Initial commit

hw07_file_copying/README.md

@@ -0,0 +1,37 @@
+## Домашнее задание №7 «Утилита для копирования файлов»
+Необходимо реализовать утилиту копирования файлов (упрощенный аналог `dd`).
+
+Тулза должна принимать следующие аргументы:
+* путь к исходному файлу (`-from`);
+* путь к копии (`-to`);
+* отступ в источнике (`-offset`), по умолчанию - 0;
+* количество копируемых байт (`-limit`), по умолчанию - 0 (весь файл из `-from`).
+
+Особенности:
+* offset больше, чем размер файла - невалидная ситуация;
+* limit больше, чем размер файла - валидная ситуация, копируется исходный файл до его EOF;
+* программа может НЕ обрабатывать файлы, у которых неизвестна длина (например, /dev/urandom);
+
+Также необходимо выводить в консоль прогресс копирования в процентах (%),
+допускается использовать для этого стороннюю библиотеку.
+
+Юнит-тесты могут использовать файлы из `testdata` (разрешено добавить свои, но запрещено удалять имеющиеся)
+и должны чистить за собой создаваемые файлы (или работать в `/tmp`).
+
+При необходимости можно выделять дополнительные функции / ошибки.
+
+**(*) Дополнительное задание: реализовать прогресс-бар самостоятельно.**
+
+### Критерии оценки
+- Пайплайн зелёный - 4 балла
+- Добавлены юнит-тесты - до 4 баллов
+- Понятность и чистота кода - до 2 баллов
+- Дополнительное задание на баллы не влияет
+
+#### Зачёт от 7 баллов
+
+### Подсказки
+- `github.com/cheggaaa/pb`
+- `os.OpenFile`, `os.Create`, `os.FileMode`
+- `io.CopyN`
+- `os.CreateTemp`

hw07_file_copying/copy.go

@@ -0,0 +1,15 @@
+package main
+
+import (
+	"errors"
+)
+
+var (
+	ErrUnsupportedFile       = errors.New("unsupported file")
+	ErrOffsetExceedsFileSize = errors.New("offset exceeds file size")
+)
+
+func Copy(fromPath, toPath string, offset, limit int64) error {
+	// Place your code here.
+	return nil
+}

hw07_file_copying/copy_test.go

@@ -0,0 +1,7 @@
+package main
+
+import "testing"
+
+func TestCopy(t *testing.T) {
+	// Place your code here.
+}

hw07_file_copying/go.mod

@@ -0,0 +1,3 @@
+module github.com/fixme_my_friend/hw07_file_copying
+
+go 1.19

hw07_file_copying/main.go

@@ -0,0 +1,22 @@
+package main
+
+import (
+	"flag"
+)
+
+var (
+	from, to      string
+	limit, offset int64
+)
+
+func init() {
+	flag.StringVar(&from, "from", "", "file to read from")
+	flag.StringVar(&to, "to", "", "file to write to")
+	flag.Int64Var(&limit, "limit", 0, "limit of bytes to copy")
+	flag.Int64Var(&offset, "offset", 0, "offset in input file")
+}
+
+func main() {
+	flag.Parse()
+	// Place your code here.
+}

hw07_file_copying/test.sh

@@ -0,0 +1,25 @@
+#!/usr/bin/env bash
+set -xeuo pipefail
+
+go build -o go-cp
+
+./go-cp -from testdata/input.txt -to out.txt
+cmp out.txt testdata/out_offset0_limit0.txt
+
+./go-cp -from testdata/input.txt -to out.txt -limit 10
+cmp out.txt testdata/out_offset0_limit10.txt
+
+./go-cp -from testdata/input.txt -to out.txt -limit 1000
+cmp out.txt testdata/out_offset0_limit1000.txt
+
+./go-cp -from testdata/input.txt -to out.txt -limit 10000
+cmp out.txt testdata/out_offset0_limit10000.txt
+
+./go-cp -from testdata/input.txt -to out.txt -offset 100 -limit 1000
+cmp out.txt testdata/out_offset100_limit1000.txt
+
+./go-cp -from testdata/input.txt -to out.txt -offset 6000 -limit 1000
+cmp out.txt testdata/out_offset6000_limit1000.txt
+
+rm -f go-cp out.txt
+echo "PASS"

hw07_file_copying/testdata/input.txt

@@ -0,0 +1,125 @@
+Go
+Documents
+Packages
+The Project
+Help
+Blog
+Play
+Search
+
+Getting Started
+Install the Go tools
+Test your installation
+Installing extra Go versions
+Uninstalling Go
+Getting help
+Download the Go distribution
+Download Go
+Click here to visit the downloads page
+Official binary distributions are available for the FreeBSD (release 10-STABLE and above), Linux, macOS (10.10 and above), and Windows operating systems and the 32-bit (386) and 64-bit (amd64) x86 processor architectures.
+
+If a binary distribution is not available for your combination of operating system and architecture, try installing from source or installing gccgo instead of gc.
+
+System requirements
+Go binary distributions are available for these supported operating systems and architectures. Please ensure your system meets these requirements before proceeding. If your OS or architecture is not on the list, you may be able to install from source or use gccgo instead.
+
+Operating system	Architectures	Notes
+FreeBSD 10.3 or later	amd64, 386	Debian GNU/kFreeBSD not supported
+Linux 2.6.23 or later with glibc	amd64, 386, arm, arm64,
+s390x, ppc64le	CentOS/RHEL 5.x not supported.
+Install from source for other libc.
+macOS 10.10 or later	amd64	use the clang or gcc† that comes with Xcode‡ for cgo support
+Windows 7, Server 2008R2 or later	amd64, 386	use MinGW (386) or MinGW-W64 (amd64) gcc†.
+No need for cygwin or msys.
+†A C compiler is required only if you plan to use cgo.
+‡You only need to install the command line tools for Xcode. If you have already installed Xcode 4.3+, you can install it from the Components tab of the Downloads preferences panel.
+
+Install the Go tools
+If you are upgrading from an older version of Go you must first remove the existing version.
+
+Linux, macOS, and FreeBSD tarballs
+Download the archive and extract it into /usr/local, creating a Go tree in /usr/local/go. For example:
+
+tar -C /usr/local -xzf go$VERSION.$OS-$ARCH.tar.gz
+Choose the archive file appropriate for your installation. For instance, if you are installing Go version 1.2.1 for 64-bit x86 on Linux, the archive you want is called go1.2.1.linux-amd64.tar.gz.
+
+(Typically these commands must be run as root or through sudo.)
+
+Add /usr/local/go/bin to the PATH environment variable. You can do this by adding this line to your /etc/profile (for a system-wide installation) or $HOME/.profile:
+
+export PATH=$PATH:/usr/local/go/bin
+Note: changes made to a profile file may not apply until the next time you log into your computer. To apply the changes immediately, just run the shell commands directly or execute them from the profile using a command such as source $HOME/.profile.
+
+macOS package installer
+Download the package file, open it, and follow the prompts to install the Go tools. The package installs the Go distribution to /usr/local/go.
+
+The package should put the /usr/local/go/bin directory in your PATH environment variable. You may need to restart any open Terminal sessions for the change to take effect.
+
+Windows
+The Go project provides two installation options for Windows users (besides installing from source): a zip archive that requires you to set some environment variables and an MSI installer that configures your installation automatically.
+
+MSI installer
+Open the MSI file and follow the prompts to install the Go tools. By default, the installer puts the Go distribution in c:\Go.
+
+The installer should put the c:\Go\bin directory in your PATH environment variable. You may need to restart any open command prompts for the change to take effect.
+
+Zip archive
+Download the zip file and extract it into the directory of your choice (we suggest c:\Go).
+
+Add the bin subdirectory of your Go root (for example, c:\Go\bin) to your PATH environment variable.
+
+Setting environment variables under Windows
+Under Windows, you may set environment variables through the "Environment Variables" button on the "Advanced" tab of the "System" control panel. Some versions of Windows provide this control panel through the "Advanced System Settings" option inside the "System" control panel.
+
+Test your installation
+Check that Go is installed correctly by setting up a workspace and building a simple program, as follows.
+
+Create your workspace directory, $HOME/go. (If you'd like to use a different directory, you will need to set the GOPATH environment variable.)
+
+Next, make the directory src/hello inside your workspace, and in that directory create a file named hello.go that looks like:
+
+package main
+
+import "fmt"
+
+func main() {
+	fmt.Printf("hello, world\n")
+}
+Then build it with the go tool:
+
+$ cd $HOME/go/src/hello
+$ go build
+The command above will build an executable named hello in the directory alongside your source code. Execute it to see the greeting:
+
+$ ./hello
+hello, world
+If you see the "hello, world" message then your Go installation is working.
+
+You can run go install to install the binary into your workspace's bin directory or go clean -i to remove it.
+
+Before rushing off to write Go code please read the How to Write Go Code document, which describes some essential concepts about using the Go tools.
+
+Installing extra Go versions
+It may be useful to have multiple Go versions installed on the same machine, for example, to ensure that a package's tests pass on multiple Go versions. Once you have one Go version installed, you can install another (such as 1.10.7) as follows:
+
+$ go get golang.org/dl/go1.10.7
+$ go1.10.7 download
+The newly downloaded version can be used like go:
+
+$ go1.10.7 version
+go version go1.10.7 linux/amd64
+All Go versions available via this method are listed on the download page. You can find where each of these extra Go versions is installed by looking at its GOROOT; for example, go1.10.7 env GOROOT. To uninstall a downloaded version, just remove its GOROOT directory and the goX.Y.Z binary.
+
+Uninstalling Go
+To remove an existing Go installation from your system delete the go directory. This is usually /usr/local/go under Linux, macOS, and FreeBSD or c:\Go under Windows.
+
+You should also remove the Go bin directory from your PATH environment variable. Under Linux and FreeBSD you should edit /etc/profile or $HOME/.profile. If you installed Go with the macOS package then you should remove the /etc/paths.d/go file. Windows users should read the section about setting environment variables under Windows.
+
+Getting help
+For help, see the list of Go mailing lists, forums, and places to chat.
+
+Report bugs either by running “go bug”, or manually at the Go issue tracker.
+
+The Go Gopher
+Copyright Terms of Service Privacy Policy Report a website issue
+Supported by Google

hw07_file_copying/testdata/out_offset0_limit0.txt

@@ -0,0 +1,125 @@
+Go
+Documents
+Packages
+The Project
+Help
+Blog
+Play
+Search
+
+Getting Started
+Install the Go tools
+Test your installation
+Installing extra Go versions
+Uninstalling Go
+Getting help
+Download the Go distribution
+Download Go
+Click here to visit the downloads page
+Official binary distributions are available for the FreeBSD (release 10-STABLE and above), Linux, macOS (10.10 and above), and Windows operating systems and the 32-bit (386) and 64-bit (amd64) x86 processor architectures.
+
+If a binary distribution is not available for your combination of operating system and architecture, try installing from source or installing gccgo instead of gc.
+
+System requirements
+Go binary distributions are available for these supported operating systems and architectures. Please ensure your system meets these requirements before proceeding. If your OS or architecture is not on the list, you may be able to install from source or use gccgo instead.
+
+Operating system	Architectures	Notes
+FreeBSD 10.3 or later	amd64, 386	Debian GNU/kFreeBSD not supported
+Linux 2.6.23 or later with glibc	amd64, 386, arm, arm64,
+s390x, ppc64le	CentOS/RHEL 5.x not supported.
+Install from source for other libc.
+macOS 10.10 or later	amd64	use the clang or gcc† that comes with Xcode‡ for cgo support
+Windows 7, Server 2008R2 or later	amd64, 386	use MinGW (386) or MinGW-W64 (amd64) gcc†.
+No need for cygwin or msys.
+†A C compiler is required only if you plan to use cgo.
+‡You only need to install the command line tools for Xcode. If you have already installed Xcode 4.3+, you can install it from the Components tab of the Downloads preferences panel.
+
+Install the Go tools
+If you are upgrading from an older version of Go you must first remove the existing version.
+
+Linux, macOS, and FreeBSD tarballs
+Download the archive and extract it into /usr/local, creating a Go tree in /usr/local/go. For example:
+
+tar -C /usr/local -xzf go$VERSION.$OS-$ARCH.tar.gz
+Choose the archive file appropriate for your installation. For instance, if you are installing Go version 1.2.1 for 64-bit x86 on Linux, the archive you want is called go1.2.1.linux-amd64.tar.gz.
+
+(Typically these commands must be run as root or through sudo.)
+
+Add /usr/local/go/bin to the PATH environment variable. You can do this by adding this line to your /etc/profile (for a system-wide installation) or $HOME/.profile:
+
+export PATH=$PATH:/usr/local/go/bin
+Note: changes made to a profile file may not apply until the next time you log into your computer. To apply the changes immediately, just run the shell commands directly or execute them from the profile using a command such as source $HOME/.profile.
+
+macOS package installer
+Download the package file, open it, and follow the prompts to install the Go tools. The package installs the Go distribution to /usr/local/go.
+
+The package should put the /usr/local/go/bin directory in your PATH environment variable. You may need to restart any open Terminal sessions for the change to take effect.
+
+Windows
+The Go project provides two installation options for Windows users (besides installing from source): a zip archive that requires you to set some environment variables and an MSI installer that configures your installation automatically.
+
+MSI installer
+Open the MSI file and follow the prompts to install the Go tools. By default, the installer puts the Go distribution in c:\Go.
+
+The installer should put the c:\Go\bin directory in your PATH environment variable. You may need to restart any open command prompts for the change to take effect.
+
+Zip archive
+Download the zip file and extract it into the directory of your choice (we suggest c:\Go).
+
+Add the bin subdirectory of your Go root (for example, c:\Go\bin) to your PATH environment variable.
+
+Setting environment variables under Windows
+Under Windows, you may set environment variables through the "Environment Variables" button on the "Advanced" tab of the "System" control panel. Some versions of Windows provide this control panel through the "Advanced System Settings" option inside the "System" control panel.
+
+Test your installation
+Check that Go is installed correctly by setting up a workspace and building a simple program, as follows.
+
+Create your workspace directory, $HOME/go. (If you'd like to use a different directory, you will need to set the GOPATH environment variable.)
+
+Next, make the directory src/hello inside your workspace, and in that directory create a file named hello.go that looks like:
+
+package main
+
+import "fmt"
+
+func main() {
+	fmt.Printf("hello, world\n")
+}
+Then build it with the go tool:
+
+$ cd $HOME/go/src/hello
+$ go build
+The command above will build an executable named hello in the directory alongside your source code. Execute it to see the greeting:
+
+$ ./hello
+hello, world
+If you see the "hello, world" message then your Go installation is working.
+
+You can run go install to install the binary into your workspace's bin directory or go clean -i to remove it.
+
+Before rushing off to write Go code please read the How to Write Go Code document, which describes some essential concepts about using the Go tools.
+
+Installing extra Go versions
+It may be useful to have multiple Go versions installed on the same machine, for example, to ensure that a package's tests pass on multiple Go versions. Once you have one Go version installed, you can install another (such as 1.10.7) as follows:
+
+$ go get golang.org/dl/go1.10.7
+$ go1.10.7 download
+The newly downloaded version can be used like go:
+
+$ go1.10.7 version
+go version go1.10.7 linux/amd64
+All Go versions available via this method are listed on the download page. You can find where each of these extra Go versions is installed by looking at its GOROOT; for example, go1.10.7 env GOROOT. To uninstall a downloaded version, just remove its GOROOT directory and the goX.Y.Z binary.
+
+Uninstalling Go
+To remove an existing Go installation from your system delete the go directory. This is usually /usr/local/go under Linux, macOS, and FreeBSD or c:\Go under Windows.
+
+You should also remove the Go bin directory from your PATH environment variable. Under Linux and FreeBSD you should edit /etc/profile or $HOME/.profile. If you installed Go with the macOS package then you should remove the /etc/paths.d/go file. Windows users should read the section about setting environment variables under Windows.
+
+Getting help
+For help, see the list of Go mailing lists, forums, and places to chat.
+
+Report bugs either by running “go bug”, or manually at the Go issue tracker.
+
+The Go Gopher
+Copyright Terms of Service Privacy Policy Report a website issue
+Supported by Google

hw07_file_copying/testdata/out_offset0_limit10.txt

@@ -0,0 +1,2 @@
+Go
+Documen

hw07_file_copying/testdata/out_offset0_limit1000.txt

@@ -0,0 +1,27 @@
+Go
+Documents
+Packages
+The Project
+Help
+Blog
+Play
+Search
+
+Getting Started
+Install the Go tools
+Test your installation
+Installing extra Go versions
+Uninstalling Go
+Getting help
+Download the Go distribution
+Download Go
+Click here to visit the downloads page
+Official binary distributions are available for the FreeBSD (release 10-STABLE and above), Linux, macOS (10.10 and above), and Windows operating systems and the 32-bit (386) and 64-bit (amd64) x86 processor architectures.
+
+If a binary distribution is not available for your combination of operating system and architecture, try installing from source or installing gccgo instead of gc.
+
+System requirements
+Go binary distributions are available for these supported operating systems and architectures. Please ensure your system meets these requirements before proceeding. If your OS or architecture is not on the list, you may be able to install from source or use gccgo instead.
+
+Operating system	Architectures	Notes
+FreeBSD 10.3 or later	amd64

hw07_file_copying/testdata/out_offset0_limit10000.txt

@@ -0,0 +1,125 @@
+Go
+Documents
+Packages
+The Project
+Help
+Blog
+Play
+Search
+
+Getting Started
+Install the Go tools
+Test your installation
+Installing extra Go versions
+Uninstalling Go
+Getting help
+Download the Go distribution
+Download Go
+Click here to visit the downloads page
+Official binary distributions are available for the FreeBSD (release 10-STABLE and above), Linux, macOS (10.10 and above), and Windows operating systems and the 32-bit (386) and 64-bit (amd64) x86 processor architectures.
+
+If a binary distribution is not available for your combination of operating system and architecture, try installing from source or installing gccgo instead of gc.
+
+System requirements
+Go binary distributions are available for these supported operating systems and architectures. Please ensure your system meets these requirements before proceeding. If your OS or architecture is not on the list, you may be able to install from source or use gccgo instead.
+
+Operating system	Architectures	Notes
+FreeBSD 10.3 or later	amd64, 386	Debian GNU/kFreeBSD not supported
+Linux 2.6.23 or later with glibc	amd64, 386, arm, arm64,
+s390x, ppc64le	CentOS/RHEL 5.x not supported.
+Install from source for other libc.
+macOS 10.10 or later	amd64	use the clang or gcc† that comes with Xcode‡ for cgo support
+Windows 7, Server 2008R2 or later	amd64, 386	use MinGW (386) or MinGW-W64 (amd64) gcc†.
+No need for cygwin or msys.
+†A C compiler is required only if you plan to use cgo.
+‡You only need to install the command line tools for Xcode. If you have already installed Xcode 4.3+, you can install it from the Components tab of the Downloads preferences panel.
+
+Install the Go tools
+If you are upgrading from an older version of Go you must first remove the existing version.
+
+Linux, macOS, and FreeBSD tarballs
+Download the archive and extract it into /usr/local, creating a Go tree in /usr/local/go. For example:
+
+tar -C /usr/local -xzf go$VERSION.$OS-$ARCH.tar.gz
+Choose the archive file appropriate for your installation. For instance, if you are installing Go version 1.2.1 for 64-bit x86 on Linux, the archive you want is called go1.2.1.linux-amd64.tar.gz.
+
+(Typically these commands must be run as root or through sudo.)
+
+Add /usr/local/go/bin to the PATH environment variable. You can do this by adding this line to your /etc/profile (for a system-wide installation) or $HOME/.profile:
+
+export PATH=$PATH:/usr/local/go/bin
+Note: changes made to a profile file may not apply until the next time you log into your computer. To apply the changes immediately, just run the shell commands directly or execute them from the profile using a command such as source $HOME/.profile.
+
+macOS package installer
+Download the package file, open it, and follow the prompts to install the Go tools. The package installs the Go distribution to /usr/local/go.
+
+The package should put the /usr/local/go/bin directory in your PATH environment variable. You may need to restart any open Terminal sessions for the change to take effect.
+
+Windows
+The Go project provides two installation options for Windows users (besides installing from source): a zip archive that requires you to set some environment variables and an MSI installer that configures your installation automatically.
+
+MSI installer
+Open the MSI file and follow the prompts to install the Go tools. By default, the installer puts the Go distribution in c:\Go.
+
+The installer should put the c:\Go\bin directory in your PATH environment variable. You may need to restart any open command prompts for the change to take effect.
+
+Zip archive
+Download the zip file and extract it into the directory of your choice (we suggest c:\Go).
+
+Add the bin subdirectory of your Go root (for example, c:\Go\bin) to your PATH environment variable.
+
+Setting environment variables under Windows
+Under Windows, you may set environment variables through the "Environment Variables" button on the "Advanced" tab of the "System" control panel. Some versions of Windows provide this control panel through the "Advanced System Settings" option inside the "System" control panel.
+
+Test your installation
+Check that Go is installed correctly by setting up a workspace and building a simple program, as follows.
+
+Create your workspace directory, $HOME/go. (If you'd like to use a different directory, you will need to set the GOPATH environment variable.)
+
+Next, make the directory src/hello inside your workspace, and in that directory create a file named hello.go that looks like:
+
+package main
+
+import "fmt"
+
+func main() {
+	fmt.Printf("hello, world\n")
+}
+Then build it with the go tool:
+
+$ cd $HOME/go/src/hello
+$ go build
+The command above will build an executable named hello in the directory alongside your source code. Execute it to see the greeting:
+
+$ ./hello
+hello, world
+If you see the "hello, world" message then your Go installation is working.
+
+You can run go install to install the binary into your workspace's bin directory or go clean -i to remove it.
+
+Before rushing off to write Go code please read the How to Write Go Code document, which describes some essential concepts about using the Go tools.
+
+Installing extra Go versions
+It may be useful to have multiple Go versions installed on the same machine, for example, to ensure that a package's tests pass on multiple Go versions. Once you have one Go version installed, you can install another (such as 1.10.7) as follows:
+
+$ go get golang.org/dl/go1.10.7
+$ go1.10.7 download
+The newly downloaded version can be used like go:
+
+$ go1.10.7 version
+go version go1.10.7 linux/amd64
+All Go versions available via this method are listed on the download page. You can find where each of these extra Go versions is installed by looking at its GOROOT; for example, go1.10.7 env GOROOT. To uninstall a downloaded version, just remove its GOROOT directory and the goX.Y.Z binary.
+
+Uninstalling Go
+To remove an existing Go installation from your system delete the go directory. This is usually /usr/local/go under Linux, macOS, and FreeBSD or c:\Go under Windows.
+
+You should also remove the Go bin directory from your PATH environment variable. Under Linux and FreeBSD you should edit /etc/profile or $HOME/.profile. If you installed Go with the macOS package then you should remove the /etc/paths.d/go file. Windows users should read the section about setting environment variables under Windows.
+
+Getting help
+For help, see the list of Go mailing lists, forums, and places to chat.
+
+Report bugs either by running “go bug”, or manually at the Go issue tracker.
+
+The Go Gopher
+Copyright Terms of Service Privacy Policy Report a website issue
+Supported by Google

hw07_file_copying/testdata/out_offset100_limit1000.txt

@@ -0,0 +1,18 @@
+our installation
+Installing extra Go versions
+Uninstalling Go
+Getting help
+Download the Go distribution
+Download Go
+Click here to visit the downloads page
+Official binary distributions are available for the FreeBSD (release 10-STABLE and above), Linux, macOS (10.10 and above), and Windows operating systems and the 32-bit (386) and 64-bit (amd64) x86 processor architectures.
+
+If a binary distribution is not available for your combination of operating system and architecture, try installing from source or installing gccgo instead of gc.
+
+System requirements
+Go binary distributions are available for these supported operating systems and architectures. Please ensure your system meets these requirements before proceeding. If your OS or architecture is not on the list, you may be able to install from source or use gccgo instead.
+
+Operating system	Architectures	Notes
+FreeBSD 10.3 or later	amd64, 386	Debian GNU/kFreeBSD not supported
+Linux 2.6.23 or later with glibc	amd64, 386, arm, arm64,
+s39

hw07_file_copying/testdata/out_offset6000_limit1000.txt

@@ -0,0 +1,12 @@
+nder Windows.
+
+You should also remove the Go bin directory from your PATH environment variable. Under Linux and FreeBSD you should edit /etc/profile or $HOME/.profile. If you installed Go with the macOS package then you should remove the /etc/paths.d/go file. Windows users should read the section about setting environment variables under Windows.
+
+Getting help
+For help, see the list of Go mailing lists, forums, and places to chat.
+
+Report bugs either by running “go bug”, or manually at the Go issue tracker.
+
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