libcryfs/utils/FixedSizeData.h

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2015-04-09 20:07:03 +02:00
#pragma once
#ifndef BLOCKSTORE_UTILS_data_H_
#define BLOCKSTORE_UTILS_data_H_
#include <cryptopp/cryptopp/hex.h>
#include <cryptopp/cryptopp/osrng.h>
#include <string>
#include <cstring>
namespace blockstore {
template<int SIZE>
class FixedSizeData {
public:
//Non-virtual destructor because we want objects to be small
~FixedSizeData() {}
static constexpr unsigned int BINARY_LENGTH = SIZE;
static constexpr unsigned int STRING_LENGTH = 2 * BINARY_LENGTH; // Hex encoding
static FixedSizeData<SIZE> CreateRandom();
static FixedSizeData<SIZE> FromString(const std::string &data);
std::string ToString() const;
static FixedSizeData<SIZE> FromBinary(const void *source);
void ToBinary(void *target) const;
const unsigned char *data() const;
private:
FixedSizeData() {}
static CryptoPP::AutoSeededRandomPool &RandomPool();
unsigned char _data[BINARY_LENGTH];
};
template<int SIZE> bool operator==(const FixedSizeData<SIZE> &lhs, const FixedSizeData<SIZE> &rhs);
template<int SIZE> bool operator!=(const FixedSizeData<SIZE> &lhs, const FixedSizeData<SIZE> &rhs);
//operator< is defined, so that FixedSizeData objects can be used in std::map and std::set
template<int SIZE> bool operator<(const FixedSizeData<SIZE> &lhs, const FixedSizeData<SIZE> &rhs);
// ----- Implementation -----
template<int SIZE> constexpr unsigned int FixedSizeData<SIZE>::BINARY_LENGTH;
template<int SIZE> constexpr unsigned int FixedSizeData<SIZE>::STRING_LENGTH;
template<int SIZE>
CryptoPP::AutoSeededRandomPool &FixedSizeData<SIZE>::RandomPool() {
static CryptoPP::AutoSeededRandomPool singleton;
return singleton;
}
template<int SIZE>
FixedSizeData<SIZE> FixedSizeData<SIZE>::CreateRandom() {
FixedSizeData<SIZE> result;
RandomPool().GenerateBlock(result._data, BINARY_LENGTH);
return result;
}
template<int SIZE>
FixedSizeData<SIZE> FixedSizeData<SIZE>::FromString(const std::string &data) {
assert(data.size() == STRING_LENGTH);
FixedSizeData<SIZE> result;
CryptoPP::StringSource(data, true,
new CryptoPP::HexDecoder(
new CryptoPP::ArraySink(result._data, BINARY_LENGTH)
)
);
return result;
}
template<int SIZE>
std::string FixedSizeData<SIZE>::ToString() const {
std::string result;
CryptoPP::ArraySource(_data, BINARY_LENGTH, true,
new CryptoPP::HexEncoder(
new CryptoPP::StringSink(result)
)
);
assert(result.size() == STRING_LENGTH);
return result;
}
template<int SIZE>
const unsigned char *FixedSizeData<SIZE>::data() const {
return _data;
}
template<int SIZE>
void FixedSizeData<SIZE>::ToBinary(void *target) const {
std::memcpy(target, _data, BINARY_LENGTH);
}
template<int SIZE>
FixedSizeData<SIZE> FixedSizeData<SIZE>::FromBinary(const void *source) {
FixedSizeData<SIZE> result;
std::memcpy(result._data, source, BINARY_LENGTH);
return result;
}
template<int SIZE>
bool operator==(const FixedSizeData<SIZE> &lhs, const FixedSizeData<SIZE> &rhs) {
return 0 == std::memcmp(lhs.data(), rhs.data(), FixedSizeData<SIZE>::BINARY_LENGTH);
}
template<int SIZE>
bool operator!=(const FixedSizeData<SIZE> &lhs, const FixedSizeData<SIZE> &rhs) {
return !operator==(lhs, rhs);
}
template<int SIZE>
bool operator<(const FixedSizeData<SIZE> &lhs, const FixedSizeData<SIZE> &rhs) {
return 0 > std::memcmp(lhs.data(), rhs.data(), FixedSizeData<SIZE>::BINARY_LENGTH);
}
}
#endif