block_allocator

Byte range suballocator in C or Odin, for suballocating GPU heaps, based on the ideas behind Sebastian Aaltonen's OffsetAllocator.

These files are intended as reference implementations to be copied into your own codebase and modified / instrumented as you see fit. test.c and test.odin contain example code which partially tests the allocators for correctness, but they have not been validated beyond that.

Odin Usage

allocator := block_allocator_init(max(u32))
defer block_allocator_destroy(&allocator)
alloc, ok := block_alloc(&allocator, 512)
assert(ok)
block_free(&allocator, &alloc)

C Usage

Include block_allocator.h everywhere it is needed, and #define BLOCK_ALLOCATOR_IMPL in one compilation unit before including the header to pull in the implementation.

block_allocator_t allocator;
block_allocator_init(0xffffffff, &allocator);
block_allocator_allocation_t alloc;
int res = block_allocator_alloc(&allocator, size, &alloc);
assert(ok == BLOCK_ALLOCATOR_SUCCESS);
block_allocator_free(&allocator, &alloc);
block_allocator_destroy(&allocator);

Visualising Heap Fragmentation

I also provide block_allocator_head and block_allocator_next functions, which can be used to traverse the heap in memory order. This is useful for building visualisations of heap fragmentation, in conjuction with block_allocator_is_used to determine if a memory blcok is currently allocated or available.