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+# Why/Jessie/Krakatoa version
+VERSION=2.21
+# Caduceus version
+CVERSION=1.21

configure.in

+##########################################################################
+#                                                                        #
+#  The Why platform for program certification                            #
+#  Copyright (C) 2002-2008                                               #
+#    Romain BARDOU                                                       #
+#    Jean-Franois COUCHOT                                               #
+#    Mehdi DOGGUY                                                        #
+#    Jean-Christophe FILLITRE                                           #
+#    Thierry HUBERT                                                      #
+#    Claude MARCH                                                       #
+#    Yannick MOY                                                         #
+#    Christine PAULIN                                                    #
+#    Yann RGIS-GIANAS                                                   #
+#    Nicolas ROUSSET                                                     #
+#    Xavier URBAIN                                                       #
+#                                                                        #
+#  This software is free software; you can redistribute it and/or        #
+#  modify it under the terms of the GNU Library General Public           #
+#  License version 2, with the special exception on linking              #
+#  described in file LICENSE.                                            #
+#                                                                        #
+#  This software 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.                  #
+#                                                                        #
+##########################################################################
+
+
+#
+# autoconf input for Objective Caml programs
+# Copyright (C) 2001 Jean-Christophe Fillitre
+#   from a first script by Georges Mariano 
+# 
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Library General Public
+# License version 2, as published by the Free Software Foundation.
+# 
+# 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 Library General Public License version 2 for more details
+# (enclosed in the file LGPL).
+
+# the script generated by autoconf from this input will set the following
+# variables:
+#   OCAMLC        "ocamlc" if present in the path, or a failure
+#                 or "ocamlc.opt" if present with same version number as ocamlc
+#   OCAMLOPT      "ocamlopt" (or "ocamlopt.opt" if present), or "no"
+#   OCAMLBEST     either "byte" if no native compiler was found, 
+#                 or "opt" otherwise
+#   OCAMLDEP      "ocamldep"
+#   OCAMLLEX      "ocamllex"
+#   OCAMLYACC     "ocamlyac"
+#   OCAMLLIB      the path to the ocaml standard library
+#   OCAMLVERSION  the ocaml version number
+#   LABLGTK2	  "yes" is available, "no" otherwise
+#   OCAMLWEB      "ocamlweb" (not mandatory)
+
+
+# check for one particular file of the sources 
+# ADAPT THE FOLLOWING LINE TO YOUR SOURCES!
+AC_INIT(src/hashcons.mli)
+
+# verbosemake feature
+
+AC_ARG_ENABLE(verbosemake,[  --enable-verbosemake    verbose makefile commands],VERBOSEMAKE=yes,VERBOSEMAKE=no)
+if test "$VERBOSEMAKE" = yes ; then
+	AC_MSG_RESULT(Make will be verbose.)
+fi
+
+
+# Check for arch/OS
+
+AC_MSG_CHECKING(executable suffix)
+if uname -s | grep -q CYGWIN ; then
+  EXE=.exe
+  STRIP='echo "no strip "'
+  CPULIMIT=cpulimit-win
+  AC_MSG_RESULT(.exe) 
+else
+  EXE=
+  STRIP=strip
+  CPULIMIT=cpulimit
+  AC_MSG_RESULT(<none>)
+fi
+
+# Check for Ocaml compilers
+
+# we first look for ocamlc in the path; if not present, we fail
+AC_CHECK_PROG(OCAMLC,ocamlc,ocamlc,no)
+if test "$OCAMLC" = no ; then
+	AC_MSG_ERROR(Cannot find ocamlc.)
+fi
+
+# we extract Ocaml version number 
+OCAMLVERSION=`$OCAMLC -v | sed -n -e 's|.*version* *\(.*\)$|\1|p' `
+echo "ocaml version is $OCAMLVERSION"
+
+case $OCAMLVERSION in
+  0.*|1.*|2.00|3.00*|3.01*|3.02*|3.03*|3.04*|3.05*|3.06*|3.07*)
+        AC_MSG_ERROR(You need Objective 3.08 or later);;
+  3.08.2)
+	FORPACK=""
+	OCAMLV=3082;;
+  3.08*)
+	FORPACK=""
+	OCAMLV=308;;
+  *)
+	FORPACK="-for-pack Graph";;
+esac
+
+# Ocaml library path
+# old way: OCAMLLIB=`$OCAMLC -v | tail -1 | cut -f 4 -d ' ' | tr -d '\\r'`
+OCAMLLIB=`$OCAMLC -where | tr -d '\\r'`
+echo "ocaml library path is $OCAMLLIB"
+
+# then we look for ocamlopt; if not present, we issue a warning
+# if the version is not the same, we also discard it
+# we set OCAMLBEST to "opt" or "byte", whether ocamlopt is available or not
+AC_CHECK_PROG(OCAMLOPT,ocamlopt,ocamlopt,no)
+OCAMLBEST=byte
+if test "$OCAMLOPT" = no ; then
+	AC_MSG_WARN(Cannot find ocamlopt; bytecode compilation only.)
+else
+	AC_MSG_CHECKING(ocamlopt version)
+	TMPVERSION=`$OCAMLOPT -v | sed -n -e 's|.*version* *\(.*\)$|\1|p' `
+	if test "$TMPVERSION" != "$OCAMLVERSION" ; then
+	    AC_MSG_RESULT(differs from ocamlc; ocamlopt discarded.)
+	    OCAMLOPT=no
+	else
+	    AC_MSG_RESULT(ok)
+	    OCAMLBEST=opt
+	fi
+fi
+
+# checking for ocamlc.opt
+AC_CHECK_PROG(OCAMLCDOTOPT,ocamlc.opt,ocamlc.opt,no)
+if test "$OCAMLCDOTOPT" != no ; then
+	AC_MSG_CHECKING(ocamlc.opt version)
+	TMPVERSION=`$OCAMLCDOTOPT -v | sed -n -e 's|.*version* *\(.*\)$|\1|p' `
+	if test "$TMPVERSION" != "$OCAMLVERSION" ; then
+	    AC_MSG_RESULT(differs from ocamlc; ocamlc.opt discarded.)
+	else
+	    AC_MSG_RESULT(ok)
+	    OCAMLC=$OCAMLCDOTOPT
+	fi
+fi
+
+# checking for ocamlopt.opt
+if test "$OCAMLOPT" != no ; then
+    AC_CHECK_PROG(OCAMLOPTDOTOPT,ocamlopt.opt,ocamlopt.opt,no)
+    if test "$OCAMLOPTDOTOPT" != no ; then
+	AC_MSG_CHECKING(ocamlc.opt version)
+	TMPVER=`$OCAMLOPTDOTOPT -v | sed -n -e 's|.*version* *\(.*\)$|\1|p' `
+	if test "$TMPVER" != "$OCAMLVERSION" ; then
+	    AC_MSG_RESULT(differs from ocamlc; ocamlopt.opt discarded.)
+	else
+	    AC_MSG_RESULT(ok)
+	    OCAMLOPT=$OCAMLOPTDOTOPT
+	fi
+    fi
+fi
+
+# ocamldep, ocamllex and ocamlyacc should also be present in the path
+AC_CHECK_PROG(OCAMLDEP,ocamldep,ocamldep,no)
+if test "$OCAMLDEP" = no ; then
+   AC_MSG_ERROR(Cannot find ocamldep.)
+else
+   AC_CHECK_PROG(OCAMLDEPDOTOPT,ocamldep.opt,ocamldep.opt,no)
+   if test "$OCAMLDEPDOTOPT" != no ; then
+      OCAMLDEP=$OCAMLDEPDOTOPT
+   fi
+fi
+
+AC_CHECK_PROG(OCAMLLEX,ocamllex,ocamllex,no)
+if test "$OCAMLLEX" = no ; then
+	AC_MSG_ERROR(Cannot find ocamllex.)
+else
+    AC_CHECK_PROG(OCAMLLEXDOTOPT,ocamllex.opt,ocamllex.opt,no)
+    if test "$OCAMLLEXDOTOPT" != no ; then
+	OCAMLLEX=$OCAMLLEXDOTOPT
+    fi
+fi
+
+AC_CHECK_PROG(OCAMLYACC,ocamlyacc,ocamlyacc,no)
+if test "$OCAMLYACC" = no ; then
+	AC_MSG_ERROR(Cannot find ocamlyacc.)
+fi
+
+AC_CHECK_PROG(OCAMLDOC,ocamldoc,ocamldoc,true)
+if test "$OCAMLDOC" = true ; then
+    AC_MSG_WARN(Cannot find ocamldoc)
+else
+    AC_CHECK_PROG(OCAMLDOCOPT,ocamldoc.opt,ocamldoc.opt,no)
+    if test "$OCAMLDOCOPT" != no ; then
+	OCAMLDOC=$OCAMLDOCOPT
+    fi
+fi
+
+
+#looking for ocamlgraph library
+
+LOCALOCAMLGRAPH=no
+
+AC_CHECK_FILE($OCAMLLIB/graph.cmi,OCAMLGRAPH=yes,OCAMLGRAPH=no)
+if test "$OCAMLGRAPH" = no ; then
+   AC_CHECK_FILE($OCAMLLIB/ocamlgraph/graph.cmi,OCAMLGRAPH=yes,OCAMLGRAPH=no)
+   if test "$OCAMLGRAPH" = no ; then	
+      AC_CHECK_FILE(ocamlgraph/src/sig.mli,OCAMLGRAPH=yes,OCAMLGRAPH=no)
+      if test "$OCAMLGRAPH" = no ; then	
+	 AC_MSG_ERROR(Cannot find ocamlgraph library. Please install the *libocamlgraph-ocaml-dev* Debian package - or use the GODI caml package system *http://godi.ocaml-programming.de/* - or compile from sources *http://ocamlgraph.lri.fr/*)
+      else
+	 OCAMLGRAPHLIB="-I ocamlgraph"
+	 OCAMLGRAPHVER=" in local subdir ocamlgraph"
+	 LOCALOCAMLGRAPH=yes
+      fi
+   else		  
+      OCAMLGRAPHLIB="-I +ocamlgraph"
+      OCAMLGRAPHVER=" in Ocaml lib, subdir ocamlgraph"
+   fi
+else
+   OCAMLGRAPHLIB=""
+   OCAMLGRAPHVER=" in Ocaml lib, main dir"
+fi
+
+# checking ocamlgraph version
+
+dnl AC_MSG_CHECKING(ocamlgraph version)
+dnl if $OCAMLC $OCAMLGRAPHLIB graph.cma config/check_ocamlgraph.ml > /dev/null 2>&1 && (test "$OCAMLBEST" = "byte" || $OCAMLOPT $OCAMLGRAPHLIB graph.cmxa config/check_ocamlgraph.ml > /dev/null 2>&1); then
+dnl    AC_MSG_RESULT(ok)
+dnl    OCAMLGRAPHVER="0.99"$OCAMLGRAPHVER
+dnl else
+dnl    AC_MSG_RESULT(failed)
+dnl    if test -d ocamlgraph; then
+dnl       AC_MSG_RESULT(Switching to local ocamlgraph)
+dnl       OCAMLGRAPHLIB="-I ocamlgraph"
+dnl       OCAMLGRAPHVER=" in local subdir ocamlgraph"
+dnl       LOCALOCAMLGRAPH=yes
+dnl    else
+dnl       AC_MSG_ERROR(You need ocamlgraph 0.99b or higher; you may need to compile from sources *http://ocamlgraph.lri.fr/*)
+dnl    fi
+dnl fi
+dnl rm -f config/check_ocamlgraph.cmo config/check_ocamlgraph.cmi config/check_ocamlgraph.cmx config/check_ocamlgraph$EXE
+dnl # checking local ocamlgraph compilation
+
+dnl if test "$LOCALOCAMLGRAPH" = yes; then
+dnl    AC_MSG_CHECKING(ocamlgraph compilation)
+dnl    if (cd ocamlgraph; ./configure && make) > /dev/null 2>&1; then
+dnl       AC_MSG_RESULT(ok)
+dnl    else
+dnl       AC_MSG_ERROR(cannot compile ocamlgraph in ocamlgraph)
+dnl    fi
+dnl fi
+
+# checking for lablgtk2
+AC_CHECK_FILE($OCAMLLIB/lablgtk2/lablgtk.cma,LABLGTK2=yes,LABLGTK2=no)
+# AC_CHECK_PROG(LABLGTK2,lablgtk2,yes,no) not always available (Win32)
+if test "$LABLGTK2" = yes ; then
+      INCLUDEGTK2="-I +lablgtk2"
+fi
+
+AC_CHECK_PROG(OCAMLWEB,ocamlweb,ocamlweb,true)
+
+# apron library
+default_apron=no
+APRONLIBS=
+AC_ARG_ENABLE(apron,[  --enable-apron=[no/yes]  use APRON library for abstract interpretation [default=$default_apron]],,enable_apron=$default_apron)
+
+if test "$enable_apron" = "yes" ; then
+   AC_CHECK_FILE(/usr/local/lib/apron.cmxa,APRONLIB="-I /usr/local/lib -I /usr/lib",APRONLIB=no)
+   if test "$APRONLIB" = no ; then	
+      AC_CHECK_FILE(/usr/lib/apron.cmxa,APRONLIB="-I /usr/lib -I /usr/local/lib",APRONLIB=no)
+      if test "$APRONLIB" = no ; then	
+	 AC_MSG_ERROR(Cannot find APRON library.)
+      fi		     
+   fi
+   APRONLIBS="-cclib ' -lpolka_caml -lpolkaMPQ -loct_caml -loctMPQ -lbox_caml -lboxMPQ -lapron_caml -lapron -lgmp_caml -lmpfr -lgmp -lbigarray -lcamlidl' bigarray.cmxa gmp.cmxa apron.cmxa box.cmxa polka.cmxa"
+   ATPCMO=atp/atp.cmo
+fi
+
+# Frama-C
+AC_CHECK_PROG(FRAMAC,frama-c,yes,no)
+
+# camlp4 
+AC_CHECK_PROG(CAMLP4O,camlp4o,camlp4o,no)
+if test "$CAMLP4O" = no ; then
+     AC_MSG_ERROR(Cannot find camlp4o.)
+fi
+CAMLP4LIB=`camlp4o -where`
+CAMLP4VERSION=`$CAMLP4O -v 2>&1 | sed -n -e 's|.*version *\(.*\)$|\1|p'`
+AC_MSG_CHECKING(camlp4 version)
+if test "$CAMLP4VERSION" != "$OCAMLVERSION" ; then
+     AC_MSG_ERROR(differs from ocaml version)
+else
+     AC_MSG_RESULT(ok)
+fi
+
+dnl AC_CHECK_PROG(CAMLP4OOPT,camlp4o.opt,camlp4o.opt,no)
+dnl if test "CAMLP4OOPT" != no ; then
+dnl      AC_MSG_CHECKING(camlp4o.opt version)
+dnl      TMPVERSION=`$CAMLP4OOPT -v 2>&1 |sed -n -e 's|.*version *\(.*\)$|\1|p'`
+dnl      if test "$TMPVERSION" != $CAMLP4VERSION ; then
+dnl 	  AC_MSG_RESULT(differs from camlp4o; camlp4o.opt discarded.)
+dnl      else
+dnl  	  AC_MSG_RESULT(ok)
+dnl  	  CAMLP4O=$CAMLP4OOPT
+dnl      fi
+dnl fi
+
+WHYFLOATS=
+
+# Coq
+AC_CHECK_PROG(COQC,coqc,coqc,no)
+if test "$COQC" = no ; then
+    COQ=no
+    AC_MSG_WARN(Cannot find coqc.)
+else
+    COQ=yes
+    AC_CHECK_PROG(COQDEP,coqdep,coqdep,true)
+    if test "$COQDEP" = true ; then
+	AC_MSG_ERROR(Cannot find coqdep.)
+    fi
+    COQLIB=`$COQC -where | sed -e 's|\\\|/|g' -e 's| |\\ |g'`
+    AC_MSG_CHECKING(Coq version)
+    COQVERSION=`$COQC -v | sed -n -e 's|.*version* *\([[^ ]]*\) .*$|\1|p' `
+
+    case $COQVERSION in
+    7.4*)
+	AC_MSG_RESULT($COQVERSION)
+	COQC7=$COQC
+	COQVER=v7
+	WHYLIBCOQ=lib/coq-v7
+	cp -f lib/coq-v7/WhyCoqDev.v lib/coq-v7/WhyCoqCompat.v;;
+    8.*|trunk)
+	AC_MSG_RESULT($COQVERSION)
+	COQC7="$COQC -v7"
+	COQC8=$COQC
+	COQVER=v8
+	WHYLIBCOQ=lib/coq
+	cp -f lib/coq-v7/WhyCoqDev.v lib/coq-v7/WhyCoqCompat.v
+	case $COQVERSION in
+	8.1*|8.2*|trunk)
+	  JESSIELIBCOQ=lib/coq/jessie_why.vo
+	  cp -f lib/coq/WhyCoqDev.v lib/coq/WhyCoqCompat.v
+          COQVER=v8.1
+          ;;
+	*)
+	  JESSIELIBCOQ=
+	  cp -f lib/coq/WhyCoq8.v lib/coq/WhyCoqCompat.v;;
+        esac
+	AC_MSG_CHECKING(Coq floating-point library)
+ 	case $COQVERSION in
+	   8.2*|trunk)
+ 	      if test -f "$COQLIB/user-contrib/AllFloat.vo"; then
+	        AC_MSG_RESULT(yes)
+	  	WHYFLOATS="lib/coq/WhyFloats.vo lib/coq/JessieFloats.vo"
+		COQFLOATSMSG=yes
+	      else
+	        AC_MSG_RESULT(no)
+	        COQFLOATSMSG="no (Coq library AllFloat.vo not found)"
+	      fi
+	      AC_MSG_CHECKING(Coq Gappa library)
+ 	      if test -f "$COQLIB/user-contrib/Gappa/Gappa_tactic.vo"; then
+	        AC_MSG_RESULT(yes)
+	  	WHYFLOATS="$WHYFLOATS lib/coq/JessieGappa.vo"
+		COQGAPPAMSG=yes
+	      else
+	        AC_MSG_RESULT(no)
+	        COQGAPPAMSG="no (Coq library Gappa_tactic.vo not found)"
+	      fi
+	      ;;
+	   *)
+	      COQFLOATSMSG="no (requires Coq version >= 8.2)"
+	      COQGAPPAMSG="no (requires Coq version >= 8.2)"
+	      ;;
+           esac
+	;;
+    *)
+	COQ=no
+	AC_MSG_WARN(You need Coq 7.4 or later; Coq discarded);;
+    esac
+fi
+
+# Alt-ergo
+dnl AC_CHECK_PROG(ALTERGO,alt-ergo,alt-ergo,no)
+dnl if test "$ALTERGO" = no ; then
+dnl    AC_CHECK_PROG(ERGO,ergo,ergo,no)
+dnl    if test "$ERGO" = no ; then
+dnl      ERGOBIN=alt-ergo
+dnl    else
+dnl      ERGOBIN=ergo
+dnl    fi
+dnl else
+dnl    ERGOBIN=alt-ergo
+dnl fi
+
+# PVS
+AC_PATH_PROG(PVSC,pvs,no)
+if test "$PVSC" = no ; then
+    PVS=no
+    AC_MSG_WARN(Cannot find PVS.)
+else
+    PVS=yes
+    PVSLIB=`pvs -where`/lib
+    if test "$PVSLIB" = /lib; then 
+       AC_MSG_WARN(PVS found but pvs -where did not work)
+       PVS=no; 
+    fi
+fi
+
+# Mizar
+AC_CHECK_PROG(MIZF,mizf,mizf,no)
+if test "$MIZF" = no; then
+    MIZAR=no
+    AC_MSG_WARN(Cannot find Mizar.)
+else
+    MIZAR=yes
+    AC_MSG_CHECKING(Mizar library)
+    if test -d "$MIZFILES"; then
+	MIZARLIB=$MIZFILES
+	AC_MSG_RESULT($MIZARLIB)
+    else if test -d /usr/local/lib/mizar; then
+	MIZARLIB=$MIZFILES
+	AC_MSG_RESULT($MIZARLIB)
+    else
+	AC_MSG_WARN(Cannot find Mizar library; please set \$MIZFILES)
+	MIZAR=no
+    fi
+    fi
+fi
+
+# substitutions to perform
+AC_SUBST(VERBOSEMAKE)
+AC_SUBST(EXE)
+AC_SUBST(STRIP)
+AC_SUBST(CPULIMIT)
+
+AC_SUBST(OCAMLC)
+AC_SUBST(OCAMLOPT)
+AC_SUBST(OCAMLDEP)
+AC_SUBST(OCAMLLEX)
+AC_SUBST(OCAMLYACC)
+AC_SUBST(OCAMLDOC)
+AC_SUBST(OCAMLBEST)
+AC_SUBST(OCAMLVERSION)
+AC_SUBST(OCAMLV)
+AC_SUBST(OCAMLLIB)
+AC_SUBST(OCAMLGRAPHLIB)
+AC_SUBST(LABLGTK2)
+AC_SUBST(INCLUDEGTK2)
+AC_SUBST(OCAMLWEB)
+# AC_SUBST(CAMLP4O)
+# AC_SUBST(CAMLP4LIB)
+
+AC_SUBST(enable_apron)
+AC_SUBST(APRONLIB)
+AC_SUBST(APRONLIBS)
+AC_SUBST(FRAMAC)
+AC_SUBST(ATPCMO)
+
+AC_SUBST(COQ)
+AC_SUBST(COQC7)
+AC_SUBST(COQC8)
+AC_SUBST(COQDEP)
+AC_SUBST(COQLIB)
+AC_SUBST(COQVER)
+AC_SUBST(WHYLIBCOQ)
+AC_SUBST(WHYFLOATS)
+AC_SUBST(JESSIELIBCOQ)
+
+# AC_SUBST(ERGOBIN)
+
+AC_SUBST(PVS)
+AC_SUBST(PVSC)
+AC_SUBST(PVSLIB)
+
+AC_SUBST(MIZAR)
+AC_SUBST(MIZF)
+AC_SUBST(MIZARLIB)
+
+AC_SUBST(FORPACK)
+
+# Finally create the Makefile from Makefile.in
+AC_OUTPUT(Makefile)
+dnl AC_OUTPUT(Makefile bench/bench)
+chmod a-w Makefile
+dnl chmod a+x bench/bench
+
+# Summary
+
+echo
+echo "                 Summary"
+echo "-----------------------------------------"
+echo "OCaml version           : $OCAMLVERSION"
+echo "OCaml library path      : $OCAMLLIB"
+echo "OcamlGraph lib          : $OCAMLGRAPHVER"
+echo "Verbose make            : $VERBOSEMAKE"
+echo "Abstract interpretation : $enable_apron"
+echo "Frama-C plugin          : $FRAMAC"
+if test "$enable_apron" = "yes" ; then
+   echo "    APRON lib           : $APRONLIB"
+fi
+echo "GWhy                    : $LABLGTK2"
+echo "Coq support             : $COQ"
+if test "$COQ" = "yes" ; then
+   echo "    Version             : $COQVER ($COQVERSION)"
+   if test "$JESSIELIBCOQ" = ""; then
+      echo "                        : (Jessie Coq proofs disabled, requires >= 8.1)"
+   fi
+   echo "    Lib                 : $COQLIB" 
+   echo "    Floats              : $COQFLOATSMSG"
+   echo "    Gappa               : $COQGAPPAMSG"
+fi
+# echo "Alt-ergo binary         : $ERGOBIN"
+echo "PVS support             : $PVS"
+if test "$PVS" = "yes" ; then
+   echo "    Bin                 : $PVSC"
+   echo "    Lib                 : $PVSLIB"
+fi
+echo "Mizar support           : $MIZAR"

src/hashcons.ml

+(**************************************************************************)
+(*                                                                        *)
+(*  Copyright (C) Jean-Christophe Filliatre                               *)
+(*                                                                        *)
+(*  This software is free software; you can redistribute it and/or        *)
+(*  modify it under the terms of the GNU Library General Public           *)
+(*  License version 2.1, with the special exception on linking            *)
+(*  described in file LICENSE.                                            *)
+(*                                                                        *)
+(*  This software 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.                  *)
+(*                                                                        *)
+(**************************************************************************)
+
+(*s Hash tables for hash-consing. (Some code is borrowed from the ocaml
+    standard library, which is copyright 1996 INRIA.) *)
+
+let gentag =
+  let r = ref 0 in
+  fun () -> incr r; !r
+
+module type HashedType =
+  sig
+    type node
+    val equal : node -> node -> bool
+    val hash : node -> int
+
+    type t
+    val node : t -> node
+  end
+
+module type S =
+  sig
+    type node
+    type t
+    val hashcons : node -> (node -> int -> t) -> t
+    val iter : (t -> unit) -> unit
+    val stats : unit -> int * int * int * int * int * int
+  end
+
+module Make(H : HashedType) : (S with type node = H.node and type t = H.t) = 
+struct
+
+  type node = H.node
+  type t = H.t
+
+  type table = {
+    mutable table : t Weak.t array;
+    mutable totsize : int;             (* sum of the bucket sizes *)
+    mutable limit : int;               (* max ratio totsize/table length *)
+  }
+
+  let emptybucket = Weak.create 0
+
+  let create sz =
+    let sz = if sz < 7 then 7 else sz in
+    let sz = if sz > Sys.max_array_length then Sys.max_array_length else sz in
+    {
+      table = Array.create sz emptybucket;
+      totsize = 0;
+      limit = 3;
+    }
+
+  let clear t =
+    for i = 0 to Array.length t.table - 1 do
+      t.table.(i) <- emptybucket
+    done;
+    t.totsize <- 0;
+    t.limit <- 3
+  
+  let fold f t init =
+    let rec fold_bucket i b accu =
+      if i >= Weak.length b then accu else
+      match Weak.get b i with
+      | Some v -> fold_bucket (i+1) b (f v accu)
+      | None -> fold_bucket (i+1) b accu
+    in
+    Array.fold_right (fold_bucket 0) t.table init
+
+  let count t =
+    let rec count_bucket i b accu =
+      if i >= Weak.length b then accu else
+      count_bucket (i+1) b (accu + (if Weak.check b i then 1 else 0))
+    in
+    Array.fold_right (count_bucket 0) t.table 0
+
+  let next_sz n = min (3*n/2 + 3) (Sys.max_array_length - 1)
+
+  let rec resize t =
+    let oldlen = Array.length t.table in
+    let newlen = next_sz oldlen in
+    if newlen > oldlen then begin
+      let newt = create newlen in
+      newt.limit <- t.limit + 100;          (* prevent resizing of newt *)
+      fold (fun d () -> add newt d (H.hash (H.node d))) t ();
+      t.table <- newt.table;
+      t.limit <- t.limit + 2;
+    end
+
+  and add t d hkey =
+    let index = hkey mod (Array.length t.table) in
+    let bucket = t.table.(index) in
+    let sz = Weak.length bucket in
+    let rec loop i =
+      if i >= sz then begin
+        let newsz = min (sz + 3) (Sys.max_array_length - 1) in
+        if newsz <= sz then 
+	  failwith "Hashcons.Make: hash bucket cannot grow more";
+        let newbucket = Weak.create newsz in
+        Weak.blit bucket 0 newbucket 0 sz;
+        Weak.set newbucket i (Some d);
+        t.table.(index) <- newbucket;
+        t.totsize <- t.totsize + (newsz - sz);
+        if t.totsize > t.limit * Array.length t.table then resize t;
+      end else begin
+        if Weak.check bucket i
+        then loop (i+1)
+        else Weak.set bucket i (Some d)
+      end
+    in
+    loop 0
+
+  let t = create 5003
+
+  let hashcons d f =
+    let hkey = H.hash d in