/**
* Free memory
*/
void free(void* pos) {
uint32_t* block = reinterpret_cast<uint32_t*>(pos);
block--;
if (!is_allocated(next_block(block))) {
uint32_t new_size = size_of_block(block) + 4 + size_of_block(next_block(block));
record(block, new_size, kFree);
} else {
record(block, size_of_block(block), kFree);
}
}
/**
* Allocate memory
*/
void* alloc(uint32_t size) {
// aligned 2
if (size & 0b1) size += 1;
void* cur = mstart_;
for (; cur != mend_; cur = next_block(cur)) {
uint32_t block_size = size_of_block(cur);
if (block_size >= size && !is_allocated(cur)) {
void* remain = slice_block(cur, size);
uint32_t remain_size = block_size - 4 - size; // 4 bytes is for header
if (remain_size > 0) {
record(cur, size, kAllocated);
record(remain, remain_size, kFree);
} else {
record(cur, block_size, kAllocated);
}
return reinterpret_cast<uint8_t*>(cur) + 4;
}
}
return nullptr;
}
void* next_block(void* block) const {
uint32_t p_value = reinterpret_cast<uint32_t>(block);
p_value += size_of_block(block) + 4;
return reinterpret_cast<void*>(p_value);
}
int main(int argc, char**argv)
{
void *heapA;
void *pointers[TESTSIZE];
xbt_init(&argc,argv);
XBT_INFO("Allocating a new heap");
heapA = xbt_mheap_new(-1, ((char*)sbrk(0)) + BUFFSIZE);
if (heapA == NULL) {
perror("attach 1 failed");
fprintf(stderr, "bye\n");
exit(1);
}
XBT_INFO("HeapA allocated");
int i, size;
for (i = 0; i < TESTSIZE; i++) {
size = size_of_block(i);
pointers[i] = mmalloc(heapA, size);
XBT_INFO("%d bytes allocated with offset %tx", size, ((char*)pointers[i])-((char*)heapA));
}
XBT_INFO("All blocks were correctly allocated. Free every second block");
for (i = 0; i < TESTSIZE; i+=2) {
size = size_of_block(i);
mfree(heapA,pointers[i]);
}
XBT_INFO("Memset every second block to zero (yeah, they are not currently allocated :)");
for (i = 0; i < TESTSIZE; i+=2) {
size = size_of_block(i);
memset(pointers[i],0, size);
}
XBT_INFO("Re-allocate every second block");
for (i = 0; i < TESTSIZE; i+=2) {
size = size_of_block(i);
pointers[i] = mmalloc(heapA, size);
}
XBT_INFO("free all blocks (each one twice, to check that double free are correctly catched)");
for (i = 0; i < TESTSIZE; i++) {
xbt_ex_t e;
int gotit = 1;
mfree(heapA, pointers[i]);
TRY {
mfree(heapA, pointers[i]);
gotit = 0;
} CATCH(e) {
xbt_ex_free(e);
}
if (!gotit)
xbt_die("FAIL: A double-free went undetected (for size:%d)",size_of_block(i));
}
XBT_INFO("free again all blocks (to really check that double free are correctly catched)");
for (i = 0; i < TESTSIZE; i++) {
xbt_ex_t e;
int gotit = 1;
TRY {
mfree(heapA, pointers[i]);
gotit = 0;
} CATCH(e) {
xbt_ex_free(e);
}
if (!gotit)
xbt_die("FAIL: A double-free went undetected (for size:%d)",size_of_block(i));
}
XBT_INFO("Damnit, I cannot break mmalloc this time. That's SO disappointing.");
return 0;
}
