project64/Source/Common/MemoryManagement.cpp

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#include "stdafx.h"
#ifdef _WIN32
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#include <windows.h>
#else
#include <sys/mman.h>
#endif
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#include "MemoryManagement.h"
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static bool TranslateFromMemProtect(MEM_PROTECTION memProtection, int & OsMemProtection)
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{
#ifdef _WIN32
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switch (memProtection)
{
case MEM_NOACCESS: OsMemProtection = PAGE_NOACCESS; break;
case MEM_READONLY: OsMemProtection = PAGE_READONLY; break;
case MEM_READWRITE: OsMemProtection = PAGE_READWRITE; break;
case MEM_EXECUTE_READWRITE: OsMemProtection = PAGE_EXECUTE_READWRITE; break;
default:
return false;
}
#else
switch (memProtection)
{
case MEM_NOACCESS: OsMemProtection = PROT_NONE; break;
case MEM_READONLY: OsMemProtection = PROT_READ; break;
case MEM_READWRITE: OsMemProtection = PROT_READ | PROT_WRITE; break;
case MEM_EXECUTE_READWRITE: OsMemProtection = PROT_READ | PROT_WRITE | PROT_EXEC; break;
default:
return false;
}
#endif
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return true;
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}
#ifdef _WIN32
static bool TranslateToMemProtect(int OsMemProtection, MEM_PROTECTION & memProtection)
{
switch (OsMemProtection)
{
case PAGE_NOACCESS: memProtection = MEM_NOACCESS; break;
case PAGE_READONLY: memProtection = MEM_READONLY; break;
case PAGE_READWRITE: memProtection = MEM_READWRITE; break;
case PAGE_EXECUTE_READWRITE: memProtection = MEM_EXECUTE_READWRITE; break;
default:
return false;
}
return true;
}
#endif
void* AllocateAddressSpace(size_t size, void * base_address)
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{
#ifdef _WIN32
return VirtualAlloc(base_address, size, MEM_RESERVE | MEM_TOP_DOWN, PAGE_NOACCESS);
#else
void * ptr = mmap((void*)0, size, PROT_NONE, MAP_PRIVATE | MAP_ANON, -1, 0);
if (ptr == MAP_FAILED)
{
return NULL;
}
msync(ptr, size, MS_SYNC | MS_INVALIDATE);
return ptr;
#endif
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}
bool FreeAddressSpace(void* addr, size_t size)
{
#ifdef _WIN32
size = 0; //unused
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return VirtualFree(addr, 0, MEM_RELEASE) != 0;
#else
msync(addr, size, MS_SYNC);
munmap(addr, size);
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return true;
#endif
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}
void* CommitMemory(void* addr, size_t size, MEM_PROTECTION memProtection)
{
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int OsMemProtection;
if (!TranslateFromMemProtect(memProtection, OsMemProtection))
{
return NULL;
}
#ifdef _WIN32
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return VirtualAlloc(addr, size, MEM_COMMIT, OsMemProtection);
#else
void * ptr = mmap(addr, size, OsMemProtection, MAP_FIXED | MAP_SHARED | MAP_ANON, -1, 0);
msync(addr, size, MS_SYNC | MS_INVALIDATE);
return ptr;
#endif
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}
bool DecommitMemory(void* addr, size_t size)
{
#ifdef _WIN32
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return VirtualFree((void*)addr, size, MEM_DECOMMIT) != 0;
#else
// instead of unmapping the address, we're just gonna trick
// the TLB to mark this as a new mapped area which, due to
// demand paging, will not be committed until used.
mmap(addr, size, PROT_NONE, MAP_FIXED | MAP_PRIVATE | MAP_ANON, -1, 0);
msync(addr, size, MS_SYNC | MS_INVALIDATE);
return true;
#endif
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}
bool ProtectMemory(void* addr, size_t size, MEM_PROTECTION memProtection, MEM_PROTECTION * OldProtect)
{
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int OsMemProtection;
if (!TranslateFromMemProtect(memProtection, OsMemProtection))
{
return false;
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}
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#ifdef _WIN32
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DWORD OldOsProtect;
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BOOL res = VirtualProtect(addr, size, OsMemProtection, &OldOsProtect);
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if (OldProtect != NULL)
{
if (!TranslateToMemProtect(OldOsProtect, *OldProtect))
{
return NULL;
}
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}
return res != 0;
#else
return mprotect(addr, size, OsMemProtection) == 0;
#endif
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}