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Copy pathbit2float.sql
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209 lines (184 loc) · 5.37 KB
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/**
* @copyright (c) Kopex 2012
* @link git://github.com/Kopex/pgSql.git
* references http://babbage.cs.qc.cuny.edu/IEEE-754
*/
CREATE OR REPLACE FUNCTION bit32real(bit) RETURNS real
LANGUAGE plpgsql
AS $_$
declare
s int;
e int;
m int;
r real;
begin
if ($1>>31)::int THEN s=-1; else s=1;end if;
e = ($1<<1)::bit(8)::int;
if e=0 then m=(($1 & X'007fffff')<<1)::int;
else m=(($1 & X'007fffff')|X'00800000')::int;
end if;
e=e-127-23;
return s*m*pow(2,e);
end
$_$;
CREATE OR REPLACE FUNCTION real32bit(inp real) RETURNS bit
LANGUAGE plpgsql
AS $$
declare
BinVal bit[2102];Res bit[32];
znak bit;Result "bit";
intpart int;decpart real;
cnst CONSTANT int = 2102;
bias CONSTANT int = 1024;
index1 int;binexpnt int;b bit;index2 int;
begin
if inp = 0 then return 0::bit(32);end if;
if inp < 0 then znak=1; else znak=0; end if;
--convert and seperate input to integer and decimal parts
intpart = floor(abs(inp))::int;
decpart = abs(inp) - intpart;
--convert integer part
index1 = bias;
while(((intpart::real / 2) != 0) and (index1 >= 0)) loop
BinVal[index1] = (intpart % 2)::bit;
if (intpart % 2 = 0) then intpart = intpart / 2;
else intpart = floor(intpart::real / 2 - 0.5)::int;--???
end if;
index1= index1 - 1;
end loop;
--convert decimal part
index1 = bias + 1;
while ((decpart > 0) and (index1 < cnst)) loop
decpart = decpart * 2;
if (decpart >= 1) then
b = 1;
decpart = decpart-1;
else
b = 0;
end if;
BinVal[index1]=b;
index1 = index1 +1;
end loop;
--obtain exponent value
index1 = 0;
--find most significant bit of significand
while ((index1 < cnst) and (coalesce(BinVal[index1],0::bit) != 1::bit)) loop
index1 = index1+1; end loop;
binexpnt = bias - index1;
index1=index1+1;
For index2 in 1 .. 31 loop
if (index2 > 8) then
Res[index2] = coalesce(BinVal[index1],0::bit);
index2 =index2+1;
index1 =index1+1;
else
Res[index2] =0::bit;
end if;
IF (index1 = cnst) then exit; end if;
end loop;
--convert exponent value to binary representation
index1 = 8;
binexpnt = binexpnt+127;
while ((binexpnt::real / 2) != 0) loop
Res[index1] = binexpnt % 2;
if (binexpnt % 2 = 0) then binexpnt = binexpnt / 2;
else binexpnt = floor(binexpnt::real / 2 - 0.5)::int;
end if;
index1 = index1 - 1;
end loop;
Result=znak;
For index1 in 1 .. 31 loop
Result=Result||Res[index1];
end loop;
return Result;
end
$$;
CREATE OR REPLACE FUNCTION bit64real(bit) RETURNS double precision
LANGUAGE plpgsql
AS $_$
declare
s int;
e int;
m int8;
begin
if ($1>>63)::int8 THEN s=-1; else s=1;end if;
e = ($1<<1)::bit(11)::int;
if e=0 then m=(($1 & X'000fffffffffffff')<<1)::int8;
else m=(B'1'||(($1<<12)::bit(52)))::"bit"::int8;
end if;
e=e-1023-52;
return s*m*pow(2,e);
end
$_$;
CREATE OR REPLACE FUNCTION real64bit(inp double precision) RETURNS bit
LANGUAGE plpgsql
AS $$
declare
BinVal bit[2102];Res bit[64];
znak bit;Result "bit";
intpart int8;decpart float8;
cnst CONSTANT int = 2102;
bias CONSTANT int = 1024;
index1 int;binexpnt int;b bit;index2 int;
begin
--for index1 in 0 .. cnst loop BinVal[index1]=0; end loop;
if inp < 0 then znak=1; else znak=0; end if;
--convert and seperate input to integer and decimal parts
intpart = floor(abs(inp));
decpart = abs(inp) - intpart;
--convert integer part
index1 = bias;
while(((intpart::float8 / 2) != 0) and (index1 >= 0)) loop
BinVal[index1] = (intpart % 2)::bit;
if (intpart % 2 = 0) then intpart = intpart / 2;
else intpart = floor(intpart::float8 / 2 - 0.5)::int8;--???
end if;
index1= index1 - 1;
end loop;
--convert decimal part
index1 = bias + 1;
while ((decpart > 0) and (index1 < cnst)) loop
decpart = decpart * 2;
if (decpart >= 1) then
b = 1;
decpart = decpart-1;
else
b = 0;
end if;
BinVal[index1]=b;
index1 = index1 +1;
end loop;
--obtain exponent value
index1 = 0;
--find most significant bit of significand
while ((index1 < cnst) and (coalesce(BinVal[index1],0::bit) != 1::bit)) loop
index1 = index1+1; end loop;
binexpnt = bias - index1;
index1=index1+1;
For index2 in 1 .. 63 loop
if (index2 > 11) then
Res[index2] = coalesce(BinVal[index1],0::bit);
index2 =index2+1;
index1 =index1+1;
else
Res[index2] =0::bit;
end if;
IF (index1 = cnst) then exit; end if;
end loop;
--convert exponent value to binary representation
index1 = 11;--f64
binexpnt = binexpnt+1023;--f64
while ((binexpnt::float8 / 2) != 0) loop
Res[index1] = binexpnt % 2;
if (binexpnt % 2 = 0) then binexpnt = binexpnt / 2;
else binexpnt = floor(binexpnt::float8 / 2 - 0.5)::int8;
end if;
index1 = index1 - 1;
end loop;
Result=znak;
For index1 in 1 .. 63 loop
Result = Result||Res[index1];
end loop;
return Result;
end
$$;