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Replace StringScanner #453

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Merged
gkellogg merged 1 commit into from
May 18, 2025
+7 −17
Merged

Replace StringScanner #453

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24 changes: 7 additions & 17 deletions lib/rdf/ntriples/reader.rb
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Original file line number Diff line number Diff line change
Expand Up @@ -40,8 +40,8 @@ class Reader < RDF::Reader

# @see http://www.w3.org/TR/rdf-testcases/#ntrip_strings
ESCAPE_CHARS = ["\b", "\f", "\t", "\n", "\r", "\"", "'", "\\"].freeze
UCHAR4 = /\\u([0-9A-Fa-f]{4,4})/.freeze
UCHAR8 = /\\U([0-9A-Fa-f]{8,8})/.freeze
UCHAR4 = /(?<!\\)\\(?!\\)u([0-9A-Fa-f]{4,4})/.freeze
UCHAR8 = /(?<!\\)\\(?!\\)U([0-9A-Fa-f]{8,8})/.freeze
UCHAR = Regexp.union(UCHAR4, UCHAR8).freeze


Expand Down Expand Up @@ -187,22 +187,12 @@ def self.unescape(string)
# Note: avoiding copying the input string when no escaping is needed
# greatly reduces the number of allocations and the processing time.
string = string.dup.force_encoding(Encoding::UTF_8) unless string.encoding == Encoding::UTF_8
scanner = StringScanner.new(string)

buffer = ""

while !scanner.eos?
buffer << if scanner.scan(ESCAPE_CHARS_ESCAPED_REGEXP)
ESCAPE_CHARS_ESCAPED[scanner.matched]
elsif scanner.scan(UCHAR)
scanner.matched.sub(UCHAR) {[($1 || $2).hex].pack('U*')}
else
# Scan one character
scanner.getch
end
end

buffer
string
.gsub(UCHAR) do
[($1 || $2).hex].pack('U*')
end
.gsub(ESCAPE_CHARS_ESCAPED_REGEXP, ESCAPE_CHARS_ESCAPED)
end

##
Expand Down