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-rw-r--r--util/getopt.go122
1 files changed, 122 insertions, 0 deletions
diff --git a/util/getopt.go b/util/getopt.go
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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
+}