Re: [Tarantool-patches] [PATCH v5 47/52] sql: introduce mem_get_double()

[Mergen Imeev via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

Thank you for the review! My answer, diff and new patch below. New patch also
includes some changes in vdbe.c - previously I missed some code there, which
worked directly with mem->u.r.

On Wed, Apr 14, 2021 at 01:04:36AM +0200, Vladislav Shpilevoy wrote:
> The same as for the previous getters. The result is ignored in 100%
> cases. Therefore it must be called 'unsafe', and return the double
> as 'return'. When fails, it can return 0, so as at least the behaviour
> is not undefined. The same '0 on error' could be used in the other
> getters.
Added mem_get_double_unsafe().


Diff:


diff --git a/src/box/sql/date.c b/src/box/sql/date.c
index dffc23616..dbf460498 100644
--- a/src/box/sql/date.c
+++ b/src/box/sql/date.c
@@ -929,7 +929,7 @@ isDate(sql_context * context, int argc, sql_value ** argv, DateTime * p)
 	}
 	if ((eType = sql_value_type(argv[0])) == MP_DOUBLE
 	    || eType == MP_INT) {
-		setRawDateNumber(p, sql_value_double(argv[0]));
+		setRawDateNumber(p, mem_get_double_unsafe(argv[0]));
 	} else {
 		z = sql_value_text(argv[0]);
 		if (!z || parseDateOrTime(context, (char *)z, p)) {
diff --git a/src/box/sql/func.c b/src/box/sql/func.c
index 97a2f5bb0..dbf899c02 100644
--- a/src/box/sql/func.c
+++ b/src/box/sql/func.c
@@ -229,9 +229,7 @@ absFunc(sql_context * context, int argc, sql_value ** argv)
 			 * Abs(X) returns 0.0 if X is a string or blob
 			 * that cannot be converted to a numeric value.
 			 */
-			double rVal;
-			if (mem_get_double(argv[0], &rVal) != 0)
-				rVal = 0;
+			double rVal = mem_get_double_unsafe(argv[0]);
 			if (rVal < 0)
 				rVal = -rVal;
 			sql_result_double(context, rVal);
@@ -544,7 +542,7 @@ roundFunc(sql_context * context, int argc, sql_value ** argv)
 		context->is_aborted = true;
 		return;
 	}
-	mem_get_double(argv[0], &r);
+	r = mem_get_double_unsafe(argv[0]);
 	/* If Y==0 and X will fit in a 64-bit int,
 	 * handle the rounding directly,
 	 * otherwise use printf.
@@ -1050,7 +1048,7 @@ quoteFunc(sql_context * context, int argc, sql_value ** argv)
 	case MP_DOUBLE:{
 			double r1, r2;
 			char zBuf[50];
-			mem_get_double(argv[0], &r1);
+			r1 = mem_get_double_unsafe(argv[0]);
 			sql_snprintf(sizeof(zBuf), zBuf, "%!.15g", r1);
 			sqlAtoF(zBuf, &r2, 20);
 			if (r1 != r2) {
@@ -1663,9 +1661,7 @@ sum_step(struct sql_context *context, int argc, sql_value **argv)
 			p->overflow = 1;
 		}
 	} else {
-		double d;
-		mem_get_double(argv[0], &d);
-		p->rSum += d;
+		p->rSum += mem_get_double_unsafe(argv[0]);
 		p->approx = 1;
 	}
 }
diff --git a/src/box/sql/mem.h b/src/box/sql/mem.h
index d1c3ec386..d7ffa3444 100644
--- a/src/box/sql/mem.h
+++ b/src/box/sql/mem.h
@@ -796,6 +796,20 @@ mem_get_uint_unsafe(const struct Mem *mem)
 int
 mem_get_double(const struct Mem *mem, double *d);
 
+/**
+ * Return value of MEM converted to double. This function is not safe since
+ * there is no proper processing in case mem_get_double() return an error. In
+ * this case this functions returns 0.
+ */
+static inline double
+mem_get_double_unsafe(const struct Mem *mem)
+{
+	double d;
+	if (mem_get_double(mem, &d) != 0)
+		return 0.;
+	return d;
+}
+
 /**
  * Simple type to str convertor. It is used to simplify
  * error reporting.
diff --git a/src/box/sql/printf.c b/src/box/sql/printf.c
index 97df8af35..2f1948ff8 100644
--- a/src/box/sql/printf.c
+++ b/src/box/sql/printf.c
@@ -152,9 +152,7 @@ getDoubleArg(PrintfArguments * p)
 {
 	if (p->nArg <= p->nUsed)
 		return 0.0;
-	double d;
-	mem_get_double(p->apArg[p->nUsed++], &d);
-	return d;
+	return mem_get_double_unsafe(p->apArg[p->nUsed++]);
 }
 
 static char *
diff --git a/src/box/sql/vdbe.c b/src/box/sql/vdbe.c
index f7b6df0d9..1deb8e507 100644
--- a/src/box/sql/vdbe.c
+++ b/src/box/sql/vdbe.c
@@ -2751,24 +2751,22 @@ case OP_SeekGT: {       /* jump, in3 */
 		if (mem_is_str(pIn3))
 			mem_to_number(pIn3);
 		int64_t i;
-		if (mem_is_uint(pIn3)) {
-			i = pIn3->u.u;
-			is_neg = false;
-		} else if (mem_is_nint(pIn3)) {
-			i = pIn3->u.i;
-			is_neg = true;
-		} else if (mem_is_double(pIn3)) {
-			if (pIn3->u.r > (double)INT64_MAX)
+		if (mem_get_int(pIn3, &i, &is_neg) != 0) {
+			if (!mem_is_double(pIn3)) {
+				diag_set(ClientError, ER_SQL_TYPE_MISMATCH,
+					 mem_str(pIn3), "integer");
+				goto abort_due_to_error;
+			}
+			double d = mem_get_double_unsafe(pIn3);
+			assert(d >= (double)INT64_MAX || d < (double)INT64_MIN);
+			/* TODO: add [INT64_MAX, UINT64_MAX) here. */
+			if (d > (double)INT64_MAX)
 				i = INT64_MAX;
-			else if (pIn3->u.r < (double)INT64_MIN)
+			else if (d < (double)INT64_MIN)
 				i = INT64_MIN;
 			else
-				i = pIn3->u.r;
+				i = d;
 			is_neg = i < 0;
-		} else {
-			diag_set(ClientError, ER_SQL_TYPE_MISMATCH,
-				 mem_str(pIn3), "integer");
-			goto abort_due_to_error;
 		}
 		iKey = i;
 
@@ -2791,7 +2789,7 @@ case OP_SeekGT: {       /* jump, in3 */
 			 *        (x >  4.9)    ->     (x >= 5)
 			 *        (x <= 4.9)    ->     (x <  5)
 			 */
-			if (pIn3->u.r<(double)iKey) {
+			if (mem_get_double_unsafe(pIn3) < (double)iKey) {
 				assert(OP_SeekGE==(OP_SeekGT-1));
 				assert(OP_SeekLT==(OP_SeekLE-1));
 				assert((OP_SeekLE & 0x0001)==(OP_SeekGT & 0x0001));
@@ -2801,7 +2799,7 @@ case OP_SeekGT: {       /* jump, in3 */
 			/* If the approximation iKey is smaller than the actual real search
 			 * term, substitute <= for < and > for >=.
 			 */
-			else if (pIn3->u.r>(double)iKey) {
+			else if (mem_get_double_unsafe(pIn3) > (double)iKey) {
 				assert(OP_SeekLE==(OP_SeekLT+1));
 				assert(OP_SeekGT==(OP_SeekGE+1));
 				assert((OP_SeekLT & 0x0001)==(OP_SeekGE & 0x0001));



New patch:


commit a007a336371b86c7327db12388f58ee55a511d98
Author: Mergen Imeev <imeevma@gmail.com>
Date:   Wed Mar 17 14:13:30 2021 +0300

    sql: introduce mem_get_double()
    
    This patch introduces mem_get_double(). This function is used to receive
    double value from MEM. If value of MEM is not double, it is converted to
    double if possible. MEM is not changed.
    
    Part of #5818

diff --git a/src/box/sql/date.c b/src/box/sql/date.c
index dffc23616..dbf460498 100644
--- a/src/box/sql/date.c
+++ b/src/box/sql/date.c
@@ -929,7 +929,7 @@ isDate(sql_context * context, int argc, sql_value ** argv, DateTime * p)
 	}
 	if ((eType = sql_value_type(argv[0])) == MP_DOUBLE
 	    || eType == MP_INT) {
-		setRawDateNumber(p, sql_value_double(argv[0]));
+		setRawDateNumber(p, mem_get_double_unsafe(argv[0]));
 	} else {
 		z = sql_value_text(argv[0]);
 		if (!z || parseDateOrTime(context, (char *)z, p)) {
diff --git a/src/box/sql/func.c b/src/box/sql/func.c
index 5503a9b16..dbf899c02 100644
--- a/src/box/sql/func.c
+++ b/src/box/sql/func.c
@@ -225,12 +225,11 @@ absFunc(sql_context * context, int argc, sql_value ** argv)
 		return;
 	}
 	default:{
-			/* Because sql_value_double() returns 0.0 if the argument is not
-			 * something that can be converted into a number, we have:
-			 * IMP: R-01992-00519 Abs(X) returns 0.0 if X is a string or blob
+			/*
+			 * Abs(X) returns 0.0 if X is a string or blob
 			 * that cannot be converted to a numeric value.
 			 */
-			double rVal = sql_value_double(argv[0]);
+			double rVal = mem_get_double_unsafe(argv[0]);
 			if (rVal < 0)
 				rVal = -rVal;
 			sql_result_double(context, rVal);
@@ -543,7 +542,7 @@ roundFunc(sql_context * context, int argc, sql_value ** argv)
 		context->is_aborted = true;
 		return;
 	}
-	r = sql_value_double(argv[0]);
+	r = mem_get_double_unsafe(argv[0]);
 	/* If Y==0 and X will fit in a 64-bit int,
 	 * handle the rounding directly,
 	 * otherwise use printf.
@@ -1049,7 +1048,7 @@ quoteFunc(sql_context * context, int argc, sql_value ** argv)
 	case MP_DOUBLE:{
 			double r1, r2;
 			char zBuf[50];
-			r1 = sql_value_double(argv[0]);
+			r1 = mem_get_double_unsafe(argv[0]);
 			sql_snprintf(sizeof(zBuf), zBuf, "%!.15g", r1);
 			sqlAtoF(zBuf, &r2, 20);
 			if (r1 != r2) {
@@ -1662,7 +1661,7 @@ sum_step(struct sql_context *context, int argc, sql_value **argv)
 			p->overflow = 1;
 		}
 	} else {
-		p->rSum += sql_value_double(argv[0]);
+		p->rSum += mem_get_double_unsafe(argv[0]);
 		p->approx = 1;
 	}
 }
diff --git a/src/box/sql/mem.c b/src/box/sql/mem.c
index ab31029df..764735322 100644
--- a/src/box/sql/mem.c
+++ b/src/box/sql/mem.c
@@ -1101,6 +1101,29 @@ mem_get_uint(const struct Mem *mem, uint64_t *u)
 	return -1;
 }
 
+int
+mem_get_double(const struct Mem *mem, double *d)
+{
+	if ((mem->flags & MEM_Real) != 0) {
+		*d = mem->u.r;
+		return 0;
+	}
+	if ((mem->flags & MEM_Int) != 0) {
+		*d = (double)mem->u.i;
+		return 0;
+	}
+	if ((mem->flags & MEM_UInt) != 0) {
+		*d = (double)mem->u.u;
+		return 0;
+	}
+	if ((mem->flags & MEM_Str) != 0) {
+		if (sqlAtoF(mem->z, d, mem->n) == 0)
+			return -1;
+		return 0;
+	}
+	return -1;
+}
+
 int
 mem_copy(struct Mem *to, const struct Mem *from)
 {
@@ -2240,32 +2263,6 @@ mem_value_bool(const struct Mem *mem, bool *b)
 	return -1;
 }
 
-/*
- * Return the best representation of pMem that we can get into a
- * double.  If pMem is already a double or an integer, return its
- * value.  If it is a string or blob, try to convert it to a double.
- * If it is a NULL, return 0.0.
- */
-int
-sqlVdbeRealValue(Mem * pMem, double *v)
-{
-	assert(EIGHT_BYTE_ALIGNMENT(pMem));
-	if (pMem->flags & MEM_Real) {
-		*v = pMem->u.r;
-		return 0;
-	} else if (pMem->flags & MEM_Int) {
-		*v = (double)pMem->u.i;
-		return 0;
-	} else if ((pMem->flags & MEM_UInt) != 0) {
-		*v = (double)pMem->u.u;
-		return 0;
-	} else if (pMem->flags & MEM_Str) {
-		if (sqlAtoF(pMem->z, v, pMem->n))
-			return 0;
-	}
-	return -1;
-}
-
 /**************************** sql_value_  ******************************
  * The following routines extract information from a Mem or sql_value
  * structure.
@@ -2292,14 +2289,6 @@ sql_value_bytes(sql_value * pVal)
 	return sqlValueBytes(pVal);
 }
 
-double
-sql_value_double(sql_value * pVal)
-{
-	double v = 0.0;
-	sqlVdbeRealValue((Mem *) pVal, &v);
-	return v;
-}
-
 bool
 sql_value_boolean(sql_value *val)
 {
diff --git a/src/box/sql/mem.h b/src/box/sql/mem.h
index ca8a75b50..d7ffa3444 100644
--- a/src/box/sql/mem.h
+++ b/src/box/sql/mem.h
@@ -788,6 +788,28 @@ mem_get_uint_unsafe(const struct Mem *mem)
 	return u;
 }
 
+/**
+ * Return value for MEM of DOUBLE type. For MEM of all other types convert
+ * value of the MEM to DOUBLE if possible and return converted value. Original
+ * MEM is not changed.
+ */
+int
+mem_get_double(const struct Mem *mem, double *d);
+
+/**
+ * Return value of MEM converted to double. This function is not safe since
+ * there is no proper processing in case mem_get_double() return an error. In
+ * this case this functions returns 0.
+ */
+static inline double
+mem_get_double_unsafe(const struct Mem *mem)
+{
+	double d;
+	if (mem_get_double(mem, &d) != 0)
+		return 0.;
+	return d;
+}
+
 /**
  * Simple type to str convertor. It is used to simplify
  * error reporting.
@@ -842,16 +864,12 @@ releaseMemArray(Mem * p, int N);
 
 int
 mem_value_bool(const struct Mem *mem, bool *b);
-int sqlVdbeRealValue(struct Mem *, double *);
 const void *
 sql_value_blob(struct Mem *);
 
 int
 sql_value_bytes(struct Mem *);
 
-double
-sql_value_double(struct Mem *);
-
 bool
 sql_value_boolean(struct Mem *val);
 
diff --git a/src/box/sql/printf.c b/src/box/sql/printf.c
index eb8413f9c..2f1948ff8 100644
--- a/src/box/sql/printf.c
+++ b/src/box/sql/printf.c
@@ -152,7 +152,7 @@ getDoubleArg(PrintfArguments * p)
 {
 	if (p->nArg <= p->nUsed)
 		return 0.0;
-	return sql_value_double(p->apArg[p->nUsed++]);
+	return mem_get_double_unsafe(p->apArg[p->nUsed++]);
 }
 
 static char *
diff --git a/src/box/sql/sqlInt.h b/src/box/sql/sqlInt.h
index 6ead9b261..3f6fa1722 100644
--- a/src/box/sql/sqlInt.h
+++ b/src/box/sql/sqlInt.h
@@ -442,9 +442,6 @@ sql_column_bytes(sql_stmt *, int iCol);
 int
 sql_column_bytes16(sql_stmt *, int iCol);
 
-double
-sql_column_double(sql_stmt *, int iCol);
-
 bool
 sql_column_boolean(struct sql_stmt *stmt, int column);
 
diff --git a/src/box/sql/vdbe.c b/src/box/sql/vdbe.c
index f7b6df0d9..1deb8e507 100644
--- a/src/box/sql/vdbe.c
+++ b/src/box/sql/vdbe.c
@@ -2751,24 +2751,22 @@ case OP_SeekGT: {       /* jump, in3 */
 		if (mem_is_str(pIn3))
 			mem_to_number(pIn3);
 		int64_t i;
-		if (mem_is_uint(pIn3)) {
-			i = pIn3->u.u;
-			is_neg = false;
-		} else if (mem_is_nint(pIn3)) {
-			i = pIn3->u.i;
-			is_neg = true;
-		} else if (mem_is_double(pIn3)) {
-			if (pIn3->u.r > (double)INT64_MAX)
+		if (mem_get_int(pIn3, &i, &is_neg) != 0) {
+			if (!mem_is_double(pIn3)) {
+				diag_set(ClientError, ER_SQL_TYPE_MISMATCH,
+					 mem_str(pIn3), "integer");
+				goto abort_due_to_error;
+			}
+			double d = mem_get_double_unsafe(pIn3);
+			assert(d >= (double)INT64_MAX || d < (double)INT64_MIN);
+			/* TODO: add [INT64_MAX, UINT64_MAX) here. */
+			if (d > (double)INT64_MAX)
 				i = INT64_MAX;
-			else if (pIn3->u.r < (double)INT64_MIN)
+			else if (d < (double)INT64_MIN)
 				i = INT64_MIN;
 			else
-				i = pIn3->u.r;
+				i = d;
 			is_neg = i < 0;
-		} else {
-			diag_set(ClientError, ER_SQL_TYPE_MISMATCH,
-				 mem_str(pIn3), "integer");
-			goto abort_due_to_error;
 		}
 		iKey = i;
 
@@ -2791,7 +2789,7 @@ case OP_SeekGT: {       /* jump, in3 */
 			 *        (x >  4.9)    ->     (x >= 5)
 			 *        (x <= 4.9)    ->     (x <  5)
 			 */
-			if (pIn3->u.r<(double)iKey) {
+			if (mem_get_double_unsafe(pIn3) < (double)iKey) {
 				assert(OP_SeekGE==(OP_SeekGT-1));
 				assert(OP_SeekLT==(OP_SeekLE-1));
 				assert((OP_SeekLE & 0x0001)==(OP_SeekGT & 0x0001));
@@ -2801,7 +2799,7 @@ case OP_SeekGT: {       /* jump, in3 */
 			/* If the approximation iKey is smaller than the actual real search
 			 * term, substitute <= for < and > for >=.
 			 */
-			else if (pIn3->u.r>(double)iKey) {
+			else if (mem_get_double_unsafe(pIn3) > (double)iKey) {
 				assert(OP_SeekLE==(OP_SeekLT+1));
 				assert(OP_SeekGT==(OP_SeekGE+1));
 				assert((OP_SeekLT & 0x0001)==(OP_SeekGE & 0x0001));
diff --git a/src/box/sql/vdbeapi.c b/src/box/sql/vdbeapi.c
index 1126425bc..daa5e0809 100644
--- a/src/box/sql/vdbeapi.c
+++ b/src/box/sql/vdbeapi.c
@@ -464,12 +464,6 @@ sql_column_bytes(sql_stmt * pStmt, int i)
 	return sql_value_bytes(columnMem(pStmt, i));
 }
 
-double
-sql_column_double(sql_stmt * pStmt, int i)
-{
-	return sql_value_double(columnMem(pStmt, i));
-}
-
 bool
 sql_column_boolean(struct sql_stmt *stmt, int i)
 {