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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;
}
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 (user_comparator_->Compare(*start, tmp) < 0) {
// User key has become larger. 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 (user_comparator_->Compare(user_key, tmp) < 0) {
// User key has become larger. 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);
}
}
LargeValueRef LargeValueRef::Make(const Slice& value, CompressionType ctype) {
LargeValueRef result;
port::SHA1_Hash(value.data(), value.size(), &result.data[0]);
EncodeFixed64(&result.data[20], value.size());
result.data[28] = static_cast<unsigned char>(ctype);
return result;
}
std::string LargeValueRefToFilenameString(const LargeValueRef& h) {
assert(sizeof(h.data) == LargeValueRef::ByteSize());
assert(sizeof(h.data) == 29); // So we can hardcode the array size of buf
static const char tohex[] = "0123456789abcdef";
char buf[20*2];
for (int i = 0; i < 20; i++) {
buf[2*i] = tohex[(h.data[i] >> 4) & 0xf];
buf[2*i+1] = tohex[h.data[i] & 0xf];
}
std::string result = std::string(buf, sizeof(buf));
result += "-";
result += NumberToString(h.ValueSize());
result += "-";
result += NumberToString(static_cast<uint64_t>(h.compression_type()));
return result;
}
static uint32_t hexvalue(char c) {
if (c >= '0' && c <= '9') {
return c - '0';
} else if (c >= 'A' && c <= 'F') {
return 10 + c - 'A';
} else {
assert(c >= 'a' && c <= 'f');
return 10 + c - 'a';
}
}
bool FilenameStringToLargeValueRef(const Slice& s, LargeValueRef* h) {
Slice in = s;
if (in.size() < 40) {
return false;
}
for (int i = 0; i < 20; i++) {
if (!isxdigit(in[i*2]) || !isxdigit(in[i*2+1])) {
return false;
}
unsigned char c = (hexvalue(in[i*2])<<4) | hexvalue(in[i*2+1]);
h->data[i] = c;
}
in.remove_prefix(40);
uint64_t value_size, ctype;
if (ConsumeChar(&in, '-') &&
ConsumeDecimalNumber(&in, &value_size) &&
ConsumeChar(&in, '-') &&
ConsumeDecimalNumber(&in, &ctype) &&
in.empty() &&
(ctype <= kSnappyCompression)) {
EncodeFixed64(&h->data[20], value_size);
h->data[28] = static_cast<unsigned char>(ctype);
return true;
} else {
return false;
}
}
}
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