Import LevelDB 1.5, it will be used for the transaction database.

33 files changed, 3808 insertions, 0 deletions

diff --git a/src/leveldb/util/arena.cc b/src/leveldb/util/arena.cc
new file mode 100644
index 0000000000..9551d6a3a2
--- /dev/null
+++ b/src/leveldb/util/arena.cc
@@ -0,0 +1,68 @@
+// 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.
+
+#include "util/arena.h"
+#include <assert.h>
+
+namespace leveldb {
+
+static const int kBlockSize = 4096;
+
+Arena::Arena() {
+  blocks_memory_ = 0;
+  alloc_ptr_ = NULL;  // First allocation will allocate a block
+  alloc_bytes_remaining_ = 0;
+}
+
+Arena::~Arena() {
+  for (size_t i = 0; i < blocks_.size(); i++) {
+    delete[] blocks_[i];
+  }
+}
+
+char* Arena::AllocateFallback(size_t bytes) {
+  if (bytes > kBlockSize / 4) {
+    // Object is more than a quarter of our block size.  Allocate it separately
+    // to avoid wasting too much space in leftover bytes.
+    char* result = AllocateNewBlock(bytes);
+    return result;
+  }
+
+  // We waste the remaining space in the current block.
+  alloc_ptr_ = AllocateNewBlock(kBlockSize);
+  alloc_bytes_remaining_ = kBlockSize;
+
+  char* result = alloc_ptr_;
+  alloc_ptr_ += bytes;
+  alloc_bytes_remaining_ -= bytes;
+  return result;
+}
+
+char* Arena::AllocateAligned(size_t bytes) {
+  const int align = sizeof(void*);    // We'll align to pointer size
+  assert((align & (align-1)) == 0);   // Pointer size should be a power of 2
+  size_t current_mod = reinterpret_cast<uintptr_t>(alloc_ptr_) & (align-1);
+  size_t slop = (current_mod == 0 ? 0 : align - current_mod);
+  size_t needed = bytes + slop;
+  char* result;
+  if (needed <= alloc_bytes_remaining_) {
+    result = alloc_ptr_ + slop;
+    alloc_ptr_ += needed;
+    alloc_bytes_remaining_ -= needed;
+  } else {
+    // AllocateFallback always returned aligned memory
+    result = AllocateFallback(bytes);
+  }
+  assert((reinterpret_cast<uintptr_t>(result) & (align-1)) == 0);
+  return result;
+}
+
+char* Arena::AllocateNewBlock(size_t block_bytes) {
+  char* result = new char[block_bytes];
+  blocks_memory_ += block_bytes;
+  blocks_.push_back(result);
+  return result;
+}
+
+}  // namespace leveldb
diff --git a/src/leveldb/util/arena.h b/src/leveldb/util/arena.h
new file mode 100644
index 0000000000..8f7dde226c
--- /dev/null
+++ b/src/leveldb/util/arena.h
@@ -0,0 +1,68 @@
+// 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.
+
+#ifndef STORAGE_LEVELDB_UTIL_ARENA_H_
+#define STORAGE_LEVELDB_UTIL_ARENA_H_
+
+#include <cstddef>
+#include <vector>
+#include <assert.h>
+#include <stdint.h>
+
+namespace leveldb {
+
+class Arena {
+ public:
+  Arena();
+  ~Arena();
+
+  // Return a pointer to a newly allocated memory block of "bytes" bytes.
+  char* Allocate(size_t bytes);
+
+  // Allocate memory with the normal alignment guarantees provided by malloc
+  char* AllocateAligned(size_t bytes);
+
+  // Returns an estimate of the total memory usage of data allocated
+  // by the arena (including space allocated but not yet used for user
+  // allocations).
+  size_t MemoryUsage() const {
+    return blocks_memory_ + blocks_.capacity() * sizeof(char*);
+  }
+
+ private:
+  char* AllocateFallback(size_t bytes);
+  char* AllocateNewBlock(size_t block_bytes);
+
+  // Allocation state
+  char* alloc_ptr_;
+  size_t alloc_bytes_remaining_;
+
+  // Array of new[] allocated memory blocks
+  std::vector<char*> blocks_;
+
+  // Bytes of memory in blocks allocated so far
+  size_t blocks_memory_;
+
+  // No copying allowed
+  Arena(const Arena&);
+  void operator=(const Arena&);
+};
+
+inline char* Arena::Allocate(size_t bytes) {
+  // The semantics of what to return are a bit messy if we allow
+  // 0-byte allocations, so we disallow them here (we don't need
+  // them for our internal use).
+  assert(bytes > 0);
+  if (bytes <= alloc_bytes_remaining_) {
+    char* result = alloc_ptr_;
+    alloc_ptr_ += bytes;
+    alloc_bytes_remaining_ -= bytes;
+    return result;
+  }
+  return AllocateFallback(bytes);
+}
+
+}  // namespace leveldb
+
+#endif  // STORAGE_LEVELDB_UTIL_ARENA_H_
diff --git a/src/leveldb/util/arena_test.cc b/src/leveldb/util/arena_test.cc
new file mode 100644
index 0000000000..63d1778034
--- /dev/null
+++ b/src/leveldb/util/arena_test.cc
@@ -0,0 +1,68 @@
+// 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.
+
+#include "util/arena.h"
+
+#include "util/random.h"
+#include "util/testharness.h"
+
+namespace leveldb {
+
+class ArenaTest { };
+
+TEST(ArenaTest, Empty) {
+  Arena arena;
+}
+
+TEST(ArenaTest, Simple) {
+  std::vector<std::pair<size_t, char*> > allocated;
+  Arena arena;
+  const int N = 100000;
+  size_t bytes = 0;
+  Random rnd(301);
+  for (int i = 0; i < N; i++) {
+    size_t s;
+    if (i % (N / 10) == 0) {
+      s = i;
+    } else {
+      s = rnd.OneIn(4000) ? rnd.Uniform(6000) :
+          (rnd.OneIn(10) ? rnd.Uniform(100) : rnd.Uniform(20));
+    }
+    if (s == 0) {
+      // Our arena disallows size 0 allocations.
+      s = 1;
+    }
+    char* r;
+    if (rnd.OneIn(10)) {
+      r = arena.AllocateAligned(s);
+    } else {
+      r = arena.Allocate(s);
+    }
+
+    for (int b = 0; b < s; b++) {
+      // Fill the "i"th allocation with a known bit pattern
+      r[b] = i % 256;
+    }
+    bytes += s;
+    allocated.push_back(std::make_pair(s, r));
+    ASSERT_GE(arena.MemoryUsage(), bytes);
+    if (i > N/10) {
+      ASSERT_LE(arena.MemoryUsage(), bytes * 1.10);
+    }
+  }
+  for (int i = 0; i < allocated.size(); i++) {
+    size_t num_bytes = allocated[i].first;
+    const char* p = allocated[i].second;
+    for (int b = 0; b < num_bytes; b++) {
+      // Check the "i"th allocation for the known bit pattern
+      ASSERT_EQ(int(p[b]) & 0xff, i % 256);
+    }
+  }
+}
+
+}  // namespace leveldb
+
+int main(int argc, char** argv) {
+  return leveldb::test::RunAllTests();
+}
diff --git a/src/leveldb/util/bloom.cc b/src/leveldb/util/bloom.cc
new file mode 100644
index 0000000000..d7941cd21f
--- /dev/null
+++ b/src/leveldb/util/bloom.cc
@@ -0,0 +1,95 @@
+// 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 "leveldb/filter_policy.h"
+
+#include "leveldb/slice.h"
+#include "util/hash.h"
+
+namespace leveldb {
+
+namespace {
+static uint32_t BloomHash(const Slice& key) {
+  return Hash(key.data(), key.size(), 0xbc9f1d34);
+}
+
+class BloomFilterPolicy : public FilterPolicy {
+ private:
+  size_t bits_per_key_;
+  size_t k_;
+
+ public:
+  explicit BloomFilterPolicy(int bits_per_key)
+      : bits_per_key_(bits_per_key) {
+    // We intentionally round down to reduce probing cost a little bit
+    k_ = static_cast<size_t>(bits_per_key * 0.69);  // 0.69 =~ ln(2)
+    if (k_ < 1) k_ = 1;
+    if (k_ > 30) k_ = 30;
+  }
+
+  virtual const char* Name() const {
+    return "leveldb.BuiltinBloomFilter";
+  }
+
+  virtual void CreateFilter(const Slice* keys, int n, std::string* dst) const {
+    // Compute bloom filter size (in both bits and bytes)
+    size_t bits = n * bits_per_key_;
+
+    // For small n, we can see a very high false positive rate.  Fix it
+    // by enforcing a minimum bloom filter length.
+    if (bits < 64) bits = 64;
+
+    size_t bytes = (bits + 7) / 8;
+    bits = bytes * 8;
+
+    const size_t init_size = dst->size();
+    dst->resize(init_size + bytes, 0);
+    dst->push_back(static_cast<char>(k_));  // Remember # of probes in filter
+    char* array = &(*dst)[init_size];
+    for (size_t i = 0; i < n; i++) {
+      // Use double-hashing to generate a sequence of hash values.
+      // See analysis in [Kirsch,Mitzenmacher 2006].
+      uint32_t h = BloomHash(keys[i]);
+      const uint32_t delta = (h >> 17) | (h << 15);  // Rotate right 17 bits
+      for (size_t j = 0; j < k_; j++) {
+        const uint32_t bitpos = h % bits;
+        array[bitpos/8] |= (1 << (bitpos % 8));
+        h += delta;
+      }
+    }
+  }
+
+  virtual bool KeyMayMatch(const Slice& key, const Slice& bloom_filter) const {
+    const size_t len = bloom_filter.size();
+    if (len < 2) return false;
+
+    const char* array = bloom_filter.data();
+    const size_t bits = (len - 1) * 8;
+
+    // Use the encoded k so that we can read filters generated by
+    // bloom filters created using different parameters.
+    const size_t k = array[len-1];
+    if (k > 30) {
+      // Reserved for potentially new encodings for short bloom filters.
+      // Consider it a match.
+      return true;
+    }
+
+    uint32_t h = BloomHash(key);
+    const uint32_t delta = (h >> 17) | (h << 15);  // Rotate right 17 bits
+    for (size_t j = 0; j < k; j++) {
+      const uint32_t bitpos = h % bits;
+      if ((array[bitpos/8] & (1 << (bitpos % 8))) == 0) return false;
+      h += delta;
+    }
+    return true;
+  }
+};
+}
+
+const FilterPolicy* NewBloomFilterPolicy(int bits_per_key) {
+  return new BloomFilterPolicy(bits_per_key);
+}
+
+}  // namespace leveldb
diff --git a/src/leveldb/util/bloom_test.cc b/src/leveldb/util/bloom_test.cc
new file mode 100644
index 0000000000..4a6ea1b7c8
--- /dev/null
+++ b/src/leveldb/util/bloom_test.cc
@@ -0,0 +1,159 @@
+// 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 "leveldb/filter_policy.h"
+
+#include "util/logging.h"
+#include "util/testharness.h"
+#include "util/testutil.h"
+
+namespace leveldb {
+
+static const int kVerbose = 1;
+
+static Slice Key(int i, char* buffer) {
+  memcpy(buffer, &i, sizeof(i));
+  return Slice(buffer, sizeof(i));
+}
+
+class BloomTest {
+ private:
+  const FilterPolicy* policy_;
+  std::string filter_;
+  std::vector<std::string> keys_;
+
+ public:
+  BloomTest() : policy_(NewBloomFilterPolicy(10)) { }
+
+  ~BloomTest() {
+    delete policy_;
+  }
+
+  void Reset() {
+    keys_.clear();
+    filter_.clear();
+  }
+
+  void Add(const Slice& s) {
+    keys_.push_back(s.ToString());
+  }
+
+  void Build() {
+    std::vector<Slice> key_slices;
+    for (size_t i = 0; i < keys_.size(); i++) {
+      key_slices.push_back(Slice(keys_[i]));
+    }
+    filter_.clear();
+    policy_->CreateFilter(&key_slices[0], key_slices.size(), &filter_);
+    keys_.clear();
+    if (kVerbose >= 2) DumpFilter();
+  }
+
+  size_t FilterSize() const {
+    return filter_.size();
+  }
+
+  void DumpFilter() {
+    fprintf(stderr, "F(");
+    for (size_t i = 0; i+1 < filter_.size(); i++) {
+      const unsigned int c = static_cast<unsigned int>(filter_[i]);
+      for (int j = 0; j < 8; j++) {
+        fprintf(stderr, "%c", (c & (1 <<j)) ? '1' : '.');
+      }
+    }
+    fprintf(stderr, ")\n");
+  }
+
+  bool Matches(const Slice& s) {
+    if (!keys_.empty()) {
+      Build();
+    }
+    return policy_->KeyMayMatch(s, filter_);
+  }
+
+  double FalsePositiveRate() {
+    char buffer[sizeof(int)];
+    int result = 0;
+    for (int i = 0; i < 10000; i++) {
+      if (Matches(Key(i + 1000000000, buffer))) {
+        result++;
+      }
+    }
+    return result / 10000.0;
+  }
+};
+
+TEST(BloomTest, EmptyFilter) {
+  ASSERT_TRUE(! Matches("hello"));
+  ASSERT_TRUE(! Matches("world"));
+}
+
+TEST(BloomTest, Small) {
+  Add("hello");
+  Add("world");
+  ASSERT_TRUE(Matches("hello"));
+  ASSERT_TRUE(Matches("world"));
+  ASSERT_TRUE(! Matches("x"));
+  ASSERT_TRUE(! Matches("foo"));
+}
+
+static int NextLength(int length) {
+  if (length < 10) {
+    length += 1;
+  } else if (length < 100) {
+    length += 10;
+  } else if (length < 1000) {
+    length += 100;
+  } else {
+    length += 1000;
+  }
+  return length;
+}
+
+TEST(BloomTest, VaryingLengths) {
+  char buffer[sizeof(int)];
+
+  // Count number of filters that significantly exceed the false positive rate
+  int mediocre_filters = 0;
+  int good_filters = 0;
+
+  for (int length = 1; length <= 10000; length = NextLength(length)) {
+    Reset();
+    for (int i = 0; i < length; i++) {
+      Add(Key(i, buffer));
+    }
+    Build();
+
+    ASSERT_LE(FilterSize(), (length * 10 / 8) + 40) << length;
+
+    // All added keys must match
+    for (int i = 0; i < length; i++) {
+      ASSERT_TRUE(Matches(Key(i, buffer)))
+          << "Length " << length << "; key " << i;
+    }
+
+    // Check false positive rate
+    double rate = FalsePositiveRate();
+    if (kVerbose >= 1) {
+      fprintf(stderr, "False positives: %5.2f%% @ length = %6d ; bytes = %6d\n",
+              rate*100.0, length, static_cast<int>(FilterSize()));
+    }
+    ASSERT_LE(rate, 0.02);   // Must not be over 2%
+    if (rate > 0.0125) mediocre_filters++;  // Allowed, but not too often
+    else good_filters++;
+  }
+  if (kVerbose >= 1) {
+    fprintf(stderr, "Filters: %d good, %d mediocre\n",
+            good_filters, mediocre_filters);
+  }
+  ASSERT_LE(mediocre_filters, good_filters/5);
+}
+
+// Different bits-per-byte
+
+}  // namespace leveldb
+
+int main(int argc, char** argv) {
+  return leveldb::test::RunAllTests();
+}
diff --git a/src/leveldb/util/cache.cc b/src/leveldb/util/cache.cc
new file mode 100644
index 0000000000..24f1f63f4f
--- /dev/null
+++ b/src/leveldb/util/cache.cc
@@ -0,0 +1,328 @@
+// 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.
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "leveldb/cache.h"
+#include "port/port.h"
+#include "util/hash.h"
+#include "util/mutexlock.h"
+
+namespace leveldb {
+
+Cache::~Cache() {
+}
+
+namespace {
+
+// LRU cache implementation
+
+// An entry is a variable length heap-allocated structure.  Entries
+// are kept in a circular doubly linked list ordered by access time.
+struct LRUHandle {
+  void* value;
+  void (*deleter)(const Slice&, void* value);
+  LRUHandle* next_hash;
+  LRUHandle* next;
+  LRUHandle* prev;
+  size_t charge;      // TODO(opt): Only allow uint32_t?
+  size_t key_length;
+  uint32_t refs;
+  uint32_t hash;      // Hash of key(); used for fast sharding and comparisons
+  char key_data[1];   // Beginning of key
+
+  Slice key() const {
+    // For cheaper lookups, we allow a temporary Handle object
+    // to store a pointer to a key in "value".
+    if (next == this) {
+      return *(reinterpret_cast<Slice*>(value));
+    } else {
+      return Slice(key_data, key_length);
+    }
+  }
+};
+
+// We provide our own simple hash table since it removes a whole bunch
+// of porting hacks and is also faster than some of the built-in hash
+// table implementations in some of the compiler/runtime combinations
+// we have tested.  E.g., readrandom speeds up by ~5% over the g++
+// 4.4.3's builtin hashtable.
+class HandleTable {
+ public:
+  HandleTable() : length_(0), elems_(0), list_(NULL) { Resize(); }
+  ~HandleTable() { delete[] list_; }
+
+  LRUHandle* Lookup(const Slice& key, uint32_t hash) {
+    return *FindPointer(key, hash);
+  }
+
+  LRUHandle* Insert(LRUHandle* h) {
+    LRUHandle** ptr = FindPointer(h->key(), h->hash);
+    LRUHandle* old = *ptr;
+    h->next_hash = (old == NULL ? NULL : old->next_hash);
+    *ptr = h;
+    if (old == NULL) {
+      ++elems_;
+      if (elems_ > length_) {
+        // Since each cache entry is fairly large, we aim for a small
+        // average linked list length (<= 1).
+        Resize();
+      }
+    }
+    return old;
+  }
+
+  LRUHandle* Remove(const Slice& key, uint32_t hash) {
+    LRUHandle** ptr = FindPointer(key, hash);
+    LRUHandle* result = *ptr;
+    if (result != NULL) {
+      *ptr = result->next_hash;
+      --elems_;
+    }
+    return result;
+  }
+
+ private:
+  // The table consists of an array of buckets where each bucket is
+  // a linked list of cache entries that hash into the bucket.
+  uint32_t length_;
+  uint32_t elems_;
+  LRUHandle** list_;
+
+  // Return a pointer to slot that points to a cache entry that
+  // matches key/hash.  If there is no such cache entry, return a
+  // pointer to the trailing slot in the corresponding linked list.
+  LRUHandle** FindPointer(const Slice& key, uint32_t hash) {
+    LRUHandle** ptr = &list_[hash & (length_ - 1)];
+    while (*ptr != NULL &&
+           ((*ptr)->hash != hash || key != (*ptr)->key())) {
+      ptr = &(*ptr)->next_hash;
+    }
+    return ptr;
+  }
+
+  void Resize() {
+    uint32_t new_length = 4;
+    while (new_length < elems_) {
+      new_length *= 2;
+    }
+    LRUHandle** new_list = new LRUHandle*[new_length];
+    memset(new_list, 0, sizeof(new_list[0]) * new_length);
+    uint32_t count = 0;
+    for (uint32_t i = 0; i < length_; i++) {
+      LRUHandle* h = list_[i];
+      while (h != NULL) {
+        LRUHandle* next = h->next_hash;
+        Slice key = h->key();
+        uint32_t hash = h->hash;
+        LRUHandle** ptr = &new_list[hash & (new_length - 1)];
+        h->next_hash = *ptr;
+        *ptr = h;
+        h = next;
+        count++;
+      }
+    }
+    assert(elems_ == count);
+    delete[] list_;
+    list_ = new_list;
+    length_ = new_length;
+  }
+};
+
+// A single shard of sharded cache.
+class LRUCache {
+ public:
+  LRUCache();
+  ~LRUCache();
+
+  // Separate from constructor so caller can easily make an array of LRUCache
+  void SetCapacity(size_t capacity) { capacity_ = capacity; }
+
+  // Like Cache methods, but with an extra "hash" parameter.
+  Cache::Handle* Insert(const Slice& key, uint32_t hash,
+                        void* value, size_t charge,
+                        void (*deleter)(const Slice& key, void* value));
+  Cache::Handle* Lookup(const Slice& key, uint32_t hash);
+  void Release(Cache::Handle* handle);
+  void Erase(const Slice& key, uint32_t hash);
+
+ private:
+  void LRU_Remove(LRUHandle* e);
+  void LRU_Append(LRUHandle* e);
+  void Unref(LRUHandle* e);
+
+  // Initialized before use.
+  size_t capacity_;
+
+  // mutex_ protects the following state.
+  port::Mutex mutex_;
+  size_t usage_;
+  uint64_t last_id_;
+
+  // Dummy head of LRU list.
+  // lru.prev is newest entry, lru.next is oldest entry.
+  LRUHandle lru_;
+
+  HandleTable table_;
+};
+
+LRUCache::LRUCache()
+    : usage_(0),
+      last_id_(0) {
+  // Make empty circular linked list
+  lru_.next = &lru_;
+  lru_.prev = &lru_;
+}
+
+LRUCache::~LRUCache() {
+  for (LRUHandle* e = lru_.next; e != &lru_; ) {
+    LRUHandle* next = e->next;
+    assert(e->refs == 1);  // Error if caller has an unreleased handle
+    Unref(e);
+    e = next;
+  }
+}
+
+void LRUCache::Unref(LRUHandle* e) {
+  assert(e->refs > 0);
+  e->refs--;
+  if (e->refs <= 0) {
+    usage_ -= e->charge;
+    (*e->deleter)(e->key(), e->value);
+    free(e);
+  }
+}
+
+void LRUCache::LRU_Remove(LRUHandle* e) {
+  e->next->prev = e->prev;
+  e->prev->next = e->next;
+}
+
+void LRUCache::LRU_Append(LRUHandle* e) {
+  // Make "e" newest entry by inserting just before lru_
+  e->next = &lru_;
+  e->prev = lru_.prev;
+  e->prev->next = e;
+  e->next->prev = e;
+}
+
+Cache::Handle* LRUCache::Lookup(const Slice& key, uint32_t hash) {
+  MutexLock l(&mutex_);
+  LRUHandle* e = table_.Lookup(key, hash);
+  if (e != NULL) {
+    e->refs++;
+    LRU_Remove(e);
+    LRU_Append(e);
+  }
+  return reinterpret_cast<Cache::Handle*>(e);
+}
+
+void LRUCache::Release(Cache::Handle* handle) {
+  MutexLock l(&mutex_);
+  Unref(reinterpret_cast<LRUHandle*>(handle));
+}
+
+Cache::Handle* LRUCache::Insert(
+    const Slice& key, uint32_t hash, void* value, size_t charge,
+    void (*deleter)(const Slice& key, void* value)) {
+  MutexLock l(&mutex_);
+
+  LRUHandle* e = reinterpret_cast<LRUHandle*>(
+      malloc(sizeof(LRUHandle)-1 + key.size()));
+  e->value = value;
+  e->deleter = deleter;
+  e->charge = charge;
+  e->key_length = key.size();
+  e->hash = hash;
+  e->refs = 2;  // One from LRUCache, one for the returned handle
+  memcpy(e->key_data, key.data(), key.size());
+  LRU_Append(e);
+  usage_ += charge;
+
+  LRUHandle* old = table_.Insert(e);
+  if (old != NULL) {
+    LRU_Remove(old);
+    Unref(old);
+  }
+
+  while (usage_ > capacity_ && lru_.next != &lru_) {
+    LRUHandle* old = lru_.next;
+    LRU_Remove(old);
+    table_.Remove(old->key(), old->hash);
+    Unref(old);
+  }
+
+  return reinterpret_cast<Cache::Handle*>(e);
+}
+
+void LRUCache::Erase(const Slice& key, uint32_t hash) {
+  MutexLock l(&mutex_);
+  LRUHandle* e = table_.Remove(key, hash);
+  if (e != NULL) {
+    LRU_Remove(e);
+    Unref(e);
+  }
+}
+
+static const int kNumShardBits = 4;
+static const int kNumShards = 1 << kNumShardBits;
+
+class ShardedLRUCache : public Cache {
+ private:
+  LRUCache shard_[kNumShards];
+  port::Mutex id_mutex_;
+  uint64_t last_id_;
+
+  static inline uint32_t HashSlice(const Slice& s) {
+    return Hash(s.data(), s.size(), 0);
+  }
+
+  static uint32_t Shard(uint32_t hash) {
+    return hash >> (32 - kNumShardBits);
+  }
+
+ public:
+  explicit ShardedLRUCache(size_t capacity)
+      : last_id_(0) {
+    const size_t per_shard = (capacity + (kNumShards - 1)) / kNumShards;
+    for (int s = 0; s < kNumShards; s++) {
+      shard_[s].SetCapacity(per_shard);
+    }
+  }
+  virtual ~ShardedLRUCache() { }
+  virtual Handle* Insert(const Slice& key, void* value, size_t charge,
+                         void (*deleter)(const Slice& key, void* value)) {
+    const uint32_t hash = HashSlice(key);
+    return shard_[Shard(hash)].Insert(key, hash, value, charge, deleter);
+  }
+  virtual Handle* Lookup(const Slice& key) {
+    const uint32_t hash = HashSlice(key);
+    return shard_[Shard(hash)].Lookup(key, hash);
+  }
+  virtual void Release(Handle* handle) {
+    LRUHandle* h = reinterpret_cast<LRUHandle*>(handle);
+    shard_[Shard(h->hash)].Release(handle);
+  }
+  virtual void Erase(const Slice& key) {
+    const uint32_t hash = HashSlice(key);
+    shard_[Shard(hash)].Erase(key, hash);
+  }
+  virtual void* Value(Handle* handle) {
+    return reinterpret_cast<LRUHandle*>(handle)->value;
+  }
+  virtual uint64_t NewId() {
+    MutexLock l(&id_mutex_);
+    return ++(last_id_);
+  }
+};
+
+}  // end anonymous namespace
+
+Cache* NewLRUCache(size_t capacity) {
+  return new ShardedLRUCache(capacity);
+}
+
+}  // namespace leveldb
diff --git a/src/leveldb/util/cache_test.cc b/src/leveldb/util/cache_test.cc
new file mode 100644
index 0000000000..43716715a8
--- /dev/null
+++ b/src/leveldb/util/cache_test.cc
@@ -0,0 +1,186 @@
+// 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.
+
+#include "leveldb/cache.h"
+
+#include <vector>
+#include "util/coding.h"
+#include "util/testharness.h"
+
+namespace leveldb {
+
+// Conversions between numeric keys/values and the types expected by Cache.
+static std::string EncodeKey(int k) {
+  std::string result;
+  PutFixed32(&result, k);
+  return result;
+}
+static int DecodeKey(const Slice& k) {
+  assert(k.size() == 4);
+  return DecodeFixed32(k.data());
+}
+static void* EncodeValue(uintptr_t v) { return reinterpret_cast<void*>(v); }
+static int DecodeValue(void* v) { return reinterpret_cast<uintptr_t>(v); }
+
+class CacheTest {
+ public:
+  static CacheTest* current_;
+
+  static void Deleter(const Slice& key, void* v) {
+    current_->deleted_keys_.push_back(DecodeKey(key));
+    current_->deleted_values_.push_back(DecodeValue(v));
+  }
+
+  static const int kCacheSize = 1000;
+  std::vector<int> deleted_keys_;
+  std::vector<int> deleted_values_;
+  Cache* cache_;
+
+  CacheTest() : cache_(NewLRUCache(kCacheSize)) {
+    current_ = this;
+  }
+
+  ~CacheTest() {
+    delete cache_;
+  }
+
+  int Lookup(int key) {
+    Cache::Handle* handle = cache_->Lookup(EncodeKey(key));
+    const int r = (handle == NULL) ? -1 : DecodeValue(cache_->Value(handle));
+    if (handle != NULL) {
+      cache_->Release(handle);
+    }
+    return r;
+  }
+
+  void Insert(int key, int value, int charge = 1) {
+    cache_->Release(cache_->Insert(EncodeKey(key), EncodeValue(value), charge,
+                                   &CacheTest::Deleter));
+  }
+
+  void Erase(int key) {
+    cache_->Erase(EncodeKey(key));
+  }
+};
+CacheTest* CacheTest::current_;
+
+TEST(CacheTest, HitAndMiss) {
+  ASSERT_EQ(-1, Lookup(100));
+
+  Insert(100, 101);
+  ASSERT_EQ(101, Lookup(100));
+  ASSERT_EQ(-1,  Lookup(200));
+  ASSERT_EQ(-1,  Lookup(300));
+
+  Insert(200, 201);
+  ASSERT_EQ(101, Lookup(100));
+  ASSERT_EQ(201, Lookup(200));
+  ASSERT_EQ(-1,  Lookup(300));
+
+  Insert(100, 102);
+  ASSERT_EQ(102, Lookup(100));
+  ASSERT_EQ(201, Lookup(200));
+  ASSERT_EQ(-1,  Lookup(300));
+
+  ASSERT_EQ(1, deleted_keys_.size());
+  ASSERT_EQ(100, deleted_keys_[0]);
+  ASSERT_EQ(101, deleted_values_[0]);
+}
+
+TEST(CacheTest, Erase) {
+  Erase(200);
+  ASSERT_EQ(0, deleted_keys_.size());
+
+  Insert(100, 101);
+  Insert(200, 201);
+  Erase(100);
+  ASSERT_EQ(-1,  Lookup(100));
+  ASSERT_EQ(201, Lookup(200));
+  ASSERT_EQ(1, deleted_keys_.size());
+  ASSERT_EQ(100, deleted_keys_[0]);
+  ASSERT_EQ(101, deleted_values_[0]);
+
+  Erase(100);
+  ASSERT_EQ(-1,  Lookup(100));
+  ASSERT_EQ(201, Lookup(200));
+  ASSERT_EQ(1, deleted_keys_.size());
+}
+
+TEST(CacheTest, EntriesArePinned) {
+  Insert(100, 101);
+  Cache::Handle* h1 = cache_->Lookup(EncodeKey(100));
+  ASSERT_EQ(101, DecodeValue(cache_->Value(h1)));
+
+  Insert(100, 102);
+  Cache::Handle* h2 = cache_->Lookup(EncodeKey(100));
+  ASSERT_EQ(102, DecodeValue(cache_->Value(h2)));
+  ASSERT_EQ(0, deleted_keys_.size());
+
+  cache_->Release(h1);
+  ASSERT_EQ(1, deleted_keys_.size());
+  ASSERT_EQ(100, deleted_keys_[0]);
+  ASSERT_EQ(101, deleted_values_[0]);
+
+  Erase(100);
+  ASSERT_EQ(-1, Lookup(100));
+  ASSERT_EQ(1, deleted_keys_.size());
+
+  cache_->Release(h2);
+  ASSERT_EQ(2, deleted_keys_.size());
+  ASSERT_EQ(100, deleted_keys_[1]);
+  ASSERT_EQ(102, deleted_values_[1]);
+}
+
+TEST(CacheTest, EvictionPolicy) {
+  Insert(100, 101);
+  Insert(200, 201);
+
+  // Frequently used entry must be kept around
+  for (int i = 0; i < kCacheSize + 100; i++) {
+    Insert(1000+i, 2000+i);
+    ASSERT_EQ(2000+i, Lookup(1000+i));
+    ASSERT_EQ(101, Lookup(100));
+  }
+  ASSERT_EQ(101, Lookup(100));
+  ASSERT_EQ(-1, Lookup(200));
+}
+
+TEST(CacheTest, HeavyEntries) {
+  // Add a bunch of light and heavy entries and then count the combined
+  // size of items still in the cache, which must be approximately the
+  // same as the total capacity.
+  const int kLight = 1;
+  const int kHeavy = 10;
+  int added = 0;
+  int index = 0;
+  while (added < 2*kCacheSize) {
+    const int weight = (index & 1) ? kLight : kHeavy;
+    Insert(index, 1000+index, weight);
+    added += weight;
+    index++;
+  }
+
+  int cached_weight = 0;
+  for (int i = 0; i < index; i++) {
+    const int weight = (i & 1 ? kLight : kHeavy);
+    int r = Lookup(i);
+    if (r >= 0) {
+      cached_weight += weight;
+      ASSERT_EQ(1000+i, r);
+    }
+  }
+  ASSERT_LE(cached_weight, kCacheSize + kCacheSize/10);
+}
+
+TEST(CacheTest, NewId) {
+  uint64_t a = cache_->NewId();
+  uint64_t b = cache_->NewId();
+  ASSERT_NE(a, b);
+}
+
+}  // namespace leveldb
+
+int main(int argc, char** argv) {
+  return leveldb::test::RunAllTests();
+}
diff --git a/src/leveldb/util/coding.cc b/src/leveldb/util/coding.cc
new file mode 100644
index 0000000000..dbd7a6545c
--- /dev/null
+++ b/src/leveldb/util/coding.cc
@@ -0,0 +1,194 @@
+// 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.
+
+#include "util/coding.h"
+
+namespace leveldb {
+
+void EncodeFixed32(char* buf, uint32_t value) {
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+  memcpy(buf, &value, sizeof(value));
+#else
+  buf[0] = value & 0xff;
+  buf[1] = (value >> 8) & 0xff;
+  buf[2] = (value >> 16) & 0xff;
+  buf[3] = (value >> 24) & 0xff;
+#endif
+}
+
+void EncodeFixed64(char* buf, uint64_t value) {
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+  memcpy(buf, &value, sizeof(value));
+#else
+  buf[0] = value & 0xff;
+  buf[1] = (value >> 8) & 0xff;
+  buf[2] = (value >> 16) & 0xff;
+  buf[3] = (value >> 24) & 0xff;
+  buf[4] = (value >> 32) & 0xff;
+  buf[5] = (value >> 40) & 0xff;
+  buf[6] = (value >> 48) & 0xff;
+  buf[7] = (value >> 56) & 0xff;
+#endif
+}
+
+void PutFixed32(std::string* dst, uint32_t value) {
+  char buf[sizeof(value)];
+  EncodeFixed32(buf, value);
+  dst->append(buf, sizeof(buf));
+}
+
+void PutFixed64(std::string* dst, uint64_t value) {
+  char buf[sizeof(value)];
+  EncodeFixed64(buf, value);
+  dst->append(buf, sizeof(buf));
+}
+
+char* EncodeVarint32(char* dst, uint32_t v) {
+  // Operate on characters as unsigneds
+  unsigned char* ptr = reinterpret_cast<unsigned char*>(dst);
+  static const int B = 128;
+  if (v < (1<<7)) {
+    *(ptr++) = v;
+  } else if (v < (1<<14)) {
+    *(ptr++) = v | B;
+    *(ptr++) = v>>7;
+  } else if (v < (1<<21)) {
+    *(ptr++) = v | B;
+    *(ptr++) = (v>>7) | B;
+    *(ptr++) = v>>14;
+  } else if (v < (1<<28)) {
+    *(ptr++) = v | B;
+    *(ptr++) = (v>>7) | B;
+    *(ptr++) = (v>>14) | B;
+    *(ptr++) = v>>21;
+  } else {
+    *(ptr++) = v | B;
+    *(ptr++) = (v>>7) | B;
+    *(ptr++) = (v>>14) | B;
+    *(ptr++) = (v>>21) | B;
+    *(ptr++) = v>>28;
+  }
+  return reinterpret_cast<char*>(ptr);
+}
+
+void PutVarint32(std::string* dst, uint32_t v) {
+  char buf[5];
+  char* ptr = EncodeVarint32(buf, v);
+  dst->append(buf, ptr - buf);
+}
+
+char* EncodeVarint64(char* dst, uint64_t v) {
+  static const int B = 128;
+  unsigned char* ptr = reinterpret_cast<unsigned char*>(dst);
+  while (v >= B) {
+    *(ptr++) = (v & (B-1)) | B;
+    v >>= 7;
+  }
+  *(ptr++) = static_cast<unsigned char>(v);
+  return reinterpret_cast<char*>(ptr);
+}
+
+void PutVarint64(std::string* dst, uint64_t v) {
+  char buf[10];
+  char* ptr = EncodeVarint64(buf, v);
+  dst->append(buf, ptr - buf);
+}
+
+void PutLengthPrefixedSlice(std::string* dst, const Slice& value) {
+  PutVarint32(dst, value.size());
+  dst->append(value.data(), value.size());
+}
+
+int VarintLength(uint64_t v) {
+  int len = 1;
+  while (v >= 128) {
+    v >>= 7;
+    len++;
+  }
+  return len;
+}
+
+const char* GetVarint32PtrFallback(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 unsigned char*>(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 NULL;
+}
+
+bool GetVarint32(Slice* input, uint32_t* value) {
+  const char* p = input->data();
+  const char* limit = p + input->size();
+  const char* q = GetVarint32Ptr(p, limit, value);
+  if (q == NULL) {
+    return false;
+  } else {
+    *input = Slice(q, limit - q);
+    return true;
+  }
+}
+
+const char* GetVarint64Ptr(const char* p, const char* limit, uint64_t* value) {
+  uint64_t result = 0;
+  for (uint32_t shift = 0; shift <= 63 && p < limit; shift += 7) {
+    uint64_t byte = *(reinterpret_cast<const unsigned char*>(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 NULL;
+}
+
+bool GetVarint64(Slice* input, uint64_t* value) {
+  const char* p = input->data();
+  const char* limit = p + input->size();
+  const char* q = GetVarint64Ptr(p, limit, value);
+  if (q == NULL) {
+    return false;
+  } else {
+    *input = Slice(q, limit - q);
+    return true;
+  }
+}
+
+const char* GetLengthPrefixedSlice(const char* p, const char* limit,
+                                   Slice* result) {
+  uint32_t len;
+  p = GetVarint32Ptr(p, limit, &len);
+  if (p == NULL) return NULL;
+  if (p + len > limit) return NULL;
+  *result = Slice(p, len);
+  return p + len;
+}
+
+bool GetLengthPrefixedSlice(Slice* input, Slice* result) {
+  uint32_t len;
+  if (GetVarint32(input, &len) &&
+      input->size() >= len) {
+    *result = Slice(input->data(), len);
+    input->remove_prefix(len);
+    return true;
+  } else {
+    return false;
+  }
+}
+
+}  // namespace leveldb
diff --git a/src/leveldb/util/coding.h b/src/leveldb/util/coding.h
new file mode 100644
index 0000000000..3993c4a755
--- /dev/null
+++ b/src/leveldb/util/coding.h
@@ -0,0 +1,104 @@
+// 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.
+//
+// Endian-neutral encoding:
+// * Fixed-length numbers are encoded with least-significant byte first
+// * In addition we support variable length "varint" encoding
+// * Strings are encoded prefixed by their length in varint format
+
+#ifndef STORAGE_LEVELDB_UTIL_CODING_H_
+#define STORAGE_LEVELDB_UTIL_CODING_H_
+
+#include <stdint.h>
+#include <string.h>
+#include <string>
+#include "leveldb/slice.h"
+#include "port/port.h"
+
+namespace leveldb {
+
+// Standard Put... routines append to a string
+extern void PutFixed32(std::string* dst, uint32_t value);
+extern void PutFixed64(std::string* dst, uint64_t value);
+extern void PutVarint32(std::string* dst, uint32_t value);
+extern void PutVarint64(std::string* dst, uint64_t value);
+extern void PutLengthPrefixedSlice(std::string* dst, const Slice& value);
+
+// Standard Get... routines parse a value from the beginning of a Slice
+// and advance the slice past the parsed value.
+extern bool GetVarint32(Slice* input, uint32_t* value);
+extern bool GetVarint64(Slice* input, uint64_t* value);
+extern bool GetLengthPrefixedSlice(Slice* input, Slice* result);
+
+// Pointer-based variants of GetVarint...  These either store a value
+// in *v and return a pointer just past the parsed value, or return
+// NULL on error.  These routines only look at bytes in the range
+// [p..limit-1]
+extern const char* GetVarint32Ptr(const char* p,const char* limit, uint32_t* v);
+extern const char* GetVarint64Ptr(const char* p,const char* limit, uint64_t* v);
+
+// Returns the length of the varint32 or varint64 encoding of "v"
+extern int VarintLength(uint64_t v);
+
+// Lower-level versions of Put... that write directly into a character buffer
+// REQUIRES: dst has enough space for the value being written
+extern void EncodeFixed32(char* dst, uint32_t value);
+extern void EncodeFixed64(char* dst, uint64_t value);
+
+// Lower-level versions of Put... that write directly into a character buffer
+// and return a pointer just past the last byte written.
+// REQUIRES: dst has enough space for the value being written
+extern char* EncodeVarint32(char* dst, uint32_t value);
+extern char* EncodeVarint64(char* dst, uint64_t value);
+
+// Lower-level versions of Get... that read directly from a character buffer
+// without any bounds checking.
+
+inline uint32_t DecodeFixed32(const char* ptr) {
+  if (port::kLittleEndian) {
+    // Load the raw bytes
+    uint32_t result;
+    memcpy(&result, ptr, sizeof(result));  // gcc optimizes this to a plain load
+    return result;
+  } else {
+    return ((static_cast<uint32_t>(static_cast<unsigned char>(ptr[0])))
+        | (static_cast<uint32_t>(static_cast<unsigned char>(ptr[1])) << 8)
+        | (static_cast<uint32_t>(static_cast<unsigned char>(ptr[2])) << 16)
+        | (static_cast<uint32_t>(static_cast<unsigned char>(ptr[3])) << 24));
+  }
+}
+
+inline uint64_t DecodeFixed64(const char* ptr) {
+  if (port::kLittleEndian) {
+    // Load the raw bytes
+    uint64_t result;
+    memcpy(&result, ptr, sizeof(result));  // gcc optimizes this to a plain load
+    return result;
+  } else {
+    uint64_t lo = DecodeFixed32(ptr);
+    uint64_t hi = DecodeFixed32(ptr + 4);
+    return (hi << 32) | lo;
+  }
+}
+
+// Internal routine for use by fallback path of GetVarint32Ptr
+extern const char* GetVarint32PtrFallback(const char* p,
+                                          const char* limit,
+                                          uint32_t* value);
+inline const char* GetVarint32Ptr(const char* p,
+                                  const char* limit,
+                                  uint32_t* value) {
+  if (p < limit) {
+    uint32_t result = *(reinterpret_cast<const unsigned char*>(p));
+    if ((result & 128) == 0) {
+      *value = result;
+      return p + 1;
+    }
+  }
+  return GetVarint32PtrFallback(p, limit, value);
+}
+
+}  // namespace leveldb
+
+#endif  // STORAGE_LEVELDB_UTIL_CODING_H_
diff --git a/src/leveldb/util/coding_test.cc b/src/leveldb/util/coding_test.cc
new file mode 100644
index 0000000000..2c52b17b60
--- /dev/null
+++ b/src/leveldb/util/coding_test.cc
@@ -0,0 +1,196 @@
+// 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.
+
+#include "util/coding.h"
+
+#include "util/testharness.h"
+
+namespace leveldb {
+
+class Coding { };
+
+TEST(Coding, Fixed32) {
+  std::string s;
+  for (uint32_t v = 0; v < 100000; v++) {
+    PutFixed32(&s, v);
+  }
+
+  const char* p = s.data();
+  for (uint32_t v = 0; v < 100000; v++) {
+    uint32_t actual = DecodeFixed32(p);
+    ASSERT_EQ(v, actual);
+    p += sizeof(uint32_t);
+  }
+}
+
+TEST(Coding, Fixed64) {
+  std::string s;
+  for (int power = 0; power <= 63; power++) {
+    uint64_t v = static_cast<uint64_t>(1) << power;
+    PutFixed64(&s, v - 1);
+    PutFixed64(&s, v + 0);
+    PutFixed64(&s, v + 1);
+  }
+
+  const char* p = s.data();
+  for (int power = 0; power <= 63; power++) {
+    uint64_t v = static_cast<uint64_t>(1) << power;
+    uint64_t actual;
+    actual = DecodeFixed64(p);
+    ASSERT_EQ(v-1, actual);
+    p += sizeof(uint64_t);
+
+    actual = DecodeFixed64(p);
+    ASSERT_EQ(v+0, actual);
+    p += sizeof(uint64_t);
+
+    actual = DecodeFixed64(p);
+    ASSERT_EQ(v+1, actual);
+    p += sizeof(uint64_t);
+  }
+}
+
+// Test that encoding routines generate little-endian encodings
+TEST(Coding, EncodingOutput) {
+  std::string dst;
+  PutFixed32(&dst, 0x04030201);
+  ASSERT_EQ(4, dst.size());
+  ASSERT_EQ(0x01, static_cast<int>(dst[0]));
+  ASSERT_EQ(0x02, static_cast<int>(dst[1]));
+  ASSERT_EQ(0x03, static_cast<int>(dst[2]));
+  ASSERT_EQ(0x04, static_cast<int>(dst[3]));
+
+  dst.clear();
+  PutFixed64(&dst, 0x0807060504030201ull);
+  ASSERT_EQ(8, dst.size());
+  ASSERT_EQ(0x01, static_cast<int>(dst[0]));
+  ASSERT_EQ(0x02, static_cast<int>(dst[1]));
+  ASSERT_EQ(0x03, static_cast<int>(dst[2]));
+  ASSERT_EQ(0x04, static_cast<int>(dst[3]));
+  ASSERT_EQ(0x05, static_cast<int>(dst[4]));
+  ASSERT_EQ(0x06, static_cast<int>(dst[5]));
+  ASSERT_EQ(0x07, static_cast<int>(dst[6]));
+  ASSERT_EQ(0x08, static_cast<int>(dst[7]));
+}
+
+TEST(Coding, Varint32) {
+  std::string s;
+  for (uint32_t i = 0; i < (32 * 32); i++) {
+    uint32_t v = (i / 32) << (i % 32);
+    PutVarint32(&s, v);
+  }
+
+  const char* p = s.data();
+  const char* limit = p + s.size();
+  for (uint32_t i = 0; i < (32 * 32); i++) {
+    uint32_t expected = (i / 32) << (i % 32);
+    uint32_t actual;
+    const char* start = p;
+    p = GetVarint32Ptr(p, limit, &actual);
+    ASSERT_TRUE(p != NULL);
+    ASSERT_EQ(expected, actual);
+    ASSERT_EQ(VarintLength(actual), p - start);
+  }
+  ASSERT_EQ(p, s.data() + s.size());
+}
+
+TEST(Coding, Varint64) {
+  // Construct the list of values to check
+  std::vector<uint64_t> values;
+  // Some special values
+  values.push_back(0);
+  values.push_back(100);
+  values.push_back(~static_cast<uint64_t>(0));
+  values.push_back(~static_cast<uint64_t>(0) - 1);
+  for (uint32_t k = 0; k < 64; k++) {
+    // Test values near powers of two
+    const uint64_t power = 1ull << k;
+    values.push_back(power);
+    values.push_back(power-1);
+    values.push_back(power+1);
+  };
+
+  std::string s;
+  for (int i = 0; i < values.size(); i++) {
+    PutVarint64(&s, values[i]);
+  }
+
+  const char* p = s.data();
+  const char* limit = p + s.size();
+  for (int i = 0; i < values.size(); i++) {
+    ASSERT_TRUE(p < limit);
+    uint64_t actual;
+    const char* start = p;
+    p = GetVarint64Ptr(p, limit, &actual);
+    ASSERT_TRUE(p != NULL);
+    ASSERT_EQ(values[i], actual);
+    ASSERT_EQ(VarintLength(actual), p - start);
+  }
+  ASSERT_EQ(p, limit);
+
+}
+
+TEST(Coding, Varint32Overflow) {
+  uint32_t result;
+  std::string input("\x81\x82\x83\x84\x85\x11");
+  ASSERT_TRUE(GetVarint32Ptr(input.data(), input.data() + input.size(), &result)
+              == NULL);
+}
+
+TEST(Coding, Varint32Truncation) {
+  uint32_t large_value = (1u << 31) + 100;
+  std::string s;
+  PutVarint32(&s, large_value);
+  uint32_t result;
+  for (int len = 0; len < s.size() - 1; len++) {
+    ASSERT_TRUE(GetVarint32Ptr(s.data(), s.data() + len, &result) == NULL);
+  }
+  ASSERT_TRUE(GetVarint32Ptr(s.data(), s.data() + s.size(), &result) != NULL);
+  ASSERT_EQ(large_value, result);
+}
+
+TEST(Coding, Varint64Overflow) {
+  uint64_t result;
+  std::string input("\x81\x82\x83\x84\x85\x81\x82\x83\x84\x85\x11");
+  ASSERT_TRUE(GetVarint64Ptr(input.data(), input.data() + input.size(), &result)
+              == NULL);
+}
+
+TEST(Coding, Varint64Truncation) {
+  uint64_t large_value = (1ull << 63) + 100ull;
+  std::string s;
+  PutVarint64(&s, large_value);
+  uint64_t result;
+  for (int len = 0; len < s.size() - 1; len++) {
+    ASSERT_TRUE(GetVarint64Ptr(s.data(), s.data() + len, &result) == NULL);
+  }
+  ASSERT_TRUE(GetVarint64Ptr(s.data(), s.data() + s.size(), &result) != NULL);
+  ASSERT_EQ(large_value, result);
+}
+
+TEST(Coding, Strings) {
+  std::string s;
+  PutLengthPrefixedSlice(&s, Slice(""));
+  PutLengthPrefixedSlice(&s, Slice("foo"));
+  PutLengthPrefixedSlice(&s, Slice("bar"));
+  PutLengthPrefixedSlice(&s, Slice(std::string(200, 'x')));
+
+  Slice input(s);
+  Slice v;
+  ASSERT_TRUE(GetLengthPrefixedSlice(&input, &v));
+  ASSERT_EQ("", v.ToString());
+  ASSERT_TRUE(GetLengthPrefixedSlice(&input, &v));
+  ASSERT_EQ("foo", v.ToString());
+  ASSERT_TRUE(GetLengthPrefixedSlice(&input, &v));
+  ASSERT_EQ("bar", v.ToString());
+  ASSERT_TRUE(GetLengthPrefixedSlice(&input, &v));
+  ASSERT_EQ(std::string(200, 'x'), v.ToString());
+  ASSERT_EQ("", input.ToString());
+}
+
+}  // namespace leveldb
+
+int main(int argc, char** argv) {
+  return leveldb::test::RunAllTests();
+}
diff --git a/src/leveldb/util/comparator.cc b/src/leveldb/util/comparator.cc
new file mode 100644
index 0000000000..4b7b5724ef
--- /dev/null
+++ b/src/leveldb/util/comparator.cc
@@ -0,0 +1,81 @@
+// 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.
+
+#include <algorithm>
+#include <stdint.h>
+#include "leveldb/comparator.h"
+#include "leveldb/slice.h"
+#include "port/port.h"
+#include "util/logging.h"
+
+namespace leveldb {
+
+Comparator::~Comparator() { }
+
+namespace {
+class BytewiseComparatorImpl : public Comparator {
+ public:
+  BytewiseComparatorImpl() { }
+
+  virtual const char* Name() const {
+    return "leveldb.BytewiseComparator";
+  }
+
+  virtual int Compare(const Slice& a, const Slice& b) const {
+    return a.compare(b);
+  }
+
+  virtual void FindShortestSeparator(
+      std::string* start,
+      const Slice& limit) const {
+    // 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);
+      }
+    }
+  }
+
+  virtual void FindShortSuccessor(std::string* key) const {
+    // 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
+
+static port::OnceType once = LEVELDB_ONCE_INIT;
+static const Comparator* bytewise;
+
+static void InitModule() {
+  bytewise = new BytewiseComparatorImpl;
+}
+
+const Comparator* BytewiseComparator() {
+  port::InitOnce(&once, InitModule);
+  return bytewise;
+}
+
+}  // namespace leveldb
diff --git a/src/leveldb/util/crc32c.cc b/src/leveldb/util/crc32c.cc
new file mode 100644
index 0000000000..6db9e77077
--- /dev/null
+++ b/src/leveldb/util/crc32c.cc
@@ -0,0 +1,332 @@
+// 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.
+//
+// A portable implementation of crc32c, optimized to handle
+// four bytes at a time.
+
+#include "util/crc32c.h"
+
+#include <stdint.h>
+#include "util/coding.h"
+
+namespace leveldb {
+namespace crc32c {
+
+static const uint32_t table0_[256] = {
+  0x00000000, 0xf26b8303, 0xe13b70f7, 0x1350f3f4,
+  0xc79a971f, 0x35f1141c, 0x26a1e7e8, 0xd4ca64eb,
+  0x8ad958cf, 0x78b2dbcc, 0x6be22838, 0x9989ab3b,
+  0x4d43cfd0, 0xbf284cd3, 0xac78bf27, 0x5e133c24,
+  0x105ec76f, 0xe235446c, 0xf165b798, 0x030e349b,
+  0xd7c45070, 0x25afd373, 0x36ff2087, 0xc494a384,
+  0x9a879fa0, 0x68ec1ca3, 0x7bbcef57, 0x89d76c54,
+  0x5d1d08bf, 0xaf768bbc, 0xbc267848, 0x4e4dfb4b,
+  0x20bd8ede, 0xd2d60ddd, 0xc186fe29, 0x33ed7d2a,
+  0xe72719c1, 0x154c9ac2, 0x061c6936, 0xf477ea35,
+  0xaa64d611, 0x580f5512, 0x4b5fa6e6, 0xb93425e5,
+  0x6dfe410e, 0x9f95c20d, 0x8cc531f9, 0x7eaeb2fa,
+  0x30e349b1, 0xc288cab2, 0xd1d83946, 0x23b3ba45,
+  0xf779deae, 0x05125dad, 0x1642ae59, 0xe4292d5a,
+  0xba3a117e, 0x4851927d, 0x5b016189, 0xa96ae28a,
+  0x7da08661, 0x8fcb0562, 0x9c9bf696, 0x6ef07595,
+  0x417b1dbc, 0xb3109ebf, 0xa0406d4b, 0x522bee48,
+  0x86e18aa3, 0x748a09a0, 0x67dafa54, 0x95b17957,
+  0xcba24573, 0x39c9c670, 0x2a993584, 0xd8f2b687,
+  0x0c38d26c, 0xfe53516f, 0xed03a29b, 0x1f682198,
+  0x5125dad3, 0xa34e59d0, 0xb01eaa24, 0x42752927,
+  0x96bf4dcc, 0x64d4cecf, 0x77843d3b, 0x85efbe38,
+  0xdbfc821c, 0x2997011f, 0x3ac7f2eb, 0xc8ac71e8,
+  0x1c661503, 0xee0d9600, 0xfd5d65f4, 0x0f36e6f7,
+  0x61c69362, 0x93ad1061, 0x80fde395, 0x72966096,
+  0xa65c047d, 0x5437877e, 0x4767748a, 0xb50cf789,
+  0xeb1fcbad, 0x197448ae, 0x0a24bb5a, 0xf84f3859,
+  0x2c855cb2, 0xdeeedfb1, 0xcdbe2c45, 0x3fd5af46,
+  0x7198540d, 0x83f3d70e, 0x90a324fa, 0x62c8a7f9,
+  0xb602c312, 0x44694011, 0x5739b3e5, 0xa55230e6,
+  0xfb410cc2, 0x092a8fc1, 0x1a7a7c35, 0xe811ff36,
+  0x3cdb9bdd, 0xceb018de, 0xdde0eb2a, 0x2f8b6829,
+  0x82f63b78, 0x709db87b, 0x63cd4b8f, 0x91a6c88c,
+  0x456cac67, 0xb7072f64, 0xa457dc90, 0x563c5f93,
+  0x082f63b7, 0xfa44e0b4, 0xe9141340, 0x1b7f9043,
+  0xcfb5f4a8, 0x3dde77ab, 0x2e8e845f, 0xdce5075c,
+  0x92a8fc17, 0x60c37f14, 0x73938ce0, 0x81f80fe3,
+  0x55326b08, 0xa759e80b, 0xb4091bff, 0x466298fc,
+  0x1871a4d8, 0xea1a27db, 0xf94ad42f, 0x0b21572c,
+  0xdfeb33c7, 0x2d80b0c4, 0x3ed04330, 0xccbbc033,
+  0xa24bb5a6, 0x502036a5, 0x4370c551, 0xb11b4652,
+  0x65d122b9, 0x97baa1ba, 0x84ea524e, 0x7681d14d,
+  0x2892ed69, 0xdaf96e6a, 0xc9a99d9e, 0x3bc21e9d,
+  0xef087a76, 0x1d63f975, 0x0e330a81, 0xfc588982,
+  0xb21572c9, 0x407ef1ca, 0x532e023e, 0xa145813d,
+  0x758fe5d6, 0x87e466d5, 0x94b49521, 0x66df1622,
+  0x38cc2a06, 0xcaa7a905, 0xd9f75af1, 0x2b9cd9f2,
+  0xff56bd19, 0x0d3d3e1a, 0x1e6dcdee, 0xec064eed,
+  0xc38d26c4, 0x31e6a5c7, 0x22b65633, 0xd0ddd530,
+  0x0417b1db, 0xf67c32d8, 0xe52cc12c, 0x1747422f,
+  0x49547e0b, 0xbb3ffd08, 0xa86f0efc, 0x5a048dff,
+  0x8ecee914, 0x7ca56a17, 0x6ff599e3, 0x9d9e1ae0,
+  0xd3d3e1ab, 0x21b862a8, 0x32e8915c, 0xc083125f,
+  0x144976b4, 0xe622f5b7, 0xf5720643, 0x07198540,
+  0x590ab964, 0xab613a67, 0xb831c993, 0x4a5a4a90,
+  0x9e902e7b, 0x6cfbad78, 0x7fab5e8c, 0x8dc0dd8f,
+  0xe330a81a, 0x115b2b19, 0x020bd8ed, 0xf0605bee,
+  0x24aa3f05, 0xd6c1bc06, 0xc5914ff2, 0x37faccf1,
+  0x69e9f0d5, 0x9b8273d6, 0x88d28022, 0x7ab90321,
+  0xae7367ca, 0x5c18e4c9, 0x4f48173d, 0xbd23943e,
+  0xf36e6f75, 0x0105ec76, 0x12551f82, 0xe03e9c81,
+  0x34f4f86a, 0xc69f7b69, 0xd5cf889d, 0x27a40b9e,
+  0x79b737ba, 0x8bdcb4b9, 0x988c474d, 0x6ae7c44e,
+  0xbe2da0a5, 0x4c4623a6, 0x5f16d052, 0xad7d5351
+};
+static const uint32_t table1_[256] = {
+  0x00000000, 0x13a29877, 0x274530ee, 0x34e7a899,
+  0x4e8a61dc, 0x5d28f9ab, 0x69cf5132, 0x7a6dc945,
+  0x9d14c3b8, 0x8eb65bcf, 0xba51f356, 0xa9f36b21,
+  0xd39ea264, 0xc03c3a13, 0xf4db928a, 0xe7790afd,
+  0x3fc5f181, 0x2c6769f6, 0x1880c16f, 0x0b225918,
+  0x714f905d, 0x62ed082a, 0x560aa0b3, 0x45a838c4,
+  0xa2d13239, 0xb173aa4e, 0x859402d7, 0x96369aa0,
+  0xec5b53e5, 0xfff9cb92, 0xcb1e630b, 0xd8bcfb7c,
+  0x7f8be302, 0x6c297b75, 0x58ced3ec, 0x4b6c4b9b,
+  0x310182de, 0x22a31aa9, 0x1644b230, 0x05e62a47,
+  0xe29f20ba, 0xf13db8cd, 0xc5da1054, 0xd6788823,
+  0xac154166, 0xbfb7d911, 0x8b507188, 0x98f2e9ff,
+  0x404e1283, 0x53ec8af4, 0x670b226d, 0x74a9ba1a,
+  0x0ec4735f, 0x1d66eb28, 0x298143b1, 0x3a23dbc6,
+  0xdd5ad13b, 0xcef8494c, 0xfa1fe1d5, 0xe9bd79a2,
+  0x93d0b0e7, 0x80722890, 0xb4958009, 0xa737187e,
+  0xff17c604, 0xecb55e73, 0xd852f6ea, 0xcbf06e9d,
+  0xb19da7d8, 0xa23f3faf, 0x96d89736, 0x857a0f41,
+  0x620305bc, 0x71a19dcb, 0x45463552, 0x56e4ad25,
+  0x2c896460, 0x3f2bfc17, 0x0bcc548e, 0x186eccf9,
+  0xc0d23785, 0xd370aff2, 0xe797076b, 0xf4359f1c,
+  0x8e585659, 0x9dface2e, 0xa91d66b7, 0xbabffec0,
+  0x5dc6f43d, 0x4e646c4a, 0x7a83c4d3, 0x69215ca4,
+  0x134c95e1, 0x00ee0d96, 0x3409a50f, 0x27ab3d78,
+  0x809c2506, 0x933ebd71, 0xa7d915e8, 0xb47b8d9f,
+  0xce1644da, 0xddb4dcad, 0xe9537434, 0xfaf1ec43,
+  0x1d88e6be, 0x0e2a7ec9, 0x3acdd650, 0x296f4e27,
+  0x53028762, 0x40a01f15, 0x7447b78c, 0x67e52ffb,
+  0xbf59d487, 0xacfb4cf0, 0x981ce469, 0x8bbe7c1e,
+  0xf1d3b55b, 0xe2712d2c, 0xd69685b5, 0xc5341dc2,
+  0x224d173f, 0x31ef8f48, 0x050827d1, 0x16aabfa6,
+  0x6cc776e3, 0x7f65ee94, 0x4b82460d, 0x5820de7a,
+  0xfbc3faf9, 0xe861628e, 0xdc86ca17, 0xcf245260,
+  0xb5499b25, 0xa6eb0352, 0x920cabcb, 0x81ae33bc,
+  0x66d73941, 0x7575a136, 0x419209af, 0x523091d8,
+  0x285d589d, 0x3bffc0ea, 0x0f186873, 0x1cbaf004,
+  0xc4060b78, 0xd7a4930f, 0xe3433b96, 0xf0e1a3e1,
+  0x8a8c6aa4, 0x992ef2d3, 0xadc95a4a, 0xbe6bc23d,
+  0x5912c8c0, 0x4ab050b7, 0x7e57f82e, 0x6df56059,
+  0x1798a91c, 0x043a316b, 0x30dd99f2, 0x237f0185,
+  0x844819fb, 0x97ea818c, 0xa30d2915, 0xb0afb162,
+  0xcac27827, 0xd960e050, 0xed8748c9, 0xfe25d0be,
+  0x195cda43, 0x0afe4234, 0x3e19eaad, 0x2dbb72da,
+  0x57d6bb9f, 0x447423e8, 0x70938b71, 0x63311306,
+  0xbb8de87a, 0xa82f700d, 0x9cc8d894, 0x8f6a40e3,
+  0xf50789a6, 0xe6a511d1, 0xd242b948, 0xc1e0213f,
+  0x26992bc2, 0x353bb3b5, 0x01dc1b2c, 0x127e835b,
+  0x68134a1e, 0x7bb1d269, 0x4f567af0, 0x5cf4e287,
+  0x04d43cfd, 0x1776a48a, 0x23910c13, 0x30339464,
+  0x4a5e5d21, 0x59fcc556, 0x6d1b6dcf, 0x7eb9f5b8,
+  0x99c0ff45, 0x8a626732, 0xbe85cfab, 0xad2757dc,
+  0xd74a9e99, 0xc4e806ee, 0xf00fae77, 0xe3ad3600,
+  0x3b11cd7c, 0x28b3550b, 0x1c54fd92, 0x0ff665e5,
+  0x759baca0, 0x663934d7, 0x52de9c4e, 0x417c0439,
+  0xa6050ec4, 0xb5a796b3, 0x81403e2a, 0x92e2a65d,
+  0xe88f6f18, 0xfb2df76f, 0xcfca5ff6, 0xdc68c781,
+  0x7b5fdfff, 0x68fd4788, 0x5c1aef11, 0x4fb87766,
+  0x35d5be23, 0x26772654, 0x12908ecd, 0x013216ba,
+  0xe64b1c47, 0xf5e98430, 0xc10e2ca9, 0xd2acb4de,
+  0xa8c17d9b, 0xbb63e5ec, 0x8f844d75, 0x9c26d502,
+  0x449a2e7e, 0x5738b609, 0x63df1e90, 0x707d86e7,
+  0x0a104fa2, 0x19b2d7d5, 0x2d557f4c, 0x3ef7e73b,
+  0xd98eedc6, 0xca2c75b1, 0xfecbdd28, 0xed69455f,
+  0x97048c1a, 0x84a6146d, 0xb041bcf4, 0xa3e32483
+};
+static const uint32_t table2_[256] = {
+  0x00000000, 0xa541927e, 0x4f6f520d, 0xea2ec073,
+  0x9edea41a, 0x3b9f3664, 0xd1b1f617, 0x74f06469,
+  0x38513ec5, 0x9d10acbb, 0x773e6cc8, 0xd27ffeb6,
+  0xa68f9adf, 0x03ce08a1, 0xe9e0c8d2, 0x4ca15aac,
+  0x70a27d8a, 0xd5e3eff4, 0x3fcd2f87, 0x9a8cbdf9,
+  0xee7cd990, 0x4b3d4bee, 0xa1138b9d, 0x045219e3,
+  0x48f3434f, 0xedb2d131, 0x079c1142, 0xa2dd833c,
+  0xd62de755, 0x736c752b, 0x9942b558, 0x3c032726,
+  0xe144fb14, 0x4405696a, 0xae2ba919, 0x0b6a3b67,
+  0x7f9a5f0e, 0xdadbcd70, 0x30f50d03, 0x95b49f7d,
+  0xd915c5d1, 0x7c5457af, 0x967a97dc, 0x333b05a2,
+  0x47cb61cb, 0xe28af3b5, 0x08a433c6, 0xade5a1b8,
+  0x91e6869e, 0x34a714e0, 0xde89d493, 0x7bc846ed,
+  0x0f382284, 0xaa79b0fa, 0x40577089, 0xe516e2f7,
+  0xa9b7b85b, 0x0cf62a25, 0xe6d8ea56, 0x43997828,
+  0x37691c41, 0x92288e3f, 0x78064e4c, 0xdd47dc32,
+  0xc76580d9, 0x622412a7, 0x880ad2d4, 0x2d4b40aa,
+  0x59bb24c3, 0xfcfab6bd, 0x16d476ce, 0xb395e4b0,
+  0xff34be1c, 0x5a752c62, 0xb05bec11, 0x151a7e6f,
+  0x61ea1a06, 0xc4ab8878, 0x2e85480b, 0x8bc4da75,
+  0xb7c7fd53, 0x12866f2d, 0xf8a8af5e, 0x5de93d20,
+  0x29195949, 0x8c58cb37, 0x66760b44, 0xc337993a,
+  0x8f96c396, 0x2ad751e8, 0xc0f9919b, 0x65b803e5,
+  0x1148678c, 0xb409f5f2, 0x5e273581, 0xfb66a7ff,
+  0x26217bcd, 0x8360e9b3, 0x694e29c0, 0xcc0fbbbe,
+  0xb8ffdfd7, 0x1dbe4da9, 0xf7908dda, 0x52d11fa4,
+  0x1e704508, 0xbb31d776, 0x511f1705, 0xf45e857b,
+  0x80aee112, 0x25ef736c, 0xcfc1b31f, 0x6a802161,
+  0x56830647, 0xf3c29439, 0x19ec544a, 0xbcadc634,
+  0xc85da25d, 0x6d1c3023, 0x8732f050, 0x2273622e,
+  0x6ed23882, 0xcb93aafc, 0x21bd6a8f, 0x84fcf8f1,
+  0xf00c9c98, 0x554d0ee6, 0xbf63ce95, 0x1a225ceb,
+  0x8b277743, 0x2e66e53d, 0xc448254e, 0x6109b730,
+  0x15f9d359, 0xb0b84127, 0x5a968154, 0xffd7132a,
+  0xb3764986, 0x1637dbf8, 0xfc191b8b, 0x595889f5,
+  0x2da8ed9c, 0x88e97fe2, 0x62c7bf91, 0xc7862def,
+  0xfb850ac9, 0x5ec498b7, 0xb4ea58c4, 0x11abcaba,
+  0x655baed3, 0xc01a3cad, 0x2a34fcde, 0x8f756ea0,
+  0xc3d4340c, 0x6695a672, 0x8cbb6601, 0x29faf47f,
+  0x5d0a9016, 0xf84b0268, 0x1265c21b, 0xb7245065,
+  0x6a638c57, 0xcf221e29, 0x250cde5a, 0x804d4c24,
+  0xf4bd284d, 0x51fcba33, 0xbbd27a40, 0x1e93e83e,
+  0x5232b292, 0xf77320ec, 0x1d5de09f, 0xb81c72e1,
+  0xccec1688, 0x69ad84f6, 0x83834485, 0x26c2d6fb,
+  0x1ac1f1dd, 0xbf8063a3, 0x55aea3d0, 0xf0ef31ae,
+  0x841f55c7, 0x215ec7b9, 0xcb7007ca, 0x6e3195b4,
+  0x2290cf18, 0x87d15d66, 0x6dff9d15, 0xc8be0f6b,
+  0xbc4e6b02, 0x190ff97c, 0xf321390f, 0x5660ab71,
+  0x4c42f79a, 0xe90365e4, 0x032da597, 0xa66c37e9,
+  0xd29c5380, 0x77ddc1fe, 0x9df3018d, 0x38b293f3,
+  0x7413c95f, 0xd1525b21, 0x3b7c9b52, 0x9e3d092c,
+  0xeacd6d45, 0x4f8cff3b, 0xa5a23f48, 0x00e3ad36,
+  0x3ce08a10, 0x99a1186e, 0x738fd81d, 0xd6ce4a63,
+  0xa23e2e0a, 0x077fbc74, 0xed517c07, 0x4810ee79,
+  0x04b1b4d5, 0xa1f026ab, 0x4bdee6d8, 0xee9f74a6,
+  0x9a6f10cf, 0x3f2e82b1, 0xd50042c2, 0x7041d0bc,
+  0xad060c8e, 0x08479ef0, 0xe2695e83, 0x4728ccfd,
+  0x33d8a894, 0x96993aea, 0x7cb7fa99, 0xd9f668e7,
+  0x9557324b, 0x3016a035, 0xda386046, 0x7f79f238,
+  0x0b899651, 0xaec8042f, 0x44e6c45c, 0xe1a75622,
+  0xdda47104, 0x78e5e37a, 0x92cb2309, 0x378ab177,
+  0x437ad51e, 0xe63b4760, 0x0c158713, 0xa954156d,
+  0xe5f54fc1, 0x40b4ddbf, 0xaa9a1dcc, 0x0fdb8fb2,
+  0x7b2bebdb, 0xde6a79a5, 0x3444b9d6, 0x91052ba8
+};
+static const uint32_t table3_[256] = {
+  0x00000000, 0xdd45aab8, 0xbf672381, 0x62228939,
+  0x7b2231f3, 0xa6679b4b, 0xc4451272, 0x1900b8ca,
+  0xf64463e6, 0x2b01c95e, 0x49234067, 0x9466eadf,
+  0x8d665215, 0x5023f8ad, 0x32017194, 0xef44db2c,
+  0xe964b13d, 0x34211b85, 0x560392bc, 0x8b463804,
+  0x924680ce, 0x4f032a76, 0x2d21a34f, 0xf06409f7,
+  0x1f20d2db, 0xc2657863, 0xa047f15a, 0x7d025be2,
+  0x6402e328, 0xb9474990, 0xdb65c0a9, 0x06206a11,
+  0xd725148b, 0x0a60be33, 0x6842370a, 0xb5079db2,
+  0xac072578, 0x71428fc0, 0x136006f9, 0xce25ac41,
+  0x2161776d, 0xfc24ddd5, 0x9e0654ec, 0x4343fe54,
+  0x5a43469e, 0x8706ec26, 0xe524651f, 0x3861cfa7,
+  0x3e41a5b6, 0xe3040f0e, 0x81268637, 0x5c632c8f,
+  0x45639445, 0x98263efd, 0xfa04b7c4, 0x27411d7c,
+  0xc805c650, 0x15406ce8, 0x7762e5d1, 0xaa274f69,
+  0xb327f7a3, 0x6e625d1b, 0x0c40d422, 0xd1057e9a,
+  0xaba65fe7, 0x76e3f55f, 0x14c17c66, 0xc984d6de,
+  0xd0846e14, 0x0dc1c4ac, 0x6fe34d95, 0xb2a6e72d,
+  0x5de23c01, 0x80a796b9, 0xe2851f80, 0x3fc0b538,
+  0x26c00df2, 0xfb85a74a, 0x99a72e73, 0x44e284cb,
+  0x42c2eeda, 0x9f874462, 0xfda5cd5b, 0x20e067e3,
+  0x39e0df29, 0xe4a57591, 0x8687fca8, 0x5bc25610,
+  0xb4868d3c, 0x69c32784, 0x0be1aebd, 0xd6a40405,
+  0xcfa4bccf, 0x12e11677, 0x70c39f4e, 0xad8635f6,
+  0x7c834b6c, 0xa1c6e1d4, 0xc3e468ed, 0x1ea1c255,
+  0x07a17a9f, 0xdae4d027, 0xb8c6591e, 0x6583f3a6,
+  0x8ac7288a, 0x57828232, 0x35a00b0b, 0xe8e5a1b3,
+  0xf1e51979, 0x2ca0b3c1, 0x4e823af8, 0x93c79040,
+  0x95e7fa51, 0x48a250e9, 0x2a80d9d0, 0xf7c57368,
+  0xeec5cba2, 0x3380611a, 0x51a2e823, 0x8ce7429b,
+  0x63a399b7, 0xbee6330f, 0xdcc4ba36, 0x0181108e,
+  0x1881a844, 0xc5c402fc, 0xa7e68bc5, 0x7aa3217d,
+  0x52a0c93f, 0x8fe56387, 0xedc7eabe, 0x30824006,
+  0x2982f8cc, 0xf4c75274, 0x96e5db4d, 0x4ba071f5,
+  0xa4e4aad9, 0x79a10061, 0x1b838958, 0xc6c623e0,
+  0xdfc69b2a, 0x02833192, 0x60a1b8ab, 0xbde41213,
+  0xbbc47802, 0x6681d2ba, 0x04a35b83, 0xd9e6f13b,
+  0xc0e649f1, 0x1da3e349, 0x7f816a70, 0xa2c4c0c8,
+  0x4d801be4, 0x90c5b15c, 0xf2e73865, 0x2fa292dd,
+  0x36a22a17, 0xebe780af, 0x89c50996, 0x5480a32e,
+  0x8585ddb4, 0x58c0770c, 0x3ae2fe35, 0xe7a7548d,
+  0xfea7ec47, 0x23e246ff, 0x41c0cfc6, 0x9c85657e,
+  0x73c1be52, 0xae8414ea, 0xcca69dd3, 0x11e3376b,
+  0x08e38fa1, 0xd5a62519, 0xb784ac20, 0x6ac10698,
+  0x6ce16c89, 0xb1a4c631, 0xd3864f08, 0x0ec3e5b0,
+  0x17c35d7a, 0xca86f7c2, 0xa8a47efb, 0x75e1d443,
+  0x9aa50f6f, 0x47e0a5d7, 0x25c22cee, 0xf8878656,
+  0xe1873e9c, 0x3cc29424, 0x5ee01d1d, 0x83a5b7a5,
+  0xf90696d8, 0x24433c60, 0x4661b559, 0x9b241fe1,
+  0x8224a72b, 0x5f610d93, 0x3d4384aa, 0xe0062e12,
+  0x0f42f53e, 0xd2075f86, 0xb025d6bf, 0x6d607c07,
+  0x7460c4cd, 0xa9256e75, 0xcb07e74c, 0x16424df4,
+  0x106227e5, 0xcd278d5d, 0xaf050464, 0x7240aedc,
+  0x6b401616, 0xb605bcae, 0xd4273597, 0x09629f2f,
+  0xe6264403, 0x3b63eebb, 0x59416782, 0x8404cd3a,
+  0x9d0475f0, 0x4041df48, 0x22635671, 0xff26fcc9,
+  0x2e238253, 0xf36628eb, 0x9144a1d2, 0x4c010b6a,
+  0x5501b3a0, 0x88441918, 0xea669021, 0x37233a99,
+  0xd867e1b5, 0x05224b0d, 0x6700c234, 0xba45688c,
+  0xa345d046, 0x7e007afe, 0x1c22f3c7, 0xc167597f,
+  0xc747336e, 0x1a0299d6, 0x782010ef, 0xa565ba57,
+  0xbc65029d, 0x6120a825, 0x0302211c, 0xde478ba4,
+  0x31035088, 0xec46fa30, 0x8e647309, 0x5321d9b1,
+  0x4a21617b, 0x9764cbc3, 0xf54642fa, 0x2803e842
+};
+
+// Used to fetch a naturally-aligned 32-bit word in little endian byte-order
+static inline uint32_t LE_LOAD32(const uint8_t *p) {
+  return DecodeFixed32(reinterpret_cast<const char*>(p));
+}
+
+uint32_t Extend(uint32_t crc, const char* buf, size_t size) {
+  const uint8_t *p = reinterpret_cast<const uint8_t *>(buf);
+  const uint8_t *e = p + size;
+  uint32_t l = crc ^ 0xffffffffu;
+
+#define STEP1 do {                              \
+    int c = (l & 0xff) ^ *p++;                  \
+    l = table0_[c] ^ (l >> 8);                  \
+} while (0)
+#define STEP4 do {                              \
+    uint32_t c = l ^ LE_LOAD32(p);              \
+    p += 4;                                     \
+    l = table3_[c & 0xff] ^                     \
+        table2_[(c >> 8) & 0xff] ^              \
+        table1_[(c >> 16) & 0xff] ^             \
+        table0_[c >> 24];                       \
+} while (0)
+
+  // Point x at first 4-byte aligned byte in string.  This might be
+  // just past the end of the string.
+  const uintptr_t pval = reinterpret_cast<uintptr_t>(p);
+  const uint8_t* x = reinterpret_cast<const uint8_t*>(((pval + 3) >> 2) << 2);
+  if (x <= e) {
+    // Process bytes until finished or p is 4-byte aligned
+    while (p != x) {
+      STEP1;
+    }
+  }
+  // Process bytes 16 at a time
+  while ((e-p) >= 16) {
+    STEP4; STEP4; STEP4; STEP4;
+  }
+  // Process bytes 4 at a time
+  while ((e-p) >= 4) {
+    STEP4;
+  }
+  // Process the last few bytes
+  while (p != e) {
+    STEP1;
+  }
+#undef STEP4
+#undef STEP1
+  return l ^ 0xffffffffu;
+}
+
+}  // namespace crc32c
+}  // namespace leveldb
diff --git a/src/leveldb/util/crc32c.h b/src/leveldb/util/crc32c.h
new file mode 100644
index 0000000000..1d7e5c075d
--- /dev/null
+++ b/src/leveldb/util/crc32c.h
@@ -0,0 +1,45 @@
+// 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.
+
+#ifndef STORAGE_LEVELDB_UTIL_CRC32C_H_
+#define STORAGE_LEVELDB_UTIL_CRC32C_H_
+
+#include <stddef.h>
+#include <stdint.h>
+
+namespace leveldb {
+namespace crc32c {
+
+// Return the crc32c of concat(A, data[0,n-1]) where init_crc is the
+// crc32c of some string A.  Extend() is often used to maintain the
+// crc32c of a stream of data.
+extern uint32_t Extend(uint32_t init_crc, const char* data, size_t n);
+
+// Return the crc32c of data[0,n-1]
+inline uint32_t Value(const char* data, size_t n) {
+  return Extend(0, data, n);
+}
+
+static const uint32_t kMaskDelta = 0xa282ead8ul;
+
+// Return a masked representation of crc.
+//
+// Motivation: it is problematic to compute the CRC of a string that
+// contains embedded CRCs.  Therefore we recommend that CRCs stored
+// somewhere (e.g., in files) should be masked before being stored.
+inline uint32_t Mask(uint32_t crc) {
+  // Rotate right by 15 bits and add a constant.
+  return ((crc >> 15) | (crc << 17)) + kMaskDelta;
+}
+
+// Return the crc whose masked representation is masked_crc.
+inline uint32_t Unmask(uint32_t masked_crc) {
+  uint32_t rot = masked_crc - kMaskDelta;
+  return ((rot >> 17) | (rot << 15));
+}
+
+}  // namespace crc32c
+}  // namespace leveldb
+
+#endif  // STORAGE_LEVELDB_UTIL_CRC32C_H_
diff --git a/src/leveldb/util/crc32c_test.cc b/src/leveldb/util/crc32c_test.cc
new file mode 100644
index 0000000000..4b957ee120
--- /dev/null
+++ b/src/leveldb/util/crc32c_test.cc
@@ -0,0 +1,72 @@
+// 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.
+
+#include "util/crc32c.h"
+#include "util/testharness.h"
+
+namespace leveldb {
+namespace crc32c {
+
+class CRC { };
+
+TEST(CRC, StandardResults) {
+  // From rfc3720 section B.4.
+  char buf[32];
+
+  memset(buf, 0, sizeof(buf));
+  ASSERT_EQ(0x8a9136aa, Value(buf, sizeof(buf)));
+
+  memset(buf, 0xff, sizeof(buf));
+  ASSERT_EQ(0x62a8ab43, Value(buf, sizeof(buf)));
+
+  for (int i = 0; i < 32; i++) {
+    buf[i] = i;
+  }
+  ASSERT_EQ(0x46dd794e, Value(buf, sizeof(buf)));
+
+  for (int i = 0; i < 32; i++) {
+    buf[i] = 31 - i;
+  }
+  ASSERT_EQ(0x113fdb5c, Value(buf, sizeof(buf)));
+
+  unsigned char data[48] = {
+    0x01, 0xc0, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00,
+    0x14, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x04, 0x00,
+    0x00, 0x00, 0x00, 0x14,
+    0x00, 0x00, 0x00, 0x18,
+    0x28, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00,
+    0x02, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00,
+  };
+  ASSERT_EQ(0xd9963a56, Value(reinterpret_cast<char*>(data), sizeof(data)));
+}
+
+TEST(CRC, Values) {
+  ASSERT_NE(Value("a", 1), Value("foo", 3));
+}
+
+TEST(CRC, Extend) {
+  ASSERT_EQ(Value("hello world", 11),
+            Extend(Value("hello ", 6), "world", 5));
+}
+
+TEST(CRC, Mask) {
+  uint32_t crc = Value("foo", 3);
+  ASSERT_NE(crc, Mask(crc));
+  ASSERT_NE(crc, Mask(Mask(crc)));
+  ASSERT_EQ(crc, Unmask(Mask(crc)));
+  ASSERT_EQ(crc, Unmask(Unmask(Mask(Mask(crc)))));
+}
+
+}  // namespace crc32c
+}  // namespace leveldb
+
+int main(int argc, char** argv) {
+  return leveldb::test::RunAllTests();
+}
diff --git a/src/leveldb/util/env.cc b/src/leveldb/util/env.cc
new file mode 100644
index 0000000000..c2600e964a
--- /dev/null
+++ b/src/leveldb/util/env.cc
@@ -0,0 +1,96 @@
+// 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.
+
+#include "leveldb/env.h"
+
+namespace leveldb {
+
+Env::~Env() {
+}
+
+SequentialFile::~SequentialFile() {
+}
+
+RandomAccessFile::~RandomAccessFile() {
+}
+
+WritableFile::~WritableFile() {
+}
+
+Logger::~Logger() {
+}
+
+FileLock::~FileLock() {
+}
+
+void Log(Logger* info_log, const char* format, ...) {
+  if (info_log != NULL) {
+    va_list ap;
+    va_start(ap, format);
+    info_log->Logv(format, ap);
+    va_end(ap);
+  }
+}
+
+static Status DoWriteStringToFile(Env* env, const Slice& data,
+                                  const std::string& fname,
+                                  bool should_sync) {
+  WritableFile* file;
+  Status s = env->NewWritableFile(fname, &file);
+  if (!s.ok()) {
+    return s;
+  }
+  s = file->Append(data);
+  if (s.ok() && should_sync) {
+    s = file->Sync();
+  }
+  if (s.ok()) {
+    s = file->Close();
+  }
+  delete file;  // Will auto-close if we did not close above
+  if (!s.ok()) {
+    env->DeleteFile(fname);
+  }
+  return s;
+}
+
+Status WriteStringToFile(Env* env, const Slice& data,
+                         const std::string& fname) {
+  return DoWriteStringToFile(env, data, fname, false);
+}
+
+Status WriteStringToFileSync(Env* env, const Slice& data,
+                             const std::string& fname) {
+  return DoWriteStringToFile(env, data, fname, true);
+}
+
+Status ReadFileToString(Env* env, const std::string& fname, std::string* data) {
+  data->clear();
+  SequentialFile* file;
+  Status s = env->NewSequentialFile(fname, &file);
+  if (!s.ok()) {
+    return s;
+  }
+  static const int kBufferSize = 8192;
+  char* space = new char[kBufferSize];
+  while (true) {
+    Slice fragment;
+    s = file->Read(kBufferSize, &fragment, space);
+    if (!s.ok()) {
+      break;
+    }
+    data->append(fragment.data(), fragment.size());
+    if (fragment.empty()) {
+      break;
+    }
+  }
+  delete[] space;
+  delete file;
+  return s;
+}
+
+EnvWrapper::~EnvWrapper() {
+}
+
+}  // namespace leveldb
diff --git a/src/leveldb/util/env_posix.cc b/src/leveldb/util/env_posix.cc
new file mode 100644
index 0000000000..cb1f6fc05a
--- /dev/null
+++ b/src/leveldb/util/env_posix.cc
@@ -0,0 +1,609 @@
+// 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.
+
+#include <deque>
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <time.h>
+#include <unistd.h>
+#if defined(LEVELDB_PLATFORM_ANDROID)
+#include <sys/stat.h>
+#endif
+#include "leveldb/env.h"
+#include "leveldb/slice.h"
+#include "port/port.h"
+#include "util/logging.h"
+#include "util/posix_logger.h"
+
+namespace leveldb {
+
+namespace {
+
+static Status IOError(const std::string& context, int err_number) {
+  return Status::IOError(context, strerror(err_number));
+}
+
+class PosixSequentialFile: public SequentialFile {
+ private:
+  std::string filename_;
+  FILE* file_;
+
+ public:
+  PosixSequentialFile(const std::string& fname, FILE* f)
+      : filename_(fname), file_(f) { }
+  virtual ~PosixSequentialFile() { fclose(file_); }
+
+  virtual Status Read(size_t n, Slice* result, char* scratch) {
+    Status s;
+    size_t r = fread_unlocked(scratch, 1, n, file_);
+    *result = Slice(scratch, r);
+    if (r < n) {
+      if (feof(file_)) {
+        // We leave status as ok if we hit the end of the file
+      } else {
+        // A partial read with an error: return a non-ok status
+        s = IOError(filename_, errno);
+      }
+    }
+    return s;
+  }
+
+  virtual Status Skip(uint64_t n) {
+    if (fseek(file_, n, SEEK_CUR)) {
+      return IOError(filename_, errno);
+    }
+    return Status::OK();
+  }
+};
+
+// pread() based random-access
+class PosixRandomAccessFile: public RandomAccessFile {
+ private:
+  std::string filename_;
+  int fd_;
+
+ public:
+  PosixRandomAccessFile(const std::string& fname, int fd)
+      : filename_(fname), fd_(fd) { }
+  virtual ~PosixRandomAccessFile() { close(fd_); }
+
+  virtual Status Read(uint64_t offset, size_t n, Slice* result,
+                      char* scratch) const {
+    Status s;
+    ssize_t r = pread(fd_, scratch, n, static_cast<off_t>(offset));
+    *result = Slice(scratch, (r < 0) ? 0 : r);
+    if (r < 0) {
+      // An error: return a non-ok status
+      s = IOError(filename_, errno);
+    }
+    return s;
+  }
+};
+
+// mmap() based random-access
+class PosixMmapReadableFile: public RandomAccessFile {
+ private:
+  std::string filename_;
+  void* mmapped_region_;
+  size_t length_;
+
+ public:
+  // base[0,length-1] contains the mmapped contents of the file.
+  PosixMmapReadableFile(const std::string& fname, void* base, size_t length)
+      : filename_(fname), mmapped_region_(base), length_(length) { }
+  virtual ~PosixMmapReadableFile() { munmap(mmapped_region_, length_); }
+
+  virtual Status Read(uint64_t offset, size_t n, Slice* result,
+                      char* scratch) const {
+    Status s;
+    if (offset + n > length_) {
+      *result = Slice();
+      s = IOError(filename_, EINVAL);
+    } else {
+      *result = Slice(reinterpret_cast<char*>(mmapped_region_) + offset, n);
+    }
+    return s;
+  }
+};
+
+// We preallocate up to an extra megabyte and use memcpy to append new
+// data to the file.  This is safe since we either properly close the
+// file before reading from it, or for log files, the reading code
+// knows enough to skip zero suffixes.
+class PosixMmapFile : public WritableFile {
+ private:
+  std::string filename_;
+  int fd_;
+  size_t page_size_;
+  size_t map_size_;       // How much extra memory to map at a time
+  char* base_;            // The mapped region
+  char* limit_;           // Limit of the mapped region
+  char* dst_;             // Where to write next  (in range [base_,limit_])
+  char* last_sync_;       // Where have we synced up to
+  uint64_t file_offset_;  // Offset of base_ in file
+
+  // Have we done an munmap of unsynced data?
+  bool pending_sync_;
+
+  // Roundup x to a multiple of y
+  static size_t Roundup(size_t x, size_t y) {
+    return ((x + y - 1) / y) * y;
+  }
+
+  size_t TruncateToPageBoundary(size_t s) {
+    s -= (s & (page_size_ - 1));
+    assert((s % page_size_) == 0);
+    return s;
+  }
+
+  bool UnmapCurrentRegion() {
+    bool result = true;
+    if (base_ != NULL) {
+      if (last_sync_ < limit_) {
+        // Defer syncing this data until next Sync() call, if any
+        pending_sync_ = true;
+      }
+      if (munmap(base_, limit_ - base_) != 0) {
+        result = false;
+      }
+      file_offset_ += limit_ - base_;
+      base_ = NULL;
+      limit_ = NULL;
+      last_sync_ = NULL;
+      dst_ = NULL;
+
+      // Increase the amount we map the next time, but capped at 1MB
+      if (map_size_ < (1<<20)) {
+        map_size_ *= 2;
+      }
+    }
+    return result;
+  }
+
+  bool MapNewRegion() {
+    assert(base_ == NULL);
+    if (ftruncate(fd_, file_offset_ + map_size_) < 0) {
+      return false;
+    }
+    void* ptr = mmap(NULL, map_size_, PROT_READ | PROT_WRITE, MAP_SHARED,
+                     fd_, file_offset_);
+    if (ptr == MAP_FAILED) {
+      return false;
+    }
+    base_ = reinterpret_cast<char*>(ptr);
+    limit_ = base_ + map_size_;
+    dst_ = base_;
+    last_sync_ = base_;
+    return true;
+  }
+
+ public:
+  PosixMmapFile(const std::string& fname, int fd, size_t page_size)
+      : filename_(fname),
+        fd_(fd),
+        page_size_(page_size),
+        map_size_(Roundup(65536, page_size)),
+        base_(NULL),
+        limit_(NULL),
+        dst_(NULL),
+        last_sync_(NULL),
+        file_offset_(0),
+        pending_sync_(false) {
+    assert((page_size & (page_size - 1)) == 0);
+  }
+
+
+  ~PosixMmapFile() {
+    if (fd_ >= 0) {
+      PosixMmapFile::Close();
+    }
+  }
+
+  virtual Status Append(const Slice& data) {
+    const char* src = data.data();
+    size_t left = data.size();
+    while (left > 0) {
+      assert(base_ <= dst_);
+      assert(dst_ <= limit_);
+      size_t avail = limit_ - dst_;
+      if (avail == 0) {
+        if (!UnmapCurrentRegion() ||
+            !MapNewRegion()) {
+          return IOError(filename_, errno);
+        }
+      }
+
+      size_t n = (left <= avail) ? left : avail;
+      memcpy(dst_, src, n);
+      dst_ += n;
+      src += n;
+      left -= n;
+    }
+    return Status::OK();
+  }
+
+  virtual Status Close() {
+    Status s;
+    size_t unused = limit_ - dst_;
+    if (!UnmapCurrentRegion()) {
+      s = IOError(filename_, errno);
+    } else if (unused > 0) {
+      // Trim the extra space at the end of the file
+      if (ftruncate(fd_, file_offset_ - unused) < 0) {
+        s = IOError(filename_, errno);
+      }
+    }
+
+    if (close(fd_) < 0) {
+      if (s.ok()) {
+        s = IOError(filename_, errno);
+      }
+    }
+
+    fd_ = -1;
+    base_ = NULL;
+    limit_ = NULL;
+    return s;
+  }
+
+  virtual Status Flush() {
+    return Status::OK();
+  }
+
+  virtual Status Sync() {
+    Status s;
+
+    if (pending_sync_) {
+      // Some unmapped data was not synced
+      pending_sync_ = false;
+      if (fdatasync(fd_) < 0) {
+        s = IOError(filename_, errno);
+      }
+    }
+
+    if (dst_ > last_sync_) {
+      // Find the beginnings of the pages that contain the first and last
+      // bytes to be synced.
+      size_t p1 = TruncateToPageBoundary(last_sync_ - base_);
+      size_t p2 = TruncateToPageBoundary(dst_ - base_ - 1);
+      last_sync_ = dst_;
+      if (msync(base_ + p1, p2 - p1 + page_size_, MS_SYNC) < 0) {
+        s = IOError(filename_, errno);
+      }
+    }
+
+    return s;
+  }
+};
+
+static int LockOrUnlock(int fd, bool lock) {
+  errno = 0;
+  struct flock f;
+  memset(&f, 0, sizeof(f));
+  f.l_type = (lock ? F_WRLCK : F_UNLCK);
+  f.l_whence = SEEK_SET;
+  f.l_start = 0;
+  f.l_len = 0;        // Lock/unlock entire file
+  return fcntl(fd, F_SETLK, &f);
+}
+
+class PosixFileLock : public FileLock {
+ public:
+  int fd_;
+};
+
+class PosixEnv : public Env {
+ public:
+  PosixEnv();
+  virtual ~PosixEnv() {
+    fprintf(stderr, "Destroying Env::Default()\n");
+    exit(1);
+  }
+
+  virtual Status NewSequentialFile(const std::string& fname,
+                                   SequentialFile** result) {
+    FILE* f = fopen(fname.c_str(), "r");
+    if (f == NULL) {
+      *result = NULL;
+      return IOError(fname, errno);
+    } else {
+      *result = new PosixSequentialFile(fname, f);
+      return Status::OK();
+    }
+  }
+
+  virtual Status NewRandomAccessFile(const std::string& fname,
+                                     RandomAccessFile** result) {
+    *result = NULL;
+    Status s;
+    int fd = open(fname.c_str(), O_RDONLY);
+    if (fd < 0) {
+      s = IOError(fname, errno);
+    } else if (sizeof(void*) >= 8) {
+      // Use mmap when virtual address-space is plentiful.
+      uint64_t size;
+      s = GetFileSize(fname, &size);
+      if (s.ok()) {
+        void* base = mmap(NULL, size, PROT_READ, MAP_SHARED, fd, 0);
+        if (base != MAP_FAILED) {
+          *result = new PosixMmapReadableFile(fname, base, size);
+        } else {
+          s = IOError(fname, errno);
+        }
+      }
+      close(fd);
+    } else {
+      *result = new PosixRandomAccessFile(fname, fd);
+    }
+    return s;
+  }
+
+  virtual Status NewWritableFile(const std::string& fname,
+                                 WritableFile** result) {
+    Status s;
+    const int fd = open(fname.c_str(), O_CREAT | O_RDWR | O_TRUNC, 0644);
+    if (fd < 0) {
+      *result = NULL;
+      s = IOError(fname, errno);
+    } else {
+      *result = new PosixMmapFile(fname, fd, page_size_);
+    }
+    return s;
+  }
+
+  virtual bool FileExists(const std::string& fname) {
+    return access(fname.c_str(), F_OK) == 0;
+  }
+
+  virtual Status GetChildren(const std::string& dir,
+                             std::vector<std::string>* result) {
+    result->clear();
+    DIR* d = opendir(dir.c_str());
+    if (d == NULL) {
+      return IOError(dir, errno);
+    }
+    struct dirent* entry;
+    while ((entry = readdir(d)) != NULL) {
+      result->push_back(entry->d_name);
+    }
+    closedir(d);
+    return Status::OK();
+  }
+
+  virtual Status DeleteFile(const std::string& fname) {
+    Status result;
+    if (unlink(fname.c_str()) != 0) {
+      result = IOError(fname, errno);
+    }
+    return result;
+  };
+
+  virtual Status CreateDir(const std::string& name) {
+    Status result;
+    if (mkdir(name.c_str(), 0755) != 0) {
+      result = IOError(name, errno);
+    }
+    return result;
+  };
+
+  virtual Status DeleteDir(const std::string& name) {
+    Status result;
+    if (rmdir(name.c_str()) != 0) {
+      result = IOError(name, errno);
+    }
+    return result;
+  };
+
+  virtual Status GetFileSize(const std::string& fname, uint64_t* size) {
+    Status s;
+    struct stat sbuf;
+    if (stat(fname.c_str(), &sbuf) != 0) {
+      *size = 0;
+      s = IOError(fname, errno);
+    } else {
+      *size = sbuf.st_size;
+    }
+    return s;
+  }
+
+  virtual Status RenameFile(const std::string& src, const std::string& target) {
+    Status result;
+    if (rename(src.c_str(), target.c_str()) != 0) {
+      result = IOError(src, errno);
+    }
+    return result;
+  }
+
+  virtual Status LockFile(const std::string& fname, FileLock** lock) {
+    *lock = NULL;
+    Status result;
+    int fd = open(fname.c_str(), O_RDWR | O_CREAT, 0644);
+    if (fd < 0) {
+      result = IOError(fname, errno);
+    } else if (LockOrUnlock(fd, true) == -1) {
+      result = IOError("lock " + fname, errno);
+      close(fd);
+    } else {
+      PosixFileLock* my_lock = new PosixFileLock;
+      my_lock->fd_ = fd;
+      *lock = my_lock;
+    }
+    return result;
+  }
+
+  virtual Status UnlockFile(FileLock* lock) {
+    PosixFileLock* my_lock = reinterpret_cast<PosixFileLock*>(lock);
+    Status result;
+    if (LockOrUnlock(my_lock->fd_, false) == -1) {
+      result = IOError("unlock", errno);
+    }
+    close(my_lock->fd_);
+    delete my_lock;
+    return result;
+  }
+
+  virtual void Schedule(void (*function)(void*), void* arg);
+
+  virtual void StartThread(void (*function)(void* arg), void* arg);
+
+  virtual Status GetTestDirectory(std::string* result) {
+    const char* env = getenv("TEST_TMPDIR");
+    if (env && env[0] != '\0') {
+      *result = env;
+    } else {
+      char buf[100];
+      snprintf(buf, sizeof(buf), "/tmp/leveldbtest-%d", int(geteuid()));
+      *result = buf;
+    }
+    // Directory may already exist
+    CreateDir(*result);
+    return Status::OK();
+  }
+
+  static uint64_t gettid() {
+    pthread_t tid = pthread_self();
+    uint64_t thread_id = 0;
+    memcpy(&thread_id, &tid, std::min(sizeof(thread_id), sizeof(tid)));
+    return thread_id;
+  }
+
+  virtual Status NewLogger(const std::string& fname, Logger** result) {
+    FILE* f = fopen(fname.c_str(), "w");
+    if (f == NULL) {
+      *result = NULL;
+      return IOError(fname, errno);
+    } else {
+      *result = new PosixLogger(f, &PosixEnv::gettid);
+      return Status::OK();
+    }
+  }
+
+  virtual uint64_t NowMicros() {
+    struct timeval tv;
+    gettimeofday(&tv, NULL);
+    return static_cast<uint64_t>(tv.tv_sec) * 1000000 + tv.tv_usec;
+  }
+
+  virtual void SleepForMicroseconds(int micros) {
+    usleep(micros);
+  }
+
+ private:
+  void PthreadCall(const char* label, int result) {
+    if (result != 0) {
+      fprintf(stderr, "pthread %s: %s\n", label, strerror(result));
+      exit(1);
+    }
+  }
+
+  // BGThread() is the body of the background thread
+  void BGThread();
+  static void* BGThreadWrapper(void* arg) {
+    reinterpret_cast<PosixEnv*>(arg)->BGThread();
+    return NULL;
+  }
+
+  size_t page_size_;
+  pthread_mutex_t mu_;
+  pthread_cond_t bgsignal_;
+  pthread_t bgthread_;
+  bool started_bgthread_;
+
+  // Entry per Schedule() call
+  struct BGItem { void* arg; void (*function)(void*); };
+  typedef std::deque<BGItem> BGQueue;
+  BGQueue queue_;
+};
+
+PosixEnv::PosixEnv() : page_size_(getpagesize()),
+                       started_bgthread_(false) {
+  PthreadCall("mutex_init", pthread_mutex_init(&mu_, NULL));
+  PthreadCall("cvar_init", pthread_cond_init(&bgsignal_, NULL));
+}
+
+void PosixEnv::Schedule(void (*function)(void*), void* arg) {
+  PthreadCall("lock", pthread_mutex_lock(&mu_));
+
+  // Start background thread if necessary
+  if (!started_bgthread_) {
+    started_bgthread_ = true;
+    PthreadCall(
+        "create thread",
+        pthread_create(&bgthread_, NULL,  &PosixEnv::BGThreadWrapper, this));
+  }
+
+  // If the queue is currently empty, the background thread may currently be
+  // waiting.
+  if (queue_.empty()) {
+    PthreadCall("signal", pthread_cond_signal(&bgsignal_));
+  }
+
+  // Add to priority queue
+  queue_.push_back(BGItem());
+  queue_.back().function = function;
+  queue_.back().arg = arg;
+
+  PthreadCall("unlock", pthread_mutex_unlock(&mu_));
+}
+
+void PosixEnv::BGThread() {
+  while (true) {
+    // Wait until there is an item that is ready to run
+    PthreadCall("lock", pthread_mutex_lock(&mu_));
+    while (queue_.empty()) {
+      PthreadCall("wait", pthread_cond_wait(&bgsignal_, &mu_));
+    }
+
+    void (*function)(void*) = queue_.front().function;
+    void* arg = queue_.front().arg;
+    queue_.pop_front();
+
+    PthreadCall("unlock", pthread_mutex_unlock(&mu_));
+    (*function)(arg);
+  }
+}
+
+namespace {
+struct StartThreadState {
+  void (*user_function)(void*);
+  void* arg;
+};
+}
+static void* StartThreadWrapper(void* arg) {
+  StartThreadState* state = reinterpret_cast<StartThreadState*>(arg);
+  state->user_function(state->arg);
+  delete state;
+  return NULL;
+}
+
+void PosixEnv::StartThread(void (*function)(void* arg), void* arg) {
+  pthread_t t;
+  StartThreadState* state = new StartThreadState;
+  state->user_function = function;
+  state->arg = arg;
+  PthreadCall("start thread",
+              pthread_create(&t, NULL,  &StartThreadWrapper, state));
+}
+
+}  // namespace
+
+static pthread_once_t once = PTHREAD_ONCE_INIT;
+static Env* default_env;
+static void InitDefaultEnv() { default_env = new PosixEnv; }
+
+Env* Env::Default() {
+  pthread_once(&once, InitDefaultEnv);
+  return default_env;
+}
+
+}  // namespace leveldb
diff --git a/src/leveldb/util/env_test.cc b/src/leveldb/util/env_test.cc
new file mode 100644
index 0000000000..b72cb44384
--- /dev/null
+++ b/src/leveldb/util/env_test.cc
@@ -0,0 +1,104 @@
+// 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.
+
+#include "leveldb/env.h"
+
+#include "port/port.h"
+#include "util/testharness.h"
+
+namespace leveldb {
+
+static const int kDelayMicros = 100000;
+
+class EnvPosixTest {
+ private:
+  port::Mutex mu_;
+  std::string events_;
+
+ public:
+  Env* env_;
+  EnvPosixTest() : env_(Env::Default()) { }
+};
+
+static void SetBool(void* ptr) {
+  reinterpret_cast<port::AtomicPointer*>(ptr)->NoBarrier_Store(ptr);
+}
+
+TEST(EnvPosixTest, RunImmediately) {
+  port::AtomicPointer called (NULL);
+  env_->Schedule(&SetBool, &called);
+  Env::Default()->SleepForMicroseconds(kDelayMicros);
+  ASSERT_TRUE(called.NoBarrier_Load() != NULL);
+}
+
+TEST(EnvPosixTest, RunMany) {
+  port::AtomicPointer last_id (NULL);
+
+  struct CB {
+    port::AtomicPointer* last_id_ptr;   // Pointer to shared slot
+    uintptr_t id;             // Order# for the execution of this callback
+
+    CB(port::AtomicPointer* p, int i) : last_id_ptr(p), id(i) { }
+
+    static void Run(void* v) {
+      CB* cb = reinterpret_cast<CB*>(v);
+      void* cur = cb->last_id_ptr->NoBarrier_Load();
+      ASSERT_EQ(cb->id-1, reinterpret_cast<uintptr_t>(cur));
+      cb->last_id_ptr->Release_Store(reinterpret_cast<void*>(cb->id));
+    }
+  };
+
+  // Schedule in different order than start time
+  CB cb1(&last_id, 1);
+  CB cb2(&last_id, 2);
+  CB cb3(&last_id, 3);
+  CB cb4(&last_id, 4);
+  env_->Schedule(&CB::Run, &cb1);
+  env_->Schedule(&CB::Run, &cb2);
+  env_->Schedule(&CB::Run, &cb3);
+  env_->Schedule(&CB::Run, &cb4);
+
+  Env::Default()->SleepForMicroseconds(kDelayMicros);
+  void* cur = last_id.Acquire_Load();
+  ASSERT_EQ(4, reinterpret_cast<uintptr_t>(cur));
+}
+
+struct State {
+  port::Mutex mu;
+  int val;
+  int num_running;
+};
+
+static void ThreadBody(void* arg) {
+  State* s = reinterpret_cast<State*>(arg);
+  s->mu.Lock();
+  s->val += 1;
+  s->num_running -= 1;
+  s->mu.Unlock();
+}
+
+TEST(EnvPosixTest, StartThread) {
+  State state;
+  state.val = 0;
+  state.num_running = 3;
+  for (int i = 0; i < 3; i++) {
+    env_->StartThread(&ThreadBody, &state);
+  }
+  while (true) {
+    state.mu.Lock();
+    int num = state.num_running;
+    state.mu.Unlock();
+    if (num == 0) {
+      break;
+    }
+    Env::Default()->SleepForMicroseconds(kDelayMicros);
+  }
+  ASSERT_EQ(state.val, 3);
+}
+
+}  // namespace leveldb
+
+int main(int argc, char** argv) {
+  return leveldb::test::RunAllTests();
+}
diff --git a/src/leveldb/util/filter_policy.cc b/src/leveldb/util/filter_policy.cc
new file mode 100644
index 0000000000..7b045c8c91
--- /dev/null
+++ b/src/leveldb/util/filter_policy.cc
@@ -0,0 +1,11 @@
+// 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 "leveldb/filter_policy.h"
+
+namespace leveldb {
+
+FilterPolicy::~FilterPolicy() { }
+
+}  // namespace leveldb
diff --git a/src/leveldb/util/hash.cc b/src/leveldb/util/hash.cc
new file mode 100644
index 0000000000..ba1818082d
--- /dev/null
+++ b/src/leveldb/util/hash.cc
@@ -0,0 +1,45 @@
+// 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.
+
+#include <string.h>
+#include "util/coding.h"
+#include "util/hash.h"
+
+namespace leveldb {
+
+uint32_t Hash(const char* data, size_t n, uint32_t seed) {
+  // Similar to murmur hash
+  const uint32_t m = 0xc6a4a793;
+  const uint32_t r = 24;
+  const char* limit = data + n;
+  uint32_t h = seed ^ (n * m);
+
+  // Pick up four bytes at a time
+  while (data + 4 <= limit) {
+    uint32_t w = DecodeFixed32(data);
+    data += 4;
+    h += w;
+    h *= m;
+    h ^= (h >> 16);
+  }
+
+  // Pick up remaining bytes
+  switch (limit - data) {
+    case 3:
+      h += data[2] << 16;
+      // fall through
+    case 2:
+      h += data[1] << 8;
+      // fall through
+    case 1:
+      h += data[0];
+      h *= m;
+      h ^= (h >> r);
+      break;
+  }
+  return h;
+}
+
+
+}  // namespace leveldb
diff --git a/src/leveldb/util/hash.h b/src/leveldb/util/hash.h
new file mode 100644
index 0000000000..8889d56be8
--- /dev/null
+++ b/src/leveldb/util/hash.h
@@ -0,0 +1,19 @@
+// 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.
+//
+// Simple hash function used for internal data structures
+
+#ifndef STORAGE_LEVELDB_UTIL_HASH_H_
+#define STORAGE_LEVELDB_UTIL_HASH_H_
+
+#include <stddef.h>
+#include <stdint.h>
+
+namespace leveldb {
+
+extern uint32_t Hash(const char* data, size_t n, uint32_t seed);
+
+}
+
+#endif  // STORAGE_LEVELDB_UTIL_HASH_H_
diff --git a/src/leveldb/util/histogram.cc b/src/leveldb/util/histogram.cc
new file mode 100644
index 0000000000..bb95f583ea
--- /dev/null
+++ b/src/leveldb/util/histogram.cc
@@ -0,0 +1,139 @@
+// 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.
+
+#include <math.h>
+#include <stdio.h>
+#include "port/port.h"
+#include "util/histogram.h"
+
+namespace leveldb {
+
+const double Histogram::kBucketLimit[kNumBuckets] = {
+  1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20, 25, 30, 35, 40, 45,
+  50, 60, 70, 80, 90, 100, 120, 140, 160, 180, 200, 250, 300, 350, 400, 450,
+  500, 600, 700, 800, 900, 1000, 1200, 1400, 1600, 1800, 2000, 2500, 3000,
+  3500, 4000, 4500, 5000, 6000, 7000, 8000, 9000, 10000, 12000, 14000,
+  16000, 18000, 20000, 25000, 30000, 35000, 40000, 45000, 50000, 60000,
+  70000, 80000, 90000, 100000, 120000, 140000, 160000, 180000, 200000,
+  250000, 300000, 350000, 400000, 450000, 500000, 600000, 700000, 800000,
+  900000, 1000000, 1200000, 1400000, 1600000, 1800000, 2000000, 2500000,
+  3000000, 3500000, 4000000, 4500000, 5000000, 6000000, 7000000, 8000000,
+  9000000, 10000000, 12000000, 14000000, 16000000, 18000000, 20000000,
+  25000000, 30000000, 35000000, 40000000, 45000000, 50000000, 60000000,
+  70000000, 80000000, 90000000, 100000000, 120000000, 140000000, 160000000,
+  180000000, 200000000, 250000000, 300000000, 350000000, 400000000,
+  450000000, 500000000, 600000000, 700000000, 800000000, 900000000,
+  1000000000, 1200000000, 1400000000, 1600000000, 1800000000, 2000000000,
+  2500000000.0, 3000000000.0, 3500000000.0, 4000000000.0, 4500000000.0,
+  5000000000.0, 6000000000.0, 7000000000.0, 8000000000.0, 9000000000.0,
+  1e200,
+};
+
+void Histogram::Clear() {
+  min_ = kBucketLimit[kNumBuckets-1];
+  max_ = 0;
+  num_ = 0;
+  sum_ = 0;
+  sum_squares_ = 0;
+  for (int i = 0; i < kNumBuckets; i++) {
+    buckets_[i] = 0;
+  }
+}
+
+void Histogram::Add(double value) {
+  // Linear search is fast enough for our usage in db_bench
+  int b = 0;
+  while (b < kNumBuckets - 1 && kBucketLimit[b] <= value) {
+    b++;
+  }
+  buckets_[b] += 1.0;
+  if (min_ > value) min_ = value;
+  if (max_ < value) max_ = value;
+  num_++;
+  sum_ += value;
+  sum_squares_ += (value * value);
+}
+
+void Histogram::Merge(const Histogram& other) {
+  if (other.min_ < min_) min_ = other.min_;
+  if (other.max_ > max_) max_ = other.max_;
+  num_ += other.num_;
+  sum_ += other.sum_;
+  sum_squares_ += other.sum_squares_;
+  for (int b = 0; b < kNumBuckets; b++) {
+    buckets_[b] += other.buckets_[b];
+  }
+}
+
+double Histogram::Median() const {
+  return Percentile(50.0);
+}
+
+double Histogram::Percentile(double p) const {
+  double threshold = num_ * (p / 100.0);
+  double sum = 0;
+  for (int b = 0; b < kNumBuckets; b++) {
+    sum += buckets_[b];
+    if (sum >= threshold) {
+      // Scale linearly within this bucket
+      double left_point = (b == 0) ? 0 : kBucketLimit[b-1];
+      double right_point = kBucketLimit[b];
+      double left_sum = sum - buckets_[b];
+      double right_sum = sum;
+      double pos = (threshold - left_sum) / (right_sum - left_sum);
+      double r = left_point + (right_point - left_point) * pos;
+      if (r < min_) r = min_;
+      if (r > max_) r = max_;
+      return r;
+    }
+  }
+  return max_;
+}
+
+double Histogram::Average() const {
+  if (num_ == 0.0) return 0;
+  return sum_ / num_;
+}
+
+double Histogram::StandardDeviation() const {
+  if (num_ == 0.0) return 0;
+  double variance = (sum_squares_ * num_ - sum_ * sum_) / (num_ * num_);
+  return sqrt(variance);
+}
+
+std::string Histogram::ToString() const {
+  std::string r;
+  char buf[200];
+  snprintf(buf, sizeof(buf),
+           "Count: %.0f  Average: %.4f  StdDev: %.2f\n",
+           num_, Average(), StandardDeviation());
+  r.append(buf);
+  snprintf(buf, sizeof(buf),
+           "Min: %.4f  Median: %.4f  Max: %.4f\n",
+           (num_ == 0.0 ? 0.0 : min_), Median(), max_);
+  r.append(buf);
+  r.append("------------------------------------------------------\n");
+  const double mult = 100.0 / num_;
+  double sum = 0;
+  for (int b = 0; b < kNumBuckets; b++) {
+    if (buckets_[b] <= 0.0) continue;
+    sum += buckets_[b];
+    snprintf(buf, sizeof(buf),
+             "[ %7.0f, %7.0f ) %7.0f %7.3f%% %7.3f%% ",
+             ((b == 0) ? 0.0 : kBucketLimit[b-1]),      // left
+             kBucketLimit[b],                           // right
+             buckets_[b],                               // count
+             mult * buckets_[b],                        // percentage
+             mult * sum);                               // cumulative percentage
+    r.append(buf);
+
+    // Add hash marks based on percentage; 20 marks for 100%.
+    int marks = static_cast<int>(20*(buckets_[b] / num_) + 0.5);
+    r.append(marks, '#');
+    r.push_back('\n');
+  }
+  return r;
+}
+
+}  // namespace leveldb
diff --git a/src/leveldb/util/histogram.h b/src/leveldb/util/histogram.h
new file mode 100644
index 0000000000..1ef9f3c8ab
--- /dev/null
+++ b/src/leveldb/util/histogram.h
@@ -0,0 +1,42 @@
+// 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.
+
+#ifndef STORAGE_LEVELDB_UTIL_HISTOGRAM_H_
+#define STORAGE_LEVELDB_UTIL_HISTOGRAM_H_
+
+#include <string>
+
+namespace leveldb {
+
+class Histogram {
+ public:
+  Histogram() { }
+  ~Histogram() { }
+
+  void Clear();
+  void Add(double value);
+  void Merge(const Histogram& other);
+
+  std::string ToString() const;
+
+ private:
+  double min_;
+  double max_;
+  double num_;
+  double sum_;
+  double sum_squares_;
+
+  enum { kNumBuckets = 154 };
+  static const double kBucketLimit[kNumBuckets];
+  double buckets_[kNumBuckets];
+
+  double Median() const;
+  double Percentile(double p) const;
+  double Average() const;
+  double StandardDeviation() const;
+};
+
+}  // namespace leveldb
+
+#endif  // STORAGE_LEVELDB_UTIL_HISTOGRAM_H_
diff --git a/src/leveldb/util/logging.cc b/src/leveldb/util/logging.cc
new file mode 100644
index 0000000000..22cf278512
--- /dev/null
+++ b/src/leveldb/util/logging.cc
@@ -0,0 +1,81 @@
+// 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.
+
+#include "util/logging.h"
+
+#include <errno.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include "leveldb/env.h"
+#include "leveldb/slice.h"
+
+namespace leveldb {
+
+void AppendNumberTo(std::string* str, uint64_t num) {
+  char buf[30];
+  snprintf(buf, sizeof(buf), "%llu", (unsigned long long) num);
+  str->append(buf);
+}
+
+void AppendEscapedStringTo(std::string* str, const Slice& value) {
+  for (size_t i = 0; i < value.size(); i++) {
+    char c = value[i];
+    if (c >= ' ' && c <= '~') {
+      str->push_back(c);
+    } else {
+      char buf[10];
+      snprintf(buf, sizeof(buf), "\\x%02x",
+               static_cast<unsigned int>(c) & 0xff);
+      str->append(buf);
+    }
+  }
+}
+
+std::string NumberToString(uint64_t num) {
+  std::string r;
+  AppendNumberTo(&r, num);
+  return r;
+}
+
+std::string EscapeString(const Slice& value) {
+  std::string r;
+  AppendEscapedStringTo(&r, value);
+  return r;
+}
+
+bool ConsumeChar(Slice* in, char c) {
+  if (!in->empty() && (*in)[0] == c) {
+    in->remove_prefix(1);
+    return true;
+  } else {
+    return false;
+  }
+}
+
+bool ConsumeDecimalNumber(Slice* in, uint64_t* val) {
+  uint64_t v = 0;
+  int digits = 0;
+  while (!in->empty()) {
+    char c = (*in)[0];
+    if (c >= '0' && c <= '9') {
+      ++digits;
+      const int delta = (c - '0');
+      static const uint64_t kMaxUint64 = ~static_cast<uint64_t>(0);
+      if (v > kMaxUint64/10 ||
+          (v == kMaxUint64/10 && delta > kMaxUint64%10)) {
+        // Overflow
+        return false;
+      }
+      v = (v * 10) + delta;
+      in->remove_prefix(1);
+    } else {
+      break;
+    }
+  }
+  *val = v;
+  return (digits > 0);
+}
+
+}  // namespace leveldb
diff --git a/src/leveldb/util/logging.h b/src/leveldb/util/logging.h
new file mode 100644
index 0000000000..b0c5da813e
--- /dev/null
+++ b/src/leveldb/util/logging.h
@@ -0,0 +1,47 @@
+// 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.
+//
+// Must not be included from any .h files to avoid polluting the namespace
+// with macros.
+
+#ifndef STORAGE_LEVELDB_UTIL_LOGGING_H_
+#define STORAGE_LEVELDB_UTIL_LOGGING_H_
+
+#include <stdio.h>
+#include <stdint.h>
+#include <string>
+#include "port/port.h"
+
+namespace leveldb {
+
+class Slice;
+class WritableFile;
+
+// Append a human-readable printout of "num" to *str
+extern void AppendNumberTo(std::string* str, uint64_t num);
+
+// Append a human-readable printout of "value" to *str.
+// Escapes any non-printable characters found in "value".
+extern void AppendEscapedStringTo(std::string* str, const Slice& value);
+
+// Return a human-readable printout of "num"
+extern std::string NumberToString(uint64_t num);
+
+// Return a human-readable version of "value".
+// Escapes any non-printable characters found in "value".
+extern std::string EscapeString(const Slice& value);
+
+// If *in starts with "c", advances *in past the first character and
+// returns true.  Otherwise, returns false.
+extern bool ConsumeChar(Slice* in, char c);
+
+// Parse a human-readable number from "*in" into *value.  On success,
+// advances "*in" past the consumed number and sets "*val" to the
+// numeric value.  Otherwise, returns false and leaves *in in an
+// unspecified state.
+extern bool ConsumeDecimalNumber(Slice* in, uint64_t* val);
+
+}  // namespace leveldb
+
+#endif  // STORAGE_LEVELDB_UTIL_LOGGING_H_
diff --git a/src/leveldb/util/mutexlock.h b/src/leveldb/util/mutexlock.h
new file mode 100644
index 0000000000..c3f3306d3e
--- /dev/null
+++ b/src/leveldb/util/mutexlock.h
@@ -0,0 +1,39 @@
+// 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.
+
+#ifndef STORAGE_LEVELDB_UTIL_MUTEXLOCK_H_
+#define STORAGE_LEVELDB_UTIL_MUTEXLOCK_H_
+
+#include "port/port.h"
+
+namespace leveldb {
+
+// Helper class that locks a mutex on construction and unlocks the mutex when
+// the destructor of the MutexLock object is invoked.
+//
+// Typical usage:
+//
+//   void MyClass::MyMethod() {
+//     MutexLock l(&mu_);       // mu_ is an instance variable
+//     ... some complex code, possibly with multiple return paths ...
+//   }
+
+class MutexLock {
+ public:
+  explicit MutexLock(port::Mutex *mu) : mu_(mu) {
+    this->mu_->Lock();
+  }
+  ~MutexLock() { this->mu_->Unlock(); }
+
+ private:
+  port::Mutex *const mu_;
+  // No copying allowed
+  MutexLock(const MutexLock&);
+  void operator=(const MutexLock&);
+};
+
+}  // namespace leveldb
+
+
+#endif  // STORAGE_LEVELDB_UTIL_MUTEXLOCK_H_
diff --git a/src/leveldb/util/options.cc b/src/leveldb/util/options.cc
new file mode 100644
index 0000000000..76af5b9302
--- /dev/null
+++ b/src/leveldb/util/options.cc
@@ -0,0 +1,29 @@
+// 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.
+
+#include "leveldb/options.h"
+
+#include "leveldb/comparator.h"
+#include "leveldb/env.h"
+
+namespace leveldb {
+
+Options::Options()
+    : comparator(BytewiseComparator()),
+      create_if_missing(false),
+      error_if_exists(false),
+      paranoid_checks(false),
+      env(Env::Default()),
+      info_log(NULL),
+      write_buffer_size(4<<20),
+      max_open_files(1000),
+      block_cache(NULL),
+      block_size(4096),
+      block_restart_interval(16),
+      compression(kSnappyCompression),
+      filter_policy(NULL) {
+}
+
+
+}  // namespace leveldb
diff --git a/src/leveldb/util/posix_logger.h b/src/leveldb/util/posix_logger.h
new file mode 100644
index 0000000000..9741b1afad
--- /dev/null
+++ b/src/leveldb/util/posix_logger.h
@@ -0,0 +1,98 @@
+// 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.
+//
+// Logger implementation that can be shared by all environments
+// where enough posix functionality is available.
+
+#ifndef STORAGE_LEVELDB_UTIL_POSIX_LOGGER_H_
+#define STORAGE_LEVELDB_UTIL_POSIX_LOGGER_H_
+
+#include <algorithm>
+#include <stdio.h>
+#include <sys/time.h>
+#include <time.h>
+#include "leveldb/env.h"
+
+namespace leveldb {
+
+class PosixLogger : public Logger {
+ private:
+  FILE* file_;
+  uint64_t (*gettid_)();  // Return the thread id for the current thread
+ public:
+  PosixLogger(FILE* f, uint64_t (*gettid)()) : file_(f), gettid_(gettid) { }
+  virtual ~PosixLogger() {
+    fclose(file_);
+  }
+  virtual void Logv(const char* format, va_list ap) {
+    const uint64_t thread_id = (*gettid_)();
+
+    // We try twice: the first time with a fixed-size stack allocated buffer,
+    // and the second time with a much larger dynamically allocated buffer.
+    char buffer[500];
+    for (int iter = 0; iter < 2; iter++) {
+      char* base;
+      int bufsize;
+      if (iter == 0) {
+        bufsize = sizeof(buffer);
+        base = buffer;
+      } else {
+        bufsize = 30000;
+        base = new char[bufsize];
+      }
+      char* p = base;
+      char* limit = base + bufsize;
+
+      struct timeval now_tv;
+      gettimeofday(&now_tv, NULL);
+      const time_t seconds = now_tv.tv_sec;
+      struct tm t;
+      localtime_r(&seconds, &t);
+      p += snprintf(p, limit - p,
+                    "%04d/%02d/%02d-%02d:%02d:%02d.%06d %llx ",
+                    t.tm_year + 1900,
+                    t.tm_mon + 1,
+                    t.tm_mday,
+                    t.tm_hour,
+                    t.tm_min,
+                    t.tm_sec,
+                    static_cast<int>(now_tv.tv_usec),
+                    static_cast<long long unsigned int>(thread_id));
+
+      // Print the message
+      if (p < limit) {
+        va_list backup_ap;
+        va_copy(backup_ap, ap);
+        p += vsnprintf(p, limit - p, format, backup_ap);
+        va_end(backup_ap);
+      }
+
+      // Truncate to available space if necessary
+      if (p >= limit) {
+        if (iter == 0) {
+          continue;       // Try again with larger buffer
+        } else {
+          p = limit - 1;
+        }
+      }
+
+      // Add newline if necessary
+      if (p == base || p[-1] != '\n') {
+        *p++ = '\n';
+      }
+
+      assert(p <= limit);
+      fwrite(base, 1, p - base, file_);
+      fflush(file_);
+      if (base != buffer) {
+        delete[] base;
+      }
+      break;
+    }
+  }
+};
+
+}  // namespace leveldb
+
+#endif  // STORAGE_LEVELDB_UTIL_POSIX_LOGGER_H_
diff --git a/src/leveldb/util/random.h b/src/leveldb/util/random.h
new file mode 100644
index 0000000000..07538242ea
--- /dev/null
+++ b/src/leveldb/util/random.h
@@ -0,0 +1,59 @@
+// 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.
+
+#ifndef STORAGE_LEVELDB_UTIL_RANDOM_H_
+#define STORAGE_LEVELDB_UTIL_RANDOM_H_
+
+#include <stdint.h>
+
+namespace leveldb {
+
+// A very simple random number generator.  Not especially good at
+// generating truly random bits, but good enough for our needs in this
+// package.
+class Random {
+ private:
+  uint32_t seed_;
+ public:
+  explicit Random(uint32_t s) : seed_(s & 0x7fffffffu) { }
+  uint32_t Next() {
+    static const uint32_t M = 2147483647L;   // 2^31-1
+    static const uint64_t A = 16807;  // bits 14, 8, 7, 5, 2, 1, 0
+    // We are computing
+    //       seed_ = (seed_ * A) % M,    where M = 2^31-1
+    //
+    // seed_ must not be zero or M, or else all subsequent computed values
+    // will be zero or M respectively.  For all other values, seed_ will end
+    // up cycling through every number in [1,M-1]
+    uint64_t product = seed_ * A;
+
+    // Compute (product % M) using the fact that ((x << 31) % M) == x.
+    seed_ = static_cast<uint32_t>((product >> 31) + (product & M));
+    // The first reduction may overflow by 1 bit, so we may need to
+    // repeat.  mod == M is not possible; using > allows the faster
+    // sign-bit-based test.
+    if (seed_ > M) {
+      seed_ -= M;
+    }
+    return seed_;
+  }
+  // Returns a uniformly distributed value in the range [0..n-1]
+  // REQUIRES: n > 0
+  uint32_t Uniform(int n) { return Next() % n; }
+
+  // Randomly returns true ~"1/n" of the time, and false otherwise.
+  // REQUIRES: n > 0
+  bool OneIn(int n) { return (Next() % n) == 0; }
+
+  // Skewed: pick "base" uniformly from range [0,max_log] and then
+  // return "base" random bits.  The effect is to pick a number in the
+  // range [0,2^max_log-1] with exponential bias towards smaller numbers.
+  uint32_t Skewed(int max_log) {
+    return Uniform(1 << Uniform(max_log + 1));
+  }
+};
+
+}  // namespace leveldb
+
+#endif  // STORAGE_LEVELDB_UTIL_RANDOM_H_
diff --git a/src/leveldb/util/status.cc b/src/leveldb/util/status.cc
new file mode 100644
index 0000000000..a44f35b314
--- /dev/null
+++ b/src/leveldb/util/status.cc
@@ -0,0 +1,75 @@
+// 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.
+
+#include <stdio.h>
+#include "port/port.h"
+#include "leveldb/status.h"
+
+namespace leveldb {
+
+const char* Status::CopyState(const char* state) {
+  uint32_t size;
+  memcpy(&size, state, sizeof(size));
+  char* result = new char[size + 5];
+  memcpy(result, state, size + 5);
+  return result;
+}
+
+Status::Status(Code code, const Slice& msg, const Slice& msg2) {
+  assert(code != kOk);
+  const uint32_t len1 = msg.size();
+  const uint32_t len2 = msg2.size();
+  const uint32_t size = len1 + (len2 ? (2 + len2) : 0);
+  char* result = new char[size + 5];
+  memcpy(result, &size, sizeof(size));
+  result[4] = static_cast<char>(code);
+  memcpy(result + 5, msg.data(), len1);
+  if (len2) {
+    result[5 + len1] = ':';
+    result[6 + len1] = ' ';
+    memcpy(result + 7 + len1, msg2.data(), len2);
+  }
+  state_ = result;
+}
+
+std::string Status::ToString() const {
+  if (state_ == NULL) {
+    return "OK";
+  } else {
+    char tmp[30];
+    const char* type;
+    switch (code()) {
+      case kOk:
+        type = "OK";
+        break;
+      case kNotFound:
+        type = "NotFound: ";
+        break;
+      case kCorruption:
+        type = "Corruption: ";
+        break;
+      case kNotSupported:
+        type = "Not implemented: ";
+        break;
+      case kInvalidArgument:
+        type = "Invalid argument: ";
+        break;
+      case kIOError:
+        type = "IO error: ";
+        break;
+      default:
+        snprintf(tmp, sizeof(tmp), "Unknown code(%d): ",
+                 static_cast<int>(code()));
+        type = tmp;
+        break;
+    }
+    std::string result(type);
+    uint32_t length;
+    memcpy(&length, state_, sizeof(length));
+    result.append(state_ + 5, length);
+    return result;
+  }
+}
+
+}  // namespace leveldb
diff --git a/src/leveldb/util/testharness.cc b/src/leveldb/util/testharness.cc
new file mode 100644
index 0000000000..eb1bdd554a
--- /dev/null
+++ b/src/leveldb/util/testharness.cc
@@ -0,0 +1,77 @@
+// 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.
+
+#include "util/testharness.h"
+
+#include <string>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+namespace leveldb {
+namespace test {
+
+namespace {
+struct Test {
+  const char* base;
+  const char* name;
+  void (*func)();
+};
+std::vector<Test>* tests;
+}
+
+bool RegisterTest(const char* base, const char* name, void (*func)()) {
+  if (tests == NULL) {
+    tests = new std::vector<Test>;
+  }
+  Test t;
+  t.base = base;
+  t.name = name;
+  t.func = func;
+  tests->push_back(t);
+  return true;
+}
+
+int RunAllTests() {
+  const char* matcher = getenv("LEVELDB_TESTS");
+
+  int num = 0;
+  if (tests != NULL) {
+    for (int i = 0; i < tests->size(); i++) {
+      const Test& t = (*tests)[i];
+      if (matcher != NULL) {
+        std::string name = t.base;
+        name.push_back('.');
+        name.append(t.name);
+        if (strstr(name.c_str(), matcher) == NULL) {
+          continue;
+        }
+      }
+      fprintf(stderr, "==== Test %s.%s\n", t.base, t.name);
+      (*t.func)();
+      ++num;
+    }
+  }
+  fprintf(stderr, "==== PASSED %d tests\n", num);
+  return 0;
+}
+
+std::string TmpDir() {
+  std::string dir;
+  Status s = Env::Default()->GetTestDirectory(&dir);
+  ASSERT_TRUE(s.ok()) << s.ToString();
+  return dir;
+}
+
+int RandomSeed() {
+  const char* env = getenv("TEST_RANDOM_SEED");
+  int result = (env != NULL ? atoi(env) : 301);
+  if (result <= 0) {
+    result = 301;
+  }
+  return result;
+}
+
+}  // namespace test
+}  // namespace leveldb
diff --git a/src/leveldb/util/testharness.h b/src/leveldb/util/testharness.h
new file mode 100644
index 0000000000..da4fe68bb4
--- /dev/null
+++ b/src/leveldb/util/testharness.h
@@ -0,0 +1,138 @@
+// 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.
+
+#ifndef STORAGE_LEVELDB_UTIL_TESTHARNESS_H_
+#define STORAGE_LEVELDB_UTIL_TESTHARNESS_H_
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <sstream>
+#include "leveldb/env.h"
+#include "leveldb/slice.h"
+#include "util/random.h"
+
+namespace leveldb {
+namespace test {
+
+// Run some of the tests registered by the TEST() macro.  If the
+// environment variable "LEVELDB_TESTS" is not set, runs all tests.
+// Otherwise, runs only the tests whose name contains the value of
+// "LEVELDB_TESTS" as a substring.  E.g., suppose the tests are:
+//    TEST(Foo, Hello) { ... }
+//    TEST(Foo, World) { ... }
+// LEVELDB_TESTS=Hello will run the first test
+// LEVELDB_TESTS=o     will run both tests
+// LEVELDB_TESTS=Junk  will run no tests
+//
+// Returns 0 if all tests pass.
+// Dies or returns a non-zero value if some test fails.
+extern int RunAllTests();
+
+// Return the directory to use for temporary storage.
+extern std::string TmpDir();
+
+// Return a randomization seed for this run.  Typically returns the
+// same number on repeated invocations of this binary, but automated
+// runs may be able to vary the seed.
+extern int RandomSeed();
+
+// An instance of Tester is allocated to hold temporary state during
+// the execution of an assertion.
+class Tester {
+ private:
+  bool ok_;
+  const char* fname_;
+  int line_;
+  std::stringstream ss_;
+
+ public:
+  Tester(const char* f, int l)
+      : ok_(true), fname_(f), line_(l) {
+  }
+
+  ~Tester() {
+    if (!ok_) {
+      fprintf(stderr, "%s:%d:%s\n", fname_, line_, ss_.str().c_str());
+      exit(1);
+    }
+  }
+
+  Tester& Is(bool b, const char* msg) {
+    if (!b) {
+      ss_ << " Assertion failure " << msg;
+      ok_ = false;
+    }
+    return *this;
+  }
+
+  Tester& IsOk(const Status& s) {
+    if (!s.ok()) {
+      ss_ << " " << s.ToString();
+      ok_ = false;
+    }
+    return *this;
+  }
+
+#define BINARY_OP(name,op)                              \
+  template <class X, class Y>                           \
+  Tester& name(const X& x, const Y& y) {                \
+    if (! (x op y)) {                                   \
+      ss_ << " failed: " << x << (" " #op " ") << y;    \
+      ok_ = false;                                      \
+    }                                                   \
+    return *this;                                       \
+  }
+
+  BINARY_OP(IsEq, ==)
+  BINARY_OP(IsNe, !=)
+  BINARY_OP(IsGe, >=)
+  BINARY_OP(IsGt, >)
+  BINARY_OP(IsLe, <=)
+  BINARY_OP(IsLt, <)
+#undef BINARY_OP
+
+  // Attach the specified value to the error message if an error has occurred
+  template <class V>
+  Tester& operator<<(const V& value) {
+    if (!ok_) {
+      ss_ << " " << value;
+    }
+    return *this;
+  }
+};
+
+#define ASSERT_TRUE(c) ::leveldb::test::Tester(__FILE__, __LINE__).Is((c), #c)
+#define ASSERT_OK(s) ::leveldb::test::Tester(__FILE__, __LINE__).IsOk((s))
+#define ASSERT_EQ(a,b) ::leveldb::test::Tester(__FILE__, __LINE__).IsEq((a),(b))
+#define ASSERT_NE(a,b) ::leveldb::test::Tester(__FILE__, __LINE__).IsNe((a),(b))
+#define ASSERT_GE(a,b) ::leveldb::test::Tester(__FILE__, __LINE__).IsGe((a),(b))
+#define ASSERT_GT(a,b) ::leveldb::test::Tester(__FILE__, __LINE__).IsGt((a),(b))
+#define ASSERT_LE(a,b) ::leveldb::test::Tester(__FILE__, __LINE__).IsLe((a),(b))
+#define ASSERT_LT(a,b) ::leveldb::test::Tester(__FILE__, __LINE__).IsLt((a),(b))
+
+#define TCONCAT(a,b) TCONCAT1(a,b)
+#define TCONCAT1(a,b) a##b
+
+#define TEST(base,name)                                                 \
+class TCONCAT(_Test_,name) : public base {                              \
+ public:                                                                \
+  void _Run();                                                          \
+  static void _RunIt() {                                                \
+    TCONCAT(_Test_,name) t;                                             \
+    t._Run();                                                           \
+  }                                                                     \
+};                                                                      \
+bool TCONCAT(_Test_ignored_,name) =                                     \
+  ::leveldb::test::RegisterTest(#base, #name, &TCONCAT(_Test_,name)::_RunIt); \
+void TCONCAT(_Test_,name)::_Run()
+
+// Register the specified test.  Typically not used directly, but
+// invoked via the macro expansion of TEST.
+extern bool RegisterTest(const char* base, const char* name, void (*func)());
+
+
+}  // namespace test
+}  // namespace leveldb
+
+#endif  // STORAGE_LEVELDB_UTIL_TESTHARNESS_H_
diff --git a/src/leveldb/util/testutil.cc b/src/leveldb/util/testutil.cc
new file mode 100644
index 0000000000..538d09516d
--- /dev/null
+++ b/src/leveldb/util/testutil.cc
@@ -0,0 +1,51 @@
+// 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.
+
+#include "util/testutil.h"
+
+#include "util/random.h"
+
+namespace leveldb {
+namespace test {
+
+Slice RandomString(Random* rnd, int len, std::string* dst) {
+  dst->resize(len);
+  for (int i = 0; i < len; i++) {
+    (*dst)[i] = static_cast<char>(' ' + rnd->Uniform(95));   // ' ' .. '~'
+  }
+  return Slice(*dst);
+}
+
+std::string RandomKey(Random* rnd, int len) {
+  // Make sure to generate a wide variety of characters so we
+  // test the boundary conditions for short-key optimizations.
+  static const char kTestChars[] = {
+    '\0', '\1', 'a', 'b', 'c', 'd', 'e', '\xfd', '\xfe', '\xff'
+  };
+  std::string result;
+  for (int i = 0; i < len; i++) {
+    result += kTestChars[rnd->Uniform(sizeof(kTestChars))];
+  }
+  return result;
+}
+
+
+extern Slice CompressibleString(Random* rnd, double compressed_fraction,
+                                int len, std::string* dst) {
+  int raw = static_cast<int>(len * compressed_fraction);
+  if (raw < 1) raw = 1;
+  std::string raw_data;
+  RandomString(rnd, raw, &raw_data);
+
+  // Duplicate the random data until we have filled "len" bytes
+  dst->clear();
+  while (dst->size() < len) {
+    dst->append(raw_data);
+  }
+  dst->resize(len);
+  return Slice(*dst);
+}
+
+}  // namespace test
+}  // namespace leveldb
diff --git a/src/leveldb/util/testutil.h b/src/leveldb/util/testutil.h
new file mode 100644
index 0000000000..824e655bd2
--- /dev/null
+++ b/src/leveldb/util/testutil.h
@@ -0,0 +1,53 @@
+// 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.
+
+#ifndef STORAGE_LEVELDB_UTIL_TESTUTIL_H_
+#define STORAGE_LEVELDB_UTIL_TESTUTIL_H_
+
+#include "leveldb/env.h"
+#include "leveldb/slice.h"
+#include "util/random.h"
+
+namespace leveldb {
+namespace test {
+
+// Store in *dst a random string of length "len" and return a Slice that
+// references the generated data.
+extern Slice RandomString(Random* rnd, int len, std::string* dst);
+
+// Return a random key with the specified length that may contain interesting
+// characters (e.g. \x00, \xff, etc.).
+extern std::string RandomKey(Random* rnd, int len);
+
+// Store in *dst a string of length "len" that will compress to
+// "N*compressed_fraction" bytes and return a Slice that references
+// the generated data.
+extern Slice CompressibleString(Random* rnd, double compressed_fraction,
+                                int len, std::string* dst);
+
+// A wrapper that allows injection of errors.
+class ErrorEnv : public EnvWrapper {
+ public:
+  bool writable_file_error_;
+  int num_writable_file_errors_;
+
+  ErrorEnv() : EnvWrapper(Env::Default()),
+               writable_file_error_(false),
+               num_writable_file_errors_(0) { }
+
+  virtual Status NewWritableFile(const std::string& fname,
+                                 WritableFile** result) {
+    if (writable_file_error_) {
+      ++num_writable_file_errors_;
+      *result = NULL;
+      return Status::IOError(fname, "fake error");
+    }
+    return target()->NewWritableFile(fname, result);
+  }
+};
+
+}  // namespace test
+}  // namespace leveldb
+
+#endif  // STORAGE_LEVELDB_UTIL_TESTUTIL_H_