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util: impl::AvailableIndexFinder

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Michael Scire 2021-02-03 17:47:32 -08:00
parent c0e3cee657
commit 201b17f100
2 changed files with 222 additions and 0 deletions
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2
libraries/libvapours/include/vapours/util.hpp
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@ -46,6 +46,8 @@
#include <vapours/util/util_format_string.hpp> #include <vapours/util/util_format_string.hpp>
#include <vapours/util/util_range.hpp> #include <vapours/util/util_range.hpp>
#include <vapours/util/impl/util_available_index_finder.hpp>
#ifdef ATMOSPHERE_IS_STRATOSPHERE #ifdef ATMOSPHERE_IS_STRATOSPHERE
#include <vapours/util/util_mutex_utils.hpp> #include <vapours/util/util_mutex_utils.hpp>
#endif #endif

220
libraries/libvapours/include/vapours/util/impl/util_available_index_finder.hpp Normal file
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@ -0,0 +1,220 @@
/*
* Copyright (c) 2018-2020 Atmosphère-NX
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
#include <vapours/common.hpp>
#include <vapours/assert.hpp>
#include <vapours/util/util_fourcc.hpp>
namespace ams::util::impl {
class AvailableIndexFinder {
private:
static constexpr int MaxDepthOfBox = 5;
struct BitFlags64 {
private:
u64 m_data;
public:
constexpr ALWAYS_INLINE bool GetFlag(int index) const {
AMS_ASSERT(index < 64);
return ((m_data >> index) & UINT64_C(1)) != 0;
}
constexpr ALWAYS_INLINE void SetFlag(int index) {
AMS_ASSERT(index < 64);
m_data |= (UINT64_C(1) << index);
}
constexpr ALWAYS_INLINE void ClearFlag(int index) {
AMS_ASSERT(index < 64);
m_data &= ~(UINT64_C(1) << index);
}
constexpr ALWAYS_INLINE bool IsFull() const {
return m_data == ~(UINT64_C(0));
}
constexpr ALWAYS_INLINE int FindIndexOfBitZero() const {
AMS_ASSERT(!this->IsFull());
return __builtin_ctzll(~m_data);
}
};
private:
int *m_p_current_index;
int *m_p_map_index;
void *m_buffer;
int m_depth;
BitFlags64 *m_flags;
private:
static constexpr int Pow64(int e) {
switch (e) {
case 0: return 0x1;
case 1: return 0x40;
case 2: return 0x1000;
case 3: return 0x40000;
case 4: return 0x1000000;
case 5: return 0x40000000;
default: return -1;
}
}
static constexpr u64 Roundup64(u64 value) {
return (value + (64 - 1)) / 64;
}
static constexpr size_t GetRequiredNumOfBox(int depth, size_t num_elements) {
if (depth == 1) {
return Roundup64(num_elements);
} else if (depth == 2) {
return Roundup64(num_elements) + Pow64(0);
} else if (depth == 3) {
return Roundup64(num_elements) + Pow64(0) + Pow64(1) + Pow64(2);
} else if (depth == 4) {
return Roundup64(num_elements) + Pow64(0) + Pow64(1) + Pow64(2) + Pow64(3);
} else if (depth == 5) {
return Roundup64(num_elements) + Pow64(0) + Pow64(1) + Pow64(2) + Pow64(3) + Pow64(4);
} else {
return 0;
}
}
static constexpr int CalcOffset(int *arr, int depth) {
int offset = 0;
for (auto i = 0; i < depth; ++i) {
offset += Pow64(i);
}
for (auto i = 0; i < depth; ++i) {
offset += Pow64(i) - arr[depth - 1 - i];
}
return offset;
}
public:
static consteval int GetSignature() {
return static_cast<int>(util::ReverseFourCC<'B', 'I', 'T', 'S'>::Code);
}
static constexpr int GetNeedDepth(size_t num_elements) {
if (num_elements <= 0x40) {
return 1;
} else if (num_elements <= 0x1000) {
return 2;
} else if (num_elements <= 0x40000) {
return 3;
} else if (num_elements <= 0x1000000) {
return 4;
} else if (num_elements <= 0x40000000) {
return 5;
} else {
return -1;
}
}
static constexpr size_t GetRequiredMemorySize(size_t num_elements) {
return sizeof(BitFlags64) * GetRequiredNumOfBox(GetNeedDepth(num_elements), num_elements);
}
public:
void Initialize(int *cur, int *map, u8 *buf) {
const size_t num_elements = static_cast<size_t>(*map);
AMS_ASSERT(num_elements <= static_cast<size_t>(Pow64(MaxDepthOfBox - 1)));
/* Set fields. */
m_p_current_index = cur;
m_p_map_index = map;
m_buffer = buf;
m_depth = GetNeedDepth(num_elements);
/* Validate fields. */
AMS_ASSERT(m_depth > 0);
/* Setup memory. */
std::memset(m_buffer, 0, GetRequiredMemorySize(num_elements));
m_flags = reinterpret_cast<BitFlags64 *>(m_buffer);
}
int AcquireIndex() {
/* Validate pre-conditions. */
AMS_ASSERT(*m_p_current_index < *m_p_map_index);
/* Build up arrays. */
int table[MaxDepthOfBox];
BitFlags64 *pos[MaxDepthOfBox];
for (auto i = 0; i < m_depth; ++i) {
/* Determine the position. */
pos[i] = std::addressof(m_flags[CalcOffset(table, i)]);
/* Set table entry. */
table[i] = pos[i]->FindIndexOfBitZero();
AMS_ASSERT(table[i] != BITSIZEOF(u64));
}
/* Validate that the index is not acquired. */
AMS_ASSERT(!pos[m_depth - 1]->GetFlag(table[m_depth - 1]));
/* Acquire the index. */
pos[m_depth - 1]->SetFlag(table[m_depth - 1]);
/* Validate that the index was acquired. */
AMS_ASSERT(pos[m_depth - 1]->GetFlag(table[m_depth - 1]));
/* Update tracking flags. */
for (auto i = m_depth - 1; i > 0; --i) {
if (pos[i]->IsFull()) {
pos[i - 1]->SetFlag(table[i - 1]);
}
}
/* Calculate the index we acquired. */
int index = 0, pow = 0;
for (auto i = m_depth; i > 0; --i, ++pow) {
index += Pow64(pow) * table[i - 1];
}
/* Increment current index. */
++(*m_p_current_index);
return index;
}
void ReleaseIndex(int index) {
/* Convert index to table. */
int table[MaxDepthOfBox];
for (auto i = 0; i < m_depth; ++i) {
table[m_depth - 1 - i] = index % BITSIZEOF(u64);
index /= BITSIZEOF(u64);
}
/* Build up arrays. */
BitFlags64 *pos[MaxDepthOfBox];
for (auto i = 0; i < m_depth; ++i) {
/* Determine the position. */
pos[i] = std::addressof(m_flags[CalcOffset(table, i)]);
}
/* Validate that the flag is set. */
AMS_ASSERT(pos[m_depth - 1]->GetFlag(table[m_depth - 1]));
/* Clear the flags. */
for (auto i = m_depth - 1; i >= 0; --i) {
pos[i]->ClearFlag(table[i]);
}
/* Decrement current index. */
--(*m_p_current_index);
}
};
}