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go-mtree/pkg/govis/govis.go
Aleksa Sarai 3ce83fca15
govis: add SPDX license tag
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
2025-09-23 04:14:37 +10:00

82 lines
2.7 KiB
Go

// SPDX-License-Identifier: Apache-2.0
/*
* govis: unicode aware vis(3) encoding implementation
* Copyright (C) 2017-2025 SUSE LLC.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package govis
import (
"strconv"
"strings"
)
// VisFlag manipulates how the characters are encoded/decoded
type VisFlag uint
// vis() has a variety of flags when deciding what encodings to use. While
// mtree only uses one set of flags, implementing them all is necessary in
// order to have compatibility with BSD's vis() and unvis() commands.
const (
VisOctal VisFlag = (1 << iota) // VIS_OCTAL: Use octal \ddd format.
VisCStyle // VIS_CSTYLE: Use \[nrft0..] where appropriate.
VisSpace // VIS_SP: Also encode space.
VisTab // VIS_TAB: Also encode tab.
VisNewline // VIS_NL: Also encode newline.
VisSafe // VIS_SAFE: Encode unsafe characters.
VisNoSlash // VIS_NOSLASH: Inhibit printing '\'.
VisHTTPStyle // VIS_HTTPSTYLE: HTTP-style escape %xx.
VisGlob // VIS_GLOB: Encode glob(3) magics.
visMask VisFlag = (1 << iota) - 1 // Mask of all flags.
VisWhite VisFlag = (VisSpace | VisTab | VisNewline)
)
// String pretty-prints VisFlag.
func (vflags VisFlag) String() string {
flagNames := []struct {
name string
bits VisFlag
}{
{"VisOctal", VisOctal},
{"VisCStyle", VisCStyle},
{"VisSpace", VisSpace},
{"VisTab", VisTab},
{"VisNewline", VisNewline},
{"VisSafe", VisSafe},
{"VisNoSlash", VisNoSlash},
{"VisHTTPStyle", VisHTTPStyle},
{"VisGlob", VisGlob},
}
var (
flagSet = make([]string, 0, len(flagNames))
seenBits VisFlag
)
for _, flag := range flagNames {
if vflags&flag.bits == flag.bits {
seenBits |= flag.bits
flagSet = append(flagSet, flag.name)
}
}
// If there were any remaining flags specified we don't know the name of,
// just add them in an 0x... format.
if remaining := vflags &^ seenBits; remaining != 0 {
flagSet = append(flagSet, "0x"+strconv.FormatUint(uint64(remaining), 16))
}
if len(flagSet) == 0 {
return "0"
}
return strings.Join(flagSet, "|")
}