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#include "global.h"
extern void *gHeapStart;
extern u32 gHeapSize;
#define MALLOC_SYSTEM_ID 0xA3A3
struct MemBlock {
u16 flag;
u16 magic;
u32 size;
struct MemBlock *prev;
struct MemBlock *next;
};
void PutMemBlockHeader(void *block, struct MemBlock *prev, struct MemBlock *next, u32 size)
{
struct MemBlock *header = (struct MemBlock *)block;
header->flag = 0;
header->magic = MALLOC_SYSTEM_ID;
header->size = size;
header->prev = prev;
header->next = next;
}
void PutFirstMemBlockHeader(void *block, u32 size)
{
PutMemBlockHeader(block, (struct MemBlock *)block, (struct MemBlock *)block, size - 16);
}
void *AllocInternal(struct MemBlock *pos, u32 size)
{
struct MemBlock *head = pos;
struct MemBlock *splitBlock;
u32 foundBlockSize;
if (size & 3)
size = 4 * ((size / 4) + 1);
for (;;) {
// Loop through the blocks looking for unused block that's big enough.
if (!pos->flag) {
foundBlockSize = pos->size;
if (foundBlockSize >= size) {
if (foundBlockSize - size <= 31) {
// The block isn't much bigger than the requested size,
// so just use it.
pos->flag = TRUE;
} else {
// The block is significantly bigger than the requested
// size, so split the rest into a separate block.
foundBlockSize -= sizeof(struct MemBlock);
foundBlockSize -= size;
splitBlock = (struct MemBlock *)((u8 *)(&pos[1]) + size);
pos->flag = TRUE;
pos->size = size;
PutMemBlockHeader(splitBlock, pos, pos->next, foundBlockSize);
pos->next = splitBlock;
if (splitBlock->next != head)
splitBlock->next->prev = splitBlock;
return &pos[1];
}
}
}
if (pos->next == head)
return NULL;
pos = pos->next;
}
}
void FreeInternal(void *heapStart, void *pointer)
{
if (pointer) {
struct MemBlock *head = (struct MemBlock *)heapStart;
struct MemBlock *block = (struct MemBlock *)((u8 *)pointer - sizeof(struct MemBlock));
block->flag = FALSE;
// If the freed block isn't the last one, merge with the next block
// if it's not in use.
if (block->next != head) {
if (!block->next->flag) {
block->size += sizeof(struct MemBlock) + block->next->size;
block->next->magic = 0;
block->next = block->next->next;
if (block->next != head)
block->next->prev = block;
}
}
// If the freed block isn't the first one, merge with the previous block
// if it's not in use.
if (block != head) {
if (!block->prev->flag) {
block->prev->next = block->next;
if (block->next != head)
block->next->prev = block->prev;
block->magic = 0;
block->prev->size += sizeof(struct MemBlock) + block->size;
}
}
}
}
void *AllocZeroedInternal(void *heapStart, u32 size)
{
void *mem = AllocInternal((struct MemBlock *)heapStart, size);
if (mem != NULL) {
u32 zero;
u32 sizeInWords;
if (size & 3)
size = 4 * ((size / 4) + 1);
zero = 0;
sizeInWords = (size << 9) >> 11;
CpuSet(&zero, mem, CPU_SET_32BIT | CPU_SET_SRC_FIX | sizeInWords);
}
return mem;
}
bool32 CheckMemBlockInternal(void *heapStart, void *pointer)
{
struct MemBlock *head = (struct MemBlock *)heapStart;
struct MemBlock *block = (struct MemBlock *)((u8 *)pointer - sizeof(struct MemBlock));
if (block->magic != MALLOC_SYSTEM_ID)
return FALSE;
if (block->next->magic != MALLOC_SYSTEM_ID)
return FALSE;
if (block->next != head && block->next->prev != block)
return FALSE;
if (block->prev->magic != MALLOC_SYSTEM_ID)
return FALSE;
if (block->prev != head && block->prev->next != block)
return FALSE;
if (block->next != head && block->next != (struct MemBlock *)((u8 *)(&block[1]) + block->size))
return FALSE;
return TRUE;
}
void InitHeap(void *heapStart, u32 heapSize)
{
gHeapStart = heapStart;
gHeapSize = heapSize;
PutFirstMemBlockHeader(heapStart, heapSize);
}
void *Alloc(u32 size)
{
AllocInternal(gHeapStart, size);
}
void *AllocZeroed(u32 size)
{
AllocZeroedInternal(gHeapStart, size);
}
void Free(void *pointer)
{
FreeInternal(gHeapStart, pointer);
}
bool32 CheckMemBlock(void *pointer)
{
return CheckMemBlockInternal(gHeapStart, pointer);
}
bool32 CheckHeap()
{
struct MemBlock *pos = (struct MemBlock *)gHeapStart;
do {
if (!CheckMemBlockInternal(gHeapStart, &pos[1]))
return FALSE;
pos = pos->next;
} while (pos != (struct MemBlock *)gHeapStart);
return TRUE;
}
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