89 lines
2.1 KiB
C
89 lines
2.1 KiB
C
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#include "log.h"
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#include <stddef.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/types.h>
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#define MAX_ALLOCS 256
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struct Alloc {
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void *start;
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uint size;
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struct Alloc *next;
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};
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struct Mem {
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void *mem;
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size_t mem_size;
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uint count;
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struct Alloc *alloc;
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struct Alloc allocs[MAX_ALLOCS];
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};
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struct Mem *make_mem(size_t size) {
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struct Mem *mem = malloc(sizeof(struct Mem));
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mem->mem_size = size;
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mem->mem = malloc(mem->mem_size);
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memset(mem->mem, 0, mem->mem_size);
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mem->count = 0;
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memset(&mem->allocs, 0, sizeof(struct Alloc) * MAX_ALLOCS);
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mem->allocs[0] = (struct Alloc){mem->mem + mem->mem_size, 0, NULL};
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mem->allocs[1] = (struct Alloc){mem->mem, 0, &mem->allocs[0]};
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mem->alloc = &mem->allocs[1];
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return mem;
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}
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void uninit_mem(struct Mem *mem) {
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free(mem->mem);
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free(mem);
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}
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static struct Alloc *get_next_alloc(struct Mem *mem) {
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uint index = mem->count;
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mem->count++;
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while (*(char *)&mem->allocs[mem->count] != 0) {
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mem->count++;
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if (mem->count >= MAX_ALLOCS) {
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crash("out of allocs!");
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}
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}
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return &mem->allocs[index];
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}
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void *mem_malloc(struct Mem *mem, size_t size) {
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struct Alloc *prev = mem->alloc;
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while (prev->next != NULL) {
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struct Alloc *next = prev->next;
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if (next->start - (prev->start + prev->size) > size) {
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struct Alloc *new = get_next_alloc(mem);
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*new = (struct Alloc){
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prev->start + prev->size,
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size,
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next,
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};
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prev->next = new;
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meow("MALLOC %p of size %zu, prev is at %p with size %u", new->start,
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size, prev->start, prev->size);
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/* print_backtrace(); */
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return new->start;
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} else {
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prev = next;
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}
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}
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crash("no big enaugh free space found!");
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return NULL;
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}
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void mem_free(struct Mem *mem, void *p) {
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struct Alloc *current = mem->alloc;
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struct Alloc *prev = mem->alloc;
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while (p < current->start) {
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prev = current;
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current = current->next;
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}
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prev->next = current->next;
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int index = current - mem->allocs;
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if (index < mem->count) {
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mem->count = index;
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}
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memset(&mem->allocs[index], 0, sizeof(struct Alloc));
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}
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