[Tarantool-patches] [PATCH v1 3/4] sql: introduce cast for decimal
Mergen Imeev
imeevma at tarantool.org
Wed Aug 18 16:29:26 MSK 2021
Thank you for the review! My answer and diff below.
On Mon, Aug 16, 2021 at 10:34:16PM +0300, Safin Timur wrote:
> Oh, now I see the reasonable implicit and explicit casts table for decimals.
> I disavow my prior complain about missing directions for CAST(exprt AS
> DECIMAL).
>
> Below there is minor complain though...
>
> On 16.08.2021 18:57, Mergen Imeev via Tarantool-patches wrote:
> > This patch introduces implicit and explicit cast of the DECIMAL field in
> > SQL. Implicit cast to and from DECIMAL is precise. Explicit conversion
> > to decimal and back could lead to loss of precision.
> >
> > Part of #4415
> > ---
> > src/box/sql/mem.c | 334 ++++++++++++++++++++++++++++++-
> > test/sql-tap/decimal.test.lua | 366 +++++++++++++++++++++++++++++++++-
> > 2 files changed, 695 insertions(+), 5 deletions(-)
> >
> > diff --git a/src/box/sql/mem.c b/src/box/sql/mem.c
> > index 016f0e80b..ff8b40d7f 100644
> > --- a/src/box/sql/mem.c
> > +++ b/src/box/sql/mem.c
> > @@ -678,6 +678,17 @@ int_to_double_forced(struct Mem *mem)
> > return CMP_OLD_NEW(i, d, int64_t);
> > }
> > +static inline int
> > +int_to_dec(struct Mem *mem)
> > +{
> > + assert(mem->type == MEM_TYPE_INT);
> > + int64_t i = mem->u.i;
> > + decimal_from_int64(&mem->u.d, i);
> > + mem->type = MEM_TYPE_DEC;
> > + mem->flags = 0;
> > + return 0;
> > +}
> > +
> > static inline int
> > uint_to_double_precise(struct Mem *mem)
> > {
> > @@ -709,6 +720,17 @@ uint_to_double_forced(struct Mem *mem)
> > return CMP_OLD_NEW(u, d, uint64_t);
> > }
> > +static inline int
> > +uint_to_dec(struct Mem *mem)
> > +{
> > + assert(mem->type == MEM_TYPE_UINT);
> > + int64_t u = mem->u.u;
> > + decimal_from_uint64(&mem->u.d, u);
> > + mem->type = MEM_TYPE_DEC;
> > + mem->flags = 0;
> > + return 0;
> > +}
> > +
> > static inline int
> > int_to_str0(struct Mem *mem)
> > {
> > @@ -855,6 +877,19 @@ str_to_double(struct Mem *mem)
> > return 0;
> > }
> > +static inline int
> > +str_to_dec(struct Mem *mem)
> > +{
> > + assert(mem->type == MEM_TYPE_STR);
> > + decimal_t dec;
> > + decimal_t *d;
> > + d = decimal_from_string(&dec, mem->z);
> > + if (d == NULL)
> > + return -1;
> > + mem_set_dec(mem, &dec);
> > + return 0;
> > +}
> > +
> > static inline int
> > double_to_int(struct Mem *mem)
> > {
> > @@ -988,6 +1023,69 @@ double_to_uint_forced(struct Mem *mem)
> > return res;
> > }
> > +static inline int
> > +double_to_dec(struct Mem *mem)
> > +{
> > + assert(mem->type == MEM_TYPE_DOUBLE);
> > + double d = mem->u.r;
> > + if (d >= 1e38 || d <= -1e38)
> > + return -1;
> > + decimal_from_double(&mem->u.d, d);
> > + mem->type = MEM_TYPE_DEC;
> > + mem->flags = 0;
> > + return 0;
> > +}
> > +
> > +static inline int
> > +double_to_dec_precise(struct Mem *mem)
> > +{
> > + assert(mem->type == MEM_TYPE_DOUBLE);
> > + double d = mem->u.r;
> > + if (d >= 1e38 || d <= -1e38)
> > + return -1;
> > + decimal_t dec;
> > + decimal_from_double(&dec, d);
> > + if (atof(decimal_str(&mem->u.d)) != d)
> > + return -1;
> > + mem->u.d = dec;
> > + mem->type = MEM_TYPE_DEC;
> > + mem->flags = 0;
> > + return 0;
> > +}
> > +
> > +/**
> > + * Cast MEM with DOUBLE to DECIMAL. Doesn't fail. The return value is < 0
> > if
> > + * the original value is less than the result, > 0 if the original value
> > is
> > + * greater than the result, and 0 if the cast is precise.
> > + */
> > +static inline int
> > +double_to_dec_forced(struct Mem *mem)
> > +{
> > + assert(mem->type == MEM_TYPE_DOUBLE);
> > + double d = mem->u.r;
> > + mem->type = MEM_TYPE_DEC;
> > + mem->flags = 0;
> > + if (d >= 1e38) {
> > + const char *val =
> > "99999999999999999999999999999999999999";
> > + assert(strlen(val) == 38);
> > + decimal_from_string(&mem->u.d, val);
> > + return 1;
> > + }
> > + if (d <= -1e38) {
> > + const char *val =
> > "-99999999999999999999999999999999999999";
> > + assert(strlen(val) == 39);
> > + decimal_from_string(&mem->u.d, val);
> > + return -1;
> > + }
> > + decimal_from_double(&mem->u.d, d);
> > + double tmp = atof(decimal_str(&mem->u.d));
> > + if (d > tmp)
> > + return 1;
> > + if (d < tmp)
> > + return -1;
> > + return 0;
> > +}
> > +
> > static inline int
> > double_to_str0(struct Mem *mem)
> > {
> > @@ -1001,6 +1099,173 @@ double_to_str0(struct Mem *mem)
> > return 0;
> > }
> > +static inline int
> > +dec_to_int(struct Mem *mem)
> > +{
> > + assert(mem->type == MEM_TYPE_DEC);
> > + if (decimal_is_neg(&mem->u.d)) {
> > + int64_t i;
> > + if (decimal_to_int64(&mem->u.d, &i) == NULL)
> > + return -1;
> > + assert(i < 0);
> > + mem->u.i = i;
> > + mem->type = MEM_TYPE_INT;
> > + mem->flags = 0;
> > + return 0;
> > + }
> > + uint64_t u;
> > + if (decimal_to_uint64(&mem->u.d, &u) == NULL)
> > + return -1;
> > + mem->u.u = u;
> > + mem->type = MEM_TYPE_UINT;
> > + mem->flags = 0;
> > + return 0;
> > +}
> > +
> > +static inline int
> > +dec_to_int_precise(struct Mem *mem)
> > +{
> > + assert(mem->type == MEM_TYPE_DEC);
> > + if (!decimal_is_int(&mem->u.d))
> > + return -1;
> > + return dec_to_int(mem);
> > +}
> > +
> > +static inline int
> > +dec_to_int_forced(struct Mem *mem)
> > +{
> > + assert(mem->type == MEM_TYPE_DEC);
> > + if (decimal_is_neg(&mem->u.d)) {
> > + int64_t i;
> > + mem->type = MEM_TYPE_INT;
> > + mem->flags = 0;
> > + if (decimal_to_int64(&mem->u.d, &i) == NULL) {
> > + mem->u.i = INT64_MIN;
> > + return -1;
> > + }
> > + assert(i < 0);
> > + mem->u.i = i;
> > + /*
> > + * Decimal is floored when cast to int, which means that
> > after
> > + * cast it becomes bigger if it was not integer.
> > + */
> > + return decimal_is_int(&mem->u.d) ? 0 : -1;
> > + }
> > + uint64_t u;
> > + mem->type = MEM_TYPE_UINT;
> > + mem->flags = 0;
> > + if (decimal_to_uint64(&mem->u.d, &u) == NULL) {
> > + mem->u.u = UINT64_MAX;
> > + return 1;
> > + }
> > + mem->u.u = u;
> > + /*
> > + * Decimal is floored when cast to uint, which means that after
> > cast it
> > + * becomes less if it was not integer.
> > + */
> > + return decimal_is_int(&mem->u.d) ? 0 : 1;
> > +}
> > +
> > +static inline int
> > +dec_to_uint(struct Mem *mem)
> > +{
> > + assert(mem->type == MEM_TYPE_DEC);
> > + uint64_t u;
> > + if (decimal_to_uint64(&mem->u.d, &u) == NULL)
> > + return -1;
> > + mem->u.u = u;
> > + mem->type = MEM_TYPE_UINT;
> > + mem->flags = 0;
> > + return 0;
> > +}
> > +
> > +static inline int
> > +dec_to_uint_precise(struct Mem *mem)
> > +{
> > + assert(mem->type == MEM_TYPE_DEC);
> > + if (!decimal_is_int(&mem->u.d))
> > + return -1;
> > + return dec_to_uint(mem);
> > +}
> > +
> > +static inline int
> > +dec_to_uint_forced(struct Mem *mem)
> > +{
> > + assert(mem->type == MEM_TYPE_DEC);
> > + uint64_t u;
> > + mem->type = MEM_TYPE_UINT;
> > + mem->flags = 0;
> > + if (decimal_to_uint64(&mem->u.d, &u) == NULL) {
> > + if (decimal_is_neg(&mem->u.d)) {
> > + mem->u.u = 0;
> > + return -1;
> > + }
> > + mem->u.u = UINT64_MAX;
> > + return 1;
> > + }
> > + mem->u.u = u;
> > + /*
> > + * Decimal is floored when cast to uint, which means that after
> > cast if
> > + * if was not integer it becomes less if it was positive, and move
> > if it
> > + * was negative.
> > + */
> > + if (decimal_is_int(&mem->u.d))
> > + return 0;
> > + return decimal_is_neg(&mem->u.d) ? -1 : 1;
> > +}
> > +
> > +static inline int
> > +dec_to_double(struct Mem *mem)
> > +{
> > + assert(mem->type == MEM_TYPE_DEC);
> > + double r = atof(decimal_str(&mem->u.d));
> > + mem->u.r = r;
> > + mem->type = MEM_TYPE_DOUBLE;
> > + mem->flags = 0;
> > + return 0;
> > +}
> > +
> > +static inline int
> > +dec_to_double_precise(struct Mem *mem)
> > +{
> > + assert(mem->type == MEM_TYPE_DEC);
> > + double r = atof(decimal_str(&mem->u.d));
> > + decimal_t d;
> > + decimal_t *dec = decimal_from_double(&d, r);
> > + if (dec == NULL || decimal_compare(dec, &mem->u.d) != 0)
> > + return -1;
> > + mem->u.r = r;
> > + mem->type = MEM_TYPE_DOUBLE;
> > + mem->flags = 0;
> > + return 0;
> > +}
> > +
> > +static inline int
> > +dec_to_double_forced(struct Mem *mem)
> > +{
> > + assert(mem->type == MEM_TYPE_DEC);
> > + mem->type = MEM_TYPE_DOUBLE;
> > + mem->flags = 0;
> > + double r = atof(decimal_str(&mem->u.d));
> > + int res;
> > + decimal_t d;
> > + if (r <= -1e38)
> > + res = 1;
> > + else if (r >= 1e38)
> > + res = -1;
> > + else
> > + res = decimal_compare(&mem->u.d, decimal_from_double(&d,
> > r));
> > + mem->u.r = r;
> > + return res;
> > +}
> > +
> > +static inline int
> > +dec_to_str0(struct Mem *mem)
> > +{
> > + assert(mem->type == MEM_TYPE_DEC);
> > + return mem_copy_str0(mem, decimal_str(&mem->u.d));
> > +}
> > +
> > static inline int
> > bool_to_str0(struct Mem *mem)
> > {
> > @@ -1053,6 +1318,8 @@ mem_to_int(struct Mem *mem)
> > return str_to_int(mem);
> > if (mem->type == MEM_TYPE_DOUBLE)
> > return double_to_int(mem);
> > + if (mem->type == MEM_TYPE_DEC)
> > + return dec_to_int(mem);
> > return -1;
> > }
> > @@ -1068,6 +1335,8 @@ mem_to_int_precise(struct Mem *mem)
> > return str_to_int(mem);
> > if (mem->type == MEM_TYPE_DOUBLE)
> > return double_to_int_precise(mem);
> > + if (mem->type == MEM_TYPE_DEC)
> > + return dec_to_int(mem);
> > return -1;
> > }
> > @@ -1083,6 +1352,8 @@ mem_to_double(struct Mem *mem)
> > return int_to_double(mem);
> > if (mem->type == MEM_TYPE_STR)
> > return str_to_double(mem);
> > + if (mem->type == MEM_TYPE_DEC)
> > + return dec_to_double(mem);
> > return -1;
> > }
> > @@ -1129,6 +1400,8 @@ mem_to_str0(struct Mem *mem)
> > return array_to_str0(mem);
> > case MEM_TYPE_UUID:
> > return uuid_to_str0(mem);
> > + case MEM_TYPE_DEC:
> > + return dec_to_str0(mem);
> > default:
> > return -1;
> > }
> > @@ -1157,6 +1430,8 @@ mem_to_str(struct Mem *mem)
> > return array_to_str0(mem);
> > case MEM_TYPE_UUID:
> > return uuid_to_str0(mem);
> > + case MEM_TYPE_DEC:
> > + return dec_to_str0(mem);
> > default:
> > return -1;
> > }
> > @@ -1177,6 +1452,8 @@ mem_cast_explicit(struct Mem *mem, enum field_type
> > type)
> > return str_to_uint(mem);
> > case MEM_TYPE_DOUBLE:
> > return double_to_uint(mem);
> > + case MEM_TYPE_DEC:
> > + return dec_to_uint(mem);
> > default:
> > return -1;
> > }
> > @@ -1209,9 +1486,21 @@ mem_cast_explicit(struct Mem *mem, enum field_type
> > type)
> > case FIELD_TYPE_NUMBER:
> > return mem_to_number(mem);
> > case FIELD_TYPE_DECIMAL:
> > - if (mem->type == MEM_TYPE_DEC)
> > + switch (mem->type) {
> > + case MEM_TYPE_INT:
> > + return int_to_dec(mem);
> > + case MEM_TYPE_UINT:
> > + return uint_to_dec(mem);
> > + case MEM_TYPE_STR:
> > + return str_to_dec(mem);
> > + case MEM_TYPE_DOUBLE:
> > + return double_to_dec(mem);
> > + case MEM_TYPE_DEC:
> > + mem->flags = 0;
> > return 0;
> > - return -1;
> > + default:
> > + return -1;
> > + }
>
> For consistency with majority of other numeric directions (mem_to_int(),
> mem_to_number(), mem_to_double()) I'd extract this code similarly to
> mem_to_decimal(). But this is up to you...
>
>
I will do this later, when I have time for some refactoring.
> > case FIELD_TYPE_UUID:
> > if (mem->type == MEM_TYPE_UUID) {
> > mem->flags = 0;
> ...
>
> > @@ -1296,9 +1591,19 @@ mem_cast_implicit(struct Mem *mem, enum field_type
> > type)
> > mem->flags = MEM_Number;
> > return 0;
> > case FIELD_TYPE_DECIMAL:
> > - if (mem->type == MEM_TYPE_DEC)
> > + switch (mem->type) {
> > + case MEM_TYPE_INT:
> > + return int_to_dec(mem);
> > + case MEM_TYPE_UINT:
> > + return uint_to_dec(mem);
> > + case MEM_TYPE_DOUBLE:
> > + return double_to_dec_precise(mem);
> > + case MEM_TYPE_DEC:
> > + mem->flags = 0;
> > return 0;
> > - return -1;
> > + default:
> > + return -1;
> > + }
> > case FIELD_TYPE_MAP:
> > if (mem->type == MEM_TYPE_MAP)
> > return 0;
> > @@ -1343,6 +1648,8 @@ mem_cast_implicit_number(struct Mem *mem, enum
> > field_type type)
> > return -1;
> > case MEM_TYPE_DOUBLE:
> > return double_to_uint_forced(mem);
> > + case MEM_TYPE_DEC:
> > + return dec_to_uint_forced(mem);
> > default:
> > unreachable();
> > }
> > @@ -1353,6 +1660,8 @@ mem_cast_implicit_number(struct Mem *mem, enum
> > field_type type)
> > return int_to_double_forced(mem);
> > case MEM_TYPE_UINT:
> > return uint_to_double_forced(mem);
> > + case MEM_TYPE_DEC:
> > + return dec_to_double_forced(mem);
> > case MEM_TYPE_DOUBLE:
> > mem->flags = 0;
> > return 0;
> > @@ -1368,6 +1677,23 @@ mem_cast_implicit_number(struct Mem *mem, enum
> > field_type type)
> > return 0;
> > case MEM_TYPE_DOUBLE:
> > return double_to_int_forced(mem);
> > + case MEM_TYPE_DEC:
> > + return dec_to_int_forced(mem);
> > + default:
> > + unreachable();
> > + }
> > + break;
> > + case FIELD_TYPE_DECIMAL:
> > + switch (mem->type) {
> > + case MEM_TYPE_INT:
> > + return int_to_dec(mem);
> > + case MEM_TYPE_UINT:
> > + return uint_to_dec(mem);
> > + case MEM_TYPE_DEC:
> > + mem->flags = 0;
> > + return 0;
> > + case MEM_TYPE_DOUBLE:
> > + return double_to_dec_forced(mem);
> > default:
> > unreachable();
> > }
>
> Otherwise great patch, with the expected extension to explicit/implicit
> casts tables.
>
> Thanks,
> Timur
Diff:
diff --git a/src/box/sql/mem.c b/src/box/sql/mem.c
index ff8b40d7f..92f671ab5 100644
--- a/src/box/sql/mem.c
+++ b/src/box/sql/mem.c
@@ -1028,9 +1028,10 @@ double_to_dec(struct Mem *mem)
{
assert(mem->type == MEM_TYPE_DOUBLE);
double d = mem->u.r;
- if (d >= 1e38 || d <= -1e38)
+ decimal_t dec;
+ if (decimal_from_double(&dec, d) == NULL)
return -1;
- decimal_from_double(&mem->u.d, d);
+ mem->u.d = dec;
mem->type = MEM_TYPE_DEC;
mem->flags = 0;
return 0;
@@ -1041,11 +1042,9 @@ double_to_dec_precise(struct Mem *mem)
{
assert(mem->type == MEM_TYPE_DOUBLE);
double d = mem->u.r;
- if (d >= 1e38 || d <= -1e38)
- return -1;
decimal_t dec;
- decimal_from_double(&dec, d);
- if (atof(decimal_str(&mem->u.d)) != d)
+ if (decimal_from_double(&dec, d) == NULL ||
+ atof(decimal_str(&dec)) != d)
return -1;
mem->u.d = dec;
mem->type = MEM_TYPE_DEC;
@@ -1206,8 +1205,9 @@ dec_to_uint_forced(struct Mem *mem)
mem->u.u = u;
/*
* Decimal is floored when cast to uint, which means that after cast if
- * if was not integer it becomes less if it was positive, and move if it
- * was negative.
+ * it was not integer it becomes less if it was positive, and move if it
+ * was negative. For example, DECIMAL value -1.5 becomes -1 after cast
+ * to INTEGER and DECIMAL value 1.5 becomes 1 after cast to INTEGER.
*/
if (decimal_is_int(&mem->u.d))
return 0;
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