commit 85df198b594bbffd685cd45a295cc11ebe554fda
Author: FRIGN <[email protected]>
Date: Mon Nov 17 15:39:57 2014 +0100
Refactor expr.c
Finish up what has been begun.
diff --git a/expr.c b/expr.c
index e11479e..c91f045 100644
--- a/expr.c
+++ b/expr.c
@@ -18,11 +18,12 @@ typedef struct {
intmax_t n;
} Val;
+static void enan(Val);
+static void ezero(intmax_t);
static void doop(int*, int**, Val*, Val**);
static Val match(Val, Val);
-static void num(Val);
static int valcmp(Val, Val);
-static char *valstr(Val, char*, size_t);
+static char *valstr(Val, char *, size_t);
static int lex(char *);
static int parse(char **, int);
@@ -30,49 +31,55 @@ static size_t intlen;
static Val lastval;
static void
+enan(Val v)
+{
+ if (v.s)
+ enprintf(2, "syntax error: expected integer got `%s'\n", v.s);
+}
+
+static void
ezero(intmax_t n)
{
if (n == 0)
enprintf(2, "division by zero\n");
}
-/* 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
-doop(int *ops, int **otop, Val *vals, Val **vtop)
+doop(int *op, int **opp, Val *val, Val **valp)
{
Val ret, a, b;
- int op;
+ int o;
- if ((*otop)[-1] == '(')
+ /* For an operation, we need a valid operator
+ * and two values on the stack */
+ if ((*opp)[-1] == '(')
enprintf(2, "syntax error: extra (\n");
- if (*vtop - vals < 2)
+ if (*valp - val < 2)
enprintf(2, "syntax error: missing expression or extra
operator\n");
- a = (*vtop)[-2];
- b = (*vtop)[-1];
- op = (*otop)[-1];
+ a = (*valp)[-2];
+ b = (*valp)[-1];
+ o = (*opp)[-1];
- switch (op) {
+ switch (o) {
case '|':
- if (a.s && *a.s)
+ if (a.s && *a.s) {
ret = (Val){ a.s, 0 };
- else if (!a.s && a.n)
+ } else if (!a.s && a.n) {
ret = (Val){ NULL, a.n };
- else if (b.s && *b.s)
+ } else if (b.s && *b.s) {
ret = (Val){ b.s, 0 };
- else
+ } else {
ret = (Val){ NULL, b.n };
+ }
break;
case '&':
if (((a.s && *a.s) || a.n) &&
- ((b.s && *b.s) || b.n))
+ ((b.s && *b.s) || b.n)) {
ret = a;
- else
+ } else {
ret = (Val){ NULL, 0 };
+ }
break;
case '=': ret = (Val){ NULL, valcmp(a, b) == 0 }; break;
case '>': ret = (Val){ NULL, valcmp(a, b) > 0 }; break;
@@ -81,80 +88,84 @@ doop(int *ops, int **otop, Val *vals, Val **vtop)
case LE : ret = (Val){ NULL, valcmp(a, b) <= 0 }; break;
case NE : ret = (Val){ NULL, valcmp(a, b) != 0 }; break;
- case '+': num(a); num(b); ret = (Val){ NULL, a.n + b.n }; break;
- case '-': num(a); num(b); ret = (Val){ NULL, a.n - b.n }; break;
- case '*': num(a); num(b); ret = (Val){ NULL, a.n * b.n }; break;
- case '/': num(a); num(b); ezero(b.n); ret = (Val){ NULL, a.n / b.n };
break;
- case '%': num(a); num(b); ezero(b.n); ret = (Val){ NULL, a.n % b.n };
break;
+ case '+': enan(a); enan(b); ret = (Val){ NULL, a.n + b.n }; break;
+ case '-': enan(a); enan(b); ret = (Val){ NULL, a.n - b.n }; break;
+ case '*': enan(a); enan(b); ret = (Val){ NULL, a.n * b.n }; break;
+ case '/': enan(a); enan(b); ezero(b.n); ret = (Val){ NULL, a.n / b.n };
break;
+ case '%': enan(a); enan(b); ezero(b.n); ret = (Val){ NULL, a.n % b.n };
break;
case ':': ret = match(a, b); break;
}
- (*vtop)[-2] = ret;
- (*otop)--;
- (*vtop)--;
+ (*valp)[-2] = ret;
+ (*opp)--;
+ (*valp)--;
}
static Val
match(Val vstr, Val vregx)
{
intmax_t d;
- char *ret, *p;
+ char *anchreg, *ret, *p;
+ char buf1[intlen], buf2[intlen], *str, *regx;
regoff_t len;
- char b1[intlen], *str = valstr(vstr, b1, sizeof(b1));
- char b2[intlen], *regx = valstr(vregx, b2, sizeof(b2));
-
- regex_t re;
+ regex_t re;
regmatch_t matches[2];
- char anchreg[strlen(regx) + 2];
- snprintf(anchreg, sizeof(anchreg), "^%s", regx);
+ str = valstr(vstr, buf1, sizeof(buf1));
+ regx = valstr(vregx, buf2, sizeof(buf2));
+
+ anchreg = malloc(strlen(regx) + 2);
+ if (!anchreg)
+ enprintf(3, "malloc:");
+ snprintf(anchreg, strlen(regx) + 2, "^%s", regx);
+
enregcomp(3, &re, anchreg, 0);
+ free(anchreg);
- if (regexec(&re, str, 2, matches, 0))
+ if (regexec(&re, str, 2, matches, 0)) {
+ regfree(&re);
return (Val){ (re.re_nsub ? "" : NULL), 0 };
+ }
if (re.re_nsub) {
+ regfree(&re);
len = matches[1].rm_eo - matches[1].rm_so + 1;
- ret = malloc(len); /* TODO: free ret */
+ ret = malloc(len);
if (!ret)
enprintf(3, "malloc:");
strlcpy(ret, str + matches[1].rm_so, len);
d = strtoimax(ret, &p, 10);
- if (*ret && !*p)
+ if (*ret && !*p) {
+ free(ret);
return (Val){ NULL, d };
+ }
return (Val){ ret, 0 };
}
+ regfree(&re);
return (Val){ NULL, matches[0].rm_eo - matches[0].rm_so };
}
-static void
-num(Val v)
-{
- if (v.s)
- enprintf(2, "syntax error: expected integer got `%s'\n", v.s);
-}
+
static int
valcmp(Val a, Val b)
{
- char b1[intlen], *p = valstr(a, b1, sizeof(b1));
- char b2[intlen], *q = valstr(b, b2, sizeof(b2));
+ char buf1[intlen], buf2[intlen], *astr, *bstr;
+
+ astr = valstr(a, buf1, sizeof(buf1));
+ bstr = valstr(b, buf2, sizeof(buf2));
- if (!a.s && !b.s)
- return (a.n > b.n) - (a.n < b.n);
- return strcmp(p, q);
+ return strcmp(astr, bstr);
}
static char *
valstr(Val val, char *buf, size_t bufsiz)
{
- char *p = val.s;
- if (!p) {
- snprintf(buf, bufsiz, "%"PRIdMAX, val.n);
- p = buf;
- }
- return p;
+ if (val.s)
+ return val.s;
+ snprintf(buf, bufsiz, "%"PRIdMAX, val.n);
+ return buf;
}
static int
@@ -163,22 +174,30 @@ lex(char *p)
intmax_t d;
char *q, *ops = "|&=><+-*/%():";
+ /* clean integer */
d = strtoimax(p, &q, 10);
if (*p && !*q) {
lastval = (Val){ NULL, d };
return VAL;
}
- if (*p && !p[1] && strchr(ops, *p))
+ /* one-char operand */
+ 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;
+ /* two-char operand */
+ if (*p && *(p+1) == '=' && !*(p+2)) {
+ switch (*p) {
+ case '>':
+ return GE;
+ case '<':
+ return LE;
+ case '!':
+ return NE;
+ }
+ }
+ /* nothing matched, treat as string */
lastval = (Val){ p, 0 };
return VAL;
}
