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#include "Heap.class.h"
#ifdef THIS_IS_MELON_KERNEL
#include <MemoryManager/PageDirectory.class.h>
#endif
#ifdef THIS_IS_MELON_KERNEL
Heap::Heap() : m_mutex(MUTEX_FALSE) {
#else
Heap::Heap() : m_mutex(MUTEX_FALSE), m_process(Process::get()) {
#endif
m_usable = false;
m_index.data = 0;
m_index.size = 0;
}
Heap::~Heap() {
//TODO (optionnal) : free pages.
}
#ifdef THIS_IS_MELON_KERNEL
void Heap::create(u32int start, u32int size, u32int idxsize, PageDirectory* pagedir, bool user, bool rw) {
#else
void Heap::create(u32int start, u32int size, u32int idxsize) {
#endif
if (m_usable) return;
if (start & 0x0FFF) start = (start & 0xFFFFF000) + 0x1000;
if (size & 0x0FFF) size = (size & 0xFFFFF000) + 0x1000;
m_start = start + idxsize; //m_start is start of real data, start is start of index.
m_end = start + size;
#ifdef THIS_IS_MELON_KERNEL
m_pagedir = pagedir;
m_user = user;
m_rw = rw;
//Allocate frames for heap
for (u32int i = start ; i < m_end; i += 0x1000) {
m_pagedir->allocFrame(i, m_user, m_rw);
}
m_pagedir->switchTo();
#else
m_process.allocPages(start, m_end);
#endif
m_index.data = (heap_header_t **)start; //Set index start. start == start of all heap
m_index.size = 0;
heap_header_t *hole = (heap_header_t*) m_start; //m_start == start of data
hole->size = (m_end - m_start);
hole->magic = HEAP_MAGIC;
hole->is_hole = true;
heap_footer_t *hole_footer = (heap_footer_t*) (m_end - sizeof(heap_footer_t));
hole_footer->header = hole;
hole_footer->magic = HEAP_MAGIC;
insertIntoIndex(hole);
m_usable = true;
m_free = (m_end - m_start);
m_mutex.unlock();
}
void Heap::expand(u32int quantity) {
if (quantity & 0x00000FFF)
quantity = (quantity & 0xFFFFF000) + 0x1000;
u32int newEnd = m_end + quantity;
#ifdef THIS_IS_MELON_KERNEL
for (u32int i = m_end ; i < newEnd; i += 0x1000) {
m_pagedir->allocFrame(i, m_user, m_rw);
}
#else
m_process.allocPages(m_end, newEnd);
#endif
heap_footer_t *last_footer = (heap_footer_t*) (m_end - sizeof(heap_footer_t));
heap_header_t *last_header = last_footer->header;
if (last_header->is_hole) { //Last block of heap is a hole, update its size
removeFromIndex(last_header);
last_header->size += quantity;
last_footer = (heap_footer_t*) (newEnd - sizeof(heap_footer_t));
last_footer->magic = HEAP_MAGIC;
last_footer->header = last_header;
insertIntoIndex(last_header);
} else { //Last block is not a hole. Just add a new hole at the end
last_header = (heap_header_t*)m_end;
last_footer = (heap_footer_t*) (newEnd - sizeof(heap_footer_t));
last_header->is_hole = true;
last_header->magic = HEAP_MAGIC;
last_header->size = quantity;
last_footer->magic = HEAP_MAGIC;
last_footer->header = last_header;
insertIntoIndex(last_header);
}
m_end = newEnd;
m_free += quantity;
}
void Heap::contract() { //Automatically work out how much we can contract
heap_footer_t *last_footer = (heap_footer_t*) (m_end - sizeof(heap_footer_t));
heap_header_t *last_header = last_footer->header;
if (last_header->is_hole == false) return; //We need a hole at end of heap
u32int quantity = 0;
while ((m_end - m_start) - quantity > HEAP_MIN_SIZE and
(last_header->size - quantity) > 0x1000) //Always keep at least 0x1000 free at end
quantity += 0x1000;
if (quantity == 0) return;
u32int newEnd = m_end - quantity;
m_free -= quantity;
removeFromIndex(last_header);
last_header->size -= quantity;
last_footer = (heap_footer_t*)((u32int)last_footer - quantity);
last_footer->magic = HEAP_MAGIC;
last_footer->header = last_header;
insertIntoIndex(last_header);
#ifdef THIS_IS_MELON_KERNEL
for (u32int i = newEnd; i < m_end; i += 0x1000) {
m_pagedir->freeFrame(i);
}
#else
m_process.freePages(newEnd, m_end);
#endif
m_end = newEnd;
}
void *Heap::alloc(size_t sz, bool no_expand) {
m_mutex.waitLock();
u32int newsize = sz + sizeof(heap_header_t) + sizeof(heap_footer_t);
u32int iterator = 0;
while (iterator < m_index.size) {
if (m_index.data[iterator]->size >= newsize) break;
iterator++;
}
if (iterator == m_index.size) { //No hole is big enough
if (no_expand) {
m_mutex.unlock();
return 0;
}
expand((sz & 0xFFFFF000) + 0x1000);
m_mutex.unlock();
return alloc(sz, true); //Recurse call
}
heap_header_t *loc = m_index.data[iterator];
heap_footer_t *footer = (heap_footer_t*)((u32int)loc + loc->size - sizeof(heap_footer_t));
loc->is_hole = false; //Update current header
removeFromIndex(loc);
//Here we create a new hole after currently allocated block, but only if we have enough space. If we don't, we simply allocate a bigger block so that we don't loose space
if (loc->size > (newsize + sizeof(heap_header_t) + sizeof(heap_footer_t))) {
loc->size = newsize; //Update header for return block
heap_footer_t *newfooter = (heap_footer_t*)((u32int)loc + newsize - sizeof(heap_footer_t)); //Write footer for return block
newfooter->header = loc;
newfooter->magic = HEAP_MAGIC;
heap_header_t *nextloc = (heap_header_t*)((u32int)loc + newsize); //Write header for new hole
nextloc->is_hole = true;
nextloc->magic = HEAP_MAGIC;
nextloc->size = ((u32int)footer - (u32int)nextloc + sizeof(heap_footer_t));
footer->header = nextloc; //Write footer for new hole
footer->magic = HEAP_MAGIC;
insertIntoIndex(nextloc);
}
m_free -= loc->size;
m_mutex.unlock();
return (void*)((u32int)loc + sizeof(heap_header_t));
}
void Heap::free(void *ptr) {
if (ptr == 0) return;
heap_header_t *header = (heap_header_t*) ((u32int)ptr - sizeof(heap_header_t));
heap_footer_t *footer = (heap_footer_t*)((u32int)header + header->size - sizeof(heap_footer_t));
if (header->magic != HEAP_MAGIC or footer->magic != HEAP_MAGIC) return;
m_mutex.waitLock();
m_free += header->size;
//Unify left
heap_footer_t *prev_footer = (heap_footer_t*)((u32int)header - sizeof(heap_footer_t));
if (prev_footer->magic == HEAP_MAGIC && prev_footer->header->is_hole) {
header = prev_footer->header;
removeFromIndex(header);
footer->header = header;
header->size = ((u32int)footer - (u32int)header + sizeof(heap_footer_t));
}
//Unify right
heap_header_t *next_header = (heap_header_t*)((u32int)footer + sizeof(heap_footer_t));
if (next_header->magic == HEAP_MAGIC && next_header->is_hole) {
removeFromIndex(next_header);
footer = (heap_footer_t*)((u32int)footer + next_header->size);
footer->header = header;
header->size = ((u32int)footer - (u32int)header + sizeof(heap_footer_t));
}
header->is_hole = true;
insertIntoIndex(header);
if ((u32int)footer == (m_end - sizeof(heap_footer_t)) and
header->size >= 0x2000 and (m_end - m_start > HEAP_MIN_SIZE)) {
contract();
}
m_mutex.unlock();
}
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