1 #pragma once

     2 

     3 #include <string>

     4 #include <iostream>

     5 #include <cassert>

     6 #include <limits>

     7 

     8 #include "../include/DataTypeWriter.h"

     9 #include "format.h"

    10 

    11 namespace relpipe {

    12 namespace writer {

    13 

    14 /**

    15  * The prototype does not have various integer and other numeric data types,

    16  * it just works with one type of integer.

    17  * 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).

    18  * In the real implementation of relational pipes, there will be DataTypes for particular numeric types.

    19  * 

    20  * TODO: support also big endian architectures.

    21  * 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)

    22  * 

    23  * Example of encoded values:

    24  * -------------------------------------------------------------------------------------------------

    25  * $ 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

    26  *                    0 = 00000000  00                                                |.|

    27  *                    1 = 00000000  01                                                |.|

    28  *                   10 = 00000000  0a                                                |.|

    29  *                  250 = 00000000  fa                                                |.|

    30  *                  251 = 00000000  fb fb                                             |..|

    31  *                  252 = 00000000  fb fc                                             |..|

    32  *                65535 = 00000000  fc ff ff                                          |...|

    33  *                65536 = 00000000  fd 00 00 01 00                                    |.....|

    34  *           4294967295 = 00000000  fd ff ff ff ff                                    |.....|

    35  *           4294967296 = 00000000  fe 00 00 00 00 01 00 00  00                       |.........|

    36  * 18446744073709551615 = 00000000  fe ff ff ff ff ff ff ff  ff                       |.........|

    37  * -------------------------------------------------------------------------------------------------

    38  * 

    39  * Example of decoded values:

    40  * -------------------------------------------------------------------------------------------------

    41  * $ 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;

    42  * 0

    43  * 1

    44  * 10

    45  * 250

    46  * 251

    47  * 252

    48  * 65535

    49  * 65536

    50  * 4294967295

    51  * 4294967296

    52  * 18446744073709551615

    53  * -------------------------------------------------------------------------------------------------

    54  * 

    55  * Note: similar format as original idea: https://en.wikipedia.org/wiki/X.690#Length_octets

    56  * 

    57  */

    58 class IntegerDataTypeWriter : public DataTypeWriter<integer_t> {

    59 private:

    60 	static const uint8_t INTEGER_TYPE_UINT8 = 251;

    61 	static const uint8_t INTEGER_TYPE_UINT16 = 252;

    62 	static const uint8_t INTEGER_TYPE_UINT32 = 253;

    63 	static const uint8_t INTEGER_TYPE_UINT64 = 254;

    64 	static const uint8_t INTEGER_TYPE_RESERVED = 255;

    65 

    66 	template<typename T> void write(std::ostream &output, const integer_t &value) {

    67 		assert(sizeof (T) <= sizeof (value));

    68 		output.write(reinterpret_cast<const char *> (&value), sizeof (T));

    69 	}

    70 

    71 	template<typename T> void write(std::ostream &output, const uint8_t type, const integer_t &value) {

    72 		write<uint8_t>(output, type);

    73 		write<T>(output, value);

    74 	}

    75 

    76 	template<typename T> bool fits(const integer_t &value) {

    77 		return value <= numeric_limits<T>::max();

    78 	}

    79 

    80 public:

    81 

    82 	IntegerDataTypeWriter() : DataTypeWriter<integer_t>(DATA_TYPE_ID_INTEGER, DATA_TYPE_CODE_INTEGER) {

    83 	}

    84 

    85 	void writeValue(std::ostream &output, const integer_t &value) override {

    86 		// output << value; // by zapsalo číslo jako ASII text

    87 

    88 		if (value < INTEGER_TYPE_UINT8) write<uint8_t>(output, value);

    89 		else if (fits<uint8_t>(value)) write<uint8_t>(output, INTEGER_TYPE_UINT8, value);

    90 		else if (fits<uint16_t>(value)) write<uint16_t>(output, INTEGER_TYPE_UINT16, value);

    91 		else if (fits<uint32_t>(value)) write<uint32_t>(output, INTEGER_TYPE_UINT32, value);

    92 		else if (fits<uint64_t>(value)) write<uint64_t>(output, INTEGER_TYPE_UINT64, value);

    93 		else throw RelpipeWriterException(L"Error while writing integer type: value too long");

    94 	}

    95 

    96 	integer_t toValue(const string_t &stringValue) override {

    97 		// throws „terminate called after throwing an instance of 'std::invalid_argument'“ SIGABRT, core dumped on invalid number

    98 		return stoul(stringValue);

    99 	}

   100 

   101 };

   102 

   103 }

   104 }