Class: SpinelKit::Hex

Inherits:
Object
  • Object
show all
Defined in:
lib/spinel_kit/hex.rb

Class Method Summary collapse

Class Method Details

.byte2(n) ⇒ Object

Int byte 0..255 -> two-char LOWERCASE hex (15 -> “0f”). (JSON u00XX and similar use lowercase.)



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# File 'lib/spinel_kit/hex.rb', line 37

def self.byte2(n)
  hex = "0123456789abcdef"
  out = ""
  out = out + hex[(n / 16) % 16, 1]
  out = out + hex[n % 16, 1]
  out
end

.nibble(c) ⇒ Object

Hex digit char -> int 0..15, or -1 if not a hex digit (upper or lower).



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# File 'lib/spinel_kit/hex.rb', line 13

def self.nibble(c)
  if c >= "0" && c <= "9"
    return c.getbyte(0) - "0".getbyte(0)
  end
  if c >= "a" && c <= "f"
    return c.getbyte(0) - "a".getbyte(0) + 10
  end
  if c >= "A" && c <= "F"
    return c.getbyte(0) - "A".getbyte(0) + 10
  end
  -1
end

.nibble_char(n) ⇒ Object

Int nibble 0..15 -> single UPPERCASE hex char (“0”..“9”,“A”..“F”). (RFC 3986 percent-encoding uses uppercase.)



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# File 'lib/spinel_kit/hex.rb', line 28

def self.nibble_char(n)
  if n < 10
    return ("0".getbyte(0) + n).chr
  end
  ("A".getbyte(0) + n - 10).chr
end

.to_int(s) ⇒ Object

Parse the leading hex digits of ‘s` -> int (“1a3” -> 419). Stops at the first non-hex char; returns 0 if there is no leading hex digit. Useful for chunked-transfer sizes and the like.



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# File 'lib/spinel_kit/hex.rb', line 48

def self.to_int(s)
  n = 0
  i = 0
  len = s.length
  while i < len
    v = Hex.nibble(s[i])
    if v < 0
      return n
    end
    n = n * 16 + v
    i += 1
  end
  n
end