#undef	NDEBUG
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <string.h>
#include <assert.h>

#include <T1.h>

uint8_t buf1[] = {
	32 | 16,		/* [UNIVERSAL 16], constructed */
	12,	/* L */
	/* INTEGER a */
	((2 << 6) + 0),		/* [0], primitive */
	2,	/* L */
  150,
  70,
	/* b [1] EXPLICIT CHOICE */
	32 | ((2 << 6) + 1),	/* [1] */
	3,	/* L */
	((2 << 6) + 1),		/* [1] */
	1,
  'i',
	/* UTF8String c */
	((2 << 6) + 2),		/* [2], primitive */
	1,	/* L */
  'x'
};

uint8_t buf2[128];
int buf2_pos;

static int
buf2_fill(const void *buffer, size_t size, void *app_key) {

	(void)app_key;

	if(buf2_pos + size > sizeof(buf2))
		return -1;

	memcpy(buf2 + buf2_pos, buffer, size);
	buf2_pos += size;

	return 0;
}

static void
check(int is_ok, uint8_t *buf, int size, size_t consumed) {
	T1_t t, *tp;
	ber_dec_rval_t rval;
	der_enc_rval_t erval;
	int i;

	tp = memset(&t, 0, sizeof(t));

	fprintf(stderr, "Buf %p\n", buf);
	rval = ber_decode(&asn1_DEF_T1, (void **)&tp, buf, size);
	fprintf(stderr, "Returned code %d, consumed %d\n",
		(int)rval.code, (int)rval.consumed);

	if(is_ok) {
		assert(rval.code == RC_OK);
		assert(rval.consumed == (size_t)consumed);
		assert(t.a.size == 2);
		assert(t.b.present == b_PR_n);
		assert(t.b.choice.n.size == 1);
		assert(t.b.choice.n.buf[0] == 'i');
		assert(t.c.size == 1);
		assert(t.c.buf[0] == 'x');

	} else {
		if(rval.code == RC_OK) {
			assert(t.a.size != 2
				|| t.b.present != b_PR_n
				|| t.b.choice.n.size != 1
				|| t.c.size != 1
			);
		}
		assert(rval.consumed <= (size_t)consumed);
		return;
	}

	fprintf(stderr, "=> Re-creating using DER encoder <=\n");

	/*
	 * Try to re-create using DER encoding.
	 */
	buf2_pos = 0;
	erval = der_encode(&asn1_DEF_T1, tp, buf2_fill, 0);
	assert(erval.encoded != -1);
	if(erval.encoded != sizeof(buf1)) {
		printf("%d != %d\n", (int)erval.encoded, (int)sizeof(buf1));
	}
	assert(erval.encoded == sizeof(buf1));
	for(i = 0; i < (ssize_t)sizeof(buf1); i++) {
		if(buf1[i] != buf2[i]) {
			fprintf(stderr, "Recreated buffer content mismatch:\n");
			fprintf(stderr, "Byte %d, %x != %x (%d != %d)\n",
				i,
				buf1[i], buf2[i],
				buf1[i], buf2[i]
			);
		}
		assert(buf1[i] == buf2[i]);
	}

	fprintf(stderr, "=== PRINT ===\n");
	asn_fprint(stderr, &asn1_DEF_T1, tp);
	fprintf(stderr, "=== EOF ===\n");
}

static void
try_corrupt(uint8_t *buf, int size) {
	uint8_t *tmp;
	int i;

	fprintf(stderr, "\nCorrupting...\n");

	tmp = alloca(size);

	for(i = 0; i < 1000; i++) {
		int loc;
		memcpy(tmp, buf, size);

		/* Corrupt random _non-value_ location. */
		do { loc = random() % size; } while(tmp[loc] >= 70);
		do { tmp[loc] ^= random(); } while(tmp[loc] == buf[loc]);

		fprintf(stderr, "\nTry %d: corrupting byte %d (%d->%d)\n",
			i, loc, buf[loc], tmp[loc]);

		check(0, tmp, size, size);
	}
}

int
main(int ac, char **av) {

	(void)ac;	/* Unused argument */
	(void)av;	/* Unused argument */

	check(1, buf1, sizeof(buf1), sizeof(buf1));
	try_corrupt(buf1, sizeof(buf1));
	check(1, buf1, sizeof(buf1) + 10, sizeof(buf1));

	return 0;
}