diff options
Diffstat (limited to 'src/gos')
-rw-r--r-- | src/gos/gos_x_heap.c | 112 |
1 files changed, 50 insertions, 62 deletions
diff --git a/src/gos/gos_x_heap.c b/src/gos/gos_x_heap.c index 7e79d1c6..813d0199 100644 --- a/src/gos/gos_x_heap.c +++ b/src/gos/gos_x_heap.c @@ -34,7 +34,6 @@ // Slot structure - user memory follows typedef struct memslot { - struct memslot *next; // The next memslot size_t sz; // Includes the size of this memslot. } memslot; @@ -48,13 +47,10 @@ #define Ptr2Slot(p) ((memslot *)(p) - 1) #define Slot2Ptr(pslot) ((pslot)+1) - static memslot * firstSlot; - static memslot * lastSlot; static memslot * freeSlots; static char heap[GFX_OS_HEAP_SIZE]; void _gosHeapInit(void) { - lastSlot = 0; gfxAddHeapBlock(heap, GFX_OS_HEAP_SIZE); } @@ -62,18 +58,12 @@ if (sz < sizeof(memslot)+sizeof(freeslot)) return; - if (lastSlot) - lastSlot->next = (memslot *)ptr; - else - firstSlot = lastSlot = freeSlots = (memslot *)ptr; - - lastSlot->next = 0; - lastSlot->sz = sz; - NextFree(lastSlot) = 0; + ((memslot *)ptr)->sz = sz; + gfxFree(Slot2Ptr((memslot *)ptr)); } void *gfxAlloc(size_t sz) { - register memslot *prev, *p, *new; + register memslot *prev, *p, *pnew; if (!sz) return 0; sz = GetSlotSize(sz); @@ -81,23 +71,22 @@ // Loop till we have a block big enough if (p->sz < sz) continue; + // Can we save some memory by splitting this block? if (p->sz >= sz + sizeof(memslot)+sizeof(freeslot)) { - new = (memslot *)((char *)p + sz); - new->next = p->next; - p->next = new; - new->sz = p->sz - sz; + pnew = (memslot *)((char *)p + sz); + pnew->sz = p->sz - sz; p->sz = sz; - if (lastSlot == p) - lastSlot = new; - NextFree(new) = NextFree(p); - NextFree(p) = new; + NextFree(pnew) = NextFree(p); + NextFree(p) = pnew; } + // Remove it from the free list if (prev) NextFree(prev) = NextFree(p); else freeSlots = NextFree(p); + // Return the result found return Slot2Ptr(p); } @@ -106,7 +95,7 @@ } void *gfxRealloc(void *ptr, size_t oldsz, size_t sz) { - register memslot *prev, *p, *new; + register memslot *prev, *p, *pfree; (void) oldsz; if (!ptr) @@ -120,19 +109,14 @@ sz = GetSlotSize(sz); // If the next slot is free (and contiguous) merge it into this one - if ((char *)p + p->sz == (char *)p->next) { - for (prev = 0, new = freeSlots; new != 0; prev = new, new = NextFree(new)) { - if (new == p->next) { - p->next = new->next; - p->sz += new->sz; - if (prev) - NextFree(prev) = NextFree(new); - else - freeSlots = NextFree(new); - if (lastSlot == new) - lastSlot = p; - break; - } + for (prev = 0, pfree = freeSlots; pfree != 0; prev = pfree, pfree = NextFree(pfree)) { + if (pfree == (memslot *)((char *)p + p->sz)) { + p->sz += pfree->sz; + if (prev) + NextFree(prev) = NextFree(pfree); + else + freeSlots = NextFree(pfree); + break; } } @@ -140,50 +124,54 @@ if (sz < p->sz) { // Can we save some memory by splitting this block? if (p->sz >= sz + sizeof(memslot)+sizeof(freeslot)) { - new = (memslot *)((char *)p + sz); - new->next = p->next; - p->next = new; - new->sz = p->sz - sz; + pfree = (memslot *)((char *)p + sz); + pfree->sz = p->sz - sz; p->sz = sz; - if (lastSlot == p) - lastSlot = new; - NextFree(new) = freeSlots; - freeSlots = new; + NextFree(pfree) = freeSlots; + freeSlots = pfree; } return Slot2Ptr(p); } // We need to do this the hard way - new = gfxAlloc(sz); - if (new) + pfree = gfxAlloc(sz); + if (pfree) return 0; - memcpy(new, ptr, p->sz - sizeof(memslot)); + memcpy(pfree, ptr, p->sz - sizeof(memslot)); gfxFree(ptr); - return new; + return pfree; } void gfxFree(void *ptr) { - register memslot *prev, *p, *new; + register memslot *prev, *p, *pfree; if (!ptr) return; p = Ptr2Slot(ptr); - // If the next slot is free (and contiguous) merge it into this one - if ((char *)p + p->sz == (char *)p->next) { - for (prev = 0, new = freeSlots; new != 0; prev = new, new = NextFree(new)) { - if (new == p->next) { - p->next = new->next; - p->sz += new->sz; - if (prev) - NextFree(prev) = NextFree(new); - else - freeSlots = NextFree(new); - if (lastSlot == new) - lastSlot = p; - break; - } + // Find a free slot that is contiguous precceding and merge it into us + for (prev = 0, pfree = freeSlots; pfree != 0; prev = pfree, pfree = NextFree(pfree)) { + if (p == (memslot *)((char *)pfree + pfree->sz)) { + pfree->sz += p->sz; + if (prev) + NextFree(prev) = NextFree(pfree); + else + freeSlots = NextFree(pfree); + p = pfree; + break; + } + } + + // Find a free slot that is contiguous after and merge it into this one + for (prev = 0, pfree = freeSlots; pfree != 0; prev = pfree, pfree = NextFree(pfree)) { + if (pfree == (memslot *)((char *)p + p->sz)) { + p->sz += pfree->sz; + if (prev) + NextFree(prev) = NextFree(pfree); + else + freeSlots = NextFree(pfree); + break; } } |