Move scanint8() to numutils.c

Move scanint8() to numutils.c and rename to pg_strtoint64().  We
already have a "16" and "32" version of that, and the code inside the
functions was aligned, so this move makes all three versions
consistent.  The API is also changed to no longer provide the errorOK
case.  Users that need the error checking can use strtoi64().

Reviewed-by: John Naylor <john.naylor@enterprisedb.com>
Discussion: https://www.postgresql.org/message-id/flat/b239564c-cad0-b23e-c57e-166d883cb97d@enterprisedb.com

1 files changed, 84 insertions, 0 deletions

diff --git a/src/backend/utils/adt/numutils.c b/src/backend/utils/adt/numutils.c
index 898a9e3f9a1..e82d23a325e 100644
--- a/src/backend/utils/adt/numutils.c
+++ b/src/backend/utils/adt/numutils.c
@@ -326,6 +326,90 @@ invalid_syntax:
 }
 
 /*
+ * Convert input string to a signed 64 bit integer.
+ *
+ * Allows any number of leading or trailing whitespace characters. Will throw
+ * ereport() upon bad input format or overflow.
+ *
+ * NB: Accumulate input as a negative number, to deal with two's complement
+ * representation of the most negative number, which can't be represented as a
+ * positive number.
+ */
+int64
+pg_strtoint64(const char *s)
+{
+	const char *ptr = s;
+	int64		tmp = 0;
+	bool		neg = false;
+
+	/*
+	 * Do our own scan, rather than relying on sscanf which might be broken
+	 * for long long.
+	 *
+	 * As INT64_MIN can't be stored as a positive 64 bit integer, accumulate
+	 * value as a negative number.
+	 */
+
+	/* skip leading spaces */
+	while (*ptr && isspace((unsigned char) *ptr))
+		ptr++;
+
+	/* handle sign */
+	if (*ptr == '-')
+	{
+		ptr++;
+		neg = true;
+	}
+	else if (*ptr == '+')
+		ptr++;
+
+	/* require at least one digit */
+	if (unlikely(!isdigit((unsigned char) *ptr)))
+		goto invalid_syntax;
+
+	/* process digits */
+	while (*ptr && isdigit((unsigned char) *ptr))
+	{
+		int8		digit = (*ptr++ - '0');
+
+		if (unlikely(pg_mul_s64_overflow(tmp, 10, &tmp)) ||
+			unlikely(pg_sub_s64_overflow(tmp, digit, &tmp)))
+			goto out_of_range;
+	}
+
+	/* allow trailing whitespace, but not other trailing chars */
+	while (*ptr != '\0' && isspace((unsigned char) *ptr))
+		ptr++;
+
+	if (unlikely(*ptr != '\0'))
+		goto invalid_syntax;
+
+	if (!neg)
+	{
+		/* could fail if input is most negative number */
+		if (unlikely(tmp == PG_INT64_MIN))
+			goto out_of_range;
+		tmp = -tmp;
+	}
+
+	return tmp;
+
+out_of_range:
+	ereport(ERROR,
+			(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+			 errmsg("value \"%s\" is out of range for type %s",
+					s, "bigint")));
+
+invalid_syntax:
+	ereport(ERROR,
+			(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
+			 errmsg("invalid input syntax for type %s: \"%s\"",
+					"bigint", s)));
+
+	return 0;					/* keep compiler quiet */
+}
+
+/*
  * pg_itoa: converts a signed 16-bit integer to its string representation
  * and returns strlen(a).
  *