97 lines
3.1 KiB
C
97 lines
3.1 KiB
C
#ifndef INCLUDED_C_BUDDYALLOCATOR_H
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#define INCLUDED_C_BUDDYALLOCATOR_H
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#ifndef INCLUDED_C_BUDDY_H
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#include <c_Buddy.h>
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#endif /*INCLUDED_C_BUDDY_H*/
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#ifndef INCLUDED_C_ALLOCATOR_H
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#include <c_Allocator.h>
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#endif /*INCLUDED_C_ALLOCATOR_H*/
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/* ------------------------------------------------------------------------------------------------------------------ */
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/* */
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typedef struct {
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c_Buddy_t* buddy;
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}c_BuddyAllocator_t;
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C_STATIC_FORCE_INLINE
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void c_BuddyAllocator_Init(c_BuddyAllocator_t* allocator, c_Buddy_t* buddy) {
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allocator->buddy = buddy;
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}
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/* ------------------------------------------------------------------------------------------------------------------ */
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/* */
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C_STATIC_FORCE_INLINE
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C_ALLOCATOR_ALLOC_FN(c_BuddyAllocator_Alloc) {
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c_BuddyAllocator_t* self = (c_BuddyAllocator_t*)ud;
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if (!self || !self->buddy) return NULL;
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return c_Buddy_Alloc(self->buddy, (int)nBytes);
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}
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C_STATIC_FORCE_INLINE
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C_ALLOCATOR_FREE_FN(c_BuddyAllocator_Free) {
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c_BuddyAllocator_t* self = (c_BuddyAllocator_t*)ud;
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if (!self || !self->buddy) return;
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c_Buddy_Free(self->buddy, ptr);
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}
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C_STATIC_FORCE_INLINE
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C_ALLOCATOR_REALLOC_FN(c_BuddyAllocator_Realloc) {
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c_BuddyAllocator_t* self = (c_BuddyAllocator_t*)ud;
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if (!self || !self->buddy) return NULL;
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// 情况 1: 指针为空，直接分配新内存
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if (!ptr) {
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return c_Buddy_Alloc(self->buddy, (int)nNewSize);
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}
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// 情况 2: 新大小为 0，直接释放内存
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if (nNewSize==0) {
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c_Buddy_Free(self->buddy, ptr);
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return NULL;
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}
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// 核心优化：利用 Header 逆向获取该块在底层伙伴系统中的真实物理大小
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const c_BuddyBlock_t *block = (c_BuddyBlock_t *) ((uint8_t *) ptr - self->buddy->alignment);
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const int actual_block_size = block->size;
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// 【就地复用判定】：如果新申请的大小没有超过当前伙伴块的物理承载上限，并且新大小不至于小到需要缩容割裂
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// 直接返回原指针，零拷贝，零内存搬迁！
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if ((int)nNewSize <= actual_block_size && (int)nNewSize > (actual_block_size / 2)) {
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return ptr;
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}
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// 情况 3: 伙伴块大小不匹配（需要升级或降级阶数），申请新块
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void* new_ptr = c_Buddy_Alloc(self->buddy, (int)nNewSize);
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if (!new_ptr) return NULL;
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// 计算安全的拷贝长度
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const c_size_t copy_size = ((c_size_t)actual_block_size < nNewSize) ? (c_size_t)actual_block_size : nNewSize;
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// 数据迁移
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memcpy(new_ptr, ptr, copy_size);
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// 释放旧伙伴块
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c_Buddy_Free(self->buddy, ptr);
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return new_ptr;
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}
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/* ------------------------------------------------------------------------------------------------------------------ */
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/* */
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C_STATIC_FORCE_INLINE
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c_Allocator_t c_BuddyAllocator_Build(c_BuddyAllocator_t* self, c_Buddy_t* buddy) {
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c_BuddyAllocator_Init(self, buddy);
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c_Allocator_t allocator={0};
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allocator.ud = self;
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allocator.alloc = c_BuddyAllocator_Alloc;
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allocator.free = c_BuddyAllocator_Free;
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allocator.realloc = c_BuddyAllocator_Realloc;
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return allocator;
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}
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#endif /*INCLUDED_C_BUDDYALLOCATOR_H*/
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