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copied!<p>The following functions uses some code from François Perrad's <code>lua-MessagePack</code>. A big thank you goes to him.</p> <pre><code>function float2hex (n) if n == 0.0 then return 0.0 end local sign = 0 if n < 0.0 then sign = 0x80 n = -n end local mant, expo = math.frexp(n) local hext = {} if mant ~= mant then hext[#hext+1] = string.char(0xFF, 0x88, 0x00, 0x00) elseif mant == math.huge or expo > 0x80 then if sign == 0 then hext[#hext+1] = string.char(0x7F, 0x80, 0x00, 0x00) else hext[#hext+1] = string.char(0xFF, 0x80, 0x00, 0x00) end elseif (mant == 0.0 and expo == 0) or expo < -0x7E then hext[#hext+1] = string.char(sign, 0x00, 0x00, 0x00) else expo = expo + 0x7E mant = (mant * 2.0 - 1.0) * math.ldexp(0.5, 24) hext[#hext+1] = string.char(sign + math.floor(expo / 0x2), (expo % 0x2) * 0x80 + math.floor(mant / 0x10000), math.floor(mant / 0x100) % 0x100, mant % 0x100) end return tonumber(string.gsub(table.concat(hext),"(.)", function (c) return string.format("%02X%s",string.byte(c),"") end), 16) end function hex2float (c) if c == 0 then return 0.0 end local c = string.gsub(string.format("%X", c),"(..)",function (x) return string.char(tonumber(x, 16)) end) local b1,b2,b3,b4 = string.byte(c, 1, 4) local sign = b1 > 0x7F local expo = (b1 % 0x80) * 0x2 + math.floor(b2 / 0x80) local mant = ((b2 % 0x80) * 0x100 + b3) * 0x100 + b4 if sign then sign = -1 else sign = 1 end local n if mant == 0 and expo == 0 then n = sign * 0.0 elseif expo == 0xFF then if mant == 0 then n = sign * math.huge else n = 0.0/0.0 end else n = sign * math.ldexp(1.0 + mant / 0x800000, expo - 0x7F) end return n end </code></pre>

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