1 files changed, 243 insertions, 0 deletions
diff --git a/src/rocksdb/util/slice.cc b/src/rocksdb/util/slice.cc
new file mode 100644
index 000000000..6db11cc94
--- /dev/null
+++ b/src/rocksdb/util/slice.cc
@@ -0,0 +1,243 @@
+//  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) 2012 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.
+
+#include <algorithm>
+#include "rocksdb/slice_transform.h"
+#include "rocksdb/slice.h"
+#include "util/string_util.h"
+#include <stdio.h>
+
+namespace ROCKSDB_NAMESPACE {
+
+namespace {
+
+class FixedPrefixTransform : public SliceTransform {
+ private:
+  size_t prefix_len_;
+  std::string name_;
+
+ public:
+  explicit FixedPrefixTransform(size_t prefix_len)
+      : prefix_len_(prefix_len),
+        // Note that if any part of the name format changes, it will require
+        // changes on options_helper in order to make RocksDBOptionsParser work
+        // for the new change.
+        // TODO(yhchiang): move serialization / deserializaion code inside
+        // the class implementation itself.
+        name_("rocksdb.FixedPrefix." + ToString(prefix_len_)) {}
+
+  const char* Name() const override { return name_.c_str(); }
+
+  Slice Transform(const Slice& src) const override {
+    assert(InDomain(src));
+    return Slice(src.data(), prefix_len_);
+  }
+
+  bool InDomain(const Slice& src) const override {
+    return (src.size() >= prefix_len_);
+  }
+
+  bool InRange(const Slice& dst) const override {
+    return (dst.size() == prefix_len_);
+  }
+
+  bool FullLengthEnabled(size_t* len) const override {
+    *len = prefix_len_;
+    return true;
+  }
+
+  bool SameResultWhenAppended(const Slice& prefix) const override {
+    return InDomain(prefix);
+  }
+};
+
+class CappedPrefixTransform : public SliceTransform {
+ private:
+  size_t cap_len_;
+  std::string name_;
+
+ public:
+  explicit CappedPrefixTransform(size_t cap_len)
+      : cap_len_(cap_len),
+        // Note that if any part of the name format changes, it will require
+        // changes on options_helper in order to make RocksDBOptionsParser work
+        // for the new change.
+        // TODO(yhchiang): move serialization / deserializaion code inside
+        // the class implementation itself.
+        name_("rocksdb.CappedPrefix." + ToString(cap_len_)) {}
+
+  const char* Name() const override { return name_.c_str(); }
+
+  Slice Transform(const Slice& src) const override {
+    assert(InDomain(src));
+    return Slice(src.data(), std::min(cap_len_, src.size()));
+  }
+
+  bool InDomain(const Slice& /*src*/) const override { return true; }
+
+  bool InRange(const Slice& dst) const override {
+    return (dst.size() <= cap_len_);
+  }
+
+  bool FullLengthEnabled(size_t* len) const override {
+    *len = cap_len_;
+    return true;
+  }
+
+  bool SameResultWhenAppended(const Slice& prefix) const override {
+    return prefix.size() >= cap_len_;
+  }
+};
+
+class NoopTransform : public SliceTransform {
+ public:
+  explicit NoopTransform() { }
+
+  const char* Name() const override { return "rocksdb.Noop"; }
+
+  Slice Transform(const Slice& src) const override { return src; }
+
+  bool InDomain(const Slice& /*src*/) const override { return true; }
+
+  bool InRange(const Slice& /*dst*/) const override { return true; }
+
+  bool SameResultWhenAppended(const Slice& /*prefix*/) const override {
+    return false;
+  }
+};
+
+}
+
+// 2 small internal utility functions, for efficient hex conversions
+// and no need for snprintf, toupper etc...
+// Originally from wdt/util/EncryptionUtils.cpp - for ToString(true)/DecodeHex:
+char toHex(unsigned char v) {
+  if (v <= 9) {
+    return '0' + v;
+  }
+  return 'A' + v - 10;
+}
+// most of the code is for validation/error check
+int fromHex(char c) {
+  // toupper:
+  if (c >= 'a' && c <= 'f') {
+    c -= ('a' - 'A');  // aka 0x20
+  }
+  // validation
+  if (c < '0' || (c > '9' && (c < 'A' || c > 'F'))) {
+    return -1;  // invalid not 0-9A-F hex char
+  }
+  if (c <= '9') {
+    return c - '0';
+  }
+  return c - 'A' + 10;
+}
+
+Slice::Slice(const SliceParts& parts, std::string* buf) {
+  size_t length = 0;
+  for (int i = 0; i < parts.num_parts; ++i) {
+    length += parts.parts[i].size();
+  }
+  buf->reserve(length);
+
+  for (int i = 0; i < parts.num_parts; ++i) {
+    buf->append(parts.parts[i].data(), parts.parts[i].size());
+  }
+  data_ = buf->data();
+  size_ = buf->size();
+}
+
+// Return a string that contains the copy of the referenced data.
+std::string Slice::ToString(bool hex) const {
+  std::string result;  // RVO/NRVO/move
+  if (hex) {
+    result.reserve(2 * size_);
+    for (size_t i = 0; i < size_; ++i) {
+      unsigned char c = data_[i];
+      result.push_back(toHex(c >> 4));
+      result.push_back(toHex(c & 0xf));
+    }
+    return result;
+  } else {
+    result.assign(data_, size_);
+    return result;
+  }
+}
+
+// Originally from rocksdb/utilities/ldb_cmd.h
+bool Slice::DecodeHex(std::string* result) const {
+  std::string::size_type len = size_;
+  if (len % 2) {
+    // Hex string must be even number of hex digits to get complete bytes back
+    return false;
+  }
+  if (!result) {
+    return false;
+  }
+  result->clear();
+  result->reserve(len / 2);
+
+  for (size_t i = 0; i < len;) {
+    int h1 = fromHex(data_[i++]);
+    if (h1 < 0) {
+      return false;
+    }
+    int h2 = fromHex(data_[i++]);
+    if (h2 < 0) {
+      return false;
+    }
+    result->push_back(static_cast<char>((h1 << 4) | h2));
+  }
+  return true;
+}
+
+const SliceTransform* NewFixedPrefixTransform(size_t prefix_len) {
+  return new FixedPrefixTransform(prefix_len);
+}
+
+const SliceTransform* NewCappedPrefixTransform(size_t cap_len) {
+  return new CappedPrefixTransform(cap_len);
+}
+
+const SliceTransform* NewNoopTransform() {
+  return new NoopTransform;
+}
+
+PinnableSlice::PinnableSlice(PinnableSlice&& other) {
+  *this = std::move(other);
+}
+
+PinnableSlice& PinnableSlice::operator=(PinnableSlice&& other) {
+  if (this != &other) {
+    Cleanable::Reset();
+    Cleanable::operator=(std::move(other));
+    size_ = other.size_;
+    pinned_ = other.pinned_;
+    if (pinned_) {
+      data_ = other.data_;
+      // When it's pinned, buf should no longer be of use.
+    } else {
+      if (other.buf_ == &other.self_space_) {
+        self_space_ = std::move(other.self_space_);
+        buf_ = &self_space_;
+        data_ = buf_->data();
+      } else {
+        buf_ = other.buf_;
+        data_ = other.data_;
+      }
+    }
+    other.self_space_.clear();
+    other.buf_ = &other.self_space_;
+    other.pinned_ = false;
+    other.PinSelf();
+  }
+  return *this;
+}
+
+}  // namespace ROCKSDB_NAMESPACE