#pragma once
#include <string>
#include <iostream>
#include <cassert>
#include <limits>
#include "../include/typedefs.h"
#include "../include/DataTypeReader.h"
#include "../include/DataTypeReader.h"
#include "format.h"
namespace relpipe {
namespace reader {
/**
* The prototype does not have various integer and other numeric data types,
* it just works with one type of integer.
* But this integer has variable length -- smaller values occupy only one byte, bigger ones, more bytes 1,2,4,8 + first byte (contains length signalization).
* In the real implementation of relational pipes, there will be DataTypes for particular numeric types.
*
* TODO: support also big endian architectures.
* TODO: throw exception if a value was stored in bigger type than needed (while reading – there should be only one supported way how to encode a single value)
*
* Example of encoded values:
* -------------------------------------------------------------------------------------------------
* $ for n in 0 1 10 250 251 252 65535 65536 4294967295 4294967296 18446744073709551615; do printf '%20s = ' $n; dist/Debug/GNU-Linux/rp-prototype write integer $n | hd | head -n 1; done
* 0 = 00000000 00 |.|
* 1 = 00000000 01 |.|
* 10 = 00000000 0a |.|
* 250 = 00000000 fa |.|
* 251 = 00000000 fb fb |..|
* 252 = 00000000 fb fc |..|
* 65535 = 00000000 fc ff ff |...|
* 65536 = 00000000 fd 00 00 01 00 |.....|
* 4294967295 = 00000000 fd ff ff ff ff |.....|
* 4294967296 = 00000000 fe 00 00 00 00 01 00 00 00 |.........|
* 18446744073709551615 = 00000000 fe ff ff ff ff ff ff ff ff |.........|
* -------------------------------------------------------------------------------------------------
*
* Example of decoded values:
* -------------------------------------------------------------------------------------------------
* $ for n in 0 1 10 250 251 252 65535 65536 4294967295 4294967296 18446744073709551615; do dist/Debug/GNU-Linux/rp-prototype write integer $n | dist/Debug/GNU-Linux/rp-prototype read integer; done;
* 0
* 1
* 10
* 250
* 251
* 252
* 65535
* 65536
* 4294967295
* 4294967296
* 18446744073709551615
* -------------------------------------------------------------------------------------------------
*
* Note: similar format as original idea: https://en.wikipedia.org/wiki/X.690#Length_octets
*
*/
class IntegerDataTypeReader : public DataTypeReader<integer_t> {
private:
static const uint8_t INTEGER_TYPE_UINT8 = 251;
static const uint8_t INTEGER_TYPE_UINT16 = 252;
static const uint8_t INTEGER_TYPE_UINT32 = 253;
static const uint8_t INTEGER_TYPE_UINT64 = 254;
static const uint8_t INTEGER_TYPE_RESERVED = 255;
template<typename T> integer_t read(std::istream &input) {
T value = 0;
input.read(reinterpret_cast<char *> (&value), sizeof (value));
return value;
}
public:
IntegerDataTypeReader() : DataTypeReader<integer_t>(DATA_TYPE_ID_INTEGER, DATA_TYPE_CODE_INTEGER) {
}
integer_t readValue(std::istream &input) override {
uint8_t first;
input.read(reinterpret_cast<char *> (&first), sizeof (first));
if (input.good()) {
if (first < INTEGER_TYPE_UINT8) return first;
else if (first == INTEGER_TYPE_UINT8) return read<uint8_t>(input);
else if (first == INTEGER_TYPE_UINT16) return read<uint16_t>(input);
else if (first == INTEGER_TYPE_UINT32) return read<uint32_t>(input);
else if (first == INTEGER_TYPE_UINT64) return read<uint64_t>(input);
else throw RelpipeReaderException(L"Error while parsing integer type: unsupported type");
} else {
throw RelpipeReaderException(L"Error while reading integer from the stream.");
}
}
string_t toString(const integer_t &value) override {
return std::to_wstring(value);
}
};
}
}