diff options
| author | Tom Lane <tgl@sss.pgh.pa.us> | 2009-12-12 19:24:51 +0000 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2009-12-12 19:24:51 +0000 |
| commit | 65a5d12be1651a2c535c8b8f5e99a695d4036159 (patch) | |
| tree | 78997aa5032b1fe3d112e3bdd5f7c7f0e0f561f3 | |
| parent | f25013104a1f5c5a98c59a2fe51b8c3d14772acc (diff) | |
Fix integer-to-bit-string conversions to handle the first fractional byte
correctly when the output bit width is wider than the given integer by
something other than a multiple of 8 bits.
This has been wrong since I first wrote that code for 8.0 :-(. Kudos to
Roman Kononov for being the first to notice, though I didn't use his
patch. Per bug #5237.
| -rw-r--r-- | src/backend/utils/adt/varbit.c | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/src/backend/utils/adt/varbit.c b/src/backend/utils/adt/varbit.c index 23f8d2c9c25..3db46c690f1 100644 --- a/src/backend/utils/adt/varbit.c +++ b/src/backend/utils/adt/varbit.c @@ -9,7 +9,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/utils/adt/varbit.c,v 1.57 2008/01/01 19:45:53 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/utils/adt/varbit.c,v 1.57.2.1 2009/12/12 19:24:51 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -1346,7 +1346,12 @@ bitfromint4(PG_FUNCTION_ARGS) /* store first fractional byte */ if (destbitsleft > srcbitsleft) { - *r++ = (bits8) ((a >> (srcbitsleft - 8)) & BITMASK); + int val = (int) (a >> (destbitsleft - 8)); + + /* Force sign-fill in case the compiler implements >> as zero-fill */ + if (a < 0) + val |= (-1) << (srcbitsleft + 8 - destbitsleft); + *r++ = (bits8) (val & BITMASK); destbitsleft -= 8; } /* Now srcbitsleft and destbitsleft are the same, need not track both */ @@ -1425,7 +1430,12 @@ bitfromint8(PG_FUNCTION_ARGS) /* store first fractional byte */ if (destbitsleft > srcbitsleft) { - *r++ = (bits8) ((a >> (srcbitsleft - 8)) & BITMASK); + int val = (int) (a >> (destbitsleft - 8)); + + /* Force sign-fill in case the compiler implements >> as zero-fill */ + if (a < 0) + val |= (-1) << (srcbitsleft + 8 - destbitsleft); + *r++ = (bits8) (val & BITMASK); destbitsleft -= 8; } /* Now srcbitsleft and destbitsleft are the same, need not track both */ |