module MultiJson::OkJson

Some parts adapted from golang.org/src/encoding/json/decode.go and golang.org/src/unicode/utf8/utf8.go

Constants

ParseError
Spc
Uchar1max
Uchar2max
Uchar3max
Ucharerr
Umask2
Umask3
Umask4
Umaskx
Unesc
Upstream
Ustrerr
Usurr1
Usurr2
Usurr3
Usurrself
Utag2
Utag3
Utag4
Utag5
Utagx

Public Instance Methods

decode(s) click to toggle source

Decodes a json document in string s and returns the corresponding ruby value. String s must be valid UTF-8. If you have a string in some other encoding, convert it first.

String values in the resulting structure will be UTF-8.

# File lib/multi_json/vendor/okjson.rb, line 44
def decode(s)
  ts = lex(s)
  v, ts = textparse(ts)
  if ts.length > 0
    raise Error, 'trailing garbage'
  end
  v
end
encode(x) click to toggle source

Encodes x into a json text. It may contain only Array, Hash, String, Numeric, true, false, nil. (Note, this list excludes Symbol.) X itself must be an Array or a Hash. No other value can be encoded, and an error will be raised if x contains any other value, such as Nan, Infinity, Symbol, and Proc, or if a Hash key is not a String. Strings contained in x must be valid UTF-8.

# File lib/multi_json/vendor/okjson.rb, line 63
def encode(x)
  case x
  when Hash    then objenc(x)
  when Array   then arrenc(x)
  else
    raise Error, 'root value must be an Array or a Hash'
  end
end
valenc(x) click to toggle source
# File lib/multi_json/vendor/okjson.rb, line 73
def valenc(x)
  case x
  when Hash    then objenc(x)
  when Array   then arrenc(x)
  when String  then strenc(x)
  when Numeric then numenc(x)
  when true    then "true"
  when false   then "false"
  when nil     then "null"
  else
    if x.respond_to?(:to_json)
      x.to_json
    else
      raise Error, "cannot encode #{x.class}: #{x.inspect}"
    end
  end
end

Private Instance Methods

abbrev(s) click to toggle source
# File lib/multi_json/vendor/okjson.rb, line 293
def abbrev(s)
  t = s[0,10]
  p = t['`']
  t = t[0,p] if p
  t = t + '...' if t.length < s.length
  '`' + t + '`'
end
arrenc(a) click to toggle source
# File lib/multi_json/vendor/okjson.rb, line 436
def arrenc(a)
  '[' + a.map{|x| valenc(x)}.join(',') + ']'
end
arrparse(ts) click to toggle source

Parses an “array” in the sense of RFC 4627. Returns the parsed value and any trailing tokens.

# File lib/multi_json/vendor/okjson.rb, line 177
def arrparse(ts)
  ts = eat('[', ts)
  arr = []

  if ts[0][0] == ']'
    return arr, ts[1..-1]
  end

  v, ts = valparse(ts)
  arr << v

  if ts[0][0] == ']'
    return arr, ts[1..-1]
  end

  loop do
    ts = eat(',', ts)

    v, ts = valparse(ts)
    arr << v

    if ts[0][0] == ']'
      return arr, ts[1..-1]
    end
  end
end
eat(typ, ts) click to toggle source
# File lib/multi_json/vendor/okjson.rb, line 205
def eat(typ, ts)
  if ts[0][0] != typ
    raise Error, "expected #{typ} (got #{ts[0].inspect})"
  end
  ts[1..-1]
end
falsetok(s) click to toggle source
# File lib/multi_json/vendor/okjson.rb, line 265
def falsetok(s); s[0,5] == 'false' ? [:val, 'false', false] : [] end
hexdec4(s) click to toggle source
# File lib/multi_json/vendor/okjson.rb, line 400
def hexdec4(s)
  if s.length != 4
    raise Error, 'short'
  end
  (nibble(s[0])<<12) | (nibble(s[1])<<8) | (nibble(s[2])<<4) | nibble(s[3])
end
keyenc(k) click to toggle source
# File lib/multi_json/vendor/okjson.rb, line 441
def keyenc(k)
  case k
  when String then strenc(k)
  else
    raise Error, "Hash key is not a string: #{k.inspect}"
  end
end
lex(s) click to toggle source

Scans s and returns a list of json tokens, excluding white space (as defined in RFC 4627).

# File lib/multi_json/vendor/okjson.rb, line 215
def lex(s)
  ts = []
  while s.length > 0
    typ, lexeme, val = tok(s)
    if typ == nil
      raise Error, "invalid character at #{s[0,10].inspect}"
    end
    if typ != :space
      ts << [typ, lexeme, val]
    end
    s = s[lexeme.length..-1]
  end
  ts
end
nibble(c) click to toggle source
# File lib/multi_json/vendor/okjson.rb, line 421
def nibble(c)
  if ?0 <= c && c <= ?9 then c.ord - ?0.ord
  elsif ?a <= c && c <= ?z then c.ord - ?a.ord + 10
  elsif ?A <= c && c <= ?Z then c.ord - ?A.ord + 10
  else
    raise Error, "invalid hex code #{c}"
  end
end
nulltok(s) click to toggle source
# File lib/multi_json/vendor/okjson.rb, line 263
def nulltok(s);  s[0,4] == 'null'  ? [:val, 'null',  nil]   : [] end
numenc(x) click to toggle source
# File lib/multi_json/vendor/okjson.rb, line 493
def numenc(x)
  if ((x.nan? || x.infinite?) rescue false)
    raise Error, "Numeric cannot be represented: #{x}"
  end
  "#{x}"
end
numtok(s) click to toggle source
# File lib/multi_json/vendor/okjson.rb, line 268
def numtok(s)
  m = /(-?(?:[1-9][0-9]+|[0-9]))([.][0-9]+)?([eE][+-]?[0-9]+)?/.match(s)
  if m && m.begin(0) == 0
    if !m[2] && !m[3]
      [:val, m[0], Integer(m[0])]
    elsif m[2]
      [:val, m[0], Float(m[0])]
    else
      [:val, m[0], Integer(m[1])*(10**m[3][1..-1].to_i(10))]
    end
  else
    []
  end
end
objenc(x) click to toggle source
# File lib/multi_json/vendor/okjson.rb, line 431
def objenc(x)
  '{' + x.map{|k,v| keyenc(k) + ':' + valenc(v)}.join(',') + '}'
end
objparse(ts) click to toggle source

Parses an “object” in the sense of RFC 4627. Returns the parsed value and any trailing tokens.

# File lib/multi_json/vendor/okjson.rb, line 134
def objparse(ts)
  ts = eat('{', ts)
  obj = {}

  if ts[0][0] == '}'
    return obj, ts[1..-1]
  end

  k, v, ts = pairparse(ts)
  obj[k] = v

  if ts[0][0] == '}'
    return obj, ts[1..-1]
  end

  loop do
    ts = eat(',', ts)

    k, v, ts = pairparse(ts)
    obj[k] = v

    if ts[0][0] == '}'
      return obj, ts[1..-1]
    end
  end
end
pairparse(ts) click to toggle source

Parses a “member” in the sense of RFC 4627. Returns the parsed values and any trailing tokens.

# File lib/multi_json/vendor/okjson.rb, line 164
def pairparse(ts)
  (typ, _, k), ts = ts[0], ts[1..-1]
  if typ != :str
    raise Error, "unexpected #{k.inspect}"
  end
  ts = eat(':', ts)
  v, ts = valparse(ts)
  [k, v, ts]
end
rubydoesenc?() click to toggle source
# File lib/multi_json/vendor/okjson.rb, line 571
def rubydoesenc?
  ::String.method_defined?(:force_encoding)
end
strenc(s) click to toggle source
# File lib/multi_json/vendor/okjson.rb, line 450
def strenc(s)
  t = StringIO.new
  t.putc(?")
  r = 0

  while r < s.length
    case s[r]
    when ?"  then t.print('\\"')
    when ?\\ then t.print('\\\\')
    when ?\b then t.print('\\b')
    when ?\f then t.print('\\f')
    when ?\n then t.print('\\n')
    when ?\r then t.print('\\r')
    when ?\t then t.print('\\t')
    else
      c = s[r]
      # In ruby >= 1.9, s[r] is a codepoint, not a byte.
      if rubydoesenc?
        begin
          # c.ord will raise an error if c is invalid UTF-8
          if c.ord < Spc.ord
            c = "\\u%04x" % [c.ord]
          end
          t.write(c)
        rescue
          t.write(Ustrerr)
        end
      elsif c < Spc
        t.write("\\u%04x" % c)
      elsif Spc <= c && c <= ?~
        t.putc(c)
      else
        n = ucharcopy(t, s, r) # ensure valid UTF-8 output
        r += n - 1 # r is incremented below
      end
    end
    r += 1
  end
  t.putc(?")
  t.string
end
strtok(s) click to toggle source
# File lib/multi_json/vendor/okjson.rb, line 284
def strtok(s)
  m = /"([^"\\]|\\["\/\\bfnrt]|\\u[0-9a-fA-F]{4})*"/.match(s)
  if ! m
    raise Error, "invalid string literal at #{abbrev(s)}"
  end
  [:str, m[0], unquote(m[0])]
end
subst(u1, u2) click to toggle source
# File lib/multi_json/vendor/okjson.rb, line 408
def subst(u1, u2)
  if Usurr1 <= u1 && u1 < Usurr2 && Usurr2 <= u2 && u2 < Usurr3
    return ((u1-Usurr1)<<10) | (u2-Usurr2) + Usurrself
  end
  return Ucharerr
end
surrogate?(u) click to toggle source
# File lib/multi_json/vendor/okjson.rb, line 416
def surrogate?(u)
  Usurr1 <= u && u < Usurr3
end
textparse(ts) click to toggle source

Parses a “json text” in the sense of RFC 4627. Returns the parsed value and any trailing tokens. Note: this is almost the same as valparse, except that it does not accept atomic values.

# File lib/multi_json/vendor/okjson.rb, line 99
def textparse(ts)
  if ts.length <= 0
    raise Error, 'empty'
  end

  typ, _, val = ts[0]
  case typ
  when '{' then objparse(ts)
  when '[' then arrparse(ts)
  else
    raise Error, "unexpected #{val.inspect}"
  end
end
tok(s) click to toggle source

Scans the first token in s and returns a 3-element list, or nil if s does not begin with a valid token.

The first list element is one of ‘{’, ‘}’, ‘:’, ‘,’, ‘[’, ‘]’, :val, :str, and :space.

The second element is the lexeme.

The third element is the value of the token for :val and :str, otherwise it is the lexeme.

# File lib/multi_json/vendor/okjson.rb, line 244
def tok(s)
  case s[0]
  when ?{ then ['{', s[0,1], s[0,1]]
  when ?} then ['}', s[0,1], s[0,1]]
  when ?: then [':', s[0,1], s[0,1]]
  when ?, then [',', s[0,1], s[0,1]]
  when ?[ then ['[', s[0,1], s[0,1]]
  when ?] then [']', s[0,1], s[0,1]]
  when ?n then nulltok(s)
  when ?t then truetok(s)
  when ?f then falsetok(s)
  when ?" then strtok(s)
  when Spc, ?\t, ?\n, ?\r then [:space, s[0,1], s[0,1]]
  else
    numtok(s)
  end
end
truetok(s) click to toggle source
# File lib/multi_json/vendor/okjson.rb, line 264
def truetok(s);  s[0,4] == 'true'  ? [:val, 'true',  true]  : [] end
ucharcopy(t, s, i) click to toggle source

Copies the valid UTF-8 bytes of a single character from string s at position i to I/O object t, and returns the number of bytes copied. If no valid UTF-8 char exists at position i, ucharcopy writes Ustrerr and returns 1.

# File lib/multi_json/vendor/okjson.rb, line 506
def ucharcopy(t, s, i)
  n = s.length - i
  raise Utf8Error if n < 1

  c0 = s[i].ord

  # 1-byte, 7-bit sequence?
  if c0 < Utagx
    t.putc(c0)
    return 1
  end

  raise Utf8Error if c0 < Utag2 # unexpected continuation byte?

  raise Utf8Error if n < 2 # need continuation byte
  c1 = s[i+1].ord
  raise Utf8Error if c1 < Utagx || Utag2 <= c1

  # 2-byte, 11-bit sequence?
  if c0 < Utag3
    raise Utf8Error if ((c0&Umask2)<<6 | (c1&Umaskx)) <= Uchar1max
    t.putc(c0)
    t.putc(c1)
    return 2
  end

  # need second continuation byte
  raise Utf8Error if n < 3

  c2 = s[i+2].ord
  raise Utf8Error if c2 < Utagx || Utag2 <= c2

  # 3-byte, 16-bit sequence?
  if c0 < Utag4
    u = (c0&Umask3)<<12 | (c1&Umaskx)<<6 | (c2&Umaskx)
    raise Utf8Error if u <= Uchar2max
    t.putc(c0)
    t.putc(c1)
    t.putc(c2)
    return 3
  end

  # need third continuation byte
  raise Utf8Error if n < 4
  c3 = s[i+3].ord
  raise Utf8Error if c3 < Utagx || Utag2 <= c3

  # 4-byte, 21-bit sequence?
  if c0 < Utag5
    u = (c0&Umask4)<<18 | (c1&Umaskx)<<12 | (c2&Umaskx)<<6 | (c3&Umaskx)
    raise Utf8Error if u <= Uchar3max
    t.putc(c0)
    t.putc(c1)
    t.putc(c2)
    t.putc(c3)
    return 4
  end

  raise Utf8Error
rescue Utf8Error
  t.write(Ustrerr)
  return 1
end
ucharenc(a, i, u) click to toggle source

Encodes unicode character u as UTF-8 bytes in string a at position i. Returns the number of bytes written.

# File lib/multi_json/vendor/okjson.rb, line 377
def ucharenc(a, i, u)
  if u <= Uchar1max
    a[i] = (u & 0xff).chr
    1
  elsif u <= Uchar2max
    a[i+0] = (Utag2 | ((u>>6)&0xff)).chr
    a[i+1] = (Utagx | (u&Umaskx)).chr
    2
  elsif u <= Uchar3max
    a[i+0] = (Utag3 | ((u>>12)&0xff)).chr
    a[i+1] = (Utagx | ((u>>6)&Umaskx)).chr
    a[i+2] = (Utagx | (u&Umaskx)).chr
    3
  else
    a[i+0] = (Utag4 | ((u>>18)&0xff)).chr
    a[i+1] = (Utagx | ((u>>12)&Umaskx)).chr
    a[i+2] = (Utagx | ((u>>6)&Umaskx)).chr
    a[i+3] = (Utagx | (u&Umaskx)).chr
    4
  end
end
unquote(q) click to toggle source

Converts a quoted json string literal q into a UTF-8-encoded string. The rules are different than for Ruby, so we cannot use eval. Unquote will raise an error if q contains control characters.

# File lib/multi_json/vendor/okjson.rb, line 305
def unquote(q)
  q = q[1...-1]
  a = q.dup # allocate a big enough string
  # In ruby >= 1.9, a[w] is a codepoint, not a byte.
  if rubydoesenc?
    a.force_encoding('UTF-8')
  end
  r, w = 0, 0
  while r < q.length
    c = q[r]
    if c == ?\\
      r += 1
      if r >= q.length
        raise Error, "string literal ends with a \"\\\": \"#{q}\""
      end

      case q[r]
      when ?",?\\,?/,?'
        a[w] = q[r]
        r += 1
        w += 1
      when ?b,?f,?n,?r,?t
        a[w] = Unesc[q[r]]
        r += 1
        w += 1
      when ?u
        r += 1
        uchar = begin
          hexdec4(q[r,4])
        rescue RuntimeError => e
          raise Error, "invalid escape sequence \\u#{q[r,4]}: #{e}"
        end
        r += 4
        if surrogate? uchar
          if q.length >= r+6
            uchar1 = hexdec4(q[r+2,4])
            uchar = subst(uchar, uchar1)
            if uchar != Ucharerr
              # A valid pair; consume.
              r += 6
            end
          end
        end
        if rubydoesenc?
          a[w] = '' << uchar
          w += 1
        else
          w += ucharenc(a, w, uchar)
        end
      else
        raise Error, "invalid escape char #{q[r]} in \"#{q}\""
      end
    elsif c == ?" || c < Spc
      raise Error, "invalid character in string literal \"#{q}\""
    else
      # Copy anything else byte-for-byte.
      # Valid UTF-8 will remain valid UTF-8.
      # Invalid UTF-8 will remain invalid UTF-8.
      # In ruby >= 1.9, c is a codepoint, not a byte,
      # in which case this is still what we want.
      a[w] = c
      r += 1
      w += 1
    end
  end
  a[0,w]
end
valparse(ts) click to toggle source

Parses a “value” in the sense of RFC 4627. Returns the parsed value and any trailing tokens.

# File lib/multi_json/vendor/okjson.rb, line 116
def valparse(ts)
  if ts.length <= 0
    raise Error, 'empty'
  end

  typ, _, val = ts[0]
  case typ
  when '{' then objparse(ts)
  when '[' then arrparse(ts)
  when :val,:str then [val, ts[1..-1]]
  else
    raise Error, "unexpected #{val.inspect}"
  end
end