local sanitable = {
['\xfe'] = '\xf0';
['\1'] = '\xf1';
['\2'] = '\xf2';
['\3'] = '\xf3';
['\xf0'] = '\xfe';
['\xf1'] = '\1';
['\xf2'] = '\2';
['\xf3'] = '\3';
}
return {
capitalize = function(str)
return string.upper(string.sub(str, 1,1)) .. string.sub(str, 2)
end;
rand = function(min,max)
if not min then min = 16 end
if not max then max = min end
local str = ''
local r_int = 0x39 - 0x30
local r_upper = r_int + (0x5a - 0x41)
local r_lower = r_upper + (0x7a - 0x61)
for i = 1,math.random(max - min) + min do
-- 0x30 -- 0x39
-- 0x41 -- 0x5A
-- 0x61 -- 0x71
local codepoint = math.random(r_lower)
if codepoint > r_upper then
codepoint = (codepoint - r_upper) + 0x61
elseif codepoint > r_int then
codepoint = (codepoint - r_int) + 0x41
else
codepoint = codepoint + 0x30
end
str = str .. string.char(codepoint)
end
return str
end;
chop = function(str)
if string.sub(str, 1,1) == ' ' then
str = string.sub(str, 2)
end
if string.sub(str, #str,#str) == ' ' then
str = string.sub(str, 1, #str - 1)
end
return str
end;
meta_armor = function(str,mark_struct)
-- binary values stored in metadata need to be sanitized so
-- they don't contain values that will disrupt parsing of the
-- KV store, as minetest (stupidly) uses in-band signalling
local sanitized = string.gsub(str, '[\xfe\1\2\3]', function(char)
return '\xfe' .. sanitable[char]
end)
if sanitized ~= str and mark_struct then
-- use different type code to mark struct headers for
-- back-compat
return string.gsub(sanitized,'^\xfe\xf0\x99','\xfe\x98')
else return sanitized end
end;
meta_dearmor = function(str,cond)
local dearmor = function(s)
return string.gsub(s, '\xfe([\xf0\xf1\xf2\xf3])', function(char)
return sanitable[char]
end)
end
if cond then
if string.sub(str,1,2) == '\xfe\x98' then
return dearmor(string.gsub(str,'^\xfe\x98','\xfe\xf0\x99'))
else return str end
else return dearmor(str) end
end;
}