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Add joining allocation table lists

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This commit is contained in:
Alex Barney 2019-04-03 18:04:04 -05:00
parent d7dd540b21
commit c89b8be887
1 changed files with 124 additions and 3 deletions
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127
src/LibHac/IO/Save/AllocationTable.cs
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@ -59,6 +59,47 @@ namespace LibHac.IO.Save
} }
} }
public void Join(int frontListBlockIndex, int backListBlockIndex)
{
int frontEntryIndex = BlockToEntryIndex(frontListBlockIndex);
int backEntryIndex = BlockToEntryIndex(backListBlockIndex);
int frontTailIndex = GetListTail(frontEntryIndex);
AllocationTableEntry frontTail = ReadEntry(frontTailIndex);
AllocationTableEntry backHead = ReadEntry(backEntryIndex);
frontTail.SetNext(backEntryIndex);
backHead.SetPrev(frontTailIndex);
WriteEntry(frontTailIndex, frontTail);
WriteEntry(backEntryIndex, backHead);
}
public int GetListLength(int blockIndex)
{
int index = blockIndex;
int totalLength = 0;
int tableSize = Header.AllocationTableBlockCount;
int nodesIterated = 0;
while (index != -1)
{
ReadEntry(index, out index, out int _, out int length);
totalLength += length;
nodesIterated++;
if (nodesIterated > tableSize)
{
throw new InvalidDataException("Cycle detected in allocation table.");
}
}
return totalLength;
}
private void ReadEntries(int entryIndex, Span<AllocationTableEntry> entries) private void ReadEntries(int entryIndex, Span<AllocationTableEntry> entries)
{ {
Debug.Assert(entries.Length >= 2); Debug.Assert(entries.Length >= 2);
@ -72,17 +113,17 @@ namespace LibHac.IO.Save
BaseStorage.Read(buffer, offset); BaseStorage.Read(buffer, offset);
} }
private void ReadEntry(int entryIndex, out AllocationTableEntry entry) private AllocationTableEntry ReadEntry(int entryIndex)
{ {
Span<byte> bytes = stackalloc byte[EntrySize]; Span<byte> bytes = stackalloc byte[EntrySize];
int offset = entryIndex * EntrySize; int offset = entryIndex * EntrySize;
BaseStorage.Read(bytes, offset); BaseStorage.Read(bytes, offset);
entry = GetEntryFromBytes(bytes); return GetEntryFromBytes(bytes);
} }
private void WriteEntry(int entryIndex, ref AllocationTableEntry entry) private void WriteEntry(int entryIndex, AllocationTableEntry entry)
{ {
Span<byte> bytes = stackalloc byte[EntrySize]; Span<byte> bytes = stackalloc byte[EntrySize];
int offset = entryIndex * EntrySize; int offset = entryIndex * EntrySize;
@ -93,6 +134,52 @@ namespace LibHac.IO.Save
BaseStorage.Write(bytes, offset); BaseStorage.Write(bytes, offset);
} }
private int GetListHead(int entryIndex)
{
int headIndex = entryIndex;
int tableSize = Header.AllocationTableBlockCount;
int nodesTraversed = 0;
AllocationTableEntry entry = ReadEntry(entryIndex);
while (!entry.IsListStart())
{
nodesTraversed++;
headIndex = entry.Prev & 0x7FFFFFFF;
entry = ReadEntry(headIndex);
if (nodesTraversed > tableSize)
{
throw new InvalidDataException("Cycle detected in allocation table.");
}
}
return headIndex;
}
private int GetListTail(int entryIndex)
{
int tailIndex = entryIndex;
int tableSize = Header.AllocationTableBlockCount;
int nodesTraversed = 0;
AllocationTableEntry entry = ReadEntry(entryIndex);
while (!entry.IsListEnd())
{
nodesTraversed++;
tailIndex = entry.Next & 0x7FFFFFFF;
entry = ReadEntry(tailIndex);
if (nodesTraversed > tableSize)
{
throw new InvalidDataException("Cycle detected in allocation table.");
}
}
return tailIndex;
}
private static ref AllocationTableEntry GetEntryFromBytes(Span<byte> entry) private static ref AllocationTableEntry GetEntryFromBytes(Span<byte> entry)
{ {
return ref MemoryMarshal.Cast<byte, AllocationTableEntry>(entry)[0]; return ref MemoryMarshal.Cast<byte, AllocationTableEntry>(entry)[0];
@ -123,10 +210,44 @@ namespace LibHac.IO.Save
return Next < 0; return Next < 0;
} }
public void MakeMultiBlockSegment()
{
Next |= unchecked((int)0x80000000);
}
public void MakeSingleBlockSegment()
{
Next &= 0x7FFFFFFF;
}
public bool IsSingleBlockSegment() public bool IsSingleBlockSegment()
{ {
return Next >= 0; return Next >= 0;
} }
public void MakeListStart()
{
Prev = int.MinValue;
}
public void MakeRangeEntry()
{
Prev |= unchecked((int)0x80000000);
}
public void SetNext(int value)
{
Debug.Assert(value >= 0);
Next = Next & unchecked((int)0x80000000) | value;
}
public void SetPrev(int value)
{
Debug.Assert(value >= 0);
Prev = value;
}
} }
public class AllocationTableHeader public class AllocationTableHeader