/*  File   : wbxml.c
    Author : Richard A. O'Keefe
    Updated: 06/27/01
    Purpose: Implement WBXML 1.2
*/

#ifndef	lint
static	char SCCSid[] = "@(#)01/06/27 wbxml.c	1.7";
#endif/*lint*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "wbxml.h"

/* The IANA codes for known character sets */

#define IANA_ASCII	3
#define IANA_ISO_8859_1	4
#define IANA_UTF_8	106

/* WBXML byte codes */
#define SWITCH_PAGE	0x00
#define	END		0x01
#define	ENTITY		0x02
#define	STR_I		0x03
#define	LITERAL		0x04
#define	EXT_I_0		0x40
#define	EXT_I_1		0x41
#define	EXT_I_2		0x42
#define	PI		0x43
#define	LITERAL_C	0x44
#define	EXT_T_0		0x80
#define	EXT_T_1		0x81
#define	EXT_T_2		0x82
#define	STR_T		0x83
#define	LITERAL_A	0x84
#define	EXT_0		0xC0
#define	EXT_1		0xC1
#define	EXT_2		0xC2
#define	OPAQUE		0xC3
#define	LITERAL_AC	0xC4

/* Error codes */

#define WBXML_OK	0	/* no error */
#define WBXML_TRUNCATED 1	/* input was truncated */
#define	WBXML_VERSION	2	/* unsupported version number */
#define	WBXML_CHARSET	3	/* unsupported character set number */
#define	WBXML_PUBID	4	/* unsupported public identifier */
#define WBXML_BADDATA	5	/* bad structure */
#define WBXML_UNIMP	6	/* EXT_? and OPAQUE not implemented */
#define WBXML_TOO_BIG   7       /* too much character data at once */
#define WBXML_NO_MEM    8	/* insufficient heap memory */

static int
read_multibyte_word(FILE *stream, unsigned long *result) {
    unsigned long r;
    int c;

    r = 0;
    do {
	c = getc(stream);
	if (c < 0) return 1;
	r = (r << 7) | ((unsigned)c & 0x7Fu);
    } while (((unsigned)c & 0x80u) != 0);
    *result = r;
    return 0;
}

#define err(n) {error_code = n; goto report_error; }

#define get_byte(s, v) \
    if ((c = getc(s)) >= 0) *(v) = (unsigned char)c; else err(WBXML_TRUNCATED)

#define get_word(s, v) \
    if (read_multibyte_word(s, v)) err(WBXML_TRUNCATED)

#define NS (char *)0

static struct WBXML_dictionary *all_dictionaries[] = {
#ifdef TESTING
    &dict1,
    &dict2,
#endif
    &wapdict,
#ifdef HTML
    &htmldict,
#endif
    (struct WBXML_dictionary *)0
};

#define MAX_DATA (4 * 1024 * 1024)
static unsigned char cstack[MAX_DATA];
static int csp = 0;

#define deposit(c) \
    if (csp == MAX_DATA) goto too_much_data; else cstack[csp++] = c

#define MAX_TAGS 1000
struct Tag {
    struct ROKXML_binding *list;
    wchar *name;
    int    csp;
};
static struct Tag tag_stack[MAX_TAGS];
static int        tsp = 0;

static void
free_bindings(struct ROKXML_binding *list) {
    struct ROKXML_binding *p, *q;

    for (p = list; p != 0; p = q) {
	q = p->next;
	free(p);
    }
}

static struct ROKXML_binding *
msort(struct ROKXML_binding *a) {
    struct ROKXML_binding *p, *q, *t, **e;
    int c;

    if ((p = q = a) != 0) {
	while ((p = p->next) != 0 && (p = p->next) != 0) q = q->next;
	if ((p = q->next) != 0) {
	    q->next = 0;
	    q = msort(p);
	    p = msort(a);
	    a = 0;
	    e = &a;
	    while (p != 0 && q != 0) {
		c = strcmp((char const *)p->name, (char const *)q->name);
		if (c <= 0) {
		    if (c == 0) {
		        q = (t = q)->next;
		        free(t);
		    }
		    p = *(e = &(*e = p)->next);
		} else {
		    q = *(e = &(*e = q)->next);
		}
	    }
	    *e = p == 0 ? q : p;
	}
    }
    return a;
}


int wbxml(FILE *stream, struct ROKXML_handlers const *handlers) {
    enum {
	CONT_STATE,	/* processing contents of element or document */
	ATTR_STATE,	/* processing attributes of empty element */
	BOTH_STATE,	/* processing attributes of non-empty element */
	PI_STATE	/* processing processing instruction */
    } state = CONT_STATE;
    unsigned char version;
    unsigned long public_id, public_index;
    unsigned long charset;
    unsigned long strtbl_size;
    unsigned char *strtbl = 0;
    unsigned char const *pubid;
    unsigned char code;
    unsigned long temp;
    unsigned char *src;
    struct WBXML_dictionary *dictionary;
    unsigned char **tags, **atts;
    struct Tag *t;
    struct ROKXML_binding *l;
    unsigned char ch;
    int c;
    int error_code;
    int saved_csp;

    /* version */
    get_byte(stream, &version);
    if (version != 0x02) err(WBXML_VERSION);

    /* public identifier (part 1) */
    get_word(stream, &public_id);
    public_index = 0;
    if (public_id == 0) get_word(stream, &public_index);

    /* character set */
    get_word(stream, &charset);
    if (charset != IANA_ISO_8859_1
     && charset != IANA_UTF_8
     && charset != IANA_ASCII
    ) err(WBXML_CHARSET);
    if (charset == IANA_ASCII) charset = IANA_UTF_8;

    /* String table */
    get_word(stream, &strtbl_size);
    if (strtbl_size == 0) {
	strtbl = (unsigned char *)"";
    } else {
	strtbl = malloc(strtbl_size);
	if (strtbl == 0) err(WBXML_NO_MEM);
	if (fread(strtbl, 1, strtbl_size, stream) != strtbl_size)
	    err(WBXML_TRUNCATED);
    }

    /* public identifier (part 2) */
    switch ((unsigned)public_id) {
	case 0u:
	    if (public_index >= strtbl_size) err(WBXML_BADDATA);
	    pubid = strtbl + public_index;
	    break;
	case 1u:
	    pubid = 0;
	    break;
	case 2u:
	    pubid = (unsigned char const *)"-//WAPFORUM/DTD WML 1.0//EN";
	    break;
	case 4u:
	    pubid = (unsigned char const *)"-//WAPFORUM/DTD WML 1.1//EN";
	    break;
	case 8u:
	    pubid = (unsigned char const *)"-//WAPFORUM/DTD WML 1.2//EN";
	    break;
    /* For testing */
	case 126u:
	    pubid = (unsigned char const *)"-//WAPFORUM/DTD WBXML TEST 1//EN";
	    break;
	case 127u:
	    pubid = (unsigned char const *)"-//WAPFORUM/DTD WBXML TEST 2//EN";
	    break;
    /* End testing */
	case 132u:
	    pubid = (unsigned char const *)"-//W3C/DTD HTML 3.2";
	    break;
	case 133u:
	    pubid = (unsigned char const *)"-//W3C/DTD HTML 4.01 Transitional";
	    break;
	case 134u:
	    pubid = (unsigned char const *)"-//W3C/DTD HTML 4.01 Frameset";
	    break;
	case 135u:
	    pubid = (unsigned char const *)"-//W3C/DTD HTML 4.01 Strict";
	    break;
	default:
	    pubid = (unsigned char *)" ";
    }
    if (pubid == (unsigned char *)0) {
	tags = atts = 0;
    } else {
	int i, j;

	for (i = 0; (dictionary = all_dictionaries[i]) != 0; i++)
	    for (j = 0; dictionary->pubs[j] != 0; j++)
		if (strcmp((char *)dictionary->pubs[j], (char*)pubid) == 0)
		    goto found;
	err(WBXML_PUBID);
found:
	tags = dictionary->tags[0];
	atts = dictionary->atts[0];
    }
    handlers->start(0, pubid);

    /* body of document */
    saved_csp = csp = 0;
    while ((c = getc(stream)) >= 0) {
	code = (unsigned char)c;
	while (code == SWITCH_PAGE) {
	    get_byte(stream, &code);
	    if (state == CONT_STATE) {
		tags = dictionary->tags[code];
	    } else {
		atts = dictionary->atts[code];
	    }
	    get_byte(stream, &code);
	}
	switch (code) {
	    case END:
		if (state != CONT_STATE) {
		    /* end of an attribute list */
		    if (t->list != 0) {deposit(0);}
		    t->list = msort(t->list);
		}
		if (tsp == 0) err(WBXML_BADDATA);
		t = &tag_stack[--tsp];
		switch (state) {
		    case CONT_STATE:
			if (csp != saved_csp) {
			    deposit(0);
			    handlers->text(cstack + saved_csp);
			}
			handlers->end(t->name, t->list);
			break;
		    case ATTR_STATE:
			handlers->empty(t->name, t->list);
			free_bindings(t->list);
			break;
		    case BOTH_STATE:
			handlers->begin(t->name, t->list);
			tsp++;
		        break;
		    case PI_STATE:
			l = t->list;
			if (t->name != 0 || l == 0) err(WBXML_BADDATA);
			handlers->pi(l->name, l->value);
			free_bindings(l);
			break;
		}
		state = CONT_STATE;
		saved_csp = csp = t->csp;
		break;
	    case ENTITY:
		get_word(stream, &temp);
		if (temp < 128) {
		    deposit(temp);
		} else
		if (temp < 32*64) {
		    deposit(temp/64 + 6*32);
		    deposit(temp%64 + 128);
		} else {
		    deposit(temp/4096 + 14*16);
		    deposit((temp/64)%64 + 128);
		    deposit(temp%64 + 128);
		}
		break;
	    case STR_I:
		while ((c = getc(stream)) > 0) {
		    ch = (unsigned char)c;
		    if (charset == IANA_UTF_8 || ch < 128) {
		        deposit(ch);
		    } else {
			deposit((ch>>6) + 6*62);
			deposit((ch&63) + 128);
		    }
		}
		if (c < 0) err(WBXML_TRUNCATED);
		break;
	    case STR_T:
		get_word(stream, &temp);
		if (temp >= strtbl_size) err(WBXML_BADDATA);
		src = strtbl + temp;
		while ((ch = *src++) != 0) {
		    if (charset == IANA_UTF_8 || ch < 128) {
		        deposit(ch);
		    } else {
			deposit((ch>>6) + 6*62);
			deposit((ch&63) + 128);
		    }
		}
		break;
	    case EXT_I_0:
	    case EXT_I_1:
	    case EXT_I_2:
	        deposit('$');
	        deposit('(');
		while ((c = getc(stream)) > 0) {
		    ch = (unsigned char)c;
		    if (charset == IANA_UTF_8 || ch < 128) {
		        deposit(ch);
		    } else {
			deposit((ch>>6) + 6*62);
			deposit((ch&63) + 128);
		    }
		}
		goto rest_ext;
	    case EXT_T_0:	        
	    case EXT_T_1:
	    case EXT_T_2:
	        deposit('$');
	        deposit('(');
		get_word(stream, &temp);
		if (temp >= strtbl_size) err(WBXML_BADDATA);
		src = strtbl + temp;
		while ((ch = *src++) != 0) {
		    if (charset == IANA_UTF_8 || ch < 128) {
		        deposit(ch);
		    } else {
			deposit((ch>>6) + 6*62);
			deposit((ch&63) + 128);
		    }
		}
rest_ext:	{
		    static char *escaping[3] = {":escape", ":unesc", ":noesc"};
		    src = (unsigned char *)escaping[code & 3];
		    while ((ch = *src++) != 0) {
		        deposit(ch);
		    }
		}
		deposit(')');
		break;
	    case EXT_0:
	    case EXT_1:
	    case EXT_2:
	    case OPAQUE:
		/* not used in WML or HTML */
		err(WBXML_UNIMP);
		/*NOTREACHED*/
		break;
	    case PI:
		if (state != CONT_STATE) err(WBXML_BADDATA);
		if (csp != saved_csp) {
		    deposit(0);
		    handlers->text(cstack + saved_csp);
		    csp = saved_csp;
		}
		state = PI_STATE;
		if (tsp == MAX_TAGS) goto too_much_data;
		t = &tag_stack[tsp++];
		t->name = 0, t->list = 0, t->csp = saved_csp = csp;
		break;
	    case LITERAL:
	    case LITERAL_C:
	    case LITERAL_A:
	    case LITERAL_AC:
	        get_word(stream, &temp);
	        if (temp >= strtbl_size) err(WBXML_BADDATA);
	        src = strtbl + temp;
	        goto rest_tag;
	    default:
		if (state != CONT_STATE) {
		    if (atts == 0 || (src = (unsigned char *)atts[code]) == 0)
			err(WBXML_BADDATA);
		    if (code < 128) {
			if (t->list != 0) {deposit(0);}
			saved_csp = csp;
			l = malloc(sizeof *l);
			if (l == 0) err(WBXML_NO_MEM);
			t = &tag_stack[tsp-1];
			l->next = t->list,
			l->name = src,
			l->value = cstack + csp;
			t->list = l;
			src = code == LITERAL ? (unsigned char *)""
			    : src + strlen((char const *)src) + 1;
		    }
		    while ((ch = *src++) != 0) {
			if (charset == IANA_UTF_8 || ch < 128) {
			    deposit(ch);
			} else {
			    deposit((ch>>6) + 6*62);
			    deposit((ch&63) + 128);
			}
		    }
		    break;
		}
		if (tags == 0 || (src = (unsigned char *)tags[code & 63]) == 0)
		    err(WBXML_BADDATA);
rest_tag:	if (csp != saved_csp) {
		    deposit(0);
		    handlers->text(cstack + saved_csp);
		    csp = saved_csp;
		}
	        if ((code & 0xC0) == 0) {
		    handlers->empty(src, 0);
		} else {
		    if (tsp == MAX_TAGS) goto too_much_data;
		    t = &tag_stack[tsp++];
		    t->name = src, t->list = 0, t->csp = saved_csp = csp;
		    switch (code & 0xC0) {
			case 0xC0: state = BOTH_STATE; break;
			case 0x80: state = ATTR_STATE; break;
			case 0x40: state = CONT_STATE;
			    handlers->begin(src, 0);   break;
		    }
		}
		break;
	}
    }

    handlers->finish();
    if (strtbl != 0) free(strtbl);
    return WBXML_OK;
too_much_data:
    error_code = WBXML_TOO_BIG;
report_error:
    if (strtbl != 0) free(strtbl);
    return error_code;
}