Bump MSRV

Set `.hidden(true)` option

This won't clutter the help text too much.

.github/workflows/CICD.yml

@@ -0,0 +1,315 @@
+name: CICD
+
+env:
+  MIN_SUPPORTED_RUST_VERSION: "1.40.0"
+  CICD_INTERMEDIATES_DIR: "_cicd-intermediates"
+
+on:
+  workflow_dispatch:
+  pull_request:
+  push:
+    branches:
+      - master
+    tags:
+      - '*'
+
+jobs:
+  min_version:
+    name: Minimum supported rust version
+    runs-on: ubuntu-18.04
+    steps:
+    - name: Checkout source code
+      uses: actions/checkout@v2
+
+    - name: Install rust toolchain (v${{ env.MIN_SUPPORTED_RUST_VERSION }})
+      uses: actions-rs/toolchain@v1
+      with:
+        toolchain: ${{ env.MIN_SUPPORTED_RUST_VERSION }}
+        default: true
+        profile: minimal # minimal component installation (ie, no documentation)
+
+    - name: Run tests
+      uses: actions-rs/cargo@v1
+      with:
+        command: test
+
+  build:
+    name: ${{ matrix.job.os }} (${{ matrix.job.target }})
+    runs-on: ${{ matrix.job.os }}
+    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      }
+    steps:
+    - name: Checkout source code
+      uses: actions/checkout@v2
+
+    - name: Install prerequisites
+      shell: bash
+      run: |
+        case ${{ matrix.job.target }} in
+          arm-unknown-linux-gnueabihf) sudo apt-get -y update ; sudo apt-get -y install gcc-arm-linux-gnueabihf ;;
+          aarch64-unknown-linux-gnu) sudo apt-get -y update ; sudo apt-get -y install gcc-aarch64-linux-gnu ;;
+        esac
+
+    - name: Extract crate information
+      shell: bash
+      run: |
+        echo "PROJECT_NAME=$(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
+      with:
+        toolchain: stable
+        target: ${{ matrix.job.target }}
+        override: true
+        profile: minimal # minimal component installation (ie, no documentation)
+
+    - name: Show version information (Rust, cargo, GCC)
+      shell: bash
+      run: |
+        gcc --version || true
+        rustup -V
+        rustup toolchain list
+        rustup default
+        cargo -V
+        rustc -V
+
+    - name: Build
+      uses: actions-rs/cargo@v1
+      with:
+        use-cross: ${{ matrix.job.use-cross }}
+        command: build
+        args: --release --target=${{ 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
+
+    - name: Strip debug information from executable
+      id: strip
+      shell: bash
+      run: |
+        # Figure out suffix of binary
+        EXE_suffix=""
+        case ${{ matrix.job.target }} in
+          *-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}/${BIN_NAME}"
+
+        # Copy the release build binary to the result location
+        cp "target/${{ 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}
+
+    - name: Set testing options
+      id: test-options
+      shell: bash
+      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}
+
+    - 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}}
+
+    - 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_NAME=${PKG_BASENAME}${PKG_suffix}
+        echo ::set-output name=PKG_NAME::${PKG_NAME}
+
+        PKG_STAGING="${{ env.CICD_INTERMEDIATES_DIR }}/package"
+        ARCHIVE_DIR="${PKG_STAGING}/${PKG_BASENAME}/"
+        mkdir -p "${ARCHIVE_DIR}"
+
+        # Binary
+        cp "${{ steps.strip.outputs.BIN_PATH }}" "$ARCHIVE_DIR"
+
+        # README, LICENSE and CHANGELOG files
+        cp "README.md" "LICENSE-MIT" "LICENSE-APACHE" "CHANGELOG.md" "$ARCHIVE_DIR"
+
+        # base compressed package
+        pushd "${PKG_STAGING}/" >/dev/null
+        case ${{ matrix.job.target }} in
+          *-pc-windows-*) 7z -y a "${PKG_NAME}" "${PKG_BASENAME}"/* | tail -2 ;;
+          *) tar czf "${PKG_NAME}" "${PKG_BASENAME}"/* ;;
+        esac;
+        popd >/dev/null
+
+        # Let subsequent steps know where to find the compressed package
+        echo ::set-output name=PKG_PATH::"${PKG_STAGING}/${PKG_NAME}"
+
+    - name: Create Debian package
+      id: debian-package
+      shell: bash
+      if: startsWith(matrix.job.os, 'ubuntu')
+      run: |
+        COPYRIGHT_YEARS="2018 - "$(date "+%Y")
+        DPKG_STAGING="${{ env.CICD_INTERMEDIATES_DIR }}/debian-package"
+        DPKG_DIR="${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}
+
+        unset DPKG_ARCH
+        case ${{ matrix.job.target }} in
+          aarch64-*-linux-*) DPKG_ARCH=arm64 ;;
+          arm-*-linux-*hf) DPKG_ARCH=armhf ;;
+          i686-*-linux-*) DPKG_ARCH=i686 ;;
+          x86_64-*-linux-*) DPKG_ARCH=amd64 ;;
+          *) DPKG_ARCH=notset ;;
+        esac;
+
+        DPKG_NAME="${DPKG_BASENAME}_${DPKG_VERSION}_${DPKG_ARCH}.deb"
+        echo ::set-output name=DPKG_NAME::${DPKG_NAME}
+
+        # Binary
+        install -Dm755 "${{ steps.strip.outputs.BIN_PATH }}" "${DPKG_DIR}/usr/bin/${{ steps.strip.outputs.BIN_NAME }}"
+
+        # README and LICENSE
+        install -Dm644 "README.md" "${DPKG_DIR}/usr/share/doc/${DPKG_BASENAME}/README.md"
+        install -Dm644 "LICENSE-MIT" "${DPKG_DIR}/usr/share/doc/${DPKG_BASENAME}/LICENSE-MIT"
+        install -Dm644 "LICENSE-APACHE" "${DPKG_DIR}/usr/share/doc/${DPKG_BASENAME}/LICENSE-APACHE"
+        install -Dm644 "CHANGELOG.md" "${DPKG_DIR}/usr/share/doc/${DPKG_BASENAME}/changelog"
+        gzip -n --best "${DPKG_DIR}/usr/share/doc/${DPKG_BASENAME}/changelog"
+
+        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 }}
+
+        Files: *
+        Copyright: ${{ env.PROJECT_MAINTAINER }}
+        Copyright: $COPYRIGHT_YEARS ${{ env.PROJECT_MAINTAINER }}
+        License: Apache-2.0 or MIT
+
+        License: Apache-2.0
+          On Debian systems, the complete text of the Apache-2.0 can be found in the
+          file /usr/share/common-licenses/Apache-2.0.
+
+        License: MIT
+          Permission is hereby granted, free of charge, to any
+          person obtaining a copy of this software and associated
+          documentation files (the "Software"), to deal in the
+          Software without restriction, including without
+          limitation the rights to use, copy, modify, merge,
+          publish, distribute, sublicense, and/or sell copies of
+          the Software, and to permit persons to whom the Software
+          is furnished to do so, subject to the following
+          conditions:
+          .
+          The above copyright notice and this permission notice
+          shall be included in all copies or substantial portions
+          of the Software.
+          .
+          THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
+          ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
+          TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+          PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
+          SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+          CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+          OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
+          IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+          DEALINGS IN THE SOFTWARE.
+        EOF
+          chmod 644 "${DPKG_DIR}/usr/share/doc/${DPKG_BASENAME}/copyright"
+
+          # control file
+          mkdir -p "${DPKG_DIR}/DEBIAN"
+          cat > "${DPKG_DIR}/DEBIAN/control" <<EOF
+        Package: ${DPKG_BASENAME}
+        Version: ${DPKG_VERSION}
+        Section: utils
+        Priority: optional
+        Maintainer: ${{ env.PROJECT_MAINTAINER }}
+        Homepage: ${{ env.PROJECT_HOMEPAGE }}
+        Architecture: ${DPKG_ARCH}
+        Provides: ${{ env.PROJECT_NAME }}
+        Conflicts: ${DPKG_CONFLICTS}
+        Description: command-line tool to generate, analyze, convert and manipulate colors
+        EOF
+
+        DPKG_PATH="${DPKG_STAGING}/${DPKG_NAME}"
+        echo ::set-output name=DPKG_PATH::${DPKG_PATH}
+
+        # build dpkg
+        fakeroot dpkg-deb --build "${DPKG_DIR}" "${DPKG_PATH}"
+
+    - name: "Artifact upload: tarball"
+      uses: actions/upload-artifact@master
+      with:
+        name: ${{ steps.package.outputs.PKG_NAME }}
+        path: ${{ steps.package.outputs.PKG_PATH }}
+
+    - name: "Artifact upload: Debian package"
+      uses: actions/upload-artifact@master
+      if: steps.debian-package.outputs.DPKG_NAME
+      with:
+        name: ${{ steps.debian-package.outputs.DPKG_NAME }}
+        path: ${{ steps.debian-package.outputs.DPKG_PATH }}
+
+    - name: Check for release
+      id: is-release
+      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}
+
+    - name: Publish archives and packages
+      uses: softprops/action-gh-release@v1
+      if: steps.is-release.outputs.IS_RELEASE
+      with:
+        files: |
+          ${{ steps.package.outputs.PKG_PATH }}
+          ${{ steps.debian-package.outputs.DPKG_PATH }}
+      env:
+        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.travis.yml

@@ -1,80 +0,0 @@
-language: rust
-cache: cargo
-matrix:
-  include:
-    # Stable channel.
-    - os: linux
-      rust: stable
-      env: TARGET=x86_64-unknown-linux-gnu
-    - os: linux
-      rust: stable
-      env: TARGET=x86_64-unknown-linux-musl
-    - os: osx
-      rust: stable
-      env: TARGET=x86_64-apple-darwin
-    - os: windows
-      rust: stable
-      env: TARGET=x86_64-pc-windows-gnu
-
-    # Minimum Rust supported channel.
-    - os: linux
-      rust: 1.36.0
-      env: TARGET=x86_64-unknown-linux-gnu
-
-
-addons:
-  apt:
-    packages:
-      # needed to build deb packages
-      - fakeroot
-
-env:
-  global:
-    # Default target on travis-ci.
-    # Used as conditional check in the install stage
-    - HOST=x86_64-unknown-linux-gnu
-    # Used on the deployment script
-    - PROJECT_NAME=hexyl
-
-install:
-  # prevent target re-add error from rustup
-  - if [[ $TRAVIS_OS_NAME = linux && $HOST != $TARGET ]]; then rustup target add $TARGET; fi
-
-script:
-  # Incorporate TARGET env var to the build and test process
-  - cargo build --target $TARGET --verbose
-  - cargo test --target $TARGET --verbose
-  - cargo run --target $TARGET --example=simple
-
-before_deploy:
-  - bash ci/before_deploy.bash
-
-deploy:
-  provider: releases
-  # NOTE updating the `api_key.secure`
-  # - go to: https://github.com/settings/tokens/new
-  # - generate new token using `public_repo` scope
-  # - encrypt it using: `travis encrypt API_KEY_HERE`
-  # - paste the output below
-  api_key:
-    secure: "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"
-  # for uploading multiple files
-  file_glob: true
-  # NOTE explanation on each env variable
-  # - PROJECT_NAME: name of the project, set on the `env.global` above
-  # - TRAVIS_TAG: tag name that the build is being deployed for, usually the version number
-  # - TARGET: target triple of the build
-  file:
-    - $PROJECT_NAME-$TRAVIS_TAG-$TARGET.*
-    - $PROJECT_NAME*.deb
-  # don't delete artifacts from previous stage
-  skip_cleanup: true
-  on:
-    # deploy only if we push a tag
-    tags: true
-    # deploy only on stable channel that has TARGET env variable sets
-    condition: $TRAVIS_RUST_VERSION = stable && $TARGET != "x86_64-pc-windows-gnu"
-
-notifications:
-  email:
-    on_success: never

CHANGELOG.md

@@ -1,3 +1,48 @@
+# unreleased
+
+## Changes
+
+
+## Features
+
+
+## Bugfixes
+
+
+## Other
+
+
+## Packaging
+
+
+
+
+# v0.9.0
+
+## Changes
+
+- Breaking change (binary): setting the `-o/--display-offset` flag no longer overrides the value set by `--skip` [#115](https://github.com/sharkdp/hexyl/issues/115). The first displayed address is now the sum of the two values - this matches the behaviour of `xxd`.
+
+## Features
+
+- Allow relative and negative byte offsets (e.g. `hexyl --skip=-1block`), see #99 (@ErichDonGubler)
+- Added `-l` as another alias for '-n/--length' (`xxd` compatibility), see #121 and #135 (@TheDoctor314)
+
+## Bugfixes
+
+- Argument `--length` silently takes precedence over `--bytes`, see #105
+- Print warning on empty content, see #107 and #108
+- Disallow block sizes of zero, see #110
+- Fix newline appearing in `--version` output, see #131 and #133 (@scimas)
+
+## Other
+
+- Better diagnostic messages, see #98 (@ErichDonGubler)
+
+## Packaging
+
+- `hexyl` is now available on snapstore, see #116 (@purveshpatel511)
+
 # v0.8.0
 
 ## Features

CONTRIBUTING.md

@@ -0,0 +1,29 @@
+# Contributing
+
+Thank you for considering to contribute to `hexyl`!
+
+
+
+## Add an entry to the changelog
+
+If your contribution changes the behavior of `hexyl` (as opposed to a typo-fix
+in the documentation), please update the [`CHANGELOG.md`](CHANGELOG.md) file
+and describe your changes. This makes the release proess much easier and
+therefore helps to get your changes into a new `hexyl` release faster.
+
+The top of the `CHANGELOG` contains a *"unreleased"* section with a few
+subsections (Features, Bugfixes, …). Please add your entry to the subsection
+that best describes your change
+
+Entries follow this format:
+```
+- Short description of what has been changed, see #123 (@user)
+```
+Here, `#123` is the number of the original issue and/or your pull request.
+Please replace `@user` by your GitHub username.
+
+
+## Adding a new feature
+
+Please consider opening a [ticket](https://github.com/sharkdp/hexyl/issues/new)
+first in order to give us a chance to discuss the feature first.

Cargo.lock

@@ -1,139 +1,366 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
+[[package]]
+name = "aho-corasick"
+version = "0.7.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1e37cfd5e7657ada45f742d6e99ca5788580b5c529dc78faf11ece6dc702656f"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "ansi_term"
 version = "0.11.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ee49baf6cb617b853aa8d93bf420db2383fab46d314482ca2803b40d5fde979b"
 dependencies = [
- "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi",
 ]
 
 [[package]]
 name = "ansi_term"
 version = "0.12.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d52a9bb7ec0cf484c551830a7ce27bd20d67eac647e1befb56b0be4ee39a55d2"
 dependencies = [
- "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi",
+]
+
+[[package]]
+name = "anyhow"
+version = "1.0.42"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "595d3cfa7a60d4555cb5067b99f07142a08ea778de5cf993f7b75c7d8fabc486"
+
+[[package]]
+name = "assert_cmd"
+version = "1.0.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3d20831bd004dda4c7c372c19cdabff369f794a95e955b3f13fe460e3e1ae95f"
+dependencies = [
+ "bstr",
+ "doc-comment",
+ "predicates",
+ "predicates-core",
+ "predicates-tree",
+ "wait-timeout",
 ]
 
 [[package]]
 name = "atty"
 version = "0.2.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d9b39be18770d11421cdb1b9947a45dd3f37e93092cbf377614828a319d5fee8"
 dependencies = [
- "hermit-abi 0.1.13 (registry+https://github.com/rust-lang/crates.io-index)",
+ "hermit-abi",
- "libc 0.2.71 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc",
- "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi",
 ]
 
+[[package]]
+name = "autocfg"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cdb031dd78e28731d87d56cc8ffef4a8f36ca26c38fe2de700543e627f8a464a"
+
 [[package]]
 name = "bitflags"
 version = "1.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cf1de2fe8c75bc145a2f577add951f8134889b4795d47466a54a5c846d691693"
+
+[[package]]
+name = "bstr"
+version = "0.2.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "90682c8d613ad3373e66de8c6411e0ae2ab2571e879d2efbf73558cc66f21279"
+dependencies = [
+ "lazy_static",
+ "memchr",
+ "regex-automata",
+]
 
 [[package]]
 name = "clap"
-version = "2.33.1"
+version = "2.33.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "37e58ac78573c40708d45522f0d80fa2f01cc4f9b4e2bf749807255454312002"
 dependencies = [
- "ansi_term 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ansi_term 0.11.0",
- "atty 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "atty",
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+ "bitflags",
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+ "strsim",
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+ "term_size",
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+ "textwrap",
- "unicode-width 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode-width",
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+checksum = "e1267f4ac4f343772758f7b1bdcbe767c218bbab93bb432acbf5162bbf85a6c4"
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+ "num-traits",
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 dependencies = [
- "libc 0.2.71 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc",
 ]
 
 [[package]]
 name = "hexyl"
-version = "0.8.0"
+version = "0.9.0"
 dependencies = [
- "ansi_term 0.12.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ansi_term 0.12.1",
- "atty 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "anyhow",
- "clap 2.33.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "assert_cmd",
- "libc 0.2.71 (registry+https://github.com/rust-lang/crates.io-index)",
+ "atty",
+ "clap",
+ "libc",
+ "predicates",
+ "thiserror",
 ]
 
 [[package]]
-name = "libc"
+name = "itertools"
-version = "0.2.71"
+version = "0.10.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "69ddb889f9d0d08a67338271fa9b62996bc788c7796a5c18cf057420aaed5eaf"
+dependencies = [
+ "either",
+]
+
+[[package]]
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+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
+
+[[package]]
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+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "320cfe77175da3a483efed4bc0adc1968ca050b098ce4f2f1c13a56626128790"
+
+[[package]]
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+
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+
+[[package]]
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+checksum = "9a64b1ec5cda2586e284722486d802acf1f7dbdc623e2bfc57e65ca1cd099290"
+dependencies = [
+ "autocfg",
+]
+
+[[package]]
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+dependencies = [
+ "difflib",
+ "float-cmp",
+ "itertools",
+ "normalize-line-endings",
+ "predicates-core",
+ "regex",
+]
+
+[[package]]
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+
+[[package]]
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+checksum = "15f553275e5721409451eb85e15fd9a860a6e5ab4496eb215987502b5f5391f2"
+dependencies = [
+ "predicates-core",
+ "treeline",
+]
+
+[[package]]
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+version = "1.0.27"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f0d8caf72986c1a598726adc988bb5984792ef84f5ee5aa50209145ee8077038"
+dependencies = [
+ "unicode-xid",
+]
+
+[[package]]
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+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c3d0b9745dc2debf507c8422de05d7226cc1f0644216dfdfead988f9b1ab32a7"
+dependencies = [
+ "proc-macro2",
+]
+
+[[package]]
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+version = "1.5.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d07a8629359eb56f1e2fb1652bb04212c072a87ba68546a04065d525673ac461"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-syntax",
+]
+
+[[package]]
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+version = "0.1.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6c230d73fb8d8c1b9c0b3135c5142a8acee3a0558fb8db5cf1cb65f8d7862132"
+
+[[package]]
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 [[package]]
 name = "strsim"
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+checksum = "8ea5119cdb4c55b55d432abb513a0429384878c15dde60cc77b1c99de1a95a6a"
+
+[[package]]
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+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f71489ff30030d2ae598524f61326b902466f72a0fb1a8564c001cc63425bcc7"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-xid",
+]
 
 [[package]]
 name = "term_size"
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 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1e4129646ca0ed8f45d09b929036bafad5377103edd06e50bf574b353d2b08d9"
 dependencies = [
- "libc 0.2.71 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc",
- "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi",
 ]
 
 [[package]]
 name = "textwrap"
 version = "0.11.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d326610f408c7a4eb6f51c37c330e496b08506c9457c9d34287ecc38809fb060"
 dependencies = [
- "term_size 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "term_size",
- "unicode-width 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode-width",
 ]
 
 [[package]]
-name = "unicode-width"
+name = "thiserror"
-version = "0.1.7"
+version = "1.0.26"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "93119e4feac1cbe6c798c34d3a53ea0026b0b1de6a120deef895137c0529bfe2"
+dependencies = [
+ "thiserror-impl",
+]
 
 [[package]]
-name = "vec_map"
+name = "thiserror-impl"
-version = "0.8.2"
+version = "1.0.26"
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+checksum = "060d69a0afe7796bf42e9e2ff91f5ee691fb15c53d38b4b62a9a53eb23164745"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "treeline"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a7f741b240f1a48843f9b8e0444fb55fb2a4ff67293b50a9179dfd5ea67f8d41"
+
+[[package]]
+name = "unicode-width"
+version = "0.1.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9337591893a19b88d8d87f2cec1e73fad5cdfd10e5a6f349f498ad6ea2ffb1e3"
+
+[[package]]
+name = "unicode-xid"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8ccb82d61f80a663efe1f787a51b16b5a51e3314d6ac365b08639f52387b33f3"
+
+[[package]]
+name = "wait-timeout"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9f200f5b12eb75f8c1ed65abd4b2db8a6e1b138a20de009dacee265a2498f3f6"
+dependencies = [
+ "libc",
+]
 
 [[package]]
 name = "winapi"
-version = "0.3.8"
+version = "0.3.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5c839a674fcd7a98952e593242ea400abe93992746761e38641405d28b00f419"
 dependencies = [
- "winapi-i686-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi-i686-pc-windows-gnu",
- "winapi-x86_64-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi-x86_64-pc-windows-gnu",
 ]
 
 [[package]]
 name = "winapi-i686-pc-windows-gnu"
 version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
 
 [[package]]
 name = "winapi-x86_64-pc-windows-gnu"
 version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-
+checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
-[metadata]
-"checksum ansi_term 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ee49baf6cb617b853aa8d93bf420db2383fab46d314482ca2803b40d5fde979b"
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-"checksum atty 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)" = "d9b39be18770d11421cdb1b9947a45dd3f37e93092cbf377614828a319d5fee8"
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-"checksum clap 2.33.1 (registry+https://github.com/rust-lang/crates.io-index)" = "bdfa80d47f954d53a35a64987ca1422f495b8d6483c0fe9f7117b36c2a792129"
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-"checksum winapi-x86_64-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"

Cargo.toml

@@ -7,18 +7,25 @@ license = "MIT/Apache-2.0"
 name = "hexyl"
 readme = "README.md"
 repository = "https://github.com/sharkdp/hexyl"
-version = "0.8.0"
+version = "0.9.0"
 edition = "2018"
 
 [dependencies]
 ansi_term = "0.12"
+anyhow = "1.0.31"
 atty = "0.2"
 libc = "0.2"
+thiserror = "1.0.19"
 
 [dependencies.clap]
 version = "2"
+default-features = false
 features = ["suggestions", "color", "wrap_help"]
 
+[dev-dependencies]
+assert_cmd = "1.0"
+predicates = "2.0"
+
 [profile.release]
 lto = true
 codegen-units = 1

README.md

@@ -1,6 +1,6 @@
 ![](doc/logo.svg)
 
-[![Build Status](https://travis-ci.org/sharkdp/hexyl.svg?branch=master)](https://travis-ci.org/sharkdp/hexyl)
+[![CICD](https://github.com/sharkdp/hexyl/actions/workflows/CICD.yml/badge.svg)](https://github.com/sharkdp/hexyl/actions/workflows/CICD.yml)
 [![](https://img.shields.io/crates/l/hexyl.svg?colorB=22ba4c)](https://crates.io/crates/hexyl)
 ![](https://img.shields.io/crates/v/hexyl.svg?colorB=00aa88)
 
@@ -31,7 +31,7 @@ If you use an older version of Ubuntu, you can download
 the latest `.deb` package from the release page and install it via:
 
 ``` bash
-sudo dpkg -i hexyl_0.7.0_amd64.deb  # adapt version number and architecture
+sudo dpkg -i hexyl_0.9.0_amd64.deb  # adapt version number and architecture
 ```
 
 ### On Debian
@@ -57,24 +57,59 @@ pacman -S hexyl
 xbps-install hexyl
 ```
 
+### On Gentoo Linux
+
+Available in [dm9pZCAq overlay](https://github.com/gentoo-mirror/dm9pZCAq)
+
+```
+sudo eselect repository enable dm9pZCAq
+sudo emerge --sync dm9pZCAq
+sudo emerge sys-apps/hexyl::dm9pZCAq
+```
+
 ### On macOS
 
+Via [Homebrew](https://brew.sh):
+
 ```
 brew install hexyl
 ```
 
+...or via [MacPorts](https://www.macports.org):
+
+```
+sudo port install hexyl
+```
+
 ### On FreeBSD
 
 ```
 pkg install hexyl
 ```
 
+### on Termux
+```
+pkg install hexyl
+```
+or 
+```
+apt install hexyl
+```
+
 ### Via Nix
 
 ```
 nix-env -i hexyl
 ```
 
+### Via Guix
+
+```
+guix package -i hexyl
+```
+
+Or add the `hexyl` package in the list of packages to be installed in your system configuration (e.g., `/etc/config.scm`).
+
 ### On other distributions
 
 Check out the [release page](https://github.com/sharkdp/hexyl/releases) for binary builds.
@@ -87,11 +122,19 @@ or Windows Terminal since Windows 10 1903).
 
 ### Via cargo
 
-If you have Rust 1.36 or higher, you can install `hexyl` from source via `cargo`:
+If you have Rust 1.40 or higher, you can install `hexyl` from source via `cargo`:
 ```
 cargo install hexyl
 ```
 
+### Via snap package
+
+```
+sudo snap install hexyl
+```
+
+[Get it from the Snap Store](https://snapcraft.io/hexyl)
+
 ## License
 
 Licensed under either of

src/bin/hexyl.rs

@@ -9,14 +9,19 @@ use clap::{App, AppSettings, Arg};
 
 use atty::Stream;
 
+use anyhow::{anyhow, Context, Error as AnyhowError};
+
+use thiserror::Error as ThisError;
+
 use hexyl::{BorderStyle, Input, Printer};
 
-fn run() -> Result<(), Box<dyn std::error::Error>> {
+fn run() -> Result<(), AnyhowError> {
     let app = App::new(crate_name!())
         .setting(AppSettings::ColorAuto)
         .setting(AppSettings::ColoredHelp)
         .setting(AppSettings::DeriveDisplayOrder)
         .setting(AppSettings::UnifiedHelpMessage)
+        .max_term_width(90)
         .version(crate_version!())
         .about(crate_description!())
         .arg(
@@ -31,7 +36,8 @@ fn run() -> Result<(), Box<dyn std::error::Error>> {
                 .value_name("N")
                 .help(
                     "Only read N bytes from the input. The N argument can also include a \
-                      unit with a decimal prefix (kB, MB, ..) or binary prefix (kiB, MiB, ..).\n\
+                     unit with a decimal prefix (kB, MB, ..) or binary prefix (kiB, MiB, ..). \
+                     The short option '-l' can be used as an alias.\n\
                      Examples: --length=64, --length=4KiB",
                 ),
         )
@@ -41,8 +47,17 @@ fn run() -> Result<(), Box<dyn std::error::Error>> {
                 .long("bytes")
                 .takes_value(true)
                 .value_name("N")
+                .conflicts_with("length")
                 .help("An alias for -n/--length"),
         )
+        .arg(
+            Arg::with_name("count")
+                .short("l")
+                .takes_value(true)
+                .value_name("N")
+                .hidden(true)
+                .help("Yet another alias for -n/--length"),
+        )
         .arg(
             Arg::with_name("skip")
                 .short("s")
@@ -51,7 +66,8 @@ fn run() -> Result<(), Box<dyn std::error::Error>> {
                 .value_name("N")
                 .help(
                     "Skip the first N bytes of the input. The N argument can also include \
-                      a unit (see `--length` for details)",
+                     a unit (see `--length` for details)\n\
+                     A negative value is valid and will seek from the end of the file.",
                 ),
         )
         .arg(
@@ -93,7 +109,10 @@ fn run() -> Result<(), Box<dyn std::error::Error>> {
                 .value_name("STYLE")
                 .possible_values(&["unicode", "ascii", "none"])
                 .default_value("unicode")
-                .help("Whether to draw a border with Unicode characters, ASCII characters, or none at all"),
+                .help(
+                    "Whether to draw a border with Unicode characters, ASCII characters, \
+                    or none at all",
+                ),
         )
         .arg(
             Arg::with_name("display_offset")
@@ -101,39 +120,82 @@ fn run() -> Result<(), Box<dyn std::error::Error>> {
                 .long("display-offset")
                 .takes_value(true)
                 .value_name("N")
-                .help("Add N bytes to the displayed file position. The N argument can also include \
+                .help(
-                a unit (see `--length` for details)"),
+                    "Add N bytes to the displayed file position. The N argument can also \
+                    include a unit (see `--length` for details)\n\
+                    A negative value is valid and calculates an offset relative to the \
+                    end of the file.",
+                ),
         );
 
     let matches = app.get_matches_safe()?;
 
     let stdin = io::stdin();
 
-    let mut reader: Input = match matches.value_of("FILE") {
+    let mut reader = match matches.value_of("FILE") {
         Some(filename) => Input::File(File::open(filename)?),
         None => Input::Stdin(stdin.lock()),
     };
 
     let block_size = matches
         .value_of("block_size")
-        .and_then(|bs| bs.parse().ok().and_then(PositiveI64::new))
+        .map(|bs| {
+            bs.parse::<i64>().map_err(|e| anyhow!(e)).and_then(|x| {
+                PositiveI64::new(x).ok_or_else(|| anyhow!("block size argument must be positive"))
+            })
+        })
+        .transpose()?
         .unwrap_or_else(|| PositiveI64::new(512).unwrap());
 
     let skip_arg = matches
         .value_of("skip")
-        .and_then(|s| parse_byte_count(s, block_size));
+        .map(|s| {
+            parse_byte_offset(s, block_size).context(anyhow!(
+                "failed to parse `--skip` arg {:?} as byte count",
+                s
+            ))
+        })
+        .transpose()?;
 
-    if let Some(skip) = skip_arg {
+    let skip_offset = if let Some(ByteOffset { kind, value }) = skip_arg {
-        reader.seek(SeekFrom::Current(skip.into_inner()))?;
+        let value = value.into_inner();
+        reader
+            .seek(match kind {
+                ByteOffsetKind::ForwardFromBeginning | ByteOffsetKind::ForwardFromLastOffset => {
+                    SeekFrom::Current(value)
                 }
+                ByteOffsetKind::BackwardFromEnd => SeekFrom::End(value.checked_neg().unwrap()),
+            })
+            .map_err(|_| {
+                anyhow!(
+                    "Failed to jump to the desired input position. \
+                     This could be caused by a negative offset that is too large or by \
+                     an input that is not seek-able (e.g. if the input comes from a pipe)."
+                )
+            })?
+    } else {
+        0
+    };
 
-    let length_arg = matches
+    let parse_byte_count = |s| -> Result<u64, AnyhowError> {
+        Ok(parse_byte_offset(s, block_size)?
+            .assume_forward_offset_from_start()?
+            .into())
+    };
+
+    let mut reader = if let Some(length) = matches
         .value_of("length")
-        .or_else(|| matches.value_of("bytes"));
+        .or_else(|| matches.value_of("bytes"))
-
+        .or_else(|| matches.value_of("count"))
-    let mut reader = if let Some(length) = length_arg.and_then(|s| parse_byte_count(s, block_size))
+        .map(|s| {
+            parse_byte_count(s).context(anyhow!(
+                "failed to parse `--length` arg {:?} as byte count",
+                s
+            ))
+        })
+        .transpose()?
     {
-        Box::new(reader.take(length.into()))
+        Box::new(reader.take(length))
     } else {
         reader.into_inner()
     };
@@ -152,19 +214,24 @@ fn run() -> Result<(), Box<dyn std::error::Error>> {
 
     let squeeze = !matches.is_present("nosqueezing");
 
-    let display_offset = matches
+    let display_offset: u64 = matches
         .value_of("display_offset")
-        .and_then(|s| parse_byte_count(s, block_size))
+        .map(|s| {
-        .or(skip_arg)
+            parse_byte_count(s).context(anyhow!(
-        .unwrap_or_default()
+                "failed to parse `--display-offset` arg {:?} as byte count",
+                s
+            ))
+        })
+        .transpose()?
+        .unwrap_or(0)
         .into();
 
     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);
+    printer.display_offset(skip_offset + display_offset);
-    printer.print_all(&mut reader)?;
+    printer.print_all(&mut reader).map_err(|e| anyhow!(e))?;
 
     Ok(())
 }
@@ -178,28 +245,57 @@ fn main() {
 
     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 => {
+                clap::ErrorKind::HelpDisplayed => {
+                    eprint!("{}", clap_err); // Clap errors already have newlines
+                    std::process::exit(0)
+                }
+                clap::ErrorKind::VersionDisplayed => {
+                    // Version output in clap 2.33.1 (dep as of now) doesn't have a newline
+                    // and the fix is not included even in the latest stable release
+                    println!("");
                     std::process::exit(0)
                 }
                 _ => (),
             }
         } else {
-            eprintln!("Error: {}", err);
+            eprintln!("Error: {:?}", err);
         }
         std::process::exit(1);
     }
 }
 
+#[derive(Clone, Copy, Debug, Default, Hash, Eq, Ord, PartialEq, PartialOrd)]
+pub struct NonNegativeI64(i64);
+
+impl NonNegativeI64 {
+    pub fn new(x: i64) -> Option<Self> {
+        if x.is_negative() {
+            None
+        } else {
+            Some(Self(x))
+        }
+    }
+
+    pub fn into_inner(self) -> i64 {
+        self.0
+    }
+}
+
+impl Into<u64> for NonNegativeI64 {
+    fn into(self) -> u64 {
+        u64::try_from(self.0)
+            .expect("invariant broken: NonNegativeI64 should contain a non-negative i64 value")
+    }
+}
+
 #[derive(Clone, Copy, Debug, Default, Hash, Eq, Ord, PartialEq, PartialOrd)]
 pub struct PositiveI64(i64);
 
 impl PositiveI64 {
     pub fn new(x: i64) -> Option<Self> {
-        if x.is_negative() {
+        if x < 1 {
             None
         } else {
             Some(Self(x))
@@ -218,34 +314,118 @@ impl Into<u64> for PositiveI64 {
     }
 }
 
-fn parse_byte_count(n: &str, block_size: PositiveI64) -> Option<PositiveI64> {
+const HEX_PREFIX: &str = "0x";
-    const HEX_PREFIX: &str = "0x";
 
-    let n = {
+#[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
-        let mut chars = n.chars();
+enum ByteOffsetKind {
-        match chars.next()? {
+    ForwardFromBeginning,
-            '+' => chars.as_str(),
+    ForwardFromLastOffset,
-            '-' => return None,
+    BackwardFromEnd,
-            _ => n,
+}
+
+#[derive(Clone, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
+struct ByteOffset {
+    value: NonNegativeI64,
+    kind: ByteOffsetKind,
+}
+
+#[derive(Clone, Debug, ThisError)]
+#[error(
+    "negative offset specified, but only positive offsets (counts) are accepted in this context"
+)]
+struct NegativeOffsetSpecifiedError;
+
+impl ByteOffset {
+    fn assume_forward_offset_from_start(
+        &self,
+    ) -> Result<NonNegativeI64, NegativeOffsetSpecifiedError> {
+        let &Self { value, kind } = self;
+        match kind {
+            ByteOffsetKind::ForwardFromBeginning | ByteOffsetKind::ForwardFromLastOffset => {
+                Ok(value)
             }
+            ByteOffsetKind::BackwardFromEnd => Err(NegativeOffsetSpecifiedError),
+        }
+    }
+}
+
+#[derive(Clone, Debug, Eq, PartialEq, ThisError)]
+enum ByteOffsetParseError {
+    #[error("no character data found, did you forget to write it?")]
+    Empty,
+    #[error("no digits found after sign, did you forget to write them?")]
+    EmptyAfterSign,
+    #[error(
+        "found {0:?} sign after hex prefix ({:?}); signs should go before it",
+        HEX_PREFIX
+    )]
+    SignFoundAfterHexPrefix(char),
+    #[error("{0:?} is not of the expected form <pos-integer>[<unit>]")]
+    InvalidNumAndUnit(String),
+    #[error("{0:?} is a valid unit, but an integer should come before it")]
+    EmptyWithUnit(String),
+    #[error("invalid unit {0:?}")]
+    InvalidUnit(String),
+    #[error("failed to parse integer part")]
+    ParseNum(#[source] std::num::ParseIntError),
+    #[error("count multipled by the unit overflowed a signed 64-bit integer; are you sure it should be that big?")]
+    UnitMultiplicationOverflow,
+}
+
+fn parse_byte_offset(n: &str, block_size: PositiveI64) -> Result<ByteOffset, ByteOffsetParseError> {
+    use ByteOffsetParseError::*;
+
+    let (n, kind) = {
+        let mut chars = n.chars();
+        let next_char = chars.next();
+        let check_empty_after_sign = || {
+            if chars.clone().next().is_none() {
+                Err(EmptyAfterSign)
+            } else {
+                Ok(chars.as_str())
+            }
+        };
+        match next_char {
+            Some('+') => (
+                check_empty_after_sign()?,
+                ByteOffsetKind::ForwardFromLastOffset,
+            ),
+            Some('-') => (check_empty_after_sign()?, ByteOffsetKind::BackwardFromEnd),
+            None => return Err(Empty),
+            _ => (n, ByteOffsetKind::ForwardFromBeginning),
+        }
+    };
+
+    let into_byte_offset = |value| {
+        Ok(ByteOffset {
+            value: NonNegativeI64::new(value).unwrap(),
+            kind,
+        })
     };
 
     if n.starts_with(HEX_PREFIX) {
         let n = &n[HEX_PREFIX.len()..];
-        match n.chars().next() {
+        let mut chars = n.chars();
-            Some('+') | Some('-') => return None,
+        match chars.next() {
+            Some(c @ '+') | Some(c @ '-') => {
+                return if chars.next().is_none() {
+                    Err(EmptyAfterSign)
+                } else {
+                    Err(SignFoundAfterHexPrefix(c))
+                }
+            }
             _ => (),
         }
-        return i64::from_str_radix(n, 16).ok().and_then(PositiveI64::new);
+        return i64::from_str_radix(n, 16)
+            .map(into_byte_offset)
+            .map_err(ParseNum)?;
     }
 
-    let (n, unit_multiplier) = match n.chars().position(|c| !c.is_ascii_digit()) {
+    let (num, unit) = match n.chars().position(|c| !c.is_ascii_digit()) {
         Some(unit_begin_idx) => {
             let (n, raw_unit) = n.split_at(unit_begin_idx);
-            let raw_unit = raw_unit.to_lowercase();
+            let raw_unit_lower = raw_unit.to_lowercase();
-            (
+            let multiplier = [
-                n,
-                [
                 ("b", 1),
                 ("kb", 1000i64.pow(1)),
                 ("mb", 1000i64.pow(2)),
@@ -260,93 +440,121 @@ fn parse_byte_count(n: &str, block_size: PositiveI64) -> Option<PositiveI64> {
             .iter()
             .cloned()
             .find_map(|(unit, multiplier)| {
-                    if unit == raw_unit {
+                if unit == raw_unit_lower {
                     Some(multiplier)
                 } else {
                     None
                 }
-                })?,
+            })
-            )
+            .ok_or_else(|| InvalidUnit(raw_unit.to_owned()));
+            (n, multiplier.map(|m| (Some(raw_unit), m)))
         }
-        None => (n, 1),
+        None => (n, Ok((None, 1))),
     };
 
-    n.parse::<i64>()
+    match (num.parse::<i64>(), unit) {
-        .ok()?
+        (Ok(num), Ok((_raw_unit, unit_multiplier))) => num
             .checked_mul(unit_multiplier)
-        .and_then(PositiveI64::new)
+            .ok_or_else(|| UnitMultiplicationOverflow)
+            .and_then(into_byte_offset),
+        (Ok(_), Err(e)) => Err(e),
+        (Err(e), Ok((raw_unit, _unit_multiplier))) => match raw_unit {
+            Some(raw_unit) if num.is_empty() => Err(EmptyWithUnit(raw_unit.to_owned())),
+            _ => Err(ParseNum(e)),
+        },
+        (Err(_), Err(_)) => Err(InvalidNumAndUnit(n.to_owned())),
+    }
 }
 
 #[test]
-fn test_parse_byte_count() {
+fn test_parse_byte_offset() {
+    use ByteOffsetParseError::*;
+
     macro_rules! success {
-        ($input: expr, $expected: expr) => {
+        ($input: expr, $expected_kind: ident $expected_value: expr) => {
-            success!($input, 512, $expected)
+            success!($input, $expected_kind $expected_value; block_size: 512)
         };
-        ($input: expr, $block_size: expr, $expected: expr) => {
+        ($input: expr, $expected_kind: ident $expected_value: expr; block_size: $block_size: expr) => {
             assert_eq!(
-                parse_byte_count($input, PositiveI64::new($block_size).unwrap()),
+                parse_byte_offset($input, PositiveI64::new($block_size).unwrap()),
-                Some(PositiveI64::new($expected).unwrap())
+                Ok(
+                    ByteOffset {
+                        value: NonNegativeI64::new($expected_value).unwrap(),
+                        kind: ByteOffsetKind::$expected_kind,
+                    }
+                ),
             );
         };
     }
 
     macro_rules! error {
-        ($input: expr) => {
+        ($input: expr, $expected_err: expr) => {
             assert_eq!(
-                parse_byte_count($input, PositiveI64::new(512).unwrap()),
+                parse_byte_offset($input, PositiveI64::new(512).unwrap()),
-                None
+                Err($expected_err),
             );
         };
     }
 
-    success!("0", 0);
+    success!("0", ForwardFromBeginning 0);
-    success!("1", 1);
+    success!("1", ForwardFromBeginning 1);
-    success!("1", 1);
+    success!("1", ForwardFromBeginning 1);
-    success!("100", 100);
+    success!("100", ForwardFromBeginning 100);
-    success!("+100", 100);
+    success!("+100", ForwardFromLastOffset 100);
 
-    success!("1KB", 1000);
+    success!("0x0", ForwardFromBeginning 0);
-    success!("2MB", 2000000);
+    success!("0xf", ForwardFromBeginning 15);
-    success!("3GB", 3000000000);
+    success!("0xdeadbeef", ForwardFromBeginning 3_735_928_559);
-    success!("4TB", 4000000000000);
-    success!("+4TB", 4000000000000);
 
-    success!("1GiB", 1073741824);
+    success!("1KB", ForwardFromBeginning 1000);
-    success!("2TiB", 2199023255552);
+    success!("2MB", ForwardFromBeginning 2000000);
-    success!("+2TiB", 2199023255552);
+    success!("3GB", ForwardFromBeginning 3000000000);
+    success!("4TB", ForwardFromBeginning 4000000000000);
+    success!("+4TB", ForwardFromLastOffset 4000000000000);
 
-    success!("0xff", 255);
+    success!("1GiB", ForwardFromBeginning 1073741824);
-    success!("0xEE", 238);
+    success!("2TiB", ForwardFromBeginning 2199023255552);
-    success!("+0xFF", 255);
+    success!("+2TiB", ForwardFromLastOffset 2199023255552);
 
-    success!("1block", 512, 512);
+    success!("0xff", ForwardFromBeginning 255);
-    success!("2block", 512, 1024);
+    success!("0xEE", ForwardFromBeginning 238);
-    success!("1block", 4, 4);
+    success!("+0xFF", ForwardFromLastOffset 255);
-    success!("2block", 4, 8);
+
+    success!("1block", ForwardFromBeginning 512; block_size: 512);
+    success!("2block", ForwardFromBeginning 1024; block_size: 512);
+    success!("1block", ForwardFromBeginning 4; block_size: 4);
+    success!("2block", ForwardFromBeginning 8; block_size: 4);
 
     // empty string is invalid
-    error!("");
+    error!("", Empty);
     // These are also bad.
-    error!("+");
+    error!("+", EmptyAfterSign);
-    error!("-");
+    error!("-", EmptyAfterSign);
-    error!("K");
+    error!("K", InvalidNumAndUnit("K".to_owned()));
-    error!("k");
+    error!("k", InvalidNumAndUnit("k".to_owned()));
-    error!("m");
+    error!("m", InvalidNumAndUnit("m".to_owned()));
-    error!("block");
+    error!("block", EmptyWithUnit("block".to_owned()));
     // leading/trailing space is invalid
-    error!(" 0");
+    error!(" 0", InvalidNumAndUnit(" 0".to_owned()));
-    error!("0 ");
+    error!("0 ", InvalidUnit(" ".to_owned()));
-    // Negatives make no sense for byte counts
+    // Signs after the hex prefix make no sense
-    error!("-1");
+    error!("0x-12", SignFoundAfterHexPrefix('-'));
-    error!("0x-12");
     // This was previously accepted but shouldn't be.
-    error!("0x+12");
+    error!("0x+12", SignFoundAfterHexPrefix('+'));
     // invalid suffix
-    error!("1234asdf");
+    error!("1234asdf", InvalidUnit("asdf".to_owned()));
     // bad numbers
-    error!("asdf1234");
+    error!("asdf1234", InvalidNumAndUnit("asdf1234".to_owned()));
-    error!("a1s2d3f4");
+    error!("a1s2d3f4", InvalidNumAndUnit("a1s2d3f4".to_owned()));
     // multiplication overflows u64
-    error!("20000000TiB");
+    error!("20000000TiB", UnitMultiplicationOverflow);
+
+    assert!(
+        match parse_byte_offset("99999999999999999999", PositiveI64::new(512).unwrap()) {
+            // We can't check against the kind of the `ParseIntError`, so we'll just make sure it's the
+            // same as trying to do the parse directly.
+            Err(ParseNum(e)) => e == "99999999999999999999".parse::<i64>().unwrap_err(),
+            _ => false,
+        }
+    );
 }

src/lib.rs

@@ -408,7 +408,7 @@ impl<'a, Writer: Write> Printer<'a, Writer> {
     pub fn print_all<Reader: Read>(
         &mut self,
         mut reader: Reader,
-    ) -> Result<(), Box<dyn std::error::Error>> {
+    ) -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
         let mut buffer = [0; BUFFER_SIZE];
         'mainloop: loop {
             let size = reader.read(&mut buffer)?;
@@ -428,8 +428,14 @@ impl<'a, Writer: Write> Printer<'a, Writer> {
 
         // Finish last line
         self.print_textline().ok();
+
         if !self.header_was_printed() {
             self.header();
+            writeln!(
+                self.writer,
+                "│        │ No content to print     │                         │        │        │"
+            )
+            .ok();
         }
         self.footer();
 
@@ -459,6 +465,7 @@ mod tests {
         let input = io::empty();
         let expected_string = "\
 ┌────────┬─────────────────────────┬─────────────────────────┬────────┬────────┐
+│        │ No content to print     │                         │        │        │
 └────────┴─────────────────────────┴─────────────────────────┴────────┴────────┘
 "
         .to_owned();

tests/examples/.gitattributes

@@ -0,0 +1 @@
+ascii text eol=lf

tests/examples/ascii

@@ -0,0 +1 @@
+0123456789abcde

tests/integration_tests.rs

@@ -0,0 +1,205 @@
+use assert_cmd::Command;
+
+fn hexyl() -> Command {
+    let mut cmd = Command::cargo_bin("hexyl").unwrap();
+    cmd.current_dir("tests/examples");
+    cmd
+}
+
+mod basic {
+    use super::hexyl;
+
+    #[test]
+    fn can_print_simple_ascii_file() {
+        hexyl()
+        .arg("ascii")
+        .arg("--color=never")
+        .assert()
+        .success()
+        .stdout(
+            "┌────────┬─────────────────────────┬─────────────────────────┬────────┬────────┐\n\
+             │00000000│ 30 31 32 33 34 35 36 37 ┊ 38 39 61 62 63 64 65 0a │01234567┊89abcde_│\n\
+             └────────┴─────────────────────────┴─────────────────────────┴────────┴────────┘\n",
+        );
+    }
+
+    #[test]
+    fn can_read_input_from_stdin() {
+        hexyl()
+        .arg("--color=never")
+        .write_stdin("abc")
+        .assert()
+        .success()
+        .stdout(
+            "┌────────┬─────────────────────────┬─────────────────────────┬────────┬────────┐\n\
+             │00000000│ 61 62 63                ┊                         │abc     ┊        │\n\
+             └────────┴─────────────────────────┴─────────────────────────┴────────┴────────┘\n",
+        );
+    }
+
+    #[test]
+    fn fails_on_non_existing_input() {
+        hexyl().arg("non-existing").assert().failure();
+    }
+
+    #[test]
+    fn prints_warning_on_empty_content() {
+        hexyl()
+        .arg("empty")
+        .arg("--color=never")
+        .assert()
+        .success()
+        .stdout(
+            "┌────────┬─────────────────────────┬─────────────────────────┬────────┬────────┐\n\
+             │        │ No content to print     │                         │        │        │\n\
+             └────────┴─────────────────────────┴─────────────────────────┴────────┴────────┘\n",
+        );
+    }
+}
+
+mod length {
+    use super::hexyl;
+
+    #[test]
+    fn length_restricts_output_size() {
+        hexyl()
+        .arg("hello_world_elf64")
+        .arg("--color=never")
+        .arg("--length=32")
+        .assert()
+        .success()
+        .stdout(
+            "┌────────┬─────────────────────────┬─────────────────────────┬────────┬────────┐\n\
+             │00000000│ 7f 45 4c 46 02 01 01 00 ┊ 00 00 00 00 00 00 00 00 │•ELF•••0┊00000000│\n\
+             │00000010│ 02 00 3e 00 01 00 00 00 ┊ 00 10 40 00 00 00 00 00 │•0>0•000┊0•@00000│\n\
+             └────────┴─────────────────────────┴─────────────────────────┴────────┴────────┘\n",
+        );
+    }
+
+    #[test]
+    fn fail_if_length_and_bytes_options_are_used_simultaneously() {
+        hexyl()
+            .arg("hello_world_elf64")
+            .arg("--length=32")
+            .arg("--bytes=10")
+            .assert()
+            .failure();
+    }
+}
+
+mod skip {
+    use super::hexyl;
+
+    #[test]
+    fn basic() {
+        hexyl()
+        .arg("ascii")
+        .arg("--color=never")
+        .arg("--skip=2")
+        .arg("--length=4")
+        .assert()
+        .success()
+        .stdout(
+            "┌────────┬─────────────────────────┬─────────────────────────┬────────┬────────┐\n\
+             │00000002│ 32 33 34 35             ┊                         │2345    ┊        │\n\
+             └────────┴─────────────────────────┴─────────────────────────┴────────┴────────┘\n",
+        );
+    }
+
+    #[test]
+    fn prints_warning_when_skipping_past_the_end() {
+        hexyl()
+        .arg("ascii")
+        .arg("--color=never")
+        .arg("--skip=1000")
+        .assert()
+        .success()
+        .stdout(
+            "┌────────┬─────────────────────────┬─────────────────────────┬────────┬────────┐\n\
+             │        │ No content to print     │                         │        │        │\n\
+             └────────┴─────────────────────────┴─────────────────────────┴────────┴────────┘\n",
+        );
+    }
+
+    #[test]
+    fn negative_offset() {
+        hexyl()
+        .arg("ascii")
+        .arg("--color=never")
+        .arg("--skip=-4")
+        .arg("--length=3")
+        .assert()
+        .success()
+        .stdout(
+            "┌────────┬─────────────────────────┬─────────────────────────┬────────┬────────┐\n\
+             │0000000c│ 63 64 65                ┊                         │cde     ┊        │\n\
+             └────────┴─────────────────────────┴─────────────────────────┴────────┴────────┘\n",
+        );
+    }
+
+    #[test]
+    fn fails_if_negative_offset_is_too_large() {
+        hexyl()
+            .arg("ascii")
+            .arg("--color=never")
+            .arg("--skip=-1MiB")
+            .assert()
+            .failure()
+            .stderr(predicates::str::contains("Failed to jump"));
+    }
+}
+
+mod display_offset {
+    use super::hexyl;
+
+    #[test]
+    fn basic() {
+        hexyl()
+        .arg("ascii")
+        .arg("--color=never")
+        .arg("--display-offset=0xc0ffee")
+        .assert()
+        .success()
+        .stdout(
+            "┌────────┬─────────────────────────┬─────────────────────────┬────────┬────────┐\n\
+             │00c0ffee│ 30 31 32 33 34 35 36 37 ┊ 38 39 61 62 63 64 65 0a │01234567┊89abcde_│\n\
+             └────────┴─────────────────────────┴─────────────────────────┴────────┴────────┘\n",
+        );
+    }
+
+    #[test]
+    fn display_offset_and_skip() {
+        hexyl()
+        .arg("hello_world_elf64")
+        .arg("--color=never")
+        .arg("--display-offset=0x20")
+        .arg("--skip=0x10")
+        .arg("--length=0x10")
+        .assert()
+        .success()
+        .stdout(
+            "┌────────┬─────────────────────────┬─────────────────────────┬────────┬────────┐\n\
+             │00000030│ 02 00 3e 00 01 00 00 00 ┊ 00 10 40 00 00 00 00 00 │•0>0•000┊0•@00000│\n\
+             └────────┴─────────────────────────┴─────────────────────────┴────────┴────────┘\n",
+        );
+    }
+}
+
+mod blocksize {
+    use super::hexyl;
+
+    #[test]
+    fn fails_for_zero_or_negative_blocksize() {
+        hexyl()
+            .arg("ascii")
+            .arg("--block-size=0")
+            .assert()
+            .failure();
+
+        hexyl()
+            .arg("ascii")
+            .arg("--block-size=-16")
+            .assert()
+            .failure();
+    }
+}