fix mask selection

combinators.nim

@@ -1,5 +1,5 @@
 import algorithm, random, sugar
-import fastrand, fixedseq, game
+import faststack, fixedseq, game
 
 
 proc nextPermutation(x: var FixedSeq): bool =
@@ -93,4 +93,4 @@ proc randomFuture*(dice: FixedSeq, r: var Rand): FixedSeq[5, Die, int8] =
   result.initFixedSeq
   let order = dice.dup(shuffle(r))
   for i, color in order:
-    result.add((color, r.fastRand(1..3)))
+    result.add((color, r.rand(1..3)))

config.nims

@@ -1,5 +1,5 @@
---threads: on
---d: release
---opt: speed
---passC: -flto
---passL: -flto
+# --threads: on
+# --d: release
+# --opt: speed
+# --passC: -flto
+# --passL: -flto

fastrand.nim

@@ -1,74 +0,0 @@
-import random, math
-import times, std/monotimes, strformat, strutils
-
-
-proc formatNum(n: SomeNumber): string =
-  let s = $(n.round)
-  let t = s[0 .. s.len - 3]
-  var count = 1
-  for i in countdown(t.high, 0):
-    result.insert($t[i], 0)
-    if count mod 3 == 0 and i != 0:
-      result.insert(",", 0)
-    count += 1
-
-
-proc formatRate(n: Natural, d: Duration): string =
-  result = formatNum(1_000_000'f64 * n.float64 / d.inMicroseconds.float64)
-
-
-const upperBound = uint64(uint32.high)
-
-
-proc fastRand*[T: Natural](r: var Rand, x: T): T =
-  # Nim ranges are usually inclusive, but this algorithm is exclusive
-  let x = x.uint64 + 1
-  let num = if x <= upperBound:
-    ((r.next shr 32) * x.uint64) shr 32
-  else:
-    r.next mod x.uint64
-  result = T(num)
-
-
-proc fastRand*(r: var Rand; x, y: Natural): Natural =
-  let lim = (y - x)
-  result = fastRand(r, lim) + x
-
-
-proc fastRand*[T](r: var Rand, slice: HSlice[T, T]): T =
-  let n = fastRand(r, slice.a.Natural, slice.b.Natural)
-  result = T(n)
-
-
-proc testFastRand(num = 1_000_000_000): Duration =
-  var r = initRand(rand(int64))
-  let start = getMonoTime()
-  for i in 1 .. num:
-    discard r.fastRand(5)
-  result = getMonoTime() - start
-  # echo "fastrand execution rate: ",  1000 * num / dur.inMilliseconds.int, " generated per second."
-
-
-proc testStdRand(num = 1_000_000_000): Duration =
-  var r = initRand(rand(int64))
-  let start = getMonoTime()
-  for i in 1 .. num:
-    discard r.rand(4)
-  result = getMonoTime() - start
-  # echo "std rand execution rate: ", 1000 * num / dur.inMilliseconds.int, " generated per second."
-
-
-when isMainModule:
-  randomize()
-  var r = initRand(rand(int64))
-  let runs = 100_000_000
-  var totals: array[5..9, int]
-  for i in 1 .. runs:
-    let n = r.fastRand(5..9)
-    totals[n] += 1
-  echo totals
-
-  # let fr = testFastRand(runs)
-  # echo "fastrand execution rate: ", formatNum(1_000_000 * runs / fr.inMicroseconds.int)
-  # let sr = testStdRand(runs)
-  # echo "standard execution rate: ", formatNum(1_000_000 * runs / sr.inMicroseconds.int)

faststack.nim

@@ -0,0 +1,204 @@
+import bitops, strutils, random
+
+
+proc show(i: SomeInteger, bitlength = 16) =
+  echo BiggestInt(i).toBin(bitlength)
+
+
+type
+  Color* = enum
+    cRed, cGreen, cBlue, cYellow, cPurple
+
+  ColorStack* = object
+    data: uint16
+    len*: uint8
+
+
+const
+  masks = [
+    0'u16, # dummy value just to get the indices right
+    0b0_000_000_000_000_111,
+    0b0_000_000_000_111_111,
+    0b0_000_000_111_111_111,
+    0b0_000_111_111_111_111,
+    0b0_111_111_111_111_111,
+  ]
+  allColors* = ColorStack(len: 5, data: 0b0_000_001_010_011_100)
+
+
+template offset(s: ColorStack, idx: Natural): uint8 =
+  # Compute the bit offset for a given index. 
+  # Dependent on the stack's length.
+  (s.len - 1 - idx.uint8) * 3
+  # items are stored from left to right but right-aligned, so we
+  # need to shift right to access anything other than the last
+
+
+template offset(s: ColorStack, idx: BackwardsIndex): uint8 =
+  # for backwards index, we are still shifting right but
+  # the lower the index the less we have to shift
+  (idx.uint8 - 1) * 3
+
+
+proc add*(s: var ColorStack, c: Color) =
+  # e.g. if stack is 0b0000000000000100:
+  # and color is 0b00000011
+  # shift: 0b0000000000100000
+  # bitor: 0b0000000000100000 and 0b00000011
+  # results in 0b0000000000100011
+  s.data = (s.data shl 3).bitor(cast[uint8](c))
+  inc s.len
+
+
+proc high*(s: ColorStack): uint8 = s.len - 1
+
+proc low*(s: ColorStack): uint8 = 0 # just... always 0, I guess
+
+
+proc `[]`*(s: ColorStack, i: uint8 | BackwardsIndex): Color =
+  # shift, then mask everything but the three rightmost bits
+  result = Color(
+    (s.data shr s.offset(i)) and masks[1]
+  )
+
+
+proc `[]=`*(s: var ColorStack, i: uint8 | BackwardsIndex, c: Color) =
+  let offset = s.offset(i)
+  s.data = (s.data and bitnot(masks[1] shl offset)) or (c.uint16 shl offset)
+
+
+iterator items*(s: ColorStack): Color =
+  # s.len is unsigned so it will wrap around if we do s.len - 1 in that case
+  if s.len != 0:
+    for i in countdown(s.len - 1, 0'u8):
+      yield Color((s.data shr (i * 3)) and masks[1])
+
+
+iterator pairs*(s: ColorStack): (uint8, Color) =
+  var count = 0'u8
+  for color in s:
+    yield (count, color)
+    inc count
+
+
+proc find*(s: ColorStack, needle: Color): int8 =
+  for i in 0'u8 .. s.high:
+    if s[i] == needle:
+      return i.int8
+  return -1
+
+
+proc moveSubstack*(src, dst: var ColorStack, startIdx: uint8) =
+  if startIdx >= src.len:
+    raise newException(IndexDefect, "index " & $startIdx & " is out of bounds.")
+  # Moves a sub-stack from the top of src to the top of dst
+  # shift the dst stack by the length of the substack to make room
+  let nToMove = src.len - startIdx
+  let shift = nToMove * 3
+  dst.data = dst.data shl shift
+  # then we mask the source data to present only the items 
+  # being moved, and OR that with the shifted dst data
+  dst.data = dst.data or (src.data and masks[nToMove])
+  dst.len += nToMove
+  # then we shift the source to get rid of the moved items
+  src.data = src.data shr shift
+  src.len -= nToMove
+
+
+proc moveSubstackPre*(src, dst: var ColorStack, startIdx: uint8) =
+  if startIdx >= src.len:
+    raise newException(IndexDefect, "index " & $startIdx & " is out of bounds.")
+  # Moves a sub-stack from the top of src to the bottom of dst
+  let nToMove = src.len - startIdx
+  # shift src to position the substack above its destination,
+  # get rid of everything to the left of the substack,
+  # and OR that with the existing dst data
+  let newLen = dst.len + nToMove
+  dst.data = dst.data or ( (src.data shl (dst.len * 3)) and masks[newLen] )
+  dst.len = newLen
+  # get rid of the substack we just moved
+  src.data = src.data shr (nToMove * 3)
+  src.len -= nToMove
+
+
+proc swap*(s: var ColorStack, i1, i2: uint8) =
+  # Swap the values at two indices in the stack
+  if i1 == i2: return
+
+  # i1 and i2 are unsigned, so we have to watch out for underflows
+  let diff = if i1 > i2:
+    (i1 - i2) * 3
+  else:
+    (i2 - i1) * 3
+
+  # take masks[1] from above (rightmost position) and shift to position of i1.
+  # then do the same for i2, and OR them together.
+  let mask = (masks[1] shl s.offset(i1)) or (masks[1] shl s.offset(i2))
+  # get rid of everything but the two values we're swapping
+  let masked = s.data and mask
+  # shift by the distance between values in both directions, combine, then mask
+  let swapped = ((masked shl diff) or (masked shr diff)) and mask
+  # finally, AND with the inverse of mask so that only the values being 
+  # swapped are erased, and combine that with the swapped values
+  s.data = (s.data and mask.bitnot) or swapped
+
+
+proc shuffle*(r: var Rand, s: var ColorStack) =
+  # Fisher-Yates shuffle
+  for i in countdown(s.high, 1'u8):
+    let j = r.rand(i).uint8
+    if j != i:
+      s.swap(i, j)
+
+
+proc reverse*(s: var ColorStack, first, last: uint8) =
+  var x = first
+  var y = last
+  while x < y:
+    s.swap(x, y)
+    inc x
+    dec y
+
+
+iterator asInt*(s: ColorStack): int8 =
+  for i in 0'u8 .. s.high:
+    yield int8(s[i]) # now we do have to convert
+
+
+proc `$`*(s: ColorStack): string =
+  result = "St@["
+  for c in s:
+    if result[^1] != '[':
+      result.add(", ")
+    result.add($c)
+  result.add("]")
+
+
+proc check(s: ColorStack) =
+  # ensure length is accurate
+  var d = s.data
+  for i in 0'u8 .. 4'u8:
+    if (d and masks[1]) > 4:
+      raise newException(RangeDefect, "Value out of range.")
+    if d > 0 and i >= s.len:
+      raise newException(RangeDefect, "Invalid length.")
+    else:
+      d = d shr 3
+
+
+when isMainModule:
+  var one: ColorStack
+  one.add(cRed)
+  one.add(cGreen)
+  one.add(cBlue)
+  one.add(cYellow)
+  one.add(cPurple)
+
+  var two: ColorStack
+
+  one.moveSubstack(two, 2)
+
+
+  echo one, " ", one.len
+  echo two, " ", two.len
+  echo two.find(cRed)

game.nim

@@ -1,25 +1,26 @@
 import hashes, options
-import fixedseq
+import fixedseq, faststack
+
+export faststack.Color, faststack.ColorStack, faststack.allColors
 
 
-type
-  Color* = enum
-    cRed, cGreen, cBlue, cYellow, cPurple
+# type
+#   Color* = enum
+#     cRed, cGreen, cBlue, cYellow, cPurple
 
-  ColorStack* = FixedSeq[5, Color, int8]
+#   ColorStack* = FixedSeq[5, Color, int8]
 
 
-proc initColorStack*: ColorStack =
-  result.initFixedSeq
+# proc initColorStack*: ColorStack =
+#   result.initFixedSeq
 
 
-proc getAllColors: ColorStack = 
-  var i = 0
-  for c in Color.low .. Color.high:
-    result[i] = c
+# proc getAllColors: ColorStack = 
+#   var i = 0'u8
+#   for c in Color.low .. Color.high:
+#     result[i] = c
 
-const 
-  allColors* = getAllColors()
+const
   colorNames: array[Color, string] =
     ["Red", "Green", "Blue", "Yellow", "Purple"]
   colorAbbrevs: array[Color, char] = ['R', 'G', 'B', 'Y', 'P']
@@ -82,8 +83,8 @@ proc hash*(b: Board): Hash =
 
 
 proc init*(b: var Board) =
-  for sq in b.squares.mitems:
-    sq.camels.initFixedSeq
+  # for sq in b.squares.mitems:
+  #   sq.camels.initFixedSeq
   b.initialized = true
 
 
@@ -112,7 +113,7 @@ proc setState*(b: var Board;
   b.leader = some(leadCamel)
 
 
-proc diceRemaining*(b: Board): ColorStack =
+proc diceRemaining*(b: Board): FixedSeq[5, Color, int8] =
   result.initFixedSeq
   for color, isRolled in b.diceRolled:
     if not isRolled: result.add(color)
@@ -140,11 +141,11 @@ proc advance*(b: var Board, die: Die) =
     endPos += int(t)
     if t == tBackward: prepend = true
 
-  let stackStart = b[startPos].camels.find(color)
+  let stackStart = b[startPos].camels.find(color).uint8
   if prepend:
     b[startPos].camels.moveSubstackPre(b[endPos].camels, stackStart)
     let stackLen = b[startPos].camels.len - stackStart
-    for i in 0 ..< stackLen:
+    for i in 0'u8 ..< stackLen:
       # we know how many camels we added to the bottom, so set the position for each of those
       b.camels[b[endPos].camels[i]] = endPos
   else:
@@ -158,4 +159,4 @@ proc advance*(b: var Board, die: Die) =
   if endPos >= b.camels[b.leader.get]:
     b.leader = some(b[endPos].camels[^1])
   
-  b.diceRolled[color] = true
+  b.diceRolled[color] = true

simulation.nim

@@ -1,5 +1,5 @@
 import cpuinfo, math, options, random, tables
-import combinators, game, fixedseq
+import combinators, game, faststack, fixedseq
 
 
 type
@@ -38,7 +38,7 @@ proc percents*(scores: ScoreSet): WinPercents =
 # ======================
 
 iterator legEndStates(b: Board): Board =
-  var diceRemaining: ColorStack
+  var diceRemaining: FixedSeq[5, Color, int8]
   diceRemaining.initFixedSeq
   for i, c in b.diceRolled:
     if not c: diceRemaining.add(i)
@@ -59,6 +59,39 @@ proc getLegScores*(b: Board): ScoreSet =
 # Full-game simulations
 # =====================
 
+# get rid of this later
+import strutils
+proc showSpaces*(b: Board; start, stop: Natural): string =
+  let numSpaces = stop - start + 1
+  let width = 4 * numSpaces - 1
+  var lines: array[7, string]
+  # start by building up an empty board
+  for i in 0 .. 6: # gotta initialize the strings
+    lines[i] = newString(width)
+    for c in lines[i].mitems:
+      c = ' '
+  # fill in the dividers
+  lines[5] = repeat("=== ", numSpaces - 1)
+  lines[5].add("===")
+
+  # now populate the board
+  for sp in 0 ..< numSpaces:
+    # fill in the square numbers
+    let squareNum = sp + start
+    let cellMid = 4 * sp + 1
+    for i, chr in $squareNum:
+      lines[6][cellMid + i] = chr
+
+    # fill in the camel stacks
+    for i, color in b.squares[squareNum].camels:
+      let lineNum = 4 - i # lines go to 6, but bottom 2 are reserved
+      let repr = '|' & color.abbrev & '|'
+      for j, chr in repr:
+        lines[lineNum][cellMid - 1 + j] = chr
+
+  result = lines.join("\n")
+# get rid of this later
+
 proc randomGame*(b: Board, r: var Rand): Color =
   var projection = b
   while true:

ui.nim

@@ -1,5 +1,5 @@
 import os, math, strutils, strformat
-import fixedseq, game, simulation
+import faststack, fixedseq, game, simulation
 
 
 const help =