//Return the offset for the nth member from an Array or Object type
int GetNthOffset(int index)
{
int offset;
byte head = TypeCode;
if (head == 0x13 || head == 0x14)
{
// compact Array or Object
offset = GetNthOffsetFromCompact(index);
}
else if (head == 0x01 || head == 0x0a)
{
// special case: empty Array or empty Object
throw new IndexOutOfRangeException();
}
else
{
long n;
int offsetsize = ObjectArrayUtil.GetOffsetSize(head);
long end = NumberUtil.ToLong(vpack, start + 1, offsetsize);
int dataOffset = FindDataOffset();
if (head <= 0x05)
{
// array with no offset table or length
VPackSlice first = new VPackSlice(vpack, start + dataOffset);
n = (end - dataOffset) / first.GetByteSize();
}
else if (offsetsize < 8)
{
n = NumberUtil.ToLong(vpack, start + 1 + offsetsize, offsetsize);
}
else
{
n = NumberUtil.ToLong(vpack, (int)(start + end - offsetsize), offsetsize);
}
if (index >= n)
{
throw new IndexOutOfRangeException();
}
if (head <= 0x05 || n == 1)
{
// no index table, but all array items have the same length
// or only one item is in the array
// now fetch first item and determine its length
if (dataOffset == 0)
{
dataOffset = FindDataOffset();
}
offset = dataOffset + index * new VPackSlice(vpack, start + dataOffset).GetByteSize();
}
else
{
long ieBase = end - n * offsetsize + index * offsetsize - (offsetsize == 8 ? 8 : 0);
offset = (int)NumberUtil.ToLong(vpack, (int)(start + ieBase), offsetsize);
}
}
return(offset);
}
/// <exception cref="VPackException"/>
public virtual VPackSlice Get(string attribute)
{
if (!this.IsObject)
{
throw new VPackValueTypeException(ValueType.OBJECT);
}
byte head = Head;
VPackSlice result = new VPackSlice();
if (head == 0x0a)
{
// special case, empty object
result = new VPackSlice();
}
else
{
if (head == 0x14)
{
// compact Object
result = this.GetFromCompactObject(attribute);
}
else
{
int offsetsize = ObjectArrayUtil.GetOffsetSize(head);
long end = NumberUtil.ToLong(this.vpack, this.start + 1, offsetsize);
long n;
if (offsetsize < 8)
{
n = NumberUtil.ToLong(this.vpack, this.start + 1 + offsetsize, offsetsize);
}
else
{
n = NumberUtil.ToLong(this.vpack, (int)(this.start + end - offsetsize), offsetsize);
}
if (n == 1)
{
// Just one attribute, there is no index table!
VPackSlice key = new VPackSlice(this.vpack, this.start + this.FindDataOffset());
if (key.IsString)
{
if (key.IsEqualString(attribute))
{
result = new VPackSlice(this.vpack, key.start + key.ByteSize);
}
else
{
// no match
result = new VPackSlice();
}
}
else
{
if (key.IsInteger)
{
// translate key
if (attributeTranslator == null)
{
throw new VPackNeedAttributeTranslatorException();
}
if (key.TranslateUnchecked().IsEqualString(attribute))
{
result = new VPackSlice(this.vpack, key.start + key.ByteSize);
}
else
{
// no match
result = new VPackSlice();
}
}
else
{
// no match
result = new VPackSlice();
}
}
}
else
{
long ieBase = end - n * offsetsize - (offsetsize == 8 ? 8 : 0);
// only use binary search for attributes if we have at least
// this many entries
// otherwise we'll always use the linear search
long sortedSearchEntriesThreshold = 4;
bool sorted = head >= 0x0b && (sbyte)head <= 0x0e;
if (sorted && n >= sortedSearchEntriesThreshold)
{
// This means, we have to handle the special case n == 1
// only in the linear search!
result = this.SearchObjectKeyBinary(attribute, ieBase, offsetsize, n);
}
else
{
result = this.SearchObjectKeyLinear(attribute, ieBase, offsetsize, n);
}
}
}
}
return(result);
}
internal int GetByteSize()
{
long size;
byte head = TypeCode;
int valueLength = ValueLengthUtil.Get(head);
if (valueLength != 0)
{
size = valueLength;
}
else
{
switch (Type)
{
case SliceType.Array:
case SliceType.Object:
if (head == 0x13 || head == 0x14)
{
// compact Array or Object
size = NumberUtil.ReadVariableValueLength(vpack, start + 1, false);
}
else /* if (head <= 0x14) */
{
size = NumberUtil.ToLong(vpack, start + 1, ObjectArrayUtil.GetOffsetSize(head));
}
break;
case SliceType.String:
// long UTF-8 String
size = GetLongStringLength() + 1 + 8;
break;
case SliceType.Binary:
size = 1 + head - ((byte)0xbf) + GetBinaryLengthUnchecked();
break;
case SliceType.Bcd:
if (head <= 0xcf)
{
size = 1 + head + ((byte)0xc7) + NumberUtil.ToLong(vpack, start + 1, head - ((byte)0xc7));
}
else
{
size = 1 + head - ((byte)0xcf) + NumberUtil.ToLong(vpack, start + 1, head - ((byte)0xcf));
}
break;
case SliceType.Custom:
if (head == 0xf4 || head == 0xf5 || head == 0xf6)
{
size = 2 + NumberUtil.ToLong(vpack, start + 1, 1);
}
else if (head == 0xf7 || head == 0xf8 || head == 0xf9)
{
size = 3 + NumberUtil.ToLong(vpack, start + 1, 2);
}
else if (head == 0xfa || head == 0xfb || head == 0xfc)
{
size = 5 + NumberUtil.ToLong(vpack, start + 1, 4);
}
else /* if (head == 0xfd || head == 0xfe || head == 0xff) */
{
size = 9 + NumberUtil.ToLong(vpack, start + 1, 8);
}
break;
default:
// TODO
throw new Exception("Internal error");
}
}
return((int)size);
}
