ref: 63392be12a1a657419af2d2966995428721f18f3
dir: /appl/cmd/sh/mpexpr.b/
implement Shellbuiltin;
include "sys.m";
sys: Sys;
include "draw.m";
include "keyring.m";
keyring: Keyring;
IPint: import keyring;
include "sh.m";
sh: Sh;
Listnode, Context: import sh;
myself: Shellbuiltin;
Big: type ref IPint;
Zero: Big;
One: Big;
initbuiltin(ctxt: ref Context, shmod: Sh): string
{
sys = load Sys Sys->PATH;
keyring = load Keyring Keyring->PATH;
sh = shmod;
myself = load Shellbuiltin "$self";
if (myself == nil)
ctxt.fail("bad module", sys->sprint("expr: cannot load self: %r"));
Zero = IPint.inttoip(0);
One = IPint.inttoip(1);
ctxt.addsbuiltin("expr", myself);
ctxt.addbuiltin("ntest", myself);
return nil;
}
whatis(nil: ref Sh->Context, nil: Sh, nil: string, nil: int): string
{
return nil;
}
getself(): Shellbuiltin
{
return myself;
}
EQ, GT, LT, GE, LE, PLUS, MINUS, DIVIDE, AND, TIMES, MOD,
OR, XOR, UMINUS, SHL, SHR, NOT, BNOT, NEQ, REP, SEQ,
BITS, EXPMOD, INVERT, RAND, EXP: con iota;
runbuiltin(ctxt: ref Sh->Context, nil: Sh,
cmd: list of ref Sh->Listnode, nil: int): string
{
case (hd cmd).word {
"ntest" =>
if (len cmd != 2)
ctxt.fail("usage", "usage: ntest n");
if(strtoip(ctxt, (hd tl cmd).word).eq(Zero))
return "false";
}
return nil;
}
runsbuiltin(ctxt: ref Sh->Context, nil: Sh,
cmd: list of ref Sh->Listnode): list of ref Listnode
{
# only one sbuiltin: expr.
stk: list of Big;
lastop := -1;
lastn := -1;
lastname := "";
radix: int;
(cmd, radix) = opts(ctxt, tl cmd);
for (; cmd != nil; cmd = tl cmd) {
w := (hd cmd).word;
op := -1;
nops := 2;
case w {
"+" =>
op = PLUS;
"-" =>
op = MINUS;
"x" or "*" or "×" =>
op = TIMES;
"/" =>
op = DIVIDE;
"%" =>
op = MOD;
"and" =>
op = AND;
"or" =>
op = OR;
"xor" =>
op = XOR;
"_"=>
(op, nops) = (UMINUS, 1);
"<<" or "shl" =>
op = SHL;
">>" or "shr" =>
op = SHR;
"=" or "==" or "eq" =>
op = EQ;
"!=" or "neq" =>
op = NEQ;
">" or "gt" =>
op = GT;
"<" or "lt" =>
op = LT;
">=" or "ge" =>
op = GE;
"<=" or "le" =>
op = LE;
"!" or "not" =>
(op, nops) = (NOT, 1);
"~" =>
(op, nops) = (BNOT, 1);
"rep" =>
(op, nops) = (REP, 0);
"seq" =>
(op, nops) = (SEQ, 2);
"bits" =>
(op, nops) = (BITS, 1);
"expmod" =>
(op, nops) = (EXPMOD, 3);
"invert" =>
(op, nops) = (INVERT, 2);
"rand" =>
(op, nops) = (RAND, 1);
"exp" or "xx" or "**" =>
(op, nops) = (EXP, 2);
}
if (op == -1){
if (w == nil || (w[0] != '-' && (w[0] < '0' || w[0] > '9')))
ctxt.fail("usage", sys->sprint("expr: unknown operator '%s'", w));
stk = strtoip(ctxt, w) :: stk;
}else
stk = operator(ctxt, stk, op, nops, lastop, lastn, w, lastname);
lastop = op;
lastn = nops;
lastname = w;
}
r: list of ref Listnode;
for (; stk != nil; stk = tl stk)
r = ref Listnode(nil, iptostr(hd stk, radix)) :: r;
return r;
}
opts(ctxt: ref Context, cmd: list of ref Listnode): (list of ref Listnode, int)
{
if (cmd == nil)
return (nil, 10);
w := (hd cmd).word;
if (len w < 2)
return (cmd, 10);
if (w[0] != '-' || (w[1] >= '0' && w[1] <= '9'))
return (cmd, 10);
if (w[1] != 'r')
ctxt.fail("usage", "usage: expr [-r radix] [arg...]");
if (len w > 2)
w = w[2:];
else {
if (tl cmd == nil)
ctxt.fail("usage", "usage: expr [-r radix] [arg...]");
cmd = tl cmd;
w = (hd cmd).word;
}
r := int w;
if (r <= 0 || (r > 36 && r != 64))
ctxt.fail("usage", "expr: invalid radix " + string r);
return (tl cmd, int w);
}
operator(ctxt: ref Context, stk: list of Big, op, nops, lastop, lastn: int,
opname, lastopname: string): list of Big
{
al: list of Big;
for (i := 0; i < nops; i++) {
if (stk == nil)
ctxt.fail("empty stack",
sys->sprint("expr: empty stack on op '%s'", opname));
al = hd stk :: al;
stk = tl stk;
}
return oper(ctxt, al, op, lastop, lastn, lastopname, stk);
}
# args are in reverse order
oper(ctxt: ref Context, args: list of Big, op, lastop, lastn: int,
lastopname: string, stk: list of Big): list of Big
{
if (op == REP) {
if (lastop == -1 || lastop == SEQ || lastn != 2)
ctxt.fail("usage", "expr: bad operator for rep");
if (stk == nil || tl stk == nil)
return stk;
while (tl stk != nil)
stk = operator(ctxt, stk, lastop, 2, -1, -1, lastopname, nil);
return stk;
}
n3 := Zero;
n2 := Zero;
n1 := hd args;
if (tl args != nil){
n2 = hd tl args;
if(tl tl args != nil)
n3 = hd tl tl args;
}
r := Zero;
case op {
EQ => r = mki(n1.eq(n2));
NEQ => r = mki(!n1.eq(n2));
GT => r = mki(n1.cmp(n2) > 0);
LT => r = mki(n1.cmp(n2) < 0);
GE => r = mki(n1.cmp(n2) >= 0);
LE => r = mki(n1.cmp(n2) <= 0);
PLUS => r = n1.add(n2);
MINUS => r = n1.sub(n2);
NOT => r = mki(n1.eq(Zero));
DIVIDE =>
if (n2.eq(Zero))
ctxt.fail("divide by zero", "expr: division by zero");
(r, nil) = n1.div(n2);
MOD =>
if (n2.eq(Zero))
ctxt.fail("divide by zero", "expr: division by zero");
(nil, r) = n1.div(n2);
TIMES =>
r = n1.mul(n2);
AND => r = bitop(ipand, n1, n2);
OR => r = bitop(ipor, n1, n2);
XOR => r = bitop(ipxor, n1, n2);
UMINUS => r = n1.neg();
BNOT => r = n1.neg().sub(One);
SHL => r = n1.shl(n2.iptoint());
SHR => r = n1.shr(n2.iptoint());
SEQ => return seq(n1, n2, stk);
BITS => r = mki(n1.bits());
EXPMOD => r = n1.expmod(n2, n3);
EXP => r = n1.expmod(n2, nil);
RAND => r = IPint.random(0, n1.iptoint());
INVERT => r = n1.invert(n2);
}
return r :: stk;
}
# won't work if op(0, 0) != 0
bitop(op: ref fn(n1, n2: Big): Big, n1, n2: Big): Big
{
bits := max(n1.bits(), n2.bits());
return signedmag(op(twoscomp(n1, bits), twoscomp(n2, bits)), bits);
}
onebits(n: int): Big
{
return One.shl(n).sub(One);
}
# return a two's complement version of n,
# sign-extended to b bits if negative.
# sign bit is at 1<<b.
twoscomp(n: Big, b: int): Big
{
if(n.cmp(Zero) >= 0)
return n;
return n.not().ori(onebits(b).xor(onebits(n.bits()))).add(One);
}
# return conventional representation of n,
# where n is in two's complement form in b bits.
signedmag(n: Big, b: int): Big
{
if(n.and(One.shl(b)).eq(Zero))
return n;
return n.sub(One).not().and(onebits(b)).neg();
}
max(x, y: int): int
{
if(x > y)
return x;
else
return y;
}
seq(n1, n2: Big, stk: list of Big): list of Big
{
incr := mki(1);
if (n2.cmp(n1) < 0)
incr = mki(-1);
for (; !n1.eq(n2); n1 = n1.add(incr))
stk = n1 :: stk;
return n1 :: stk;
}
strtoip(ctxt: ref Context, s: string): Big
{
t := s;
if (neg := s[0] == '-')
s = s[1:];
radix := 10;
for (i := 0; i < len s && i < 3; i++) {
if (s[i] == 'r') {
radix = int s;
s = s[i+1:];
break;
}
}
if (radix == 10)
return IPint.strtoip(s, 10);
if (radix == 0 || (radix > 36 && radix != 64))
ctxt.fail("usage", "expr: bad number " + t);
n := Zero;
case radix {
10 or 16 or 64 =>
n = IPint.strtoip(s, radix);
* =>
r := mki(radix);
for (i = 0; i < len s; i++) {
if ('0' <= s[i] && s[i] <= '9')
n = n.mul(r).add(mki(s[i] - '0'));
else if ('a' <= s[i] && s[i] < 'a' + radix - 10)
n = n.mul(r).add(mki(s[i] - 'a' + 10));
else if ('A' <= s[i] && s[i] < 'A' + radix - 10)
n = n.mul(r).add(mki(s[i] - 'A' + 10));
else
break;
}
}
if(neg)
return n.neg();
return n;
}
iptostr(n: Big, radix: int): string
{
neg := n.cmp(Zero) < 0;
t: string;
case radix {
2 or 4 or 16 or 32 =>
b := n.iptobebytes();
rbits := log2(radix);
bits := roundup(n.bits(), rbits);
for(i := bits - rbits; i >= 0; i -= rbits){
d := 0;
for(j := 0; j < rbits; j++)
d |= getbit(b, i+j) << j;
t[len t] = digit(d);
}
10 =>
return n.iptostr(radix);
64 =>
t = n.iptostr(radix);
if(neg)
t = t[1:];
* =>
if(neg)
n = n.neg();
r := mki(radix);
s: string;
do{
d: Big;
(n, d) = n.div(r);
s[len s] = digit(d.iptoint());
}while(n.cmp(Zero) > 0);
t = s;
for (i := len s - 1; i >= 0; i--)
t[len s - 1 - i] = s[i];
}
t = string radix + "r" + t;
if (neg)
return "-" + t;
return t;
}
mki(i: int): Big
{
return IPint.inttoip(i);
}
b2s(b: array of byte): string
{
s := "";
for(i := 0; i < len b; i++)
s += sys->sprint("%.2x", int b[i]);
return s;
}
# count from least significant bit.
getbit(b: array of byte, bit: int): int
{
if((i := bit >> 3) >= len b){
return 0;
}else{
return (int b[len b - i -1] >> (bit&7)) & 1;
}
}
digit(d: int): int
{
if(d < 10)
return '0' + d;
else
return 'a' + d - 10;
}
log2(x: int): int
{
case x {
2 => return 1;
4 => return 2;
8 => return 3;
16 => return 4;
32 => return 5;
}
return 0;
}
roundup(n: int, m: int): int
{
return m*((n+m-1)/m);
}
# these functions are to get around the fact that the limbo compiler isn't
# currently considering ref fn(x: self X, ...) compatible with ref fn(x: X, ...).
ipand(n1, n2: Big): Big
{
return n1.and(n2);
}
ipor(n1, n2: Big): Big
{
return n1.ori(n2);
}
ipxor(n1, n2: Big): Big
{
return n1.xor(n2);
}