Replaces all ISO-8859-1 or CP1252 characters by their UTF-8 equivalent
resulting in a valid UTF-8 string.
Passing true will forcibly tidy all bytes, assuming that the
string’s encoding is entirely CP1252 or ISO-8859-1.
# File activesupport/lib/active_support/multibyte/unicode.rb, line 227
def tidy_bytes(string, force = false)
if force
return string.unpack("C*").map do |b|
tidy_byte(b)
end.flatten.compact.pack("C*").unpack("U*").pack("U*")
end
bytes = string.unpack("C*")
conts_expected = 0
last_lead = 0
bytes.each_index do |i|
byte = bytes[i]
is_cont = byte > 127 && byte < 192
is_lead = byte > 191 && byte < 245
is_unused = byte > 240
is_restricted = byte > 244
# Impossible or highly unlikely byte? Clean it.
if is_unused || is_restricted
bytes[i] = tidy_byte(byte)
elsif is_cont
# Not expecting contination byte? Clean up. Otherwise, now expect one less.
conts_expected == 0 ? bytes[i] = tidy_byte(byte) : conts_expected -= 1
else
if conts_expected > 0
# Expected continuation, but got ASCII or leading? Clean backwards up to
# the leading byte.
(1..(i - last_lead)).each {|j| bytes[i - j] = tidy_byte(bytes[i - j])}
conts_expected = 0
end
if is_lead
# Final byte is leading? Clean it.
if i == bytes.length - 1
bytes[i] = tidy_byte(bytes.last)
else
# Valid leading byte? Expect continuations determined by position of
# first zero bit, with max of 3.
conts_expected = byte < 224 ? 1 : byte < 240 ? 2 : 3
last_lead = i
end
end
end
end
bytes.empty? ? "" : bytes.flatten.compact.pack("C*").unpack("U*").pack("U*")
end
