/* 	$NetBSD$ */

/*-
 * Copyright (c) 2006 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jason R. Thorpe.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the NetBSD
 *      Foundation, Inc. and its contributors.
 * 4. Neither the name of The NetBSD Foundation nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <prop/proplib.h>
#include "prop_object_impl.h"
#include "prop_codec_impl.h"

#if defined(_KERNEL)
#include <sys/systm.h>
#elif defined(_STANDALONE)
#include <sys/param.h>
#include <lib/libkern/libkern.h>
#else
#include <errno.h>
#include <limits.h>
#include <stdint.h>
#endif

boolean_t	_prop_object_externalize_start_tag(
				struct _prop_object_externalize_context *,
				const char *);
boolean_t	_prop_object_externalize_end_tag(
				struct _prop_object_externalize_context *,
				const char *);
boolean_t	_prop_object_externalize_empty_tag(
				struct _prop_object_externalize_context *,
				const char *);
boolean_t	_prop_object_externalize_append_encoded_cstring(
				struct _prop_object_externalize_context *,
				const char *);
boolean_t	_prop_object_externalize_header(
				struct _prop_object_externalize_context *);
boolean_t	_prop_object_externalize_footer(
				struct _prop_object_externalize_context *);

static boolean_t _prop_object_externalize(
				struct _prop_object_externalize_context *,
				prop_object_t);

typedef enum {
	_PROP_TAG_TYPE_START,			/* e.g. <dict> */
	_PROP_TAG_TYPE_END,			/* e.g. </dict> */
	_PROP_TAG_TYPE_EITHER
} _prop_tag_type_t;

struct _prop_object_internalize_context {
	const char *poic_xml;
	const char *poic_cp;

	const char *poic_tag_start;

	const char *poic_tagname;
	size_t      poic_tagname_len;
	const char *poic_tagattr;
	size_t      poic_tagattr_len;
	const char *poic_tagattrval;
	size_t      poic_tagattrval_len;

	boolean_t   poic_is_empty_element;
	_prop_tag_type_t poic_tag_type;
};

#define	_PROP_EOF(c)		((c) == '\0')
#define	_PROP_ISSPACE(c)	\
	((c) == ' ' || (c) == '\t' || (c) == '\n' || (c) == '\r' || \
	 _PROP_EOF(c))

#define	_PROP_TAG_MATCH(ctx, t)					\
	_prop_object_internalize_match((ctx)->poic_tagname,	\
				       (ctx)->poic_tagname_len,	\
				       (t), strlen(t))

#define	_PROP_TAGATTR_MATCH(ctx, a)				\
	_prop_object_internalize_match((ctx)->poic_tagattr,	\
				       (ctx)->poic_tagattr_len,	\
				       (a), strlen(a))

#define	_PROP_TAGATTRVAL_MATCH(ctx, a)				  \
	_prop_object_internalize_match((ctx)->poic_tagattrval,	  \
				       (ctx)->poic_tagattrval_len,\
				       (a), strlen(a))

boolean_t	_prop_object_internalize_find_tag(
				struct _prop_object_internalize_context *,
				const char *, _prop_tag_type_t);
boolean_t	_prop_object_internalize_match(const char *, size_t,
					       const char *, size_t);
prop_object_t	_prop_object_internalize_by_tag(
				struct _prop_object_internalize_context *);
boolean_t	_prop_object_internalize_decode_string(
				struct _prop_object_internalize_context *,
				char *, size_t, size_t *, const char **);

struct _prop_object_internalize_context *
		_prop_object_internalize_context_alloc(const char *);
void		_prop_object_internalize_context_free(
				struct _prop_object_internalize_context *);

prop_object_t	_prop_array_internalize(
				struct _prop_object_internalize_context *);
prop_object_t	_prop_bool_internalize(
				struct _prop_object_internalize_context *);
prop_object_t	_prop_data_internalize(
				struct _prop_object_internalize_context *);
prop_object_t	_prop_dictionary_internalize(
				struct _prop_object_internalize_context *);
prop_object_t	_prop_number_internalize(
				struct _prop_object_internalize_context *);
prop_object_t	_prop_string_internalize(
				struct _prop_object_internalize_context *);

static char *prop_dictionary_externalize_xml(prop_dictionary_t);
static char *prop_array_externalize_xml(prop_array_t);
static prop_dictionary_t prop_dictionary_internalize_xml(const char *);
static prop_array_t prop_array_internalize_xml(const char *);

const struct _prop_codec prop_codec_xml = {
	.codec_name 			= "xml",
	.codec_sense 			= (const u_char *)"<",
	.codec_dictionary_externalize 	= prop_dictionary_externalize_xml,
	.codec_array_externalize 	= prop_array_externalize_xml,
	.codec_dictionary_internalize 	= prop_dictionary_internalize_xml,
	.codec_array_internalize 	= prop_array_internalize_xml,
};

static boolean_t
_prop_array_externalize(struct _prop_object_externalize_context *ctx,
			void *v)
{
	prop_array_t pa = v;
	struct _prop_object *po;
	prop_object_iterator_t pi;
	unsigned int i;
	boolean_t rv = FALSE;

	_PROP_RWLOCK_RDLOCK(pa->pa_rwlock);

	if (pa->pa_count == 0) {
		_PROP_RWLOCK_UNLOCK(pa->pa_rwlock);
		return (_prop_object_externalize_empty_tag(ctx, "array"));
	}
	
	/* XXXJRT Hint "count" for the internalize step? */
	if (_prop_object_externalize_start_tag(ctx, "array") == FALSE ||
	    _prop_object_externalize_append_char(ctx, '\n') == FALSE)
		goto out;

	pi = prop_array_iterator(pa);
	if (pi == NULL)
		goto out;
	
	ctx->poec_depth++;
	_PROP_ASSERT(ctx->poec_depth != 0);

	while ((po = prop_object_iterator_next(pi)) != NULL) {
		if (_prop_object_externalize(ctx, po) == FALSE) {
			prop_object_iterator_release(pi);
			goto out;
		}
	}

	prop_object_iterator_release(pi);

	ctx->poec_depth--;
	for (i = 0; i < ctx->poec_depth; i++) {
		if (_prop_object_externalize_append_char(ctx, '\t') == FALSE)
			goto out;
	}
	if (_prop_object_externalize_end_tag(ctx, "array") == FALSE)
		goto out;

	rv = TRUE;
	
 out:
 	_PROP_RWLOCK_UNLOCK(pa->pa_rwlock);
	return (rv);
}

/*
 * prop_array_externalize --
 *	Externalize an array, return a NUL-terminated buffer
 *	containing the XML-style representation.  The buffer is allocated
 * 	with the M_TEMP memory type.
 */
static char *
prop_array_externalize_xml(prop_array_t pa)
{
	struct _prop_object_externalize_context *ctx;
	char *cp;

	ctx = _prop_object_externalize_context_alloc();
	if (ctx == NULL)
		return (NULL);
	
	if (_prop_object_externalize_header(ctx) == FALSE ||
	    _prop_object_externalize(ctx, &pa->pa_obj) == FALSE ||
	    _prop_object_externalize_footer(ctx) == FALSE) {
		/* We are responsible for releasing the buffer. */
		_PROP_FREE(ctx->poec_buf, M_TEMP);
		_prop_object_externalize_context_free(ctx);
		return (NULL);
	}

	cp = ctx->poec_buf;
	_prop_object_externalize_context_free(ctx);

	return (cp);
}

/*
 * _prop_array_internalize --
 *	Parse an <array>...</array> and return the object created from the
 *	external representation.
 */
prop_object_t
_prop_array_internalize(struct _prop_object_internalize_context *ctx)
{
	prop_array_t array;
	prop_object_t obj;

	/* We don't currently understand any attributes. */
	if (ctx->poic_tagattr != NULL)
		return (NULL);
	
	array = prop_array_create();
	if (array == NULL)
		return (NULL);
	
	if (ctx->poic_is_empty_element)
		return (array);
	
	for (;;) {
		/* Fetch the next tag. */
		if (_prop_object_internalize_find_tag(ctx, NULL,
					_PROP_TAG_TYPE_EITHER) == FALSE)
			goto bad;

		/* Check to see if this is the end of the array. */
		if (_PROP_TAG_MATCH(ctx, "array") &&
		    ctx->poic_tag_type == _PROP_TAG_TYPE_END)
		    	break;

		/* Fetch the object. */
		obj = _prop_object_internalize_by_tag(ctx);
		if (obj == NULL)
			goto bad;

		if (prop_array_add(array, obj) == FALSE) {
			prop_object_release(obj);
			goto bad;
		}
		prop_object_release(obj);
	}

	return (array);

 bad:
	prop_object_release(array);
	return (NULL);
}

/*
 * prop_array_internalize --
 *	Create an array by parsing the XML-style representation.
 */
static prop_array_t
prop_array_internalize_xml(const char *xml)
{
	prop_array_t array = NULL;
	struct _prop_object_internalize_context *ctx;

	ctx = _prop_object_internalize_context_alloc(xml);
	if (ctx == NULL)
		return (NULL);
	
	/* We start with a <plist> tag. */
	if (_prop_object_internalize_find_tag(ctx, "plist",
					      _PROP_TAG_TYPE_START) == FALSE)
		goto out;
	
	/* Plist elements cannot be empty. */
	if (ctx->poic_is_empty_element)
		goto out;
	
	/*
	 * We don't understand any plist attributes, but Apple XML
	 * property lists often have a "version" attribute.  If we
	 * see that one, we simply ignore it.
	 */
	if (ctx->poic_tagattr != NULL &&
	    !_PROP_TAGATTR_MATCH(ctx, "version"))
	    	goto out;
	
	/* Next we expect to see <array>. */
	if (_prop_object_internalize_find_tag(ctx, "array",
					      _PROP_TAG_TYPE_START) == FALSE)
		goto out;
	
	array = _prop_array_internalize(ctx);
	if (array == NULL)
		goto out;
	
	/* We've advanced past </array>.  Now we want </plist>. */
	if (_prop_object_internalize_find_tag(ctx, "plist",
					      _PROP_TAG_TYPE_END) == FALSE) {
		prop_object_release(array);
		array = NULL;
	}

 out:
	_prop_object_internalize_context_free(ctx);
	return (array);
}

static boolean_t
_prop_bool_externalize(struct _prop_object_externalize_context *ctx,
		       void *v)
{
	prop_bool_t pb = v;

	return (_prop_object_externalize_empty_tag(ctx,
	    prop_bool_true(pb) ? "true" : "false"));
}


/*
 * _prop_bool_internalize --
 *	Parse a <true/> or <false/> and return the object created from
 *	the external representation.
 */
prop_object_t
_prop_bool_internalize(struct _prop_object_internalize_context *ctx)
{
	boolean_t val;

	/* No attributes, and it must be an empty element. */
	if (ctx->poic_tagattr != NULL ||
	    ctx->poic_is_empty_element == FALSE)
	    	return (NULL);

	if (_PROP_TAG_MATCH(ctx, "true"))
		val = TRUE;
	else {
		_PROP_ASSERT(_PROP_TAG_MATCH(ctx, "false"));
		val = FALSE;
	}

	return (prop_bool_create(val));
}
static const char _prop_data_base64[] =
    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
static const char _prop_data_pad64 = '=';

static boolean_t
_prop_data_externalize(struct _prop_object_externalize_context *ctx, void *v)
{
	prop_data_t pd = v;
	size_t i, srclen;
	const uint8_t *src;
	uint8_t output[4];
	uint8_t input[3];

	if (pd->pd_size == 0)
		return (_prop_object_externalize_empty_tag(ctx, "data"));

	if (_prop_object_externalize_start_tag(ctx, "data") == FALSE)
		return (FALSE);

	for (src = pd->pd_immutable, srclen = pd->pd_size;
	     srclen > 2; srclen -= 3) {
		input[0] = *src++;
		input[1] = *src++;
		input[2] = *src++;

		output[0] = (uint32_t)input[0] >> 2;
		output[1] = ((uint32_t)(input[0] & 0x03) << 4) +
		    ((uint32_t)input[1] >> 4);
		output[2] = ((u_int32_t)(input[1] & 0x0f) << 2) +
		    ((uint32_t)input[2] >> 6);
		output[3] = input[2] & 0x3f;
		_PROP_ASSERT(output[0] < 64);
		_PROP_ASSERT(output[1] < 64);
		_PROP_ASSERT(output[2] < 64);
		_PROP_ASSERT(output[3] < 64);

		if (_prop_object_externalize_append_char(ctx,
				_prop_data_base64[output[0]]) == FALSE ||
		    _prop_object_externalize_append_char(ctx,
		    		_prop_data_base64[output[1]]) == FALSE ||
		    _prop_object_externalize_append_char(ctx,
		    		_prop_data_base64[output[2]]) == FALSE ||
		    _prop_object_externalize_append_char(ctx,
		    		_prop_data_base64[output[3]]) == FALSE)
			return (FALSE);
	}

	if (srclen != 0) {
		input[0] = input[1] = input[2] = '\0';
		for (i = 0; i < srclen; i++)
			input[i] = *src++;

		output[0] = (uint32_t)input[0] >> 2;
		output[1] = ((uint32_t)(input[0] & 0x03) << 4) +
		    ((uint32_t)input[1] >> 4);
		output[2] = ((u_int32_t)(input[1] & 0x0f) << 2) +
		    ((uint32_t)input[2] >> 6);
		_PROP_ASSERT(output[0] < 64);
		_PROP_ASSERT(output[1] < 64);
		_PROP_ASSERT(output[2] < 64);

		if (_prop_object_externalize_append_char(ctx,
				_prop_data_base64[output[0]]) == FALSE ||
		    _prop_object_externalize_append_char(ctx,
		    		_prop_data_base64[output[1]]) == FALSE ||
		    _prop_object_externalize_append_char(ctx,
		    		srclen == 1 ? _prop_data_pad64
				: _prop_data_base64[output[2]]) == FALSE ||
		    _prop_object_externalize_append_char(ctx,
		    		_prop_data_pad64) == FALSE)
			return (FALSE);
	}

	if (_prop_object_externalize_end_tag(ctx, "data") == FALSE)
		return (FALSE);
	
	return (TRUE);
}

static boolean_t
_prop_data_internalize_decode(struct _prop_object_internalize_context *ctx,
			     uint8_t *target, size_t targsize, size_t *sizep,
			     const char **cpp)
{
	const char *src;
	size_t tarindex;
	int state, ch;
	const char *pos;

	state = 0;
	tarindex = 0;
	src = ctx->poic_cp;

	for (;;) {
		ch = (unsigned char) *src++;
		if (_PROP_EOF(ch))
			return (FALSE);
		if (_PROP_ISSPACE(ch))
			continue;
		if (ch == '<') {
			src--;
			break;
		}
		if (ch == _prop_data_pad64)
			break;

		pos = strchr(_prop_data_base64, ch);
		if (pos == NULL)
			return (FALSE);

		switch (state) {
		case 0:
			if (target) {
				if (tarindex >= targsize)
					return (FALSE);
				target[tarindex] =
				    (uint8_t)((pos - _prop_data_base64) << 2);
			}
			state = 1;
			break;

		case 1:
			if (target) {
				if (tarindex + 1 >= targsize)
					return (FALSE);
				target[tarindex] |=
				    (uint32_t)(pos - _prop_data_base64) >> 4;
				target[tarindex + 1] =
				    (uint8_t)(((pos - _prop_data_base64) & 0xf)
				        << 4);
			}
			tarindex++;
			state = 2;
			break;

		case 2:
			if (target) {
				if (tarindex + 1 >= targsize)
					return (FALSE);
				target[tarindex] |=
				    (uint32_t)(pos - _prop_data_base64) >> 2;
				target[tarindex + 1] =
				    (uint8_t)(((pos - _prop_data_base64)
				        & 0x3) << 6);
			}
			tarindex++;
			state = 3;
			break;

		case 3:
			if (target) {
				if (tarindex >= targsize)
					return (FALSE);
				target[tarindex] |= (uint8_t)
				    (pos - _prop_data_base64);
			}
			tarindex++;
			state = 0;
			break;

		default:
			_PROP_ASSERT(/*CONSTCOND*/0);
		}
	}

	/*
	 * We are done decoding the Base64 characters.  Let's see if we
	 * ended up on a byte boundary and/or with unrecognized trailing
	 * characters.
	 */
	if (ch == _prop_data_pad64) {
		ch = (unsigned char) *src;	/* src already advanced */
		if (_PROP_EOF(ch))
			return (FALSE);
		switch (state) {
		case 0:		/* Invalid = in first position */
		case 1:		/* Invalid = in second position */
			return (FALSE);

		case 2:		/* Valid, one byte of info */
			/* Skip whitespace */
			for (ch = (unsigned char) *src++;
			     ch != '<'; ch = (unsigned char) *src++) {
				if (_PROP_EOF(ch))
					return (FALSE);
				if (!_PROP_ISSPACE(ch))
					break;
			}
			/* Make sure there is another trailing = */
			if (ch != _prop_data_pad64)
				return (FALSE);
			ch = (unsigned char) *src;
			/* FALLTHROUGH */
		
		case 3:		/* Valid, two bytes of info */
			/*
			 * We know this char is a =.  Is there anything but
			 * whitespace after it?
			 */
			for (; ch != '<'; ch = (unsigned char) *src++) {
				if (_PROP_EOF(ch))
					return (FALSE);
				if (!_PROP_ISSPACE(ch))
					return (FALSE);
			}
		}
	} else {
		/*
		 * We ended by seeing the end of the Base64 string.  Make
		 * sure there are no partial bytes lying around.
		 */
		if (state != 0)
			return (FALSE);
	}

	_PROP_ASSERT(*src == '<');
	if (sizep != NULL)
		*sizep = tarindex;
	if (cpp != NULL)
		*cpp = src;

	return (TRUE);
}

/*
 * _prop_data_internalize --
 *	Parse a <data>...</data> and return the object created from the
 *	external representation.
 */
prop_object_t
_prop_data_internalize(struct _prop_object_internalize_context *ctx)
{
	prop_data_t data;
	uint8_t *buf;
	size_t len, alen;

	/* We don't accept empty elements. */
	if (ctx->poic_is_empty_element)
		return (NULL);
	
	/*
	 * If we got a "size" attribute, get the size of the data blob
	 * from that.  Otherwise, we have to figure it out from the base64.
	 */
	if (ctx->poic_tagattr != NULL) {
		char *cp;

		if (!_PROP_TAGATTR_MATCH(ctx, "size") ||
		    ctx->poic_tagattrval_len == 0)
			return (NULL);

#ifndef _KERNEL
		errno = 0;
#endif
		/* XXX Assumes size_t and unsigned long are the same size. */
		len = strtoul(ctx->poic_tagattrval, &cp, 0);
#ifndef _KERNEL		/* XXX can't check for ERANGE in the kernel */
		if (len == ULONG_MAX && errno == ERANGE)
			return (NULL);
#endif
		if (cp != ctx->poic_tagattrval + ctx->poic_tagattrval_len)
			return (NULL);
		_PROP_ASSERT(*cp == '\"');
	} else if (_prop_data_internalize_decode(ctx, NULL, 0, &len,
						NULL) == FALSE)
		return (NULL);

	/*
	 * Always allocate one extra in case we don't land on an even byte
	 * boundary during the decode.
	 */
	buf = _PROP_MALLOC(len + 1, M_PROP_DATA);
	if (buf == NULL)
		return (NULL);
	
	if (_prop_data_internalize_decode(ctx, buf, len + 1, &alen,
					  &ctx->poic_cp) == FALSE) {
		_PROP_FREE(buf, M_PROP_DATA);
		return (NULL);
	}
	if (alen != len) {
		_PROP_FREE(buf, M_PROP_DATA);
		return (NULL);
	}

	if (_prop_object_internalize_find_tag(ctx, "data",
					      _PROP_TAG_TYPE_END) == FALSE) {
		_PROP_FREE(buf, M_PROP_DATA);
		return (NULL);
	}

	data = _prop_data_alloc();
	if (data == NULL) {
		_PROP_FREE(buf, M_PROP_DATA);
		return (NULL);
	}

	data->pd_mutable = buf;
	data->pd_size = len;

	return (data);
}
static boolean_t
_prop_dict_keysym_externalize(struct _prop_object_externalize_context *ctx,
			     void *v)
{
	prop_dictionary_keysym_t pdk = v;
	const char *s = prop_dictionary_keysym_cstring_nocopy(pdk);

	/* We externalize these as strings, and they're never empty. */

	_PROP_ASSERT(s[0] != '\0');

	if (_prop_object_externalize_start_tag(ctx, "string") == FALSE ||
	    _prop_object_externalize_append_encoded_cstring(ctx, s) == FALSE ||
	    _prop_object_externalize_end_tag(ctx, "string") == FALSE)
		return (FALSE);
	
	return (TRUE);
}

static boolean_t
_prop_dictionary_externalize(struct _prop_object_externalize_context *ctx,
			     void *v)
{
	prop_dictionary_t pd = v;
	prop_dictionary_keysym_t pdk;
	struct _prop_object *po;
	prop_object_iterator_t pi;
	unsigned int i;
	boolean_t rv = FALSE;

	_PROP_RWLOCK_RDLOCK(pd->pd_rwlock);

	if (pd->pd_count == 0) {
		_PROP_RWLOCK_UNLOCK(pd->pd_rwlock);
		return (_prop_object_externalize_empty_tag(ctx, "dict"));
	}

	if (_prop_object_externalize_start_tag(ctx, "dict") == FALSE ||
	    _prop_object_externalize_append_char(ctx, '\n') == FALSE)
		goto out;

	pi = prop_dictionary_iterator(pd);
	if (pi == NULL)
		goto out;
	
	ctx->poec_depth++;
	_PROP_ASSERT(ctx->poec_depth != 0);

	while ((pdk = prop_object_iterator_next(pi)) != NULL) {
		po = prop_dictionary_get_keysym(pd, pdk);
		if (po == NULL ||
		    _prop_object_externalize_start_tag(ctx, "key") == FALSE ||
		    _prop_object_externalize_append_encoded_cstring(ctx,
			prop_dictionary_keysym_cstring_nocopy(pdk)) == FALSE ||
		    _prop_object_externalize_end_tag(ctx, "key") == FALSE ||
		    _prop_object_externalize(ctx, po) == FALSE) {
			prop_object_iterator_release(pi);
			goto out;
		}
	}

	prop_object_iterator_release(pi);

	ctx->poec_depth--;
	for (i = 0; i < ctx->poec_depth; i++) {
		if (_prop_object_externalize_append_char(ctx, '\t') == FALSE)
			goto out;
	}
	if (_prop_object_externalize_end_tag(ctx, "dict") == FALSE)
		goto out;
	
	rv = TRUE;

 out:
	_PROP_RWLOCK_UNLOCK(pd->pd_rwlock);
	return (rv);
}

/*
 * prop_dictionary_externalize --
 *	Externalize a dictionary, returning a NUL-terminated buffer
 *	containing the XML-style representation.  The buffer is allocated
 *	with the M_TEMP memory type.
 */
static char *
prop_dictionary_externalize_xml(prop_dictionary_t pd)
{
	struct _prop_object_externalize_context *ctx;
	char *cp;

	ctx = _prop_object_externalize_context_alloc();
	if (ctx == NULL)
		return (NULL);

	if (_prop_object_externalize_header(ctx) == FALSE ||
	    _prop_object_externalize(ctx, &pd->pd_obj) == FALSE ||
	    _prop_object_externalize_footer(ctx) == FALSE) {
		/* We are responsible for releasing the buffer. */
		_PROP_FREE(ctx->poec_buf, M_TEMP);
		_prop_object_externalize_context_free(ctx);
		return (NULL);
	}

	cp = ctx->poec_buf;
	_prop_object_externalize_context_free(ctx);

	return (cp);
}

/*
 * _prop_dictionary_internalize --
 *	Parse a <dict>...</dict> and return the object created from the
 *	external representation.
 */
prop_object_t
_prop_dictionary_internalize(struct _prop_object_internalize_context *ctx)
{
	prop_dictionary_t dict;
	prop_object_t val;
	size_t keylen;
	char *tmpkey;

	/* We don't currently understand any attributes. */
	if (ctx->poic_tagattr != NULL)
		return (NULL);

	dict = prop_dictionary_create();
	if (dict == NULL)
		return (NULL);

	if (ctx->poic_is_empty_element)
		return (dict);

	tmpkey = _PROP_MALLOC(_PROP_PDK_MAXKEY + 1, M_TEMP);
	if (tmpkey == NULL)
		goto bad;

	for (;;) {
		/* Fetch the next tag. */
		if (_prop_object_internalize_find_tag(ctx, NULL,
					_PROP_TAG_TYPE_EITHER) == FALSE)
			goto bad;

		/* Check to see if this is the end of the dictionary. */
		if (_PROP_TAG_MATCH(ctx, "dict") &&
		    ctx->poic_tag_type == _PROP_TAG_TYPE_END)
			break;

		/* Ok, it must be a non-empty key start tag. */
		if (!_PROP_TAG_MATCH(ctx, "key") ||
		    ctx->poic_tag_type != _PROP_TAG_TYPE_START ||
		    ctx->poic_is_empty_element)
		    	goto bad;

		if (_prop_object_internalize_decode_string(ctx,
						tmpkey, _PROP_PDK_MAXKEY,
						&keylen, &ctx->poic_cp) ==
						FALSE)
			goto bad;

		_PROP_ASSERT(keylen <= _PROP_PDK_MAXKEY);
		tmpkey[keylen] = '\0';

		if (_prop_object_internalize_find_tag(ctx, "key",
					_PROP_TAG_TYPE_END) == FALSE)
			goto bad;
   
		/* ..and now the beginning of the value. */
		if (_prop_object_internalize_find_tag(ctx, NULL,
					_PROP_TAG_TYPE_START) == FALSE)
			goto bad;

		val = _prop_object_internalize_by_tag(ctx);
		if (val == NULL)
			goto bad;

		if (prop_dictionary_set(dict, tmpkey, val) == FALSE) {
			prop_object_release(val);
			goto bad;
		}
		prop_object_release(val);
	}

	_PROP_FREE(tmpkey, M_TEMP);
	return (dict);

 bad:
	if (tmpkey != NULL)
		_PROP_FREE(tmpkey, M_TEMP);
	prop_object_release(dict);
	return (NULL);
}

/*
 * prop_dictionary_internalize --
 *	Create a dictionary by parsing the NUL-terminated XML-style
 *	representation.
 */
static prop_dictionary_t
prop_dictionary_internalize_xml(const char *xml)
{
	prop_dictionary_t dict = NULL;
	struct _prop_object_internalize_context *ctx;

	ctx = _prop_object_internalize_context_alloc(xml);
	if (ctx == NULL)
		return (NULL);

	/* We start with a <plist> tag. */
	if (_prop_object_internalize_find_tag(ctx, "plist",
					      _PROP_TAG_TYPE_START) == FALSE)
		goto out;

	/* Plist elements cannot be empty. */
	if (ctx->poic_is_empty_element)
		goto out;

	/*
	 * We don't understand any plist attributes, but Apple XML
	 * property lists often have a "version" attribute.  If we
	 * see that one, we simply ignore it.
	 */
	if (ctx->poic_tagattr != NULL &&
	    !_PROP_TAGATTR_MATCH(ctx, "version"))
		goto out;

	/* Next we expect to see <dict>. */
	if (_prop_object_internalize_find_tag(ctx, "dict",
					      _PROP_TAG_TYPE_START) == FALSE)
		goto out;

	dict = _prop_dictionary_internalize(ctx);
	if (dict == NULL)
		goto out;

	/* We've advanced past </dict>.  Now we want </plist>. */
	if (_prop_object_internalize_find_tag(ctx, "plist",
					      _PROP_TAG_TYPE_END) == FALSE) {
		prop_object_release(dict);
		dict = NULL;
	}

 out:
 	_prop_object_internalize_context_free(ctx);
	return (dict);
}

static boolean_t
_prop_number_externalize(struct _prop_object_externalize_context *ctx,
			 void *v)
{
	prop_number_t pn = v;
	char tmpstr[32];

	/*
	 * For unsigned numbers, we output in hex.  For signed numbers,
	 * we output in decimal.
	 */
	if (prop_number_unsigned(pn))
		sprintf(tmpstr, "0x%" PRIx64,
		    prop_number_unsigned_integer_value(pn));
	else
		sprintf(tmpstr, "%" PRIi64, prop_number_integer_value(pn));

	if (_prop_object_externalize_start_tag(ctx, "integer") == FALSE ||
	    _prop_object_externalize_append_cstring(ctx, tmpstr) == FALSE ||
	    _prop_object_externalize_end_tag(ctx, "integer") == FALSE)
		return (FALSE);
	
	return (TRUE);
}

static boolean_t
_prop_number_internalize_unsigned(struct _prop_object_internalize_context *ctx,
				  struct _prop_number_value *pnv)
{
	char *cp;

	_PROP_ASSERT(/*CONSTCOND*/sizeof(unsigned long long) ==
		     sizeof(uint64_t));

#ifndef _KERNEL
	errno = 0;
#endif
	pnv->pnv_unsigned = (uint64_t) strtoull(ctx->poic_cp, &cp, 0);
#ifndef _KERNEL		/* XXX can't check for ERANGE in the kernel */
	if (pnv->pnv_unsigned == UINT64_MAX && errno == ERANGE)
		return (FALSE);
#endif
	pnv->pnv_is_unsigned = TRUE;
	ctx->poic_cp = cp;

	return (TRUE);
}

static boolean_t
_prop_number_internalize_signed(struct _prop_object_internalize_context *ctx,
				struct _prop_number_value *pnv)
{
	char *cp;

	_PROP_ASSERT(/*CONSTCOND*/sizeof(long long) == sizeof(int64_t));

#ifndef _KERNEL
	errno = 0;
#endif
	pnv->pnv_signed = (int64_t) strtoll(ctx->poic_cp, &cp, 0);
#ifndef _KERNEL		/* XXX can't check for ERANGE in the kernel */
	if ((pnv->pnv_signed == INT64_MAX || pnv->pnv_signed == INT64_MIN) &&
	    errno == ERANGE)
	    	return (FALSE);
#endif
	pnv->pnv_is_unsigned = FALSE;
	ctx->poic_cp = cp;

	return (TRUE);
}

/*
 * _prop_number_internalize --
 *	Parse a <number>...</number> and return the object created from
 *	the external representation.
 */
prop_object_t
_prop_number_internalize(struct _prop_object_internalize_context *ctx)
{
	struct _prop_number_value pnv;

	memset(&pnv, 0, sizeof(pnv));

	/* No attributes, no empty elements. */
	if (ctx->poic_tagattr != NULL || ctx->poic_is_empty_element)
		return (NULL);

	/*
	 * If the first character is '-', then we treat as signed.
	 * If the first two characters are "0x" (i.e. the number is
	 * in hex), then we treat as unsigned.  Otherwise, we try
	 * signed first, and if that fails (presumably due to ERANGE),
	 * then we switch to unsigned.
	 */
	if (ctx->poic_cp[0] == '-') {
		if (_prop_number_internalize_signed(ctx, &pnv) == FALSE)
			return (NULL);
	} else if (ctx->poic_cp[0] == '0' && ctx->poic_cp[1] == 'x') {
		if (_prop_number_internalize_unsigned(ctx, &pnv) == FALSE)
			return (NULL);
	} else {
		if (_prop_number_internalize_signed(ctx, &pnv) == FALSE &&
		    _prop_number_internalize_unsigned(ctx, &pnv) == FALSE)
		    	return (NULL);
	}

	if (_prop_object_internalize_find_tag(ctx, "integer",
					      _PROP_TAG_TYPE_END) == FALSE)
		return (NULL);

	return (_prop_number_alloc(&pnv));
}
/*
 * _prop_object_externalize_start_tag --
 *	Append an XML-style start tag to the externalize buffer.
 */
boolean_t
_prop_object_externalize_start_tag(
    struct _prop_object_externalize_context *ctx, const char *tag)
{
	unsigned int i;

	for (i = 0; i < ctx->poec_depth; i++) {
		if (_prop_object_externalize_append_char(ctx, '\t') == FALSE)
			return (FALSE);
	}
	if (_prop_object_externalize_append_char(ctx, '<') == FALSE ||
	    _prop_object_externalize_append_cstring(ctx, tag) == FALSE ||
	    _prop_object_externalize_append_char(ctx, '>') == FALSE)
		return (FALSE);
	
	return (TRUE);
}

/*
 * _prop_object_externalize_end_tag --
 *	Append an XML-style end tag to the externalize buffer.
 */
boolean_t
_prop_object_externalize_end_tag(
    struct _prop_object_externalize_context *ctx, const char *tag)
{

	if (_prop_object_externalize_append_char(ctx, '<') == FALSE ||
	    _prop_object_externalize_append_char(ctx, '/') == FALSE ||
	    _prop_object_externalize_append_cstring(ctx, tag) == FALSE ||
	    _prop_object_externalize_append_char(ctx, '>') == FALSE ||
	    _prop_object_externalize_append_char(ctx, '\n') == FALSE)
		return (FALSE);

	return (TRUE);
}

/*
 * _prop_object_externalize_empty_tag --
 *	Append an XML-style empty tag to the externalize buffer.
 */
boolean_t
_prop_object_externalize_empty_tag(
    struct _prop_object_externalize_context *ctx, const char *tag)
{
	unsigned int i;

	for (i = 0; i < ctx->poec_depth; i++) {
		if (_prop_object_externalize_append_char(ctx, '\t') == FALSE)
			return (FALSE);
	}

	if (_prop_object_externalize_append_char(ctx, '<') == FALSE ||
	    _prop_object_externalize_append_cstring(ctx, tag) == FALSE ||
	    _prop_object_externalize_append_char(ctx, '/') == FALSE ||
	    _prop_object_externalize_append_char(ctx, '>') == FALSE ||
	    _prop_object_externalize_append_char(ctx, '\n') == FALSE)
	    	return (FALSE);
	
	return (TRUE);
}

/*
 * _prop_object_externalize_append_encoded_cstring --
 *	Append an encoded C string to the externalize buffer.
 */
boolean_t
_prop_object_externalize_append_encoded_cstring(
    struct _prop_object_externalize_context *ctx, const char *cp)
{

	while (*cp != '\0') {
		switch (*cp) {
		case '<':
			if (_prop_object_externalize_append_cstring(ctx,
					"&lt;") == FALSE)
				return (FALSE);
			break;
		case '>':
			if (_prop_object_externalize_append_cstring(ctx,
					"&gt;") == FALSE)
				return (FALSE);
			break;
		case '&':
			if (_prop_object_externalize_append_cstring(ctx,
					"&amp;") == FALSE)
				return (FALSE);
			break;
		default:
			if (_prop_object_externalize_append_char(ctx,
					(unsigned char) *cp) == FALSE)
				return (FALSE);
			break;
		}
		cp++;
	}

	return (TRUE);
}

/*
 * _prop_object_externalize_header --
 *	Append the standard XML header to the externalize buffer.
 */
boolean_t
_prop_object_externalize_header(struct _prop_object_externalize_context *ctx)
{
	static const char _plist_xml_header[] =
"<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
"<!DOCTYPE plist PUBLIC \"-//Apple Computer//DTD PLIST 1.0//EN\" \"http://www.apple.com/DTDs/PropertyList-1.0.dtd\">\n";

	if (_prop_object_externalize_append_cstring(ctx,
						 _plist_xml_header) == FALSE ||
	    _prop_object_externalize_start_tag(ctx,
				       "plist version=\"1.0\"") == FALSE ||
	    _prop_object_externalize_append_char(ctx, '\n') == FALSE)
		return (FALSE);

	return (TRUE);
}

/*
 * _prop_object_externalize_footer --
 *	Append the standard XML footer to the externalize buffer.  This
 *	also NUL-terminates the buffer.
 */
boolean_t
_prop_object_externalize_footer(struct _prop_object_externalize_context *ctx)
{

	if (_prop_object_externalize_end_tag(ctx, "plist") == FALSE ||
	    _prop_object_externalize_append_char(ctx, '\0') == FALSE)
		return (FALSE);

	return (TRUE);
}

/*
 * _prop_object_internalize_skip_comment --
 *	Skip the body and end tag of a comment.
 */
static boolean_t
_prop_object_internalize_skip_comment(
				struct _prop_object_internalize_context *ctx)
{
	const char *cp = ctx->poic_cp;

	while (!_PROP_EOF(*cp)) {
		if (cp[0] == '-' &&
		    cp[1] == '-' &&
		    cp[2] == '>') {
			ctx->poic_cp = cp + 3;
			return (TRUE);
		}
		cp++;
	}

	return (FALSE);		/* ran out of buffer */
}

/*
 * _prop_object_internalize_find_tag --
 *	Find the next tag in an XML stream.  Optionally compare the found
 *	tag to an expected tag name.  State of the context is undefined
 *	if this routine returns FALSE.  Upon success, the context points
 *	to the first octet after the tag.
 */
boolean_t
_prop_object_internalize_find_tag(struct _prop_object_internalize_context *ctx,
		      const char *tag, _prop_tag_type_t type)
{
	const char *cp;
	size_t taglen;

	if (tag != NULL)
		taglen = strlen(tag);
	else
		taglen = 0;

 start_over:
	cp = ctx->poic_cp;

	/*
	 * Find the start of the tag.
	 */
	while (_PROP_ISSPACE(*cp))
		cp++;
	if (_PROP_EOF(*cp))
		return (FALSE);

	if (*cp != '<')
		return (FALSE);

	ctx->poic_tag_start = cp++;
	if (_PROP_EOF(*cp))
		return (FALSE);

	if (*cp == '!') {
		if (cp[1] != '-' || cp[2] != '-')
			return (FALSE);
		/*
		 * Comment block -- only allowed if we are allowed to
		 * return a start tag.
		 */
		if (type == _PROP_TAG_TYPE_END)
			return (FALSE);
		ctx->poic_cp = cp + 3;
		if (_prop_object_internalize_skip_comment(ctx) == FALSE)
			return (FALSE);
		goto start_over;
	}

	if (*cp == '/') {
		if (type != _PROP_TAG_TYPE_END &&
		    type != _PROP_TAG_TYPE_EITHER)
			return (FALSE);
		cp++;
		if (_PROP_EOF(*cp))
			return (FALSE);
		ctx->poic_tag_type = _PROP_TAG_TYPE_END;
	} else {
		if (type != _PROP_TAG_TYPE_START &&
		    type != _PROP_TAG_TYPE_EITHER)
			return (FALSE);
		ctx->poic_tag_type = _PROP_TAG_TYPE_START;
	}

	ctx->poic_tagname = cp;

	while (!_PROP_ISSPACE(*cp) && *cp != '/' && *cp != '>')
		cp++;
	if (_PROP_EOF(*cp))
		return (FALSE);

	ctx->poic_tagname_len = cp - ctx->poic_tagname;

	/* Make sure this is the tag we're looking for. */
	if (tag != NULL &&
	    (taglen != ctx->poic_tagname_len ||
	     memcmp(tag, ctx->poic_tagname, taglen) != 0))
		return (FALSE);
	
	/* Check for empty tag. */
	if (*cp == '/') {
		if (ctx->poic_tag_type != _PROP_TAG_TYPE_START)
			return(FALSE);		/* only valid on start tags */
		ctx->poic_is_empty_element = TRUE;
		cp++;
		if (_PROP_EOF(*cp) || *cp != '>')
			return (FALSE);
	} else
		ctx->poic_is_empty_element = FALSE;

	/* Easy case of no arguments. */
	if (*cp == '>') {
		ctx->poic_tagattr = NULL;
		ctx->poic_tagattr_len = 0;
		ctx->poic_tagattrval = NULL;
		ctx->poic_tagattrval_len = 0;
		ctx->poic_cp = cp + 1;
		return (TRUE);
	}

	_PROP_ASSERT(!_PROP_EOF(*cp));
	cp++;
	if (_PROP_EOF(*cp))
		return (FALSE);

	while (_PROP_ISSPACE(*cp))
		cp++;
	if (_PROP_EOF(*cp))
		return (FALSE);

	ctx->poic_tagattr = cp;

	while (!_PROP_ISSPACE(*cp) && *cp != '=')
		cp++;
	if (_PROP_EOF(*cp))
		return (FALSE);

	ctx->poic_tagattr_len = cp - ctx->poic_tagattr;
	
	cp++;
	if (*cp != '\"')
		return (FALSE);
	cp++;
	if (_PROP_EOF(*cp))
		return (FALSE);
	
	ctx->poic_tagattrval = cp;
	while (*cp != '\"')
		cp++;
	if (_PROP_EOF(*cp))
		return (FALSE);
	ctx->poic_tagattrval_len = cp - ctx->poic_tagattrval;
	
	cp++;
	if (*cp != '>')
		return (FALSE);

	ctx->poic_cp = cp + 1;
	return (TRUE);
}

/*
 * _prop_object_internalize_decode_string --
 *	Decode an encoded string.
 */
boolean_t
_prop_object_internalize_decode_string(
				struct _prop_object_internalize_context *ctx,
				char *target, size_t targsize, size_t *sizep,
				const char **cpp)
{
	const char *src;
	size_t tarindex;
	char c;
	
	tarindex = 0;
	src = ctx->poic_cp;

	for (;;) {
		if (_PROP_EOF(*src))
			return (FALSE);
		if (*src == '<') {
			break;
		}

		if ((c = *src) == '&') {
			if (src[1] == 'a' &&
			    src[2] == 'm' &&
			    src[3] == 'p' &&
			    src[4] == ';') {
			    	c = '&';
				src += 5;
			} else if (src[1] == 'l' &&
				   src[2] == 't' &&
				   src[3] == ';') {
				c = '<';
				src += 4;
			} else if (src[1] == 'g' &&
				   src[2] == 't' &&
				   src[3] == ';') {
				c = '>';
				src += 4;
			} else if (src[1] == 'a' &&
				   src[2] == 'p' &&
				   src[3] == 'o' &&
				   src[4] == 's' &&
				   src[5] == ';') {
				c = '\'';
				src += 6;
			} else if (src[1] == 'q' &&
				   src[2] == 'u' &&
				   src[3] == 'o' &&
				   src[4] == 't' &&
				   src[5] == ';') {
				c = '\"';
				src += 6;
			} else
				return (FALSE);
		} else
			src++;
		if (target) {
			if (tarindex >= targsize)
				return (FALSE);
			target[tarindex] = c;
		}
		tarindex++;
	}

	_PROP_ASSERT(*src == '<');
	if (sizep != NULL)
		*sizep = tarindex;
	if (cpp != NULL)
		*cpp = src;
	
	return (TRUE);
}

/*
 * _prop_object_internalize_match --
 *	Returns true if the two character streams match.
 */
boolean_t
_prop_object_internalize_match(const char *str1, size_t len1,
			       const char *str2, size_t len2)
{

	return (len1 == len2 && memcmp(str1, str2, len1) == 0);
}

#define	INTERNALIZER(t, f)			\
{	t,	sizeof(t) - 1,		f	}

static const struct _prop_object_internalizer {
	const char	*poi_tag;
	size_t		poi_taglen;
	prop_object_t	(*poi_intern)(
				struct _prop_object_internalize_context *);
} _prop_object_internalizer_table[] = {
	INTERNALIZER("array", _prop_array_internalize),

	INTERNALIZER("true", _prop_bool_internalize),
	INTERNALIZER("false", _prop_bool_internalize),

	INTERNALIZER("data", _prop_data_internalize),

	INTERNALIZER("dict", _prop_dictionary_internalize),

	INTERNALIZER("integer", _prop_number_internalize),

	INTERNALIZER("string", _prop_string_internalize),

	{ 0, 0, NULL }
};

#undef INTERNALIZER

/*
 * _prop_object_internalize_by_tag --
 *	Determine the object type from the tag in the context and
 *	internalize it.
 */
prop_object_t
_prop_object_internalize_by_tag(struct _prop_object_internalize_context *ctx)
{
	const struct _prop_object_internalizer *poi;

	for (poi = _prop_object_internalizer_table;
	     poi->poi_tag != NULL; poi++) {
		if (_prop_object_internalize_match(ctx->poic_tagname,
						   ctx->poic_tagname_len,
						   poi->poi_tag,
						   poi->poi_taglen))
			return ((*poi->poi_intern)(ctx));
	}

	return (NULL);
}

/*
 * _prop_object_internalize_context_alloc --
 *	Allocate an internalize context.
 */
struct _prop_object_internalize_context *
_prop_object_internalize_context_alloc(const char *xml)
{
	struct _prop_object_internalize_context *ctx;

	ctx = _PROP_MALLOC(sizeof(struct _prop_object_internalize_context),
			   M_TEMP);
	if (ctx == NULL)
		return (NULL);
	
	ctx->poic_xml = ctx->poic_cp = xml;

	/*
	 * Skip any whitespace and XML preamble stuff that we don't
	 * know about / care about.
	 */
	for (;;) {
		while (_PROP_ISSPACE(*xml))
			xml++;
		if (_PROP_EOF(*xml) || *xml != '<')
			goto bad;

#define	MATCH(str)	(memcmp(&xml[1], str, sizeof(str) - 1) == 0)

		/*
		 * Skip over the XML preamble that Apple XML property
		 * lists usually include at the top of the file.
		 */
		if (MATCH("?xml ") ||
		    MATCH("!DOCTYPE plist")) {
			while (*xml != '>' && !_PROP_EOF(*xml))
				xml++;
			if (_PROP_EOF(*xml))
				goto bad;
			xml++;	/* advance past the '>' */
			continue;
		}

		if (MATCH("<!--")) {
			ctx->poic_cp = xml + 4;
			if (_prop_object_internalize_skip_comment(ctx) == FALSE)
				goto bad;
			xml = ctx->poic_cp;
			continue;
		}

#undef MATCH

		/*
		 * We don't think we should skip it, so let's hope we can
		 * parse it.
		 */
		break;
	}

	ctx->poic_cp = xml;
	return (ctx);
 bad:
	_PROP_FREE(ctx, M_TEMP);
	return (NULL);
}

/*
 * _prop_object_internalize_context_free --
 *	Free an internalize context.
 */
void
_prop_object_internalize_context_free(
		struct _prop_object_internalize_context *ctx)
{

	_PROP_FREE(ctx, M_TEMP);
}

static boolean_t
_prop_string_externalize(struct _prop_object_externalize_context *ctx,
			 void *v)
{
	prop_string_t ps = v;

	if (ps->ps_size == 0)
		return (_prop_object_externalize_empty_tag(ctx, "string"));

	if (_prop_object_externalize_start_tag(ctx, "string") == FALSE ||
	    _prop_object_externalize_append_encoded_cstring(ctx,
	    					ps->ps_immutable) == FALSE ||
	    _prop_object_externalize_end_tag(ctx, "string") == FALSE)
		return (FALSE);
	
	return (TRUE);
}

/*
 * _prop_string_internalize --
 *	Parse a <string>...</string> and return the object created from the
 *	external representation.
 */
prop_object_t
_prop_string_internalize(struct _prop_object_internalize_context *ctx)
{
	prop_string_t string;
	char *str;
	size_t len, alen;

	if (ctx->poic_is_empty_element)
		return (prop_string_create());
	
	/* No attributes recognized here. */
	if (ctx->poic_tagattr != NULL)
		return (NULL);

	/* Compute the length of the result. */
	if (_prop_object_internalize_decode_string(ctx, NULL, 0, &len,
						   NULL) == FALSE)
		return (NULL);
	
	str = _PROP_MALLOC(len + 1, M_PROP_STRING);
	if (str == NULL)
		return (NULL);
	
	if (_prop_object_internalize_decode_string(ctx, str, len, &alen,
						   &ctx->poic_cp) == FALSE ||
	    alen != len) {
		_PROP_FREE(str, M_PROP_STRING);
		return (NULL);
	}
	str[len] = '\0';

	if (_prop_object_internalize_find_tag(ctx, "string",
					      _PROP_TAG_TYPE_END) == FALSE) {
		_PROP_FREE(str, M_PROP_STRING);
		return (NULL);
	}

	string = _prop_string_alloc();
	if (string == NULL) {
		_PROP_FREE(str, M_PROP_STRING);
		return (NULL);
	}

	string->ps_mutable = str;
	string->ps_size = len;

	return (string);
}

static boolean_t
_prop_object_externalize(struct _prop_object_externalize_context *ctx,
    prop_object_t o)
{
	switch (prop_object_type(o)) {
	case PROP_TYPE_BOOL:
		return _prop_bool_externalize(ctx, o);
	case PROP_TYPE_NUMBER:
		return _prop_number_externalize(ctx, o);
	case PROP_TYPE_STRING:
		return _prop_string_externalize(ctx, o);
	case PROP_TYPE_DATA:
		return _prop_data_externalize(ctx, o);
	case PROP_TYPE_ARRAY:
		return _prop_array_externalize(ctx, o);
	case PROP_TYPE_DICTIONARY:
		return _prop_dictionary_externalize(ctx, o);
	case PROP_TYPE_DICT_KEYSYM:
		return _prop_dict_keysym_externalize(ctx, o);
	default:
		return (FALSE);
	}
}