Updates for 0.13

This changes the meaning of `-C` to "show the character panel". The long
version `--no-characters` can still be used to hide the character panel.

closes #187

.github/workflows/CICD.yml

@@ -1,8 +1,8 @@
 name: CICD
 
 env:
-  MIN_SUPPORTED_RUST_VERSION: "1.60.0"
   CICD_INTERMEDIATES_DIR: "_cicd-intermediates"
+  MSRV_FEATURES: ""
 
 on:
   workflow_dispatch:
@@ -14,84 +14,102 @@ on:
       - '*'
 
 jobs:
+  crate_metadata:
+    name: Extract crate metadata
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v3
+    - name: Extract crate information
+      id: crate_metadata
+      run: |
+        cargo metadata --no-deps --format-version 1 | jq -r '"name=" + .packages[0].name' | tee -a $GITHUB_OUTPUT
+        cargo metadata --no-deps --format-version 1 | jq -r '"version=" + .packages[0].version' | tee -a $GITHUB_OUTPUT
+        cargo metadata --no-deps --format-version 1 | jq -r '"maintainer=" + .packages[0].authors[0]' | tee -a $GITHUB_OUTPUT
+        cargo metadata --no-deps --format-version 1 | jq -r '"homepage=" + .packages[0].homepage' | tee -a $GITHUB_OUTPUT
+        cargo metadata --no-deps --format-version 1 | jq -r '"msrv=" + .packages[0].rust_version' | tee -a $GITHUB_OUTPUT
+    outputs:
+      name: ${{ steps.crate_metadata.outputs.name }}
+      version: ${{ steps.crate_metadata.outputs.version }}
+      maintainer: ${{ steps.crate_metadata.outputs.maintainer }}
+      homepage: ${{ steps.crate_metadata.outputs.homepage }}
+      msrv: ${{ steps.crate_metadata.outputs.msrv }}
+
+  ensure_cargo_fmt:
+    name: Ensure 'cargo fmt' has been run
+    runs-on: ubuntu-20.04
+    steps:
+    - uses: dtolnay/rust-toolchain@stable
+      with:
+        components: rustfmt
+    - uses: actions/checkout@v3
+    - run: cargo fmt -- --check
+
   min_version:
     name: Minimum supported rust version
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-20.04
+    needs: crate_metadata
     steps:
     - name: Checkout source code
-      uses: actions/checkout@v2
+      uses: actions/checkout@v3
 
-    - name: Install rust toolchain (v${{ env.MIN_SUPPORTED_RUST_VERSION }})
-      uses: actions-rs/toolchain@v1
+    - name: Install rust toolchain (v${{ needs.crate_metadata.outputs.msrv }})
+      uses: dtolnay/rust-toolchain@master
       with:
-        toolchain: ${{ env.MIN_SUPPORTED_RUST_VERSION }}
-        default: true
-        profile: minimal # minimal component installation (ie, no documentation)
-        components: clippy, rustfmt
-
-    - name: Ensure `cargo fmt` has been run
-      uses: actions-rs/cargo@v1
-      with:
-        command: fmt
-        args: -- --check
-
+        toolchain: ${{ needs.crate_metadata.outputs.msrv }}
+        components: clippy
     - name: Run clippy (on minimum supported rust version to prevent warnings we can't fix)
-      uses: actions-rs/cargo@v1
-      with:
-        command: clippy
-        args: --locked --all-targets
-
+      run: cargo clippy --locked --all-targets ${{ env.MSRV_FEATURES }}
     - name: Run tests
-      uses: actions-rs/cargo@v1
-      with:
-        command: test
-        args: --locked
+      run: cargo test --locked ${{ env.MSRV_FEATURES }}
 
   build:
-    name: ${{ matrix.job.os }} (${{ matrix.job.target }})
+    name: ${{ matrix.job.target }} (${{ matrix.job.os }})
     runs-on: ${{ matrix.job.os }}
+    needs: crate_metadata
     strategy:
       fail-fast: false
       matrix:
         job:
-          - { os: ubuntu-18.04, target: arm-unknown-linux-gnueabihf , use-cross: true }
-          - { os: ubuntu-18.04, target: aarch64-unknown-linux-gnu   , use-cross: true }
-          - { os: ubuntu-18.04, target: i686-unknown-linux-gnu      , use-cross: true }
-          - { os: ubuntu-18.04, target: i686-unknown-linux-musl     , use-cross: true }
-          - { os: ubuntu-18.04, target: x86_64-unknown-linux-gnu    }
-          - { os: ubuntu-18.04, target: x86_64-unknown-linux-musl   , use-cross: true }
-          - { os: macos-10.15 , target: x86_64-apple-darwin         }
-          # - { os: windows-2019, target: i686-pc-windows-gnu         }  ## disabled; error: linker `i686-w64-mingw32-gcc` not found
-          - { os: windows-2019, target: i686-pc-windows-msvc        }
-          - { os: windows-2019, target: x86_64-pc-windows-gnu       }
-          - { os: windows-2019, target: x86_64-pc-windows-msvc      }
+          - { target: aarch64-unknown-linux-gnu   , os: ubuntu-20.04, use-cross: true }
+          - { target: arm-unknown-linux-gnueabihf , os: ubuntu-20.04, use-cross: true }
+          - { target: arm-unknown-linux-musleabihf, os: ubuntu-20.04, use-cross: true }
+          - { target: i686-pc-windows-msvc        , os: windows-2019                  }
+          - { target: i686-unknown-linux-gnu      , os: ubuntu-20.04, use-cross: true }
+          - { target: i686-unknown-linux-musl     , os: ubuntu-20.04, use-cross: true }
+          - { target: x86_64-apple-darwin         , os: macos-12                      }
+          - { target: x86_64-pc-windows-gnu       , os: windows-2019                  }
+          - { target: x86_64-pc-windows-msvc      , os: windows-2019                  }
+          - { target: x86_64-unknown-linux-gnu    , os: ubuntu-20.04, use-cross: true }
+          - { target: x86_64-unknown-linux-musl   , os: ubuntu-20.04, use-cross: true }
+    env:
+      BUILD_CMD: cargo
     steps:
     - name: Checkout source code
-      uses: actions/checkout@v2
+      uses: actions/checkout@v3
 
     - name: Install prerequisites
       shell: bash
       run: |
         case ${{ matrix.job.target }} in
-          arm-unknown-linux-gnueabihf) sudo apt-get -y update ; sudo apt-get -y install gcc-arm-linux-gnueabihf ;;
+          arm-unknown-linux-*) sudo apt-get -y update ; sudo apt-get -y install gcc-arm-linux-gnueabihf ;;
           aarch64-unknown-linux-gnu) sudo apt-get -y update ; sudo apt-get -y install gcc-aarch64-linux-gnu ;;
         esac
 
-    - name: Extract crate information
-      shell: bash
-      run: |
-        echo "PROJECT_NAME=$(sed -n 's/^name = "\(.*\)"/\1/p' Cargo.toml | head -n1)" >> $GITHUB_ENV
-        echo "PROJECT_VERSION=$(sed -n 's/^version = "\(.*\)"/\1/p' Cargo.toml | head -n1)" >> $GITHUB_ENV
-        echo "PROJECT_MAINTAINER=$(sed -n 's/^authors = \["\(.*\)"\]/\1/p' Cargo.toml)" >> $GITHUB_ENV
-        echo "PROJECT_HOMEPAGE=$(sed -n 's/^homepage = "\(.*\)"/\1/p' Cargo.toml)" >> $GITHUB_ENV
-
     - name: Install Rust toolchain
-      uses: actions-rs/toolchain@v1
+      uses: dtolnay/rust-toolchain@stable
       with:
-        toolchain: stable
-        target: ${{ matrix.job.target }}
-        override: true
-        profile: minimal # minimal component installation (ie, no documentation)
+        targets: ${{ matrix.job.target }}
+
+    - name: Install cross
+      if: matrix.job.use-cross
+      uses: taiki-e/install-action@v2
+      with:
+        tool: cross
+
+    - name: Overwrite build command env variable
+      if: matrix.job.use-cross
+      shell: bash
+      run: echo "BUILD_CMD=cross" >> $GITHUB_ENV
 
     - name: Show version information (Rust, cargo, GCC)
       shell: bash
@@ -104,21 +122,16 @@ jobs:
         rustc -V
 
     - name: Build
-      uses: actions-rs/cargo@v1
-      with:
-        use-cross: ${{ matrix.job.use-cross }}
-        command: build
-        args: --release --target=${{ matrix.job.target }}
+      shell: bash
+      run: $BUILD_CMD build --locked --release --target=${{ matrix.job.target }}
 
     - name: Run example
-      uses: actions-rs/cargo@v1
-      with:
-        use-cross: ${{ matrix.job.use-cross }}
-        command: run
-        args: --release --target=${{ matrix.job.target }} --example=simple
+      if: ${{ !matrix.job.use-cross }}
+      shell: bash
+      run: $BUILD_CMD run --release --target=${{ matrix.job.target }} --example=simple
 
-    - name: Strip debug information from executable
-      id: strip
+    - name: Set binary name & path
+      id: bin
       shell: bash
       run: |
         # Figure out suffix of binary
@@ -127,31 +140,13 @@ jobs:
           *-pc-windows-*) EXE_suffix=".exe" ;;
         esac;
 
-        # Figure out what strip tool to use if any
-        STRIP="strip"
-        case ${{ matrix.job.target }} in
-          arm-unknown-linux-gnueabihf) STRIP="arm-linux-gnueabihf-strip" ;;
-          aarch64-unknown-linux-gnu) STRIP="aarch64-linux-gnu-strip" ;;
-          *-pc-windows-msvc) STRIP="" ;;
-        esac;
-
         # Setup paths
-        BIN_DIR="${{ env.CICD_INTERMEDIATES_DIR }}/stripped-release-bin/"
-        mkdir -p "${BIN_DIR}"
-        BIN_NAME="${{ env.PROJECT_NAME }}${EXE_suffix}"
-        BIN_PATH="${BIN_DIR}/${BIN_NAME}"
+        BIN_NAME="${{ needs.crate_metadata.outputs.name }}${EXE_suffix}"
+        BIN_PATH="target/${{ matrix.job.target }}/release/${BIN_NAME}"
 
-        # Copy the release build binary to the result location
-        cp "target/${{ matrix.job.target }}/release/${BIN_NAME}" "${BIN_DIR}"
-
-        # Also strip if possible
-        if [ -n "${STRIP}" ]; then
-          "${STRIP}" "${BIN_PATH}"
-        fi
-
-        # Let subsequent steps know where to find the (stripped) bin
-        echo ::set-output name=BIN_PATH::${BIN_PATH}
-        echo ::set-output name=BIN_NAME::${BIN_NAME}
+        # Let subsequent steps know where to find the binary
+        echo "BIN_PATH=${BIN_PATH}" >> $GITHUB_OUTPUT
+        echo "BIN_NAME=${BIN_NAME}" >> $GITHUB_OUTPUT
 
     - name: Set testing options
       id: test-options
@@ -159,44 +154,41 @@ jobs:
       run: |
         # test only library unit tests and binary for arm-type targets
         unset CARGO_TEST_OPTIONS
-        unset CARGO_TEST_OPTIONS ; case ${{ matrix.job.target }} in arm-* | aarch64-*) CARGO_TEST_OPTIONS="--lib --bin ${PROJECT_NAME}" ;; esac;
-        echo ::set-output name=CARGO_TEST_OPTIONS::${CARGO_TEST_OPTIONS}
+        unset CARGO_TEST_OPTIONS ; case ${{ matrix.job.target }} in arm-* | aarch64-*) CARGO_TEST_OPTIONS="--lib --bin ${{ needs.crate_metadata.outputs.name }}" ;; esac;
+        echo "CARGO_TEST_OPTIONS=${CARGO_TEST_OPTIONS}" >> $GITHUB_OUTPUT
 
     - name: Run tests
-      uses: actions-rs/cargo@v1
-      with:
-        use-cross: ${{ matrix.job.use-cross }}
-        command: test
-        args: --target=${{ matrix.job.target }} ${{ steps.test-options.outputs.CARGO_TEST_OPTIONS}}
+      shell: bash
+      run: $BUILD_CMD test --locked --target=${{ matrix.job.target }} ${{ steps.test-options.outputs.CARGO_TEST_OPTIONS}}
 
     - name: Setup Pandoc
       uses: r-lib/actions/setup-pandoc@v2
 
     - name: Generate man page
-      run: pandoc -s -f markdown -t man -o "doc/${{ env.PROJECT_NAME }}.1" "doc/${{ env.PROJECT_NAME }}.1.md"
+      run: pandoc -s -f markdown -t man -o "doc/${{ needs.crate_metadata.outputs.name }}.1" "doc/${{ needs.crate_metadata.outputs.name }}.1.md"
 
     - name: Create tarball
       id: package
       shell: bash
       run: |
         PKG_suffix=".tar.gz" ; case ${{ matrix.job.target }} in *-pc-windows-*) PKG_suffix=".zip" ;; esac;
-        PKG_BASENAME=${PROJECT_NAME}-v${PROJECT_VERSION}-${{ matrix.job.target }}
+        PKG_BASENAME=${{ needs.crate_metadata.outputs.name }}-v${{ needs.crate_metadata.outputs.version }}-${{ matrix.job.target }}
         PKG_NAME=${PKG_BASENAME}${PKG_suffix}
-        echo ::set-output name=PKG_NAME::${PKG_NAME}
+        echo "PKG_NAME=${PKG_NAME}" >> $GITHUB_OUTPUT
 
         PKG_STAGING="${{ env.CICD_INTERMEDIATES_DIR }}/package"
         ARCHIVE_DIR="${PKG_STAGING}/${PKG_BASENAME}/"
         mkdir -p "${ARCHIVE_DIR}"
 
         # Binary
-        cp "${{ steps.strip.outputs.BIN_PATH }}" "$ARCHIVE_DIR"
-
-        # Man page
-        cp "doc/${{ env.PROJECT_NAME }}.1" "$ARCHIVE_DIR"
+        cp "${{ steps.bin.outputs.BIN_PATH }}" "$ARCHIVE_DIR"
 
         # README, LICENSE and CHANGELOG files
         cp "README.md" "LICENSE-MIT" "LICENSE-APACHE" "CHANGELOG.md" "$ARCHIVE_DIR"
 
+        # Man page
+        cp "doc/${{ needs.crate_metadata.outputs.name }}.1" "$ARCHIVE_DIR"
+
         # base compressed package
         pushd "${PKG_STAGING}/" >/dev/null
         case ${{ matrix.job.target }} in
@@ -206,7 +198,7 @@ jobs:
         popd >/dev/null
 
         # Let subsequent steps know where to find the compressed package
-        echo ::set-output name=PKG_PATH::"${PKG_STAGING}/${PKG_NAME}"
+        echo "PKG_PATH=${PKG_STAGING}/${PKG_NAME}" >> $GITHUB_OUTPUT
 
     - name: Create Debian package
       id: debian-package
@@ -218,10 +210,10 @@ jobs:
         DPKG_DIR="${DPKG_STAGING}/dpkg"
         mkdir -p "${DPKG_DIR}"
 
-        DPKG_BASENAME=${PROJECT_NAME}
-        DPKG_CONFLICTS=${PROJECT_NAME}-musl
-        case ${{ matrix.job.target }} in *-musl) DPKG_BASENAME=${PROJECT_NAME}-musl ; DPKG_CONFLICTS=${PROJECT_NAME} ;; esac;
-        DPKG_VERSION=${PROJECT_VERSION}
+        DPKG_BASENAME=${{ needs.crate_metadata.outputs.name }}
+        DPKG_CONFLICTS=${{ needs.crate_metadata.outputs.name }}-musl
+        case ${{ matrix.job.target }} in *-musl) DPKG_BASENAME=${{ needs.crate_metadata.outputs.name }}-musl ; DPKG_CONFLICTS=${{ needs.crate_metadata.outputs.name }} ;; esac;
+        DPKG_VERSION=${{ needs.crate_metadata.outputs.version }}
 
         unset DPKG_ARCH
         case ${{ matrix.job.target }} in
@@ -233,14 +225,14 @@ jobs:
         esac;
 
         DPKG_NAME="${DPKG_BASENAME}_${DPKG_VERSION}_${DPKG_ARCH}.deb"
-        echo ::set-output name=DPKG_NAME::${DPKG_NAME}
+        echo "DPKG_NAME=${DPKG_NAME}" >> $GITHUB_OUTPUT
 
         # Binary
-        install -Dm755 "${{ steps.strip.outputs.BIN_PATH }}" "${DPKG_DIR}/usr/bin/${{ steps.strip.outputs.BIN_NAME }}"
+        install -Dm755 "${{ steps.bin.outputs.BIN_PATH }}" "${DPKG_DIR}/usr/bin/${{ steps.bin.outputs.BIN_NAME }}"
 
         # Man page
-        install -Dm644 "doc/${{ env.PROJECT_NAME }}.1" "${DPKG_DIR}/usr/share/man/man1/${{ env.PROJECT_NAME }}.1"
-        gzip -n --best "${DPKG_DIR}/usr/share/man/man1/${{ env.PROJECT_NAME }}.1"
+        install -Dm644 'doc/${{ needs.crate_metadata.outputs.name }}.1' "${DPKG_DIR}/usr/share/man/man1/${{ needs.crate_metadata.outputs.name }}.1"
+        gzip -n --best "${DPKG_DIR}/usr/share/man/man1/${{ needs.crate_metadata.outputs.name }}.1"
 
         # README and LICENSE
         install -Dm644 "README.md" "${DPKG_DIR}/usr/share/doc/${DPKG_BASENAME}/README.md"
@@ -251,12 +243,12 @@ jobs:
 
         cat > "${DPKG_DIR}/usr/share/doc/${DPKG_BASENAME}/copyright" <<EOF
         Format: http://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
-        Upstream-Name: ${{ env.PROJECT_NAME }}
-        Source: ${{ env.PROJECT_HOMEPAGE }}
+        Upstream-Name: ${{ needs.crate_metadata.outputs.name }}
+        Source: ${{ needs.crate_metadata.outputs.homepage }}
 
         Files: *
-        Copyright: ${{ env.PROJECT_MAINTAINER }}
-        Copyright: $COPYRIGHT_YEARS ${{ env.PROJECT_MAINTAINER }}
+        Copyright: ${{ needs.crate_metadata.outputs.maintainer }}
+        Copyright: $COPYRIGHT_YEARS ${{ needs.crate_metadata.outputs.maintainer }}
         License: Apache-2.0 or MIT
 
         License: Apache-2.0
@@ -297,16 +289,16 @@ jobs:
         Version: ${DPKG_VERSION}
         Section: utils
         Priority: optional
-        Maintainer: ${{ env.PROJECT_MAINTAINER }}
-        Homepage: ${{ env.PROJECT_HOMEPAGE }}
+        Maintainer: ${{ needs.crate_metadata.outputs.maintainer }}
+        Homepage: ${{ needs.crate_metadata.outputs.homepage }}
         Architecture: ${DPKG_ARCH}
-        Provides: ${{ env.PROJECT_NAME }}
+        Provides: ${{ needs.crate_metadata.outputs.name }}
         Conflicts: ${DPKG_CONFLICTS}
-        Description: colorized hex viewer for the terminal.
+        Description: A command-line benchmarking tool
         EOF
 
         DPKG_PATH="${DPKG_STAGING}/${DPKG_NAME}"
-        echo ::set-output name=DPKG_PATH::${DPKG_PATH}
+        echo "DPKG_PATH=${DPKG_PATH}" >> $GITHUB_OUTPUT
 
         # build dpkg
         fakeroot dpkg-deb --build "${DPKG_DIR}" "${DPKG_PATH}"
@@ -329,7 +321,7 @@ jobs:
       shell: bash
       run: |
         unset IS_RELEASE ; if [[ $GITHUB_REF =~ ^refs/tags/v[0-9].* ]]; then IS_RELEASE='true' ; fi
-        echo ::set-output name=IS_RELEASE::${IS_RELEASE}
+        echo "IS_RELEASE=${IS_RELEASE}" >> $GITHUB_OUTPUT
 
     - name: Publish archives and packages
       uses: softprops/action-gh-release@v1

CHANGELOG.md

@@ -1,3 +1,18 @@
+# v0.13.0
+
+## Features
+
+- Support both little and big Endian dumps using `--endianness={little,big}`, see #189 and #104 (@RinHizakura)
+
+## Changes
+
+- **Breaking**: Changed the meaning of the short flag `-C` to be consistent with `hexdump -C`. Previously, this would *hide* the character panel, but now `-C` *shows* the character panel, in case it has been previously (e.g. in an `alias`) disabled with `--no-characters`, see #187 (@sharkdp)
+
+## `hexyl` as a library
+
+- New `endianness` method for `PrinterBuilder`
+
+
 # v0.12.0
 
 ## Features

Cargo.lock

@@ -200,7 +200,7 @@ dependencies = [
 
 [[package]]
 name = "hexyl"
-version = "0.12.0"
+version = "0.13.0"
 dependencies = [
  "anyhow",
  "assert_cmd",

Cargo.toml

@@ -7,8 +7,9 @@ license = "MIT/Apache-2.0"
 name = "hexyl"
 readme = "README.md"
 repository = "https://github.com/sharkdp/hexyl"
-version = "0.12.0"
+version = "0.13.0"
 edition = "2021"
+rust-version = "1.60"
 
 [dependencies]
 anyhow = "1.0"

src/bin/hexyl.rs

@@ -17,7 +17,7 @@ use thiserror::Error as ThisError;
 
 use terminal_size::terminal_size;
 
-use hexyl::{Base, BorderStyle, Input, PrinterBuilder};
+use hexyl::{Base, BorderStyle, Endianness, Input, PrinterBuilder};
 
 const DEFAULT_BLOCK_SIZE: i64 = 512;
 
@@ -128,10 +128,17 @@ fn run() -> Result<()> {
         ))
         .arg(
             Arg::new("no_chars")
-                .short('C')
                 .long("no-characters")
                 .action(ArgAction::SetFalse)
-                .help("Whether to display the character panel on the right."),
+                .help("Do not show the character panel on the right."),
+        )
+        .arg(
+            Arg::new("chars")
+                .short('C')
+                .long("characters")
+                .overrides_with("no_chars")
+                .action(ArgAction::SetTrue)
+                .help("Show the character panel on the right. This is the default, unless --no-characters has been specified."),
         )
         .arg(
             Arg::new("no_position")
@@ -174,10 +181,34 @@ fn run() -> Result<()> {
                 .value_name("N")
                 .help(
                     "Number of bytes/octets that should be grouped together. \
-                    Possible group sizes are 1, 2, 4, 8. The default is 1. \
-                    '--groupsize can be used as an alias (xxd-compatibility).",
+                    Possible group sizes are 1, 2, 4, 8. The default is 1. You \
+                    can use the '--endianness' option to control the ordering of \
+                    the bytes within a group. '--groupsize' can be used as an \
+                    alias (xxd-compatibility).",
                 ),
         )
+        .arg(
+            Arg::new("endianness")
+                .long("endianness")
+                .num_args(1)
+                .value_name("FORMAT")
+                .value_parser(["big", "little"])
+                .default_value("big")
+                .help(
+                    "Whether to print out groups in little-endian or big-endian \
+                     format. This option only has an effect if the '--group-size' \
+                     is larger than 1. '-e' can be used as an alias for \
+                     '--endianness=little'.",
+                ),
+        )
+        .arg(
+            Arg::new("little_endian_format")
+                .short('e')
+                .action(ArgAction::SetTrue)
+                .overrides_with("endianness")
+                .hide(true)
+                .help("An alias for '--endianness=little'."),
+        )
         .arg(
             Arg::new("base")
                 .short('b')
@@ -425,6 +456,16 @@ fn run() -> Result<()> {
         )
     };
 
+    let little_endian_format = *matches.get_one::<bool>("little_endian_format").unwrap();
+    let endianness = matches.get_one::<String>("endianness");
+    let endianness = match (
+        endianness.map(|s| s.as_ref()).unwrap(),
+        little_endian_format,
+    ) {
+        (_, true) | ("little", _) => Endianness::Little,
+        ("big", _) => Endianness::Big,
+        _ => unreachable!(),
+    };
     let stdout = io::stdout();
     let mut stdout_lock = BufWriter::new(stdout.lock());
 
@@ -437,6 +478,7 @@ fn run() -> Result<()> {
         .num_panels(panels)
         .group_size(group_size)
         .with_base(base)
+        .endianness(endianness)
         .build();
     printer.display_offset(skip_offset + display_offset);
     printer.print_all(&mut reader).map_err(|e| anyhow!(e))?;

src/lib.rs

@@ -21,6 +21,7 @@ const COLOR_ASCII_OTHER: &[u8] = colors::Green::ANSI_FG.as_bytes();
 const COLOR_NONASCII: &[u8] = colors::Yellow::ANSI_FG.as_bytes();
 const COLOR_RESET: &[u8] = colors::Default::ANSI_FG.as_bytes();
 
+#[derive(Copy, Clone)]
 pub enum ByteCategory {
     Null,
     AsciiPrintable,
@@ -29,6 +30,12 @@ pub enum ByteCategory {
     NonAscii,
 }
 
+#[derive(Copy, Clone)]
+pub enum Endianness {
+    Little,
+    Big,
+}
+
 #[derive(PartialEq)]
 enum Squeezer {
     Print,
@@ -159,6 +166,7 @@ pub struct PrinterBuilder<'a, Writer: Write> {
     panels: u64,
     group_size: u8,
     base: Base,
+    endianness: Endianness,
 }
 
 impl<'a, Writer: Write> PrinterBuilder<'a, Writer> {
@@ -173,6 +181,7 @@ impl<'a, Writer: Write> PrinterBuilder<'a, Writer> {
             panels: 2,
             group_size: 1,
             base: Base::Hexadecimal,
+            endianness: Endianness::Big,
         }
     }
 
@@ -216,6 +225,11 @@ impl<'a, Writer: Write> PrinterBuilder<'a, Writer> {
         self
     }
 
+    pub fn endianness(mut self, endianness: Endianness) -> Self {
+        self.endianness = endianness;
+        self
+    }
+
     pub fn build(self) -> Printer<'a, Writer> {
         Printer::new(
             self.writer,
@@ -227,6 +241,7 @@ impl<'a, Writer: Write> PrinterBuilder<'a, Writer> {
             self.panels,
             self.group_size,
             self.base,
+            self.endianness,
         )
     }
 }
@@ -254,6 +269,8 @@ pub struct Printer<'a, Writer: Write> {
     group_size: u8,
     /// The number of digits used to write the base.
     base_digits: u8,
+    /// Whether to show groups in little or big endian format.
+    endianness: Endianness,
 }
 
 impl<'a, Writer: Write> Printer<'a, Writer> {
@@ -267,6 +284,7 @@ impl<'a, Writer: Write> Printer<'a, Writer> {
         panels: u64,
         group_size: u8,
         base: Base,
+        endianness: Endianness,
     ) -> Printer<'a, Writer> {
         Printer {
             idx: 0,
@@ -304,6 +322,7 @@ impl<'a, Writer: Write> Printer<'a, Writer> {
                 Base::Decimal => 3,
                 Base::Hexadecimal => 2,
             },
+            endianness,
         }
     }
 
@@ -523,8 +542,26 @@ impl<'a, Writer: Write> Printer<'a, Writer> {
         Ok(())
     }
 
+    fn reorder_buffer_to_little_endian(&self, buf: &mut Vec<u8>) {
+        let n = buf.len();
+        let group_sz = self.group_size as usize;
+
+        for idx in (0..n).step_by(group_sz) {
+            let remaining = n - idx;
+            let total = remaining.min(group_sz);
+
+            buf[idx..idx + total].reverse();
+        }
+    }
+
     pub fn print_bytes(&mut self) -> io::Result<()> {
-        for (i, &b) in self.line_buf.clone().iter().enumerate() {
+        let mut buf = self.line_buf.clone();
+
+        if matches!(self.endianness, Endianness::Little) {
+            self.reorder_buffer_to_little_endian(&mut buf);
+        };
+
+        for (i, &b) in buf.iter().enumerate() {
             self.print_byte(i, b)?;
         }
         Ok(())
@@ -682,6 +719,7 @@ mod tests {
             2,
             1,
             Base::Hexadecimal,
+            Endianness::Big,
         );
 
         printer.print_all(input).unwrap();
@@ -736,6 +774,7 @@ mod tests {
             2,
             1,
             Base::Hexadecimal,
+            Endianness::Big,
         );
         printer.display_offset(0xdeadbeef);
 
@@ -769,6 +808,7 @@ mod tests {
             4,
             1,
             Base::Hexadecimal,
+            Endianness::Big,
         );
 
         printer.print_all(input).unwrap();
@@ -828,6 +868,7 @@ mod tests {
             3,
             1,
             Base::Hexadecimal,
+            Endianness::Big,
         );
 
         printer.print_all(input).unwrap();

tests/integration_tests.rs

@@ -292,12 +292,12 @@ mod display_settings {
     }
 }
 
-mod group {
+mod group_and_endianness {
     use super::hexyl;
     use super::PrettyAssert;
 
     #[test]
-    fn group_2_bytes() {
+    fn group_2_bytes_be() {
         hexyl()
             .arg("ascii")
             .arg("--color=never")
@@ -312,7 +312,23 @@ mod group {
     }
 
     #[test]
-    fn group_4_bytes() {
+    fn group_2_bytes_le() {
+        hexyl()
+            .arg("ascii")
+            .arg("--color=never")
+            .arg("--group-size=2")
+            .arg("--endianness=little")
+            .assert()
+            .success()
+            .stdout(
+                "┌────────┬─────────────────────┬─────────────────────┬────────┬────────┐\n\
+                 │00000000│ 3130 3332 3534 3736 ┊ 3938 6261 6463 0a65 │01234567┊89abcde_│\n\
+                 └────────┴─────────────────────┴─────────────────────┴────────┴────────┘\n",
+            );
+    }
+
+    #[test]
+    fn group_4_bytes_be() {
         hexyl()
             .arg("ascii")
             .arg("--color=never")
@@ -327,7 +343,23 @@ mod group {
     }
 
     #[test]
-    fn group_8_bytes() {
+    fn group_4_bytes_le() {
+        hexyl()
+            .arg("ascii")
+            .arg("--color=never")
+            .arg("--group-size=4")
+            .arg("--endianness=little")
+            .assert()
+            .success()
+            .stdout(
+                "┌────────┬───────────────────┬───────────────────┬────────┬────────┐\n\
+                 │00000000│ 33323130 37363534 ┊ 62613938 0a656463 │01234567┊89abcde_│\n\
+                 └────────┴───────────────────┴───────────────────┴────────┴────────┘\n",
+            );
+    }
+
+    #[test]
+    fn group_8_bytes_be() {
         hexyl()
             .arg("ascii")
             .arg("--color=never")
@@ -341,6 +373,22 @@ mod group {
             );
     }
 
+    #[test]
+    fn group_8_bytes_le() {
+        hexyl()
+            .arg("ascii")
+            .arg("--color=never")
+            .arg("--group-size=8")
+            .arg("--endianness=little")
+            .assert()
+            .success()
+            .stdout(
+                "┌────────┬──────────────────┬──────────────────┬────────┬────────┐\n\
+                 │00000000│ 3736353433323130 ┊ 0a65646362613938 │01234567┊89abcde_│\n\
+                 └────────┴──────────────────┴──────────────────┴────────┴────────┘\n",
+            );
+    }
+
     #[test]
     fn group_size_plain() {
         hexyl()