mirror of
https://github.com/WinampDesktop/winamp.git
synced 2024-12-12 10:31:01 -05:00
112 lines
3.9 KiB
C++
112 lines
3.9 KiB
C++
/*
|
|
* RowVisitor.h
|
|
* ------------
|
|
* Purpose: Class for recording which rows of a song has already been visited, used for detecting when a module starts to loop.
|
|
* Notes : See implementation file.
|
|
* Authors: OpenMPT Devs
|
|
* The OpenMPT source code is released under the BSD license. Read LICENSE for more details.
|
|
*/
|
|
|
|
|
|
#pragma once
|
|
|
|
#include "openmpt/all/BuildSettings.hpp"
|
|
|
|
#include "mpt/base/span.hpp"
|
|
#include "Snd_defs.h"
|
|
|
|
#include <map>
|
|
|
|
OPENMPT_NAMESPACE_BEGIN
|
|
|
|
#if defined(MPT_BUILD_DEBUG) || defined(MPT_BUILD_FUZZER)
|
|
#define MPT_VERIFY_ROWVISITOR_LOOPSTATE
|
|
#endif // MPT_BUILD_DEBUG || MPT_BUILD_FUZZER
|
|
|
|
class CSoundFile;
|
|
class ModSequence;
|
|
struct ModChannel;
|
|
|
|
class RowVisitor
|
|
{
|
|
protected:
|
|
using ChannelStates = mpt::span<const ModChannel>;
|
|
|
|
class LoopState
|
|
{
|
|
static constexpr uint64 FNV1a_BASIS = 14695981039346656037ull;
|
|
static constexpr uint64 FNV1a_PRIME = 1099511628211ull;
|
|
uint64 m_hash = FNV1a_BASIS;
|
|
#ifdef MPT_VERIFY_ROWVISITOR_LOOPSTATE
|
|
std::vector<std::pair<uint8, uint8>> m_counts; // Actual loop counts to verify equality of hash-based implementation
|
|
#endif
|
|
|
|
public:
|
|
LoopState() = default;
|
|
LoopState(const ChannelStates &chnState, const bool ignoreRow);
|
|
LoopState(const LoopState &) = default;
|
|
LoopState(LoopState&&) = default;
|
|
LoopState &operator=(const LoopState &) = default;
|
|
LoopState &operator=(LoopState&&) = default;
|
|
|
|
[[nodiscard]] bool operator==(const LoopState &other) const noexcept
|
|
{
|
|
#ifdef MPT_VERIFY_ROWVISITOR_LOOPSTATE
|
|
if((m_counts == other.m_counts) != (m_hash == other.m_hash))
|
|
std::abort();
|
|
#endif
|
|
return m_hash == other.m_hash;
|
|
}
|
|
|
|
[[nodiscard]] bool HasLoops() const noexcept
|
|
{
|
|
#ifdef MPT_VERIFY_ROWVISITOR_LOOPSTATE
|
|
if(m_counts.empty() != (m_hash == FNV1a_BASIS))
|
|
std::abort();
|
|
#endif
|
|
return m_hash != FNV1a_BASIS;
|
|
}
|
|
};
|
|
|
|
using LoopStateSet = std::vector<LoopState>;
|
|
|
|
// Stores for every (order, row) combination in the sequence if it has been visited or not.
|
|
std::vector<std::vector<bool>> m_visitedRows;
|
|
// Map for each row that's part of a pattern loop which loop states have been visited. Held in a separate data structure because it is sparse data in typical modules.
|
|
std::map<std::pair<ORDERINDEX, ROWINDEX>, LoopStateSet> m_visitedLoopStates;
|
|
|
|
const CSoundFile &m_sndFile;
|
|
ROWINDEX m_rowsSpentInLoops = 0;
|
|
const SEQUENCEINDEX m_sequence;
|
|
|
|
public:
|
|
RowVisitor(const CSoundFile &sndFile, SEQUENCEINDEX sequence = SEQUENCEINDEX_INVALID);
|
|
|
|
void MoveVisitedRowsFrom(RowVisitor &other) noexcept;
|
|
|
|
// Resize / Clear the row vector.
|
|
// If reset is true, the vector is not only resized to the required dimensions, but also completely cleared (i.e. all visited rows are unset).
|
|
void Initialize(bool reset);
|
|
|
|
// Mark an order/row combination as visited and returns true if it was visited before.
|
|
bool Visit(ORDERINDEX ord, ROWINDEX row, const ChannelStates &chnState, bool ignoreRow);
|
|
|
|
// Find the first row that has not been played yet.
|
|
// The order and row is stored in the order and row variables on success, on failure they contain invalid values.
|
|
// If onlyUnplayedPatterns is true (default), only completely unplayed patterns are considered, otherwise a song can start anywhere.
|
|
// Function returns true on success.
|
|
[[nodiscard]] bool GetFirstUnvisitedRow(ORDERINDEX &order, ROWINDEX &row, bool onlyUnplayedPatterns) const;
|
|
|
|
// Pattern loops can stack up exponentially, which can cause an effectively infinite amount of time to be spent on evaluating them.
|
|
// If this function returns true, module evaluation should be aborted because the pattern loops appear to be too complex.
|
|
[[nodiscard]] bool ModuleTooComplex(ROWINDEX threshold) const noexcept { return m_rowsSpentInLoops >= threshold; }
|
|
void ResetComplexity() { m_rowsSpentInLoops = 0; }
|
|
|
|
protected:
|
|
// Get the needed vector size for a given pattern.
|
|
[[nodiscard]] ROWINDEX VisitedRowsVectorSize(PATTERNINDEX pattern) const noexcept;
|
|
|
|
[[nodiscard]] const ModSequence &Order() const;
|
|
};
|
|
|
|
OPENMPT_NAMESPACE_END
|