1 files changed, 288 insertions, 37 deletions
diff --git a/db/memtable.cuh b/db/memtable.cuh
index 766eb03..6f0b2cd 100644
--- a/db/memtable.cuh
+++ b/db/memtable.cuh
@@ -18,36 +18,6 @@ namespace leveldb {
 class InternalKeyComparator;
 class MemTableIterator;
 
-__device__ const char* GetVarint32PtrFallbackCuda(const char* p, const char* limit,
-                                                  uint32_t* value) {
-  uint32_t result = 0;
-  for (uint32_t shift = 0; shift <= 28 && p < limit; shift += 7) {
-    uint32_t byte = *(reinterpret_cast<const uint8_t*>(p));
-    p++;
-    if (byte & 128) {
-      // More bytes are present
-      result |= ((byte & 127) << shift);
-    } else {
-      result |= (byte << shift);
-      *value = result;
-      return reinterpret_cast<const char*>(p);
-    }
-  }
-  return nullptr;
-}
-
-__device__ inline const char* GetVarint32PtrCuda(const char* p, const char* limit,
-                                                 uint32_t* value) {
-  if (p < limit) {
-    uint32_t result = *(reinterpret_cast<const uint8_t*>(p));
-    if ((result & 128) == 0) {
-      *value = result;
-      return p + 1;
-    }
-  }
-  return GetVarint32PtrFallbackCuda(p, limit, value);
-}
-
 struct SizedString {
   char * data;
   size_t length;
@@ -73,13 +43,6 @@ struct SizedString {
 };
 
 
-__device__ static SizedString GetLengthPrefixedSliceCuda(const char* data) {
-  uint32_t len;
-  const char* p = data;
-  p = GetVarint32PtrCuda(p, p + 5, &len);  // +5: we assume "p" is not corrupted
-  return SizedString(p, len);
-}
-
 class MemTable {
  public:
   // MemTables are reference counted.  The initial reference count
@@ -154,6 +117,294 @@ class MemTable {
   Table table_;
 };
 
+
+class CudaSlice;
+
+// A Comparator object provides a total order across slices that are
+// used as keys in an sstable or a database.  A Comparator implementation
+// must be thread-safe since leveldb may invoke its methods concurrently
+// from multiple threads.
+class LEVELDB_EXPORT CudaComparator {
+ public:
+  virtual ~CudaComparator();
+
+  virtual  __device__ int Compare(const CudaSlice& a, const CudaSlice& b) const = 0;
+
+  virtual __device__ __host__ const char* Name() const = 0;
+
+  virtual __device__ void FindShortestSeparator(const CudaSlice* start,
+                                     const CudaSlice& limit) const = 0;
+
+  virtual __device__ void FindShortSuccessor(CudaSlice* key) const = 0;
+};
+
+// Return a builtin comparator that uses lexicographic byte-wise
+// ordering.  The result remains the property of this module and
+// must not be deleted.
+LEVELDB_EXPORT const Comparator* BytewiseComparator();
+
+
+// A comparator for internal keys that uses a specified comparator for
+// the user key portion and breaks ties by decreasing sequence number.
+class CudaInternalKeyComparator : public CudaComparator {
+ private:
+  const CudaComparator* user_comparator_;
+
+ public:
+  explicit CudaInternalKeyComparator(const CudaComparator* c) : user_comparator_(c) {}
+  __device__ __host__ const char* Name() const override;
+  __device__ int Compare(const CudaSlice& a, const CudaSlice& b) const override;
+  __device__ void FindShortestSeparator(const CudaSlice* start,
+                             const CudaSlice& limit) const override;
+  __device__ void FindShortSuccessor(CudaSlice* key) const override;
+
+  __device__ __host__ const CudaComparator* user_comparator() const { return user_comparator_; }
+
+  __device__ int Compare(const InternalKey& a, const InternalKey& b) const;
+};
+
+
+class LEVELDB_EXPORT CudaSlice {
+ public:
+  // Create an empty slice.
+  CudaSlice() : data_(""), size_(0) {}
+
+  // Create a slice that refers to d[0,n-1].
+  CudaSlice(const char* d, size_t n) : data_(d), size_(n) {}
+
+  // Create a slice that refers to the contents of "s"
+  //CudaSlice(const std::string& s) : data_(s.data()), size_(s.size()) {}
+
+  // Create a slice that refers to s[0,strlen(s)-1]
+  CudaSlice(const char* s) : data_(s), size_(strlen(s)) {}
+
+  // Intentionally copyable.
+  CudaSlice(const CudaSlice&) = default;
+  CudaSlice& operator=(const CudaSlice&) = default;
+
+  // Return a pointer to the beginning of the referenced data
+  __device__ const char* data() const { return data_; }
+
+  // Return the length (in bytes) of the referenced data
+  __device__ __host__ size_t size() const { return size_; }
+
+  // Return true iff the length of the referenced data is zero
+  __device__ __host__ bool empty() const { return size_ == 0; }
+
+  // Return the ith byte in the referenced data.
+  // REQUIRES: n < size()
+  /*__device__ char operator[](size_t n) const {
+    assert(n < size());
+    return data_[n];
+  }*/
+  __device__ char get_index(size_t n) const {
+    assert(n < size());
+    return data_[n];
+  }
+
+  // Change this slice to refer to an empty array
+  __device__ __host__ void clear() {
+    data_ = nullptr;
+    size_ = 0;
+  }
+
+  // Drop the first "n" bytes from this slice.
+  void remove_prefix(size_t n) {
+    assert(n <= size());
+    data_ += n;
+    size_ -= n;
+  }
+
+  // Return a string that contains the copy of the referenced data.
+  //std::string ToString() const { return std::string(data_, size_); }
+
+  // Three-way comparison.  Returns value:
+  //   <  0 iff "*this" <  "b",
+  //   == 0 iff "*this" == "b",
+  //   >  0 iff "*this" >  "b"
+  __device__ int compare(const CudaSlice& b) const;
+
+  // Return true iff "x" is a prefix of "*this"
+  bool starts_with(const CudaSlice& x) const {
+    return ((size_ >= x.size_) && (memcmp(data_, x.data_, x.size_) == 0));
+  }
+
+ private:
+  const char* data_;
+  size_t size_;
+};
+
+
+template<typename T>
+__device__ T cudaMin(const T & a, const T &b) {
+  return a>b?a:b;
+}
+
+CudaComparator::~CudaComparator() = default;
+
+namespace {
+class BytewiseComparatorImpl : public CudaComparator {
+ public:
+  BytewiseComparatorImpl() = default;
+
+
+
+  __device__ __host__ const char* Name() const override { return "leveldb.BytewiseComparator"; }
+
+  __device__ int Compare(const CudaSlice& a, const CudaSlice& b) const override {
+    return a.compare(b);
+  }
+
+  __device__ void FindShortestSeparator(const CudaSlice * start,
+                             const CudaSlice& limit) const override {
+    // Find length of common prefix
+    size_t min_length = std::min(start->size(), limit.size());
+    size_t diff_index = 0;
+    while ((diff_index < min_length) &&
+           ((*start)[diff_index] == limit[diff_index])) {
+      diff_index++;
+    }
+
+    if (diff_index >= min_length) {
+      // Do not shorten if one string is a prefix of the other
+    } else {
+      uint8_t diff_byte = static_cast<uint8_t>((*start)[diff_index]);
+      if (diff_byte < static_cast<uint8_t>(0xff) &&
+          diff_byte + 1 < static_cast<uint8_t>(limit[diff_index])) {
+        (*start)[diff_index]++;
+        start->resize(diff_index + 1);
+        assert(Compare(*start, limit) < 0);
+      }
+    }
+  }
+
+  void FindShortSuccessor(CudaSlice* key) const override {
+    // Find first character that can be incremented
+    size_t n = key->size();
+    for (size_t i = 0; i < n; i++) {
+      const uint8_t byte = (*key)[i];
+      if (byte != static_cast<uint8_t>(0xff)) {
+        (*key)[i] = byte + 1;
+        key->resize(i + 1);
+        return;
+      }
+    }
+    // *key is a run of 0xffs.  Leave it alone.
+  }
+};
+}  // namespace
+
+const Comparator* BytewiseComparator() {
+  static NoDestructor<BytewiseComparatorImpl> singleton;
+  return singleton.get();
+}
+
+template<typename T>
+__device__ int cudaMemcmp(const T * a, const T * b, size_t min_length) {
+  for (size_t i = 0; i < min_length ; i++) {
+    if (a[i] == b[i])
+      continue;
+    return a[i] < b[i] ? -1 : 1;
+  }
+  return 0;
+}
+
+/*__device__ inline bool operator==(const CudaSlice& x, const CudaSlice& y) {
+  return ((x.size() == y.size()) &&
+          (cudaMemcmp(x.data(), y.data(), x.size()) == 0));
+}*/
+
+/*inline bool operator!=(const CudaSlice& x, const CudaSlice& y) { return !(x == y); }*/
+
+
+
+__device__ inline int CudaSlice::compare(const CudaSlice& b) const {
+  const size_t min_len = (size_ < b.size_) ? size_ : b.size_;
+  int r = cudaMemcmp(data_, b.data_, min_len);
+  if (r == 0) {
+    if (size_ < b.size_)
+      r = -1;
+    else if (size_ > b.size_)
+      r = +1;
+  }
+  return r;
+}
+
+
+
+class MemTableCuda {
+ public:
+  // MemTables are reference counted.  The initial reference count
+  // is zero and the caller must call Ref() at least once.
+  __device__ explicit MemTableCuda(const InternalKeyComparator& comparator);
+
+  MemTableCuda(const MemTableCuda&) = delete;
+  MemTableCuda& operator=(const MemTableCuda&) = delete;
+
+  // Increase reference count.
+  void Ref() { ++refs_; }
+
+  // Drop reference count.  Delete if no more references exist.
+  void Unref() {
+    --refs_;
+    assert(refs_ >= 0);
+    if (refs_ <= 0) {
+      delete this;
+    }
+  }
+
+  // Returns an estimate of the number of bytes of data in use by this
+  // data structure. It is safe to call when MemTable is being modified.
+  size_t ApproximateMemoryUsage();
+
+  // Return an iterator that yields the contents of the memtable.
+  //
+  // The caller must ensure that the underlying MemTable remains live
+  // while the returned iterator is live.  The keys returned by this
+  // iterator are internal keys encoded by AppendInternalKey in the
+  // db/format.{h,cc} module.
+  Iterator* NewIterator();
+
+  // 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.
+  __device__ void Add(SequenceNumber seq, ValueType type, const CudaSlice& key,
+           const Slice& value);
+
+  // If memtable contains a value for key, store it in *value and return true.
+  // If memtable contains a deletion for key, store a NotFound() error
+  // in *status and return true.
+  // Else, return false.
+  __device__ bool Get(const LookupKey& key, std::string* value, Status* s);
+
+ private:
+  friend class MemTableCudaIterator;
+  friend class MemTableCudaBackwardIterator;
+  friend __global__ void MemTableCudaAdd_(MemTableCuda *, size_t, char *);
+  friend __global__ void MemTableCudaGet_(MemTableCuda *, char *, char **, size_t* malloc_size);
+
+  struct KeyComparator {
+    const InternalKeyComparator comparator;
+    __device__ __host__ explicit KeyComparator(const InternalKeyComparator& c) : comparator(c) {}
+    __device__ int operator()(const char* a, const char* b) const;
+    __device__ __host__ ~KeyComparator() = default;
+  };
+
+  typedef SkipList<const char*, KeyComparator> Table;
+
+  __device__  Table::Iterator getIter() {
+    Table::Iterator iter(&this->table_);
+    return iter;
+  }
+
+  ~MemTableCuda();  // Private since only Unref() should be used to delete it
+
+  KeyComparator comparator_;
+  int refs_;
+  ArenaCuda arena_;
+  Table table_;
+};
+
 }  // namespace leveldb
 
 #endif  // STORAGE_LEVELDB_DB_MEMTABLE_H_