153 lines
3.8 KiB
C++
153 lines
3.8 KiB
C++
//- sixten: Common memory functions
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static void Copy(void *Dest, void *Source, umm Count)
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{
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u8 *Dest8 = (u8 *)Dest;
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u8 *Source8 = (u8 *)Source;
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while(Count--)
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{
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*Dest8++ = *Source8++;
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}
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}
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static void Fill(void *Dest, u8 Value, umm Count)
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{
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u8 *Dest8 = (u8 *)Dest;
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while(Count--)
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{
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*Dest8++ = Value;
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}
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}
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//- sixten: Memory arena functions
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static void Release(memory_arena *Arena)
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{
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while(Arena->CurrentBlock != 0)
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{
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platform_memory_block *MemoryBlock = Arena->CurrentBlock;
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b32 IsLastBlock = (MemoryBlock->ArenaPrev == 0);
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Arena->CurrentBlock = MemoryBlock->ArenaPrev;
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Platform.DeallocateMemory(MemoryBlock);
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if(IsLastBlock)
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{
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break;
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}
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}
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}
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inline umm GetAlignmentOffset(memory_arena *Arena, umm Alignment)
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{
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umm AlignmentOffset = 0;
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umm ResultPointer = (umm)Arena->CurrentBlock + Arena->CurrentBlock->Used;
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umm AlignmentMask = Alignment - 1;
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if(ResultPointer & AlignmentMask)
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{
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AlignmentOffset = Alignment - (ResultPointer & AlignmentMask);
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}
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return(AlignmentOffset);
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}
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inline umm GetEffectiveSizeFor(memory_arena *Arena, umm InitialSize, arena_push_params Params)
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{
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umm Size = InitialSize;
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umm AlignmentOffset = GetAlignmentOffset(Arena, Params.Alignment);
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Size += AlignmentOffset;
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return(Size);
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}
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static void *PushSize_(memory_arena *Arena, umm InitialSize, arena_push_params Params)
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{
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void *Result = 0;
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umm Size = 0;
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if(Arena->CurrentBlock)
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{
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Size = GetEffectiveSizeFor(Arena, InitialSize, Params);
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}
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if(!Arena->CurrentBlock || ((Arena->CurrentBlock->Used + Size) > Arena->CurrentBlock->Size))
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{
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Size = InitialSize;
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if(!Arena->MinimumBlockSize)
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{
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Arena->MinimumBlockSize = 1024*1024;
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}
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umm BlockSize = Maximum(Size, Arena->MinimumBlockSize);
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platform_memory_block *NewBlock = Platform.AllocateMemory(BlockSize);
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NewBlock->ArenaPrev = Arena->CurrentBlock;
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Arena->CurrentBlock = NewBlock;
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}
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Assert((Arena->CurrentBlock->Used + Size) <= Arena->CurrentBlock->Size);
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umm AlignmentOffset = GetAlignmentOffset(Arena, Params.Alignment);
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umm OffsetInBlock = Arena->CurrentBlock->Used + AlignmentOffset;
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Result = Arena->CurrentBlock->Base + OffsetInBlock;
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Arena->CurrentBlock->Used += Size;
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Assert(Size >= InitialSize);
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Assert(Arena->CurrentBlock->Used <= Arena->CurrentBlock->Size);
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if(Params.Flags & ArenaFlag_ClearToZero)
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{
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Fill(Result, 0, InitialSize);
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}
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return(Result);
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}
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//- sixten: Bootsrapping helpers
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static void *BootstrapPushSize(umm Size, umm OffsetToArena)
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{
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memory_arena Arena = {};
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void *Result = PushSize(&Arena, Size);
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*(memory_arena *)((u8 *)Result + OffsetToArena) = Arena;
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return(Result);
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}
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//- sixten: Temporary memory functions
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static temporary_memory BeginTemporaryMemory(memory_arena *Arena)
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{
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temporary_memory Result;
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Result.Arena = Arena;
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Result.Block = Arena->CurrentBlock;
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Result.Used = Arena->CurrentBlock ? Arena->CurrentBlock->Used : 0;
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++Arena->TemporaryMemoryCount;
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return(Result);
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}
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static void EndTemporaryMemory(temporary_memory Temp)
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{
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memory_arena *Arena = Temp.Arena;
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while(Arena->CurrentBlock != Temp.Block)
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{
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platform_memory_block *MemoryBlock = Arena->CurrentBlock;
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Arena->CurrentBlock = MemoryBlock->ArenaPrev;
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Platform.DeallocateMemory(MemoryBlock);
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}
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if(Arena->CurrentBlock)
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{
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Assert(Arena->CurrentBlock->Used >= Temp.Used);
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Arena->CurrentBlock->Used = Temp.Used;
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}
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Assert(Arena->TemporaryMemoryCount > 0);
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--Arena->TemporaryMemoryCount;
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} |