Rewrite/clean up bitarray

weichen0407 · Feb 16, 2021 · 2dacedf · 2dacedf
1 parent 2652506
commit 2dacedf
Showing 1 changed file with 5 additions and 74 deletions.
diff --git a/bitarray.py b/bitarray.py
@@ -1,85 +1,34 @@
-# Important!!!!!
-# This code is just ported and adapted from the decompiled minecraft source
-# This means it has questionable copyright
-# Maybe a re-write is in order?
+# The purpost of this class is to read the bitarray format that minecraft likes to store data in
 
 from math import floor
 
 def inclusiveBetween(start, end, value):
    if value < start or value > end:
-      raise ValueError("The value %i is not in the specified inclusive range of %i to %i" % (value, start, end))
+      raise ValueError("The value %i is not in the inclusive range of %i to %i" % (value, start, end))
 
-weirdArray = [-1, -1, 0, -2147483648, 0, 0, 1431655765, 1431655765, 0, -2147483648, 0, 1, 858993459, 858993459, 0, 715827882, 715827882, 0, 613566756, 613566756, 0, -2147483648, 0, 2, 477218588, 477218588, 0, 429496729, 429496729, 0, 390451572, 390451572, 0, 357913941, 357913941, 0, 330382099, 330382099, 0, 306783378, 306783378, 0, 286331153, 286331153, 0, -2147483648, 0, 3, 252645135, 252645135, 0, 238609294, 238609294, 0, 226050910, 226050910, 0, 214748364, 214748364, 0, 204522252, 204522252, 0, 195225786, 195225786, 0, 186737708, 186737708, 0, 178956970, 178956970, 0, 171798691, 171798691, 0, 165191049, 165191049, 0, 159072862, 159072862, 0, 153391689, 153391689, 0, 148102320, 148102320, 0, 143165576, 143165576, 0, 138547332, 138547332, 0, -2147483648, 0, 4, 130150524, 130150524, 0, 126322567, 126322567, 0, 122713351, 122713351, 0, 119304647, 119304647, 0, 116080197, 116080197, 0, 113025455, 113025455, 0, 110127366, 110127366, 0, 107374182, 107374182, 0, 104755299, 104755299, 0, 102261126, 102261126, 0, 99882960, 99882960, 0, 97612893, 97612893, 0, 95443717, 95443717, 0, 93368854, 93368854, 0, 91382282, 91382282, 0, 89478485, 89478485, 0, 87652393, 87652393, 0, 85899345, 85899345, 0, 84215045, 84215045, 0, 82595524, 82595524, 0, 81037118, 81037118, 0, 79536431, 79536431, 0, 78090314, 78090314, 0, 76695844, 76695844, 0, 75350303, 75350303, 0, 74051160, 74051160, 0, 72796055, 72796055, 0, 71582788, 71582788, 0, 70409299, 70409299, 0, 69273666, 69273666, 0, 68174084, 68174084, 0, -2147483648, 0, 5]
 
-# for i in weirdArray:
-#    print('%02x'%i)
+# Minecraft stores block and heightmap data in compacted arrays of longs. This class does the proper index mapping and bit shifting to get to the actual data.
 
-'''
-This class was ported from the Minecraft source. Minecraft stores block and heightmap data in compacted arrays of longs. This class does the proper index mapping and bit shifting to get to the actual data.
-'''
 class BitArray:
    def __init__(self, bitsPerEntryIn, arraySizeIn, data):
       inclusiveBetween(1, 32, bitsPerEntryIn)
       self.arraySize = arraySizeIn
       self.bitsPerEntry = bitsPerEntryIn
       self.maxEntryValue = (1 << bitsPerEntryIn) - 1
       self.entriesPerLong = floor(64 / bitsPerEntryIn)
-      i = 3 * (self.entriesPerLong - 1)
-      self.someKindaInterval = weirdArray[i + 0]
-      self.lengthyBits = weirdArray[i + 1]
-      self.lengthyBitOffset = weirdArray[i + 2]
       j = floor((arraySizeIn + self.entriesPerLong - 1) / self.entriesPerLong)
       if (data != None):
          if (len(data) != j):
             raise Exception("Invalid length given for storage, got: %s but expected: %s" % (len(data), j))
 
          self.longArray = data
       else:
-         self.longArray = [] #new long[j]
-
-
-
-
-   # def getPosOfLong(self, index):
-   #  #   i = Integer.toUnsignedong(self.field_232983_g_)
-   #    i = self.someKindaInterval % (1<<64)
-   #  #   j = Integer.toUnsignedong(self.field_232984_h_)
-   #    j = self.lengthyBits % (1<<64)
-   #    return (index * i + j >> 32 >> self.lengthyBitOffset) % (1<<32)
+         self.longArray = [] # length j
 
 
    def getPosOfLong(self, index):
       return int(index / self.entriesPerLong)
-      # i = self.someKindaInterval % (1<<64)
-      # j = self.lengthyBits % (1<<64)
-      # return (int)(((index * i) % (1<<64) + j) % (1<<64) >> 32 >> self.lengthyBitOffset);
-
-   def swapAt(self, index, value):
-      inclusiveBetween(0, (self.arraySize - 1), index)
-      inclusiveBetween(0, self.maxEntryValue, value)
-      i = self.getPosOfLong(index)
-      j = self.longArray[i]
-      k = (index - i * self.entriesPerLong) * self.bitsPerEntry
-      l = (j >> k & self.maxEntryValue)
-      self.longArray[i] = j & ~(self.maxEntryValue << k) | (value & self.maxEntryValue) << k
-      return l
-
-
-   '''
-    * Sets the entry at the given location to the given value
-   '''
-   def setAt(self, index, value):
-      inclusiveBetween(0, (self.arraySize - 1), index)
-      inclusiveBetween(0, self.maxEntryValue, value)
-      i = self.getPosOfLong(index)
-      j = self.longArray[i]
-      k = (index - i * self.entriesPerLong) * self.bitsPerEntry
-      self.longArray[i] = j & ~(self.maxEntryValue << k) | (value & self.maxEntryValue) << k
-
 
-   '''
-    * Gets the entry at the given index
-   '''
    def getAt(self, index):
       inclusiveBetween(0, (self.arraySize - 1), index)
       i = self.getPosOfLong(index)
@@ -89,24 +38,6 @@ def getAt(self, index):
       return (j >> k & self.maxEntryValue)
 
 
-   '''
-    * Gets the array that is used to store the data in this BitArray. This is useful for sending packet data.
-   '''
-   def getBackingongArray(self):
-      return self.longArray
-
-
    def size(self):
       return self.arraySize
-
-
-   def getAll(self, consumer):
-      i = 0
-
-      for j in self.longArray:
-         for k in range(self.entriesPerLong):
-            consumer(j & self.maxEntryValue)
-            j >>= self.bitsPerEntry
-            i += 1
-            if (i >= self.arraySize):
-               return
+