582 lines
13 KiB
Ruby
582 lines
13 KiB
Ruby
# Copyright 2011 Keith Rarick
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#
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# Permission is hereby granted, free of charge, to any person obtaining a copy
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# of this software and associated documentation files (the "Software"), to deal
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# in the Software without restriction, including without limitation the rights
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# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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# copies of the Software, and to permit persons to whom the Software is
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# furnished to do so, subject to the following conditions:
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#
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# The above copyright notice and this permission notice shall be included in
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# all copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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# THE SOFTWARE.
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# See https://github.com/kr/okjson for updates.
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require 'stringio'
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# Some parts adapted from
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# http://golang.org/src/pkg/json/decode.go and
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# http://golang.org/src/pkg/utf8/utf8.go
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module OkJson
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extend self
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# Decodes a json document in string s and
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# returns the corresponding ruby value.
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# String s must be valid UTF-8. If you have
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# a string in some other encoding, convert
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# it first.
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#
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# String values in the resulting structure
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# will be UTF-8.
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def decode(s)
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ts = lex(s)
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v, ts = textparse(ts)
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if ts.length > 0
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raise Error, 'trailing garbage'
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end
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v
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end
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# Parses a "json text" in the sense of RFC 4627.
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# Returns the parsed value and any trailing tokens.
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# Note: this is almost the same as valparse,
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# except that it does not accept atomic values.
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def textparse(ts)
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if ts.length < 0
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raise Error, 'empty'
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end
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typ, _, val = ts[0]
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case typ
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when '{' then objparse(ts)
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when '[' then arrparse(ts)
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else
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raise Error, "unexpected #{val.inspect}"
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end
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end
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# Parses a "value" in the sense of RFC 4627.
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# Returns the parsed value and any trailing tokens.
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def valparse(ts)
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if ts.length < 0
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raise Error, 'empty'
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end
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typ, _, val = ts[0]
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case typ
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when '{' then objparse(ts)
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when '[' then arrparse(ts)
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when :val,:str then [val, ts[1..-1]]
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else
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raise Error, "unexpected #{val.inspect}"
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end
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end
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# Parses an "object" in the sense of RFC 4627.
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# Returns the parsed value and any trailing tokens.
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def objparse(ts)
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ts = eat('{', ts)
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obj = {}
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if ts[0][0] == '}'
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return obj, ts[1..-1]
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end
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k, v, ts = pairparse(ts)
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obj[k] = v
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if ts[0][0] == '}'
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return obj, ts[1..-1]
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end
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loop do
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ts = eat(',', ts)
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k, v, ts = pairparse(ts)
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obj[k] = v
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if ts[0][0] == '}'
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return obj, ts[1..-1]
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end
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end
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end
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# Parses a "member" in the sense of RFC 4627.
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# Returns the parsed values and any trailing tokens.
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def pairparse(ts)
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(typ, _, k), ts = ts[0], ts[1..-1]
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if typ != :str
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raise Error, "unexpected #{k.inspect}"
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end
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ts = eat(':', ts)
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v, ts = valparse(ts)
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[k, v, ts]
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end
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# Parses an "array" in the sense of RFC 4627.
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# Returns the parsed value and any trailing tokens.
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def arrparse(ts)
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ts = eat('[', ts)
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arr = []
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if ts[0][0] == ']'
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return arr, ts[1..-1]
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end
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v, ts = valparse(ts)
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arr << v
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if ts[0][0] == ']'
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return arr, ts[1..-1]
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end
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loop do
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ts = eat(',', ts)
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v, ts = valparse(ts)
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arr << v
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if ts[0][0] == ']'
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return arr, ts[1..-1]
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end
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end
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end
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def eat(typ, ts)
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if ts[0][0] != typ
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raise Error, "expected #{typ} (got #{ts[0].inspect})"
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end
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ts[1..-1]
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end
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# Sans s and returns a list of json tokens,
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# excluding white space (as defined in RFC 4627).
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def lex(s)
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ts = []
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while s.length > 0
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typ, lexeme, val = tok(s)
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if typ == nil
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raise Error, "invalid character at #{s[0,10].inspect}"
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end
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if typ != :space
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ts << [typ, lexeme, val]
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end
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s = s[lexeme.length..-1]
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end
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ts
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end
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# Scans the first token in s and
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# returns a 3-element list, or nil
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# if no such token exists.
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#
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# The first list element is one of
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# '{', '}', ':', ',', '[', ']',
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# :val, :str, and :space.
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#
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# The second element is the lexeme.
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#
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# The third element is the value of the
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# token for :val and :str, otherwise
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# it is the lexeme.
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def tok(s)
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case s[0]
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when ?{ then ['{', s[0,1], s[0,1]]
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when ?} then ['}', s[0,1], s[0,1]]
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when ?: then [':', s[0,1], s[0,1]]
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when ?, then [',', s[0,1], s[0,1]]
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when ?[ then ['[', s[0,1], s[0,1]]
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when ?] then [']', s[0,1], s[0,1]]
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when ?n then nulltok(s)
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when ?t then truetok(s)
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when ?f then falsetok(s)
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when ?" then strtok(s)
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when Spc then [:space, s[0,1], s[0,1]]
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when ?\t then [:space, s[0,1], s[0,1]]
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when ?\n then [:space, s[0,1], s[0,1]]
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when ?\r then [:space, s[0,1], s[0,1]]
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else numtok(s)
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end
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end
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def nulltok(s); s[0,4] == 'null' && [:val, 'null', nil] end
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def truetok(s); s[0,4] == 'true' && [:val, 'true', true] end
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def falsetok(s); s[0,5] == 'false' && [:val, 'false', false] end
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def numtok(s)
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m = /-?([1-9][0-9]+|[0-9])([.][0-9]+)?([eE][+-]?[0-9]+)?/.match(s)
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if m && m.begin(0) == 0
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if m[3] && !m[2]
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[:val, m[0], Integer(m[1])*(10**Integer(m[3][1..-1]))]
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elsif m[2]
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[:val, m[0], Float(m[0])]
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else
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[:val, m[0], Integer(m[0])]
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end
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end
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end
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def strtok(s)
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m = /"([^"\\]|\\["\/\\bfnrt]|\\u[0-9a-fA-F]{4})*"/.match(s)
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if ! m
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raise Error, "invalid string literal at #{abbrev(s)}"
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end
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[:str, m[0], unquote(m[0])]
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end
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def abbrev(s)
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t = s[0,10]
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p = t['`']
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t = t[0,p] if p
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t = t + '...' if t.length < s.length
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'`' + t + '`'
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end
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# Converts a quoted json string literal q into a UTF-8-encoded string.
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# The rules are different than for Ruby, so we cannot use eval.
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# Unquote will raise an error if q contains control characters.
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def unquote(q)
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q = q[1...-1]
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a = q.dup # allocate a big enough string
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r, w = 0, 0
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while r < q.length
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c = q[r]
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case true
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when c == ?\\
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r += 1
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if r >= q.length
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raise Error, "string literal ends with a \"\\\": \"#{q}\""
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end
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case q[r]
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when ?",?\\,?/,?'
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a[w] = q[r]
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r += 1
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w += 1
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when ?b,?f,?n,?r,?t
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a[w] = Unesc[q[r]]
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r += 1
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w += 1
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when ?u
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r += 1
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uchar = begin
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hexdec4(q[r,4])
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rescue RuntimeError => e
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raise Error, "invalid escape sequence \\u#{q[r,4]}: #{e}"
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end
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r += 4
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if surrogate? uchar
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if q.length >= r+6
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uchar1 = hexdec4(q[r+2,4])
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uchar = subst(uchar, uchar1)
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if uchar != Ucharerr
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# A valid pair; consume.
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r += 6
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end
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end
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end
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w += ucharenc(a, w, uchar)
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else
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raise Error, "invalid escape char #{q[r]} in \"#{q}\""
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end
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when c == ?", c < Spc
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raise Error, "invalid character in string literal \"#{q}\""
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else
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# Copy anything else byte-for-byte.
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# Valid UTF-8 will remain valid UTF-8.
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# Invalid UTF-8 will remain invalid UTF-8.
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a[w] = c
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r += 1
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w += 1
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end
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end
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a[0,w]
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end
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# Encodes unicode character u as UTF-8
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# bytes in string a at position i.
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# Returns the number of bytes written.
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def ucharenc(a, i, u)
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case true
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when u <= Uchar1max
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a[i] = (u & 0xff).chr
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1
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when u <= Uchar2max
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a[i+0] = (Utag2 | ((u>>6)&0xff)).chr
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a[i+1] = (Utagx | (u&Umaskx)).chr
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2
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when u <= Uchar3max
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a[i+0] = (Utag3 | ((u>>12)&0xff)).chr
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a[i+1] = (Utagx | ((u>>6)&Umaskx)).chr
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a[i+2] = (Utagx | (u&Umaskx)).chr
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3
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else
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a[i+0] = (Utag4 | ((u>>18)&0xff)).chr
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a[i+1] = (Utagx | ((u>>12)&Umaskx)).chr
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a[i+2] = (Utagx | ((u>>6)&Umaskx)).chr
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a[i+3] = (Utagx | (u&Umaskx)).chr
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4
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end
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end
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def hexdec4(s)
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if s.length != 4
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raise Error, 'short'
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end
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(nibble(s[0])<<12) | (nibble(s[1])<<8) | (nibble(s[2])<<4) | nibble(s[3])
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end
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def subst(u1, u2)
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if Usurr1 <= u1 && u1 < Usurr2 && Usurr2 <= u2 && u2 < Usurr3
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return ((u1-Usurr1)<<10) | (u2-Usurr2) + Usurrself
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end
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return Ucharerr
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end
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def unsubst(u)
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if u < Usurrself || u > Umax || surrogate?(u)
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return Ucharerr, Ucharerr
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end
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u -= Usurrself
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[Usurr1 + ((u>>10)&0x3ff), Usurr2 + (u&0x3ff)]
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end
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def surrogate?(u)
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Usurr1 <= u && u < Usurr3
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end
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def nibble(c)
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case true
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when ?0 <= c && c <= ?9 then c.ord - ?0.ord
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when ?a <= c && c <= ?z then c.ord - ?a.ord + 10
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when ?A <= c && c <= ?Z then c.ord - ?A.ord + 10
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else
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raise Error, "invalid hex code #{c}"
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end
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end
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# Encodes x into a json text. It may contain only
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# Array, Hash, String, Numeric, true, false, nil.
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# (Note, this list excludes Symbol.)
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# X itself must be an Array or a Hash.
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# No other value can be encoded, and an error will
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# be raised if x contains any other value, such as
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# Nan, Infinity, Symbol, and Proc, or if a Hash key
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# is not a String.
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# Strings contained in x must be valid UTF-8.
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def encode(x)
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case x
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when Hash then objenc(x)
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when Array then arrenc(x)
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else
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raise Error, 'root value must be an Array or a Hash'
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end
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end
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def valenc(x)
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case x
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when Hash then objenc(x)
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when Array then arrenc(x)
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when String then strenc(x)
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when Numeric then numenc(x)
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when true then "true"
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when false then "false"
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when nil then "null"
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else
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raise Error, "cannot encode #{x.class}: #{x.inspect}"
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end
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end
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def objenc(x)
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'{' + x.map{|k,v| keyenc(k) + ':' + valenc(v)}.join(',') + '}'
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end
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def arrenc(a)
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'[' + a.map{|x| valenc(x)}.join(',') + ']'
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end
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def keyenc(k)
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case k
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when String then strenc(k)
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else
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raise Error, "Hash key is not a string: #{k.inspect}"
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end
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end
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def strenc(s)
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t = StringIO.new
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t.putc(?")
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r = 0
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while r < s.length
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case s[r]
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when ?" then t.print('\\"')
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when ?\\ then t.print('\\\\')
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when ?\b then t.print('\\b')
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when ?\f then t.print('\\f')
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when ?\n then t.print('\\n')
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when ?\r then t.print('\\r')
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when ?\t then t.print('\\t')
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else
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c = s[r]
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case true
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when Spc <= c && c <= ?~
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t.putc(c)
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when true
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u, size = uchardec(s, r)
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r += size - 1 # we add one more at the bottom of the loop
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if u < 0x10000
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t.print('\\u')
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hexenc4(t, u)
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else
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u1, u2 = unsubst(u)
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t.print('\\u')
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hexenc4(t, u1)
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t.print('\\u')
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hexenc4(t, u2)
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end
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else
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# invalid byte; skip it
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end
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end
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r += 1
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end
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t.putc(?")
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t.string
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end
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def hexenc4(t, u)
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t.putc(Hex[(u>>12)&0xf])
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t.putc(Hex[(u>>8)&0xf])
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t.putc(Hex[(u>>4)&0xf])
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t.putc(Hex[u&0xf])
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end
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def numenc(x)
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if x.nan? || x.infinite?
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return 'null'
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end rescue nil
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"#{x}"
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end
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# Decodes unicode character u from UTF-8
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# bytes in string s at position i.
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# Returns u and the number of bytes read.
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def uchardec(s, i)
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n = s.length - i
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return [Ucharerr, 1] if n < 1
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c0 = s[i].ord
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# 1-byte, 7-bit sequence?
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if c0 < Utagx
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return [c0, 1]
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end
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# unexpected continuation byte?
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return [Ucharerr, 1] if c0 < Utag2
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# need continuation byte
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return [Ucharerr, 1] if n < 2
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c1 = s[i+1].ord
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return [Ucharerr, 1] if c1 < Utagx || Utag2 <= c1
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# 2-byte, 11-bit sequence?
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if c0 < Utag3
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u = (c0&Umask2)<<6 | (c1&Umaskx)
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return [Ucharerr, 1] if u <= Uchar1max
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return [u, 2]
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end
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# need second continuation byte
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return [Ucharerr, 1] if n < 3
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c2 = s[i+2].ord
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return [Ucharerr, 1] if c2 < Utagx || Utag2 <= c2
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# 3-byte, 16-bit sequence?
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if c0 < Utag4
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u = (c0&Umask3)<<12 | (c1&Umaskx)<<6 | (c2&Umaskx)
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return [Ucharerr, 1] if u <= Uchar2max
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return [u, 3]
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end
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# need third continuation byte
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return [Ucharerr, 1] if n < 4
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c3 = s[i+3].ord
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return [Ucharerr, 1] if c3 < Utagx || Utag2 <= c3
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# 4-byte, 21-bit sequence?
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if c0 < Utag5
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u = (c0&Umask4)<<18 | (c1&Umaskx)<<12 | (c2&Umaskx)<<6 | (c3&Umaskx)
|
|
return [Ucharerr, 1] if u <= Uchar3max
|
|
return [u, 4]
|
|
end
|
|
|
|
return [Ucharerr, 1]
|
|
end
|
|
|
|
|
|
class Error < ::StandardError
|
|
end
|
|
|
|
|
|
Utagx = 0x80 # 1000 0000
|
|
Utag2 = 0xc0 # 1100 0000
|
|
Utag3 = 0xe0 # 1110 0000
|
|
Utag4 = 0xf0 # 1111 0000
|
|
Utag5 = 0xF8 # 1111 1000
|
|
Umaskx = 0x3f # 0011 1111
|
|
Umask2 = 0x1f # 0001 1111
|
|
Umask3 = 0x0f # 0000 1111
|
|
Umask4 = 0x07 # 0000 0111
|
|
Uchar1max = (1<<7) - 1
|
|
Uchar2max = (1<<11) - 1
|
|
Uchar3max = (1<<16) - 1
|
|
Ucharerr = 0xFFFD # unicode "replacement char"
|
|
Usurrself = 0x10000
|
|
Usurr1 = 0xd800
|
|
Usurr2 = 0xdc00
|
|
Usurr3 = 0xe000
|
|
Umax = 0x10ffff
|
|
|
|
Spc = ' '[0]
|
|
Unesc = {?b=>?\b, ?f=>?\f, ?n=>?\n, ?r=>?\r, ?t=>?\t}
|
|
Hex = '0123456789abcdef'
|
|
end
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