commit d49f6f2044c3a1a9d00d45f74e684cd1f44f91ae
parent 1f0f1dd320d4b37ce1c6bce49e64b7f4c797b45a
Author: FRIGN <dev@frign.de>
Date: Sun, 22 Mar 2015 14:32:56 +0100
Audit expr(1)
No bugs found, but I changed intmax_t to long long to make it more
predictable and removed some of the kitchen-sinking.
Don't return structs themselves, as this is not very elegant.
Do it like functions like stat(), which take a pointer to a
struct to fill.
Diffstat:
| M | README | | | 2 | +- |
| M | expr.c | | | 313 | +++++++++++++++++++++++++++++++++++++++---------------------------------------- |
2 files changed, 154 insertions(+), 161 deletions(-)
diff --git a/README b/README
@@ -30,7 +30,7 @@ The following tools are implemented ('*' == finished, '#' == UTF-8 support,
=*| echo yes none
=*| env yes none
#*| expand yes none
-#* expr yes none
+#*| expr yes none
=*| false yes none
= find yes none
#*| fold yes none
diff --git a/expr.c b/expr.c
@@ -1,205 +1,203 @@
/* See LICENSE file for copyright and license details. */
-#include <inttypes.h>
+#include <limits.h>
#include <stdio.h>
+#include <stdlib.h>
#include <string.h>
#include "utf.h"
#include "util.h"
-/* token types for lexing/parsing
- * single character operators represent themselves */
+/* tokens, one-character operators represent themselves */
enum {
VAL = CHAR_MAX + 1, GE, LE, NE
};
struct val {
- char *s; /* iff s is NULL, val is an integer */
- intmax_t n;
+ char *str;
+ long long num;
};
-static size_t intlen;
+static size_t maxdigits;
static void
-enan(struct val v)
+enan(struct val *v)
{
- if (v.s)
- enprintf(2, "syntax error: expected integer got `%s'\n", v.s);
+ if (!v->str)
+ return;
+ enprintf(2, "syntax error: expected integer, got %s\n", v->str);
}
static void
-ezero(intmax_t n)
+ezero(struct val *v)
{
- if (n == 0)
- enprintf(2, "division by zero\n");
-}
-
-static char *
-valstr(struct val val, char *buf, size_t bufsiz)
-{
- if (val.s)
- return val.s;
- snprintf(buf, bufsiz, "%"PRIdMAX, val.n);
- return buf;
+ if (v->num != 0)
+ return;
+ enprintf(2, "division by zero\n");
}
static int
-valcmp(struct val a, struct val b)
+valcmp(struct val *a, struct val *b)
{
- char buf1[intlen], buf2[intlen];
- char *astr = valstr(a, buf1, sizeof(buf1));
- char *bstr = valstr(b, buf2, sizeof(buf2));
+ int ret;
+ char buf[maxdigits];
+
+ if (!a->str && !b->str) {
+ ret = (a->num > b->num) - (a->num < b->num);
+ } else if (a->str && !b->str) {
+ snprintf(buf, sizeof(buf), "%lld", b->num);
+ ret = strcmp(a->str, buf);
+ } else if (!a->str && b->str) {
+ snprintf(buf, sizeof(buf), "%lld", a->num);
+ ret = strcmp(buf, b->str);
+ } else {
+ ret = strcmp(a->str, b->str);
+ }
- if (!a.s && !b.s)
- return (a.n > b.n) - (a.n < b.n);
- return strcmp(astr, bstr);
+ return ret;
}
-/* match vstr against BRE vregx (treat both values as strings)
- * if there is at least one subexpression \(...\)
- * then return the text matched by it \1 (empty string for no match)
- * else return number of characters matched (0 for no match)
- */
-static struct val
-match(struct val vstr, struct val vregx)
+static void
+match(struct val *vstr, struct val *vregx, struct val *ret)
{
regex_t re;
regmatch_t matches[2];
- intmax_t d;
- char *s, *p, buf1[intlen], buf2[intlen];
- char *str = valstr(vstr, buf1, sizeof(buf1));
- char *regx = valstr(vregx, buf2, sizeof(buf2));;
- char anchreg[strlen(regx) + 2];
-
- /* expr(1p) "all patterns are anchored to the beginning of the string" */
- snprintf(anchreg, sizeof(anchreg), "^%s", regx);
+ long long d;
+ char strbuf[maxdigits + 1], regxbuf[maxdigits + 1],
+ *s, *p, *anchreg, *str, *regx;
+ const char *errstr;
+
+ if (!vstr->str) {
+ snprintf(strbuf, sizeof(strbuf), "%lld", vstr->num);
+ str = strbuf;
+ } else {
+ str = vstr->str;
+ }
+
+ if (!vregx->str) {
+ snprintf(regxbuf, sizeof(regxbuf), "%lld", vregx->num);
+ regx = regxbuf;
+ } else {
+ regx = vregx->str;
+ }
+
+ /* anchored regex */
+ anchreg = emalloc(strlen(regx) + 2);
+ estrlcpy(anchreg, "^", sizeof(anchreg));
+ estrlcat(anchreg, regx, sizeof(anchreg));
enregcomp(3, &re, anchreg, 0);
+ free(anchreg);
if (regexec(&re, str, 2, matches, 0)) {
regfree(&re);
- return (struct val){ (re.re_nsub ? "" : NULL), 0 };
- }
-
- if (re.re_nsub) {
+ ret->str = re.re_nsub ? "" : NULL;
+ return;
+ } else if (re.re_nsub) {
regfree(&re);
+
s = str + matches[1].rm_so;
p = str + matches[1].rm_eo;
-
*p = '\0';
- d = strtoimax(s, &p, 10);
- if (*s && !*p) /* string matched by subexpression is an integer */
- return (struct val){ NULL, d };
- /* FIXME? string is never free()d, worth fixing?
- * need to allocate as it could be in buf1 instead of vstr.s */
- return (struct val){ enstrdup(3, s), 0 };
+ d = strtonum(s, LLONG_MIN, LLONG_MAX, &errstr);
+ if (!errstr) {
+ ret->num = d;
+ return;
+ } else {
+ ret->str = enstrdup(3, s);
+ return;
+ }
+ } else {
+ regfree(&re);
+ str += matches[0].rm_so;
+ ret->num = utfnlen(str, matches[0].rm_eo - matches[0].rm_so);
+ return;
}
- regfree(&re);
- str += matches[0].rm_so;
- return (struct val){ NULL, utfnlen(str, matches[0].rm_eo - matches[0].rm_so) };
}
-/* ops points to a stack of operators, opp points to one past the last op
- * vals points to a stack of values , valp points to one past the last val
- * guaranteed that opp != ops
- * ops is unused here, but still included for parity with vals
- * pop operator, pop two values, apply operator, push result
- */
static void
-doop(int *ops, int **opp, struct val *vals, struct val **valp)
+doop(int *ophead, int *opp, struct val *valhead, struct val *valp)
{
- struct val ret, a, b;
+ struct val ret = { .str = NULL, .num = 0 }, *a, *b;
int op;
- /* For an operation, we need a valid operator
- * and two values on the stack */
- if ((*opp)[-1] == '(')
+ /* an operation "a op b" needs an operator and two values */
+ if (opp[-1] == '(')
enprintf(2, "syntax error: extra (\n");
- if (*valp - vals < 2)
+ if (valp - valhead < 2)
enprintf(2, "syntax error: missing expression or extra operator\n");
- a = (*valp)[-2];
- b = (*valp)[-1];
- op = (*opp)[-1];
+ a = valp - 2;
+ b = valp - 1;
+ op = opp[-1];
switch (op) {
case '|':
- if ( a.s && *a.s) ret = (struct val){ a.s , 0 };
- else if (!a.s && a.n) ret = (struct val){ NULL, a.n };
- else if ( b.s && *b.s) ret = (struct val){ b.s , 0 };
- else ret = (struct val){ NULL, b.n };
+ if ( a->str && *a->str) ret.str = a->str;
+ else if (!a->str && a->num) ret.num = a->num;
+ else if ( b->str && *b->str) ret.str = b->str;
+ else ret.num = b->num;
break;
case '&':
- if (((a.s && *a.s) || a.n) && ((b.s && *b.s) || b.n))
- ret = a;
- else
- ret = (struct val){ NULL, 0 };
+ if (((a->str && *a->str) || a->num) &&
+ ((b->str && *b->str) || b->num)) {
+ ret.str = a->str;
+ ret.num = a->num;
+ }
break;
- case '=': ret = (struct val){ NULL, valcmp(a, b) == 0 }; break;
- case '>': ret = (struct val){ NULL, valcmp(a, b) > 0 }; break;
- case GE : ret = (struct val){ NULL, valcmp(a, b) >= 0 }; break;
- case '<': ret = (struct val){ NULL, valcmp(a, b) < 0 }; break;
- case LE : ret = (struct val){ NULL, valcmp(a, b) <= 0 }; break;
- case NE : ret = (struct val){ NULL, valcmp(a, b) != 0 }; break;
+ case '=': ret.num = (valcmp(a, b) == 0); break;
+ case '>': ret.num = (valcmp(a, b) > 0); break;
+ case GE : ret.num = (valcmp(a, b) >= 0); break;
+ case '<': ret.num = (valcmp(a, b) < 0); break;
+ case LE : ret.num = (valcmp(a, b) <= 0); break;
+ case NE : ret.num = (valcmp(a, b) != 0); break;
- case '+': enan(a); enan(b); ret = (struct val){ NULL, a.n + b.n }; break;
- case '-': enan(a); enan(b); ret = (struct val){ NULL, a.n - b.n }; break;
- case '*': enan(a); enan(b); ret = (struct val){ NULL, a.n * b.n }; break;
- case '/': enan(a); enan(b); ezero(b.n); ret = (struct val){ NULL, a.n / b.n }; break;
- case '%': enan(a); enan(b); ezero(b.n); ret = (struct val){ NULL, a.n % b.n }; break;
+ case '+': enan(a); enan(b); ret.num = a->num + b->num; break;
+ case '-': enan(a); enan(b); ret.num = a->num - b->num; break;
+ case '*': enan(a); enan(b); ret.num = a->num * b->num; break;
+ case '/': enan(a); enan(b); ezero(b); ret.num = a->num / b->num; break;
+ case '%': enan(a); enan(b); ezero(b); ret.num = a->num % b->num; break;
- case ':': ret = match(a, b); break;
+ case ':': match(a, b, &ret); break;
}
- (*valp)[-2] = ret;
- (*opp)--;
- (*valp)--;
+ valp[-2] = ret;
}
-/* retrn the type of the next token, s
- * if it is a value, place the value in v for use by parser
- */
static int
lex(char *s, struct val *v)
{
- intmax_t d;
- char *p, *ops = "|&=><+-*/%():";
-
- /* clean integer */
- d = strtoimax(s, &p, 10);
- if (*s && !*p) {
- *v = (struct val){ NULL, d };
- return VAL;
+ long long d;
+ int type = VAL;
+ char *ops = "|&=><+-*/%():";
+ const char *errstr;
+
+ d = strtonum(s, LLONG_MIN, LLONG_MAX, &errstr);
+
+ if (!errstr) {
+ /* integer */
+ v->num = d;
+ } else if (s[0] && strchr(ops, s[0]) && !s[1]) {
+ /* one-char operand */
+ type = s[0];
+ } else if (s[0] && strchr("><!", s[0]) && s[1] == '=' && !s[2]) {
+ /* two-char operand */
+ type = (s[0] == '>') ? GE : (s[0] == '<') ? LE : NE;
+ } else {
+ /* string */
+ v->str = s;
}
- /* one-char operand */
- if (*s && !s[1] && strchr(ops, *s))
- return *s;
-
- /* two-char operand */
- if (!strcmp(s, ">=")) return GE;
- if (!strcmp(s, "<=")) return LE;
- if (!strcmp(s, "!=")) return NE;
-
- /* nothing matched, treat as string */
- *v = (struct val){ s, 0 };
- return VAL;
+ return type;
}
-/* using shunting-yard to convert from infix to rpn
- * https://en.wikipedia.org/wiki/Shunting-yard_algorithm
- * instead of creating rpn output to evaluate later, evaluate it immediately as
- * it is created
- * vals is the value stack, valp points to one past last value on the stack
- * ops is the operator stack, opp points to one past last op on the stack
- */
static int
-parse(char *expr[], int exprlen)
+parse(char *expr[], int numexpr)
{
- struct val vals[exprlen], *valp = vals, v;
- int ops[exprlen], *opp = ops;
- int i, type, lasttype = 0;
- char prec[] = { /* precedence of operators */
+ struct val valhead[numexpr], *valp = valhead, v = { .str = NULL, .num = 0 };
+ int ophead[numexpr], *opp = ophead, type, lasttype = 0;
+ char prec[] = {
+ [ 0 ] = 0, [VAL] = 0, ['('] = 0, [')'] = 0,
['|'] = 1,
['&'] = 2,
['='] = 3, ['>'] = 3, [GE] = 3, ['<'] = 3, [LE] = 3, [NE] = 3,
@@ -208,70 +206,65 @@ parse(char *expr[], int exprlen)
[':'] = 6,
};
- for (i = 0; i < exprlen; i++) {
- switch ((type = lex(expr[i], &v))) {
+ for (; *expr; expr++) {
+ switch ((type = lex(*expr, &v))) {
case VAL:
- *valp++ = v;
+ (*valp).str = v.str;
+ (*valp).num = v.num;
+ valp++;
break;
case '(':
- *opp++ = '(';
+ *opp++ = type;
break;
case ')':
if (lasttype == '(')
enprintf(2, "syntax error: empty ( )\n");
- while (opp > ops && opp[-1] != '(')
- doop(ops, &opp, vals, &valp);
- if (opp == ops)
+ while (opp > ophead && opp[-1] != '(')
+ doop(ophead, opp--, valhead, valp--);
+ if (opp == ophead)
enprintf(2, "syntax error: extra )\n");
opp--;
break;
default: /* operator */
if (prec[lasttype])
enprintf(2, "syntax error: extra operator\n");
- while (opp > ops && prec[opp[-1]] >= prec[type])
- doop(ops, &opp, vals, &valp);
+ while (opp > ophead && prec[opp[-1]] >= prec[type])
+ doop(ophead, opp--, valhead, valp--);
*opp++ = type;
break;
}
lasttype = type;
+ v.str = NULL;
+ v.num = 0;
}
- while (opp > ops)
- doop(ops, &opp, vals, &valp);
-
- if (valp == vals)
+ while (opp > ophead)
+ doop(ophead, opp--, valhead, valp--);
+ if (valp == valhead)
enprintf(2, "syntax error: missing expression\n");
- if (--valp != vals)
+ if (--valp > valhead)
enprintf(2, "syntax error: extra expression\n");
- if (valp->s)
- printf("%s\n", valp->s);
+ if (valp->str)
+ puts(valp->str);
else
- printf("%"PRIdMAX"\n", valp->n);
+ printf("%lld\n", valp->num);
- return (valp->s && *valp->s) || valp->n;
+ return (valp->str && *valp->str) || valp->num;
}
-/* the only way to get usage() is if the user didn't supply -- and expression
- * begins with a -
- * expr(1p): "... the conforming application must employ the -- construct ...
- * if there is any chance the first operand might be a negative integer (or any
- * string with a leading minus"
- */
static void
usage(void)
{
- enprintf(3, "usage: %s [--] expression\n"
- "note : the -- is mandatory if expression begins with a -\n", argv0);
+ enprintf(3, "usage: %s expression\n", argv0);
}
int
main(int argc, char *argv[])
{
- intmax_t n = INTMAX_MIN;
+ long long n = LLONG_MIN;
- /* Get the maximum number of digits (+ sign) */
- for (intlen = (n < 0); n; n /= 10, ++intlen)
- ;
+ /* maximum number of digits + sign */
+ for (maxdigits = (n < 0); n; n /= 10, ++maxdigits);
ARGBEGIN {
default:
