usbloadergx/source/memory/mem2alloc.cpp

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#include "mem2alloc.h"
#include <ogc/system.h>
#include <algorithm>
#include <string.h>
class LockMutex
{
mutex_t &m_mutex;
public:
LockMutex(mutex_t &m) : m_mutex(m) { LWP_MutexLock(m_mutex); }
~LockMutex(void) { LWP_MutexUnlock(m_mutex); }
};
void CMEM2Alloc::init(unsigned int size)
{
m_baseAddress = (SBlock *)(((u32)SYS_GetArena2Lo() + 31) & ~31);
m_endAddress = (SBlock *)((char *)m_baseAddress + std::min(size * 0x100000, SYS_GetArena2Size() & ~31));
if (m_endAddress > (SBlock *)0x93000000) // See loader/disc.c
m_endAddress = (SBlock *)0x93000000;
SYS_SetArena2Lo(m_endAddress);
LWP_MutexInit(&m_mutex, 0);
}
void CMEM2Alloc::init(void *addr, void *end)
{
m_baseAddress = (SBlock *)(((u32)addr + 31) & ~31);
m_endAddress = (SBlock *)((u32)end & ~31);
LWP_MutexInit(&m_mutex, 0);
}
void CMEM2Alloc::cleanup(void)
{
LWP_MutexDestroy(m_mutex);
m_mutex = 0;
m_first = 0;
// // Try to release the range we took through SYS functions
// if (SYS_GetArena2Lo() == m_endAdress)
// SYS_SetArena2Lo(m_baseAddress);
m_baseAddress = 0;
m_endAddress = 0;
}
void CMEM2Alloc::clear(void)
{
m_first = 0;
memset(m_baseAddress, 0, (u8 *)m_endAddress - (u8 *)m_endAddress);
}
unsigned int CMEM2Alloc::usableSize(void *p)
{
return p == 0 ? 0 : ((SBlock *)p - 1)->s * sizeof (SBlock);
}
void *CMEM2Alloc::allocate(unsigned int s)
{
if (s == 0)
s = 1;
//
LockMutex lock(m_mutex);
//
s = (s - 1) / sizeof (SBlock) + 1;
// First block
if (m_first == 0)
{
if (m_baseAddress + s + 1 >= m_endAddress)
return 0;
m_first = m_baseAddress;
m_first->next = 0;
m_first->prev = 0;
m_first->s = s;
m_first->f = false;
return (void *)(m_first + 1);
}
// Search for a free block
SBlock *i;
SBlock *j;
for (i = m_first; i != 0; i = i->next)
{
if (i->f && i->s >= s)
break;
j = i;
}
// Create a new block
if (i == 0)
{
i = j + j->s + 1;
if (i + s + 1 >= m_endAddress)
return 0;
j->next = i;
i->prev = j;
i->next = 0;
i->s = s;
i->f = false;
return (void *)(i + 1);
}
// Reuse a free block
i->f = false;
// Split it
if (i->s > s + 1)
{
j = i + s + 1;
j->f = true;
j->s = i->s - s - 1;
i->s = s;
j->next = i->next;
j->prev = i;
i->next = j;
if (j->next != 0)
j->next->prev = j;
}
return (void *)(i + 1);
}
void CMEM2Alloc::release(void *p)
{
if (p == 0)
return;
LockMutex lock(m_mutex);
SBlock *i = (SBlock *)p - 1;
i->f = true;
// Merge with previous block
if (i->prev != 0 && i->prev->f)
{
i = i->prev;
i->s += i->next->s + 1;
i->next = i->next->next;
if (i->next != 0)
i->next->prev = i;
}
// Merge with next block
if (i->next != 0 && i->next->f)
{
i->s += i->next->s + 1;
i->next = i->next->next;
if (i->next != 0)
i->next->prev = i;
}
}
void *CMEM2Alloc::reallocate(void *p, unsigned int s)
{
SBlock *i;
SBlock *j;
void *n;
if (s == 0)
s = 1;
if (p == 0)
return allocate(s);
i = (SBlock *)p - 1;
s = (s - 1) / sizeof (SBlock) + 1;
{
LockMutex lock(m_mutex);
// Last block
if (i->next == 0 && i + s + 1 < m_endAddress)
{
i->s = s;
return p;
}
// Size <= current size + next block
if (i->s < s && i->next->f && i->s + i->next->s + 1 >= s)
{
// Merge
i->s += i->next->s + 1;
i->next = i->next->next;
if (i->next != 0)
i->next->prev = i;
}
// Size <= current size
if (i->s >= s)
{
// Split
if (i->s > s + 1)
{
j = i + s + 1;
j->f = true;
j->s = i->s - s - 1;
i->s = s;
j->next = i->next;
j->prev = i;
i->next = j;
if (j->next != 0)
j->next->prev = j;
}
return p;
}
}
// Size > current size
n = allocate(s * sizeof (SBlock));
if (n == 0)
return 0;
memcpy(n, p, i->s * sizeof (SBlock));
release(p);
return n;
}