From: Kari Hurtta <hurtta-ietf@elmme-mailer.org>

Date: Thu, 30 Jan 2020 07:52:29 +0200 (EET)

To: Mark Nottingham <mnot@mnot.net>

CC: Kari Hurtta <hurtta-ietf@elmme-mailer.org>, HTTP Working Group <ietf-http-wg@w3.org>, Poul-Henning Kamp <phk@varnish-cache.org>

Message-Id: <20200130055238.1CFF91F35@welho-filter3.welho.com>

Date: Thu, 30 Jan 2020 07:52:29 +0200 (EET)

To: Mark Nottingham <mnot@mnot.net>

CC: Kari Hurtta <hurtta-ietf@elmme-mailer.org>, HTTP Working Group <ietf-http-wg@w3.org>, Poul-Henning Kamp <phk@varnish-cache.org>

Message-Id: <20200130055238.1CFF91F35@welho-filter3.welho.com>

> Hi Kari, > > Very good catch; I noticed this a while back but forgot to file an issue. Now: > https://github.com/httpwg/http-extensions/issues/1043 | ... still isn't right, as Kari noticed. E.g., a value of 1.9944 won't get rounded to 2.0. You mean: E.g., a value of 1.9998 won't get rounded to 2.0. Algorithm produces three digits for fractional component. And 1.994 is correct rounding for 1.9944, I think. > Cheers, > Another thing what can be issue when rounding is applied. > > On 30 Jan 2020, at 5:17 am, Kari Hurtta <hurtta-ietf@elmme-mailer.org> wrote: > > > > 4.1.5. Serializing a Decimal > > https://tools.ietf.org/html/draft-ietf-httpbis-header-structure-15#section-4.1.5 > > > > > > | Given a decimal_number as input_decimal, return an ASCII string > > | suitable for use in a HTTP header value. > > | > > | 1. Let output be an empty string. > > | > > | 2. If input_decimal is less than (but not equal to) 0, append "-" to > > | output. > > | > > | 3. Append input_decimal's integer component represented in base 10 > > | (using only decimal digits) to output; if it is zero, append "0". > > | > > | 4. If the number of characters appended in the previous step is > > | greater than 12, fail serialisation. A decimal_number number can be -999 999 999 999.9997 or 999 999 999 999.9997 In step 3 there is digits 999999999999 so no failure on step 4 > > | 5. Append "." to output. > > | > > | 6. If input_decimal's fractional component is zero, append "0" to > > | output. > > | > > | 7. Else if input_decimal's fractional component has up to three > > | digits, append them represented in base 10 (using only decimal > > | digits) to output. > > | > > | 8. Otherwise, append the first three digits of input_decimal's > > | fractional component (represented in base 10, using only decimal > > | digits) to output, rounding the final digit to the nearest value, > > | or to the even value if it is equidistant. > > | > > | 9. Return output. First theree digits for fractional component are 999 "Correct" rounding for -999 999 999 999.9997 is -1 000 000 000 000.0 and for 999 999 999 999.9997 is 1 000 000 000 000.0, but there are 13 digits on integer component. That is "solved" if when decimal_number < -999 999 999 999.999 or decimal_number > 999 999 999 999.999, fractional component is truncated to 3 digits and rounding is not tried. / Kari HurttaReceived on Thursday, 30 January 2020 05:52:43 UTC

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