84 lines
1.6 KiB
Go
84 lines
1.6 KiB
Go
package eol
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import (
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"io"
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)
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// ReadEOL tries to read and end-of-line character.
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//
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// The end-of-line sequences it supports are:
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//
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// line-feed (LF) (U+000A) ('\n')
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// carriage-return (CR) (U+000D) ('\r')
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// carriage-return, line-feed ("\r\n")
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// next-line (NEL) (U+0085)
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// line-separator (LS) (U+2028)
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//
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// If successful, ReadEOL return the end-of-line sequence and the number-of-bytes read.
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func ReadEOL(runescanner io.RuneScanner) (endofline string, size int, err error) {
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if nil == runescanner {
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return "", 0, errNilRuneScanner
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}
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var r0 rune
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var size0 int
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{
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var err error
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r0, size0, err = runescanner.ReadRune()
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if nil != err {
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const runeNumber = 1
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return "", size0, errProblemReadingRune(err, runeNumber)
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}
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}
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switch r0 {
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case lf:
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return LF, size0, nil
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case cr:
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// Nothing here.
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case nel:
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return NEL, size0, nil
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case ls:
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return LS, size0, nil
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default:
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err := runescanner.UnreadRune()
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if nil != err {
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const runeNumber = 1
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return "", size0, errProblemUnreadingRune(err, runeNumber, r0)
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}
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return "", 0, errNotEOL(r0)
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}
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// if we got here, then we had a CR
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var r1 rune
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var size1 int
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{
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var err error
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r1, size1, err = runescanner.ReadRune()
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if io.EOF == err {
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return CR, size0, nil
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}
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if nil != err {
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const runeNumber = 2
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return "", size1+size0, errProblemReadingRune(err, runeNumber)
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}
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}
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switch r1 {
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case lf:
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return CRLF, size1+size0, nil
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default:
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err := runescanner.UnreadRune()
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if nil != err {
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const runeNumber = 2
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return "", size1+size0, errProblemUnreadingRune(err, runeNumber, r1)
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}
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return CR, size0, nil
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}
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}
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