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// Package escape contains utilities for escaping parts of InfluxQL
// and InfluxDB line protocol.
package escape // import "github.com/influxdata/influxdb/pkg/escape"
import (
"bytes"
"strings"
)
// Codes is a map of bytes to be escaped.
var Codes = map[byte][]byte{
',': []byte(`\,`),
'"': []byte(`\"`),
' ': []byte(`\ `),
'=': []byte(`\=`),
}
// Bytes escapes characters on the input slice, as defined by Codes.
func Bytes(in []byte) []byte {
for b, esc := range Codes {
in = bytes.Replace(in, []byte{b}, esc, -1)
}
return in
}
const escapeChars = `," =`
// IsEscaped returns whether b has any escaped characters,
// i.e. whether b seems to have been processed by Bytes.
func IsEscaped(b []byte) bool {
for len(b) > 0 {
i := bytes.IndexByte(b, '\\')
if i < 0 {
return false
}
if i+1 < len(b) && strings.IndexByte(escapeChars, b[i+1]) >= 0 {
return true
}
b = b[i+1:]
}
return false
}
// AppendUnescaped appends the unescaped version of src to dst
// and returns the resulting slice.
func AppendUnescaped(dst, src []byte) []byte {
var pos int
for len(src) > 0 {
next := bytes.IndexByte(src[pos:], '\\')
if next < 0 || pos+next+1 >= len(src) {
return append(dst, src...)
}
if pos+next+1 < len(src) && strings.IndexByte(escapeChars, src[pos+next+1]) >= 0 {
if pos+next > 0 {
dst = append(dst, src[:pos+next]...)
}
src = src[pos+next+1:]
pos = 0
} else {
pos += next + 1
}
}
return dst
}
// Unescape returns a new slice containing the unescaped version of in.
func Unescape(in []byte) []byte {
if len(in) == 0 {
return nil
}
if bytes.IndexByte(in, '\\') == -1 {
return in
}
i := 0
inLen := len(in)
// The output size will be no more than inLen. Preallocating the
// capacity of the output is faster and uses less memory than
// letting append() do its own (over)allocation.
out := make([]byte, 0, inLen)
for {
if i >= inLen {
break
}
if in[i] == '\\' && i+1 < inLen {
switch in[i+1] {
case ',':
out = append(out, ',')
i += 2
continue
case '"':
out = append(out, '"')
i += 2
continue
case ' ':
out = append(out, ' ')
i += 2
continue
case '=':
out = append(out, '=')
i += 2
continue
}
}
out = append(out, in[i])
i += 1
}
return out
}