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Fix longstanding error in contrib/intarray's int[] & int[] operator.

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The array intersection code would give wrong results if the first entry of
the correct output array would be "1".  (I think only this value could be
at risk, since the previous word would always be a lower-bound entry with
that fixed value.)

Problem spotted by Julien Rouhaud, initial patch by Guillaume Lelarge,
cosmetic improvements by me.
This commit is contained in:
Tom Lane 2012-02-16 20:00:11 -05:00
parent 4767bc8ff2
commit 06d9afa6f9
3 changed files with 14 additions and 6 deletions
contrib/intarray
_int_tool.c
expected
_int.out
sql
_int.sql

13
contrib/intarray/_int_tool.c

@ -140,7 +140,8 @@ inner_int_inter(ArrayType *a, ArrayType *b)
*db,
*dr;
int i,
j;
j,
k;
if (ARRISEMPTY(a) || ARRISEMPTY(b))
return new_intArrayType(0);
@ -152,15 +153,15 @@ inner_int_inter(ArrayType *a, ArrayType *b)
r = new_intArrayType(Min(na, nb));
dr = ARRPTR(r);
i = j = 0;
i = j = k = 0;
while (i < na && j < nb)
{
if (da[i] < db[j])
i++;
else if (da[i] == db[j])
{
if (i + j == 0 || (i + j > 0 && *(dr - 1) != db[j]))
*dr++ = db[j];
if (k == 0 || dr[k - 1] != db[j])
dr[k++] = db[j];
i++;
j++;
}
@ -168,13 +169,13 @@ inner_int_inter(ArrayType *a, ArrayType *b)
j++;
}
if ((dr - ARRPTR(r)) == 0)
if (k == 0)
{
pfree(r);
return new_intArrayType(0);
}
else
return resize_intArrayType(r, dr - ARRPTR(r));
return resize_intArrayType(r, k);
}
void

6
contrib/intarray/expected/_int.out

@ -137,6 +137,12 @@ SELECT '{123,623,445}'::int[] & '{1623,623}';
{623}
(1 row)
SELECT '{-1,3,1}'::int[] & '{1,2}';
?column?
----------
{1}
(1 row)
--test query_int
SELECT '1'::query_int;
query_int

1
contrib/intarray/sql/_int.sql

@ -24,6 +24,7 @@ SELECT '{123,623,445}'::int[] | 623;
SELECT '{123,623,445}'::int[] | 1623;
SELECT '{123,623,445}'::int[] | '{1623,623}';
SELECT '{123,623,445}'::int[] & '{1623,623}';
SELECT '{-1,3,1}'::int[] & '{1,2}';
--test query_int