diff options
Diffstat (limited to 'src/backend/utils/adt/varbit.c')
| -rw-r--r-- | src/backend/utils/adt/varbit.c | 26 |
1 files changed, 16 insertions, 10 deletions
diff --git a/src/backend/utils/adt/varbit.c b/src/backend/utils/adt/varbit.c index f0c6a44b842..de3852045b1 100644 --- a/src/backend/utils/adt/varbit.c +++ b/src/backend/utils/adt/varbit.c @@ -1059,7 +1059,7 @@ bitsubstring(VarBit *arg, int32 s, int32 l, bool length_not_specified) len, ishift, i; - int e, + int32 e, s1, e1; bits8 *r, @@ -1072,18 +1072,24 @@ bitsubstring(VarBit *arg, int32 s, int32 l, bool length_not_specified) { e1 = bitlen + 1; } - else + else if (l < 0) + { + /* SQL99 says to throw an error for E < S, i.e., negative length */ + ereport(ERROR, + (errcode(ERRCODE_SUBSTRING_ERROR), + errmsg("negative substring length not allowed"))); + e1 = -1; /* silence stupider compilers */ + } + else if (pg_add_s32_overflow(s, l, &e)) { - e = s + l; - /* - * A negative value for L is the only way for the end position to be - * before the start. SQL99 says to throw an error. + * L could be large enough for S + L to overflow, in which case the + * substring must run to end of string. */ - if (e < s) - ereport(ERROR, - (errcode(ERRCODE_SUBSTRING_ERROR), - errmsg("negative substring length not allowed"))); + e1 = bitlen + 1; + } + else + { e1 = Min(e, bitlen + 1); } if (s1 > bitlen || e1 <= s1) |