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MAINT: port numpy#13188 for np_datetime simplification (#26516)
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* MAINT: port numpy#13188 for np_datetime simplificaion

Bring numpy changes about emulating the behavior of python's divmod to
pandas.

* cpplint fix

* Add reference numpy change into comment

* fix typo
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@xcz011 @jbrockmendel
xcz011 authored and jbrockmendel committed May 26, 2019
1 parent 7e88819 commit 0a516c1
Showing 1 changed file with 81 additions and 127 deletions.
208 changes: 81 additions & 127 deletions pandas/_libs/tslibs/src/datetime/np_datetime.c
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Original file line number Diff line number Diff line change
Expand Up @@ -498,6 +498,27 @@ npy_datetime npy_datetimestruct_to_datetime(NPY_DATETIMEUNIT base,
return ret;
}

/*
* Port numpy#13188 https://github.com/numpy/numpy/pull/13188/
*
* Computes the python `ret, d = divmod(d, unit)`.
*
* Note that GCC is smart enough at -O2 to eliminate the `if(*d < 0)` branch
* for subsequent calls to this command - it is able to deduce that `*d >= 0`.
*/
npy_int64 extract_unit(npy_datetime *d, npy_datetime unit) {
assert(unit > 0);
npy_int64 div = *d / unit;
npy_int64 mod = *d % unit;
if (mod < 0) {
mod += unit;
div -= 1;
}
assert(mod >= 0);
*d = mod;
return div;
}

/*
* Converts a datetime based on the given metadata into a datetimestruct
*/
Expand All @@ -522,13 +543,8 @@ void pandas_datetime_to_datetimestruct(npy_datetime dt,
break;

case NPY_FR_M:
if (dt >= 0) {
out->year = 1970 + dt / 12;
out->month = dt % 12 + 1;
} else {
out->year = 1969 + (dt + 1) / 12;
out->month = 12 + (dt + 1) % 12;
}
out->year = 1970 + extract_unit(&dt, 12);
out->month = dt + 1;
break;

case NPY_FR_W:
Expand All @@ -543,167 +559,105 @@ void pandas_datetime_to_datetimestruct(npy_datetime dt,
case NPY_FR_h:
perday = 24LL;

if (dt >= 0) {
set_datetimestruct_days(dt / perday, out);
dt = dt % perday;
} else {
set_datetimestruct_days(
dt / perday - (dt % perday == 0 ? 0 : 1), out);
dt = (perday - 1) + (dt + 1) % perday;
}
set_datetimestruct_days(extract_unit(&dt, perday), out);
out->hour = dt;
break;

case NPY_FR_m:
perday = 24LL * 60;

if (dt >= 0) {
set_datetimestruct_days(dt / perday, out);
dt = dt % perday;
} else {
set_datetimestruct_days(
dt / perday - (dt % perday == 0 ? 0 : 1), out);
dt = (perday - 1) + (dt + 1) % perday;
}
out->hour = dt / 60;
out->min = dt % 60;
set_datetimestruct_days(extract_unit(&dt, perday), out);
out->hour = (int)extract_unit(&dt, 60);
out->min = (int)dt;
break;

case NPY_FR_s:
perday = 24LL * 60 * 60;

if (dt >= 0) {
set_datetimestruct_days(dt / perday, out);
dt = dt % perday;
} else {
set_datetimestruct_days(
dt / perday - (dt % perday == 0 ? 0 : 1), out);
dt = (perday - 1) + (dt + 1) % perday;
}
out->hour = dt / (60 * 60);
out->min = (dt / 60) % 60;
out->sec = dt % 60;
set_datetimestruct_days(extract_unit(&dt, perday), out);
out->hour = (int)extract_unit(&dt, 60 * 60);
out->min = (int)extract_unit(&dt, 60);
out->sec = (int)dt;
break;

case NPY_FR_ms:
perday = 24LL * 60 * 60 * 1000;

if (dt >= 0) {
set_datetimestruct_days(dt / perday, out);
dt = dt % perday;
} else {
set_datetimestruct_days(
dt / perday - (dt % perday == 0 ? 0 : 1), out);
dt = (perday - 1) + (dt + 1) % perday;
}
out->hour = dt / (60 * 60 * 1000LL);
out->min = (dt / (60 * 1000LL)) % 60;
out->sec = (dt / 1000LL) % 60;
out->us = (dt % 1000LL) * 1000;
set_datetimestruct_days(extract_unit(&dt, perday), out);
out->hour = (int)extract_unit(&dt, 1000LL * 60 * 60);
out->min = (int)extract_unit(&dt, 1000LL * 60);
out->sec = (int)extract_unit(&dt, 1000LL);
out->us = (int)(dt * 1000);
break;

case NPY_FR_us:
perday = 24LL * 60LL * 60LL * 1000LL * 1000LL;

if (dt >= 0) {
set_datetimestruct_days(dt / perday, out);
dt = dt % perday;
} else {
set_datetimestruct_days(
dt / perday - (dt % perday == 0 ? 0 : 1), out);
dt = (perday - 1) + (dt + 1) % perday;
}
out->hour = dt / (60 * 60 * 1000000LL);
out->min = (dt / (60 * 1000000LL)) % 60;
out->sec = (dt / 1000000LL) % 60;
out->us = dt % 1000000LL;
set_datetimestruct_days(extract_unit(&dt, perday), out);
out->hour = (int)extract_unit(&dt, 1000LL * 1000 * 60 * 60);
out->min = (int)extract_unit(&dt, 1000LL * 1000 * 60);
out->sec = (int)extract_unit(&dt, 1000LL * 1000);
out->us = (int)dt;
break;

case NPY_FR_ns:
perday = 24LL * 60LL * 60LL * 1000LL * 1000LL * 1000LL;

if (dt >= 0) {
set_datetimestruct_days(dt / perday, out);
dt = dt % perday;
} else {
set_datetimestruct_days(
dt / perday - (dt % perday == 0 ? 0 : 1), out);
dt = (perday - 1) + (dt + 1) % perday;
}
out->hour = dt / (60 * 60 * 1000000000LL);
out->min = (dt / (60 * 1000000000LL)) % 60;
out->sec = (dt / 1000000000LL) % 60;
out->us = (dt / 1000LL) % 1000000LL;
out->ps = (dt % 1000LL) * 1000;
set_datetimestruct_days(extract_unit(&dt, perday), out);
out->hour = (int)extract_unit(&dt, 1000LL * 1000 * 1000 * 60 * 60);
out->min = (int)extract_unit(&dt, 1000LL * 1000 * 1000 * 60);
out->sec = (int)extract_unit(&dt, 1000LL * 1000 * 1000);
out->us = (int)extract_unit(&dt, 1000LL);
out->ps = (int)(dt * 1000);
break;

case NPY_FR_ps:
perday = 24LL * 60 * 60 * 1000 * 1000 * 1000 * 1000;

if (dt >= 0) {
set_datetimestruct_days(dt / perday, out);
dt = dt % perday;
} else {
set_datetimestruct_days(
dt / perday - (dt % perday == 0 ? 0 : 1), out);
dt = (perday - 1) + (dt + 1) % perday;
}
out->hour = dt / (60 * 60 * 1000000000000LL);
out->min = (dt / (60 * 1000000000000LL)) % 60;
out->sec = (dt / 1000000000000LL) % 60;
out->us = (dt / 1000000LL) % 1000000LL;
out->ps = dt % 1000000LL;
set_datetimestruct_days(extract_unit(&dt, perday), out);
out->hour = (int)extract_unit(&dt, 1000LL * 1000 * 1000 * 60 * 60);
out->min = (int)extract_unit(&dt, 1000LL * 1000 * 1000 * 60);
out->sec = (int)extract_unit(&dt, 1000LL * 1000 * 1000);
out->us = (int)extract_unit(&dt, 1000LL);
out->ps = (int)(dt * 1000);
break;

case NPY_FR_fs:
/* entire range is only +- 2.6 hours */
if (dt >= 0) {
out->hour = dt / (60 * 60 * 1000000000000000LL);
out->min = (dt / (60 * 1000000000000000LL)) % 60;
out->sec = (dt / 1000000000000000LL) % 60;
out->us = (dt / 1000000000LL) % 1000000LL;
out->ps = (dt / 1000LL) % 1000000LL;
out->as = (dt % 1000LL) * 1000;
} else {
npy_datetime minutes;

minutes = dt / (60 * 1000000000000000LL);
dt = dt % (60 * 1000000000000000LL);
if (dt < 0) {
dt += (60 * 1000000000000000LL);
--minutes;
}
/* Offset the negative minutes */
add_minutes_to_datetimestruct(out, minutes);
out->sec = (dt / 1000000000000000LL) % 60;
out->us = (dt / 1000000000LL) % 1000000LL;
out->ps = (dt / 1000LL) % 1000000LL;
out->as = (dt % 1000LL) * 1000;
out->hour = (int)extract_unit(&dt, 1000LL * 1000 * 1000 * 1000 *
1000 * 60 * 60);
if (out->hour < 0) {
out->year = 1969;
out->month = 12;
out->day = 31;
out->hour += 24;
assert(out->hour >= 0);
}
out->min = (int)extract_unit(&dt, 1000LL * 1000 * 1000 * 1000 *
1000 * 60);
out->sec = (int)extract_unit(&dt, 1000LL * 1000 * 1000 * 1000 *
1000);
out->us = (int)extract_unit(&dt, 1000LL * 1000 * 1000);
out->ps = (int)extract_unit(&dt, 1000LL);
out->as = (int)(dt * 1000);
break;

case NPY_FR_as:
/* entire range is only +- 9.2 seconds */
if (dt >= 0) {
out->sec = (dt / 1000000000000000000LL) % 60;
out->us = (dt / 1000000000000LL) % 1000000LL;
out->ps = (dt / 1000000LL) % 1000000LL;
out->as = dt % 1000000LL;
} else {
npy_datetime seconds;

seconds = dt / 1000000000000000000LL;
dt = dt % 1000000000000000000LL;
if (dt < 0) {
dt += 1000000000000000000LL;
--seconds;
}
/* Offset the negative seconds */
add_seconds_to_datetimestruct(out, seconds);
out->us = (dt / 1000000000000LL) % 1000000LL;
out->ps = (dt / 1000000LL) % 1000000LL;
out->as = dt % 1000000LL;
out->sec = (int)extract_unit(&dt, 1000LL * 1000 * 1000 * 1000 *
1000 * 1000);
if (out->sec < 0) {
out->year = 1969;
out->month = 12;
out->day = 31;
out->hour = 23;
out->min = 59;
out->sec += 60;
assert(out->sec >= 0);
}
out->us = (int)extract_unit(&dt, 1000LL * 1000 * 1000 * 1000);
out->ps = (int)extract_unit(&dt, 1000LL * 1000);
out->as = (int)dt;
break;

default:
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