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code style fix in APILengthCoDec

pull/33/head
Paul Rock 6 years ago
parent
e5992edb04
commit
c7130effd0
1 changed files with 59 additions and 62 deletions
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  1. 121
      src/APILengthCoDec.php

121
src/APILengthCoDec.php
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@ -19,37 +19,38 @@ class APILengthCoDec
/**
* Encode string to length of string
*
* Encode the length :
- if length <= 0x7F (binary : 01111111 => 7 bits set to 1)
- encode length with one byte
- set the byte to length value, as length maximal value is 7 bits set to 1, the most significant bit is always 0
- end
- length <= 0x3FFF (binary : 00111111 11111111 => 14 bits set to 1)
- encode length with two bytes
- set length value to 0x8000 (=> 10000000 00000000)
- add length : as length maximumal value is 14 bits to 1, this does not modify the 2 most significance bits (10)
- end
=> minimal encoded value is 10000000 10000000
- length <= 0x1FFFFF (binary : 00011111 11111111 11111111 => 21 bits set to 1)
- encode length with three bytes
- set length value to 0xC00000 (binary : 11000000 00000000 00000000)
- add length : as length maximal value is 21 bits to 1, this does not modify the 3 most significance bits (110)
- end
=> minimal encoded value is 11000000 01000000 00000000
- length <= 0x0FFFFFFF (binary : 00001111 11111111 11111111 11111111 => 28 bits set to 1)
- encode length with four bytes
- set length value to 0xE0000000 (binary : 11100000 00000000 00000000 00000000)
- add length : as length maximal value is 28 bits to 1, this does not modify the 4 most significance bits (1110)
- end
=> minimal encoded value is 11100000 00100000 00000000 00000000
- length <= 0x7FFFFFFFFF (binary : 00000111 11111111 11111111 11111111 11111111 => 35 bits set to 1)
- encode length with five bytes
- set length value to 0xF000000000 (binary : 11110000 00000000 00000000 00000000 00000000)
- add length : as length maximal value is 35 bits to 1, this does not modify the 5 most significance bits (11110)
- end
- length > 0x7FFFFFFFFF : not supported
* Encode the length:
* - if length <= 0x7F (binary : 01111111 => 7 bits set to 1)
* - encode length with one byte
* - set the byte to length value, as length maximal value is 7 bits set to 1, the most significant bit is always 0
* - end
* - length <= 0x3FFF (binary : 00111111 11111111 => 14 bits set to 1)
* - encode length with two bytes
* - set length value to 0x8000 (=> 10000000 00000000)
* - add length : as length maximumal value is 14 bits to 1, this does not modify the 2 most significance bits (10)
* - end
* => minimal encoded value is 10000000 10000000
* - length <= 0x1FFFFF (binary : 00011111 11111111 11111111 => 21 bits set to 1)
* - encode length with three bytes
* - set length value to 0xC00000 (binary : 11000000 00000000 00000000)
* - add length : as length maximal value is 21 bits to 1, this does not modify the 3 most significance bits (110)
* - end
* => minimal encoded value is 11000000 01000000 00000000
* - length <= 0x0FFFFFFF (binary : 00001111 11111111 11111111 11111111 => 28 bits set to 1)
* - encode length with four bytes
* - set length value to 0xE0000000 (binary : 11100000 00000000 00000000 00000000)
* - add length : as length maximal value is 28 bits to 1, this does not modify the 4 most significance bits (1110)
* - end
* => minimal encoded value is 11100000 00100000 00000000 00000000
* - length <= 0x7FFFFFFFFF (binary : 00000111 11111111 11111111 11111111 11111111 => 35 bits set to 1)
* - encode length with five bytes
* - set length value to 0xF000000000 (binary : 11110000 00000000 00000000 00000000 00000000)
* - add length : as length maximal value is 35 bits to 1, this does not modify the 5 most significance bits (11110)
* - end
* - length > 0x7FFFFFFFFF : not supported
*
* @param int|float $length
*
* @param int|float $length
* @return string
*/
public static function encodeLength($length): string
@ -79,39 +80,35 @@ class APILengthCoDec
return BinaryStringHelper::IntegerToNBOBinaryString(0xF000000000 + $length);
}
// Decode length of data when reading :
// The 5 firsts bits of the first byte specify how the length is encoded.
// The position of the first 0 value bit, starting from the most significant postion.
// - 0xxxxxxx => The 7 remainings bits of the first byte is the length :
// => min value of length is 0x00
// => max value of length is 0x7F (127 bytes)
// - 10xxxxxx => The 6 remainings bits of the first byte plus the next byte represent the lenght
// NOTE : the next byte MUST be at least 0x80 !!
// => min value of length is 0x80
// => max value of length is 0x3FFF (16,383 bytes, near 16 KB)
// - 110xxxxx => The 5 remainings bits of th first byte and the two next bytes represent the length
// => max value of length is 0x1FFFFF (2,097,151 bytes, near 2 MB)
// - 1110xxxx => The 4 remainings bits of the first byte and the three next bytes represent the length
// => max value of length is 0xFFFFFFF (268,435,455 bytes, near 270 MB)
// - 11110xxx => The 3 remainings bits of the first byte and the four next bytes represent the length
// => max value of length is 0x7FFFFFFF (2,147,483,647 byes, 2GB)
// - 11111xxx => This byte is not a length-encoded word but a control byte.
// => Extracted from Mikrotik API doc :
// it is a reserved control byte.
// After receiving unknown control byte API client cannot proceed, because it cannot know how to interpret following bytes
// Currently control bytes are not used
/**
* Decode length of data when reading :
* The 5 firsts bits of the first byte specify how the length is encoded.
* The position of the first 0 value bit, starting from the most significant postion.
* - 0xxxxxxx => The 7 remainings bits of the first byte is the length :
* => min value of length is 0x00
* => max value of length is 0x7F (127 bytes)
* - 10xxxxxx => The 6 remainings bits of the first byte plus the next byte represent the lenght
* NOTE : the next byte MUST be at least 0x80 !!
* => min value of length is 0x80
* => max value of length is 0x3FFF (16,383 bytes, near 16 KB)
* - 110xxxxx => The 5 remainings bits of th first byte and the two next bytes represent the length
* => max value of length is 0x1FFFFF (2,097,151 bytes, near 2 MB)
* - 1110xxxx => The 4 remainings bits of the first byte and the three next bytes represent the length
* => max value of length is 0xFFFFFFF (268,435,455 bytes, near 270 MB)
* - 11110xxx => The 3 remainings bits of the first byte and the four next bytes represent the length
* => max value of length is 0x7FFFFFFF (2,147,483,647 byes, 2GB)
* - 11111xxx => This byte is not a length-encoded word but a control byte.
* => Extracted from Mikrotik API doc:
* it is a reserved control byte.
* After receiving unknown control byte API client cannot proceed, because it cannot know how to interpret following bytes
* Currently control bytes are not used
*
* @param \RouterOS\Interfaces\StreamInterface $stream
*
* @return int
*/
public static function decodeLength(StreamInterface $stream): int
{
// if (false === is_resource($stream)) {
// throw new \InvalidArgumentException(
// sprintf(
// 'Argument must be a stream resource type. %s given.',
// gettype($stream)
// )
// );
// }
// Read first byte
$firstByte = ord($stream->read(1));
@ -191,7 +188,7 @@ class APILengthCoDec
}
// Now the only solution is 5 most significance bits are set to 1 (11111xxx)
// This is a control word, not implemented by Mikrotik for the moment
// This is a control word, not implemented by Mikrotik for the moment
throw new \UnexpectedValueException('Control Word found');
}
}
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