\documentclass{article}
\usepackage{axiom}
\begin{document}
\title{\$SPAD/src/interp hashcode.boot}
\author{The Axiom Team}
\maketitle
\begin{abstract}
\end{abstract}
\eject
\tableofcontents
\eject
\section{License}
<<license>>=
-- Copyright (c) 1991-2002, The Numerical ALgorithms Group Ltd.
-- All rights reserved.
--
-- Redistribution and use in source and binary forms, with or without
-- modification, are permitted provided that the following conditions are
-- met:
--
--     - Redistributions of source code must retain the above copyright
--       notice, this list of conditions and the following disclaimer.
--
--     - Redistributions in binary form must reproduce the above copyright
--       notice, this list of conditions and the following disclaimer in
--       the documentation and/or other materials provided with the
--       distribution.
--
--     - Neither the name of The Numerical ALgorithms Group Ltd. nor the
--       names of its contributors may be used to endorse or promote products
--       derived from this software without specific prior written permission.
--
-- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
-- IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
-- TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
-- PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
-- OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
-- EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
-- PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
-- PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
-- LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
-- NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
-- SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

@
<<*>>=
<<license>>

)package "BOOT"

-- Type hasher for old compiler style type names which produces a hash code
-- compatible with the asharp compiler.  Takes a hard error if the type
-- is parameterized, but has no constructor modemap.
getDomainHash dom == SPADCALL(CDR dom, (CAR dom).4)

hashType(type, percentHash) ==
	SYMBOLP type  =>
           type = '$ => percentHash
           type = "%" => percentHash
           hashString SYMBOL_-NAME type
        STRINGP type  => hashCombine(hashString type, 
   					hashString('"Enumeration"))
        type is ['QUOTE, val] => hashType(val, percentHash)
	type is [dom] => hashString SYMBOL_-NAME dom
	type is ['_:, ., type2] => hashType(type2, percentHash)
        isDomain type => getDomainHash type
	[op, :args] := type
	hash := hashString SYMBOL_-NAME op
	op = 'Mapping =>
		hash := hashString '"->"
		[retType, :mapArgs] := args
		for arg in mapArgs repeat
			hash := hashCombine(hashType(arg, percentHash), hash)
                retCode := hashType(retType, percentHash)
                EQL(retCode, $VoidHash) => hash
		hashCombine(retCode, hash)
	op = 'Enumeration =>
		for arg in args repeat
			hash := hashCombine(hashString(STRING arg), hash)
		hash
	op in $DomainsWithoutLisplibs =>
		for arg in args repeat
			hash := hashCombine(hashType(arg, percentHash), hash)
		hash

	cmm :=   CDDAR getConstructorModemap(op)
	cosig := CDR   GETDATABASE(op, 'COSIG)
	for arg in args for c in cosig for ct in cmm repeat
		if c then
			hash := hashCombine(hashType(arg, percentHash), hash)
		else
			hash := hashCombine(7, hash)
--           !!!   If/when asharp hashes values using their type, use instead
--			ctt := EQSUBSTLIST(args, $FormalMapVariableList, ct)
--			hash := hashCombine(hashType(ctt, percentHash), hash)


	hash

--The following are in cfuns.lisp
$hashModulus := 1073741789 			-- largest 30-bit prime

-- Produce a 30-bit hash code.  This function must produce the same codes
-- as the asharp string hasher in src/strops.c
hashString str ==
	h := 0
	for i in 0..#str-1 repeat
		j := CHAR_-CODE char str.i
		h := LOGXOR(h, ASH(h, 8))
		h := h + j + 200041
		h := LOGAND(h, 1073741823)	-- 0x3FFFFFFF
	REM(h, $hashModulus)

-- Combine two hash codes to make a new one.  Must be the same as in
-- the hashCombine function in aslib/runtime.as in asharp.
hashCombine(hash1, hash2) ==
	 MOD(ASH(LOGAND(hash2, 16777215), 6) + hash1, $hashModulus)


$VoidHash := hashString '"Void"


-- following two lines correct bad coSig properties due to SubsetCategory
--putConstructorProperty('LocalAlgebra,'coSig,'(NIL T T T))
--putConstructorProperty('Localize,'coSig,'(NIL T T T))
@
\eject
\begin{thebibliography}{99}
\bibitem{1} nothing
\end{thebibliography}
\end{document}