1-Wire: bitwise operations, matching mruby for compatibility

denko-rb · Oct 26, 2024 · 326b014 · 326b014
1 parent 7afc823
commit 326b014
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Showing 2 changed files with 8 additions and 11 deletions.
diff --git a/lib/denko/one_wire/bus_enumerator.rb b/lib/denko/one_wire/bus_enumerator.rb
@@ -44,17 +44,14 @@ def search
       def parse_search_result(result)
         address, complement = split_search_result(result)
 
-        if (address & complement) > 0
-          raise "OneWire device not connected or disconnected during search"
-        end
-
+        raise "OneWire device not connected, or disconnected during search" if (address & complement) > 0
         raise "CRC error during OneWire search" unless Helper.crc(address)
 
         # Gives 0 at every discrepancy we didn't write 1 for on this search.
         new_discrepancies = address ^ complement
 
         high_discrepancy = -1
-        (0..63).each { |i| high_discrepancy = i if new_discrepancies[i] == 0 }
+        (0..63).each { |i| high_discrepancy = i if ((new_discrepancies >> i) & 0b1 == 0) }
 
         # LSByte of address is product family.
         klass = family_lookup(address & 0xFF)
@@ -64,14 +61,12 @@ def parse_search_result(result)
 
       # Result is 16 bytes, 8 byte address and complement interleaved LSByte first.
       def split_search_result(data)
-        address = 0
+        address    = 0
         complement = 0
-
         data.reverse.each_slice(2) do |comp_byte, addr_byte|
-          address = (address << 8) | addr_byte
+          address    = (address << 8)    | addr_byte
           complement = (complement << 8) | comp_byte
         end
-
         [address, complement]
       end
 

diff --git a/lib/denko/one_wire/helper.rb b/lib/denko/one_wire/helper.rb
@@ -2,7 +2,9 @@ module Denko
   module OneWire
     class Helper
       def self.address_to_bytes(address)
-        [address].pack('Q<').split("").map(&:ord)
+        bytes = []
+        8.times { |i| bytes[i] = address >> (8*i) & 0xFF }
+        bytes
       end
 
       def self.crc(data)
@@ -20,7 +22,7 @@ def self.calculate_crc(data)
         crc = 0b00000000
         bytes.take(bytes.length - 1).each do |byte|
           for bit in (0..7)
-            xor = byte[bit] ^ crc[0]
+            xor = ((byte >> bit) & 0b1) ^ (crc & 0b1)
             crc = crc ^ ((xor * (2 ** 3)) | (xor * (2 ** 4)))
             crc = crc >> 1
             crc = crc | (xor * (2 ** 7))