From 5810eeb4aed0a1e1e1bc1e114a6916c8ec9e109b Mon Sep 17 00:00:00 2001
From: kalmarek <kalmar@amu.edu.pl>
Date: Tue, 24 Mar 2020 23:44:03 +0100
Subject: [PATCH] create uniform hash interface using hash_internal

---
 src/AutGroup.jl  | 19 +++++++++----------
 src/FPGroups.jl  |  2 --
 src/FreeGroup.jl |  2 --
 src/Groups.jl    | 10 +++++++++-
 4 files changed, 18 insertions(+), 15 deletions(-)

diff --git a/src/AutGroup.jl b/src/AutGroup.jl
index 7695278..09ed682 100644
--- a/src/AutGroup.jl
+++ b/src/AutGroup.jl
@@ -242,19 +242,18 @@ evaluate(f::Automorphism) = f(domain(parent(f)))
 
 const HASHINGCONST = 0x7d28276b01874b19 # hash(Automorphism)
 
-hash(s::AutSymbol, h::UInt) = hash(s.id, hash(s.pow, hash(:AutSymbol, h)))
+hash(s::AutSymbol, h::UInt) = hash(s.id, hash(s.pow, hash(AutSymbol, h)))
 
-function hash(g::Automorphism{N}, images, h::UInt=HASHINGCONST) where N
-    return hash(images, hash(parent(g), hash(Automorphism{N}, h)))
+function hash_internal(g::Automorphism, images = freereduce!.(evaluate(g)),
+    h::UInt = HASHINGCONST)
+    return hash(images, hash(parent(g), h))
 end
 
-function hash(g::Automorphism, h::UInt)
-    if g.modified
-        g_im = reduce!.(evaluate(g))
-        g.savedhash = hash(g, g_im)
-        g.modified = false
-    end
-    return xor(g.savedhash, h)
+function compute_images(g::Automorphism)
+    images = reduce!.(evaluate(g))
+    g.savedhash = hash_internal(g, images)
+    unsetmodified!(g)
+    return images
 end
 
 function (==)(g::Automorphism{N}, h::Automorphism{N}) where N
diff --git a/src/FPGroups.jl b/src/FPGroups.jl
index e7aeb84..ef5b036 100644
--- a/src/FPGroups.jl
+++ b/src/FPGroups.jl
@@ -95,8 +95,6 @@ end
 #
 ###############################################################################
 
-hash(s::FPSymbol, h::UInt) = hash(s.id, hash(s.pow, hash(FPSymbol, h)))
-
 change_pow(s::FPSymbol, n::Int) = FPSymbol(s.id, n)
 
 length(s::FPSymbol) = abs(s.pow)
diff --git a/src/FreeGroup.jl b/src/FreeGroup.jl
index 9e3709e..5f77479 100644
--- a/src/FreeGroup.jl
+++ b/src/FreeGroup.jl
@@ -80,8 +80,6 @@ end
 #
 ###############################################################################
 
-hash(s::FreeSymbol, h::UInt) = hash(s.id, hash(s.pow, hash(FreeSymbol, h)))
-
 change_pow(s::FreeSymbol, n::Int) = FreeSymbol(s.id, n)
 
 length(s::FreeSymbol) = abs(s.pow)
diff --git a/src/Groups.jl b/src/Groups.jl
index ee021e8..64d4e25 100644
--- a/src/Groups.jl
+++ b/src/Groups.jl
@@ -101,8 +101,16 @@ convert(::Type{GroupWord{T}}, s::T) where {T<:GSymbol} = GroupWord{T}(T[s])
 #
 ###############################################################################
 
+function hash_internal(W::GWord)
+    reduce!(W)
+    return hash(syllables(W), hash(typeof(W), hash(parent(W))))
+end
+
 function hash(W::GWord, h::UInt)
-    W.modified && reduce!(W)
+    if ismodified(W)
+        W.savedhash = hash_internal(W)
+        unsetmodified!(W)
+    end
     return xor(W.savedhash, h)
 end