cclfind.c

harvest是一个下载html网页得机器人

/*
 * Copyright (c) 1995, the EUROPAGATE consortium (see below).
 *
 * The EUROPAGATE consortium members are:
 *
 *    University College Dublin
 *    Danmarks Teknologiske Videnscenter
 *    An Chomhairle Leabharlanna
 *    Consejo Superior de Investigaciones Cientificas
 *
 * Permission to use, copy, modify, distribute, and sell this software and
 * its documentation, in whole or in part, for any purpose, is hereby granted,
 * provided that:
 *
 * 1. This copyright and permission notice appear in all copies of the
 * software and its documentation. Notices of copyright or attribution
 * which appear at the beginning of any file must remain unchanged.
 *
 * 2. The names of EUROPAGATE or the project partners may not be used to
 * endorse or promote products derived from this software without specific
 * prior written permission.
 *
 * 3. Users of this software (implementors and gateway operators) agree to
 * inform the EUROPAGATE consortium of their use of the software. This
 * information will be used to evaluate the EUROPAGATE project and the
 * software, and to plan further developments. The consortium may use
 * the information in later publications.
 * 
 * 4. Users of this software agree to make their best efforts, when
 * documenting their use of the software, to acknowledge the EUROPAGATE
 * consortium, and the role played by the software in their work.
 *
 * THIS SOFTWARE IS PROVIDED "AS IS" AND WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS, IMPLIED, OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
 * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
 * IN NO EVENT SHALL THE EUROPAGATE CONSORTIUM OR ITS MEMBERS BE LIABLE
 * FOR ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF
 * ANY KIND, OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA
 * OR PROFITS, WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND
 * ON ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE
 * USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 */
/* CCL find (to rpn conversion)
 * Europagate, 1995
 *
 * $Id: cclfind.c,v 1.34 2003/06/23 10:22:21 adam Exp $
 *
 * Old Europagate log:
 *
 * Revision 1.16  1996/01/08  08:41:13  adam
 * Removed unused function.
 *
 * Revision 1.15  1995/07/20  08:14:34  adam
 * Qualifiers were observed too often. Instead tokens are treated as
 * qualifiers only when separated by comma.
 *
 * Revision 1.14  1995/05/16  09:39:26  adam
 * LICENSE.
 *
 * Revision 1.13  1995/04/17  09:31:42  adam
 * Improved handling of qualifiers. Aliases or reserved words.
 *
 * Revision 1.12  1995/03/20  15:27:43  adam
 * Minor changes.
 *
 * Revision 1.11  1995/02/23  08:31:59  adam
 * Changed header.
 *
 * Revision 1.9  1995/02/16  13:20:06  adam
 * Spell fix.
 *
 * Revision 1.8  1995/02/14  19:59:42  adam
 * Removed a syntax error.
 *
 * Revision 1.7  1995/02/14  19:55:10  adam
 * Header files ccl.h/cclp.h are gone! They have been merged an
 * moved to ../include/ccl.h.
 * Node kind(s) in ccl_rpn_node have changed names.
 *
 * Revision 1.6  1995/02/14  16:20:55  adam
 * Qualifiers are read from a file now.
 *
 * Revision 1.5  1995/02/14  14:12:41  adam
 * Ranges for ordered qualfiers implemented (e.g. pd=1980-1990).
 *
 * Revision 1.4  1995/02/14  13:16:29  adam
 * Left and/or right truncation implemented.
 *
 * Revision 1.3  1995/02/14  10:25:56  adam
 * The constructions 'qualifier rel term ...' implemented.
 *
 * Revision 1.2  1995/02/13  15:15:07  adam
 * Added handling of qualifiers. Not finished yet.
 *
 * Revision 1.1  1995/02/13  12:35:20  adam
 * First version of CCL. Qualifiers aren't handled yet.
 *
 */

#include <stdlib.h>
#include <string.h>

#include <yaz/ccl.h>

/* returns type of current lookahead */
#define KIND (cclp->look_token->kind)

/* move one token forward */
#define ADVANCE cclp->look_token = cclp->look_token->next

/* 
 * qual_val_type: test for existance of attribute type/value pair.
 * qa:     Attribute array
 * type:   Type of attribute to search for
 * value:  Value of attribute to seach for
 * return: 1 if found; 0 otherwise.
 */
static int qual_val_type (struct ccl_rpn_attr **qa, int type, int value,
                           char **attset)
{
    int i;
    struct ccl_rpn_attr *q;

    if (!qa)
        return 0;
    for (i = 0;  (q=qa[i]); i++)
        while (q)
        {
            if (q->type == type && q->kind == CCL_RPN_ATTR_NUMERIC &&
		q->value.numeric == value)
            {
                if (attset)
                    *attset = q->set;
                return 1;
            }
            q = q->next;
        }
    return 0;
}

/*
 * strxcat: concatenate strings.
 * n:      Null-terminated Destination string 
 * src:    Source string to be appended (not null-terminated)
 * len:    Length of source string.
 */
static void strxcat (char *n, const char *src, int len)
{
    while (*n)
        n++;
    while (--len >= 0)
        *n++ = *src++;
    *n = '\0';
}

/*
 * copy_token_name: Return copy of CCL token name
 * tp:      Pointer to token info.
 * return:  malloc(3) allocated copy of token name.
 */
static char *copy_token_name (struct ccl_token *tp)
{
    char *str = (char *)xmalloc (tp->len + 1);
    ccl_assert (str);
    memcpy (str, tp->name, tp->len);
    str[tp->len] = '\0';
    return str;
}

/*
 * mk_node: Create RPN node.
 * kind:   Type of node.
 * return: pointer to allocated node.
 */
static struct ccl_rpn_node *mk_node (int kind)
{
    struct ccl_rpn_node *p;
    p = (struct ccl_rpn_node *)xmalloc (sizeof(*p));
    ccl_assert (p);
    p->kind = kind;
    return p;
}

/*
 * ccl_rpn_delete: Delete RPN tree.
 * rpn:   Pointer to tree.
 */
void ccl_rpn_delete (struct ccl_rpn_node *rpn)
{
    struct ccl_rpn_attr *attr, *attr1;
    if (!rpn)
        return;
    switch (rpn->kind)
    {
    case CCL_RPN_AND:
    case CCL_RPN_OR:
    case CCL_RPN_NOT:
        ccl_rpn_delete (rpn->u.p[0]);
        ccl_rpn_delete (rpn->u.p[1]);
        break;
    case CCL_RPN_TERM:
        xfree (rpn->u.t.term);
        for (attr = rpn->u.t.attr_list; attr; attr = attr1)
        {
            attr1 = attr->next;
	    if (attr->kind == CCL_RPN_ATTR_STRING)
		xfree(attr->value.str);
            if (attr->set)
                xfree (attr->set);
            xfree (attr);
        }
        break;
    case CCL_RPN_SET:
        xfree (rpn->u.setname);
        break;
    case CCL_RPN_PROX:
        ccl_rpn_delete (rpn->u.p[0]);
        ccl_rpn_delete (rpn->u.p[1]);
        break;
    }
    xfree (rpn);
}

static struct ccl_rpn_node *find_spec (CCL_parser cclp,
                                       struct ccl_rpn_attr **qa);

static int is_term_ok (int look, int *list)
{
    for (;*list >= 0; list++)
        if (look == *list)
            return 1;
    return 0;
}

static struct ccl_rpn_node *search_terms (CCL_parser cclp,
                                          struct ccl_rpn_attr **qa);

static struct ccl_rpn_attr *add_attr_node (struct ccl_rpn_node *p,
					   const char *set, int type)
{
    struct ccl_rpn_attr *n;
    
    n = (struct ccl_rpn_attr *)xmalloc (sizeof(*n));
    ccl_assert (n);
    if (set)
    {
        n->set = (char*) xmalloc (strlen(set)+1);
        strcpy (n->set, set);
    }
    else
        n->set = 0;
    n->type = type;
    n->next = p->u.t.attr_list;
    p->u.t.attr_list = n;
    
    n->kind = CCL_RPN_ATTR_NUMERIC;
    n->value.numeric = 0;
    return n;
}

/*
 * add_attr_numeric: Add attribute (type/value) to RPN term node.
 * p:     RPN node of type term.
 * type:  Type of attribute
 * value: Value of attribute
 * set: Attribute set name
 */
static void add_attr_numeric (struct ccl_rpn_node *p, const char *set,
			      int type, int value)
{
    struct ccl_rpn_attr *n;

    n = add_attr_node(p, set, type);
    n->kind = CCL_RPN_ATTR_NUMERIC;
    n->value.numeric = value;
}

static void add_attr_string (struct ccl_rpn_node *p, const char *set,
			     int type, char *value)
{
    struct ccl_rpn_attr *n;

    n = add_attr_node(p, set, type);
    n->kind = CCL_RPN_ATTR_STRING;
    n->value.str = xstrdup(value);
}


/*
 * search_term: Parse CCL search term. 
 * cclp:   CCL Parser
 * qa:     Qualifier attributes already applied.
 * term_list: tokens we accept as terms in context
 * multi:  whether we accept "multiple" tokens
 * return: pointer to node(s); NULL on error.
 */
static struct ccl_rpn_node *search_term_x (CCL_parser cclp,
                                           struct ccl_rpn_attr **qa,
                                           int *term_list, int multi)
{
    struct ccl_rpn_node *p_top = 0;
    struct ccl_token *lookahead = cclp->look_token;
    int and_list = 0;
    int or_list = 0;
    char *attset;
    const char *truncation_aliases;

    truncation_aliases =
	ccl_qual_search_special(cclp->bibset, "truncation");
    if (!truncation_aliases)
	truncation_aliases = "?";

    if (qual_val_type (qa, CCL_BIB1_STR, CCL_BIB1_STR_AND_LIST, 0))
        and_list = 1;
    if (qual_val_type (qa, CCL_BIB1_STR, CCL_BIB1_STR_OR_LIST, 0))
        or_list = 1;
    while (1)
    {
        struct ccl_rpn_node *p;
        size_t no, i;
        int no_spaces = 0;
        int left_trunc = 0;
        int right_trunc = 0;
        int mid_trunc = 0;
        int relation_value = -1;
        int position_value = -1;
        int structure_value = -1;
        int truncation_value = -1;
        int completeness_value = -1;
        int len = 0;
        size_t max = 200;
        if (and_list || or_list || !multi)
            max = 1;
	
	/* ignore commas when dealing with and-lists .. */
        if (and_list && lookahead && lookahead->kind == CCL_TOK_COMMA)
        {
	    lookahead = lookahead->next;
            ADVANCE;
	    continue;
        }
        /* go through each TERM token. If no truncation attribute is yet
           met, then look for left/right truncation markers (?) and
           set left_trunc/right_trunc/mid_trunc accordingly */
        for (no = 0; no < max && is_term_ok(lookahead->kind, term_list); no++)
        {
            for (i = 0; i<lookahead->len; i++)
                if (lookahead->name[i] == ' ')
		    no_spaces++;
		else if (strchr(truncation_aliases, lookahead->name[i]))
                {
                    if (no == 0 && i == 0 && lookahead->len >= 1)
                        left_trunc = 1;
                    else if (!is_term_ok(lookahead->next->kind, term_list) &&
                             i == lookahead->len-1 && i >= 1)
                        right_trunc = 1;
                    else
                        mid_trunc = 1;
                }
            len += 1+lookahead->len;
            lookahead = lookahead->next;
        }

        if (len == 0)
            break;      /* no more terms . stop . */


        if (p_top)
        {
            if (or_list)
                p = mk_node (CCL_RPN_OR);