Files
doris/be/src/exprs/hll_hash_function.cpp
chenhao7253886 37b4cafe87 Change variable and namespace name in BE (#268)
Change 'palo' to 'doris'
2018-11-02 10:22:32 +08:00

77 lines
2.7 KiB
C++

// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements. See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership. The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the License for the
// specific language governing permissions and limitations
// under the License.
#include "exprs/hll_hash_function.h"
#include "exprs/expr.h"
#include "runtime/tuple_row.h"
#include "runtime/datetime_value.h"
#include "util/path_builder.h"
#include "runtime/string_value.hpp"
#include "exprs/aggregate_functions.h"
#include "exprs/cast_functions.h"
#include "olap/olap_common.h"
#include "olap/utils.h"
namespace doris {
using doris_udf::BigIntVal;
using doris_udf::StringVal;
const int HllHashFunctions::HLL_INIT_EXPLICT_SET_SIZE = 10;
const int HllHashFunctions::HLL_EMPTY_SET_SIZE = 1;
void HllHashFunctions::init() {
}
StringVal HllHashFunctions::create_string_result(doris_udf::FunctionContext* ctx,
const StringVal& val, const bool is_null) {
StringVal result;
if (is_null) {
// HLL_DATA_EMPTY
char buf[HLL_EMPTY_SET_SIZE];
buf[0] = HLL_DATA_EMPTY;
result = AnyValUtil::from_buffer_temp(ctx, buf, sizeof(buf));
} else {
// HLL_DATA_EXPLHLL_DATA_EXPLICIT
uint64_t hash = HashUtil::murmur_hash64A(val.ptr, val.len, HashUtil::MURMUR_SEED);
char buf[HLL_INIT_EXPLICT_SET_SIZE];
buf[0] = HLL_DATA_EXPLICIT;
buf[1] = 1;
*((uint64_t*)(buf + 2)) = hash;
result = AnyValUtil::from_buffer_temp(ctx, buf, sizeof(buf));
}
return result;
}
StringVal HllHashFunctions::hll_hash(doris_udf::FunctionContext* ctx,
const StringVal& input) {
return create_string_result(ctx, input, input.is_null);
}
StringVal HllHashFunctions::hll_cardinality(doris_udf::FunctionContext* ctx,
const StringVal& input) {
if (input.is_null) {
return StringVal::null();
}
StringVal dst;
AggregateFunctions::hll_union_agg_init(ctx, &dst);
AggregateFunctions::hll_union_agg_update(ctx, input, &dst);
return AggregateFunctions::hll_union_agg_finalize(ctx, dst);
}
}