#pragma once
#include <string>
#include <iostream>
#include <cassert>
#include <limits>
#include "../DataTypeWriter.h"
#include "../format.h"
namespace relpipe {
namespace writer {
namespace types {
using namespace relpipe::writer;
/**
* 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 IntegerDataTypeWriter : public DataTypeWriter<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> void write(std::ostream &output, const integer_t &value) {
assert(sizeof (T) <= sizeof (value));
output.write(reinterpret_cast<const char *> (&value), sizeof (T));
}
template<typename T> void write(std::ostream &output, const uint8_t type, const integer_t &value) {
write<uint8_t>(output, type);
write<T>(output, value);
}
template<typename T> bool fits(const integer_t &value) {
return value <= numeric_limits<T>::max();
}
public:
IntegerDataTypeWriter() : DataTypeWriter<integer_t>(TypeId::INTEGER, DATA_TYPE_CODE_INTEGER) {
}
void writeValue(std::ostream &output, const integer_t &value) override {
// output << value; // by zapsalo číslo jako ASII text
if (value < INTEGER_TYPE_UINT8) write<uint8_t>(output, value);
else if (fits<uint8_t>(value)) write<uint8_t>(output, INTEGER_TYPE_UINT8, value);
else if (fits<uint16_t>(value)) write<uint16_t>(output, INTEGER_TYPE_UINT16, value);
else if (fits<uint32_t>(value)) write<uint32_t>(output, INTEGER_TYPE_UINT32, value);
else if (fits<uint64_t>(value)) write<uint64_t>(output, INTEGER_TYPE_UINT64, value);
else throw RelpipeWriterException(L"Error while writing integer type: value too long");
}
integer_t toValue(const string_t &stringValue) override {
// throws „terminate called after throwing an instance of 'std::invalid_argument'“ SIGABRT, core dumped on invalid number
return stoul(stringValue);
}
};
}
}
}