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/*
* $Id: math.c,v 2.11 1996/10/15 20:16:35 hzoli Exp $
*
* math.c - mathematical expression evaluation
*
* This file is part of zsh, the Z shell.
*
* Copyright (c) 1992-1996 Paul Falstad
* All rights reserved.
*
* Permission is hereby granted, without written agreement and without
* license or royalty fees, to use, copy, modify, and distribute this
* software and to distribute modified versions of this software for any
* purpose, provided that the above copyright notice and the following
* two paragraphs appear in all copies of this software.
*
* In no event shall Paul Falstad or the Zsh Development Group be liable
* to any party for direct, indirect, special, incidental, or consequential
* damages arising out of the use of this software and its documentation,
* even if Paul Falstad and the Zsh Development Group have been advised of
* the possibility of such damage.
*
* Paul Falstad and the Zsh Development Group specifically disclaim any
* warranties, including, but not limited to, the implied warranties of
* merchantability and fitness for a particular purpose. The software
* provided hereunder is on an "as is" basis, and Paul Falstad and the
* Zsh Development Group have no obligation to provide maintenance,
* support, updates, enhancements, or modifications.
*
*/
#include "zsh.h"
static char *ptr;
static long yyval;
static LV yylval;
static int mlevel = 0;
/* != 0 means recognize unary plus, minus, etc. */
static int unary = 1;
/* LR = left-to-right associativity *
* RL = right-to-left associativity *
* BOO = short-circuiting boolean */
#define LR 0
#define RL 1
#define BOOL 2
#define M_INPAR 0
#define M_OUTPAR 1
#define NOT 2
#define COMP 3
#define POSTPLUS 4
#define POSTMINUS 5
#define UPLUS 6
#define UMINUS 7
#define AND 8
#define XOR 9
#define OR 10
#define MUL 11
#define DIV 12
#define MOD 13
#define PLUS 14
#define MINUS 15
#define SHLEFT 16
#define SHRIGHT 17
#define LES 18
#define LEQ 19
#define GRE 20
#define GEQ 21
#define DEQ 22
#define NEQ 23
#define DAND 24
#define DOR 25
#define DXOR 26
#define QUEST 27
#define COLON 28
#define EQ 29
#define PLUSEQ 30
#define MINUSEQ 31
#define MULEQ 32
#define DIVEQ 33
#define MODEQ 34
#define ANDEQ 35
#define XOREQ 36
#define OREQ 37
#define SHLEFTEQ 38
#define SHRIGHTEQ 39
#define DANDEQ 40
#define DOREQ 41
#define DXOREQ 42
#define COMMA 43
#define EOI 44
#define PREPLUS 45
#define PREMINUS 46
#define NUM 47
#define ID 48
#define POWER 49
#define CID 50
#define POWEREQ 51
#define TOKCOUNT 52
/* precedences */
static int prec[TOKCOUNT] =
{
1, 137, 2, 2, 2,
2, 2, 2, 4, 5,
6, 8, 8, 8, 9,
9, 3, 3, 10, 10,
10, 10, 11, 11, 12,
13, 13, 14, 14, 15,
15, 15, 15, 15, 15,
15, 15, 15, 15, 15,
15, 15, 15, 16, 200,
2, 2, 0, 0, 7,
0, 15
};
#define TOPPREC 16
#define ARGPREC (TOPPREC-1)
static int type[TOKCOUNT] =
{
LR, LR, RL, RL, RL,
RL, RL, RL, LR, LR,
LR, LR, LR, LR, LR,
LR, LR, LR, LR, LR,
LR, LR, LR, LR, BOOL,
BOOL, LR, RL, RL, RL,
RL, RL, RL, RL, RL,
RL, RL, RL, RL, RL,
BOOL, BOOL, RL, RL, RL,
RL, RL, LR, LR, RL,
LR, RL
};
#define LVCOUNT 32
/* list of lvalues (variables) */
static int lvc;
static char **lvals;
/**/
int
zzlex(void)
{
int cct = 0;
for (;; cct = 0)
switch (*ptr++) {
case '+':
if (*ptr == '+' && (unary || !ialnum(*ptr))) {
ptr++;
return (unary) ? PREPLUS : POSTPLUS;
}
if (*ptr == '=') {
unary = 1;
ptr++;
return PLUSEQ;
}
return (unary) ? UPLUS : PLUS;
case '-':
if (*ptr == '-' && (unary || !ialnum(*ptr))) {
ptr++;
return (unary) ? PREMINUS : POSTMINUS;
}
if (*ptr == '=') {
unary = 1;
ptr++;
return MINUSEQ;
}
return (unary) ? UMINUS : MINUS;
case '(':
unary = 1;
return M_INPAR;
case ')':
return M_OUTPAR;
case '!':
if (*ptr == '=') {
unary = 1;
ptr++;
return NEQ;
}
return NOT;
case '~':
return COMP;
case '&':
unary = 1;
if (*ptr == '&') {
if (*++ptr == '=') {
ptr++;
return DANDEQ;
}
return DAND;
} else if (*ptr == '=') {
ptr++;
return ANDEQ;
}
return AND;
case '|':
unary = 1;
if (*ptr == '|') {
if (*++ptr == '=') {
ptr++;
return DOREQ;
}
return DOR;
} else if (*ptr == '=') {
ptr++;
return OREQ;
}
return OR;
case '^':
unary = 1;
if (*ptr == '^') {
if (*++ptr == '=') {
ptr++;
return DXOREQ;
}
return DXOR;
} else if (*ptr == '=') {
ptr++;
return XOREQ;
}
return XOR;
case '*':
unary = 1;
if (*ptr == '*') {
if (*++ptr == '=') {
ptr++;
return POWEREQ;
}
return POWER;
}
if (*ptr == '=') {
ptr++;
return MULEQ;
}
return MUL;
case '/':
unary = 1;
if (*ptr == '=') {
ptr++;
return DIVEQ;
}
return DIV;
case '%':
unary = 1;
if (*ptr == '=') {
ptr++;
return MODEQ;
}
return MOD;
case '<':
unary = 1;
if (*ptr == '<') {
if (*++ptr == '=') {
ptr++;
return SHLEFTEQ;
}
return SHLEFT;
} else if (*ptr == '=') {
ptr++;
return LEQ;
}
return LES;
case '>':
unary = 1;
if (*ptr == '>') {
if (*++ptr == '=') {
ptr++;
return SHRIGHTEQ;
}
return SHRIGHT;
} else if (*ptr == '=') {
ptr++;
return GEQ;
}
return GRE;
case '=':
unary = 1;
if (*ptr == '=') {
ptr++;
return DEQ;
}
return EQ;
case '$':
unary = 0;
yyval = mypid;
return NUM;
case '?':
if (unary) {
yyval = lastval;
unary = 0;
return NUM;
}
unary = 1;
return QUEST;
case ':':
unary = 1;
return COLON;
case ',':
unary = 1;
return COMMA;
case '\0':
unary = 1;
ptr--;
return EOI;
case '[':
unary = 0;
{
int base = zstrtol(ptr, &ptr, 10);
if (*ptr == ']')
ptr++;
yyval = zstrtol(ptr, &ptr, lastbase = base);
return NUM;
}
case ' ':
case '\t':
case '\n':
break;
case '0':
if (*ptr == 'x' || *ptr == 'X') {
unary = 0;
/* Should we set lastbase here? */
yyval = zstrtol(++ptr, &ptr, lastbase = 16);
return NUM;
}
/* Fall through! */
default:
if (idigit(*--ptr)) {
unary = 0;
yyval = zstrtol(ptr, &ptr, 10);
if (*ptr == '#') {
ptr++;
yyval = zstrtol(ptr, &ptr, lastbase = yyval);
}
return NUM;
}
if (*ptr == '#') {
if (*++ptr == '\\') {
ptr++;
yyval = *ptr == Meta ? *++ptr ^ 32 : *ptr;
ptr++;
unary = 0;
return NUM;
}
cct = 1;
}
if (iident(*ptr)) {
char *p, q;
p = ptr;
if (lvc == LVCOUNT) {
zerr("too many identifiers (complain to author)", NULL, 0);
return EOI;
}
unary = 0;
while (iident(*++ptr));
if (*ptr == '[') {
int l;
for (ptr++, l = 1; *ptr && l; ptr++) {
if (*ptr == '[')
l++;
if (*ptr == ']')
l--;
if (*ptr == '\\' && ptr[1])
ptr++;
}
}
q = *ptr;
*ptr = '\0';
lvals[yylval = lvc++] = ztrdup(p);
*ptr = q;
return cct ? CID : ID;
}
else if (cct) {
yyval = poundgetfn(NULL);
unary = 0;
return NUM;
}
return EOI;
}
}
/* the value stack */
#define STACKSZ 100
int mtok; /* last token */
int sp = -1; /* stack pointer */
struct mathvalue {
LV lval;
long val;
};
static struct mathvalue *stack;
static void push _((long val, LV lval));
static void
push(long val, LV lval)
{
if (sp == STACKSZ - 1)
zerr("stack overflow", NULL, 0);
else
sp++;
stack[sp].val = val;
stack[sp].lval = lval;
}
/**/
long
getcvar(LV s)
{
char *t;
if (!(t = getsparam(lvals[s])))
return 0;
return STOUC(*t == Meta ? t[1] ^ 32 : *t);
}
/**/
long
setvar(LV s, long v)
{
if (s == -1 || s >= lvc) {
zerr("lvalue required", NULL, 0);
return 0;
}
if (noeval)
return v;
setiparam(lvals[s], v);
return v;
}
/**/
int
notzero(long a)
{
if (a == 0) {
zerr("division by zero", NULL, 0);
return 0;
}
return 1;
}
/* macro to pop two values off the value stack */
#define pop2() { \
if (sp < 1) { \
zerr("bad math expression: unbalanced stack", NULL, 0); \
return; \
} \
b = stack[sp--].val; \
a = stack[sp--].val; \
}
/* macro to pop three values off the value stack */
#define pop3() { \
if (sp < 2) { \
zerr("bad math expression: unbalanced stack", NULL, 0); \
return; \
} \
c = stack[sp--].val; \
b = stack[sp--].val; \
a = stack[sp--].val; \
}
#define nolval() {stack[sp].lval= -1;}
#define pushv(X) { push(X,-1); }
#define pop2lv() { pop2() lv = stack[sp+1].lval; }
#define set(X) { push(setvar(lv,X),lv); }
/**/
void
op(int what)
{
long a, b, c;
LV lv;
if (sp < 0) {
zerr("bad math expression: stack empty", NULL, 0);
return;
}
switch (what) {
case NOT:
stack[sp].val = !stack[sp].val;
nolval();
break;
case COMP:
stack[sp].val = ~stack[sp].val;
nolval();
break;
case POSTPLUS:
(void)setvar(stack[sp].lval, stack[sp].val + 1);
break;
case POSTMINUS:
(void)setvar(stack[sp].lval, stack[sp].val - 1);
break;
case UPLUS:
nolval();
break;
case UMINUS:
stack[sp].val = -stack[sp].val;
nolval();
break;
case AND:
pop2();
pushv(a & b);
break;
case XOR:
pop2();
pushv(a ^ b);
break;
case OR:
pop2();
pushv(a | b);
break;
case MUL:
pop2();
pushv(a * b);
break;
case DIV:
pop2();
if (notzero(b))
pushv(a / b);
break;
case MOD:
pop2();
if (notzero(b))
pushv(a % b);
break;
case PLUS:
pop2();
pushv(a + b);
break;
case MINUS:
pop2();
pushv(a - b);
break;
case SHLEFT:
pop2();
pushv(a << b);
break;
case SHRIGHT:
pop2();
pushv(a >> b);
break;
case LES:
pop2();
pushv((long)(a < b));
break;
case LEQ:
pop2();
pushv((long)(a <= b));
break;
case GRE:
pop2();
pushv((long)(a > b));
break;
case GEQ:
pop2();
pushv((long)(a >= b));
break;
case DEQ:
pop2();
pushv((long)(a == b));
break;
case NEQ:
pop2();
pushv((long)(a != b));
break;
case DAND:
pop2();
pushv((long)(a && b));
break;
case DOR:
pop2();
pushv((long)(a || b));
break;
case DXOR:
pop2();
pushv((long)((a && !b) || (!a && b)));
break;
case QUEST:
pop3();
pushv((a) ? b : c);
break;
case COLON:
break;
case EQ:
pop2();
lv = stack[sp + 1].lval;
set(b);
break;
case PLUSEQ:
pop2lv();
set(a + b);
break;
case MINUSEQ:
pop2lv();
set(a - b);
break;
case MULEQ:
pop2lv();
set(a * b);
break;
case DIVEQ:
pop2lv();
if (notzero(b))
set(a / b);
break;
case MODEQ:
pop2lv();
if (notzero(b))
set(a % b);
break;
case ANDEQ:
pop2lv();
set(a & b);
break;
case XOREQ:
pop2lv();
set(a ^ b);
break;
case OREQ:
pop2lv();
set(a | b);
break;
case SHLEFTEQ:
pop2lv();
set(a << b);
break;
case SHRIGHTEQ:
pop2lv();
set(a >> b);
break;
case DANDEQ:
pop2lv();
set((long)(a && b));
break;
case DOREQ:
pop2lv();
set((long)(a || b));
break;
case DXOREQ:
pop2lv();
set((long)((a && !b) || (!a && b)));
break;
case COMMA:
pop2();
pushv(b);
break;
case PREPLUS:
stack[sp].val = setvar(stack[sp].lval,
stack[sp].val + 1);
break;
case PREMINUS:
stack[sp].val = setvar(stack[sp].lval,
stack[sp].val - 1);
break;
case POWER:
pop2();
if (b < 0) {
zerr("can't handle negative exponents", NULL, 0);
return;
}
for (c = 1; b--; c *= a);
pushv(c);
break;
case POWEREQ:
pop2lv();
if (b < 0) {
zerr("can't handle negative exponents", NULL, 0);
return;
}
for (c = 1; b--; c *= a);
set(c);
break;
default:
zerr("out of integers", NULL, 0);
return;
}
}
/**/
void
bop(int tk)
{
switch (tk) {
case DAND:
case DANDEQ:
if (!stack[sp].val)
noeval++;
break;
case DOR:
case DOREQ:
if (stack[sp].val)
noeval++;
break;
};
}
/**/
long
mathevall(char *s, int prek, char **ep)
{
int t0;
int xlastbase, xnoeval, xunary, xlvc;
char *xptr;
long xyyval;
LV xyylval;
char **xlvals = 0;
int xsp;
struct mathvalue *xstack = 0;
long ret;
xlastbase = xnoeval = xunary = xlvc = xyyval = xyylval = xsp = 0;
xptr = NULL;
if (mlevel++) {
xlastbase = lastbase;
xnoeval = noeval;
xunary = unary;
xlvc = lvc;
xptr = ptr;
xyyval = yyval;
xyylval = yylval;
xlvals = lvals;
xsp = sp;
xstack = stack;
}
stack = (struct mathvalue *)zalloc(STACKSZ*sizeof(struct mathvalue));
lastbase = -1;
lvals = (char **)zcalloc(LVCOUNT*sizeof(char *));
lvc = 0;
ptr = s;
sp = -1;
unary = 1;
mathparse(prek);
*ep = ptr;
if (sp)
zerr("bad math expression: unbalanced stack", NULL, 0);
for (t0 = 0; t0 != lvc; t0++)
zsfree(lvals[t0]);
ret = stack[0].val;
zfree(lvals, LVCOUNT*sizeof(char *));
zfree(stack, STACKSZ*sizeof(struct mathvalue));
if (--mlevel) {
lastbase = xlastbase;
noeval = xnoeval;
unary = xunary;
lvc = xlvc;
ptr = xptr;
yyval = xyyval;
yylval = xyylval;
lvals = xlvals;
sp = xsp;
stack = xstack;
}
return ret;
}
/**/
long
matheval(char *s)
{
char *junk;
long x;
int xmtok = mtok;
if (!*s)
return 0;
x = mathevall(s, TOPPREC, &junk);
mtok = xmtok;
if (*junk)
zerr("bad math expression: illegal character: %c", NULL, *junk);
return x;
}
/**/
long
mathevalarg(char *s, char **ss)
{
long x;
int xmtok = mtok;
x = mathevall(s, ARGPREC, ss);
if (mtok == COMMA)
(*ss)--;
mtok = xmtok;
return x;
}
/* operator-precedence parse the string and execute */
/**/
void
mathparse(int pc)
{
int q, otok, onoeval;
if (errflag)
return;
mtok = zzlex();
while (prec[mtok] <= pc) {
if (errflag)
return;
switch (mtok) {
case NUM:
push(yyval, -1);
break;
case ID:
push(getiparam(lvals[yylval]), yylval);
break;
case CID:
push(getcvar(yylval), yylval);
break;
case M_INPAR:
mathparse(TOPPREC);
if (mtok != M_OUTPAR) {
if (!errflag)
zerr("')' expected", NULL, 0);
return;
}
break;
case QUEST:
q = stack[sp].val;
if (!q)
noeval++;
mathparse(prec[QUEST] - 1);
if (!q)
noeval--;
else
noeval++;
mathparse(prec[QUEST]);
if (q)
noeval--;
op(QUEST);
continue;
default:
otok = mtok;
onoeval = noeval;
if (type[otok] == BOOL)
bop(otok);
mathparse(prec[otok] - (type[otok] != RL));
noeval = onoeval;
op(otok);
continue;
}
mtok = zzlex();
}
}
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