/* Copyright (c) 2013 Yoran Heling

  Permission is hereby granted, free of charge, to any person obtaining
  a copy of this software and associated documentation files (the
  "Software"), to deal in the Software without restriction, including
  without limitation the rights to use, copy, modify, merge, publish,
  distribute, sublicense, and/or sell copies of the Software, and to
  permit persons to whom the Software is furnished to do so, subject to
  the following conditions:

  The above copyright notice and this permission notice shall be included
  in all copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
  CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
  TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
  SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/

#include <stdint.h>
#include <stddef.h>


typedef enum {
	YXML_EREF        = -5, /* Invalid character or entity reference (&whatever;) */
	YXML_ECLOSE      = -4, /* Close tag does not match open tag (<Tag> .. </OtherTag>) */
	YXML_ESTACK      = -3, /* Stack overflow (too deeply nested tags or too long element/attribute name) */
	YXML_EATTR       = -2, /* Too long attribute name                    */
	YXML_ESYN        = -1, /* Syntax error (unexpected byte)             */
	YXML_OK          =  0, /* Character consumed, no new token present   */
	YXML_ELEMSTART   =  1, /* Start of an element:   '<Tag ..'           */
	YXML_ELEMEND     =  2, /* End of an element:     '.. />' or '</Tag>' */
	YXML_ATTRSTART   =  4, /* Attribute:             'Name=..'          */
	YXML_ATTREND     =  8, /* End of attribute       '.."'                */
	YXML_CONTENT     = 16, /* Start of element content '.. />' or '.. >' */
	YXML_DATA        = 32, /* Attribute value or element contents        */
	YXML_EOD         = 64  /* End of XML document                        */
} yxml_ret_t;

/* When, exactly, are tokens returned?
 *
 * <TagName
 *   '>' ELEMSTART | CONTENT
 *   '/' ELEMSTART | CONTENT, '>' ELEMENT (| EOD)
 *   ' ' ELEMSTART
 *     '>' CONTENT
 *     '/' CONTENT, '>' ELEMEND (| EOD)
 *     Attr
 *       '=' ATTRSTART
 *         "X DATA
 *           'Y'  DATA
 *             'Z'  DATA
 *               "> ATTREND
 *               "/ CONTENT, '>' ELEMEND (| EOD)
 *
 * </TagName
 *   '>' ELEMEND (| EOD)
 */


typedef struct {
	/* PUBLIC (read-only) */

	/* Name of the current element, zero-length if not in any element. Changed
	 * after YXML_ELEMSTART. The pointer will remain valid up to and including
	 * the next YXML_CONTENT, the pointed-to buffer will remain valid up to and
	 * including the YXML_ELEMCLOSE for the corresponding element. */
	char *elem;

	/* The last read character of an attribute value or element data. Changed
	 * after YXML_DATA and only valid until the next yxml_parse() call. */
	char data;

	/* Name of the current attribute. Changed after YXML_ATTRSTART, valid up to
	 * and including the next YXML_ATTREND. */
	char *attr;

	/* Line number, byte offset within that line, and total bytes read. These
	 * values refer to the position _after_ the last byte given to
	 * yxml_parse(). These are useful for debugging and error reporting. */
	uint64_t byte;
	uint64_t total;
	uint32_t line;


	/* PRIVATE */
	int state;
	unsigned char *stack; /* Stack of element names + attribute name, separated by \0. Also starts with a \0. */
	size_t stacksize, stacklen;
	unsigned char ref[8];
	unsigned reflen;
	unsigned quote;
	int stringstate;
	unsigned ignore;
	unsigned char *string;
} yxml_t;


void yxml_init(yxml_t *x, char *stack, size_t stacksize);


yxml_ret_t yxml_parse(yxml_t *x, int ch);


/* vim: set noet sw=4 ts=4: */