#include <asn_internal.h>
#include "constraints.h"

int
asn_generic_no_constraint(asn_TYPE_descriptor_t *type_descriptor,
	const void *struct_ptr, asn_app_constraint_failed_f *cb, void *key) {

	(void)type_descriptor;	/* Unused argument */
	(void)struct_ptr;	/* Unused argument */
	(void)cb;	/* Unused argument */
	(void)key;	/* Unused argument */

	/* Nothing to check */
	return 0;
}

int
asn_generic_unknown_constraint(asn_TYPE_descriptor_t *type_descriptor,
	const void *struct_ptr, asn_app_constraint_failed_f *cb, void *key) {

	(void)type_descriptor;	/* Unused argument */
	(void)struct_ptr;	/* Unused argument */
	(void)cb;	/* Unused argument */
	(void)key;	/* Unused argument */

	/* Unknown how to check */
	return 0;
}

struct errbufDesc {
	asn_TYPE_descriptor_t *failed_type;
	const void *failed_struct_ptr;
	char *errbuf;
	size_t errlen;
};

static void
_asn_i_ctfailcb(void *key, asn_TYPE_descriptor_t *td, const void *sptr, const char *fmt, ...) {
	struct errbufDesc *arg = key;
	va_list ap;
	ssize_t vlen;
	ssize_t maxlen;

	arg->failed_type = td;
	arg->failed_struct_ptr = sptr;

	maxlen = arg->errlen;
	if(maxlen <= 0)
		return;

	va_start(ap, fmt);
	vlen = vsnprintf(arg->errbuf, maxlen, fmt, ap);
	va_end(ap);
	if(vlen >= maxlen) {
		arg->errbuf[maxlen-1] = '\0';	/* Ensuring libc correctness */
		arg->errlen = maxlen - 1;	/* Not counting termination */
		return;
	} else if(vlen >= 0) {
		arg->errbuf[vlen] = '\0';	/* Ensuring libc correctness */
		arg->errlen = vlen;		/* Not counting termination */
	} else {
		/*
		 * The libc on this system is broken.
		 */
		vlen = sizeof("<broken vsnprintf>") - 1;
		maxlen--;
		arg->errlen = vlen < maxlen ? vlen : maxlen;
		memcpy(arg->errbuf, "<broken vsnprintf>", arg->errlen);
		arg->errbuf[arg->errlen] = 0;
	}

	return;
}

int
asn_check_constraints(asn_TYPE_descriptor_t *type_descriptor,
		const void *struct_ptr, char *errbuf, size_t *errlen) {
	struct errbufDesc arg;
	int ret;

	arg.failed_type = 0;
	arg.failed_struct_ptr = 0;
	arg.errbuf = errbuf;
	arg.errlen = errlen ? *errlen : 0;

	ret = type_descriptor->check_constraints(type_descriptor,
		struct_ptr, _asn_i_ctfailcb, &arg);
	if(ret == -1 && errlen)
		*errlen = arg.errlen;

	return ret;
}