expr: improvements
- handle divide by zero. - use eregcomp(). - use emalloc(). - use snprintf() for safety and add a buffer size argument to valstr() just to be sure. - code-style fixes.
This commit is contained in:
Hiltjo Posthuma
sin
parent
1822f70d12
commit
b3ae1a7b4b
81
expr.c
81
expr.c
@ -2,10 +2,11 @@
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#include <inttypes.h>
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#include <limits.h>
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#include <regex.h>
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#include <stdio.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "util.h"
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enum {
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@ -21,7 +22,7 @@ static void doop(int*, int**, Val*, Val**);
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static Val match(Val, Val);
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static void num(Val);
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static int valcmp(Val, Val);
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static char *valstr(Val, char*);
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static char *valstr(Val, char*, size_t);
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static int yylex(void);
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static int yyparse(int);
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@ -29,6 +30,13 @@ static char **args;
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static size_t intlen;
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static Val yylval;
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static void
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ezero(intmax_t n)
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{
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if(n == 0)
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enprintf(2, "division by zero\n");
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}
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/* otop points to one past last op
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* vtop points to one past last val
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* guaranteed otop != ops
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@ -51,18 +59,22 @@ doop(int *ops, int **otop, Val *vals, Val **vtop)
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switch (op) {
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case '|':
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if ( a.s && *a.s) ret = (Val){ a.s , 0 };
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else if(!a.s && a.n) ret = (Val){ NULL, a.n };
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else if( b.s && *b.s) ret = (Val){ b.s , 0 };
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else ret = (Val){ NULL, b.n };
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if (a.s && *a.s)
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ret = (Val){ a.s, 0 };
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else if (!a.s && a.n)
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ret = (Val){ NULL, a.n };
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else if (b.s && *b.s)
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ret = (Val){ b.s, 0 };
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else
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ret = (Val){ NULL, b.n };
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break;
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case '&':
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if (((a.s && *a.s) || a.n) &&
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((b.s && *b.s) || b.n)) ret = a;
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else ret = (Val){ NULL, 0 };
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((b.s && *b.s) || b.n))
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ret = a;
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else
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ret = (Val){ NULL, 0 };
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break;
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case '=': ret = (Val){ NULL, valcmp(a, b) == 0 }; break;
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case '>': ret = (Val){ NULL, valcmp(a, b) > 0 }; break;
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case GE : ret = (Val){ NULL, valcmp(a, b) >= 0 }; break;
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@ -73,8 +85,8 @@ doop(int *ops, int **otop, Val *vals, Val **vtop)
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case '+': num(a); num(b); ret = (Val){ NULL, a.n + b.n }; break;
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case '-': num(a); num(b); ret = (Val){ NULL, a.n - b.n }; break;
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case '*': num(a); num(b); ret = (Val){ NULL, a.n * b.n }; break;
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case '/': num(a); num(b); ret = (Val){ NULL, a.n / b.n }; break;
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case '%': num(a); num(b); ret = (Val){ NULL, a.n % b.n }; break;
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case '/': num(a); num(b); ezero(b.n); ret = (Val){ NULL, a.n / b.n }; break;
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case '%': num(a); num(b); ezero(b.n); ret = (Val){ NULL, a.n % b.n }; break;
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case ':': ret = match(a, b); break;
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}
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@ -87,29 +99,25 @@ doop(int *ops, int **otop, Val *vals, Val **vtop)
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static Val
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match(Val vstr, Val vregx)
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{
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char b1[intlen], *str = valstr(vstr , b1);
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char b2[intlen], *regx = valstr(vregx, b2);
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intmax_t d;
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char *ret, *p;
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regoff_t len;
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char b1[intlen], *str = valstr(vstr, b1, sizeof(b1));
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char b2[intlen], *regx = valstr(vregx, b2, sizeof(b2));
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regex_t re;
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regmatch_t matches[2];
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char anchreg[strlen(regx) + 2];
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sprintf(anchreg, "^%s", regx);
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if(regcomp(&re, anchreg, 0))
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enprintf(3, "regcomp failed\n");
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snprintf(anchreg, sizeof(anchreg), "^%s", regx);
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enregcomp(3, &re, anchreg, 0);
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if (regexec(&re, str, 2, matches, 0))
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return (Val){ (re.re_nsub ? "" : NULL), 0 };
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if (re.re_nsub) {
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intmax_t d;
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char *ret, *p;
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regoff_t len = matches[1].rm_eo - matches[1].rm_so + 1;
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if(!(ret = malloc(len))) // FIXME: free
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enprintf(3, "malloc failed\n");
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len = matches[1].rm_eo - matches[1].rm_so + 1;
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ret = emalloc(len); /* TODO: free ret */
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d = strtoimax(ret, &p, 10);
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strlcpy(ret, str + matches[1].rm_so, len);
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@ -130,8 +138,8 @@ num(Val v)
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static int
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valcmp(Val a, Val b)
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{
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char b1[intlen], *p = valstr(a, b1);
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char b2[intlen], *q = valstr(b, b2);
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char b1[intlen], *p = valstr(a, b1, sizeof(b1));
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char b2[intlen], *q = valstr(b, b2, sizeof(b2));
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if (!a.s && !b.s)
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return (a.n > b.n) - (a.n < b.n);
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@ -139,11 +147,11 @@ valcmp(Val a, Val b)
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}
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static char *
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valstr(Val val, char *buf)
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valstr(Val val, char *buf, size_t bufsiz)
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{
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char *p = val.s;
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if (!p) {
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sprintf(buf, "%"PRIdMAX, val.n);
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snprintf(buf, bufsiz, "%"PRIdMAX, val.n);
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p = buf;
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}
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return p;
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@ -167,9 +175,12 @@ yylex(void)
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if (*p && !p[1] && strchr(ops, *p))
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return *p;
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if(strcmp(p, ">=") == 0) return GE;
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if(strcmp(p, "<=") == 0) return LE;
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if(strcmp(p, "!=") == 0) return NE;
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if (strcmp(p, ">=") == 0)
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return GE;
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if (strcmp(p, "<=") == 0)
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return LE;
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if (strcmp(p, "!=") == 0)
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return NE;
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yylval = (Val){ p, 0 };
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return VAL;
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@ -222,8 +233,10 @@ yyparse(int argc)
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enprintf(2, "syntax error: extra expression\n");
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vtop--;
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if(vtop->s) printf("%s\n" , vtop->s);
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else printf("%"PRIdMAX"\n", vtop->n);
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if (vtop->s)
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printf("%s\n", vtop->s);
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else
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printf("%"PRIdMAX"\n", vtop->n);
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return (vtop->s && *vtop->s) || vtop->n;
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}
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