nostr/wire/text/escapestring.go

57 lines
1.5 KiB
Go

package text
// EscapeString for JSON encoding according to RFC8259.
//
// taken from https://github.com/nbd-wtf/go-nostr/blob/master/utils.go replaced
// by EscapeJSONStringAndWrap in file rfc8259.go tested to be functionally
// equivalent, the purpose of the above function is to eliminate extra heap
// allocations for very long strings such as long form posts.
//
// Formatting is retained from the original despite being ugly.
func EscapeString(dst []byte, s string) []byte {
dst = append(dst, '"')
for i := 0; i < len(s); i++ {
c := s[i]
switch {
case c == '"':
// quotation mark
dst = append(dst, []byte{'\\', '"'}...)
case c == '\\':
// reverse solidus
dst = append(dst, []byte{'\\', '\\'}...)
case c >= 0x20:
// default, rest below are control chars
dst = append(dst, c)
case c == 0x08:
dst = append(dst,
[]byte{'\\', 'b'}...)
case c < 0x09:
dst = append(dst,
[]byte{'\\', 'u', '0', '0', '0', '0' + c}...)
case c == 0x09:
dst = append(dst,
[]byte{'\\', 't'}...)
case c == 0x0a:
dst = append(dst,
[]byte{'\\', 'n'}...)
case c == 0x0c:
dst = append(dst,
[]byte{'\\', 'f'}...)
case c == 0x0d:
dst = append(dst,
[]byte{'\\', 'r'}...)
case c < 0x10:
dst = append(dst,
[]byte{'\\', 'u', '0', '0', '0', 0x57 + c}...)
case c < 0x1a:
dst = append(dst,
[]byte{'\\', 'u', '0', '0', '1', 0x20 + c}...)
case c < 0x20:
dst = append(dst,
[]byte{'\\', 'u', '0', '0', '1', 0x47 + c}...)
}
}
dst = append(dst, '"')
return dst
}