// create a test sequence which never uses more than max_used_memory
// and allocates a total of max_used_memory*allocation_factor
SEQLIST *generate_sequence(int max_used_memory, int allocation_factor) {
int used_memory = 0;
int total_allocated = 0;
int next_block_size = 0;
int allocated_blocks = 0;
int actual_max_used_memory = 0;
SEQLIST *test_sequence = (SEQLIST *) 0;
SEQLIST *tail_sequence = (SEQLIST *) 0;
SEQLIST *tofree = (SEQLIST *) 0;
unsigned char *new_block_ref;
while (total_allocated < allocation_factor * max_used_memory) {
next_block_size = random_block_size(max_used_memory);
// first see if we need to free anything in order to
// accommodate the new allocation
while (used_memory + next_block_size > max_used_memory) {
// randomly pick a block to free
SEQLIST *tofree =
find_nth_allocated_block(test_sequence, random_int(allocated_blocks));
// add the free
tail_sequence = seq_set_next_free(tofree, tail_sequence);
// reclaim the memory
used_memory -= seq_size(tofree);
allocated_blocks--;
// mark the old block as something that has been freed
seq_free(tofree);
}
// allocate a reference buffer for the new block
new_block_ref = allocate_and_fill(next_block_size);
// now allocate that block
if (seq_null(test_sequence)) {
// special case for first allocation
test_sequence = seq_add_front(next_block_size, new_block_ref, (SEQLIST *) 0);
tail_sequence = test_sequence;
}
else {
// typical case we add at the end
tail_sequence =
seq_set_next_allocate(next_block_size, new_block_ref, tail_sequence);
}
// debug
//seq_print(tail_sequence); // just prints the new one
total_allocated += next_block_size;
used_memory += next_block_size;
if (used_memory > actual_max_used_memory)
actual_max_used_memory = used_memory;
allocated_blocks++;
}
// just so can manually see this is doing something sensible
printf("Actual maximum memory usage %d (%f)\n", actual_max_used_memory,
((double) actual_max_used_memory / (double) max_used_memory));
return test_sequence;
}
void vector<T>::fill_and_initialize(size_type n, const T& x) {
iterator result = allocate_and_fill(n, x);
_start = result;
_end = result + n;
_capacity = _capacity + n;
}
