/
csv.go
85 lines (77 loc) · 1.56 KB
/
csv.go
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package spreadsheet
import (
"bufio"
"encoding/csv"
"fmt"
"io"
"os"
"strings"
"unicode"
"golang.org/x/text/encoding"
"golang.org/x/text/encoding/htmlindex"
)
var EncName = "utf-8"
func init() {
EncName = os.Getenv("LANG")
if i := strings.IndexByte(EncName, '.'); i >= 0 {
EncName = strings.ToLower(EncName[i+1:])
}
if EncName == "" {
EncName = "utf-8"
}
}
func GetEncoding(encName string) (encoding.Encoding, error) {
encName = strings.ToLower(encName)
if encName == "" || encName == "utf-8" || encName == "utf8" {
return nil, nil
}
enc, err := htmlindex.Get(encName)
if err != nil {
err = fmt.Errorf("%q: %w", encName, err)
}
return enc, err
}
type csvReadCloser struct {
*csv.Reader
io.Closer
}
func OpenCsv(fn, encName string) (csvReadCloser, error) {
var enc encoding.Encoding
if encName != "" {
var err error
if enc, err = GetEncoding(encName); err != nil {
return csvReadCloser{}, err
}
}
fh := os.Stdout
if !(fn == "" || fn == "-") {
var err error
if fh, err = os.Open(fn); err != nil {
return csvReadCloser{}, err
}
}
r := io.ReadCloser(fh)
if enc != nil {
r = struct {
io.Reader
io.Closer
}{enc.NewDecoder().Reader(r), r}
}
br := bufio.NewReaderSize(r, 1<<20)
b, err := br.Peek(1024)
if err != nil && len(b) == 0 {
return csvReadCloser{}, err
}
sep := rune(',')
for _, r := range string(b) {
if r == '"' || r == '_' || unicode.IsLetter(r) || unicode.IsNumber(r) {
continue
}
sep = r
break
}
cr := csv.NewReader(br)
cr.ReuseRecord = true
cr.Comma = sep
return csvReadCloser{cr, r}, nil
}