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-rw-r--r--ext/json/lib/json/pure/parser.rb259
1 files changed, 259 insertions, 0 deletions
diff --git a/ext/json/lib/json/pure/parser.rb b/ext/json/lib/json/pure/parser.rb
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+++ b/ext/json/lib/json/pure/parser.rb
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+require 'strscan'
+
+module JSON
+ module Pure
+ # This class implements the JSON parser that is used to parse a JSON string
+ # into a Ruby data structure.
+ class Parser < StringScanner
+ STRING = /" ((?:[^\x0-\x1f"\\] |
+ \\["\\\/bfnrt] |
+ \\u[0-9a-fA-F]{4} |
+ \\[\x20-\xff])*)
+ "/nx
+ INTEGER = /(-?0|-?[1-9]\d*)/
+ FLOAT = /(-?
+ (?:0|[1-9]\d*)
+ (?:
+ \.\d+(?i:e[+-]?\d+) |
+ \.\d+ |
+ (?i:e[+-]?\d+)
+ )
+ )/x
+ NAN = /NaN/
+ INFINITY = /Infinity/
+ MINUS_INFINITY = /-Infinity/
+ OBJECT_OPEN = /\{/
+ OBJECT_CLOSE = /\}/
+ ARRAY_OPEN = /\[/
+ ARRAY_CLOSE = /\]/
+ PAIR_DELIMITER = /:/
+ COLLECTION_DELIMITER = /,/
+ TRUE = /true/
+ FALSE = /false/
+ NULL = /null/
+ IGNORE = %r(
+ (?:
+ //[^\n\r]*[\n\r]| # line comments
+ /\* # c-style comments
+ (?:
+ [^*/]| # normal chars
+ /[^*]| # slashes that do not start a nested comment
+ \*[^/]| # asterisks that do not end this comment
+ /(?=\*/) # single slash before this comment's end
+ )*
+ \*/ # the End of this comment
+ |[ \t\r\n]+ # whitespaces: space, horicontal tab, lf, cr
+ )+
+ )mx
+
+ UNPARSED = Object.new
+
+ # Creates a new JSON::Pure::Parser instance for the string _source_.
+ #
+ # It will be configured by the _opts_ hash. _opts_ can have the following
+ # keys:
+ # * *max_nesting*: The maximum depth of nesting allowed in the parsed data
+ # structures. Disable depth checking with :max_nesting => false|nil|0,
+ # it defaults to 19.
+ # * *allow_nan*: If set to true, allow NaN, Infinity and -Infinity in
+ # defiance of RFC 4627 to be parsed by the Parser. This option defaults
+ # to false.
+ # * *create_additions*: If set to false, the Parser doesn't create
+ # additions even if a matchin class and create_id was found. This option
+ # defaults to true.
+ def initialize(source, opts = {})
+ super
+ if !opts.key?(:max_nesting) # defaults to 19
+ @max_nesting = 19
+ elsif opts[:max_nesting]
+ @max_nesting = opts[:max_nesting]
+ else
+ @max_nesting = 0
+ end
+ @allow_nan = !!opts[:allow_nan]
+ ca = true
+ ca = opts[:create_additions] if opts.key?(:create_additions)
+ @create_id = ca ? JSON.create_id : nil
+ end
+
+ alias source string
+
+ # Parses the current JSON string _source_ and returns the complete data
+ # structure as a result.
+ def parse
+ reset
+ obj = nil
+ until eos?
+ case
+ when scan(OBJECT_OPEN)
+ obj and raise ParserError, "source '#{peek(20)}' not in JSON!"
+ @current_nesting = 1
+ obj = parse_object
+ when scan(ARRAY_OPEN)
+ obj and raise ParserError, "source '#{peek(20)}' not in JSON!"
+ @current_nesting = 1
+ obj = parse_array
+ when skip(IGNORE)
+ ;
+ else
+ raise ParserError, "source '#{peek(20)}' not in JSON!"
+ end
+ end
+ obj or raise ParserError, "source did not contain any JSON!"
+ obj
+ end
+
+ private
+
+ # Unescape characters in strings.
+ UNESCAPE_MAP = Hash.new { |h, k| h[k] = k.chr }
+ UNESCAPE_MAP.update({
+ ?" => '"',
+ ?\\ => '\\',
+ ?/ => '/',
+ ?b => "\b",
+ ?f => "\f",
+ ?n => "\n",
+ ?r => "\r",
+ ?t => "\t",
+ ?u => nil,
+ })
+
+ def parse_string
+ if scan(STRING)
+ return '' if self[1].empty?
+ self[1].gsub(%r((?:\\[\\bfnrt"/]|(?:\\u(?:[A-Fa-f\d]{4}))+|\\[\x20-\xff]))n) do |c|
+ if u = UNESCAPE_MAP[c[1]]
+ u
+ else # \uXXXX
+ bytes = ''
+ i = 0
+ while c[6 * i] == ?\\ && c[6 * i + 1] == ?u
+ bytes << c[6 * i + 2, 2].to_i(16) << c[6 * i + 4, 2].to_i(16)
+ i += 1
+ end
+ JSON::UTF16toUTF8.iconv(bytes)
+ end
+ end
+ else
+ UNPARSED
+ end
+ rescue Iconv::Failure => e
+ raise GeneratorError, "Caught #{e.class}: #{e}"
+ end
+
+ def parse_value
+ case
+ when scan(FLOAT)
+ Float(self[1])
+ when scan(INTEGER)
+ Integer(self[1])
+ when scan(TRUE)
+ true
+ when scan(FALSE)
+ false
+ when scan(NULL)
+ nil
+ when (string = parse_string) != UNPARSED
+ string
+ when scan(ARRAY_OPEN)
+ @current_nesting += 1
+ ary = parse_array
+ @current_nesting -= 1
+ ary
+ when scan(OBJECT_OPEN)
+ @current_nesting += 1
+ obj = parse_object
+ @current_nesting -= 1
+ obj
+ when @allow_nan && scan(NAN)
+ NaN
+ when @allow_nan && scan(INFINITY)
+ Infinity
+ when @allow_nan && scan(MINUS_INFINITY)
+ MinusInfinity
+ else
+ UNPARSED
+ end
+ end
+
+ def parse_array
+ raise NestingError, "nesting of #@current_nesting is to deep" if
+ @max_nesting.nonzero? && @current_nesting > @max_nesting
+ result = []
+ delim = false
+ until eos?
+ case
+ when (value = parse_value) != UNPARSED
+ delim = false
+ result << value
+ skip(IGNORE)
+ if scan(COLLECTION_DELIMITER)
+ delim = true
+ elsif match?(ARRAY_CLOSE)
+ ;
+ else
+ raise ParserError, "expected ',' or ']' in array at '#{peek(20)}'!"
+ end
+ when scan(ARRAY_CLOSE)
+ if delim
+ raise ParserError, "expected next element in array at '#{peek(20)}'!"
+ end
+ break
+ when skip(IGNORE)
+ ;
+ else
+ raise ParserError, "unexpected token in array at '#{peek(20)}'!"
+ end
+ end
+ result
+ end
+
+ def parse_object
+ raise NestingError, "nesting of #@current_nesting is to deep" if
+ @max_nesting.nonzero? && @current_nesting > @max_nesting
+ result = {}
+ delim = false
+ until eos?
+ case
+ when (string = parse_string) != UNPARSED
+ skip(IGNORE)
+ unless scan(PAIR_DELIMITER)
+ raise ParserError, "expected ':' in object at '#{peek(20)}'!"
+ end
+ skip(IGNORE)
+ unless (value = parse_value).equal? UNPARSED
+ result[string] = value
+ delim = false
+ skip(IGNORE)
+ if scan(COLLECTION_DELIMITER)
+ delim = true
+ elsif match?(OBJECT_CLOSE)
+ ;
+ else
+ raise ParserError, "expected ',' or '}' in object at '#{peek(20)}'!"
+ end
+ else
+ raise ParserError, "expected value in object at '#{peek(20)}'!"
+ end
+ when scan(OBJECT_CLOSE)
+ if delim
+ raise ParserError, "expected next name, value pair in object at '#{peek(20)}'!"
+ end
+ if @create_id and klassname = result[@create_id]
+ klass = JSON.deep_const_get klassname
+ break unless klass and klass.json_creatable?
+ result = klass.json_create(result)
+ end
+ break
+ when skip(IGNORE)
+ ;
+ else
+ raise ParserError, "unexpected token in object at '#{peek(20)}'!"
+ end
+ end
+ result
+ end
+ end
+ end
+end