// 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 <glog/logging.h>

#include <array>

#include <cctype>

#include <cstddef>

#include <cstring>

#include <functional>

#include <memory>

#include <string>

#include <utility>

#include "common/status.h"

#include "core/assert_cast.h"

#include "core/block/block.h"

#include "core/block/column_numbers.h"

#include "core/block/column_with_type_and_name.h"

#include "core/column/column.h"

#include "core/column/column_nullable.h"

#include "core/column/column_string.h"

#include "core/column/column_vector.h"

#include "core/data_type/data_type.h"

#include "core/data_type/data_type_nullable.h"

#include "core/data_type/data_type_number.h"

#include "core/data_type/data_type_string.h"

#include "core/types.h"

#include "exprs/aggregate/aggregate_function.h"

#include "exprs/function/function.h"

#include "exprs/function/simple_function_factory.h"

#include "util/block_compression.h"

#include "util/faststring.h"

namespace doris {

class FunctionContext;

} // namespace doris

namespace doris {

static constexpr int COMPRESS_STR_LENGTH = 4;

class FunctionCompress : public IFunction {

public:

static constexpr auto name = "compress";

static FunctionPtr create() { return std::make_shared<FunctionCompress>(); }

String get_name() const override { return name; }

size_t get_number_of_arguments() const override { return 1; }

DataTypePtr get_return_type_impl(const DataTypes& arguments) const override {

return std::make_shared<DataTypeString>();

}

Status execute_impl(FunctionContext* context, Block& block, const ColumnNumbers& arguments,

uint32_t result, size_t input_rows_count) const override {

// Get the compression algorithm object

BlockCompressionCodec* compression_codec;

RETURN_IF_ERROR(get_block_compression_codec(segment_v2::CompressionTypePB::ZLIB,

&compression_codec));

const auto& arg_column =

assert_cast<const ColumnString&>(*block.get_by_position(arguments[0]).column);

auto result_column = ColumnString::create();

auto& arg_data = arg_column.get_chars();

auto& arg_offset = arg_column.get_offsets();

const char* arg_begin = reinterpret_cast<const char*>(arg_data.data());

auto& col_data = result_column->get_chars();

auto& col_offset = result_column->get_offsets();

col_offset.resize(input_rows_count);

faststring compressed_str;

Slice data;

// When the original string is large, the result is roughly this value

size_t total = arg_offset[input_rows_count - 1];

col_data.reserve(total / 1000);

for (size_t row = 0; row < input_rows_count; row++) {

uint32_t length = arg_offset[row] - arg_offset[row - 1];

data = Slice(arg_begin + arg_offset[row - 1], length);

size_t idx = col_data.size();

if (!length) { // data is ''

col_offset[row] = col_offset[row - 1];

continue;

}

// Z_MEM_ERROR and Z_BUF_ERROR are already handled in compress, making sure st is always Z_OK

RETURN_IF_ERROR(compression_codec->compress(data, &compressed_str));

col_data.resize(col_data.size() + COMPRESS_STR_LENGTH + compressed_str.size());

std::memcpy(col_data.data() + idx, &length, sizeof(length));

idx += COMPRESS_STR_LENGTH;

// The length of compress_str is not known in advance, so it cannot be compressed directly into col_data

unsigned char* src = compressed_str.data();

for (size_t i = 0; i < compressed_str.size(); idx++, i++, src++) {

col_data[idx] = *src;

}

col_offset[row] =

col_offset[row - 1] + COMPRESS_STR_LENGTH + (int)compressed_str.size();

}

block.replace_by_position(result, std::move(result_column));

return Status::OK();

}

};

class FunctionUncompress : public IFunction {

public:

static constexpr auto name = "uncompress";

static FunctionPtr create() { return std::make_shared<FunctionUncompress>(); }

String get_name() const override { return name; }

size_t get_number_of_arguments() const override { return 1; }

DataTypePtr get_return_type_impl(const DataTypes& arguments) const override {

return make_nullable(std::make_shared<DataTypeString>());

}

Status execute_impl(FunctionContext* context, Block& block, const ColumnNumbers& arguments,

uint32_t result, size_t input_rows_count) const override {

// Get the compression algorithm object

BlockCompressionCodec* compression_codec;

RETURN_IF_ERROR(get_block_compression_codec(segment_v2::CompressionTypePB::ZLIB,

&compression_codec));

const auto& arg_column =

assert_cast<const ColumnString&>(*block.get_by_position(arguments[0]).column);

auto& arg_data = arg_column.get_chars();

auto& arg_offset = arg_column.get_offsets();

const char* arg_begin = reinterpret_cast<const char*>(arg_data.data());

auto result_column = ColumnString::create();

auto& col_data = result_column->get_chars();

auto& col_offset = result_column->get_offsets();

col_offset.resize(input_rows_count);

auto null_column = ColumnUInt8::create(input_rows_count);

auto& null_map = null_column->get_data();

std::string uncompressed;

Slice data;

Slice uncompressed_slice;

size_t total = arg_offset[input_rows_count - 1];

col_data.reserve(total * 1000);

for (size_t row = 0; row < input_rows_count; row++) {

null_map[row] = false;

data = Slice(arg_begin + arg_offset[row - 1], arg_offset[row] - arg_offset[row - 1]);

size_t data_length = arg_offset[row] - arg_offset[row - 1];

if (data_length == 0) { // The original data is ''

col_offset[row] = col_offset[row - 1];

continue;

}

union {

char bytes[COMPRESS_STR_LENGTH];

uint32_t value;

} length;

std::memcpy(length.bytes, data.data, COMPRESS_STR_LENGTH);

size_t idx = col_data.size();

col_data.resize(col_data.size() + length.value);

uncompressed_slice = Slice(col_data.data() + idx, length.value);

Slice compressed_data(data.data + COMPRESS_STR_LENGTH, data.size - COMPRESS_STR_LENGTH);

auto st = compression_codec->decompress(compressed_data, &uncompressed_slice);

if (!st.ok()) { // is not a legal compressed string

col_data.resize(col_data.size() - length.value); // remove compressed_data

col_offset[row] = col_offset[row - 1];

null_map[row] = true;

continue;

}

col_offset[row] = col_offset[row - 1] + length.value;

}

block.replace_by_position(

result, ColumnNullable::create(std::move(result_column), std::move(null_column)));

return Status::OK();

}

};

void register_function_compress(SimpleFunctionFactory& factory) {

factory.register_function<FunctionCompress>();

factory.register_function<FunctionUncompress>();

}

} // namespace doris