merge similar procs regarding digits (#18318)

lib/system/strmantle.nim

@@ -9,72 +9,9 @@
 
 # Compilerprocs for strings that do not depend on the string implementation.
 
-const digitsTable = "0001020304050607080910111213141516171819" &
-    "2021222324252627282930313233343536373839" &
-    "4041424344454647484950515253545556575859" &
-    "6061626364656667686970717273747576777879" &
-    "8081828384858687888990919293949596979899"
-  # Inspired by https://engineering.fb.com/2013/03/15/developer-tools/three-optimization-tips-for-c
-  # Generates:
-  # .. code-block:: nim
-  #   var res = ""
-  #   for i in 0 .. 99:
-  #     if i < 10:
-  #       res.add "0" & $i
-  #     else:
-  #       res.add $i
-  #   doAssert res == digitsTable
+import std/private/digitsutils
 
 
-func digits10(num: uint64): int {.noinline.} =
-  if num < 10'u64:
-    result = 1
-  elif num < 100'u64:
-    result = 2
-  elif num < 1_000'u64:
-    result = 3
-  elif num < 10_000'u64:
-    result = 4
-  elif num < 100_000'u64:
-    result = 5
-  elif num < 1_000_000'u64:
-    result = 6
-  elif num < 10_000_000'u64:
-    result = 7
-  elif num < 100_000_000'u64:
-    result = 8
-  elif num < 1_000_000_000'u64:
-    result = 9
-  elif num < 10_000_000_000'u64:
-    result = 10
-  elif num < 100_000_000_000'u64:
-    result = 11
-  elif num < 1_000_000_000_000'u64:
-    result = 12
-  else:
-    result = 12 + digits10(num div 1_000_000_000_000'u64)
-
-template numToString(result: var string, origin: uint64, length: int) =
-  var num = origin
-  var next = length - 1
-  const nbatch = 100
-
-  while num >= nbatch:
-    let originNum = num
-    num = num div nbatch
-    let index = (originNum - num * nbatch) shl 1
-    result[next] = digitsTable[index + 1]
-    result[next - 1] = digitsTable[index]
-    dec(next, 2)
-
-  # process last 1-2 digits
-  if num < 10:
-    result[next] = chr(ord('0') + num)
-  else:
-    let index = num * 2
-    result[next] = digitsTable[index + 1]
-    result[next - 1] = digitsTable[index]
-
 proc cmpStrings(a, b: string): int {.inline, compilerproc.} =
   let alen = a.len
   let blen = b.len