optional functionality for writing results to the single file and extracting specific keys from it

test_base64.c

@@ -0,0 +1,44 @@
+#include <stddef.h>
+#include <stdint.h>
+#include "types.h"
+#include "base64.h"
+#include <string.h>
+#include <assert.h>
+#include <stdio.h>
+#include <sodium/randombytes.h>
+
+struct texttestcase {
+	const char *in;
+	const char *out;
+	const char *rev;
+} tests0[] = {
+	{"", "", ""},
+	{"f", "Zg==", "f"},
+	{"fo", "Zm8=", "fo"},
+	{"foo", "Zm9v", "foo"},
+	{"foob", "Zm9vYg==", "foob"},
+	{"fooba", "Zm9vYmE=", "fooba"},
+	{"foobar", "Zm9vYmFy", "foobar"},
+};
+
+int main(void)
+{
+	char buf[1024], buf2[1024];
+	size_t r;
+	for (size_t i = 0; i < sizeof(tests0)/sizeof(tests0[0]); ++i) {
+		base64_to(buf, (const u8 *)tests0[i].in, strlen(tests0[i].in));
+		if (strcmp(buf, tests0[i].out) != 0) {
+			printf("invalid encoding result: \"%s\" -> encoded as \"%s\", but expected \"%s\".\n",
+						 tests0[i].in, buf, tests0[i].out);
+			return 1;
+		}
+		r = base64_from((u8 *)buf2, buf, strlen(buf));
+		buf2[r] = '\0';
+		if (strcmp(buf2, tests0[i].rev) != 0) {
+			printf("invalid decoding result: encoded \"%s\", decoded as \"%s\", but expected \"%s\".\n",
+						 tests0[i].out, buf2, tests0[i].rev);
+			return 2;
+		}
+	}
+	return 0;
+}