csv-parser/csv-parser.go

92 lines
1.8 KiB
Go

package csvparser
import (
"strings"
"errors"
)
type EncloserId int
const (
None EncloserId = iota
DoubleQuotes
SingleQuotes
RoundBrackets
SquareBrackets
CurlyBrackets
)
type Encloser struct {
Open byte
Close byte
}
var EnclosersRunes = map[EncloserId]Encloser{
DoubleQuotes: Encloser{'"', '"'},
SingleQuotes: Encloser{'\'', '\''},
RoundBrackets: Encloser{'(', ')'},
SquareBrackets: Encloser{'[', ']'},
CurlyBrackets: Encloser{'{', '}'},
}
type CsvParser struct {
Enclosers []EncloserId
Delimiter string
Fields []string
Line string
}
func (parser *CsvParser) Init() {
parser.Enclosers = []EncloserId{DoubleQuotes, SquareBrackets}
parser.Delimiter = " \t"
}
func (parser *CsvParser) ExtractEnclosedFieldValue(line string, endChar byte) (string, error) {
lineLen := len(line)
for i := 1; i < lineLen; i++ {
if line[i] == endChar && line[i-1] != '\\' {
parser.Fields = append(parser.Fields, line[1:i])
return line[i+1:], nil
}
}
return line, errors.New("Encloser close not found")
}
func (parser *CsvParser) Parse(line string) error {
var err error = nil
for len(line) > 0 {
line = strings.TrimLeft(line, parser.Delimiter)
line = strings.TrimRight(line, parser.Delimiter)
if len(line) == 0 {
break
}
// Search for an encloser
encloserId := None
for _, id := range parser.Enclosers {
if line[0] == EnclosersRunes[id].Open {
encloserId = id
break
}
}
if encloserId != None {
line, err = parser.ExtractEnclosedFieldValue(line, EnclosersRunes[encloserId].Close)
if err != nil {
return err
}
} else {
nextSpace := strings.IndexAny(line, parser.Delimiter)
if nextSpace != -1 {
parser.Fields = append(parser.Fields, line[:nextSpace])
line = line[nextSpace:]
} else {
parser.Fields = append(parser.Fields, line)
line = ""
break
}
}
}
return nil
}