Try to be more consistent about accepting denormalized float8 numbers.

On some platforms, strtod() reports ERANGE for a denormalized value (ie,
one that can be represented as distinct from zero, but is too small to have
full precision).  On others, it doesn't.  It seems better to try to accept
these values consistently, so add a test to see if the result value
indicates a true out-of-range condition.  This should be okay per Single
Unix Spec.  On machines where the underlying math isn't IEEE standard, the
behavior for such small numbers may not be very consistent, but then it
wouldn't be anyway.

Marti Raudsepp, after a proposal by Jeroen Vermeulen

diff --git a/src/backend/utils/adt/float.c b/src/backend/utils/adt/float.c
index 08434dc7ee4e185644dd0cf3d5e7f50a9d14d179..245030f531c532254966284b57f700ae49953938 100644 (file)
--- a/src/backend/utils/adt/float.c
+++ b/src/backend/utils/adt/float.c
@@ -217,6 +217,8 @@ float4in(PG_FUNCTION_ARGS)
        /* did we not see anything that looks like a double? */
        if (endptr == num || errno != 0)
        {
+               int             save_errno = errno;
+
                /*
                 * C99 requires that strtod() accept NaN and [-]Infinity, but not all
                 * platforms support that yet (and some accept them but set ERANGE
@@ -237,11 +239,21 @@ float4in(PG_FUNCTION_ARGS)
                        val = -get_float4_infinity();
                        endptr = num + 9;
                }
-               else if (errno == ERANGE)
-                       ereport(ERROR,
-                                       (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
-                                        errmsg("\"%s\" is out of range for type real",
-                                                       orig_num)));
+               else if (save_errno == ERANGE)
+               {
+                       /*
+                        * Some platforms return ERANGE for denormalized numbers (those
+                        * that are not zero, but are too close to zero to have full
+                        * precision).  We'd prefer not to throw error for that, so try
+                        * to detect whether it's a "real" out-of-range condition by
+                        * checking to see if the result is zero or huge.
+                        */
+                       if (val == 0.0 || val >= HUGE_VAL || val <= -HUGE_VAL)
+                               ereport(ERROR,
+                                               (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+                                                errmsg("\"%s\" is out of range for type real",
+                                                               orig_num)));
+               }
                else
                        ereport(ERROR,
                                        (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
@@ -410,6 +422,8 @@ float8in(PG_FUNCTION_ARGS)
        /* did we not see anything that looks like a double? */
        if (endptr == num || errno != 0)
        {
+               int             save_errno = errno;
+
                /*
                 * C99 requires that strtod() accept NaN and [-]Infinity, but not all
                 * platforms support that yet (and some accept them but set ERANGE
@@ -430,11 +444,21 @@ float8in(PG_FUNCTION_ARGS)
                        val = -get_float8_infinity();
                        endptr = num + 9;
                }
-               else if (errno == ERANGE)
-                       ereport(ERROR,
-                                       (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
-                                  errmsg("\"%s\" is out of range for type double precision",
-                                                 orig_num)));
+               else if (save_errno == ERANGE)
+               {
+                       /*
+                        * Some platforms return ERANGE for denormalized numbers (those
+                        * that are not zero, but are too close to zero to have full
+                        * precision).  We'd prefer not to throw error for that, so try
+                        * to detect whether it's a "real" out-of-range condition by
+                        * checking to see if the result is zero or huge.
+                        */
+                       if (val == 0.0 || val >= HUGE_VAL || val <= -HUGE_VAL)
+                               ereport(ERROR,
+                                               (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+                                                errmsg("\"%s\" is out of range for type double precision",
+                                                               orig_num)));
+               }
                else
                        ereport(ERROR,
                                        (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),