#ifndef StackBounds_h
#define StackBounds_h
#include <algorithm>
namespace WTF {
class StackBounds {
const static size_t s_defaultAvailabilityDelta = 64 * 1024;
public:
static StackBounds currentThreadStackBounds()
{
StackBounds bounds;
bounds.initialize();
bounds.checkConsistency();
return bounds;
}
void* origin() const
{
ASSERT(m_origin);
return m_origin;
}
size_t size() const
{
if (isGrowingDownward())
return static_cast<char*>(m_origin) - static_cast<char*>(m_bound);
return static_cast<char*>(m_bound) - static_cast<char*>(m_origin);
}
void* recursionLimit(size_t minAvailableDelta = s_defaultAvailabilityDelta) const
{
checkConsistency();
if (isGrowingDownward())
return static_cast<char*>(m_bound) + minAvailableDelta;
return static_cast<char*>(m_bound) - minAvailableDelta;
}
void* recursionLimit(char* startOfUserStack, size_t maxUserStack, size_t reservedZoneSize) const
{
checkConsistency();
if (maxUserStack < reservedZoneSize)
reservedZoneSize = maxUserStack;
size_t maxUserStackWithReservedZone = maxUserStack - reservedZoneSize;
if (isGrowingDownward()) {
char* endOfStackWithReservedZone = reinterpret_cast<char*>(m_bound) + reservedZoneSize;
if (startOfUserStack < endOfStackWithReservedZone)
return endOfStackWithReservedZone;
size_t availableUserStack = startOfUserStack - endOfStackWithReservedZone;
if (maxUserStackWithReservedZone > availableUserStack)
maxUserStackWithReservedZone = availableUserStack;
return startOfUserStack - maxUserStackWithReservedZone;
}
char* endOfStackWithReservedZone = reinterpret_cast<char*>(m_bound) - reservedZoneSize;
if (startOfUserStack > endOfStackWithReservedZone)
return endOfStackWithReservedZone;
size_t availableUserStack = endOfStackWithReservedZone - startOfUserStack;
if (maxUserStackWithReservedZone > availableUserStack)
maxUserStackWithReservedZone = availableUserStack;
return startOfUserStack + maxUserStackWithReservedZone;
}
bool isGrowingDownward() const
{
ASSERT(m_origin && m_bound);
#if OS(WINCE)
return m_origin > m_bound;
#else
return true;
#endif
}
private:
StackBounds()
: m_origin(0)
, m_bound(0)
{
}
WTF_EXPORT_PRIVATE void initialize();
void checkConsistency() const
{
#if !ASSERT_DISABLED
void* currentPosition = ¤tPosition;
ASSERT(m_origin != m_bound);
ASSERT(isGrowingDownward()
? (currentPosition < m_origin && currentPosition > m_bound)
: (currentPosition > m_origin && currentPosition < m_bound));
#endif
}
void* m_origin;
void* m_bound;
friend class StackStats;
};
}
using WTF::StackBounds;
#endif