/*
   ldb database library

   Copyright (C) Andrew Tridgell  2005
   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2006-2009

     ** NOTE! The following LGPL license applies to the ldb
     ** library. This does NOT imply that all of Samba is released
     ** under the LGPL

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 3 of the License, or (at your option) any later version.

   This library 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
/*
  attribute handlers for well known attribute types, selected by syntax OID
  see rfc2252
*/

#include "ldb_private.h"
#include "system/locale.h"
#include "ldb_handlers.h"

/*
  default handler that just copies a ldb_val.
*/
int ldb_handler_copy(struct ldb_context *ldb, void *mem_ctx,
		     const struct ldb_val *in, struct ldb_val *out)
{
	*out = ldb_val_dup(mem_ctx, in);
	if (in->length > 0 && out->data == NULL) {
		ldb_oom(ldb);
		return -1;
	}
	return 0;
}

/*
  a case folding copy handler, removing leading and trailing spaces and
  multiple internal spaces

  We exploit the fact that utf8 never uses the space octet except for
  the space itself
*/
int ldb_handler_fold(struct ldb_context *ldb, void *mem_ctx,
			    const struct ldb_val *in, struct ldb_val *out)
{
	char *s, *t, *start;
	bool in_space;

	if (!in || !out || !(in->data)) {
		return -1;
	}

	out->data = (uint8_t *)ldb_casefold(ldb, mem_ctx, (const char *)(in->data), in->length);
	if (out->data == NULL) {
		ldb_debug(ldb, LDB_DEBUG_ERROR, "ldb_handler_fold: unable to casefold string [%.*s]", (int)in->length, (const char *)in->data);
		return -1;
	}

	start = (char *)(out->data);
	in_space = true;
	t = start;
	for (s = start; *s != '\0'; s++) {
		if (*s == ' ') {
			if (in_space) {
				/*
				 * We already have one (or this is the start)
				 * and we don't want to add more
				 */
				continue;
			}
			in_space = true;
		} else {
			in_space = false;
		}
		*t = *s;
		t++;
	}

	if (in_space && t != start) {
		/* the loop will have left a single trailing space */
		t--;
	}
	*t = '\0';

	out->length = t - start;
	return 0;
}

/* length limited conversion of a ldb_val to an int64_t */
static int val_to_int64(const struct ldb_val *in, int64_t *v)
{
	char *end;
	char buf[64];

	/* make sure we don't read past the end of the data */
	if (in->length > sizeof(buf)-1) {
		return LDB_ERR_INVALID_ATTRIBUTE_SYNTAX;
	}
	strncpy(buf, (char *)in->data, in->length);
	buf[in->length] = 0;

	*v = (int64_t) strtoll(buf, &end, 0);
	if (*end != 0) {
		return LDB_ERR_INVALID_ATTRIBUTE_SYNTAX;
	}
	return LDB_SUCCESS;
}


/*
  canonicalise a ldap Integer
  rfc2252 specifies it should be in decimal form
*/
static int ldb_canonicalise_Integer(struct ldb_context *ldb, void *mem_ctx,
				    const struct ldb_val *in, struct ldb_val *out)
{
	int64_t i;
	int ret;

	ret = val_to_int64(in, &i);
	if (ret != LDB_SUCCESS) {
		return ret;
	}
	out->data = (uint8_t *) talloc_asprintf(mem_ctx, "%lld", (long long)i);
	if (out->data == NULL) {
		ldb_oom(ldb);
		return LDB_ERR_OPERATIONS_ERROR;
	}
	out->length = strlen((char *)out->data);
	return 0;
}

/*
 * Lexicographically ordered format for a ldap Integer
 *
 * [ INT64_MIN ... -3, -2, -1 | 0 | +1, +2, +3 ... INT64_MAX ]
 *             n                o              p
 *
 * For human readability sake, we continue to format the key as a string
 * (like the canonicalize) rather than store as a fixed binary representation.
 *
 * In order to sort the integers in the correct string order, there are three
 * techniques we use:
 *
 * 1. Zero padding
 * 2. Negative integer inversion
 * 3. 1-byte prefixes: 'n' < 'o' < 'p'
 *
 * 1. To have a fixed-width representation so that 10 sorts after 2 rather than
 * after 1, we zero pad, like this 4-byte width example:
 *
 *     0001, 0002, 0010
 *
 * INT64_MAX = 2^63 - 1 = 9223372036854775807 (19 characters long)
 *
 * Meaning we need to pad to 19 characters.
 *
 * 2. This works for positive integers, but negative integers will still be
 * sorted backwards, for example:
 *
 *     -9223372036854775808 ..., -0000000000000000002, -0000000000000000001
 *          INT64_MIN                    -2                    -1
 *
 *   gets sorted based on string as:
 *
 *     -0000000000000000001, -0000000000000000002, ... -9223372036854775808
 *
 * In order to fix this, we invert the negative integer range, so that they
 * get sorted the same way as positive numbers. INT64_MIN becomes the lowest
 * possible non-negative number (zero), and -1 becomes the highest (INT64_MAX).
 *
 * The actual conversion applied to negative number 'x' is:
 *   INT64_MAX - abs(x) + 1
 * (The +1 is needed because abs(INT64_MIN) is one greater than INT64_MAX)
 *
 * 3. Finally, we now have two different numbers that map to the same key, e.g.
 * INT64_MIN maps to -0000000000000000000 and zero maps to 0000000000000000000.
 * In order to avoid confusion, we give every number a prefix representing its
 * sign: 'n' for negative numbers, 'o' for zero, and 'p' for positive. (Note
 * that '+' and '-' weren't used because they sort the wrong way).
 *
 * The result is a range of key values that look like this:
 *
 *     n0000000000000000000, ... n9223372036854775807,
 *          INT64_MIN                    -1
 *
 *     o0000000000000000000,
 *            ZERO
 *
 *     p0000000000000000001, ... p9223372036854775807
 *            +1                       INT64_MAX
 */
static int ldb_index_format_Integer(struct ldb_context *ldb,
				    void *mem_ctx,
				    const struct ldb_val *in,
				    struct ldb_val *out)
{
	int64_t i;
	int ret;
	char prefix;
	size_t len;

	ret = val_to_int64(in, &i);
	if (ret != LDB_SUCCESS) {
		return ret;
	}

	if (i < 0) {
		/*
		 * i is negative, so this is subtraction rather than
		 * wrap-around.
		 */
		prefix = 'n';
		i = INT64_MAX + i + 1;
	} else if (i > 0) {
		prefix = 'p';
	} else {
		prefix = 'o';
	}

	out->data = (uint8_t *) talloc_asprintf(mem_ctx, "%c%019lld", prefix, (long long)i);
	if (out->data == NULL) {
		ldb_oom(ldb);
		return LDB_ERR_OPERATIONS_ERROR;
	}

	len = talloc_array_length(out->data) - 1;
	if (len != 20) {
		ldb_debug(ldb, LDB_DEBUG_ERROR,
			  __location__ ": expected index format str %s to"
			  " have length 20 but got %zu",
			  (char*)out->data, len);
		return LDB_ERR_OPERATIONS_ERROR;
	}

	out->length = 20;
	return 0;
}

/*
  compare two Integers
*/
static int ldb_comparison_Integer(struct ldb_context *ldb, void *mem_ctx,
				  const struct ldb_val *v1, const struct ldb_val *v2)
{
	int64_t i1=0, i2=0;
	val_to_int64(v1, &i1);
	val_to_int64(v2, &i2);
	if (i1 == i2) return 0;
	return i1 > i2? 1 : -1;
}

/*
  canonicalise a ldap Boolean
  rfc2252 specifies it should be either "TRUE" or "FALSE"
*/
static int ldb_canonicalise_Boolean(struct ldb_context *ldb, void *mem_ctx,
			     const struct ldb_val *in, struct ldb_val *out)
{
	if (in->length >= 4 && strncasecmp((char *)in->data, "TRUE", in->length) == 0) {
		out->data = (uint8_t *)talloc_strdup(mem_ctx, "TRUE");
		out->length = 4;
	} else if (in->length >= 5 && strncasecmp((char *)in->data, "FALSE", in->length) == 0) {
		out->data = (uint8_t *)talloc_strdup(mem_ctx, "FALSE");
		out->length = 5;
	} else {
		return -1;
	}
	return 0;
}

/*
  compare two Booleans
*/
static int ldb_comparison_Boolean(struct ldb_context *ldb, void *mem_ctx,
			   const struct ldb_val *v1, const struct ldb_val *v2)
{
	if (v1->length != v2->length) {
		return v1->length - v2->length;
	}
	return strncasecmp((char *)v1->data, (char *)v2->data, v1->length);
}


/*
  compare two binary blobs
*/
int ldb_comparison_binary(struct ldb_context *ldb, void *mem_ctx,
			  const struct ldb_val *v1, const struct ldb_val *v2)
{
	if (v1->length != v2->length) {
		return v1->length - v2->length;
	}
	return memcmp(v1->data, v2->data, v1->length);
}

/*
  compare two case insensitive strings, ignoring multiple whitespaces
  and leading and trailing whitespaces
  see rfc2252 section 8.1

  try to optimize for the ascii case,
  but if we find out an utf8 codepoint revert to slower but correct function
*/
int ldb_comparison_fold(struct ldb_context *ldb, void *mem_ctx,
			       const struct ldb_val *v1, const struct ldb_val *v2)
{
	const char *s1=(const char *)v1->data, *s2=(const char *)v2->data;
	size_t n1 = v1->length, n2 = v2->length;
	char *b1, *b2;
	const char *u1, *u2;
	int ret;

	while (n1 && *s1 == ' ') { s1++; n1--; };
	while (n2 && *s2 == ' ') { s2++; n2--; };

	while (n1 && n2 && *s1 && *s2) {
		/* the first 127 (0x7F) chars are ascii and utf8 guarantees they
		 * never appear in multibyte sequences */
		if (((unsigned char)s1[0]) & 0x80) goto utf8str;
		if (((unsigned char)s2[0]) & 0x80) goto utf8str;
		if (toupper((unsigned char)*s1) != toupper((unsigned char)*s2))
			break;
		if (*s1 == ' ') {
			while (n1 > 1 && s1[0] == s1[1]) { s1++; n1--; }
			while (n2 > 1 && s2[0] == s2[1]) { s2++; n2--; }
		}
		s1++; s2++;
		n1--; n2--;
	}

	/* check for trailing spaces only if the other pointers has
	 * reached the end of the strings otherwise we can
	 * mistakenly match.  ex. "domain users" <->
	 * "domainUpdates"
	 */
	if (n1 && *s1 == ' ' && (!n2 || !*s2)) {
		while (n1 && *s1 == ' ') { s1++; n1--; }
	}
	if (n2 && *s2 == ' ' && (!n1 || !*s1)) {
		while (n2 && *s2 == ' ') { s2++; n2--; }
	}
	if (n1 == 0 && n2 != 0) {
		return -(int)ldb_ascii_toupper(*s2);
	}
	if (n2 == 0 && n1 != 0) {
		return (int)ldb_ascii_toupper(*s1);
	}
	if (n1 == 0 && n2 == 0) {
		return 0;
	}
	return (int)ldb_ascii_toupper(*s1) - (int)ldb_ascii_toupper(*s2);

utf8str:
	/*
	 * No need to recheck from the start, just from the first utf8 charu
	 * found. Note that the callback of ldb_casefold() needs to be ascii
	 * compatible.
	 */
	b1 = ldb_casefold(ldb, mem_ctx, s1, n1);
	b2 = ldb_casefold(ldb, mem_ctx, s2, n2);

	if (!b1 || !b2) {
		/* One of the strings was not UTF8, so we have no
		 * options but to do a binary compare */
		talloc_free(b1);
		talloc_free(b2);
		ret = memcmp(s1, s2, MIN(n1, n2));
		if (ret == 0) {
			if (n1 == n2) return 0;
			if (n1 > n2) {
				return (int)ldb_ascii_toupper(s1[n2]);
			} else {
				return -(int)ldb_ascii_toupper(s2[n1]);
			}
		}
		return ret;
	}

	u1 = b1;
	u2 = b2;

	while (*u1 & *u2) {
		if (*u1 != *u2)
			break;
		if (*u1 == ' ') {
			while (u1[0] == u1[1]) u1++;
			while (u2[0] == u2[1]) u2++;
		}
		u1++; u2++;
	}
	if (! (*u1 && *u2)) {
		while (*u1 == ' ') u1++;
		while (*u2 == ' ') u2++;
	}
	ret = (int)(*u1 - *u2);

	talloc_free(b1);
	talloc_free(b2);

	return ret;
}


/*
  canonicalise a attribute in DN format
*/
static int ldb_canonicalise_dn(struct ldb_context *ldb, void *mem_ctx,
			       const struct ldb_val *in, struct ldb_val *out)
{
	struct ldb_dn *dn;
	int ret = -1;

	out->length = 0;
	out->data = NULL;

	dn = ldb_dn_from_ldb_val(mem_ctx, ldb, in);
	if ( ! ldb_dn_validate(dn)) {
		return LDB_ERR_INVALID_DN_SYNTAX;
	}

	out->data = (uint8_t *)ldb_dn_alloc_casefold(mem_ctx, dn);
	if (out->data == NULL) {
		goto done;
	}
	out->length = strlen((char *)out->data);

	ret = 0;

done:
	talloc_free(dn);

	return ret;
}

/*
  compare two dns
*/
static int ldb_comparison_dn(struct ldb_context *ldb, void *mem_ctx,
			     const struct ldb_val *v1, const struct ldb_val *v2)
{
	struct ldb_dn *dn1 = NULL, *dn2 = NULL;
	int ret;

	dn1 = ldb_dn_from_ldb_val(mem_ctx, ldb, v1);
	if ( ! ldb_dn_validate(dn1)) return -1;

	dn2 = ldb_dn_from_ldb_val(mem_ctx, ldb, v2);
	if ( ! ldb_dn_validate(dn2)) {
		talloc_free(dn1);
		return -1;
	}

	ret = ldb_dn_compare(dn1, dn2);

	talloc_free(dn1);
	talloc_free(dn2);
	return ret;
}

/*
  compare two utc time values. 1 second resolution
*/
static int ldb_comparison_utctime(struct ldb_context *ldb, void *mem_ctx,
				  const struct ldb_val *v1, const struct ldb_val *v2)
{
	time_t t1=0, t2=0;
	ldb_val_to_time(v1, &t1);
	ldb_val_to_time(v2, &t2);
	if (t1 == t2) return 0;
	return t1 > t2? 1 : -1;
}

/*
  canonicalise a utc time
*/
static int ldb_canonicalise_utctime(struct ldb_context *ldb, void *mem_ctx,
				    const struct ldb_val *in, struct ldb_val *out)
{
	time_t t;
	int ret;
	ret = ldb_val_to_time(in, &t);
	if (ret != LDB_SUCCESS) {
		return ret;
	}
	out->data = (uint8_t *)ldb_timestring_utc(mem_ctx, t);
	if (out->data == NULL) {
		ldb_oom(ldb);
		return LDB_ERR_OPERATIONS_ERROR;
	}
	out->length = strlen((char *)out->data);
	return 0;
}

/*
  canonicalise a generalized time
*/
static int ldb_canonicalise_generalizedtime(struct ldb_context *ldb, void *mem_ctx,
				        const struct ldb_val *in, struct ldb_val *out)
{
	time_t t;
	int ret;
	ret = ldb_val_to_time(in, &t);
	if (ret != LDB_SUCCESS) {
		return ret;
	}
	out->data = (uint8_t *)ldb_timestring(mem_ctx, t);
	if (out->data == NULL) {
		ldb_oom(ldb);
		return LDB_ERR_OPERATIONS_ERROR;
	}
	out->length = strlen((char *)out->data);
	return 0;
}

/*
  table of standard attribute handlers
*/
static const struct ldb_schema_syntax ldb_standard_syntaxes[] = {
	{
		.name            = LDB_SYNTAX_INTEGER,
		.ldif_read_fn    = ldb_handler_copy,
		.ldif_write_fn   = ldb_handler_copy,
		.canonicalise_fn = ldb_canonicalise_Integer,
		.comparison_fn   = ldb_comparison_Integer
	},
	{
		.name            = LDB_SYNTAX_ORDERED_INTEGER,
		.ldif_read_fn    = ldb_handler_copy,
		.ldif_write_fn   = ldb_handler_copy,
		.canonicalise_fn = ldb_canonicalise_Integer,
		.index_format_fn = ldb_index_format_Integer,
		.comparison_fn   = ldb_comparison_Integer
	},
	{
		.name            = LDB_SYNTAX_OCTET_STRING,
		.ldif_read_fn    = ldb_handler_copy,
		.ldif_write_fn   = ldb_handler_copy,
		.canonicalise_fn = ldb_handler_copy,
		.comparison_fn   = ldb_comparison_binary
	},
	{
		.name            = LDB_SYNTAX_DIRECTORY_STRING,
		.ldif_read_fn    = ldb_handler_copy,
		.ldif_write_fn   = ldb_handler_copy,
		.canonicalise_fn = ldb_handler_fold,
		.comparison_fn   = ldb_comparison_fold
	},
	{
		.name            = LDB_SYNTAX_DN,
		.ldif_read_fn    = ldb_handler_copy,
		.ldif_write_fn   = ldb_handler_copy,
		.canonicalise_fn = ldb_canonicalise_dn,
		.comparison_fn   = ldb_comparison_dn
	},
	{
		.name            = LDB_SYNTAX_OBJECTCLASS,
		.ldif_read_fn    = ldb_handler_copy,
		.ldif_write_fn   = ldb_handler_copy,
		.canonicalise_fn = ldb_handler_fold,
		.comparison_fn   = ldb_comparison_fold
	},
	{
		.name            = LDB_SYNTAX_UTC_TIME,
		.ldif_read_fn    = ldb_handler_copy,
		.ldif_write_fn   = ldb_handler_copy,
		.canonicalise_fn = ldb_canonicalise_utctime,
		.comparison_fn   = ldb_comparison_utctime
	},
	{
		.name            = LDB_SYNTAX_GENERALIZED_TIME,
		.ldif_read_fn    = ldb_handler_copy,
		.ldif_write_fn   = ldb_handler_copy,
		.canonicalise_fn = ldb_canonicalise_generalizedtime,
		.comparison_fn   = ldb_comparison_utctime
	},
	{
		.name            = LDB_SYNTAX_BOOLEAN,
		.ldif_read_fn    = ldb_handler_copy,
		.ldif_write_fn   = ldb_handler_copy,
		.canonicalise_fn = ldb_canonicalise_Boolean,
		.comparison_fn   = ldb_comparison_Boolean
	},
};


/*
  return the attribute handlers for a given syntax name
*/
const struct ldb_schema_syntax *ldb_standard_syntax_by_name(struct ldb_context *ldb,
							    const char *syntax)
{
	unsigned int i;
	unsigned num_handlers = sizeof(ldb_standard_syntaxes)/sizeof(ldb_standard_syntaxes[0]);
	/* TODO: should be replaced with a binary search */
	for (i=0;i<num_handlers;i++) {
		if (strcmp(ldb_standard_syntaxes[i].name, syntax) == 0) {
			return &ldb_standard_syntaxes[i];
		}
	}
	return NULL;
}

int ldb_any_comparison(struct ldb_context *ldb, void *mem_ctx,
		       ldb_attr_handler_t canonicalise_fn,
		       const struct ldb_val *v1,
		       const struct ldb_val *v2)
{
	int ret, ret1, ret2;
	struct ldb_val v1_canon, v2_canon;
	TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx);

	/* I could try and bail if tmp_ctx was NULL, but what return
	 * value would I use?
	 *
	 * It seems easier to continue on the NULL context
	 */
	ret1 = canonicalise_fn(ldb, tmp_ctx, v1, &v1_canon);
	ret2 = canonicalise_fn(ldb, tmp_ctx, v2, &v2_canon);

	if (ret1 == LDB_SUCCESS && ret2 == LDB_SUCCESS) {
		ret = ldb_comparison_binary(ldb, mem_ctx, &v1_canon, &v2_canon);
	} else {
		ret = ldb_comparison_binary(ldb, mem_ctx, v1, v2);
	}
	talloc_free(tmp_ctx);
	return ret;
}