# encoding: UTF-8
#
# Copyright 2011, 2012 Keith Rarick
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
# See https://github.com/kr/okjson for updates.
require 'stringio'
# Some parts adapted from
# https://golang.org/src/encoding/json/decode.go and
# https://golang.org/src/unicode/utf8/utf8.go
module Rack::Utils::OkJson
Upstream = '43'
extend self
# 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.
def decode(s)
ts = lex(s)
v, ts = textparse(ts)
if ts.length > 0
raise Error, 'trailing garbage'
end
v
end
# 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.
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
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
raise Error, "cannot encode #{x.class}: #{x.inspect}"
end
end
private
# 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.
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
# Parses a "value" in the sense of RFC 4627.
# Returns the parsed value and any trailing tokens.
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
# Parses an "object" in the sense of RFC 4627.
# Returns the parsed value and any trailing tokens.
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
# Parses a "member" in the sense of RFC 4627.
# Returns the parsed values and any trailing tokens.
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
# Parses an "array" in the sense of RFC 4627.
# Returns the parsed value and any trailing tokens.
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
def eat(typ, ts)
if ts[0][0] != typ
raise Error, "expected #{typ} (got #{ts[0].inspect})"
end
ts[1..-1]
end
# Scans s and returns a list of json tokens,
# excluding white space (as defined in RFC 4627).
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
# 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.
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
def nulltok(s); s[0,4] == 'null' ? [:val, 'null', nil] : [] end
def truetok(s); s[0,4] == 'true' ? [:val, 'true', true] : [] end
def falsetok(s); s[0,5] == 'false' ? [:val, 'false', false] : [] end
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
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
def abbrev(s)
t = s[0,10]
p = t['`']
t = t[0,p] if p
t = t + '...' if t.length < s.length
'`' + t + '`'
end
# 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.
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
# Encodes unicode character u as UTF-8
# bytes in string a at position i.
# Returns the number of bytes written.
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
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
def subst(u1, u2)
if Usurr1 <= u1 && u1 < Usurr2 && Usurr2 <= u2 && u2 < Usurr3
return ((u1-Usurr1)<<10) | (u2-Usurr2) + Usurrself
end
return Ucharerr
end
def surrogate?(u)
Usurr1 <= u && u < Usurr3
end
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
def objenc(x)
'{' + x.map{|k,v| keyenc(k) + ':' + valenc(v)}.join(',') + '}'
end
def arrenc(a)
'[' + a.map{|x| valenc(x)}.join(',') + ']'
end
def keyenc(k)
case k
when String then strenc(k)
else
raise Error, "Hash key is not a string: #{k.inspect}"
end
end
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
def numenc(x)
if ((x.nan? || x.infinite?) rescue false)
raise Error, "Numeric cannot be represented: #{x}"
end
"#{x}"
end
# 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.
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
def rubydoesenc?
::String.method_defined?(:force_encoding)
end
class Utf8Error < ::StandardError
end
class Error < ::StandardError
end
Utagx = 0b1000_0000
Utag2 = 0b1100_0000
Utag3 = 0b1110_0000
Utag4 = 0b1111_0000
Utag5 = 0b1111_1000
Umaskx = 0b0011_1111
Umask2 = 0b0001_1111
Umask3 = 0b0000_1111
Umask4 = 0b0000_0111
Uchar1max = (1<<7) - 1
Uchar2max = (1<<11) - 1
Uchar3max = (1<<16) - 1
Ucharerr = 0xFFFD # unicode "replacement char"
Ustrerr = "\xef\xbf\xbd" # unicode "replacement char"
Usurrself = 0x10000
Usurr1 = 0xd800
Usurr2 = 0xdc00
Usurr3 = 0xe000
Spc = ' '[0]
Unesc = {?b=>?\b, ?f=>?\f, ?n=>?\n, ?r=>?\r, ?t=>?\t}
end
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