Portability fixes and bug fixes for recent floating point input changes.

In particular, don't depend on strtod() to accept 'NaN' and 'Infinity'
inputs (while this is required by C99, not all platforms are compliant
with that yet). Also, don't require glibc's behavior from isinf():
it seems that on a lot of platforms isinf() does not itself distinguish
between negative and positive infinity.

src/backend/utils/adt/float.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/float.c,v 1.99 2004/03/12 00:25:40 neilc Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/float.c,v 1.100 2004/03/14 05:22:52 neilc Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -109,9 +109,30 @@ int			extra_float_digits = 0;		/* Added to DBL_DIG or FLT_DIG */
 
 static void CheckFloat4Val(double val);
 static void CheckFloat8Val(double val);
+static int	is_infinite(double val);
 static int	float4_cmp_internal(float4 a, float4 b);
 static int	float8_cmp_internal(float8 a, float8 b);
 
+/*
+ * Returns -1 if 'val' represents negative infinity, 1 if 'val'
+ * represents (positive) infinity, and 0 otherwise. On some platforms,
+ * this is equivalent to the isinf() macro, but not everywhere: C99
+ * does not specify that isinf() needs to distinguish between positive
+ * and negative infinity.
+ */
+static int
+is_infinite(double val)
+{
+	int inf = isinf(val);
+
+	if (inf == 0)
+		return 0;
+
+	if (val > 0)
+		return 1;
+
+	return -1;
+}
 
 /*
  * check to see if a float4 val is outside of the FLOAT4_MIN,
@@ -162,48 +183,78 @@ Datum
 float4in(PG_FUNCTION_ARGS)
 {
 	char	   *num = PG_GETARG_CSTRING(0);
+	char	   *orig_num;
 	double		val;
 	char	   *endptr;
 
+	/*
+	 * endptr points to the first character _after_ the sequence we
+	 * recognized as a valid floating point number. orig_num points to
+	 * the original input string.
+	 */
+	orig_num = num;
+
+	/*
+	 * Check for an empty-string input to begin with, to avoid
+	 * the vagaries of strtod() on different platforms.
+	 *
+	 * In releases prior to 7.5, we accepted an empty string as valid
+	 * input (yielding a float4 of 0). In 7.5, we accept empty
+	 * strings, but emit a warning noting that the feature is
+	 * deprecated. In 7.6+, the warning should be replaced by an
+	 * error.
+	 */
+	if (*num == '\0')
+	{
+		ereport(WARNING,
+				(errcode(ERRCODE_WARNING_DEPRECATED_FEATURE),
+				 errmsg("deprecated input syntax for type real: \"\""),
+				 errdetail("This input will be rejected in "
+						   "a future release of PostgreSQL.")));
+		PG_RETURN_FLOAT4((float4) 0.0);
+	}
+
+	/* skip leading whitespace */
+	while (*num != '\0' && isspace(*num))
+		num++;
+
 	errno = 0;
 	val = strtod(num, &endptr);
 
 	if (errno == ERANGE)
 		ereport(ERROR,
 				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
-				 errmsg("\"%s\" is out of range for type real", num)));
+				 errmsg("\"%s\" is out of range for type real",
+						orig_num)));
 
+	/* did we not see anything that looks like a double? */
 	if (num == endptr)
 	{
 		/*
-		 * We didn't find anything that looks like a float in the input
-		 *
-		 * In releases prior to 7.5, we accepted an empty string as
-		 * valid input (yielding a float8 of 0). In 7.5, we accept
-		 * empty strings, but emit a warning noting that the feature
-		 * is deprecated. In 7.6+, the warning should be replaced by
-		 * an error.
+		 * C99 requires that strtod() accept NaN and [-]Infinity, but
+		 * not all platforms support that yet. Therefore, we check for
+		 * these inputs ourselves.
 		 */
-		if (*num == '\0')
+		if (strncasecmp(num, "NaN", 3) == 0)
 		{
-			ereport(WARNING,
-					(errcode(ERRCODE_WARNING_DEPRECATED_FEATURE),
-					 errmsg("deprecated input syntax for type real: \"\""),
-					 errdetail("This input will be rejected in "
-							   "a future release of PostgreSQL.")));
-			Assert(val == 0.0);
-		}
-		else if (strcasecmp(num, "NaN") == 0)
 			val = NAN;
-		else if (strcasecmp(num, "Infinity") == 0)
+			endptr = num + 3;
+		}
+		else if (strncasecmp(num, "Infinity", 8) == 0)
+		{
 			val = HUGE_VAL;
-		else if (strcasecmp(num, "-Infinity") == 0)
+			endptr = num + 8;
+		}
+		else if (strncasecmp(num, "-Infinity", 9) == 0)
+		{
 			val = -HUGE_VAL;
+			endptr = num + 9;
+		}
 		else
 			ereport(ERROR,
 					(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
 					 errmsg("invalid input syntax for type real: \"%s\"",
-							num)));
+							orig_num)));
 	}
 
 	/* skip trailing whitespace */
@@ -215,11 +266,11 @@ float4in(PG_FUNCTION_ARGS)
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
 				 errmsg("invalid input syntax for type real: \"%s\"",
-						num)));
+						orig_num)));
 
 	/*
 	 * if we get here, we have a legal double, still need to check to see
-	 * if it's a legal float
+	 * if it's a legal float4
 	 */
 	if (!isinf(val))
 		CheckFloat4Val(val);
@@ -236,22 +287,27 @@ float4out(PG_FUNCTION_ARGS)
 {
 	float4		num = PG_GETARG_FLOAT4(0);
 	char	   *ascii = (char *) palloc(MAXFLOATWIDTH + 1);
-	int			infflag;
-	int			ndig;
 
 	if (isnan(num))
 		PG_RETURN_CSTRING(strcpy(ascii, "NaN"));
-	infflag = isinf(num);
-	if (infflag > 0)
-		PG_RETURN_CSTRING(strcpy(ascii, "Infinity"));
-	if (infflag < 0)
-		PG_RETURN_CSTRING(strcpy(ascii, "-Infinity"));
 
-	ndig = FLT_DIG + extra_float_digits;
-	if (ndig < 1)
-		ndig = 1;
+	switch (is_infinite(num))
+	{
+		case 1:
+			strcpy(ascii, "Infinity");
+			break;
+		case -1:
+			strcpy(ascii, "-Infinity");
+			break;
+		default:
+		{
+			int ndig = FLT_DIG + extra_float_digits;
+			if (ndig < 1)
+				ndig = 1;
 
-	sprintf(ascii, "%.*g", ndig, num);
+			sprintf(ascii, "%.*g", ndig, num);
+		}
+	}
 
 	PG_RETURN_CSTRING(ascii);
 }
@@ -292,48 +348,78 @@ Datum
 float8in(PG_FUNCTION_ARGS)
 {
 	char	   *num = PG_GETARG_CSTRING(0);
+	char	   *orig_num;
 	double		val;
 	char	   *endptr;
 
+	/*
+	 * endptr points to the first character _after_ the sequence we
+	 * recognized as a valid floating point number. orig_num points to
+	 * the original input string.
+	 */
+	orig_num = num;
+
+	/*
+	 * Check for an empty-string input to begin with, to avoid
+	 * the vagaries of strtod() on different platforms.
+	 *
+	 * In releases prior to 7.5, we accepted an empty string as valid
+	 * input (yielding a float8 of 0). In 7.5, we accept empty
+	 * strings, but emit a warning noting that the feature is
+	 * deprecated. In 7.6+, the warning should be replaced by an
+	 * error.
+	 */
+	if (*num == '\0')
+	{
+		ereport(WARNING,
+				(errcode(ERRCODE_WARNING_DEPRECATED_FEATURE),
+				 errmsg("deprecated input syntax for type double precision: \"\""),
+				 errdetail("This input will be rejected in "
+						   "a future release of PostgreSQL.")));
+		PG_RETURN_FLOAT8(0.0);
+	}
+
+	/* skip leading whitespace */
+	while (*num != '\0' && isspace(*num))
+		num++;
+
 	errno = 0;
 	val = strtod(num, &endptr);
 
 	if (errno == ERANGE)
 		ereport(ERROR,
 				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
-				 errmsg("\"%s\" is out of range for type double precision", num)));
+				 errmsg("\"%s\" is out of range for type double precision",
+						orig_num)));
 
+	/* did we not see anything that looks like a double? */
 	if (num == endptr)
 	{
 		/*
-		 * We didn't find anything that looks like a float in the input
-		 *
-		 * In releases prior to 7.5, we accepted an empty string as
-		 * valid input (yielding a float8 of 0). In 7.5, we accept
-		 * empty strings, but emit a warning noting that the feature
-		 * is deprecated. In 7.6+, the warning should be replaced by
-		 * an error.
+		 * C99 requires that strtod() accept NaN and [-]Infinity, but
+		 * not all platforms support that yet. Therefore, we check for
+		 * these inputs ourselves.
 		 */
-		if (*num == '\0')
+		if (strncasecmp(num, "NaN", 3) == 0)
 		{
-			ereport(WARNING,
-					(errcode(ERRCODE_WARNING_DEPRECATED_FEATURE),
-					 errmsg("deprecated input syntax for type double precision: \"\""),
-					 errdetail("This input will be rejected in "
-							   "a future release of PostgreSQL.")));
-			Assert(val == 0.0);
-		}
-		else if (strcasecmp(num, "NaN") == 0)
 			val = NAN;
-		else if (strcasecmp(num, "Infinity") == 0)
+			endptr = num + 3;
+		}
+		else if (strncasecmp(num, "Infinity", 8) == 0)
+		{
 			val = HUGE_VAL;
-		else if (strcasecmp(num, "-Infinity") == 0)
+			endptr = num + 8;
+		}
+		else if (strncasecmp(num, "-Infinity", 9) == 0)
+		{
 			val = -HUGE_VAL;
+			endptr = num + 9;
+		}
 		else
 			ereport(ERROR,
 					(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
 					 errmsg("invalid input syntax for type double precision: \"%s\"",
-							num)));
+							orig_num)));
 	}
 
 	/* skip trailing whitespace */
@@ -345,7 +431,7 @@ float8in(PG_FUNCTION_ARGS)
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
 				 errmsg("invalid input syntax for type double precision: \"%s\"",
-						num)));
+						orig_num)));
 
 	if (!isinf(val))
 		CheckFloat8Val(val);
@@ -362,22 +448,27 @@ float8out(PG_FUNCTION_ARGS)
 {
 	float8		num = PG_GETARG_FLOAT8(0);
 	char	   *ascii = (char *) palloc(MAXDOUBLEWIDTH + 1);
-	int			infflag;
-	int			ndig;
 
 	if (isnan(num))
 		PG_RETURN_CSTRING(strcpy(ascii, "NaN"));
-	infflag = isinf(num);
-	if (infflag > 0)
-		PG_RETURN_CSTRING(strcpy(ascii, "Infinity"));
-	if (infflag < 0)
-		PG_RETURN_CSTRING(strcpy(ascii, "-Infinity"));
 
-	ndig = DBL_DIG + extra_float_digits;
-	if (ndig < 1)
-		ndig = 1;
+	switch (is_infinite(num))
+	{
+		case 1:
+			strcpy(ascii, "Infinity");
+			break;
+		case -1:
+			strcpy(ascii, "-Infinity");
+			break;
+		default:
+		{
+			int ndig = DBL_DIG + extra_float_digits;
+			if (ndig < 1)
+				ndig = 1;
 
-	sprintf(ascii, "%.*g", ndig, num);
+			sprintf(ascii, "%.*g", ndig, num);
+		}
+	}
 
 	PG_RETURN_CSTRING(ascii);
 }