        let mut v: Vec<u8> = vec![];
+        v.extend(vec![0u8; 16]);
+        v.extend(vec![1u8; 16]);
+        v.extend(vec![2u8; 16]);
+
+        let mut s = Squeezer::new(true);
+        // just initialized
+        assert_eq!(s.action(), SqueezeAction::Ignore);
+        s.advance();
+
+        let exp = vec![
+            SqueezeAction::Ignore, // first line, print as is
+            SqueezeAction::Ignore, // different
+            SqueezeAction::Ignore, // different
+        ];
+
+        let mut line = 0;
+        let mut idx = 1;
+        for z in v.chunks(LSIZE) {
+            for i in z {
+                s.process(*i, idx);
+                idx += 1;
+            }
+            let action = s.action();
+            assert_eq!(action, exp[line]);
+            s.advance();
+            line += 1;
+        }
+    }
+
+    #[test]
+    /// first two lines same, hence squeeze symbol, third line diff, hence
+    /// print
+    fn one_squeeze_no_delete() {
+        const LINES: usize = 3;
+        let mut v = vec![0u8; (LINES - 1) * LSIZE];
+        v.extend(vec![1u8; 16]);
+
+        let mut s = Squeezer::new(true);
+        // just initialized
+        assert_eq!(s.action(), SqueezeAction::Ignore);
+        s.advance();
+
+        let exp = vec![
+            SqueezeAction::Ignore, // first line, print as is
+            SqueezeAction::Print,  // print squeeze symbol
+            SqueezeAction::Ignore, // different lines, print again
+        ];
+
+        let mut line = 0;
+        let mut idx = 1;
+        for z in v.chunks(LSIZE) {
+            for i in z {
+                s.process(*i, idx);
+                idx += 1;
+            }
+            let action = s.action();
+            s.advance();
+            assert_eq!(action, exp[line]);
+            line += 1;
+        }
+    }
+
+    #[test]
+    /// First line all eq, 2nd half eq with first line, then change
+    fn second_line_different() {
+        const LINES: usize = 2;
+        let mut v = vec![0u8; (LINES - 1) * LSIZE];
+        v.extend(vec![0u8; 8]);
+        v.extend(vec![1u8; 8]);
+
+        let mut s = Squeezer::new(true);
+        // just initialized
+        assert_eq!(s.action(), SqueezeAction::Ignore);
+        s.advance();
+
+        let exp = vec![
+            SqueezeAction::Ignore, // first line, print as is
+            SqueezeAction::Ignore, // print squeeze symbol
+        ];
+
+        let mut line = 0;
+        let mut idx = 1;
+        for z in v.chunks(LSIZE) {
+            for i in z {
+                s.process(*i, idx);
+                idx += 1;
+            }
+            let action = s.action();
+            s.advance();
+            assert_eq!(action, exp[line]);
+            line += 1;
+        }
+    }
+
+    #[test]
+    /// all three lines never become squeeze candidate (diff within line)
+    fn never_squeeze_candidate() {
+        let mut v = vec![];
+        v.extend(vec![0u8; 8]);
+        v.extend(vec![1u8; 8]);
+        v.extend(vec![0u8; 8]);
+        v.extend(vec![1u8; 8]);
+        v.extend(vec![0u8; 8]);
+        v.extend(vec![1u8; 8]);
+
+        let mut s = Squeezer::new(true);
+        // just initialized
+        assert_eq!(s.action(), SqueezeAction::Ignore);
+        s.advance();
+
+        let exp = vec![
+            SqueezeAction::Ignore, // first line, print as is
+            SqueezeAction::Ignore, // print squeeze symbol
+            SqueezeAction::Ignore, // print squeeze symbol
+        ];
+
+        let mut line = 0;
+        let mut idx = 1;
+        for z in v.chunks(LSIZE) {
+            for i in z {
+                s.process(*i, idx);
+                idx += 1;
+            }
+            let action = s.action();
+            s.advance();
+            assert_eq!(action, exp[line]);
+            line += 1;
+        }
+    }
+
+    #[test]
+    fn mix_everything() {
+        let mut v = vec![];
+        v.extend(vec![10u8; 16]); // print
+        v.extend(vec![20u8; 16]); // print
+        v.extend(vec![0u8; 16]); // print
+        v.extend(vec![0u8; 16]); // *
+        v.extend(vec![10u8; 16]); // print
+        v.extend(vec![20u8; 16]); // print
+        v.extend(vec![0u8; 16]); // print
+        v.extend(vec![0u8; 16]); // *
+        v.extend(vec![0u8; 16]); // delete
+        v.extend(vec![0u8; 16]); // delete*
+        v.extend(vec![20u8; 16]); // print
+        v.extend(vec![0u8; 12]); // print, only 12 bytes
+
+        let mut s = Squeezer::new(true);
+        // just initialized
+        assert_eq!(s.action(), SqueezeAction::Ignore);
+        s.advance();
+
+        let exp = vec![
+            SqueezeAction::Ignore,
+            SqueezeAction::Ignore,
+            SqueezeAction::Ignore,
+            SqueezeAction::Print,
+            SqueezeAction::Ignore,
+            SqueezeAction::Ignore,
+            SqueezeAction::Ignore,
+            SqueezeAction::Print,
+            SqueezeAction::Delete,
+            SqueezeAction::Delete,
+            SqueezeAction::Ignore,
+            SqueezeAction::Ignore,
+        ];
+
+        let mut line = 0;
+        let mut idx = 1;
+        for z in v.chunks(LSIZE) {
+            for i in z {
+                s.process(*i, idx);
+                idx += 1;
+            }
+            let action = s.action();
+            s.advance();
+            assert_eq!(action, exp[line]);
+            line += 1;
+        }
+    }
+
+    #[test]
+    fn last_char_diff() {
+        // see issue #62
+        let mut v = vec![];
+        v.extend(vec![20u8; 16]);
+        v.extend(vec![20u8; 15]);
+        v.push(61);
+        v.extend(vec![20u8; 16]);
+        v.extend(vec![20u8; 16]);
+
+        let mut s = Squeezer::new(true);
+        // just initialized
+        assert_eq!(s.action(), SqueezeAction::Ignore);
+        s.advance();
+
+        let exp = vec![
+            SqueezeAction::Ignore, // print as is
+            SqueezeAction::Ignore, // print as is
+            SqueezeAction::Ignore, // print as is
+            SqueezeAction::Print,  // print '*' char
+        ];
+
+        let mut line = 0;
+        let mut idx = 1;
+        for z in v.chunks(LSIZE) {
+            for i in z {
+                s.process(*i, idx);
+                idx += 1;
+            }
+            assert_eq!(s.action(), exp[line]);
+            s.advance();
+            line += 1;
+        }
+    }
+
+    #[test]
+    fn first_char_diff() {
+        // see issue #62
+        let mut v = vec![];
+        v.extend(vec![20u8; 16]);
+        v.push(61);
+        v.extend(vec![20u8; 15]);
+        v.extend(vec![20u8; 16]);
+
+        let mut s = Squeezer::new(true);
+        // just initialized
+        assert_eq!(s.action(), SqueezeAction::Ignore);
+        s.advance();
+
+        let exp = vec![
+            SqueezeAction::Ignore, // print as is
+            SqueezeAction::Ignore, // print as is
+            SqueezeAction::Ignore, // print as is
+        ];
+
+        let mut line = 0;
+        let mut idx = 1;
+        for z in v.chunks(LSIZE) {
+            for i in z {
+                s.process(*i, idx);
+                idx += 1;
+            }
+            assert_eq!(s.action(), exp[line]);
+            s.advance();
+            line += 1;
+        }
+    }
+}