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Handle negative values in saturating sub and add
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The functions for saturating addition and subtraction of time values
assumed positive intervals as input. This change generalizes the code
to also handle negative intervals being added or subtracted.
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@erimatnor
erimatnor committed Oct 14, 2020
1 parent 3c801bf commit 9a46609
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Showing 2 changed files with 57 additions and 15 deletions.
38 changes: 26 additions & 12 deletions src/time_utils.c
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Original file line number Diff line number Diff line change
Expand Up @@ -460,19 +460,26 @@ ts_time_get_noend_or_max(Oid timetype)
int64
ts_time_saturating_add(int64 timeval, int64 interval, Oid timetype)
{
int64 min_overflow_result;
int64 max_overflow_result;

if (IS_TIMESTAMP_TYPE(timetype))
{
if (timeval >= (ts_time_get_end(timetype) - interval))
return ts_time_get_noend(timetype);
min_overflow_result = ts_time_get_nobegin(timetype);
max_overflow_result = ts_time_get_noend(timetype);
}
else
{
int64 time_max = ts_time_get_max(timetype);

if (timeval > (time_max - interval))
return time_max;
min_overflow_result = ts_time_get_min(timetype);
max_overflow_result = ts_time_get_max(timetype);
}

if (timeval > 0 && interval > 0 && timeval > (ts_time_get_max(timetype) - interval))
return max_overflow_result;

if (timeval < 0 && interval < 0 && timeval < (ts_time_get_min(timetype) - interval))
return min_overflow_result;

return timeval + interval;
}

Expand All @@ -487,19 +494,26 @@ ts_time_saturating_add(int64 timeval, int64 interval, Oid timetype)
int64
ts_time_saturating_sub(int64 timeval, int64 interval, Oid timetype)
{
int64 min_overflow_result;
int64 max_overflow_result;

if (IS_TIMESTAMP_TYPE(timetype))
{
if (timeval < (ts_time_get_min(timetype) + interval))
return ts_time_get_nobegin(timetype);
min_overflow_result = ts_time_get_nobegin(timetype);
max_overflow_result = ts_time_get_noend(timetype);
}
else
{
int64 time_min = ts_time_get_min(timetype);

if (timeval < (time_min + interval))
return time_min;
min_overflow_result = ts_time_get_min(timetype);
max_overflow_result = ts_time_get_max(timetype);
}

if (timeval < 0 && interval > 0 && timeval < (ts_time_get_min(timetype) + interval))
return min_overflow_result;

if (timeval > 0 && interval < 0 && timeval > (ts_time_get_max(timetype) + interval))
return max_overflow_result;

return timeval - interval;
}

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34 changes: 31 additions & 3 deletions test/src/test_time_utils.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -295,11 +295,11 @@ ts_test_time_utils(PG_FUNCTION_ARGS)
ts_time_get_max(INT8OID));
TestAssertInt64Eq(ts_time_saturating_add(ts_time_get_max(DATEOID), 1, DATEOID),
ts_time_get_noend(DATEOID));
TestAssertInt64Eq(ts_time_saturating_add(ts_time_get_end(DATEOID) - 1, 1, DATEOID),
TestAssertInt64Eq(ts_time_saturating_add(ts_time_get_max(DATEOID), 1, DATEOID),
ts_time_get_noend(DATEOID));
TestAssertInt64Eq(ts_time_saturating_add(ts_time_get_end(TIMESTAMPOID) - 1, 1, TIMESTAMPOID),
TestAssertInt64Eq(ts_time_saturating_add(ts_time_get_max(TIMESTAMPOID), 1, TIMESTAMPOID),
ts_time_get_noend(TIMESTAMPOID));
TestAssertInt64Eq(ts_time_saturating_add(ts_time_get_end(TIMESTAMPTZOID) - 1, 1, TIMESTAMPOID),
TestAssertInt64Eq(ts_time_saturating_add(ts_time_get_max(TIMESTAMPTZOID), 1, TIMESTAMPOID),
ts_time_get_noend(TIMESTAMPOID));
TestAssertInt64Eq(ts_time_saturating_add(ts_time_get_end(DATEOID) - 2, 1, DATEOID),
ts_time_get_max(DATEOID));
Expand All @@ -308,6 +308,21 @@ ts_test_time_utils(PG_FUNCTION_ARGS)
TestAssertInt64Eq(ts_time_saturating_add(ts_time_get_end(TIMESTAMPTZOID) - 2, 1, TIMESTAMPOID),
ts_time_get_max(TIMESTAMPOID));

TestAssertInt64Eq(ts_time_saturating_add(ts_time_get_min(INT2OID), -1, INT2OID),
ts_time_get_min(INT2OID));
TestAssertInt64Eq(ts_time_saturating_add(ts_time_get_min(INT4OID), -1, INT4OID),
ts_time_get_min(INT4OID));
TestAssertInt64Eq(ts_time_saturating_add(ts_time_get_min(INT8OID), -1, INT8OID),
ts_time_get_min(INT8OID));
TestAssertInt64Eq(ts_time_saturating_add(ts_time_get_min(DATEOID), -1, DATEOID),
ts_time_get_nobegin(DATEOID));
TestAssertInt64Eq(ts_time_saturating_add(ts_time_get_min(DATEOID), -1, DATEOID),
ts_time_get_nobegin(DATEOID));
TestAssertInt64Eq(ts_time_saturating_add(ts_time_get_min(TIMESTAMPOID), -1, TIMESTAMPOID),
ts_time_get_nobegin(TIMESTAMPOID));
TestAssertInt64Eq(ts_time_saturating_add(ts_time_get_min(TIMESTAMPTZOID), -1, TIMESTAMPOID),
ts_time_get_nobegin(TIMESTAMPOID));

/* Test saturating subtraction */
TestAssertInt64Eq(ts_time_saturating_sub(ts_time_get_min(INT2OID), 1, INT2OID),
ts_time_get_min(INT2OID));
Expand All @@ -330,5 +345,18 @@ ts_test_time_utils(PG_FUNCTION_ARGS)
TIMESTAMPTZOID),
ts_time_get_min(TIMESTAMPTZOID));

TestAssertInt64Eq(ts_time_saturating_sub(ts_time_get_max(INT2OID), -1, INT2OID),
ts_time_get_max(INT2OID));
TestAssertInt64Eq(ts_time_saturating_sub(ts_time_get_max(INT4OID), -1, INT4OID),
ts_time_get_max(INT4OID));
TestAssertInt64Eq(ts_time_saturating_sub(ts_time_get_max(INT8OID), -1, INT8OID),
ts_time_get_max(INT8OID));
TestAssertInt64Eq(ts_time_saturating_sub(ts_time_get_max(DATEOID), -1, DATEOID),
ts_time_get_noend(DATEOID));
TestAssertInt64Eq(ts_time_saturating_sub(ts_time_get_max(TIMESTAMPOID), -1, TIMESTAMPOID),
ts_time_get_noend(TIMESTAMPOID));
TestAssertInt64Eq(ts_time_saturating_sub(ts_time_get_max(TIMESTAMPTZOID), -1, TIMESTAMPTZOID),
ts_time_get_noend(TIMESTAMPTZOID));

PG_RETURN_VOID();
}

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