lin-epics-modules/require
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implement ?: operator

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This commit is contained in:
zimoch
2018-04-24 09:23:19 +02:00
parent 0b6d1ddde7
commit 21e4cd1b86
1 changed files with 36 additions and 16 deletions
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expr.c
+36 -16
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@@ -7,7 +7,8 @@
int exprDebug;
static int parseExpr(const char** pp, long* v, int op);
static int parseSubExpr(const char** pp, long* v, int pr, int op);
#define parseExpr(pp,v) parseSubExpr(pp, v, 0, 0)
static int parseValue(const char** pp, long* v)
{
@@ -37,7 +38,7 @@ static int parseValue(const char** pp, long* v)
{
/* handle sub-expression */
p++;
if (parseExpr(&p, &val, 0) < 0) return 0; /* no valid expression */
if (parseExpr(&p, &val) < 0) return 0; /* no valid expression */
while (isspace((unsigned char)*p)) p++;
if (*p++ != ')') return 0; /* missing ) */
}
@@ -71,7 +72,7 @@ static long ipow(long base, long exp)
}
struct {char str[4]; int pr;} ops[] = {
{"<-",0},
{"",0},
{"**",11},
{"*", 10},{"/",10},{"%",10},
{"+",9},{"-",9},
@@ -79,7 +80,8 @@ struct {char str[4]; int pr;} ops[] = {
{"<=>",7},{"<=",7},{">=",7},{"<",7},{">",7},
{"==",6},{"!=",6},
{"&&",5},{"||",5},
{"&",4},{"^",3},{"|",2},{"?",1}
{"&",4},{"^",3},{"|",2},
{"?:",1},{"?",1},{":",0}
};
static int startsWith(const char* p, const char* s)
@@ -110,27 +112,34 @@ static int parseOp(const char** pp)
return 0;
}
static int parseExpr(const char** pp, long* v, int o)
static int parseSubExpr(const char** pp, long* v, int pr, int o)
{
const char *p = *pp;
long val = *v;
long val = o ? *v : 0;
long val2;
int o2 = o;
int pr = ops[o].pr;
if (exprDebug) printf("parseExpr(%s %d): start %ld %s %s\n", ops[o].str, pr, val, ops[o].str, p);
if (exprDebug) printf("parseExpr(%d): start %ld %s %s\n", pr, val, ops[o].str, p);
do {
if (!parseValue(&p, &val2)) return -1;
if (!parseValue(&p, &val2))
{
if (exprDebug) printf("parseExpr(%d): no value after %ld %s\n", pr, val, ops[o].str);
return -1;
}
if ((o2 = parseOp(&p)))
{
if (exprDebug) printf("parseExpr(%d): %ld %s %ld %s %s\n", pr, val, ops[o].str, val2, ops[o2].str, p);
if (o && ops[o2].pr > ops[o].pr)
{
if ((o2 = parseExpr(&p, &val2, o2)) < 0) return -1;
if ((o2 = parseSubExpr(&p, &val2, ops[o].pr, o2)) < 0)
{
if (exprDebug) printf("parseExpr(%d): parse failed after %ld %s %ld\n", pr, val, ops[o].str, val2);
return -1;
}
}
}
if (exprDebug) printf("parseExpr(%d): %ld %s %ld", pr, val, ops[o].str, val2);
switch(o)
switch (o)
{
case 0: val = val2; break;
case 1: val = ipow(val, val2); break;
@@ -154,12 +163,23 @@ static int parseExpr(const char** pp, long* v, int o)
case 19: val &= val2; break;
case 20: val ^= val2; break;
case 21: val |= val2; break;
case 22: val = (val != 0); break;
case 22: if (!val) val = val2; break;
}
if (exprDebug) printf(" = %ld\n", val);
if (o2 == 23) /* ? ... : ... */
{
long val3 = 0;
val2 = 1;
if (exprDebug) printf("parseExpr(%d) if %ld ...\n", pr, val);
if ((o2 = parseSubExpr(&p, &val2, 1, 0)) == 24)
o2 = parseSubExpr(&p, &val3, 1, 0);
else o2 = 0;
if (exprDebug) printf("parseExpr(%d) if %ld then %ld else %ld\n", pr, val, val2, val3);
val = val ? val2 : val3;
}
o = o2;
} while (o && pr <= ops[o].pr);
if (exprDebug) printf("parseExpr(%d): result %ld\n", pr, val);
} while (ops[o].pr && pr <= ops[o].pr);
if (exprDebug) printf("parseExpr(%d): value = %ld return %d %s\n", pr, val, o, ops[o].str);
*pp = p;
*v = val;
return o;
@@ -219,7 +239,7 @@ size_t replaceExpressions(const char* r, char* buffer, size_t buffersize)
const char* r2 = r;
const char* f;
if (exprDebug) printf("formatted expression after '%s'\n", s);
if ((f = getFormat(&r2)) && parseExpr(&r2, &val, 0) == 0)
if ((f = getFormat(&r2)) && parseExpr(&r2, &val) == 0)
{
r = r2;
if (*s == '(' && *r2++ == ')')
@@ -231,7 +251,7 @@ size_t replaceExpressions(const char* r, char* buffer, size_t buffersize)
if (exprDebug) printf("formatted expression %s\n", s);
}
}
else if (parseExpr(&r, &val, 0) == 0)
else if (parseExpr(&r, &val) == 0)
{
/* unformatted expression */
w += sprintf(w, "%ld", val);