作者: 韩晨旭@ArcueidType(Arcueid) 10225101440 李畅@wesley 10225102463 设计文档为PLAN.md,md版本报告为README.md,pdf版本报告为Report.pdf
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#ifndef VTABLE_FORMAT_H
#define VTABLE_FORMAT_H
#include "leveldb/slice.h"
#include "leveldb/status.h"
#include "table/format.h"
namespace leveldb {
const uint64_t kRecordHeaderSize = 4;
struct VTableRecord {
Slice key;
Slice value;
void Encode(std::string* target) const;
Status Decode(Slice* input);
size_t size() const { return key.size() + value.size(); }
friend bool operator==(const VTableRecord& a, const VTableRecord& b) {
return a.key == b.key && a.value == b.value;
}
};
class RecordEncoder {
public:
// TODO: Support compression while encoding a record
RecordEncoder() = default;
// Encode a vTable record
void Encode(const VTableRecord& record);
// Get the size of encoded record
size_t GetEncodedSize() const { return sizeof(header_) + record_.size(); }
// Get the header
Slice GetHeader() const { return {header_, sizeof(header_)}; }
// Get the encoded record
Slice GetRecord() const {return record_; }
private:
char header_[kRecordHeaderSize];
Slice record_;
std::string record_buff_;
};
class RecordDecoder {
public:
Status DecodeHeader(Slice* input);
Status DecodeRecord(Slice* input, VTableRecord* record) const;
size_t GetDecodedSize() const { return record_size_; }
private:
uint32_t record_size_{0};
};
struct VTableHandle {
uint64_t offset{0};
uint64_t size{0};
void Encode(std::string* target) const;
Status Decode(Slice* input);
friend bool operator==(const VTableHandle& a, const VTableHandle& b) {
return a.offset == b.offset && a.size == b.size;
}
};
struct VTableIndex {
enum Type : unsigned char {
kVTableIndex = 1,
};
uint64_t file_number{0};
VTableHandle vtable_handle;
void Encode(std::string* target) const;
Status Decode(Slice* input);
friend bool operator==(const VTableIndex& a, const VTableIndex& b) {
return a.file_number == b.file_number && a.vtable_handle == b.vtable_handle;
}
};
template <typename T>
Status DecodeSrcIntoObj(const Slice& src, T* target) {
Slice input = src;
Status s = target->Decode(&input);
if (s.ok() && !input.empty()) {
s = Status::Corruption(Slice());
}
return s;
}
} // namespace leveldb
#endif //VTABLE_FORMAT_H