76 lines
2.2 KiB
C
76 lines
2.2 KiB
C
#include "object_pool.h"
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#include "../core/memory.h"
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typedef struct BzObjectPool {
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void *objects;
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size_t stride;
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size_t numObjects;
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i32 firstFree;
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} BzObjectPool;
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BzObjectPool *bzObjectPoolCreate(const BzObjectPoolDesc *desc) {
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BZ_ASSERT(desc->objectSize > 0);
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// NOTE: Since object bits are used as a free list
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// when not in use, we must ensure they can hold i32.
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size_t stride = desc->objectSize;
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if (stride < sizeof(i32)) {
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stride = sizeof(i32);
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}
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size_t numBytes = sizeof(BzObjectPool) + desc->numObjects * stride;
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BzObjectPool *pool = bzAlloc(numBytes);
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*pool = (BzObjectPool) {
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.objects=pool + 1,
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.stride=stride,
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.numObjects=desc->numObjects,
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.firstFree=0,
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};
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// Link free list
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for (size_t i = 0; i < pool->numObjects - 1; i++) {
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i32 *object = bzObjectPoolGetObject(pool, i);
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*object = (i32) (i + 1);
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}
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i32 *lastObject = bzObjectPoolGetObject(pool, pool->numObjects - 1);
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*lastObject = -1;
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return pool;
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}
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void bzObjectPoolDestroy(BzObjectPool *pool) {
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bzFree(pool);
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}
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size_t bzObjectPoolCalcNumFree(BzObjectPool *pool) {
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size_t count = 0;
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i32 idx = pool->firstFree;
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while (idx != -1) {
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count++;
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i32 *object = bzObjectPoolGetObject(pool, idx);
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idx = *object;
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}
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return count;
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}
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void *bzObjectPool(BzObjectPool *pool) {
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if (pool->firstFree == -1)
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return NULL;
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i32 *object = bzObjectPoolGetObject(pool, pool->firstFree);
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pool->firstFree = *object;
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return object;
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}
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void *bzObjectPoolGetObject(BzObjectPool *pool, i32 idx) {
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BZ_ASSERT(idx >= 0 && (size_t) idx < pool->numObjects);
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return (void *) ((u8 *) pool->objects + idx * pool->stride);
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}
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i32 bzObjectPoolGetIdx(BzObjectPool *pool, void *object) {
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size_t objectIdx = (size_t) object - (size_t) pool->objects;
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return (i32) (objectIdx / pool->stride);
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}
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void bzObjectPoolRelease(BzObjectPool *pool, void *object) {
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size_t objectIdx = bzObjectPoolGetIdx(pool, object);
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BZ_ASSERT(objectIdx < pool->numObjects);
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*(i32 *) ((u8 *) pool->objects + objectIdx * pool->stride) = pool->firstFree;
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pool->firstFree = (i32) objectIdx;
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}
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