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#include <init/malloc.h>
#include <shared/flags.h>
#include <shared/syscalls.h>
#include <stdbool.h>
#include <init/stdlib.h>
#define MBLOCK_MAGIC 0x1337BABE
struct mblock {
uint32_t magic;
size_t length; // including this struct
bool used;
struct mblock *next;
};
static struct mblock *first = NULL, *last = NULL;
static struct mblock *expand(size_t size);
void *malloc(size_t size) {
struct mblock *iter = first;
size += sizeof(struct mblock);
while (iter) {
if (!iter->used && iter->length >= size)
break;
iter = iter->next;
}
if (!iter) iter = expand(size);
if (!iter) return NULL;
iter->used = true;
// TODO truncate and split
return &iter[1];
}
void free(void *ptr) {
struct mblock *block = ptr - sizeof(struct mblock);
if (block->magic != MBLOCK_MAGIC) {
// TODO debug log switch
printf("didn't find MBLOCK_MAGIC @ 0x%x\n", block);
return;
}
block->used = false;
}
static struct mblock *expand(size_t size) {
struct mblock *block = _syscall_memflag(0, size, MEMFLAG_PRESENT | MEMFLAG_FINDFREE);
if (!block) return NULL;
block->magic = MBLOCK_MAGIC;
block->length = size;
block->used = false;
block->next = NULL;
if (!first) first = block;
if (last) last->next = block;
last = block;
// TODO collapse
return block;
}
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