92 lines
1.4 KiB
D
92 lines
1.4 KiB
D
import core.stdc.stdio : Printf = printf;
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version(linux)
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{
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import core.sys.posix.sys.mman;
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void*
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MemAlloc(u64 size)
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{
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return mmap(null, size, PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, -1, 0);
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}
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void
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MemFree(void* ptr, u64 size)
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{
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assert(munmap(ptr, size) == 0, "MemFree failure");
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}
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}
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struct Arena
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{
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u8* mem;
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u64 length;
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u64 pos;
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};
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Arena
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CreateArena(u64 size)
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{
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Arena arena = {
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mem: cast(u8 *)MemAlloc(size),
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length: size,
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pos: 0,
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};
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assert(arena.mem != null, "Unable to allocate memory for arena");
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return arena;
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};
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T[]
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AllocArray(T)(Arena* arena, u64 count)
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{
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void* mem = AllocAlign(arena, T.sizeof * count, DEFAULT_ALIGNMENT);
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memset(mem, 0, T.sizeof * count);
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return (cast(T*)mem)[0 .. count];
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}
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T*
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Alloc(T)(Arena* arena)
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{
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void* mem = AllocAlign(arena, T.sizeof, DEFAULT_ALIGNMENT);
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memset(mem, 0, T.sizeof);
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return cast(T*)mem;
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};
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void*
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AllocAlign(Arena* arena, u64 size, u64 alignment)
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{
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void* ptr = null;
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uintptr mem_pos = cast(uintptr)arena.mem;
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uintptr current = mem_pos + arena.pos;
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uintptr offset = AlignPow2(current, alignment) - mem_pos;
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if (offset+size <= arena.length)
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{
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ptr = &arena.mem[offset];
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arena.pos = offset+size;
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}
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else
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{
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Printf("AllocAlign failure: out of memory, size requested: %llu", size);
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assert(0);
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}
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return ptr;
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};
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void
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Reset(Arena* arena)
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{
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arena.pos = 0;
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}
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void
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Free(Arena* arena)
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{
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(arena.mem);
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}
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