public void CopyTo(ref VarLenType dst)
{
var fulllength = length * sizeof(int);
Buffer.MemoryCopy(Unsafe.AsPointer(ref this),
Unsafe.AsPointer(ref dst), fulllength, fulllength);
}
// This sample represents an unsafe advanced use of FASTER to store and index variable
// length keys and/or values without a separate object log. The basic idea is to use
// "ref struct" as a proxy for pointers to variable-sized memory in C#. These objects are
// placed contiguously in the single hybrid log, leading to efficient packing while
// avoiding the additional I/O (on reads and writes) that a separate object log entails.
// Users provide information on the actual length of the data underlying the types, by
// providing implementations for an IVariableLengthStruct<T> interface. Serializers are not
// required, as these are effectively value-types. One may provide safe APIs on top of
// this raw functionality using, for example, Span<T> and Memory<T>.
static unsafe void Main()
{
// VarLen types do not need an object log
var log = Devices.CreateLogDevice("hlog.log", deleteOnClose: true);
// Create store, you provide VariableLengthStructSettings for VarLen types
var store = new FasterKV <VarLenType, VarLenType>(
size: 1L << 20,
logSettings: new LogSettings {
LogDevice = log, MemorySizeBits = 17, PageSizeBits = 12
},
comparer: new VarLenTypeComparer(),
variableLengthStructSettings: new VariableLengthStructSettings <VarLenType, VarLenType>
{
keyLength = new VarLenLength(), valueLength = new VarLenLength()
}
);
// Create session
var s = store.For(new VarLenFunctions()).NewSession <VarLenFunctions>();
Random r = new Random(100);
for (int i = 0; i < 5000; i++)
{
var keylen = 2 + r.Next(10);
int * keyval = stackalloc int[keylen];
ref VarLenType key1 = ref *(VarLenType *)keyval;
key1.length = keylen;
for (int j = 1; j < keylen; j++)
{
*(keyval + j) = i;
}
var len = 2 + r.Next(10);
int * val = stackalloc int[len];
ref VarLenType value = ref *(VarLenType *)val;
