public static void EncodeFixed32(ByteArrayPointer buf, UInt32 value)
{
buf[0] = (byte)(value & 0xff);
buf[1] = (byte)((value >> 8) & 0xff);
buf[2] = (byte)((value >> 16) & 0xff);
buf[3] = (byte)((value >> 24) & 0xff);
}
// Add an entry into memtable that maps key to value at the
// specified sequence number and with the specified type.
// Typically value will be empty if type==kTypeDeletion.
public void Add(UInt64 seq, int type,
Slice key,
Slice value)
{
// Format of an entry is concatenation of:
// key_size : varint32 of internal_key.size()
// key bytes : char[internal_key.size()]
// value_size : varint32 of value.size()
// value bytes : char[value.size()]
int key_size = key.Size;
int val_size = value.Size;
int internal_key_size = key_size + 8;
int encoded_len =
Coding.VarintLength(internal_key_size) + internal_key_size +
Coding.VarintLength(val_size) + val_size;
ByteArrayPointer buf = new ByteArrayPointer(encoded_len);
ByteArrayPointer p = Coding.EncodeVarint32(buf, (uint)internal_key_size);
key.Data.CopyTo(p, key_size);
p += key_size;
Coding.EncodeFixed64(p, (seq << 8) | (UInt64)type);
p += 8;
p = Coding.EncodeVarint32(p, (uint)val_size);
value.Data.CopyTo(p, val_size);
Debug.Assert((p + val_size) - buf == encoded_len);
m_table.Insert(buf);
}
// Helper routine: decode the next block entry starting at "p",
// storing the number of shared key bytes, non_shared key bytes,
// and the length of the value in "*shared", "*non_shared", and
// "*value_length", respectively. Will not derefence past "limit".
//
// If any errors are detected, returns NULL. Otherwise, returns a
// pointer to the key delta (just past the three decoded values).
private static ByteArrayPointer DecodeEntry(ByteArrayPointer p, ByteArrayPointer limit,
out UInt32 shared,
out UInt32 non_shared,
out UInt32 value_length)
{
if (limit - p < 3)
{
shared = non_shared = value_length = 0;
return ByteArrayPointer.Null;
}
shared = p[0];
non_shared = p[1];
value_length = p[3];
if ((shared | non_shared | value_length) < 128)
{
// Fast path: all three values are encoded in one byte each
p += 3;
}
else
{
if ((p = Coding.GetVarint32Ptr(p, limit, out shared)) == ByteArrayPointer.Null) return ByteArrayPointer.Null;
if ((p = Coding.GetVarint32Ptr(p, limit, out non_shared)) == ByteArrayPointer.Null) return ByteArrayPointer.Null;
if ((p = Coding.GetVarint32Ptr(p, limit, out value_length)) == ByteArrayPointer.Null) return ByteArrayPointer.Null;
}
if ((limit - p) < (non_shared + value_length))
{
return ByteArrayPointer.Null;
}
return p;
}
public int Compare(ByteArrayPointer aptr, ByteArrayPointer bptr)
{
// Internal keys are encoded as length-prefixed strings.
Slice a = MemTable.GetLengthPrefixedSlice(aptr);
Slice b = MemTable.GetLengthPrefixedSlice(bptr);
return Comparator.Compare(a, b);
}
public static UInt32 DecodeFixed32(ByteArrayPointer ptr)
{
return ((UInt32)ptr[0])
| (((UInt32)ptr[1]) << 8)
| (((UInt32)ptr[2]) << 16)
| (((UInt32)ptr[3]) << 24);
}
// Initialize *this for looking up user_key at a snapshot with
// the specified sequence number.
public LookupKey(Slice user_key, UInt64 sequence)
{
int usize = user_key.Size;
int needed = usize + 13; // A conservative estimate
ByteArrayPointer dst;
if (needed <= space_.Length)
{
dst = new ByteArrayPointer(space_);
}
else
{
dst = new ByteArrayPointer(needed);
}
start_ = dst;
dst = Coding.EncodeVarint32(dst, (uint)(usize + 8));
kstart_ = dst;
user_key.Data.CopyTo(dst, usize);
dst += usize;
Coding.EncodeFixed64(dst, Global.PackSequenceAndType(sequence ,Global.kValueTypeForSeek));
end_ = dst + 8;
}
public static void EncodeFixed64(ByteArrayPointer buf, UInt64 value)
{
buf[0] = (byte)(value & 0xff);
buf[1] = (byte)((value >> 8) & 0xff);
buf[2] = (byte)((value >> 16) & 0xff);
buf[3] = (byte)((value >> 24) & 0xff);
buf[4] = (byte)((value >> 32) & 0xff);
buf[5] = (byte)((value >> 40) & 0xff);
buf[6] = (byte)((value >> 48) & 0xff);
buf[7] = (byte)((value >> 56) & 0xff);
}
/// <summary>
/// Attempt to open the table that is stored in bytes [0..file_size)
/// of "file", and read the metadata entries necessary to allow
/// retrieving data from the table.
///
/// If successful, returns ok and sets "*table" to the newly opened
/// table. The client should delete "*table" when no longer needed.
/// If there was an error while initializing the table, sets "*table"
/// to NULL and returns a non-ok status. Does not take ownership of
/// "*source", but the client must ensure that "source" remains live
/// for the duration of the returned table's lifetime.
///
/// *file must remain live while this Table is in use.
/// </summary>
public static Status Open(Options options, RandomAccessFile file, UInt64 size, out Table table)
{
table = null;
if (size < Footer.kEncodedLength)
{
return Status.InvalidArgument("file is too short to be an sstable");
}
ByteArrayPointer footerSpace = new ByteArrayPointer(Footer.kEncodedLength);
Slice footerInput;
Status s = file.Read(size - Footer.kEncodedLength, Footer.kEncodedLength, out footerInput, footerSpace);
if (!s.IsOk) return s;
Footer footer = new Footer();
s = footer.DecodeFrom(ref footerInput);
if (!s.IsOk) return s;
// Read the index block
BlockContents contents;
Block indexBlock = null;
if (s.IsOk)
{
s = FormatHelper.ReadBlock(file, ReadOptions.Default, footer.IndexHandle, out contents);
if (s.IsOk)
{
indexBlock = new Block(contents);
}
}
if (s.IsOk)
{
// We've successfully read the footer and the index block: we're
// ready to serve requests.
Rep rep = new Rep();
rep.Options = options;
rep.File = file;
rep.MetaindexHandle = footer.MetaindexHandle;
rep.IndexBlock = indexBlock;
rep.CacheId = (options.BlockCache != null ? options.BlockCache.NewId() : 0);
rep.FilterData = ByteArrayPointer.Null;
rep.Filter = null;
table = new Table(rep);
table.ReadMeta(footer);
}
return s;
}
// REQUIRES: "contents" and *policy must stay live while *this is live.
public FilterBlockReader(FilterPolicy policy, Slice contents)
{
policy_ = policy;
data_ = ByteArrayPointer.Null;
offset_ = ByteArrayPointer.Null;
num_ = 0;
base_lg_ = 0;
int n = contents.Size;
if (n < 5) return; // 1 byte for base_lg_ and 4 for start of offset array
base_lg_ = contents[n - 1];
UInt32 last_word = Coding.DecodeFixed32(contents.Data + n - 5);
if (last_word > n - 5) return;
data_ = contents.Data;
offset_ = data_ + (int)last_word;
num_ = (int)((n - 5 - last_word) / 4);
}
public static ByteArrayPointer EncodeVarint32(ByteArrayPointer dst, UInt32 v)
{
// Operate on characters as unsigneds
ByteArrayPointer ptr = dst;
int B = 128;
if (v < (1 << 7))
{
ptr[0] = (byte)v;
ptr += 1;
}
else if (v < (1 << 14))
{
ptr[0] = (byte)(v | B);
ptr[1] = (byte)(v >> 7);
ptr += 2;
}
else if (v < (1 << 21))
{
ptr[0] = (byte)(v | B);
ptr[1] = (byte)((v >> 7) | B);
ptr[2] = (byte)(v >> 14);
ptr += 3;
}
else if (v < (1 << 28))
{
ptr[0] = (byte)(v | B);
ptr[1] = (byte)((v >> 7) | B);
ptr[2] = (byte)((v >> 14) | B);
ptr[3] = (byte)(v >> 21);
ptr += 4;
}
else
{
ptr[0] = (byte)(v | B);
ptr[1] = (byte)((v >> 7) | B);
ptr[2] = (byte)((v >> 14) | B);
ptr[3] = (byte)((v >> 21) | B);
ptr[4] = (byte)(v >> 28);
ptr += 5;
}
return ptr;
}
// Initialize the block with the specified contents.
public Block(BlockContents contents)
{
data_ = contents.Data.Data;
size_ = contents.Data.Size;
owned_ = contents.HeapAllocated;
if (size_ < sizeof(UInt32))
{
size_ = 0; // Error marker
}
else
{
restart_offset_ = (uint)(size_ - (1 + NumRestarts()) * sizeof(UInt32));
if (restart_offset_ > size_ - sizeof(UInt32))
{
// The size is too small for NumRestarts() and therefore
// restart_offset_ wrapped around.
size_ = 0;
}
}
}
public static ByteArrayPointer EncodeVarint64(ByteArrayPointer dst, UInt64 v)
{
const int B = 128;
ByteArrayPointer ptr = dst;
while (v >= B)
{
ptr[0] = (byte)((v & (B - 1)) | B);
ptr += 1;
v >>= 7;
}
ptr[0] = (byte)v;
ptr += 1;
return ptr;
}
// Return the earliest node that comes at or after key.
// Return NULL if there is no such node.
//
// If prev is non-NULL, fills prev[level] with pointer to previous
// node at "level" for every level in [0..max_height_-1].
private Node FindGreaterOrEqual(ByteArrayPointer key, Node[] prev)
{
Node x = head_;
int level = MaxHeight - 1;
while (true)
{
Node next = x.Next(level);
if (KeyIsAfterNode(key, next))
{
// Keep searching in this list
x = next;
}
else
{
if (prev != null) prev[level] = x;
if (level == 0)
{
return next;
}
else
{
// Switch to next list
level--;
}
}
}
}
// Return the latest node with a key < key.
// Return head_ if there is no such node.
private Node FindLessThan(ByteArrayPointer key)
{
Node x = head_;
int level = MaxHeight - 1;
while (true)
{
Debug.Assert(x == head_ || compare_.Compare(x.Key, key) < 0);
Node next = x.Next(level);
if (next == null || compare_.Compare(next.Key, key) >= 0)
{
if (level == 0)
{
return x;
}
else
{
// Switch to next list
level--;
}
}
else
{
x = next;
}
}
}
// Advance to the first entry with a key >= target
public void Seek(ByteArrayPointer target)
{
node_ = list_.FindGreaterOrEqual(target, null);
}
// Insert key into the list.
// REQUIRES: nothing that compares equal to key is currently in the list.
public void Insert(ByteArrayPointer key)
{
// TODO(opt): We can use a barrier-free variant of FindGreaterOrEqual()
// here since Insert() is externally synchronized.
Node[] prev = new Node[kMaxHeight];
Node x = FindGreaterOrEqual(key, prev);
// Our data structure does not allow duplicate insertion
Debug.Assert(x == null || !Equal(key, x.Key));
int height = RandomHeight();
if (height > MaxHeight)
{
for (int i = MaxHeight; i < height; i++)
{
prev[i] = head_;
}
//fprintf(stderr, "Change height from %d to %d\n", max_height_, height);
// It is ok to mutate max_height_ without any synchronization
// with concurrent readers. A concurrent reader that observes
// the new value of max_height_ will see either the old value of
// new level pointers from head_ (NULL), or a new value set in
// the loop below. In the former case the reader will
// immediately drop to the next level since NULL sorts after all
// keys. In the latter case the reader will use the new node.
max_height_.NoBarrierStore(height);
}
x = NewNode(key, height);
for (int i = 0; i < height; i++)
{
// NoBarrier_SetNext() suffices since we will add a barrier when
// we publish a pointer to "x" in prev[i].
x.NoBarrier_SetNext(i, prev[i].NoBarrierNext(i));
prev[i].SetNext(i, x);
}
}
public Iter(Comparator comparator,
ByteArrayPointer data,
UInt32 restarts,
UInt32 num_restarts)
{
comparator_ = comparator;
data_ = data;
restarts_ = restarts;
num_restarts_ = num_restarts;
current_ = restarts_;
restart_index_ = num_restarts_;
Debug.Assert(num_restarts_ > 0);
}
public static UInt64 DecodeFixed64(ByteArrayPointer ptr)
{
UInt64 lo = DecodeFixed32(ptr);
UInt64 hi = DecodeFixed32(ptr + 4);
return (hi << 32) | lo;
}
private static Iterator BlockReader(object arg, ReadOptions options, Slice indexValue)
{
Table table = (Table)arg;
Cache blockCache = table.rep_.Options.BlockCache;
Block block = null;
Cache.Handle cacheHandle = null;
BlockHandle handle = new BlockHandle();
Slice input = indexValue;
Status s = handle.DecodeFrom(ref input);
// We intentionally allow extra stuff in index_value so that we
// can add more features in the future.
if (s.IsOk)
{
BlockContents contents;
if (blockCache != null)
{
ByteArrayPointer cacheKeyBuffer = new ByteArrayPointer(16);
Coding.EncodeFixed64(cacheKeyBuffer, table.rep_.CacheId);
Coding.EncodeFixed64(cacheKeyBuffer + 8, handle.Offset);
Slice key = new Slice(cacheKeyBuffer, cacheKeyBuffer.Length);
cacheHandle = blockCache.Lookup(key);
if (cacheHandle != null)
{
block = (Block)(blockCache.Value(cacheHandle));
}
else
{
s = FormatHelper.ReadBlock(table.rep_.File, options, handle, out contents);
if (s.IsOk)
{
block = new Block(contents);
if (contents.Cachable && options.FillCache)
{
cacheHandle = blockCache.Insert(key, block, block.Size);
}
}
}
}
else
{
s = FormatHelper.ReadBlock(table.rep_.File, options, handle, out contents);
if (s.IsOk)
{
block = new Block(contents);
}
}
}
Iterator iter;
if (block != null)
{
iter = block.NewIterator(table.rep_.Options.Comparator);
if (cacheHandle != null)
{
iter.RegisterCleanup(ReleaseBlock, blockCache, cacheHandle);
}
}
else
{
iter = Iterator.NewErrorIterator(s);
}
return iter;
}
// Return true if key is greater than the data stored in "n"
private bool KeyIsAfterNode(ByteArrayPointer key, Node n)
{
// NULL n is considered infinite
//return (n != null) && (compare_(n->key, key) < 0);
return (n != null) && (compare_.Compare(n.Key, key) < 0);
}
public static ByteArrayPointer GetLengthPrefixedSlice(ByteArrayPointer p, ByteArrayPointer limit,
out Slice result)
{
result = null;
UInt32 len;
p = GetVarint32Ptr(p, limit, out len);
if (p.IsNull) return p;
if (p + (int)len > limit) return ByteArrayPointer.Null;
result = new Slice(p, (int)len);
return p + (int)len;
}
// Returns true iff an entry that compares equal to key is in the list.
public bool Contains(ByteArrayPointer key)
{
Node x = FindGreaterOrEqual(key, null);
if (x != null && Equal(key, x.Key))
{
return true;
}
else
{
return false;
}
}
public Node(ByteArrayPointer k, int height)
{
Key = k;
next_ = new AtomicPointer<Node>[height];
}
internal static Slice GetLengthPrefixedSlice(ByteArrayPointer data)
{
UInt32 len;
ByteArrayPointer p = data;
p = Coding.GetVarint32Ptr(p, p + 5, out len); // +5: we assume "p" is not corrupted
return new Slice(p, (int)len);
}
private bool Equal(ByteArrayPointer a, ByteArrayPointer b)
{
return (compare_.Compare(a, b) == 0);
}
public static ByteArrayPointer GetVarint64Ptr(ByteArrayPointer p, ByteArrayPointer limit, out UInt64 value)
{
UInt64 result = 0;
for (int shift = 0; shift <= 63 && p < limit; shift += 7)
{
UInt64 b = p[0];
p += 1;
if ((b & 128) != 0)
{
// More bytes are present
result |= ((b & 127) << shift);
}
else
{
result |= (b << shift);
value = result;
return p;
}
}
value = 0;
return ByteArrayPointer.Null;
}
public static void PutFixed64(ref string dst, UInt64 value)
{
ByteArrayPointer buf = new ByteArrayPointer(sizeof(UInt64));
EncodeFixed64(buf, value);
dst += buf.GetString(buf.Length);
}
public static void PutVarint64(ref string dst, UInt64 v)
{
ByteArrayPointer buf = new ByteArrayPointer(10);
ByteArrayPointer ptr = EncodeVarint64(buf, v);
dst += buf.GetString(ptr - buf);
}
public static ByteArrayPointer GetVarint32Ptr(ByteArrayPointer p,
ByteArrayPointer limit,
out UInt32 value)
{
if (p < limit)
{
UInt32 result = p[0];
if ((result & 128) == 0)
{
value = result;
return new ByteArrayPointer(p, 1);
}
}
return GetVarint32PtrFallback(p, limit, out value);
}
private Node NewNode(ByteArrayPointer key, int height)
{
var node = new Node(key, height);
return node;
}