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#include "mem.h"
#include <stddef.h>
#include <stdint.h>
#include <string.h>
#include "log.h"
#ifndef DEFAULT_ALIGNMENT
#define DEFAULT_ALIGNMENT (2 * sizeof(void*))
#endif
// --- Arena
void* arena_alloc_align(arena* a, size_t size, size_t align) {
ptrdiff_t padding = -(uintptr_t)a->curr & (align - 1);
ptrdiff_t available = a->end - a->curr - padding;
// TRACE("Padding %td available %td", padding, available);
if (available < 0 || (ptrdiff_t)size > available) {
ERROR_EXIT("Arena ran out of memory\n");
}
void* p = a->curr + padding;
a->curr += padding + size;
return memset(p, 0, size);
}
void* arena_alloc(arena* a, size_t size) { return arena_alloc_align(a, size, DEFAULT_ALIGNMENT); }
arena arena_create(void* backing_buffer, size_t capacity) {
return (arena){ .begin = backing_buffer,
.curr = backing_buffer,
.end = backing_buffer + (ptrdiff_t)capacity };
}
void arena_free_all(arena* a) {
a->curr = a->begin; // pop everything at once and reset to the start.
}
void arena_free_storage(arena* a) { free(a->begin); }
arena_save arena_savepoint(arena* a) {
arena_save savept = { .arena = a, .savepoint = a->curr };
return savept;
}
void arena_rewind(arena_save savepoint) { savepoint.arena->curr = savepoint.savepoint; }
// --- Pool
void_pool void_pool_create(arena* a, u64 capacity, u64 entry_size) {
size_t memory_requirements = capacity * entry_size;
void* backing_buf = arena_alloc(a, memory_requirements);
void_pool pool = { .capacity = capacity,
.entry_size = entry_size,
.count = 0,
.backing_buffer = backing_buf,
.free_list_head = NULL };
void_pool_free_all(&pool);
return pool;
}
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