diff options
Diffstat (limited to 'src/backend/utils/adt/float.c')
| -rw-r--r-- | src/backend/utils/adt/float.c | 59 |
1 files changed, 52 insertions, 7 deletions
diff --git a/src/backend/utils/adt/float.c b/src/backend/utils/adt/float.c index 51e996ceb2a..4bad17efe77 100644 --- a/src/backend/utils/adt/float.c +++ b/src/backend/utils/adt/float.c @@ -31,6 +31,9 @@ #define M_PI 3.14159265358979323846 #endif +/* Radians per degree, a.k.a. PI / 180 */ +#define RADIANS_PER_DEGREE 0.0174532925199432957692 + /* Visual C++ etc lacks NAN, and won't accept 0.0/0.0. NAN definition from * http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vclang/html/vclrfNotNumberNANItems.asp */ @@ -1919,7 +1922,7 @@ datan2d(PG_FUNCTION_ARGS) static double sind_0_to_30(double x) { - return (sin(x * (M_PI / 180.0)) / sin(30.0 * (M_PI / 180.0))) / 2.0; + return (sin(x * RADIANS_PER_DEGREE) / sin(30.0 * RADIANS_PER_DEGREE)) / 2.0; } @@ -1931,8 +1934,8 @@ sind_0_to_30(double x) static double cosd_0_to_60(double x) { - return 1.0 - ((1.0 - cos(x * (M_PI / 180.0))) / - (1.0 - cos(60.0 * (M_PI / 180.0)))) / 2.0; + return 1.0 - ((1.0 - cos(x * RADIANS_PER_DEGREE)) / + (1.0 - cos(60.0 * RADIANS_PER_DEGREE))) / 2.0; } @@ -2030,8 +2033,9 @@ Datum dcotd(PG_FUNCTION_ARGS) { float8 arg1 = PG_GETARG_FLOAT8(0); - int sign = 1; float8 result; + int sign = 1; + static float8 cot45 = 0.0; /* * Per the POSIX spec, return NaN if the input is NaN and throw an error @@ -2071,6 +2075,26 @@ dcotd(PG_FUNCTION_ARGS) result = sign * cosd_q1(arg1) / sind_q1(arg1); + /* + * We want cotd(45) to be exactly 1, but the above computation might've + * produced something different, so scale to get the right result. To + * avoid redoing cosd_q1(45) / sind_q1(45) many times, and to prevent the + * compiler from maybe rearranging the calculation, cache that value in a + * static variable. + */ + if (cot45 == 0.0) + cot45 = cosd_q1(45.0) / sind_q1(45.0); + + result /= cot45; + + /* + * On some machines, we get cotd(270) = minus zero, but this isn't always + * true. For portability, and because the user constituency for this + * function probably doesn't want minus zero, force it to plain zero. + */ + if (result == 0.0) + result = 0.0; + CHECKFLOATVAL(result, true /* cotd(0) == Inf */ , true); PG_RETURN_FLOAT8(result); } @@ -2133,8 +2157,9 @@ Datum dtand(PG_FUNCTION_ARGS) { float8 arg1 = PG_GETARG_FLOAT8(0); - int sign = 1; float8 result; + int sign = 1; + static float8 tan45 = 0.0; /* * Per the POSIX spec, return NaN if the input is NaN and throw an error @@ -2174,6 +2199,26 @@ dtand(PG_FUNCTION_ARGS) result = sign * sind_q1(arg1) / cosd_q1(arg1); + /* + * We want tand(45) to be exactly 1, but the above computation might've + * produced something different, so scale to get the right result. To + * avoid redoing sind_q1(45) / cosd_q1(45) many times, and to prevent the + * compiler from maybe rearranging the calculation, cache that value in a + * static variable. + */ + if (tan45 == 0.0) + tan45 = sind_q1(45.0) / cosd_q1(45.0); + + result /= tan45; + + /* + * On some machines, we get tand(180) = minus zero, but this isn't always + * true. For portability, and because the user constituency for this + * function probably doesn't want minus zero, force it to plain zero. + */ + if (result == 0.0) + result = 0.0; + CHECKFLOATVAL(result, true /* tand(90) == Inf */ , true); PG_RETURN_FLOAT8(result); } @@ -2188,7 +2233,7 @@ degrees(PG_FUNCTION_ARGS) float8 arg1 = PG_GETARG_FLOAT8(0); float8 result; - result = arg1 * (180.0 / M_PI); + result = arg1 / RADIANS_PER_DEGREE; CHECKFLOATVAL(result, isinf(arg1), arg1 == 0); PG_RETURN_FLOAT8(result); @@ -2214,7 +2259,7 @@ radians(PG_FUNCTION_ARGS) float8 arg1 = PG_GETARG_FLOAT8(0); float8 result; - result = arg1 * (M_PI / 180.0); + result = arg1 * RADIANS_PER_DEGREE; CHECKFLOATVAL(result, isinf(arg1), arg1 == 0); PG_RETURN_FLOAT8(result); |