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#include <limits.h>
#include "tracebuffer.H"
TracePage* TracePage::setNext(TracePage* new_next)
{
return __sync_val_compare_and_swap(&this->next, NULL, new_next);
}
traceEntry* TracePage::claimEntry(size_t size)
{
// this->size will eventually wrap and it will suddenly look like there
// is free space?
size_t position = __sync_fetch_and_add(&this->size, size);
if (position > (PAGE_SIZE - sizeof(TracePage)))
{
return NULL;
}
else
{
return (traceEntry*)&((uint8_t*)this)[sizeof(TracePage) + position];
}
}
traceEntry* TraceBuffer::claimEntry(size_t size)
{
traceEntry* result = NULL;
TracePage* page = last;
while (result == NULL)
{
result = page->claimEntry(size);
if (NULL == result)
{
if (NULL != page->getNext())
{
__sync_bool_compare_and_swap(&this->last,
page, page->getNext());
page = page->getNext();
}
else
{
TracePage* new_page = new (malloc(PAGE_SIZE)) TracePage();
TracePage* prev = page;
while(prev != NULL)
{
prev = prev->setNext(new_page);
}
}
}
}
return result;
}
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