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//===- MemoryArea.cpp -----------------------------------------------------===//
//
// The MCLinker Project
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include <mcld/Support/RegionFactory.h>
#include <mcld/Support/MemoryArea.h>
#include <mcld/Support/MemoryRegion.h>
#include <mcld/Support/FileHandle.h>
#include <mcld/Support/MsgHandling.h>
using namespace mcld;
//===--------------------------------------------------------------------===//
// MemoryArea
// MemoryArea - special constructor
// This constructor is used for *SPECIAL* situation. I'm sorry I can not
// reveal what is the special situation.
MemoryArea::MemoryArea(RegionFactory& pRegionFactory, Space& pUniverse)
: m_RegionFactory(pRegionFactory), m_pFileHandle(NULL) {
m_SpaceList.push_back(&pUniverse);
}
MemoryArea::MemoryArea(RegionFactory& pRegionFactory, FileHandle& pFileHandle)
: m_RegionFactory(pRegionFactory), m_pFileHandle(&pFileHandle) {
}
MemoryArea::~MemoryArea()
{
}
// The layout of MemorySpace in the virtual memory space
//
// | : page boundary
// [,]: MemoryRegion
// - : fillment
// = : data
//
// |---[=|====|====|==]--|
// ^ ^ ^ ^
// | | | |
// | r_start +r_len |
// space.data +space.size
//
// space.file_offset is the offset of the mapped file segment from the start of
// the file. if the MemorySpace's type is ALLOCATED_ARRAY, the distances of
// (space.data, r_start) and (r_len, space.size) are zero.
//
MemoryRegion* MemoryArea::request(size_t pOffset, size_t pLength)
{
Space* space = find(pOffset, pLength);
if (NULL == space) {
// not found
if (NULL == m_pFileHandle) {
// if m_pFileHandle is NULL, clients delegate us an universal Space and
// we never remove it. In that way, space can not be NULL.
unreachable(diag::err_out_of_range_region);
}
space = Space::createSpace(*m_pFileHandle, pOffset, pLength);
m_SpaceList.push_back(space);
}
// adjust r_start
off_t distance = pOffset - space->start();
void* r_start = space->memory() + distance;
// now, we have a legal space to hold the new MemoryRegion
return m_RegionFactory.produce(*space, r_start, pLength);
}
// release - release a MemoryRegion
void MemoryArea::release(MemoryRegion* pRegion)
{
if (NULL == pRegion)
return;
Space *space = pRegion->parent();
m_RegionFactory.destruct(pRegion);
if (0 == space->numOfRegions()) {
if (NULL != m_pFileHandle) {
// if m_pFileHandle is NULL, clients delegate us an universal Space and
// we never remove it. Otherwise, we have to synchronize and release
// Space.
if (m_pFileHandle->isWritable()) {
// synchronize writable space before we release it.
Space::syncSpace(space, *m_pFileHandle);
}
Space::releaseSpace(space, *m_pFileHandle);
}
m_SpaceList.erase(space);
}
}
// clear - release all MemoryRegions
void MemoryArea::clear()
{
if (NULL == m_pFileHandle)
return;
if (m_pFileHandle->isWritable()) {
SpaceList::iterator space, sEnd = m_SpaceList.end();
for (space = m_SpaceList.begin(); space != sEnd; ++space) {
Space::syncSpace(space, *m_pFileHandle);
Space::releaseSpace(space, *m_pFileHandle);
}
}
else {
SpaceList::iterator space, sEnd = m_SpaceList.end();
for (space = m_SpaceList.begin(); space != sEnd; ++space)
Space::releaseSpace(space, *m_pFileHandle);
}
m_SpaceList.clear();
}
//===--------------------------------------------------------------------===//
// SpaceList methods
Space* MemoryArea::find(size_t pOffset, size_t pLength)
{
SpaceList::iterator sIter, sEnd = m_SpaceList.end();
for (sIter = m_SpaceList.begin(); sIter!=sEnd; ++sIter) {
if (sIter->start() <= pOffset &&
(pOffset+pLength) <= (sIter->start()+sIter->size()) ) {
// within
return sIter;
}
}
return NULL;
}
const Space* MemoryArea::find(size_t pOffset, size_t pLength) const
{
SpaceList::const_iterator sIter, sEnd = m_SpaceList.end();
for (sIter = m_SpaceList.begin(); sIter!=sEnd; ++sIter) {
if (sIter->start() <= pOffset &&
(pOffset+pLength) <= (sIter->start()+sIter->size()) ) {
// within
return sIter;
}
}
return NULL;
}