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proof-pile / formal /afp /BDD /ShareRepProof.thy
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(* Title: BDD
Author: Veronika Ortner and Norbert Schirmer, 2004
Maintainer: Norbert Schirmer, norbert.schirmer at web de
License: LGPL
*)
(*
ShareRepProof.thy
Copyright (C) 2004-2008 Veronika Ortner and Norbert Schirmer
Some rights reserved, TU Muenchen
This library is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation; either version 2.1 of the
License, or (at your option) any later version.
This library is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
USA
*)
section \<open>Proof of Procedure ShareRep\<close>
theory ShareRepProof imports ProcedureSpecs Simpl.HeapList begin
lemma (in ShareRep_impl) ShareRep_modifies:
shows "\<forall>\<sigma>. \<Gamma>\<turnstile>{\<sigma>} PROC ShareRep (\<acute>nodeslist, \<acute>p)
{t. t may_only_modify_globals \<sigma> in [rep]}"
apply (hoare_rule HoarePartial.ProcRec1)
apply (vcg spec=modifies)
done
lemma hd_filter_cons:
"\<And> i. \<lbrakk> P (xs ! i) p; i < length xs; \<forall> no \<in> set (take i xs). \<not> P no p; \<forall> a b. P a b = P b a\<rbrakk>
\<Longrightarrow> xs ! i = hd (filter (P p) xs)"
apply (induct xs)
apply simp
apply (case_tac "P a p")
apply simp
apply (case_tac i)
apply simp
apply simp
apply (case_tac i)
apply simp
apply auto
done
lemma (in ShareRep_impl) ShareRep_spec_total:
shows
"\<forall>\<sigma> ns. \<Gamma>,\<Theta>\<turnstile>\<^sub>t
\<lbrace>\<sigma>. List \<acute>nodeslist \<acute>next ns \<and>
(\<forall>no \<in> set ns. no \<noteq> Null \<and>
((no\<rightarrow>\<acute>low = Null) = (no\<rightarrow>\<acute>high = Null)) \<and>
(isLeaf_pt \<acute>p \<acute>low \<acute>high \<longrightarrow> isLeaf_pt no \<acute>low \<acute>high) \<and>
no\<rightarrow>\<acute>var = \<acute>p\<rightarrow>\<acute>var) \<and>
\<acute>p \<in> set ns\<rbrace>
PROC ShareRep (\<acute>nodeslist, \<acute>p)
\<lbrace> (\<^bsup>\<sigma>\<^esup>p \<rightarrow> \<acute>rep = hd (filter (\<lambda> sn. repNodes_eq sn \<^bsup>\<sigma>\<^esup>p \<^bsup>\<sigma>\<^esup>low \<^bsup>\<sigma>\<^esup>high \<^bsup>\<sigma>\<^esup>rep) ns)) \<and>
(\<forall>pt. pt \<noteq> \<^bsup>\<sigma>\<^esup>p \<longrightarrow> pt\<rightarrow>\<^bsup>\<sigma>\<^esup>rep = pt\<rightarrow>\<acute>rep) \<and>
(\<^bsup>\<sigma>\<^esup>p\<rightarrow>\<acute>rep\<rightarrow>\<^bsup>\<sigma>\<^esup>var = \<^bsup>\<sigma>\<^esup>p \<rightarrow> \<^bsup>\<sigma>\<^esup>var)\<rbrace>"
apply (hoare_rule HoareTotal.ProcNoRec1)
apply (hoare_rule anno=
"IF (isLeaf_pt \<acute>p \<acute>low \<acute>high)
THEN \<acute>p \<rightarrow> \<acute>rep :== \<acute>nodeslist
ELSE
WHILE (\<acute>nodeslist \<noteq> Null)
INV \<lbrace>\<exists>prx sfx. List \<acute>nodeslist \<acute>next sfx \<and> ns=prx@sfx \<and>
\<not> isLeaf_pt \<acute>p \<acute>low \<acute>high \<and>
(\<forall>no \<in> set ns. no \<noteq> Null \<and>
((no\<rightarrow>\<^bsup>\<sigma>\<^esup>low = Null) = (no\<rightarrow>\<^bsup>\<sigma>\<^esup>high = Null)) \<and>
(isLeaf_pt \<^bsup>\<sigma>\<^esup>p \<^bsup>\<sigma>\<^esup>low \<^bsup>\<sigma>\<^esup>high \<longrightarrow> isLeaf_pt no \<^bsup>\<sigma>\<^esup>low \<^bsup>\<sigma>\<^esup>high) \<and>
no\<rightarrow>\<^bsup>\<sigma>\<^esup>var = \<^bsup>\<sigma>\<^esup>p\<rightarrow>\<^bsup>\<sigma>\<^esup>var) \<and>
\<^bsup>\<sigma>\<^esup>p \<in> set ns \<and>
((\<exists>pt \<in> set prx. repNodes_eq pt \<^bsup>\<sigma>\<^esup>p \<^bsup>\<sigma>\<^esup>low \<^bsup>\<sigma>\<^esup>high \<^bsup>\<sigma>\<^esup>rep)
\<longrightarrow> \<acute>rep \<^bsup>\<sigma>\<^esup>p = hd (filter (\<lambda> sn. repNodes_eq sn \<^bsup>\<sigma>\<^esup>p \<^bsup>\<sigma>\<^esup>low \<^bsup>\<sigma>\<^esup>high \<^bsup>\<sigma>\<^esup>rep) prx) \<and>
(\<forall>pt. pt \<noteq> \<^bsup>\<sigma>\<^esup>p \<longrightarrow> pt\<rightarrow>\<^bsup>\<sigma>\<^esup>rep = pt\<rightarrow>\<acute>rep)) \<and>
((\<forall>pt \<in> set prx. \<not> repNodes_eq pt \<^bsup>\<sigma>\<^esup>p \<^bsup>\<sigma>\<^esup>low \<^bsup>\<sigma>\<^esup>high \<^bsup>\<sigma>\<^esup>rep) \<longrightarrow> \<^bsup>\<sigma>\<^esup>rep = \<acute>rep) \<and>
(\<acute>nodeslist \<noteq> Null \<longrightarrow>
(\<forall>pt \<in> set prx. \<not> repNodes_eq pt \<^bsup>\<sigma>\<^esup>p \<^bsup>\<sigma>\<^esup>low \<^bsup>\<sigma>\<^esup>high \<^bsup>\<sigma>\<^esup>rep)) \<and>
(\<acute>p = \<^bsup>\<sigma>\<^esup>p \<and> \<acute>high = \<^bsup>\<sigma>\<^esup>high \<and> \<acute>low = \<^bsup>\<sigma>\<^esup>low)\<rbrace>
VAR MEASURE (length (list \<acute>nodeslist \<acute>next))
DO
IF (repNodes_eq \<acute>nodeslist \<acute>p \<acute>low \<acute>high \<acute>rep)
THEN \<acute>p\<rightarrow>\<acute>rep :== \<acute>nodeslist;; \<acute>nodeslist :== Null
ELSE \<acute>nodeslist :== \<acute>nodeslist\<rightarrow>\<acute>next
FI
OD
FI" in HoareTotal.annotateI)
apply vcg
using [[simp_depth_limit = 2]]
apply (rule conjI)
apply clarify
apply (simp (no_asm_use))
prefer 2
apply clarify
apply (rule_tac x="[]" in exI)
apply (rule_tac x=ns in exI)
apply (simp (no_asm_use))
prefer 2
apply clarify
apply (rule conjI)
apply clarify
apply (rule conjI)
apply (clarsimp simp add: List_list) (* solving termination contraint *)
apply (simp (no_asm_use))
apply (rule conjI)
apply assumption
prefer 2
apply clarify
apply (simp (no_asm_use))
apply (rule conjI)
apply (clarsimp simp add: List_list) (* solving termination constraint *)
apply (simp only: List_not_Null simp_thms triv_forall_equality)
apply clarify
apply (simp only: triv_forall_equality)
apply (rename_tac sfx)
apply (rule_tac x="prx@[nodeslist]" in exI)
apply (rule_tac x="sfx" in exI)
apply (rule conjI)
apply assumption
apply (rule conjI)
apply simp
prefer 4
apply (elim exE conjE)
apply (simp (no_asm_use))
apply hypsubst
using [[simp_depth_limit = 100]]
proof -
(* IF-THEN to postcondition *)
fix ns var low high rep "next" p nodeslist
assume ns: "List nodeslist next ns"
assume no_prop: "\<forall>no\<in>set ns.
no \<noteq> Null \<and>
(low no = Null) = (high no = Null) \<and>
(isLeaf_pt p low high \<longrightarrow> isLeaf_pt no low high) \<and> var no = var p"
assume p_in_ns: "p \<in> set ns"
assume p_Leaf: "isLeaf_pt p low high"
show "nodeslist = hd [sn\<leftarrow>ns . repNodes_eq sn p low high rep] \<and>
var nodeslist = var p"
proof -
from p_in_ns no_prop have p_not_Null: "p\<noteq>Null"
using [[simp_depth_limit=2]]
by auto
from p_in_ns have "ns \<noteq> []"
by (cases ns) auto
with ns obtain ns' where ns': "ns = nodeslist#ns'"
by (cases "nodeslist=Null") auto
with no_prop p_Leaf obtain
"isLeaf_pt nodeslist low high" and
var_eq: "var nodeslist = var p" and
"nodeslist\<noteq>Null"
using [[simp_depth_limit=2]]
by auto
with p_not_Null p_Leaf have "repNodes_eq nodeslist p low high rep"
by (simp add: repNodes_eq_def isLeaf_pt_def null_comp_def)
with ns' var_eq
show ?thesis
by simp
qed
next
(* From invariant to postcondition *)
fix var::"ref\<Rightarrow>nat" and low high rep repa p prx sfx "next"
assume sfx: "List Null next sfx"
assume p_in_ns: "p \<in> set (prx @ sfx)"
assume no_props: "\<forall>no\<in>set (prx @ sfx).
no \<noteq> Null \<and>
(low no = Null) = (high no = Null) \<and>
(isLeaf_pt p low high \<longrightarrow> isLeaf_pt no low high) \<and> var no = var p"
assume match_prx: "(\<exists>pt\<in>set prx. repNodes_eq pt p low high rep) \<longrightarrow>
repa p = hd [sn\<leftarrow>prx . repNodes_eq sn p low high rep] \<and>
(\<forall>pt. pt \<noteq> p \<longrightarrow> rep pt = repa pt)"
show "repa p = hd [sn\<leftarrow>prx @ sfx . repNodes_eq sn p low high rep] \<and>
(\<forall>pt. pt \<noteq> p \<longrightarrow> rep pt = repa pt) \<and> var (repa p) = var p"
proof -
from sfx
have sfx_Nil: "sfx=[]"
by simp
with p_in_ns have ex_match: "(\<exists>pt\<in>set prx. repNodes_eq pt p low high rep)"
apply -
apply (rule_tac x=p in bexI)
apply (simp add: repNodes_eq_def)
apply simp
done
hence not_empty: "[sn\<leftarrow>prx . repNodes_eq sn p low high rep] \<noteq> []"
apply -
apply (erule bexE)
apply (rule filter_not_empty)
apply auto
done
from ex_match match_prx obtain
found: "repa p = hd [sn\<leftarrow>prx . repNodes_eq sn p low high rep]" and
unmodif: "\<forall>pt. pt \<noteq> p \<longrightarrow> rep pt = repa pt"
by blast
from hd_filter_in_list [OF not_empty] found
have "repa p \<in> set prx"
by simp
with no_props
have "var (repa p) = var p"
using [[simp_depth_limit=2]]
by simp
with found unmodif sfx_Nil
show ?thesis
by simp
qed
next
(* Invariant to invariant; ELSE part *)
fix var low high p repa "next" nodeslist prx sfx
assume nodeslist_not_Null: "nodeslist \<noteq> Null"
assume p_no_Leaf: "\<not> isLeaf_pt p low high"
assume no_props: "\<forall>no\<in>set prx \<union> set (nodeslist # sfx).
no \<noteq> Null \<and> (low no = Null) = (high no = Null) \<and> var no = var p"
assume p_in_ns: "p \<in> set prx \<or> p \<in> set (nodeslist # sfx)"
assume match_prx: "(\<exists>pt\<in>set prx. repNodes_eq pt p low high repa) \<longrightarrow>
repa p = hd [sn\<leftarrow>prx . repNodes_eq sn p low high repa]"
assume nomatch_prx: "\<forall>pt\<in>set prx. \<not> repNodes_eq pt p low high repa"
assume nomatch_nodeslist: "\<not> repNodes_eq nodeslist p low high repa"
assume sfx: "List (next nodeslist) next sfx"
show "(\<forall>no\<in>set prx \<union> set (nodeslist # sfx).
no \<noteq> Null \<and> (low no = Null) = (high no = Null) \<and> var no = var p) \<and>
((\<exists>pt\<in>set (prx @ [nodeslist]). repNodes_eq pt p low high repa) \<longrightarrow>
repa p = hd [sn\<leftarrow>prx @ [nodeslist] . repNodes_eq sn p low high repa]) \<and>
(next nodeslist \<noteq> Null \<longrightarrow>
(\<forall>pt\<in>set (prx @ [nodeslist]). \<not> repNodes_eq pt p low high repa))"
proof -
from nomatch_prx nomatch_nodeslist
have "((\<exists>pt\<in>set (prx @ [nodeslist]). repNodes_eq pt p low high repa) \<longrightarrow>
repa p = hd [sn\<leftarrow>prx @ [nodeslist] . repNodes_eq sn p low high repa])"
by auto
moreover
from nomatch_prx nomatch_nodeslist
have "(next nodeslist \<noteq> Null \<longrightarrow>
(\<forall>pt\<in>set (prx @ [nodeslist]). \<not> repNodes_eq pt p low high repa))"
by auto
ultimately show ?thesis
using no_props
by (intro conjI)
qed
next
(* Invariant to invariant: THEN part *)
fix var low high p repa "next" nodeslist prx sfx
assume nodeslist_not_Null: "nodeslist \<noteq> Null"
assume sfx: "List nodeslist next sfx"
assume p_not_Leaf: "\<not> isLeaf_pt p low high"
assume no_props: "\<forall>no\<in>set prx \<union> set sfx.
no \<noteq> Null \<and>
(low no = Null) = (high no = Null) \<and>
(isLeaf_pt p low high \<longrightarrow> isLeaf_pt no low high) \<and> var no = var p"
assume p_in_ns: "p \<in> set prx \<or> p \<in> set sfx"
assume match_prx: "(\<exists>pt\<in>set prx. repNodes_eq pt p low high repa) \<longrightarrow>
repa p = hd [sn\<leftarrow>prx . repNodes_eq sn p low high repa]"
assume nomatch_prx: "\<forall>pt\<in>set prx. \<not> repNodes_eq pt p low high repa"
assume match: "repNodes_eq nodeslist p low high repa"
show "(\<forall>no\<in>set prx \<union> set sfx.
no \<noteq> Null \<and>
(low no = Null) = (high no = Null) \<and>
(isLeaf_pt p low high \<longrightarrow> isLeaf_pt no low high) \<and> var no = var p) \<and>
(p \<in> set prx \<or> p \<in> set sfx) \<and>
((\<exists>pt\<in>set prx \<union> set sfx. repNodes_eq pt p low high repa) \<longrightarrow>
nodeslist =
hd ([sn\<leftarrow>prx . repNodes_eq sn p low high repa] @
[sn\<leftarrow>sfx . repNodes_eq sn p low high repa])) \<and>
((\<forall>pt\<in>set prx \<union> set sfx. \<not> repNodes_eq pt p low high repa) \<longrightarrow>
repa = repa(p := nodeslist))"
proof -
from nodeslist_not_Null sfx
obtain sfx' where sfx': "sfx=nodeslist#sfx'"
by (cases "nodeslist=Null") auto
from nomatch_prx match sfx'
have hd: "hd ([sn\<leftarrow>prx . repNodes_eq sn p low high repa] @
[sn\<leftarrow>sfx . repNodes_eq sn p low high repa]) = nodeslist"
by simp
from match sfx'
have triv: "((\<forall>pt\<in>set prx \<union> set sfx. \<not> repNodes_eq pt p low high repa) \<longrightarrow>
repa = repa(p := nodeslist))"
by simp
show ?thesis
apply (rule conjI)
apply (rule no_props)
apply (intro conjI)
apply (rule p_in_ns)
apply (simp add: hd)
apply (rule triv)
done
qed
qed
end