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sanitizer.go
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/
sanitizer.go
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package main
import (
"bufio"
"bytes"
"io"
"regexp"
"strings"
)
//var sanitizeTable = map[string]string{
// "\r": "",
// "\n\n": "\n",
// "\\n": "\n",
// " :": ":",
// "\t": " ",
//}
var encodingTable = map[string]string{
"€": "€",
"‚": "‚",
"Æ’": "ƒ",
"„": "„",
"…": "…",
"‡": "‡",
"ˆ": "ˆ",
"‰": "‰",
"‹": "‹",
"Å’": "Œ",
"Ž": "Ž",
"‘": "‘",
"’": "’",
"“": "“",
"•": "•",
"–": "–",
"—": "—",
"Ëœ": "˜",
"â„¢": "™",
"Å¡": "š",
"›": "›",
"Å“": "œ",
"ž": "ž",
"Ÿ": "Ÿ",
"¡": "¡",
"¢": "¢",
"£": "£",
"¤": "¤",
"Â¥": "¥",
"¦": "¦",
"§": "§",
"¨": "¨",
"©": "©",
"ª": "ª",
"«": "«",
"®": "®",
"¯": "¯",
"°": "°",
"±": "±",
"²": "²",
"³": "³",
"´": "´",
"µ": "µ",
"¶": "¶",
"·": "·",
"¸": "¸",
"¹": "¹",
"º": "º",
"»": "»",
"¼": "¼",
"½": "½",
"¾": "¾",
"¿": "¿",
"À": "À",
"Â": "Â",
"Ã": "Ã",
"Ä": "Ä",
"Ã…": "Å",
"Æ": "Æ",
"Ç": "Ç",
"È": "È",
"É": "É",
"Ê": "Ê",
"Ë": "Ë",
"ÃŒ": "Ì",
"ÃŽ": "Î",
"Ñ": "Ñ",
"Ã’": "Ò",
"Ó": "Ó",
"Ô": "Ô",
"Õ": "Õ",
"Ö": "Ö",
"×": "×",
"Ø": "Ø",
"Ù": "Ù",
"Ú": "Ú",
"Û": "Û",
"Ãœ": "Ü",
"Þ": "Þ",
"ß": "ß",
"á": "á",
"â": "â",
"ã": "ã",
"ä": "ä",
"Ã¥": "å",
"æ": "æ",
"ç": "ç",
"è": "è",
"é": "é",
"ê": "ê",
"ë": "ë",
"ì": "ì",
"î": "î",
"ï": "ï",
"ð": "ð",
"ñ": "ñ",
"ò": "ò",
"ó": "ó",
"ô": "ô",
"õ": "õ",
"ö": "ö",
"÷": "÷",
"ø": "ø",
"ù": "ù",
"ú": "ú",
"û": "û",
"ü": "ü",
"ý": "ý",
"þ": "þ",
"ÿ": "ÿ",
}
// SanitizedRuneReader
// SanitizeRuneReader sanitizes the runes from an io.RuneReader, removing
// extra whitespace, and replacing escaped newlines with actual newlines, and
// replacing tabs with spaces.
type SanitizedRuneReader struct {
bufSize int
lastRune *rune
whitespaceRegex *regexp.Regexp
reader *bufio.Reader
currBuffer **bytes.Buffer
accumulator *[]rune
accumulatorIdx *int
moreBuffers chan *bytes.Buffer
}
// nextBuffer accumulates sanitized runes into a buffer, and returns the buffer.
func (runeReader SanitizedRuneReader) nextBuffer() *bytes.Buffer {
acc := runeReader.accumulator
accIdx := runeReader.accumulatorIdx
idx := *accIdx
var text string
for {
if idx > runeReader.bufSize {
text = string((*acc)[:runeReader.bufSize])
(*acc)[0] = (*acc)[idx-1]
*accIdx = 1
break
}
r, size, _ := (*runeReader.reader).ReadRune()
if size == 0 && idx == 0 {
// No valid rune, and our accumulator is empty, so we're done.
return nil
} else if size == 0 {
// No valid rune, and we have stuff in our accumulator, so let's
// flush and finish up.
text = string((*acc)[:idx])
*accIdx = 0
break
} else if r == '\r' {
// Silently drop Windows `\r`
} else if r == '\n' && *runeReader.lastRune == '\n' {
// Drop additional newlines.
} else if r == 'n' && *runeReader.lastRune == '\\' {
// Replace escaped `\n` with `\n`.
(*acc)[idx-1] = '\n'
} else if r == ':' && *runeReader.lastRune == ' ' {
// Strip colons with leading spaces.
(*acc)[idx-1] = ':'
} else if r == '\t' {
// Replace tabs with single spaces.
(*acc)[idx] = ' '
idx++
} else {
// We have a valid rune, so let's insert it onto our accumulator.
(*acc)[idx] = r
idx++
}
if idx == 0 {
*runeReader.lastRune = ' '
} else {
*runeReader.lastRune = (*acc)[idx-1]
}
}
lines := strings.Split(text, "\n")
for lineIdx := range lines {
line := lines[lineIdx]
line = runeReader.whitespaceRegex.ReplaceAllString(line, " ")
line = strings.TrimSpace(line)
lines[lineIdx] = line
}
text = strings.Join(lines, "\n")
stringBuffer := bytes.NewBufferString(text)
return stringBuffer
}
// ReadRune implements the bytes.RuneReader interface. It returns the next rune
// from the sanitized reader, along with the size of the rune, and whether or
// not there are any more runes to read.
func (runeReader SanitizedRuneReader) ReadRune() (r rune, size int,
err error) {
if *runeReader.currBuffer == nil {
return 0, 0, io.EOF
} else if r, size, err = (*runeReader.currBuffer).ReadRune(); err != nil {
if newBuffer, ok := <-runeReader.moreBuffers; !ok {
return 0, 0, io.EOF
} else {
*runeReader.currBuffer = newBuffer
return (*runeReader.currBuffer).ReadRune()
}
} else {
return r, size, err
}
}
// CreateTextSanitizer creates a SanitizedRuneReader that consumes an io.Reader
// and sanitizes the text it reads. The returned SanitizedRuneReader can be used
// to read scrubbed runes from the io.Reader.
func CreateTextSanitizer(handle io.Reader) SanitizedRuneReader {
extraWhiteSpace := regexp.MustCompile("[[:space:]]+")
scanner := bufio.NewReaderSize(handle, 8*1024*1024)
accumulator := make([]rune, 32769, 32769)
emptyBuffer := bytes.NewBufferString("")
lastRune := rune(0)
accumlatorIdx := 0
sanitizer := SanitizedRuneReader{
bufSize: 32768,
lastRune: &lastRune,
whitespaceRegex: extraWhiteSpace,
reader: scanner,
accumulator: &accumulator,
accumulatorIdx: &accumlatorIdx,
currBuffer: &emptyBuffer,
moreBuffers: make(chan *bytes.Buffer, 1),
}
nextBuffer := sanitizer.nextBuffer()
sanitizer.currBuffer = &nextBuffer
go func() {
for {
if newBuffer := sanitizer.nextBuffer(); newBuffer == nil {
close(sanitizer.moreBuffers)
break
} else {
sanitizer.moreBuffers <- newBuffer
}
}
}()
return sanitizer
}
// SanitizeText sanitizes a text file, removing extra whitespace, and replacing
// escaped newlines with actual newlines, and scrubbing colons with leading
// spaces, replacing tabs with spaces, and dropping Windows carriage returns.
func SanitizeText(text string) string {
reader := CreateTextSanitizer(bytes.NewBufferString(text))
runes := make([]rune, 0)
for {
r, size, _ := reader.ReadRune()
if size > 0 {
runes = append(runes, r)
} else {
break
}
}
return string(runes)
}