new expr using shunting-yard instead of recursive descent (this time with tabs)

This commit is contained in:
Evan Gates 2014-11-13 15:07:15 -08:00 committed by sin
parent 67fcc79046
commit 6240d26beb

682
expr.c
View File

@ -1,517 +1,241 @@
/* $OpenBSD: src/bin/expr/expr.c,v 1.19 2013/11/21 15:54:45 deraadt Exp $ */ #include <inttypes.h>
/* $NetBSD: expr.c,v 1.3.6.1 1996/06/04 20:41:47 cgd Exp $ */ #include <limits.h>
#include <regex.h>
/*
* Written by J.T. Conklin <jtc@netbsd.org>.
* Public domain.
*/
#include <stdio.h> #include <stdio.h>
#include <stdint.h>
#include <stdlib.h> #include <stdlib.h>
#include <string.h> #include <string.h>
#include <limits.h> #include "util.h"
#include <locale.h>
#include <ctype.h>
#include <regex.h>
#include <err.h>
static struct val *make_int(int); enum {
static struct val *make_str(char *); VAL = CHAR_MAX + 1, GE, LE, NE
static void free_value(struct val *);
static int is_integer(struct val *, int *);
static int to_integer(struct val *);
static void to_string(struct val *);
static int is_zero_or_null(struct val *);
static void nexttoken(int);
static void error(void);
static struct val *eval6(void);
static struct val *eval5(void);
static struct val *eval4(void);
static struct val *eval3(void);
static struct val *eval2(void);
static struct val *eval1(void);
static struct val *eval0(void);
enum token {
OR, AND, EQ, LT, GT, ADD, SUB, MUL, DIV, MOD, MATCH, RP, LP,
NE, LE, GE, OPERAND, EOI
}; };
struct val { typedef struct {
enum {
integer,
string
} type;
union {
char *s; char *s;
int i; intmax_t n;
} u; } Val;
};
static enum token token;
static struct val *tokval;
static char **av;
static struct val * static void doop(int*, int**, Val*, Val**);
make_int(int i) static Val match(Val, Val);
{ static void num(Val);
struct val *vp; static int valcmp(Val, Val);
static char *valstr(Val, char*);
static int yylex(void);
static int yyparse(int);
vp = (struct val *) malloc(sizeof(*vp)); static char **args;
if (vp == NULL) { static size_t intlen;
err(3, NULL); static Val yylval;
}
vp->type = integer;
vp->u.i = i;
return vp;
}
static struct val *
make_str(char *s)
{
struct val *vp;
vp = (struct val *) malloc(sizeof(*vp));
if (vp == NULL || ((vp->u.s = strdup(s)) == NULL)) {
err(3, NULL);
}
vp->type = string;
return vp;
}
// otop points to one past last op
// vtop points to one past last val
// guaranteed otop != ops
// pop two vals, pop op, apply op, push val
static void static void
free_value(struct val *vp) doop(int *ops, int **otop, Val *vals, Val **vtop)
{ {
if (vp->type == string) Val ret, a, b;
free(vp->u.s); int op;
free(vp);
}
/* determine if vp is an integer; if so, return it's value in *r */ if((*otop)[-1] == '(')
static int enprintf(2, "syntax error: extra (\n");
is_integer(struct val *vp, int *r) if(*vtop - vals < 2)
{ enprintf(2, "syntax error: missing expression or extra operator\n");
char *s;
int neg;
int i;
if (vp->type == integer) { a = (*vtop)[-2];
*r = vp->u.i; b = (*vtop)[-1];
return 1; op = (*otop)[-1];
}
/*
* POSIX.2 defines an "integer" as an optional unary minus
* followed by digits.
*/
s = vp->u.s;
i = 0;
neg = (*s == '-');
if (neg)
s++;
while (*s) {
if (!isdigit((unsigned char)*s))
return 0;
i *= 10;
i += *s - '0';
s++;
}
if (neg)
i *= -1;
*r = i;
return 1;
}
/* coerce to vp to an integer */
static int
to_integer(struct val *vp)
{
int r;
if (vp->type == integer)
return 1;
if (is_integer(vp, &r)) {
free(vp->u.s);
vp->u.i = r;
vp->type = integer;
return 1;
}
return 0;
}
/* coerce to vp to an string */
static void
to_string(struct val *vp)
{
char *tmp;
if (vp->type == string)
return;
if (asprintf(&tmp, "%d", vp->u.i) == -1)
err(3, NULL);
vp->type = string;
vp->u.s = tmp;
}
static int
is_zero_or_null(struct val *vp)
{
if (vp->type == integer) {
return (vp->u.i == 0);
} else {
return (*vp->u.s == 0 || (to_integer(vp) && vp->u.i == 0));
}
/* NOTREACHED */
}
static void
nexttoken(int pat)
{
char *p;
if ((p = *av) == NULL) {
token = EOI;
return;
}
av++;
if (pat == 0 && p[0] != '\0') {
if (p[1] == '\0') {
const char *x = "|&=<>+-*/%:()";
char *i; /* index */
if ((i = strchr(x, *p)) != NULL) {
token = i - x;
return;
}
} else if (p[1] == '=' && p[2] == '\0') {
switch (*p) {
case '<':
token = LE;
return;
case '>':
token = GE;
return;
case '!':
token = NE;
return;
}
}
}
tokval = make_str(p);
token = OPERAND;
return;
}
static void
error(void)
{
errx(2, "syntax error");
/* NOTREACHED */
}
static struct val *
eval6(void)
{
struct val *v;
if (token == OPERAND) {
nexttoken(0);
return tokval;
} else if (token == RP) {
nexttoken(0);
v = eval0();
if (token != LP) {
error();
/* NOTREACHED */
}
nexttoken(0);
return v;
} else {
error();
}
/* NOTREACHED */
return NULL;
}
/* Parse and evaluate match (regex) expressions */
static struct val *
eval5(void)
{
regex_t rp;
regmatch_t rm[2];
char errbuf[256];
int eval;
struct val *l, *r;
struct val *v;
l = eval6();
while (token == MATCH) {
nexttoken(1);
r = eval6();
/* coerce to both arguments to strings */
to_string(l);
to_string(r);
/* compile regular expression */
if ((eval = regcomp(&rp, r->u.s, 0)) != 0) {
regerror(eval, &rp, errbuf, sizeof(errbuf));
errx(2, "%s", errbuf);
}
/* compare string against pattern -- remember that patterns
are anchored to the beginning of the line */
if (regexec(&rp, l->u.s, 2, rm, 0) == 0 && rm[0].rm_so == 0) {
if (rm[1].rm_so >= 0) {
*(l->u.s + rm[1].rm_eo) = '\0';
v = make_str(l->u.s + rm[1].rm_so);
} else {
v = make_int((int)(rm[0].rm_eo - rm[0].rm_so));
}
} else {
if (rp.re_nsub == 0) {
v = make_int(0);
} else {
v = make_str("");
}
}
/* free arguments and pattern buffer */
free_value(l);
free_value(r);
regfree(&rp);
l = v;
}
return l;
}
/* Parse and evaluate multiplication and division expressions */
static struct val *
eval4(void)
{
struct val *l, *r;
enum token op;
l = eval5();
while ((op = token) == MUL || op == DIV || op == MOD) {
nexttoken(0);
r = eval5();
if (!to_integer(l) || !to_integer(r)) {
errx(2, "non-numeric argument");
}
if (op == MUL) {
l->u.i *= r->u.i;
} else {
if (r->u.i == 0) {
errx(2, "division by zero");
}
if (op == DIV) {
if (l->u.i != INT_MIN || r->u.i != -1)
l->u.i /= r->u.i;
} else {
if (l->u.i != INT_MIN || r->u.i != -1)
l->u.i %= r->u.i;
else
l->u.i = 0;
}
}
free_value(r);
}
return l;
}
/* Parse and evaluate addition and subtraction expressions */
static struct val *
eval3(void)
{
struct val *l, *r;
enum token op;
l = eval4();
while ((op = token) == ADD || op == SUB) {
nexttoken(0);
r = eval4();
if (!to_integer(l) || !to_integer(r)) {
errx(2, "non-numeric argument");
}
if (op == ADD) {
l->u.i += r->u.i;
} else {
l->u.i -= r->u.i;
}
free_value(r);
}
return l;
}
/* Parse and evaluate comparison expressions */
static struct val *
eval2(void)
{
struct val *l, *r;
enum token op;
int v = 0, li, ri;
l = eval3();
while ((op = token) == EQ || op == NE || op == LT || op == GT ||
op == LE || op == GE) {
nexttoken(0);
r = eval3();
if (is_integer(l, &li) && is_integer(r, &ri)) {
switch (op) {
case GT:
v = (li > ri);
break;
case GE:
v = (li >= ri);
break;
case LT:
v = (li < ri);
break;
case LE:
v = (li <= ri);
break;
case EQ:
v = (li == ri);
break;
case NE:
v = (li != ri);
break;
default:
break;
}
} else {
to_string(l);
to_string(r);
switch (op) { switch (op) {
case GT: case '|':
v = (strcoll(l->u.s, r->u.s) > 0); if ( a.s && *a.s) ret = (Val){ a.s , 0 };
else if(!a.s && a.n) ret = (Val){ NULL, a.n };
else if( b.s && *b.s) ret = (Val){ b.s , 0 };
else ret = (Val){ NULL, b.n };
break; break;
case GE:
v = (strcoll(l->u.s, r->u.s) >= 0); case '&':
if(((a.s && *a.s) || a.n) &&
((b.s && *b.s) || b.n)) ret = a;
else ret = (Val){ NULL, 0 };
break; break;
case LT:
v = (strcoll(l->u.s, r->u.s) < 0); case '=': ret = (Val){ NULL, valcmp(a, b) == 0 }; break;
break; case '>': ret = (Val){ NULL, valcmp(a, b) > 0 }; break;
case LE: case GE : ret = (Val){ NULL, valcmp(a, b) >= 0 }; break;
v = (strcoll(l->u.s, r->u.s) <= 0); case '<': ret = (Val){ NULL, valcmp(a, b) < 0 }; break;
break; case LE : ret = (Val){ NULL, valcmp(a, b) <= 0 }; break;
case EQ: case NE : ret = (Val){ NULL, valcmp(a, b) != 0 }; break;
v = (strcoll(l->u.s, r->u.s) == 0);
break; case '+': num(a); num(b); ret = (Val){ NULL, a.n + b.n }; break;
case NE: case '-': num(a); num(b); ret = (Val){ NULL, a.n - b.n }; break;
v = (strcoll(l->u.s, r->u.s) != 0); case '*': num(a); num(b); ret = (Val){ NULL, a.n * b.n }; break;
break; case '/': num(a); num(b); ret = (Val){ NULL, a.n / b.n }; break;
default: case '%': num(a); num(b); ret = (Val){ NULL, a.n % b.n }; break;
break;
} case ':': ret = match(a, b); break;
} }
free_value(l); (*vtop)[-2] = ret;
free_value(r); (*otop)--;
l = make_int(v); (*vtop)--;
}
return l;
} }
/* Parse and evaluate & expressions */ static Val
static struct val * match(Val vstr, Val vregx)
eval1(void)
{ {
struct val *l, *r; char b1[intlen], *str = valstr(vstr , b1);
char b2[intlen], *regx = valstr(vregx, b2);
l = eval2(); regex_t re;
while (token == AND) { regmatch_t matches[2];
nexttoken(0); char anchreg[strlen(regx) + 2];
r = eval2();
if (is_zero_or_null(l) || is_zero_or_null(r)) { sprintf(anchreg, "^%s", regx);
free_value(l);
free_value(r); if(regcomp(&re, anchreg, 0))
l = make_int(0); enprintf(3, "regcomp failed\n");
} else {
free_value(r); if(regexec(&re, str, 2, matches, 0))
return (Val){ (re.re_nsub ? "" : NULL), 0 };
if(re.re_nsub) {
intmax_t d;
char *ret, *p;
regoff_t len = matches[1].rm_eo - matches[1].rm_so + 1;
if(!(ret = malloc(len))) // FIXME: free
enprintf(3, "malloc failed\n");
d = strtoimax(ret, &p, 10);
strlcpy(ret, str + matches[1].rm_so, len);
if(*ret && !*p)
return (Val){ NULL, d };
return (Val){ ret, 0 };
} }
} return (Val){ NULL, matches[0].rm_eo - matches[0].rm_so };
return l;
} }
/* Parse and evaluate | expressions */ static void
static struct val * num(Val v)
eval0(void)
{ {
struct val *l, *r; if(v.s)
enprintf(2, "syntax error: expected integer got `%s'\n", v.s);
l = eval1();
while (token == OR) {
nexttoken(0);
r = eval1();
if (is_zero_or_null(l)) {
free_value(l);
l = r;
} else {
free_value(r);
}
}
return l;
} }
static int
valcmp(Val a, Val b)
{
char b1[intlen], *p = valstr(a, b1);
char b2[intlen], *q = valstr(b, b2);
if(!a.s && !b.s)
return (a.n > b.n) - (a.n < b.n);
return strcmp(p, q);
}
static char *
valstr(Val val, char *buf)
{
char *p = val.s;
if(!p) {
sprintf(buf, "%"PRIdMAX, val.n);
p = buf;
}
return p;
}
static int
yylex(void)
{
intmax_t d;
char *q, *p, *ops = "|&=><+-*/%():";
if(!(p = *args++))
return 0;
d = strtoimax(p, &q, 10);
if(*p && !*q) {
yylval = (Val){ NULL, d };
return VAL;
}
if(*p && !p[1] && strchr(ops, *p))
return *p;
if(strcmp(p, ">=") == 0) return GE;
if(strcmp(p, "<=") == 0) return LE;
if(strcmp(p, "!=") == 0) return NE;
yylval = (Val){ p, 0 };
return VAL;
}
static int
yyparse(int argc)
{
Val vals[argc], *vtop = vals;
int ops [argc], *otop = ops;
int type, last = 0;
char prec[] = {
['|'] = 1,
['&'] = 2,
['='] = 3, ['>'] = 3, [GE] = 3, ['<'] = 3, [LE] = 3, [NE] = 3,
['+'] = 4, ['-'] = 4,
['*'] = 5, ['/'] = 5, ['%'] = 5,
[':'] = 6,
};
while((type = yylex())) {
switch (type) {
case VAL: *vtop++ = yylval; break;
case '(': *otop++ = '(' ; break;
case ')':
if(last == '(')
enprintf(2, "syntax error: empty ( )\n");
while(otop > ops && otop[-1] != '(')
doop(ops, &otop, vals, &vtop);
if(otop == ops)
enprintf(2, "syntax error: extra )\n");
otop--;
break;
default :
if(prec[last])
enprintf(2, "syntax error: extra operator\n");
while(otop > ops && prec[otop[-1]] >= prec[type])
doop(ops, &otop, vals, &vtop);
*otop++ = type;
break;
}
last = type;
}
while(otop > ops)
doop(ops, &otop, vals, &vtop);
if(vtop == vals)
enprintf(2, "syntax error: missing expression\n");
if(vtop - vals > 1)
enprintf(2, "syntax error: extra expression\n");
vtop--;
if(vtop->s) printf("%s\n" , vtop->s);
else printf("%"PRIdMAX"\n", vtop->n);
return (vtop->s && *vtop->s) || vtop->n;
}
int int
main(int argc, char *argv[]) main(int argc, char **argv)
{ {
struct val *vp; if(!(intlen = snprintf(NULL, 0, "%"PRIdMAX, INTMAX_MIN) + 1))
enprintf(3, "failed to get max digits\n");
(void) setlocale(LC_ALL, ""); args = argv + 1;
if(*args && !strcmp("--", *args))
++args;
if (argc > 1 && !strcmp(argv[1], "--")) return !yyparse(argc);
argv++;
av = argv + 1;
nexttoken(0);
vp = eval0();
if (token != EOI) {
error();
/* NOTREACHED */
}
if (vp->type == integer)
printf("%d\n", vp->u.i);
else
printf("%s\n", vp->u.s);
exit(is_zero_or_null(vp));
} }