add validation code

Signed-off-by: John Crispin <blogic@openwrt.org>

3 files changed, 1049 insertions, 0 deletions

diff --git a/validate/cli.c b/validate/cli.c
new file mode 100644
index 0000000..dc5e96b
--- /dev/null
+++ b/validate/cli.c
@@ -0,0 +1,28 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdbool.h>
+#include <ctype.h>
+
+#include <arpa/inet.h>
+#include <netinet/ether.h>
+#include <sys/stat.h>
+
+#include "libvalidate.h"
+
+int main(int argc, char **argv)
+{
+	bool rv;
+
+	if (argc == 3) {
+		rv = dt_parse(argv[1], argv[2]);
+
+		printf("%s - %s = %s\n", argv[1], argv[2], rv ? "true" : "false");
+
+		return rv ? 0 : 1;
+	} else if (argc > 3) {
+
+	}
+
+	return 0;
+}
diff --git a/validate/libvalidate.h b/validate/libvalidate.h
new file mode 100644
index 0000000..d3b8e05
--- /dev/null
+++ b/validate/libvalidate.h
@@ -0,0 +1,6 @@
+#ifndef _VALIDATE_H__
+#define _VALIDATE_H__
+
+bool dt_parse(const char *code, const char *value);
+
+#endif
diff --git a/validate/validate.c b/validate/validate.c
new file mode 100644
index 0000000..c3ae56e
--- /dev/null
+++ b/validate/validate.c
@@ -0,0 +1,1015 @@
+/*
+ * Copyright (C) 2013 Jo-Philipp Wich <jow@openwrt.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License version 2.1
+ * as published by the Free Software Foundation
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdbool.h>
+#include <ctype.h>
+
+#include <arpa/inet.h>
+#include <netinet/ether.h>
+#include <sys/stat.h>
+
+#include "libvalidate.h"
+
+enum dt_optype {
+	OP_UNKNOWN,
+	OP_BOOL,
+	OP_NUMBER,
+	OP_STRING,
+	OP_FUNCTION
+};
+
+struct dt_fun;
+
+struct dt_op {
+	enum dt_optype type;
+	const char *next;
+	int length;
+	int nextop;
+	union {
+		bool boolean;
+		double number;
+		const char *string;
+		struct dt_fun *function;
+	} value;
+};
+
+struct dt_state {
+	int pos;
+	int depth;
+	const char *value;
+	struct dt_op stack[32];
+};
+
+struct dt_fun {
+	const char *name;
+	bool (*call)(struct dt_state *s, int nargs);
+};
+
+static bool
+dt_test_number(double number, const char *value)
+{
+	char *e;
+	double n;
+
+	n = strtod(value, &e);
+
+	return (e > value && *e == 0 && n == number);
+}
+
+static bool
+dt_test_string(const char *s, const char *end, const char *value)
+{
+	bool esc = false;
+
+	while (*value)
+	{
+		if (s > end)
+			return false;
+
+		if (!esc && *s == '\\')
+		{
+			s++;
+
+			if (s >= end)
+				break;
+
+			esc = true;
+			continue;
+		}
+
+		if (*s != *value)
+			return false;
+
+		esc = false;
+		value++;
+		s++;
+	}
+
+	return (*s == *value || (s > end && *value == 0));
+}
+
+static bool
+dt_step(struct dt_state *s);
+
+static bool
+dt_call(struct dt_state *s);
+
+static bool
+dt_type_or(struct dt_state *s, int nargs)
+{
+	while (nargs--)
+		if (dt_step(s))
+			return true;
+
+	return false;
+}
+
+static bool
+dt_type_and(struct dt_state *s, int nargs)
+{
+	while (nargs--)
+		if (!dt_step(s))
+			return false;
+
+	return true;
+}
+
+static bool
+dt_type_not(struct dt_state *s, int nargs)
+{
+	if (!nargs)
+		return false;
+
+	return !dt_step(s);
+}
+
+static bool
+dt_type_neg(struct dt_state *s, int nargs)
+{
+	bool rv;
+	const char *value = s->value;
+
+	if (!nargs)
+		return false;
+
+	if (*s->value == '!')
+		while (isspace(*++s->value));
+
+	rv = dt_step(s);
+	s->value = value;
+
+	return rv;
+}
+
+static bool
+dt_type_list(struct dt_state *s, int nargs)
+{
+	bool rv = true;
+	int pos = s->pos;
+	char *p, *str = strdup(s->value);
+	const char *value = s->value;
+
+	if (!str || !nargs)
+		return false;
+
+	for (p = strtok(str, " \t"); p; p = strtok(NULL, " \t"))
+	{
+		s->value = p;
+
+		if (!dt_step(s))
+		{
+			rv = false;
+			break;
+		}
+
+		s->pos = pos;
+	}
+
+	s->value = value;
+	free(str);
+
+	return rv;
+}
+
+static bool
+dt_type_min(struct dt_state *s, int nargs)
+{
+	int n;
+	char *e;
+
+	if (nargs >= 1 && s->stack[s->pos].type == OP_NUMBER)
+	{
+		n = strtol(s->value, &e, 0);
+
+		return (e > s->value && *e == 0 &&
+		        n >= s->stack[s->pos].value.number);
+	}
+
+	return false;
+}
+
+static bool
+dt_type_max(struct dt_state *s, int nargs)
+{
+	int n;
+	char *e;
+
+	if (nargs >= 1 && s->stack[s->pos].type == OP_NUMBER)
+	{
+		n = strtol(s->value, &e, 0);
+
+		return (e > s->value && *e == 0 &&
+		        n <= s->stack[s->pos].value.number);
+	}
+
+	return false;
+}
+
+static bool
+dt_type_range(struct dt_state *s, int nargs)
+{
+	int n;
+	char *e;
+
+	if (nargs >= 2 &&
+	    s->stack[s->pos].type == OP_NUMBER &&
+	    s->stack[s->pos + 1].type == OP_NUMBER)
+	{
+		n = strtol(s->value, &e, 0);
+
+		return (e > s->value && *e == 0 &&
+		        n >= s->stack[s->pos].value.number &&
+		        n <= s->stack[s->pos + 1].value.number);
+	}
+
+	return false;
+}
+
+static bool
+dt_type_minlen(struct dt_state *s, int nargs)
+{
+	if (nargs >= 1 && s->stack[s->pos].type == OP_NUMBER)
+		return (strlen(s->value) >= s->stack[s->pos].value.number);
+
+	return false;
+}
+
+static bool
+dt_type_maxlen(struct dt_state *s, int nargs)
+{
+	if (nargs >= 1 && s->stack[s->pos].type == OP_NUMBER)
+		return (strlen(s->value) <= s->stack[s->pos].value.number);
+
+	return false;
+}
+
+static bool
+dt_type_rangelen(struct dt_state *s, int nargs)
+{
+	if (nargs >= 2 &&
+	    s->stack[s->pos].type == OP_NUMBER &&
+	    s->stack[s->pos + 1].type == OP_NUMBER)
+		return (strlen(s->value) >= s->stack[s->pos].value.number &&
+				strlen(s->value) <= s->stack[s->pos + 1].value.number);
+
+	return false;
+}
+
+static bool
+dt_type_int(struct dt_state *s, int nargs)
+{
+	char *e;
+
+	strtol(s->value, &e, 0);
+
+	return (e > s->value && *e == 0);
+}
+
+static bool
+dt_type_uint(struct dt_state *s, int nargs)
+{
+	int n;
+	char *e;
+
+	n = strtol(s->value, &e, 0);
+
+	return (e > s->value && *e == 0 && n >= 0);
+}
+
+static bool
+dt_type_float(struct dt_state *s, int nargs)
+{
+	char *e;
+
+	strtod(s->value, &e);
+
+	return (e > s->value && *e == 0);
+}
+
+static bool
+dt_type_ufloat(struct dt_state *s, int nargs)
+{
+	int n;
+	char *e;
+
+	n = strtod(s->value, &e);
+
+	return (e > s->value && *e == 0 && n >= 0.0);
+}
+
+static bool
+dt_type_bool(struct dt_state *s, int nargs)
+{
+	int i;
+	const char *values[] = {
+		"0", "off", "false", "no",
+		"1", "on", "true", "yes"
+	};
+
+	for (i = 0; i < sizeof(values) / sizeof(values[0]); i++)
+		if (!strcasecmp(values[i], s->value))
+			return true;
+
+	return false;
+}
+
+static bool
+dt_type_string(struct dt_state *s, int nargs)
+{
+	return true;
+}
+
+static bool
+dt_type_ip4addr(struct dt_state *s, int nargs)
+{
+	struct in6_addr a;
+	return inet_pton(AF_INET, s->value, &a);
+}
+
+static bool
+dt_type_ip6addr(struct dt_state *s, int nargs)
+{
+	struct in6_addr a;
+	return inet_pton(AF_INET6, s->value, &a);
+}
+
+static bool
+dt_type_ipaddr(struct dt_state *s, int nargs)
+{
+	return (dt_type_ip4addr(s, 0) || dt_type_ip6addr(s, 0));
+}
+
+static bool
+dt_type_netmask4(struct dt_state *s, int nargs)
+{
+	int i;
+	struct in_addr a;
+
+	if (!inet_pton(AF_INET, s->value, &a))
+		return false;
+
+	if (a.s_addr == 0)
+		return true;
+
+	a.s_addr = ntohl(a.s_addr);
+
+	for (i = 0; (i < 32) && !(a.s_addr & (1 << i)); i++);
+
+	return ((uint32_t)(~((1 << i) - 1)) == a.s_addr);
+}
+
+static bool
+dt_type_netmask6(struct dt_state *s, int nargs)
+{
+	int i;
+	struct in6_addr a;
+
+	if (!inet_pton(AF_INET6, s->value, &a))
+		return false;
+
+	for (i = 0; (i < 16) && (a.s6_addr[i] == 0xFF); i++);
+
+	if (i == 16)
+		return true;
+
+	if ((a.s6_addr[i] != 255) && (a.s6_addr[i] != 254) &&
+		(a.s6_addr[i] != 252) && (a.s6_addr[i] != 248) &&
+		(a.s6_addr[i] != 240) && (a.s6_addr[i] != 224) &&
+		(a.s6_addr[i] != 192) && (a.s6_addr[i] != 128) &&
+		(a.s6_addr[i] != 0))
+		return false;
+
+	for (; (i < 16) && (a.s6_addr[i] == 0); i++);
+
+	return (i == 16);
+}
+
+static bool
+dt_type_cidr4(struct dt_state *s, int nargs)
+{
+	int n;
+	struct in_addr a;
+	char *p, buf[sizeof("255.255.255.255/32\0")];
+
+	if (strlen(s->value) >= sizeof(buf))
+		return false;
+
+	strcpy(buf, s->value);
+	p = strchr(buf, '/');
+
+	if (p)
+	{
+		*p++ = 0;
+
+		n = strtoul(p, &p, 10);
+
+		if ((*p != 0) || (n > 32))
+			return false;
+	}
+
+	return inet_pton(AF_INET, buf, &a);
+}
+
+static bool
+dt_type_cidr6(struct dt_state *s, int nargs)
+{
+	int n;
+	struct in6_addr a;
+	char *p, buf[sizeof("FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:255.255.255.255/128\0")];
+
+	if (strlen(s->value) >= sizeof(buf))
+		return false;
+
+	strcpy(buf, s->value);
+	p = strchr(buf, '/');
+
+	if (p)
+	{
+		*p++ = 0;
+
+		n = strtoul(p, &p, 10);
+
+		if ((*p != 0) || (n > 128))
+			return false;
+	}
+
+	return inet_pton(AF_INET6, buf, &a);
+}
+
+static bool
+dt_type_cidr(struct dt_state *s, int nargs)
+{
+	return (dt_type_cidr4(s, 0) || dt_type_cidr6(s, 0));
+}
+
+static bool
+dt_type_ipmask4(struct dt_state *s, int nargs)
+{
+	bool rv;
+	struct in_addr a;
+	const char *value;
+	char *p, buf[sizeof("255.255.255.255/255.255.255.255\0")];
+
+	if (strlen(s->value) >= sizeof(buf))
+		return false;
+
+	strcpy(buf, s->value);
+	p = strchr(buf, '/');
+
+	if (p)
+	{
+		*p++ = 0;
+
+		value = s->value;
+		s->value = p;
+		rv = dt_type_netmask4(s, 0);
+		s->value = value;
+
+		if (!rv)
+			return false;
+	}
+
+	return inet_pton(AF_INET, buf, &a);
+}
+
+static bool
+dt_type_ipmask6(struct dt_state *s, int nargs)
+{
+	bool rv;
+	struct in6_addr a;
+	const char *value;
+	char *p, buf[sizeof("FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:255.255.255.255/"
+	                    "FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:255.255.255.255\0")];
+
+	if (strlen(s->value) >= sizeof(buf))
+		return false;
+
+	strcpy(buf, s->value);
+	p = strchr(buf, '/');
+
+	if (p)
+	{
+		*p++ = 0;
+
+		value = s->value;
+		s->value = p;
+		rv = dt_type_netmask6(s, 0);
+		s->value = value;
+
+		if (!rv)
+			return false;
+	}
+
+	return inet_pton(AF_INET6, buf, &a);
+}
+
+static bool
+dt_type_ipmask(struct dt_state *s, int nargs)
+{
+	return (dt_type_ipmask4(s, 0) || dt_type_ipmask6(s, 0));
+}
+
+static bool
+dt_type_port(struct dt_state *s, int nargs)
+{
+	int n;
+	char *e;
+
+	n = strtoul(s->value, &e, 10);
+
+	return (e > s->value && *e == 0 && n <= 65535);
+}
+
+static bool
+dt_type_portrange(struct dt_state *s, int nargs)
+{
+	int n, m;
+	char *e;
+
+	n = strtoul(s->value, &e, 10);
+
+	if (e == s->value || *e != '-')
+		return false;
+
+	m = strtoul(e + 1, &e, 10);
+
+	return (*e == 0 && n <= 65535 && m <= 65535 && n <= m);
+}
+
+static bool
+dt_type_macaddr(struct dt_state *s, int nargs)
+{
+	return !!ether_aton(s->value);
+}
+
+static bool
+dt_type_uciname(struct dt_state *s, int nargs)
+{
+	const char *p;
+
+	for (p = s->value;
+	     *p && ((*p >= 'A' && *p <= 'Z') || (*p >= 'a' && *p <= 'z') ||
+	            (*p >= '0' && *p <= '9') || (*p == '_'));
+		 p++);
+
+	return (*p == 0);
+}
+
+static bool
+dt_type_wpakey(struct dt_state *s, int nargs)
+{
+	int len = strlen(s->value);
+	const char *p = s->value;
+
+	if (len == 64)
+	{
+		while (isxdigit(*p))
+			p++;
+
+		return (*p == 0);
+	}
+
+	return (len >= 8 && len <= 63);
+}
+
+static bool
+dt_type_wepkey(struct dt_state *s, int nargs)
+{
+	int len = strlen(s->value);
+	const char *p = s->value;
+
+	if (!strncmp(p, "s:", 2))
+	{
+		len -= 2;
+		p += 2;
+	}
+
+	if (len == 10 || len == 26)
+	{
+		while (isxdigit(*p))
+			p++;
+
+		return (*p == 0);
+	}
+
+	return (len == 5 || len == 13);
+}
+
+static bool
+dt_type_hostname(struct dt_state *s, int nargs)
+{
+	const char *p, *last;
+
+	for (p = last = s->value; *p; p++)
+	{
+		if (*p == '.')
+		{
+			if ((p - last) == 0 || (p - last) > 63)
+				return false;
+
+			last = p + 1;
+			continue;
+		}
+		else if ((*p >= 'A' && *p <= 'Z') || (*p >= 'a' && *p <= 'z') ||
+		         (*p >= '0' && *p <= '9') || (*p == '_') || (*p == '-'))
+		{
+			continue;
+		}
+
+		return false;
+	}
+
+	return ((p - last) > 0 && (p - last) <= 255);
+}
+
+static bool
+dt_type_host(struct dt_state *s, int nargs)
+{
+	return (dt_type_hostname(s, 0) || dt_type_ipaddr(s, 0));
+}
+
+static bool
+dt_type_network(struct dt_state *s, int nargs)
+{
+	return (dt_type_uciname(s, 0) || dt_type_host(s, 0));
+}
+
+static bool
+dt_type_phonedigit(struct dt_state *s, int nargs)
+{
+	const char *p;
+
+	for (p = s->value;
+	     *p && ((*p >= '0' && *p <= '9') || (*p == '*') || (*p == '#') ||
+	            (*p == '!') || (*p == '.'));
+		 p++);
+
+	return (*p == 0);
+}
+
+static bool
+dt_type_directory(struct dt_state *s, int nargs)
+{
+	struct stat st;
+	return (!stat(s->value, &st) && S_ISDIR(st.st_mode));
+}
+
+
+static bool
+dt_type_device(struct dt_state *s, int nargs)
+{
+	struct stat st;
+	return (!stat(s->value, &st) &&
+	        (S_ISBLK(st.st_mode) || S_ISCHR(st.st_mode)));
+}
+
+static bool
+dt_type_file(struct dt_state *s, int nargs)
+{
+	struct stat st;
+	return (!stat(s->value, &st) && S_ISREG(st.st_mode));
+}
+
+
+static struct dt_fun dt_types[] = {
+	{ "or",				dt_type_or			},
+	{ "and",			dt_type_and			},
+	{ "not",			dt_type_not			},
+	{ "neg",			dt_type_neg			},
+	{ "list",			dt_type_list		},
+	{ "min",			dt_type_min			},
+	{ "max",			dt_type_max			},
+	{ "range",			dt_type_range		},
+	{ "minlength",		dt_type_minlen		},
+	{ "maxlength",		dt_type_maxlen		},
+	{ "rangelength",	dt_type_rangelen	},
+	{ "integer",		dt_type_int			},
+	{ "uinteger",		dt_type_uint		},
+	{ "float",			dt_type_float		},
+	{ "ufloat",			dt_type_ufloat		},
+	{ "bool",			dt_type_bool		},
+	{ "string",			dt_type_string		},
+	{ "ip4addr",		dt_type_ip4addr		},
+	{ "ip6addr",		dt_type_ip6addr		},
+	{ "ipaddr",			dt_type_ipaddr		},
+	{ "cidr4",			dt_type_cidr4		},
+	{ "cidr6",			dt_type_cidr6		},
+	{ "cidr",			dt_type_cidr		},
+	{ "netmask4",		dt_type_netmask4	},
+	{ "netmask6",		dt_type_netmask6	},
+	{ "ipmask4",		dt_type_ipmask4		},
+	{ "ipmask6",		dt_type_ipmask6		},
+	{ "ipmask",			dt_type_ipmask		},
+	{ "port",			dt_type_port		},
+	{ "portrange",		dt_type_portrange	},
+	{ "macaddr",		dt_type_macaddr		},
+	{ "uciname",        dt_type_uciname		},
+	{ "wpakey",			dt_type_wpakey		},
+	{ "wepkey",			dt_type_wepkey		},
+	{ "hostname",		dt_type_hostname	},
+	{ "host",			dt_type_host		},
+	{ "network",		dt_type_network		},
+	{ "phonedigit",		dt_type_phonedigit	},
+	{ "directory",		dt_type_directory	},
+	{ "device",			dt_type_device		},
+	{ "file",			dt_type_file		},
+
+	{ }
+};
+
+static struct dt_fun *
+dt_lookup_function(const char *s, const char *e)
+{
+	struct dt_fun *fun = dt_types;
+
+	while (fun->name)
+	{
+		if (!strncmp(fun->name, s, e - s) && *(fun->name + (e - s)) == '\0')
+			return fun;
+
+		fun++;
+	}
+
+	return NULL;
+}
+
+static bool
+dt_parse_atom(struct dt_state *s, const char *label, const char *end)
+{
+	char q, *e;
+	const char *p;
+	bool esc;
+	double dval;
+	struct dt_fun *func;
+	struct dt_op *op = &s->stack[s->depth];
+
+	if ((s->depth + 1) >= (sizeof(s->stack) / sizeof(s->stack[0])))
+	{
+		printf("Syntax error, expression too long\n");
+		return false;
+	}
+
+	while (isspace(*label))
+		label++;
+
+	/* test whether label is a float */
+	dval = strtod(label, &e);
+
+	if (e > label)
+	{
+		op->next = e;
+		op->type = OP_NUMBER;
+		op->value.number = dval;
+		op->nextop = ++s->depth;
+
+		return true;
+	}
+	else if ((*label == '"') || (*label == '\''))
+	{
+		for (p = label + 1, q = *label, esc = false; p <= end; p++)
+		{
+			if (esc)
+			{
+				esc = false;
+				continue;
+			}
+			else if (*p == '\\')
+			{
+				esc = true;
+				continue;
+			}
+			else if (*p == q)
+			{
+				op->next = p + 1;
+				op->type = OP_STRING;
+				op->length = (p - label) - 2;
+				op->value.string = label + 1;
+				op->nextop = ++s->depth;
+
+				return true;
+			}
+		}
+
+		printf("Syntax error, unterminated string\n");
+		return false;
+	}
+	else if (*label)
+	{
+		for (p = label;
+		     p <= end && ((*p >= 'A' && *p <= 'Z') ||
+		                  (*p >= 'a' && *p <= 'z') ||
+		                  (*p >= '0' && *p <= '9') ||
+		                  (*p == '_'));
+		     p++);
+
+		func = dt_lookup_function(label, p);
+
+		if (!func)
+		{
+			printf("Syntax error, unrecognized function\n");
+			return false;
+		}
+
+		op->next = p;
+		op->type = OP_FUNCTION;
+		op->value.function = func;
+		op->nextop = ++s->depth;
+
+		return true;
+	}
+
+	printf("Syntax error, unexpected EOF\n");
+	return false;
+}
+
+static bool
+dt_parse_list(struct dt_state *s, const char *code, const char *end);
+
+static bool
+dt_parse_expr(const char *code, const char *end, struct dt_state *s)
+{
+	struct dt_op *tok;
+
+	if (!dt_parse_atom(s, code, end))
+		return false;
+
+	tok = &s->stack[s->depth - 1];
+
+	while (isspace(*tok->next))
+		tok->next++;
+
+	if (tok->type == OP_FUNCTION)
+	{
+		if (*tok->next == '(')
+		{
+			end--;
+
+			while (isspace(*end) && end > tok->next + 1)
+				end--;
+
+			return dt_parse_list(s, tok->next + 1, end);
+		}
+		else if (tok->next == end)
+		{
+			return dt_parse_list(s, tok->next, tok->next);
+		}
+
+		printf("Syntax error, expected '(' or EOF after function label\n");
+		return false;
+	}
+	else if (tok->next == end)
+	{
+		return true;
+	}
+
+	printf("Syntax error, expected ',' after literal\n");
+	return false;
+}
+
+static bool
+dt_parse_list(struct dt_state *s, const char *code, const char *end)
+{
+	char c;
+	bool esc;
+	int nest;
+	const char *p, *last;
+	struct dt_op *fptr;
+
+	if (!code)
+		return false;
+
+	fptr = &s->stack[s->depth - 1];
+
+	for (nest = 0, p = last = code, esc = false, c = *p;
+	     p <= end;
+	     p++, c = (p < end) ? *p : '\0')
+	{
+		if (esc)
+		{
+			esc = false;
+			continue;
+		}
+
+		switch (c)
+		{
+		case '\\':
+			esc = true;
+			break;
+
+		case '(':
+			nest++;
+			break;
+
+		case ')':
+			nest--;
+			break;
+
+		case ',':
+		case '\0':
+			if (nest <= 0)
+			{
+				if (p > last)
+				{
+					if (!dt_parse_expr(last, p, s))
+						return false;
+
+					fptr->length++;
+				}
+
+				last = p + 1;
+			}
+
+			break;
+		}
+	}
+
+	fptr->nextop = s->depth;
+	return true;
+}
+
+static bool
+dt_step(struct dt_state *s)
+{
+	bool rv;
+	struct dt_op *op = &s->stack[s->pos];
+
+	switch (op->type)
+	{
+	case OP_BOOL:
+		rv = op->value.boolean;
+		break;
+
+	case OP_NUMBER:
+		rv = dt_test_number(op->value.number, s->value);
+		break;
+
+	case OP_STRING:
+		rv = dt_test_string(op->value.string, op->value.string + op->length, s->value);
+		break;
+
+	case OP_FUNCTION:
+		rv = dt_call(s);
+		break;
+
+	default:
+		rv = false;
+		break;
+	}
+
+	s->pos = op->nextop;
+	return rv;
+}
+
+static bool
+dt_call(struct dt_state *s)
+{
+	bool rv;
+	struct dt_op *fptr = &s->stack[s->pos];
+	struct dt_fun *func = fptr->value.function;
+
+	s->pos++;
+
+	rv = func->call(s, fptr->length);
+
+	s->pos = fptr->nextop;
+
+	return rv;
+}
+
+bool
+dt_parse(const char *code, const char *value)
+{
+	struct dt_state s = {
+		.depth = 1,
+		.stack = {
+			{
+				.type = OP_FUNCTION,
+				.value.function = &dt_types[0],
+				.next = code
+			}
+		}
+	};
+
+	if (!value || !*value)
+		return false;
+
+	if (!dt_parse_list(&s, code, code + strlen(code)))
+		return false;
+
+	s.value = value;
+
+	return dt_call(&s);
+}