mirror of
https://github.com/ecency/ecency-mobile.git
synced 2024-12-23 13:22:02 +03:00
101 lines
2.1 KiB
C++
101 lines
2.1 KiB
C++
/*
|
|
* Copyright 2016 Facebook, Inc.
|
|
*
|
|
* Licensed 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 <stddef.h>
|
|
|
|
namespace folly {
|
|
|
|
template <typename T>
|
|
class GroupVarint;
|
|
|
|
namespace detail {
|
|
|
|
template <typename T>
|
|
struct GroupVarintTraits;
|
|
|
|
template <>
|
|
struct GroupVarintTraits<uint32_t> {
|
|
enum {
|
|
kGroupSize = 4,
|
|
kHeaderSize = 1,
|
|
};
|
|
};
|
|
|
|
template <>
|
|
struct GroupVarintTraits<uint64_t> {
|
|
enum {
|
|
kGroupSize = 5,
|
|
kHeaderSize = 2,
|
|
};
|
|
};
|
|
|
|
template <typename T>
|
|
class GroupVarintBase {
|
|
protected:
|
|
typedef GroupVarintTraits<T> Traits;
|
|
enum { kHeaderSize = Traits::kHeaderSize };
|
|
|
|
public:
|
|
typedef T type;
|
|
|
|
/**
|
|
* Number of integers encoded / decoded in one pass.
|
|
*/
|
|
enum { kGroupSize = Traits::kGroupSize };
|
|
|
|
/**
|
|
* Maximum encoded size.
|
|
*/
|
|
enum { kMaxSize = kHeaderSize + sizeof(type) * kGroupSize };
|
|
|
|
/**
|
|
* Maximum size for n values.
|
|
*/
|
|
static size_t maxSize(size_t n) {
|
|
// Full groups
|
|
size_t total = (n / kGroupSize) * kFullGroupSize;
|
|
// Incomplete last group, if any
|
|
n %= kGroupSize;
|
|
if (n) {
|
|
total += kHeaderSize + n * sizeof(type);
|
|
}
|
|
return total;
|
|
}
|
|
|
|
/**
|
|
* Size of n values starting at p.
|
|
*/
|
|
static size_t totalSize(const T* p, size_t n) {
|
|
size_t size = 0;
|
|
for (; n >= kGroupSize; n -= kGroupSize, p += kGroupSize) {
|
|
size += Derived::size(p);
|
|
}
|
|
if (n) {
|
|
size += Derived::partialSize(p, n);
|
|
}
|
|
return size;
|
|
}
|
|
|
|
private:
|
|
typedef GroupVarint<T> Derived;
|
|
enum { kFullGroupSize = kHeaderSize + kGroupSize * sizeof(type) };
|
|
};
|
|
|
|
} // namespace detail
|
|
} // namespace folly
|