From 049952886b21cd2911cb3e62f895c90a9c6cd376 Mon Sep 17 00:00:00 2001
From: Stefan Karpinski <stefan@karpinski.org>
Date: Sat, 15 Sep 2018 14:10:11 -0400
Subject: [PATCH] =?UTF-8?q?fix=20digits(n::Unsigned)=20with=20neg=20base?=
 =?UTF-8?q?=20for=20`n=20>=20typemax(n)=C3=B72`?=
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Alternative based on https://github.com/JuliaLang/julia/pull/29187
---
 base/intfuncs.jl | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/base/intfuncs.jl b/base/intfuncs.jl
index a6f6ea05efe41d..8b9f3d441ec012 100644
--- a/base/intfuncs.jl
+++ b/base/intfuncs.jl
@@ -744,17 +744,25 @@ julia> digits!([2,2,2,2,2,2], 10, base = 2)
 ```
 """
 function digits!(a::AbstractVector{T}, n::Integer; base::Integer = 10) where T<:Integer
-    base < 0 && isa(n, Unsigned) && return digits!(a, convert(Signed, n), base = base)
     2 <= abs(base) || throw(ArgumentError("base must be ≥ 2 or ≤ -2, got $base"))
     hastypemax(T) && abs(base) - 1 > typemax(T) &&
         throw(ArgumentError("type $T too small for base $base"))
-    for i in eachindex(a)
-        if base > 0
-            a[i] = rem(n, base)
-            n = div(n, base)
-        else
-            a[i] = mod(n, -base)
-            n = cld(n, base)
+    isempty(a) && return a
+
+    if base > 0
+        for i in eachindex(a)
+            n, d = divrem(n, base)
+            a[i] = d
+        end
+    else
+        # manually peel one loop iteration for type stability
+        n, d = fldmod(n, -base)
+        a[firstindex(a)] = d
+        n = -signed(n)
+        for i in firstindex(a)+1:lastindex(a)
+            n, d = fldmod(n, -base)
+            a[i] = d
+            n = -n
         end
     end
     return a