/// <exception cref="System.IO.IOException"></exception>
internal virtual ObjectLoader Load(WindowCursor curs, long pos)
{
try
{
byte[] ib = curs.tempId;
PackFile.Delta delta = null;
byte[] data = null;
int type = Constants.OBJ_BAD;
bool cached = false;
for (; ;)
{
ReadFully(pos, ib, 0, 20, curs);
int c = ib[0] & unchecked ((int)(0xff));
int typeCode = (c >> 4) & 7;
long sz = c & 15;
int shift = 4;
int p = 1;
while ((c & unchecked ((int)(0x80))) != 0)
{
c = ib[p++] & unchecked ((int)(0xff));
sz += (c & unchecked ((int)(0x7f))) << shift;
shift += 7;
}
switch (typeCode)
{
case Constants.OBJ_COMMIT:
case Constants.OBJ_TREE:
case Constants.OBJ_BLOB:
case Constants.OBJ_TAG:
{
if (sz < curs.GetStreamFileThreshold())
{
data = Decompress(pos + p, (int)sz, curs);
}
if (delta != null)
{
type = typeCode;
goto SEARCH_break;
}
if (data != null)
{
return(new ObjectLoader.SmallObject(typeCode, data));
}
else
{
return(new LargePackedWholeObject(typeCode, sz, pos, p, this, curs.db));
}
goto case Constants.OBJ_OFS_DELTA;
}
case Constants.OBJ_OFS_DELTA:
{
c = ib[p++] & unchecked ((int)(0xff));
long @base = c & 127;
while ((c & 128) != 0)
{
@base += 1;
c = ib[p++] & unchecked ((int)(0xff));
@base <<= 7;
@base += (c & 127);
}
@base = pos - @base;
delta = new PackFile.Delta(delta, pos, (int)sz, p, @base);
if (sz != delta.deltaSize)
{
goto SEARCH_break;
}
DeltaBaseCache.Entry e = DeltaBaseCache.Get(this, @base);
if (e != null)
{
type = e.type;
data = e.data;
cached = true;
goto SEARCH_break;
}
pos = @base;
goto SEARCH_continue;
}
case Constants.OBJ_REF_DELTA:
{
ReadFully(pos + p, ib, 0, 20, curs);
long @base = FindDeltaBase(ObjectId.FromRaw(ib));
delta = new PackFile.Delta(delta, pos, (int)sz, p + 20, @base);
if (sz != delta.deltaSize)
{
goto SEARCH_break;
}
DeltaBaseCache.Entry e = DeltaBaseCache.Get(this, @base);
if (e != null)
{
type = e.type;
data = e.data;
cached = true;
goto SEARCH_break;
}
pos = @base;
goto SEARCH_continue;
}
default:
{
throw new IOException(MessageFormat.Format(JGitText.Get().unknownObjectType, typeCode
));
}
}
SEARCH_continue :;
}
SEARCH_break :;
// At this point there is at least one delta to apply to data.
// (Whole objects with no deltas to apply return early above.)
if (data == null)
{
return(delta.Large(this, curs));
}
do
{
// Cache only the base immediately before desired object.
if (cached)
{
cached = false;
}
else
{
if (delta.next == null)
{
DeltaBaseCache.Store(this, delta.basePos, data, type);
}
}
pos = delta.deltaPos;
byte[] cmds = Decompress(pos + delta.hdrLen, delta.deltaSize, curs);
if (cmds == null)
{
data = null;
// Discard base in case of OutOfMemoryError
return(delta.Large(this, curs));
}
long sz = BinaryDelta.GetResultSize(cmds);
if (int.MaxValue <= sz)
{
return(delta.Large(this, curs));
}
byte[] result;
try
{
result = new byte[(int)sz];
}
catch (OutOfMemoryException)
{
data = null;
// Discard base in case of OutOfMemoryError
return(delta.Large(this, curs));
}
BinaryDelta.Apply(data, cmds, result);
data = result;
delta = delta.next;
}while (delta != null);
return(new ObjectLoader.SmallObject(type, data));
}
catch (SharpZipBaseException dfe)
{
CorruptObjectException coe = new CorruptObjectException(MessageFormat.Format(JGitText
.Get().objectAtHasBadZlibStream, pos, GetPackFile()));
Sharpen.Extensions.InitCause(coe, dfe);
throw coe;
}
}
