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(* Copyright (C) 2011 Free Software Foundation, Inc. *)
(* This file is part of GNU Modula-2.
GNU Modula-2 is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.
GNU Modula-2 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 General Public License
for more details.
You should have received a copy of the GNU General Public License along
with gm2; see the file COPYING. If not, write to the Free Software
Foundation, 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA. *)
MODULE integer ;
(*
Title : integer
Author : Gaius Mulley
System : GNU Modula-2
Date : Fri May 18 17:05:36 2012
Revision : $Version$
Description: simple test module to test the principles of catching signed and unsigned
integer arithmetic overflow.
*)
FROM SYSTEM IMPORT ADDRESS ;
FROM libc IMPORT printf ;
FROM DynamicStrings IMPORT String, InitString, string, KillString, InitString ;
CONST
Verbose = TRUE ;
SizeOfIntAndLongSame = TRUE ;
PROCEDURE ssub (i, j: INTEGER) ;
BEGIN
IF ((j>0) AND (i < MIN(INTEGER)+j)) OR
((j<0) AND (i > MAX(INTEGER)+j))
THEN
expecting(overflow, 'signed subtraction')
ELSE
expecting(none, 'signed subtraction')
END
END ssub ;
PROCEDURE sadd (i, j: INTEGER) ;
BEGIN
IF ((j = MAX(INTEGER) AND (i > 0))) OR
((i = MAX(INTEGER) AND (j > 0))) OR
((j>0) AND (i > MAX(INTEGER)-j)) OR
((j<0) AND (i < MIN(INTEGER)-j))
THEN
expecting(overflow, 'signed addition')
ELSE
expecting(none, 'signed addition')
END
END sadd ;
(*
smallMult -
*)
PROCEDURE smallMult (i, j: INTEGER) ;
BEGIN
IF i>0
THEN
IF j>0
THEN
IF i>maxInt DIV j
THEN
expecting(overflow, 'signed mult')
ELSE
expecting(none, 'signed mult')
END
ELSE
IF j<minInt DIV i
THEN
expecting(overflow, 'signed mult')
ELSE
expecting(none, 'signed mult')
END
END
ELSE
IF j>0
THEN
IF i<minInt DIV j
THEN
expecting(overflow, 'signed mult')
ELSE
expecting(none, 'signed mult')
END
ELSE
IF (i#0) AND (j<maxInt DIV i)
THEN
expecting(overflow, 'signed mult')
ELSE
expecting(none, 'signed mult')
END
END
END
END smallMult ;
(*
smult -
*)
PROCEDURE smult (i, j: INTEGER) ;
VAR
li, lj, lt: LONGINT ;
BEGIN
IF SizeOfIntAndLongSame OR (SIZE(LONGINT)=SIZE(INTEGER))
THEN
smallMult(i, j)
ELSE
li := i ;
lj := j ;
lt := li * lj ;
IF (lt<VAL(LONGINT, minInt)) OR (lt>VAL(LONGINT, maxInt))
THEN
expecting(overflow, 'signed multiply')
ELSE
expecting(none, 'signed multiply')
END
END
END smult ;
(*
sneg -
*)
PROCEDURE sneg (i: INTEGER) ;
BEGIN
IF i=minInt
THEN
expecting(overflow, 'signed negate')
ELSE
expecting(none, 'signed negate')
END
END sneg ;
(*
passed -
*)
PROCEDURE expecting (e: error; a: ARRAY OF CHAR) ;
VAR
s: String ;
t: ADDRESS ;
BEGIN
WITH test[testNo] DO
IF expected#e
THEN
s := InitString(a) ;
t := string(s) ;
printf("test %s (%d) has failed\n", t, testNo) ;
s := KillString(s)
ELSIF Verbose
THEN
s := InitString(a) ;
t := string(s) ;
printf("test %s (%d) has passed\n", t, testNo) ;
s := KillString(s)
END
END
END expecting ;
(*
doTest -
*)
PROCEDURE doTest ;
BEGIN
WITH test[testNo] DO
CASE op OF
iadd : sadd(l, r) |
isub : ssub(l, r) |
ineg : sneg(l) |
imult: smult(l, r) |
idiv : |
imod : |
END
END
END doTest ;
(*
doTests -
*)
PROCEDURE doTests ;
BEGIN
testNo := 0 ;
WHILE testNo<=maxTest DO
doTest ;
INC(testNo)
END
END doTests ;
CONST
maxTest = 25 ;
maxInt = MAX(INTEGER) ;
minInt = MIN(INTEGER) ;
TYPE
opcode = (iadd, isub, ineg, imult, idiv, imod) ;
error = (overflow, underflow, none) ;
case = RECORD
l, r : INTEGER ;
op : opcode ;
expected: error ;
END ;
cases = ARRAY [0..maxTest] OF case ;
VAR
test : cases ;
testNo: CARDINAL ;
BEGIN
test := cases{{minInt, 0, ineg, overflow},
(* 1 *)
{maxInt, 0, ineg, none},
{minInt DIV 2, minInt DIV 2, iadd, none},
{minInt DIV 2, minInt DIV 2-1, iadd, overflow},
{maxInt DIV 2, maxInt DIV 2, iadd, none},
(* 4 *)
{maxInt DIV 2, maxInt DIV 2+1, iadd, none},
{maxInt DIV 2+1, maxInt DIV 2+1, iadd, overflow},
{maxInt, 1, iadd, overflow},
{maxInt, 0, iadd, none},
(* 8 *)
{minInt, -1, iadd, overflow},
{minInt, 0, iadd, none},
{-1, maxInt, isub, none},
{-2, maxInt, isub, overflow},
(* 12 *)
{minInt, 1, isub, overflow},
{minInt, 0, isub, none},
{maxInt, -2, isub, overflow},
{maxInt, minInt, isub, overflow},
(* 16 *)
{0, maxInt, isub, none},
{0, minInt, isub, overflow},
{-1, maxInt, isub, none},
{-2, maxInt, isub, overflow},
(* 20 *)
{maxInt, 2, imult, overflow},
{maxInt DIV 2, 2, imult, none},
{minInt DIV 2, 2, imult, none},
{minInt DIV 2-1, 2, imult, overflow},
(* 24 *)
{maxInt DIV 3, 3, imult, none},
{minInt DIV 3, 3, imult, none}
} ;
doTests
END integer.
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