Nils O. Selåsdal
112 lines
2.9 KiB
C
112 lines
2.9 KiB
C
#include <assert.h>
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#include "ucore/spool.h"
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#include "ucore/utils.h"
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#include <string.h>
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void uc_pool_init(UCPool *pool, void *buffer, size_t buffer_size, size_t block_size, size_t align)
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{
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assert(align > 0);
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assert((align & (align - 1)) == 0); // power of 2
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// enforce minimum for storing free list pointers
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if (align < _Alignof(unsigned char *)) {
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align = _Alignof(unsigned char *);
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}
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if (block_size < sizeof(unsigned char *)) {
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block_size = sizeof(unsigned char *);
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}
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// ensure initial alignment
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size_t stride = UC_ALIGN(block_size, align);
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// align first usable block
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uintptr_t start_addr = (uintptr_t)buffer;
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uintptr_t first_addr = UC_ALIGN(start_addr, align);
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size_t padding = first_addr - start_addr;
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if (padding + stride > buffer_size) {
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pool->capacity = 0;
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pool->free_list = NULL;
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} else {
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size_t usable = buffer_size - padding;
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pool->capacity = usable / stride;
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// build intrusive free list
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unsigned char *p = (unsigned char *)first_addr;
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for (size_t i = 0; i < pool->capacity - 1; ++i) {
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*(unsigned char **)p = p + stride;
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p += stride;
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}
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*(unsigned char **)p = NULL; // last element
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pool->free_list = (unsigned char *)first_addr;
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}
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pool->block_size = stride;
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pool->align = align;
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pool->start = (unsigned char *)buffer;
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pool->end = (unsigned char *)buffer + buffer_size;
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}
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void *uc_pool_alloc(UCPool *pool)
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{
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if (!pool->free_list) {
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return NULL;
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}
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unsigned char *block = pool->free_list;
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pool->free_list = *(unsigned char **)block;
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#ifdef DEBUG
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memset(block, 0xCB, pool->block_size);
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#endif
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return block;
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}
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#include <stdio.h>
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void uc_pool_free(UCPool *pool, void *p)
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{
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if (p == NULL) {
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return;
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}
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#ifdef DEBUG
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assert((unsigned char *)p >= pool->start && (unsigned char*)p < pool->end);
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assert(((uintptr_t)p - (uintptr_t)pool->start) % pool->block_size == 0);
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// double-free detection
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for (unsigned char *f = pool->free_list; f; f = *(unsigned char**)f) {
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if (f == p) {
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assert(0 && "Double free detected in pool!");
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return;
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}
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}
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memset(p, 0xDD, pool->block_size);
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#endif
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// When not in use, store pointer to next free element inline in the block
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*(unsigned char **)p = pool->free_list;
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pool->free_list = p;
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}
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void uc_pool_reset(UCPool *pool)
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{
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if (pool->capacity == 0)
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return;
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uintptr_t start_addr = (uintptr_t)pool->start;
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uintptr_t first_addr = UC_ALIGN(start_addr, pool->align);
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unsigned char *p = (unsigned char *)first_addr;
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// build intrusive free list
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for (size_t i = 0; i < pool->capacity - 1; ++i) {
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*(unsigned char **)p = p + pool->block_size;
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p += pool->block_size;
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}
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*(unsigned char **)p = NULL; // last element
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pool->free_list = (unsigned char *)first_addr;
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}
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