[Tarantool-patches] [PATCH v2 2/2] Add IsInt method for checking the fractional part of a number
Chris Sosnin
k.sosnin at tarantool.org
Thu Jun 25 17:22:48 MSK 2020
Thank you for the review!
> On 25 Jun 2020, at 01:23, Vladislav Shpilevoy <v.shpilevoy at tarantool.org> wrote:
>
> Thanks for the patch!
>
> Technically looks fine. But see two style comments below.
>
> On 24/06/2020 18:53, Chris Sosnin wrote:
>> Currently there is no efficient way to do this.
>>
>> Needed for tarantool/tarantool#4415
>> ---
>> decNumber.c | 27 +++++++++++++++++++++++++++
>> decNumber.h | 1 +
>> 2 files changed, 28 insertions(+)
>>
>> diff --git a/decNumber.c b/decNumber.c
>> index e248656..26acec3 100644
>> --- a/decNumber.c
>> +++ b/decNumber.c
>> @@ -501,6 +501,33 @@ uLong decNumberToUInt64(const decNumber *dn, decContext *set) {
>> return 0;
>> } // decNumberToUInt64
>>
>> +Flag decNumberIsInt(const decNumber *dn) {
>
> 1. It seems Flag type is internal. For public API flags the lib uses int32_t.
> For example, look at decNumberIsNormal(), decNumberIsSubnormal().
I agree, Flag is only used inside decNumber.c, I looked at the wrong function.
Fixed.
>
>> + const Unit *up=dn->lsu;
>> + if (dn->exponent>=0) {
>> + return 1;
>> + }
>> + else {
>> + Int count=-dn->exponent;
>> + // spin up whole units until reach the Unit with the unit digit
>> + for (; count>=DECDPUN; up++) {
>> + if (*up!=0) return 0;
>> + count-=DECDPUN;
>> + }
>> + if (count==0) return 1; // [a multiple of DECDPUN]
>> + else { // [not multiple of DECDPUN]
>> + Int rem; // work
>> + // slice off fraction digits and check for non-zero
>> + #if DECDPUN<=4
>> + rem=*up-QUOT10(*up, count)*powers[count];
>> + #else
>> + rem=*up%powers[count]; // slice off discards
>> + #endif
>> + if (rem!=0) return 0;
>> + }
>> + }
>> + return 1;
>> + } // decNumberIsInt
>> +
>> /* ------------------------------------------------------------------ */
>> /* to-scientific-string -- conversion to numeric string */
>> /* to-engineering-string -- conversion to numeric string */
>> diff --git a/decNumber.h b/decNumber.h
>> index ffaa3d8..9d3a7e1 100644
>> --- a/decNumber.h
>> +++ b/decNumber.h
>> @@ -169,6 +169,7 @@
>> decNumber * decNumberTrim(decNumber *);
>> const char * decNumberVersion(void);
>> decNumber * decNumberZero(decNumber *);
>> + uint8_t decNumberIsInt(const decNumber *dn);
>
> 2. Better move this to the other Is functions a few lines below. Where
> the comment says "Functions for testing decNumbers".
Fixed.
>
>>
>> /* Functions for testing decNumbers (normality depends on context) */
>> int32_t decNumberIsNormal(const decNumber *, decContext *);
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