123 lines
1.8 KiB
C
123 lines
1.8 KiB
C
#include <stdlib.h>
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#include <stdio.h>
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#define MAX_I 0x00ffffff
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#define bool char
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#define TRUE 1
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#define FALSE 0
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struct object_s {
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char val;
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};
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struct block_s {
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struct block_s *next;
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struct block_s *prev;
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struct object_s obj;
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};
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static struct block_s pool[MAX_I];
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static struct block_s *free_pool = NULL,
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*busy_pool = NULL;
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/*
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* инициализация пула
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*/
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void init()
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{
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size_t i;
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size_t max_i = MAX_I - 1;
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for (i = 1; i < max_i; i++) {
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pool[i].prev = &pool[i - 1];
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pool[i].next = &pool[i + 1];
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}
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pool[0].prev = NULL;
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pool[0].next = &pool[1];
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pool[MAX_I - 1].prev = &pool[MAX_I - 2];
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pool[MAX_I - 1].next = NULL;
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free_pool = &pool[0];
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busy_pool = NULL;
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}
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inline void *pool_alloc()
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{
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if (!free_pool)
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return NULL;
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free_pool->prev = free_pool->next; // save free_pool->next in free_pool->prev
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free_pool->next = busy_pool;
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if (busy_pool)
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busy_pool->prev = free_pool;
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busy_pool = free_pool;
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free_pool = free_pool->prev;
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busy_pool->prev = NULL; // saved in free_pool->prev to NULL
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return &busy_pool->obj;
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}
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inline void pool_free(void *p)
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{
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if (!p)
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return;
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struct block_s *b1 = (struct block_s *)(p - 2 * sizeof(struct block_s *)),
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*b0 = b1->prev,
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*b2 = b1->next,
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*f1 = free_pool;
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// cut block from free list
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if (b0)
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b0->next = b2;
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if (b2)
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b2->prev = b0;
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// f1, b1
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if (f1) {
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b1->next = f1;
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f1->prev = b1;
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}
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else
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b1->next = NULL;
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// free_pool
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free_pool = b2;
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// busy_pool
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if (busy_pool == b1)
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busy_pool = b2;
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}
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void *mem[MAX_I];
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int main()
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{
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unsigned long long i;
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init();
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for (i = 0; i < MAX_I; i++)
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if (!(mem[i] = pool_alloc())) {
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printf("не удалось выделить память под %lld блок\n", i);
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break;
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}
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for (i = 0; i < MAX_I; i++)
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pool_free(mem[i]);
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return 0;
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}
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