123 lines
3.5 KiB
Go
123 lines
3.5 KiB
Go
/*
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Copyright 2019 Drew DeVault <sir@cmpwn.com>
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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1. Redistributions of source code must retain the above copyright notice, this
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list of conditions and the following disclaimer.
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2. Redistributions in binary form must reproduce the above copyright notice,
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this list of conditions and the following disclaimer in the documentation
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and/or other materials provided with the distribution.
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3. Neither the name of the copyright holder nor the names of its contributors
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may be used to endorse or promote products derived from this software without
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specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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package util
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import (
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"fmt"
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"os"
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)
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// In the case of "-o example", Option is 'o' and "example" is Value. For
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// options which do not take an argument, Value is "".
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type Option struct {
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Option rune
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Value string
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}
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// This is returned when an unknown option is found in argv, but not in the
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// option spec.
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type UnknownOptionError rune
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func (e UnknownOptionError) Error() string {
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return fmt.Sprintf("%s: unknown option -%c", os.Args[0], rune(e))
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}
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// This is returned when an option with a mandatory argument is missing that
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// argument.
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type MissingOptionError rune
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func (e MissingOptionError) Error() string {
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return fmt.Sprintf("%s: expected argument for -%c", os.Args[0], rune(e))
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}
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// Getopts implements a POSIX-compatible options interface.
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//
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// Returns a slice of options and the index of the first non-option argument.
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//
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// If an error is returned, you must print it to stderr to be POSIX complaint.
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func Getopts(argv []string, spec string) ([]Option, int, error) {
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optmap := make(map[rune]bool)
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runes := []rune(spec)
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for i, rn := range spec {
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if rn == ':' {
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if i == 0 {
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continue
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}
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optmap[runes[i-1]] = true
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} else {
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optmap[rn] = false
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}
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}
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var (
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i int
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opts []Option
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)
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for i = 1; i < len(argv); i++ {
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arg := argv[i]
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runes = []rune(arg)
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if len(arg) == 0 || arg == "-" {
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break
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}
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if arg[0] != '-' {
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break
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}
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if arg == "--" {
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i++
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break
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}
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for j, opt := range runes[1:] {
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if optopt, ok := optmap[opt]; !ok {
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opts = append(opts, Option{'?', ""})
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return opts, i, UnknownOptionError(opt)
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} else if optopt {
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if j+1 < len(runes)-1 {
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opts = append(opts, Option{opt, string(runes[j+2:])})
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break
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} else {
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if i+1 >= len(argv) {
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if len(spec) >= 1 && spec[0] == ':' {
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opts = append(opts, Option{':', string(opt)})
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} else {
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return opts, i, MissingOptionError(opt)
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}
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} else {
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opts = append(opts, Option{opt, argv[i+1]})
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i++
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}
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}
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} else {
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opts = append(opts, Option{opt, ""})
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}
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}
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}
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return opts, i, nil
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}
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