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#pragma clang system_header
// 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.
#pragma once
#include <cstdint>
#include <memory>
#include "contrib/libs/apache/arrow_next/cpp/src/arrow/buffer.h"
#include "contrib/libs/apache/arrow_next/cpp/src/arrow/memory_pool.h"
#include "contrib/libs/apache/arrow_next/cpp/src/arrow/result.h"
#include "contrib/libs/apache/arrow_next/cpp/src/arrow/util/bit_util.h"
#include "contrib/libs/apache/arrow_next/cpp/src/arrow/util/visibility.h"
namespace arrow20 {
namespace internal {
// A std::generate() like function to write sequential bits into a bitmap area.
// Bits preceding the bitmap area are preserved, bits following the bitmap
// area may be clobbered.
template <class Generator>
void GenerateBits(uint8_t* bitmap, int64_t start_offset, int64_t length, Generator&& g) {
if (length == 0) {
return;
}
uint8_t* cur = bitmap + start_offset / 8;
uint8_t bit_mask = bit_util::kBitmask[start_offset % 8];
uint8_t current_byte = *cur & bit_util::kPrecedingBitmask[start_offset % 8];
for (int64_t index = 0; index < length; ++index) {
const bool bit = g();
current_byte = bit ? (current_byte | bit_mask) : current_byte;
bit_mask = static_cast<uint8_t>(bit_mask << 1);
if (bit_mask == 0) {
bit_mask = 1;
*cur++ = current_byte;
current_byte = 0;
}
}
if (bit_mask != 1) {
*cur++ = current_byte;
}
}
// Like GenerateBits(), but unrolls its main loop for higher performance.
template <class Generator>
void GenerateBitsUnrolled(uint8_t* bitmap, int64_t start_offset, int64_t length,
Generator&& g) {
static_assert(std::is_same<decltype(std::declval<Generator>()()), bool>::value,
"Functor passed to GenerateBitsUnrolled must return bool");
if (length == 0) {
return;
}
uint8_t current_byte;
uint8_t* cur = bitmap + start_offset / 8;
const uint64_t start_bit_offset = start_offset % 8;
uint8_t bit_mask = bit_util::kBitmask[start_bit_offset];
int64_t remaining = length;
if (bit_mask != 0x01) {
current_byte = *cur & bit_util::kPrecedingBitmask[start_bit_offset];
while (bit_mask != 0 && remaining > 0) {
current_byte |= g() * bit_mask;
bit_mask = static_cast<uint8_t>(bit_mask << 1);
--remaining;
}
*cur++ = current_byte;
}
int64_t remaining_bytes = remaining / 8;
uint8_t out_results[8];
while (remaining_bytes-- > 0) {
for (int i = 0; i < 8; ++i) {
out_results[i] = g();
}
*cur++ = static_cast<uint8_t>(out_results[0] | out_results[1] << 1 |
out_results[2] << 2 | out_results[3] << 3 |
out_results[4] << 4 | out_results[5] << 5 |
out_results[6] << 6 | out_results[7] << 7);
}
int64_t remaining_bits = remaining % 8;
if (remaining_bits) {
current_byte = 0;
bit_mask = 0x01;
while (remaining_bits-- > 0) {
current_byte |= g() * bit_mask;
bit_mask = static_cast<uint8_t>(bit_mask << 1);
}
*cur++ = current_byte;
}
}
} // namespace internal
} // namespace arrow20
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