diff options
Diffstat (limited to 'src/backend/utils/adt/arrayfuncs.c')
| -rw-r--r-- | src/backend/utils/adt/arrayfuncs.c | 228 |
1 files changed, 227 insertions, 1 deletions
diff --git a/src/backend/utils/adt/arrayfuncs.c b/src/backend/utils/adt/arrayfuncs.c index 58dfb0fc085..8b0c11c163d 100644 --- a/src/backend/utils/adt/arrayfuncs.c +++ b/src/backend/utils/adt/arrayfuncs.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/utils/adt/arrayfuncs.c,v 1.130 2006/07/14 14:52:23 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/utils/adt/arrayfuncs.c,v 1.131 2006/09/10 20:14:20 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -3345,6 +3345,232 @@ array_cmp(FunctionCallInfo fcinfo) } +/*----------------------------------------------------------------------------- + * array overlap/containment comparisons + * These use the same methods of comparing array elements as array_eq. + * We consider only the elements of the arrays, ignoring dimensionality. + *---------------------------------------------------------------------------- + */ + +/* + * array_contain_compare : + * compares two arrays for overlap/containment + * + * When matchall is true, return true if all members of array1 are in array2. + * When matchall is false, return true if any members of array1 are in array2. + */ +static bool +array_contain_compare(ArrayType *array1, ArrayType *array2, bool matchall, + void **fn_extra) +{ + bool result = matchall; + Oid element_type = ARR_ELEMTYPE(array1); + TypeCacheEntry *typentry; + int nelems1; + Datum *values2; + bool *nulls2; + int nelems2; + int typlen; + bool typbyval; + char typalign; + char *ptr1; + bits8 *bitmap1; + int bitmask; + int i; + int j; + FunctionCallInfoData locfcinfo; + + if (element_type != ARR_ELEMTYPE(array2)) + ereport(ERROR, + (errcode(ERRCODE_DATATYPE_MISMATCH), + errmsg("cannot compare arrays of different element types"))); + + /* + * We arrange to look up the equality function only once per series of + * calls, assuming the element type doesn't change underneath us. The + * typcache is used so that we have no memory leakage when being used + * as an index support function. + */ + typentry = (TypeCacheEntry *) *fn_extra; + if (typentry == NULL || + typentry->type_id != element_type) + { + typentry = lookup_type_cache(element_type, + TYPECACHE_EQ_OPR_FINFO); + if (!OidIsValid(typentry->eq_opr_finfo.fn_oid)) + ereport(ERROR, + (errcode(ERRCODE_UNDEFINED_FUNCTION), + errmsg("could not identify an equality operator for type %s", + format_type_be(element_type)))); + *fn_extra = (void *) typentry; + } + typlen = typentry->typlen; + typbyval = typentry->typbyval; + typalign = typentry->typalign; + + /* + * Since we probably will need to scan array2 multiple times, it's + * worthwhile to use deconstruct_array on it. We scan array1 the hard way + * however, since we very likely won't need to look at all of it. + */ + deconstruct_array(array2, element_type, typlen, typbyval, typalign, + &values2, &nulls2, &nelems2); + + /* + * Apply the comparison operator to each pair of array elements. + */ + InitFunctionCallInfoData(locfcinfo, &typentry->eq_opr_finfo, 2, + NULL, NULL); + + /* Loop over source data */ + nelems1 = ArrayGetNItems(ARR_NDIM(array1), ARR_DIMS(array1)); + ptr1 = ARR_DATA_PTR(array1); + bitmap1 = ARR_NULLBITMAP(array1); + bitmask = 1; + + for (i = 0; i < nelems1; i++) + { + Datum elt1; + bool isnull1; + + /* Get element, checking for NULL */ + if (bitmap1 && (*bitmap1 & bitmask) == 0) + { + isnull1 = true; + elt1 = (Datum) 0; + } + else + { + isnull1 = false; + elt1 = fetch_att(ptr1, typbyval, typlen); + ptr1 = att_addlength(ptr1, typlen, PointerGetDatum(ptr1)); + ptr1 = (char *) att_align(ptr1, typalign); + } + + /* advance bitmap pointer if any */ + bitmask <<= 1; + if (bitmask == 0x100) + { + if (bitmap1) + bitmap1++; + bitmask = 1; + } + + /* + * We assume that the comparison operator is strict, so a NULL + * can't match anything. XXX this diverges from the "NULL=NULL" + * behavior of array_eq, should we act like that? + */ + if (isnull1) + { + if (matchall) + { + result = false; + break; + } + continue; + } + + for (j = 0; j < nelems2; j++) + { + Datum elt2 = values2[j]; + bool isnull2 = nulls2[j]; + bool oprresult; + + if (isnull2) + continue; /* can't match */ + + /* + * Apply the operator to the element pair + */ + locfcinfo.arg[0] = elt1; + locfcinfo.arg[1] = elt2; + locfcinfo.argnull[0] = false; + locfcinfo.argnull[1] = false; + locfcinfo.isnull = false; + oprresult = DatumGetBool(FunctionCallInvoke(&locfcinfo)); + if (oprresult) + break; + } + + if (j < nelems2) + { + /* found a match for elt1 */ + if (!matchall) + { + result = true; + break; + } + } + else + { + /* no match for elt1 */ + if (matchall) + { + result = false; + break; + } + } + } + + pfree(values2); + pfree(nulls2); + + return result; +} + +Datum +arrayoverlap(PG_FUNCTION_ARGS) +{ + ArrayType *array1 = PG_GETARG_ARRAYTYPE_P(0); + ArrayType *array2 = PG_GETARG_ARRAYTYPE_P(1); + bool result; + + result = array_contain_compare(array1, array2, false, + &fcinfo->flinfo->fn_extra); + + /* Avoid leaking memory when handed toasted input. */ + PG_FREE_IF_COPY(array1, 0); + PG_FREE_IF_COPY(array2, 1); + + PG_RETURN_BOOL(result); +} + +Datum +arraycontains(PG_FUNCTION_ARGS) +{ + ArrayType *array1 = PG_GETARG_ARRAYTYPE_P(0); + ArrayType *array2 = PG_GETARG_ARRAYTYPE_P(1); + bool result; + + result = array_contain_compare(array2, array1, true, + &fcinfo->flinfo->fn_extra); + + /* Avoid leaking memory when handed toasted input. */ + PG_FREE_IF_COPY(array1, 0); + PG_FREE_IF_COPY(array2, 1); + + PG_RETURN_BOOL(result); +} + +Datum +arraycontained(PG_FUNCTION_ARGS) +{ + ArrayType *array1 = PG_GETARG_ARRAYTYPE_P(0); + ArrayType *array2 = PG_GETARG_ARRAYTYPE_P(1); + bool result; + + result = array_contain_compare(array1, array2, true, + &fcinfo->flinfo->fn_extra); + + /* Avoid leaking memory when handed toasted input. */ + PG_FREE_IF_COPY(array1, 0); + PG_FREE_IF_COPY(array2, 1); + + PG_RETURN_BOOL(result); +} + + /***************************************************************************/ /******************| Support Routines |*****************/ /***************************************************************************/ |