/// <summary>
/// Constructor.
/// </summary>
/// <param name="indexFile"></param>
/// <param name="dataFile"></param>
protected void Initialize(String indexFile, String dataFile)
{
logger.Trace("Cache index file: {0}", indexFile);
logger.Trace("Cache data file: {0}", dataFile);
// Open cache files if BOTH index and data files exist
if (File.Exists(indexFile) && File.Exists(dataFile))
{
try
{
logger.Info("Cache files found, attempting to load.");
// Open cache files
indexStream = new StreamEx(indexFile);
dataStream = new StreamEx(dataFile);
// Load index file
string magicNumber = new String(Encoding.ASCII.GetChars(indexStream.ReadBytes(0x10)));
if (magicNumber.Equals(MagicNumber))
{
// Calculate the entry count
long entryCount = (indexStream.Length - MagicNumber.Length) / IndexAlignment;
// Load Data
for (int i = 0; i < entryCount; i++)
{
// Load Address and length
long address = indexStream.ReadInt64();
long length = indexStream.ReadInt64();
// Entry is valid only if address is greater or equal than 0
if (address >= 0)
{
// Read Name
string name =
new String(Encoding.UTF8.GetChars(indexStream.ReadBytes(IndexAlignment - 0x10)));
name = name.TrimEnd('\0');
// Add Entry
CacheEntry entry = new CacheEntry
{
Address = address,
Length = length,
MetadataAddress = i * IndexAlignment + MagicNumber.Length,
Name = name
};
entriesMap.Add(entry.Name, entry.Address);
entries.Add(entry.Address, entry);
}
else
{
// Add the unused entry to the holes
indexHoles.Enqueue(i * IndexAlignment + MagicNumber.Length);
}
}
// Scan for data holes
//var sortedEntries = entries.Values.OrderBy(t => t.Address).ToArray();
CacheEntry[] sortedEntries = entries.Values.ToArray(); // <-- this should be sorted correctly
for (int i = 0; i < entries.Count - 1; i++)
{
long lastEntryEnd = Align(sortedEntries[i].EndAddress, DataAlignment);
long nextEntryStart = sortedEntries[i + 1].Address;
long holeSize = nextEntryStart - lastEntryEnd;
// Positive hole size means a data hole, negative means corrupted data
if (holeSize > 0)
{
dataHoles.Add(lastEntryEnd, holeSize);
}
else if (holeSize < 0)
{
throw new InvalidDataException("Negative hole (overlapping data) detected.");
}
}
}
else
{
throw new InvalidDataException("Invalid magic number!");
}
}
catch (Exception x)
{
logger.Warn("Cache file corrupted: [{0}] {1}", x.GetType().FullName, x.Message);
indexStream.Dispose();
dataStream.Dispose();
indexStream = null;
dataStream = null;
}
}
else
{
logger.Info("Cache index or data file not found, proceeding to creating empty cache.");
}
if (indexStream == null && dataStream == null)
{
// Overwrite BOTH index and data files if one of them is missing
// This is also the fallback route if cache files are corrupted
indexStream = new StreamEx(indexFile, FileMode.Create);
indexStream.WriteBytes(Encoding.ASCII.GetBytes(MagicNumber));
dataStream = new StreamEx(dataFile, FileMode.Create);
}
}