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#JSON Parser
#Adapted from http://www.mathworks.com/matlabcentral/fileexchange/23393
#Original BSD Licence, (c) 2011, François Glineur
function parse_json(strng::String)
pos = 1
len = length(strng)
# String delimiters and escape characters are identified beforehand to improve speed
# esc = regexp(str, "[\"\\\\]"); index_esc = 1; len_esc = length(esc); #TODO Enable for speed
function parse_object()
parse_char('{')
object = Dict{String, Any}()
if next_char() != '}'
while true
str = parse_string()
if isempty(str)
error("Name of value at position $pos cannot be empty")
end
parse_char(':')
val = parse_value()
object[str] = val
if next_char() == '}'
break
end
parse_char(',')
end
end
parse_char('}')
return object
end
function parse_array()
parse_char('[')
object = Set()
if next_char != ']'
while true
val = parse_value()
push!(object, val)
if next_char() == ']'
break
end
parse_char(',')
end
end
parse_char(']')
return object
end
function parse_char(c::Char)
skip_whitespace()
if pos > len || strng[pos] != c
error("Expected $c at position $pos")
else
pos = pos + 1
skip_whitespace()
end
end
function next_char()
skip_whitespace()
if pos > len
c = '\0'
else
c = strng[pos]
end
end
function skip_whitespace()
while pos <= len && isspace(strng[pos])
pos = pos + 1
end
end
function parse_string()
if strng[pos] != '"'
error("String starting with quotation expected at position $pos")
else
pos = pos + 1
end
str = ""
while pos <= len
# while index_esc <= len_esc && esc(index_esc) < pos
# index_esc = index_esc + 1
# end
# if index_esc > len_esc
# str = string(str, strng[pos:end])
# pos = len + 1
# break
# else
# str = string(str, strng[pos:esc(index_esc)-1])
# pos = esc(index_esc)
# end
nc = strng[pos]
if nc == '"'
pos = pos + 1
return string(str)
elseif nc == '\\'
if pos+1 > len
error_pos("End of file reached right after escape character")
end
pos = pos + 1
anc = strng[pos]
if anc == '"' || anc == '\\' || anc == '/'
str = string(str, strng[pos])
pos = pos + 1
elseif anc == 'b' || anc == 'f'|| anc == 'n' || anc == 'r' || anc == 't'
str = string(str, '\\', string[pos])
pos = pos + 1
elseif anc == 'u'
if pos+4 > len
error_pos("End of file reached in escaped unicode character")
end
str = string(str, strng[pos-1:pos+4])
pos = pos + 5
end
else # should never happen
str = string(str,strng[pos])
pos = pos + 1
end
end
error("End of file while expecting end of string")
end
function parse_number()
num_regex = r"^[\w]?[-+]?[0-9]*\.?[0-9]+([eE][-+]?[0-9]+)?[\w]?"
m = match(num_regex, strng[pos:min(len,pos+20)])
if m === nothing
error("Error reading number at position $pos")
end
delta = m.offset + length(m.match)
pos = pos + delta -1
return float(m.match)
end
function parse_value()
nc = strng[pos]
if nc == '"'
val = parse_string()
return val
elseif nc == '['
val = parse_array()
return val
elseif nc == '{'
val = parse_object()
return val
elseif nc == '-' || nc == '0' || nc == '1' || nc == '2' || nc == '3' || nc == '4' || nc == '5' || nc == '6' || nc == '7' || nc == '8' || nc == '9'
val = parse_number()
return val
elseif nc == 't'
if pos+3 <= len && strng[pos:pos+3] == "true"
val = true
pos = pos + 4
return val
end
elseif nc == 'f'
if pos+4 <= len && strng[pos:pos+4] == "false"
val = false
pos = pos + 5
return val
end
elseif nc == 'n'
if pos+3 <= len && strng[pos:pos+3] == "null"
val = []
pos = pos + 4
return val
end
end
error("Value expected at position $pos")
end
if pos <= len
nc = next_char()
if nc == '{'
return parse_object()
elseif nc == '['
return parse_array()
else
error("Outer level structure must be an object or an array")
end
end
end
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