podman

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// Copyright 2018 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package json
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import (
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	"strconv"
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	"unicode"
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	"unicode/utf16"
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	"unicode/utf8"
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	"google.golang.org/protobuf/internal/strs"
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)
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func (d *Decoder) parseString(in []byte) (string, int, error) {
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	in0 := in
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	if len(in) == 0 {
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		return "", 0, ErrUnexpectedEOF
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	}
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	if in[0] != '"' {
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		return "", 0, d.newSyntaxError(d.currPos(), "invalid character %q at start of string", in[0])
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	}
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	in = in[1:]
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	i := indexNeedEscapeInBytes(in)
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	in, out := in[i:], in[:i:i] // set cap to prevent mutations
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	for len(in) > 0 {
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		switch r, n := utf8.DecodeRune(in); {
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		case r == utf8.RuneError && n == 1:
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			return "", 0, d.newSyntaxError(d.currPos(), "invalid UTF-8 in string")
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		case r < ' ':
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			return "", 0, d.newSyntaxError(d.currPos(), "invalid character %q in string", r)
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		case r == '"':
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			in = in[1:]
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			n := len(in0) - len(in)
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			return string(out), n, nil
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		case r == '\\':
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			if len(in) < 2 {
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				return "", 0, ErrUnexpectedEOF
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			}
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			switch r := in[1]; r {
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			case '"', '\\', '/':
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				in, out = in[2:], append(out, r)
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			case 'b':
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				in, out = in[2:], append(out, '\b')
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			case 'f':
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				in, out = in[2:], append(out, '\f')
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			case 'n':
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				in, out = in[2:], append(out, '\n')
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			case 'r':
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				in, out = in[2:], append(out, '\r')
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			case 't':
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				in, out = in[2:], append(out, '\t')
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			case 'u':
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				if len(in) < 6 {
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					return "", 0, ErrUnexpectedEOF
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				}
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				v, err := strconv.ParseUint(string(in[2:6]), 16, 16)
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				if err != nil {
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					return "", 0, d.newSyntaxError(d.currPos(), "invalid escape code %q in string", in[:6])
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				}
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				in = in[6:]
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				r := rune(v)
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				if utf16.IsSurrogate(r) {
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					if len(in) < 6 {
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						return "", 0, ErrUnexpectedEOF
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					}
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					v, err := strconv.ParseUint(string(in[2:6]), 16, 16)
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					r = utf16.DecodeRune(r, rune(v))
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					if in[0] != '\\' || in[1] != 'u' ||
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						r == unicode.ReplacementChar || err != nil {
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						return "", 0, d.newSyntaxError(d.currPos(), "invalid escape code %q in string", in[:6])
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					}
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					in = in[6:]
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				}
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				out = append(out, string(r)...)
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			default:
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				return "", 0, d.newSyntaxError(d.currPos(), "invalid escape code %q in string", in[:2])
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			}
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		default:
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			i := indexNeedEscapeInBytes(in[n:])
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			in, out = in[n+i:], append(out, in[:n+i]...)
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		}
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	}
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	return "", 0, ErrUnexpectedEOF
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}
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// indexNeedEscapeInBytes returns the index of the character that needs
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// escaping. If no characters need escaping, this returns the input length.
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func indexNeedEscapeInBytes(b []byte) int { return indexNeedEscapeInString(strs.UnsafeString(b)) }
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