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-rw-r--r--src/leveldb/db/dbformat.cc140
1 files changed, 140 insertions, 0 deletions
diff --git a/src/leveldb/db/dbformat.cc b/src/leveldb/db/dbformat.cc
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index 0000000000..28e11b398d
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+++ b/src/leveldb/db/dbformat.cc
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+// 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 "db/dbformat.h"
+#include "port/port.h"
+#include "util/coding.h"
+
+namespace leveldb {
+
+static uint64_t PackSequenceAndType(uint64_t seq, ValueType t) {
+ assert(seq <= kMaxSequenceNumber);
+ assert(t <= kValueTypeForSeek);
+ return (seq << 8) | t;
+}
+
+void AppendInternalKey(std::string* result, const ParsedInternalKey& key) {
+ result->append(key.user_key.data(), key.user_key.size());
+ PutFixed64(result, PackSequenceAndType(key.sequence, key.type));
+}
+
+std::string ParsedInternalKey::DebugString() const {
+ char buf[50];
+ snprintf(buf, sizeof(buf), "' @ %llu : %d",
+ (unsigned long long) sequence,
+ int(type));
+ std::string result = "'";
+ result += user_key.ToString();
+ result += buf;
+ return result;
+}
+
+std::string InternalKey::DebugString() const {
+ std::string result;
+ ParsedInternalKey parsed;
+ if (ParseInternalKey(rep_, &parsed)) {
+ result = parsed.DebugString();
+ } else {
+ result = "(bad)";
+ result.append(EscapeString(rep_));
+ }
+ return result;
+}
+
+const char* InternalKeyComparator::Name() const {
+ return "leveldb.InternalKeyComparator";
+}
+
+int InternalKeyComparator::Compare(const Slice& akey, const Slice& bkey) const {
+ // Order by:
+ // increasing user key (according to user-supplied comparator)
+ // decreasing sequence number
+ // decreasing type (though sequence# should be enough to disambiguate)
+ int r = user_comparator_->Compare(ExtractUserKey(akey), ExtractUserKey(bkey));
+ if (r == 0) {
+ const uint64_t anum = DecodeFixed64(akey.data() + akey.size() - 8);
+ const uint64_t bnum = DecodeFixed64(bkey.data() + bkey.size() - 8);
+ if (anum > bnum) {
+ r = -1;
+ } else if (anum < bnum) {
+ r = +1;
+ }
+ }
+ return r;
+}
+
+void InternalKeyComparator::FindShortestSeparator(
+ std::string* start,
+ const Slice& limit) const {
+ // Attempt to shorten the user portion of the key
+ Slice user_start = ExtractUserKey(*start);
+ Slice user_limit = ExtractUserKey(limit);
+ std::string tmp(user_start.data(), user_start.size());
+ user_comparator_->FindShortestSeparator(&tmp, user_limit);
+ if (tmp.size() < user_start.size() &&
+ user_comparator_->Compare(user_start, tmp) < 0) {
+ // User key has become shorter physically, but larger logically.
+ // Tack on the earliest possible number to the shortened user key.
+ PutFixed64(&tmp, PackSequenceAndType(kMaxSequenceNumber,kValueTypeForSeek));
+ assert(this->Compare(*start, tmp) < 0);
+ assert(this->Compare(tmp, limit) < 0);
+ start->swap(tmp);
+ }
+}
+
+void InternalKeyComparator::FindShortSuccessor(std::string* key) const {
+ Slice user_key = ExtractUserKey(*key);
+ std::string tmp(user_key.data(), user_key.size());
+ user_comparator_->FindShortSuccessor(&tmp);
+ if (tmp.size() < user_key.size() &&
+ user_comparator_->Compare(user_key, tmp) < 0) {
+ // User key has become shorter physically, but larger logically.
+ // Tack on the earliest possible number to the shortened user key.
+ PutFixed64(&tmp, PackSequenceAndType(kMaxSequenceNumber,kValueTypeForSeek));
+ assert(this->Compare(*key, tmp) < 0);
+ key->swap(tmp);
+ }
+}
+
+const char* InternalFilterPolicy::Name() const {
+ return user_policy_->Name();
+}
+
+void InternalFilterPolicy::CreateFilter(const Slice* keys, int n,
+ std::string* dst) const {
+ // We rely on the fact that the code in table.cc does not mind us
+ // adjusting keys[].
+ Slice* mkey = const_cast<Slice*>(keys);
+ for (int i = 0; i < n; i++) {
+ mkey[i] = ExtractUserKey(keys[i]);
+ // TODO(sanjay): Suppress dups?
+ }
+ user_policy_->CreateFilter(keys, n, dst);
+}
+
+bool InternalFilterPolicy::KeyMayMatch(const Slice& key, const Slice& f) const {
+ return user_policy_->KeyMayMatch(ExtractUserKey(key), f);
+}
+
+LookupKey::LookupKey(const Slice& user_key, SequenceNumber s) {
+ size_t usize = user_key.size();
+ size_t needed = usize + 13; // A conservative estimate
+ char* dst;
+ if (needed <= sizeof(space_)) {
+ dst = space_;
+ } else {
+ dst = new char[needed];
+ }
+ start_ = dst;
+ dst = EncodeVarint32(dst, usize + 8);
+ kstart_ = dst;
+ memcpy(dst, user_key.data(), usize);
+ dst += usize;
+ EncodeFixed64(dst, PackSequenceAndType(s, kValueTypeForSeek));
+ dst += 8;
+ end_ = dst;
+}
+
+} // namespace leveldb