50 lines
1.2 KiB
Plaintext
50 lines
1.2 KiB
Plaintext
Os :: #import "os.kl"
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SizeU :: #strict U64
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arena_di: U64
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Arena :: struct
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di: U64 // @debug_id
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memory: Os.Memory
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alignment: U64
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len: U64
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ADDITIONAL_COMMIT_SIZE :: 1024*1024
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DEFAULT_RESERVE_SIZE :: 1024*1024*1024
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DEFAULT_ALIGNMENT :: 8
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clamp_top_sizeu :: (val: SizeU, max: SizeU): SizeU
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if val > max
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return max
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return val
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get_align_offset :: (size: SizeU, align: SizeU): SizeU
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mask := align - 1
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val := size & mask
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if val != 0
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val = align - val
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return val
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align_up :: (size: SizeU, align: SizeU): SizeU
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result := size + get_align_offset(size, align)
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return result
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arena_init :: (a: *Arena)
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a.memory = Os.reserve(a.DEFAULT_RESERVE_SIZE)
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a.alignment = a.DEFAULT_ALIGNMENT
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a.di = arena_di++
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arena_push_size :: (a: *Arena, size: SizeU): *void
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generous_size := size + a.alignment
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if a.len + generous_size > a.memory.commit
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if a.memory.reserve == 0
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arena_init(a)
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result := Os.commit(&a.memory, generous_size + a.ADDITIONAL_COMMIT_SIZE)
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assert(result == true)
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a.len = align_up(a.len, a.alignment)
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assert(a.memory.reserve > a.len + a.memory.commit)
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result: *void = a.memory.data + a.len
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a.len += size
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return result
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