Adding upstream version 14.2.21.upstream/14.2.21upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 259 insertions, 0 deletions

diff --git a/src/rocksdb/include/rocksdb/slice.h b/src/rocksdb/include/rocksdb/slice.h
new file mode 100644
index 00000000..2b01e6d9
--- /dev/null
+++ b/src/rocksdb/include/rocksdb/slice.h
@@ -0,0 +1,259 @@
+// Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+//
+// Slice is a simple structure containing a pointer into some external
+// storage and a size.  The user of a Slice must ensure that the slice
+// is not used after the corresponding external storage has been
+// deallocated.
+//
+// Multiple threads can invoke const methods on a Slice without
+// external synchronization, but if any of the threads may call a
+// non-const method, all threads accessing the same Slice must use
+// external synchronization.
+
+#pragma once
+
+#include <assert.h>
+#include <stddef.h>
+#include <string.h>
+#include <cstdio>
+#include <string>
+
+#ifdef __cpp_lib_string_view
+#include <string_view>
+#endif
+
+#include "rocksdb/cleanable.h"
+
+namespace rocksdb {
+
+class Slice {
+ public:
+  // Create an empty slice.
+  Slice() : data_(""), size_(0) {}
+
+  // Create a slice that refers to d[0,n-1].
+  Slice(const char* d, size_t n) : data_(d), size_(n) {}
+
+  // Create a slice that refers to the contents of "s"
+  /* implicit */
+  Slice(const std::string& s) : data_(s.data()), size_(s.size()) {}
+
+#ifdef __cpp_lib_string_view
+  // Create a slice that refers to the same contents as "sv"
+  /* implicit */
+  Slice(std::string_view sv) : data_(sv.data()), size_(sv.size()) {}
+#endif
+
+  // Create a slice that refers to s[0,strlen(s)-1]
+  /* implicit */
+  Slice(const char* s) : data_(s) { size_ = (s == nullptr) ? 0 : strlen(s); }
+
+  // Create a single slice from SliceParts using buf as storage.
+  // buf must exist as long as the returned Slice exists.
+  Slice(const struct SliceParts& parts, std::string* buf);
+
+  // Return a pointer to the beginning of the referenced data
+  const char* data() const { return data_; }
+
+  // Return the length (in bytes) of the referenced data
+  size_t size() const { return size_; }
+
+  // Return true iff the length of the referenced data is zero
+  bool empty() const { return size_ == 0; }
+
+  // Return the ith byte in the referenced data.
+  // REQUIRES: n < size()
+  char operator[](size_t n) const {
+    assert(n < size());
+    return data_[n];
+  }
+
+  // Change this slice to refer to an empty array
+  void clear() {
+    data_ = "";
+    size_ = 0;
+  }
+
+  // Drop the first "n" bytes from this slice.
+  void remove_prefix(size_t n) {
+    assert(n <= size());
+    data_ += n;
+    size_ -= n;
+  }
+
+  void remove_suffix(size_t n) {
+    assert(n <= size());
+    size_ -= n;
+  }
+
+  // Return a string that contains the copy of the referenced data.
+  // when hex is true, returns a string of twice the length hex encoded (0-9A-F)
+  std::string ToString(bool hex = false) const;
+
+#ifdef __cpp_lib_string_view
+  // Return a string_view that references the same data as this slice.
+  std::string_view ToStringView() const {
+    return std::string_view(data_, size_);
+  }
+#endif
+
+  // Decodes the current slice interpreted as an hexadecimal string into result,
+  // if successful returns true, if this isn't a valid hex string
+  // (e.g not coming from Slice::ToString(true)) DecodeHex returns false.
+  // This slice is expected to have an even number of 0-9A-F characters
+  // also accepts lowercase (a-f)
+  bool DecodeHex(std::string* result) const;
+
+  // Three-way comparison.  Returns value:
+  //   <  0 iff "*this" <  "b",
+  //   == 0 iff "*this" == "b",
+  //   >  0 iff "*this" >  "b"
+  int compare(const Slice& b) const;
+
+  // Return true iff "x" is a prefix of "*this"
+  bool starts_with(const Slice& x) const {
+    return ((size_ >= x.size_) && (memcmp(data_, x.data_, x.size_) == 0));
+  }
+
+  bool ends_with(const Slice& x) const {
+    return ((size_ >= x.size_) &&
+            (memcmp(data_ + size_ - x.size_, x.data_, x.size_) == 0));
+  }
+
+  // Compare two slices and returns the first byte where they differ
+  size_t difference_offset(const Slice& b) const;
+
+  // private: make these public for rocksdbjni access
+  const char* data_;
+  size_t size_;
+
+  // Intentionally copyable
+};
+
+/**
+ * A Slice that can be pinned with some cleanup tasks, which will be run upon
+ * ::Reset() or object destruction, whichever is invoked first. This can be used
+ * to avoid memcpy by having the PinnableSlice object referring to the data
+ * that is locked in the memory and release them after the data is consumed.
+ */
+class PinnableSlice : public Slice, public Cleanable {
+ public:
+  PinnableSlice() { buf_ = &self_space_; }
+  explicit PinnableSlice(std::string* buf) { buf_ = buf; }
+
+  // No copy constructor and copy assignment allowed.
+  PinnableSlice(PinnableSlice&) = delete;
+  PinnableSlice& operator=(PinnableSlice&) = delete;
+
+  inline void PinSlice(const Slice& s, CleanupFunction f, void* arg1,
+                       void* arg2) {
+    assert(!pinned_);
+    pinned_ = true;
+    data_ = s.data();
+    size_ = s.size();
+    RegisterCleanup(f, arg1, arg2);
+    assert(pinned_);
+  }
+
+  inline void PinSlice(const Slice& s, Cleanable* cleanable) {
+    assert(!pinned_);
+    pinned_ = true;
+    data_ = s.data();
+    size_ = s.size();
+    cleanable->DelegateCleanupsTo(this);
+    assert(pinned_);
+  }
+
+  inline void PinSelf(const Slice& slice) {
+    assert(!pinned_);
+    buf_->assign(slice.data(), slice.size());
+    data_ = buf_->data();
+    size_ = buf_->size();
+    assert(!pinned_);
+  }
+
+  inline void PinSelf() {
+    assert(!pinned_);
+    data_ = buf_->data();
+    size_ = buf_->size();
+    assert(!pinned_);
+  }
+
+  void remove_suffix(size_t n) {
+    assert(n <= size());
+    if (pinned_) {
+      size_ -= n;
+    } else {
+      buf_->erase(size() - n, n);
+      PinSelf();
+    }
+  }
+
+  void remove_prefix(size_t /*n*/) {
+    assert(0);  // Not implemented
+  }
+
+  void Reset() {
+    Cleanable::Reset();
+    pinned_ = false;
+    size_ = 0;
+  }
+
+  inline std::string* GetSelf() { return buf_; }
+
+  inline bool IsPinned() { return pinned_; }
+
+ private:
+  friend class PinnableSlice4Test;
+  std::string self_space_;
+  std::string* buf_;
+  bool pinned_ = false;
+};
+
+// A set of Slices that are virtually concatenated together.  'parts' points
+// to an array of Slices.  The number of elements in the array is 'num_parts'.
+struct SliceParts {
+  SliceParts(const Slice* _parts, int _num_parts)
+      : parts(_parts), num_parts(_num_parts) {}
+  SliceParts() : parts(nullptr), num_parts(0) {}
+
+  const Slice* parts;
+  int num_parts;
+};
+
+inline bool operator==(const Slice& x, const Slice& y) {
+  return ((x.size() == y.size()) &&
+          (memcmp(x.data(), y.data(), x.size()) == 0));
+}
+
+inline bool operator!=(const Slice& x, const Slice& y) { return !(x == y); }
+
+inline int Slice::compare(const Slice& b) const {
+  assert(data_ != nullptr && b.data_ != nullptr);
+  const size_t min_len = (size_ < b.size_) ? size_ : b.size_;
+  int r = memcmp(data_, b.data_, min_len);
+  if (r == 0) {
+    if (size_ < b.size_)
+      r = -1;
+    else if (size_ > b.size_)
+      r = +1;
+  }
+  return r;
+}
+
+inline size_t Slice::difference_offset(const Slice& b) const {
+  size_t off = 0;
+  const size_t len = (size_ < b.size_) ? size_ : b.size_;
+  for (; off < len; off++) {
+    if (data_[off] != b.data_[off]) break;
+  }
+  return off;
+}
+
+}  // namespace rocksdb