99 lines
2.0 KiB
Go
99 lines
2.0 KiB
Go
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// Copyright 2015 Jean Niklas L'orange. 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 edn
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import (
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"bytes"
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"io"
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)
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func tokNeedsDelim(t tokenType) bool {
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switch t {
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case tokenString, tokenListStart, tokenListEnd, tokenVectorStart,
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tokenVectorEnd, tokenMapEnd, tokenMapStart, tokenSetStart, tokenDiscard, tokenError:
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return false
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}
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return true
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}
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func delimits(r rune) bool {
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switch r {
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case '{', '}', '[', ']', '(', ')', '\\', '"':
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return true
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}
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return isWhitespace(r)
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}
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// Compact appends to dst a compacted form of the EDN-encoded src. It does not
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// remove discard values.
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func Compact(dst *bytes.Buffer, src []byte) error {
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origLen := dst.Len()
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var lex lexer
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lex.reset()
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buf := bytes.NewBuffer(src)
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start, pos := 0, 0
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needsDelim := false
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prevIgnore := '\uFFFD'
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r, size, err := buf.ReadRune()
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for ; err == nil; r, size, err = buf.ReadRune() {
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ls := lex.state(r)
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ppos := pos
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pos += size
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switch ls {
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case lexCont:
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if ppos == start && needsDelim && !delimits(r) {
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dst.WriteRune(prevIgnore)
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}
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continue
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case lexIgnore:
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prevIgnore = r
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start = pos
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case lexError:
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dst.Truncate(origLen)
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return lex.err
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case lexEnd:
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// here we might want to discard #_ and the like. Currently we don't.
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dst.Write(src[start:pos])
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needsDelim = tokNeedsDelim(lex.token)
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lex.reset()
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start = pos
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case lexEndPrev:
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dst.Write(src[start:ppos])
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lex.reset()
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lss := lex.state(r)
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needsDelim = tokNeedsDelim(lex.token)
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switch lss {
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case lexIgnore:
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prevIgnore = r
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start = pos
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case lexCont:
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start = ppos
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case lexEnd:
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dst.WriteRune(r)
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lex.reset()
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start = pos
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case lexEndPrev:
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dst.Truncate(origLen)
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return errInternal
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case lexError:
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dst.Truncate(origLen)
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return lex.err
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}
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}
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}
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if err != io.EOF {
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return err
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}
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ls := lex.eof()
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switch ls {
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case lexEnd:
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dst.Write(src[start:pos])
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case lexError:
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dst.Truncate(origLen)
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return lex.err
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}
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return nil
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}
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