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