diff --git a/json.lua b/json.lua index 08a7cc2..0294d17 100644 --- a/json.lua +++ b/json.lua @@ -22,7 +22,10 @@ -- SOFTWARE. -- -local json = { _version = "0.1.2" } +local json = { + _version = "0.1.2" , + SPARSELIMIT = 100, -- To set the limit on how long sparse arrays can be +} ------------------------------------------------------------------------------- -- Encode @@ -31,28 +34,28 @@ local json = { _version = "0.1.2" } local encode local escape_char_map = { - [ "\\" ] = "\\", - [ "\"" ] = "\"", - [ "\b" ] = "b", - [ "\f" ] = "f", - [ "\n" ] = "n", - [ "\r" ] = "r", - [ "\t" ] = "t", + [ "\\" ] = "\\", + [ "\"" ] = "\"", + [ "\b" ] = "b", + [ "\f" ] = "f", + [ "\n" ] = "n", + [ "\r" ] = "r", + [ "\t" ] = "t", } local escape_char_map_inv = { [ "/" ] = "/" } for k, v in pairs(escape_char_map) do - escape_char_map_inv[v] = k + escape_char_map_inv[v] = k end local function escape_char(c) - return "\\" .. (escape_char_map[c] or string.format("u%04x", c:byte())) + return "\\" .. (escape_char_map[c] or string.format("u%04x", c:byte())) end local function encode_nil(val) - return "null" + return "null" end @@ -70,7 +73,7 @@ local function encode_table(val, stack) local nLen = 0 local count = 0 for k,v in pairs(val) do - if (type(k) ~= "number" or k<=0) and not (k == "n" and type(v) == "number") then + if (type(k) ~= "number" or k<=0 or k%1 ~= 0) and not (k == "n" and type(v) == "number") then array = nil break -- Treat as object else @@ -87,7 +90,7 @@ local function encode_table(val, stack) if nLen > length then length = nLen end - if array and not (length > 100 and count ~= length) then -- Check Array detected but sparse > 100 length then treat as object + if array and not (length > SPARSELIMIT and count ~= length) then -- Check Array detected but sparse > 100 length then treat as object -- Encode for i=1,length do table.insert(res, encode(val[i], stack)) @@ -97,11 +100,6 @@ local function encode_table(val, stack) else -- Treat as an object for k, v in pairs(val) do - --[[ - if type(k) ~= "string" then - error("invalid table: mixed or invalid key types") - end - ]] table.insert(res, encode(k, stack) .. ":" .. encode(v, stack)) end stack[val] = nil @@ -116,35 +114,35 @@ end local function encode_number(val) - -- Check for NaN, -inf and inf - if val ~= val or val <= -math.huge or val >= math.huge then - error("unexpected number value '" .. tostring(val) .. "'") - end - return tostring(val) + -- Check for NaN, -inf and inf + if val ~= val or val <= -math.huge or val >= math.huge then + error("unexpected number value '" .. tostring(val) .. "'") + end + return string.format("%.14g",val) end local type_func_map = { - [ "nil" ] = encode_nil, - [ "table" ] = encode_table, - [ "string" ] = encode_string, - [ "number" ] = encode_number, - [ "boolean" ] = tostring, + [ "nil" ] = encode_nil, + [ "table" ] = encode_table, + [ "string" ] = encode_string, + [ "number" ] = encode_number, + [ "boolean" ] = tostring, } encode = function(val, stack) - local t = type(val) - local f = type_func_map[t] - if f then - return f(val, stack) - end - error("unexpected type '" .. t .. "'") + local t = type(val) + local f = type_func_map[t] + if f then + return f(val, stack) + end + error("unexpected type '" .. t .. "'") end function json.encode(val) - return ( encode(val) ) + return ( encode(val) ) end @@ -155,11 +153,11 @@ end local parse local function create_set(...) - local res = {} - for i = 1, select("#", ...) do - res[ select(i, ...) ] = true - end - return res + local res = {} + for i = 1, select("#", ...) do + res[ select(i, ...) ] = true + end + return res end local space_chars = create_set(" ", "\t", "\r", "\n") @@ -168,232 +166,232 @@ local escape_chars = create_set("\\", "/", '"', "b", "f", "n", "r", "t", "u") local literals = create_set("true", "false", "null") local literal_map = { - [ "true" ] = true, - [ "false" ] = false, - [ "null" ] = nil, + [ "true" ] = true, + [ "false" ] = false, + [ "null" ] = nil, } local function next_char(str, idx, set, negate) - for i = idx, #str do - if set[str:sub(i, i)] ~= negate then - return i - end - end - return #str + 1 + for i = idx, #str do + if set[str:sub(i, i)] ~= negate then + return i + end + end + return #str + 1 end local function decode_error(str, idx, msg) - local line_count = 1 - local col_count = 1 - for i = 1, idx - 1 do - col_count = col_count + 1 - if str:sub(i, i) == "\n" then - line_count = line_count + 1 - col_count = 1 - end - end - error( string.format("%s at line %d col %d", msg, line_count, col_count) ) + local line_count = 1 + local col_count = 1 + for i = 1, idx - 1 do + col_count = col_count + 1 + if str:sub(i, i) == "\n" then + line_count = line_count + 1 + col_count = 1 + end + end + error( string.format("%s at line %d col %d", msg, line_count, col_count) ) end local function codepoint_to_utf8(n) - -- http://scripts.sil.org/cms/scripts/page.php?site_id=nrsi&id=iws-appendixa - local f = math.floor - if n <= 0x7f then - return string.char(n) - elseif n <= 0x7ff then - return string.char(f(n / 64) + 192, n % 64 + 128) - elseif n <= 0xffff then - return string.char(f(n / 4096) + 224, f(n % 4096 / 64) + 128, n % 64 + 128) - elseif n <= 0x10ffff then - return string.char(f(n / 262144) + 240, f(n % 262144 / 4096) + 128, - f(n % 4096 / 64) + 128, n % 64 + 128) - end - error( string.format("invalid unicode codepoint '%x'", n) ) + -- http://scripts.sil.org/cms/scripts/page.php?site_id=nrsi&id=iws-appendixa + local f = math.floor + if n <= 0x7f then + return string.char(n) + elseif n <= 0x7ff then + return string.char(f(n / 64) + 192, n % 64 + 128) + elseif n <= 0xffff then + return string.char(f(n / 4096) + 224, f(n % 4096 / 64) + 128, n % 64 + 128) + elseif n <= 0x10ffff then + return string.char(f(n / 262144) + 240, f(n % 262144 / 4096) + 128, + f(n % 4096 / 64) + 128, n % 64 + 128) + end + error( string.format("invalid unicode codepoint '%x'", n) ) end local function parse_unicode_escape(s) - local n1 = tonumber( s:sub(1, 4), 16 ) - local n2 = tonumber( s:sub(7, 10), 16 ) - -- Surrogate pair? - if n2 then - return codepoint_to_utf8((n1 - 0xd800) * 0x400 + (n2 - 0xdc00) + 0x10000) - else - return codepoint_to_utf8(n1) - end + local n1 = tonumber( s:sub(1, 4), 16 ) + local n2 = tonumber( s:sub(7, 10), 16 ) + -- Surrogate pair? + if n2 then + return codepoint_to_utf8((n1 - 0xd800) * 0x400 + (n2 - 0xdc00) + 0x10000) + else + return codepoint_to_utf8(n1) + end end local function parse_string(str, i) - local res = "" - local j = i + 1 - local k = j + local res = "" + local j = i + 1 + local k = j - while j <= #str do - local x = str:byte(j) + while j <= #str do + local x = str:byte(j) - if x < 32 then - decode_error(str, j, "control character in string") + if x < 32 then + decode_error(str, j, "control character in string") - elseif x == 92 then -- `\`: Escape - res = res .. str:sub(k, j - 1) - j = j + 1 - local c = str:sub(j, j) - if c == "u" then - local hex = str:match("^[dD][89aAbB]%x%x\\u%x%x%x%x", j + 1) - or str:match("^%x%x%x%x", j + 1) - or decode_error(str, j - 1, "invalid unicode escape in string") - res = res .. parse_unicode_escape(hex) - j = j + #hex - else - if not escape_chars[c] then - decode_error(str, j - 1, "invalid escape char '" .. c .. "' in string") - end - res = res .. escape_char_map_inv[c] - end - k = j + 1 + elseif x == 92 then -- `\`: Escape + res = res .. str:sub(k, j - 1) + j = j + 1 + local c = str:sub(j, j) + if c == "u" then + local hex = str:match("^[dD][89aAbB]%x%x\\u%x%x%x%x", j + 1) + or str:match("^%x%x%x%x", j + 1) + or decode_error(str, j - 1, "invalid unicode escape in string") + res = res .. parse_unicode_escape(hex) + j = j + #hex + else + if not escape_chars[c] then + decode_error(str, j - 1, "invalid escape char '" .. c .. "' in string") + end + res = res .. escape_char_map_inv[c] + end + k = j + 1 - elseif x == 34 then -- `"`: End of string - res = res .. str:sub(k, j - 1) - return res, j + 1 - end + elseif x == 34 then -- `"`: End of string + res = res .. str:sub(k, j - 1) + return res, j + 1 + end - j = j + 1 - end + j = j + 1 + end - decode_error(str, i, "expected closing quote for string") + decode_error(str, i, "expected closing quote for string") end local function parse_number(str, i) - local x = next_char(str, i, delim_chars) - local s = str:sub(i, x - 1) - local n = tonumber(s) - if not n then - decode_error(str, i, "invalid number '" .. s .. "'") - end - return n, x + local x = next_char(str, i, delim_chars) + local s = str:sub(i, x - 1) + local n = tonumber(s) + if not n then + decode_error(str, i, "invalid number '" .. s .. "'") + end + return n, x end local function parse_literal(str, i) - local x = next_char(str, i, delim_chars) - local word = str:sub(i, x - 1) - if not literals[word] then - decode_error(str, i, "invalid literal '" .. word .. "'") - end - return literal_map[word], x + local x = next_char(str, i, delim_chars) + local word = str:sub(i, x - 1) + if not literals[word] then + decode_error(str, i, "invalid literal '" .. word .. "'") + end + return literal_map[word], x end local function parse_array(str, i) - local res = {} - local n = 1 - i = i + 1 - while 1 do - local x - i = next_char(str, i, space_chars, true) - -- Empty / end of array? - if str:sub(i, i) == "]" then - i = i + 1 - break - end - -- Read token - x, i = parse(str, i) - res[n] = x - n = n + 1 - -- Next token - i = next_char(str, i, space_chars, true) - local chr = str:sub(i, i) - i = i + 1 - if chr == "]" then break end - if chr ~= "," then decode_error(str, i, "expected ']' or ','") end - end - return res, i + local res = {} + local n = 1 + i = i + 1 + while 1 do + local x + i = next_char(str, i, space_chars, true) + -- Empty / end of array? + if str:sub(i, i) == "]" then + i = i + 1 + break + end + -- Read token + x, i = parse(str, i) + res[n] = x + n = n + 1 + -- Next token + i = next_char(str, i, space_chars, true) + local chr = str:sub(i, i) + i = i + 1 + if chr == "]" then break end + if chr ~= "," then decode_error(str, i, "expected ']' or ','") end + end + return res, i end local function parse_object(str, i) - local res = {} - i = i + 1 - while 1 do - local key, val - i = next_char(str, i, space_chars, true) - -- Empty / end of object? - if str:sub(i, i) == "}" then - i = i + 1 - break - end - -- Read key - if str:sub(i, i) ~= '"' then - decode_error(str, i, "expected string for key") - end - key, i = parse(str, i) - -- Read ':' delimiter - i = next_char(str, i, space_chars, true) - if str:sub(i, i) ~= ":" then - decode_error(str, i, "expected ':' after key") - end - i = next_char(str, i + 1, space_chars, true) - -- Read value - val, i = parse(str, i) - -- Set - res[key] = val - -- Next token - i = next_char(str, i, space_chars, true) - local chr = str:sub(i, i) - i = i + 1 - if chr == "}" then break end - if chr ~= "," then decode_error(str, i, "expected '}' or ','") end - end - return res, i + local res = {} + i = i + 1 + while 1 do + local key, val + i = next_char(str, i, space_chars, true) + -- Empty / end of object? + if str:sub(i, i) == "}" then + i = i + 1 + break + end + -- Read key + if str:sub(i, i) ~= '"' then + decode_error(str, i, "expected string for key") + end + key, i = parse(str, i) + -- Read ':' delimiter + i = next_char(str, i, space_chars, true) + if str:sub(i, i) ~= ":" then + decode_error(str, i, "expected ':' after key") + end + i = next_char(str, i + 1, space_chars, true) + -- Read value + val, i = parse(str, i) + -- Set + res[key] = val + -- Next token + i = next_char(str, i, space_chars, true) + local chr = str:sub(i, i) + i = i + 1 + if chr == "}" then break end + if chr ~= "," then decode_error(str, i, "expected '}' or ','") end + end + return res, i end local char_func_map = { - [ '"' ] = parse_string, - [ "0" ] = parse_number, - [ "1" ] = parse_number, - [ "2" ] = parse_number, - [ "3" ] = parse_number, - [ "4" ] = parse_number, - [ "5" ] = parse_number, - [ "6" ] = parse_number, - [ "7" ] = parse_number, - [ "8" ] = parse_number, - [ "9" ] = parse_number, - [ "-" ] = parse_number, - [ "t" ] = parse_literal, - [ "f" ] = parse_literal, - [ "n" ] = parse_literal, - [ "[" ] = parse_array, - [ "{" ] = parse_object, + [ '"' ] = parse_string, + [ "0" ] = parse_number, + [ "1" ] = parse_number, + [ "2" ] = parse_number, + [ "3" ] = parse_number, + [ "4" ] = parse_number, + [ "5" ] = parse_number, + [ "6" ] = parse_number, + [ "7" ] = parse_number, + [ "8" ] = parse_number, + [ "9" ] = parse_number, + [ "-" ] = parse_number, + [ "t" ] = parse_literal, + [ "f" ] = parse_literal, + [ "n" ] = parse_literal, + [ "[" ] = parse_array, + [ "{" ] = parse_object, } parse = function(str, idx) - local chr = str:sub(idx, idx) - local f = char_func_map[chr] - if f then - return f(str, idx) - end - decode_error(str, idx, "unexpected character '" .. chr .. "'") + local chr = str:sub(idx, idx) + local f = char_func_map[chr] + if f then + return f(str, idx) + end + decode_error(str, idx, "unexpected character '" .. chr .. "'") end function json.decode(str) - if type(str) ~= "string" then - error("expected argument of type string, got " .. type(str)) - end - local res, idx = parse(str, next_char(str, 1, space_chars, true)) - idx = next_char(str, idx, space_chars, true) - if idx <= #str then - decode_error(str, idx, "trailing garbage") - end - return res + if type(str) ~= "string" then + error("expected argument of type string, got " .. type(str)) + end + local res, idx = parse(str, next_char(str, 1, space_chars, true)) + idx = next_char(str, idx, space_chars, true) + if idx <= #str then + decode_error(str, idx, "trailing garbage") + end + return res end