Data update

Task/Nested-templated-data/C/nested-templated-data.c

@@ -0,0 +1,66 @@
+#include <stdio.h>
+#include <stddef.h>
+#include <limits.h>
+
+struct ntd {
+	size_t n;
+	union {
+		size_t      x;
+		struct ntd *t;
+	} u;
+};
+#define X(X) (struct ntd){ \
+		.n = 0, \
+		{ .x = (X) }\
+	}
+#define T(...) (struct ntd){ \
+		.n = sizeof((struct ntd[]){__VA_ARGS__})/sizeof(struct ntd), \
+		{ .t = (struct ntd[]){__VA_ARGS__} }\
+	}
+
+enum { UINT_BIT = sizeof(unsigned) * CHAR_BIT };
+#define NUN(N)     (((N) + (UINT_BIT-1)) / UINT_BIT)
+#define BIT(U,X)   ((U)[(X) / UINT_BIT] & (1u << ((X) % UINT_BIT)))
+#define SET(U,X)   ((U)[(X) / UINT_BIT] |= (1u << ((X) % UINT_BIT)))
+
+static void ntd_print(struct ntd t, char const *p[], unsigned u[]) {
+	if(t.n > 0) {
+		putchar('[');
+		for(size_t i = 0; i < t.n; i++) {
+			if(i > 0) {
+				putchar(',');
+			}
+			ntd_print(t.u.t[i], p, u);
+		}
+		putchar(']');
+	} else {
+		printf("'%s'", p[t.u.x]);
+		SET(u,t.u.x);
+	}
+}
+
+int main(int argc, char **argv) {
+	struct ntd t = T(
+		T(T(X(1), X(2)),
+		  T(X(3), X(4), X(1)),
+		  X(5))
+	);
+	char const *p[] = {
+		"Payload#0",
+		"Payload#1",
+		"Payload#2",
+		"Payload#3",
+		"Payload#4",
+		"Payload#5",
+		"Payload#6",
+	};
+	unsigned u[NUN(sizeof(p)/sizeof(*p))] = { 0 };
+	ntd_print(t, p, u);
+	putchar('\n');
+	for(size_t i = 0; i < (sizeof(p)/sizeof(*p)); i++) {
+		if(!BIT(u,i)) {
+			printf("'%s' unused\n", p[i]);
+		}
+	}
+	return 0;
+}