1 /******************************************************************************
2 * Copyright (C) 2008 by Diego Arroyuelo *
3 * Interface for the in-memory XQuery/XPath engine *
5 * This program is free software; you can redistribute it and/or modify *
6 * it under the terms of the GNU Lesser General Public License as published *
7 * by the Free Software Foundation; either version 2 of the License, or *
8 * (at your option) any later version. *
10 * This program is distributed in the hope that it will be useful, *
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of *
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
13 * GNU Lesser General Public License for more details. *
15 * You should have received a copy of the GNU Lesser General Public License *
16 * along with this program; if not, write to the *
17 * Free Software Foundation, Inc., *
18 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
19 ******************************************************************************/
25 #include <unordered_set>
26 #include <unordered_map>
28 #include "TextCollection/TextCollectionBuilder.h"
35 #include <libcds/includes/basics.h>
36 #include <static_bitsequence.h>
37 #include <alphabet_mapper.h>
38 #include <static_sequence.h>
39 using SXSI::TextCollection;
40 using SXSI::TextCollectionBuilder;
43 // this constant is used to efficiently compute the child operation in the tree
48 #define PERM_SAMPLE 10
60 // Encoding of the XML Document :
61 // The following TAGs and IDs are fixed, "" is the tag of the root.
62 // a TextNode is represented by a leaf <<$>></<$>> The DocId in the TextCollection
63 // of that leaf is kept in a bit sequence.
64 // a TextNode below an attribute is likewise represented by a leaf <<@$>><</@$>>
65 // An element <e a1="v1" a2="v2" ... an="vn" > ...</e> the representation is:
66 // <e><<@>> <<@>a1> <<$@>>DocID(v1)</<$@>></<@>a1> ... </<@>> .... </e>
67 // Hence the attributes (if any) are always below the first child of their element,
68 // as the children of a fake node <@>.
71 #define DOCUMENT_OPEN_TAG ""
72 #define DOCUMENT_TAG_ID 0
73 #define ATTRIBUTE_OPEN_TAG "<@>"
74 #define ATTRIBUTE_TAG_ID 1
75 #define PCDATA_OPEN_TAG "<$>"
76 #define PCDATA_TAG_ID 2
77 #define ATTRIBUTE_DATA_OPEN_TAG "<@$>"
78 #define ATTRIBUTE_DATA_TAG_ID 3
79 #define CLOSING_TAG "</>"
80 #define CLOSING_TAG_ID 4
81 #define DOCUMENT_CLOSE_TAG "/"
82 #define ATTRIBUTE_CLOSE_TAG "/<@>"
83 #define PCDATA_CLOSE_TAG "/<$>"
84 #define ATTRIBUTE_DATA_CLOSE_TAG "/<@$>"
87 typedef std::unordered_set<int> TagIdSet;
88 typedef std::unordered_map<std::string,int> TagIdMap;
89 typedef TagIdMap::const_iterator TagIdMapIT;
91 #define REGISTER_TAG(v,h,t) do { (h)->insert(std::make_pair((t),(v)->size()));\
92 (v)->push_back(t); } while (false)
94 // returns NULLT if the test is true
95 #define NULLT_IF(x) do { if (x) return NULLT; } while (0)
97 // Direct calls to sarray library
99 #define BUFFER_ALLOC (8192 * 2)
100 #define BUFFER_SIZE (BUFFER_ALLOC / 2)
101 static inline int fast_find_close(bp *b,int s)
103 return fwd_excess(b,s,-1);
106 static inline int fast_inspect(bp* Par,treeNode i)
111 return (Par->B[j] >> (D-1-l)) & 1;
114 static bool fast_isleaf(bp* Par,treeNode x){
115 return (fast_inspect(Par, x+1) == CP);
118 static treeNode fast_first_child(bp *Par, treeNode x)
121 return (fast_inspect(Par,x) == OP) ? x : NULLT;
124 inline static treeNode fast_next_sibling(bp* Par,treeNode x)
126 treeNode y = fast_find_close(Par,x)+1;
127 return (fast_inspect(Par, y) == OP) ? y : NULLT;
130 inline static bool fast_is_ancestor(bp * Par,treeNode x,treeNode y){
131 return (x <= y) && ((x==0) || (y <= fast_find_close(Par,x)));
134 // tag position -> tree node
135 static treeNode tagpos2node(int t)
139 // tree node -> tag position
140 static int node2tagpos(treeNode x)
146 class XMLTreeBuilder;
150 // Only the builder can access the constructor
151 friend class XMLTreeBuilder;
154 /** Balanced parentheses representation of the tree */
157 /** Mapping from tag identifer to tag name */
158 std::vector<std::string> *TagName;
161 /** Bit vector indicating with a 1 the positions of the non-empty texts. */
162 static_bitsequence *EBVector;
164 /** Tag sequence represented with a data structure for rank and select */
165 static_sequence *Tags;
167 uint tags_blen, tags_len;
169 /** The texts in the XML document */
170 TextCollection *Text;
172 // Allows to disable the TextCollection for benchmarkin purposes
174 SXSI::TextCollectionBuilder::index_type_t text_index_type;
177 std::vector<std::string *> *print_stack;
180 size_t size = buffer->size();
181 if (size < BUFFER_SIZE) return;
184 written = write(fd, buffer->data(), size);
185 if ((written < 0) && (errno == EAGAIN || errno == EINTR))
192 void _dput_str(std::string s, int fd){
197 void _dputs(const char* s, int fd){
202 void _dputc(const char c, int fd){
203 buffer->push_back(c);
206 size_t _dprintf(const char* s, int fd){
207 if (s == NULL) return 0;
210 for (i = 0; (c = s[i]); i++) {
213 _dputs(""", fd);
219 _dputs("'", fd);
235 void PrintNode(treeNode n, int fd);
236 /** Data structure constructors */
237 XMLTree(){ buffer = 0;};
239 // non const pointer are freed by this method.
240 XMLTree( pb * const par,
242 std::vector<std::string> * const TN,
243 TagIdMap * const tim, uint *empty_texts_bmp,
245 TextCollection * const TC, bool dis_tc,
246 TextCollectionBuilder::index_type_t _index_type );
249 /** Data structure destructor */
252 /** root(): returns the tree root. */
253 treeNode Root() { return 0; }
255 /** Size() : Number of parenthesis */
261 /** NumTags() : Number of distinct tags */
262 unsigned int NumTags() {
263 return TagName->size();
266 int TagsBinaryLength(){ return tags_blen; };
267 unsigned int TagStructLength(){ return uint_len(tags_blen,tags_len); };
268 unsigned int * TagStruct() { return tags_fix; };
271 /** SubtreeSize(x): the number of nodes (and attributes) in the subtree of
273 int SubtreeSize(treeNode x) { return subtree_size(Par, x); }
275 /** SubtreeTags(x,tag): the number of occurrences of tag within the subtree
277 int SubtreeTags(treeNode x, TagType tag){
278 //int s = x + 2*subtree_size(Par, x) - 1;
279 treeNode y = fast_find_close(Par, x);
283 for(int i = x; i < y; i++)
284 count += (Tag(i) == tag);
288 return (Tags->rank(tag, y) - Tags->rank(tag, x));
291 /** SubtreeElements(x) of element nodes in the subtree of x
293 int SubtreeElements(treeNode x);
295 /** IsLeaf(x): returns whether node x is leaf or not. In the succinct
296 * representation this is just a bit inspection. */
298 bool IsLeaf(treeNode x);
300 /** IsAncestor(x,y): returns whether node x is ancestor of node y. */
302 bool IsAncestor(treeNode x, treeNode y);
304 /** IsChild(x,y): returns whether node x is parent of node y. */
305 bool IsChild(treeNode x, treeNode y);
307 /** IsFirstChild(x): returns whether node x is the first child of its parent. */
309 bool IsFirstChild(treeNode x) {
310 return ((x != NULLT)&&(x==Root() || prev_sibling(Par,x) == (treeNode)-1));
313 /** NumChildren(x): number of children of node x. Constant time with the
314 * data structure of Sadakane. */
315 int NumChildren(treeNode x);
317 /** ChildNumber(x): returns i if node x is the i-th children of its
319 int ChildNumber(treeNode x);
321 /** Depth(x): depth of node x, a simple binary rank on the parentheses
323 int Depth(treeNode x);
325 /** Preorder(x): returns the preorder number of node x, just regarding tree
326 * nodes (and not texts). */
327 int Preorder(treeNode x);
329 /** Postorder(x): returns the postorder number of node x, just regarding
330 * tree nodes (and not texts). */
331 int Postorder(treeNode x);
334 /** DocIds(x): returns the range (i.e., a pair of integers) of document
335 * identifiers that descend from node x. */
336 range DocIds(treeNode x);
338 /** Parent(x): returns the parent node of node x. */
339 treeNode Parent(treeNode x) {
343 return parent(Par, x);
346 treeNode BinaryParent(treeNode x){
350 treeNode prev = x - 1;
351 return (fast_inspect(Par, prev) == OP) ? prev : find_open(Par, prev);
355 /* Assumes x is neither 0 nor -1 */
357 /** Child(x,i): returns the i-th child of node x, assuming it exists. */
358 treeNode Child(treeNode x, int i);
362 /** LastChild(x): returns the last child of node x. */
363 treeNode LastChild(treeNode x) {
364 NULLT_IF(x == NULLT || fast_isleaf(Par,x));
365 return find_open(Par, fast_find_close(Par, x)-1);
368 /** PrevSibling(x): returns the previous sibling of node x, assuming it
371 treeNode PrevSibling(treeNode x)
374 return prev_sibling(Par, x);
378 /** TaggedChild(x,tag): returns the first child of node x tagged tag, or
379 * NULLT if there is none. Because of the balanced-parentheses representation
380 * of the tree, this operation is not supported efficiently, just iterating
381 * among the children of node x until finding the desired child. */
384 treeNode SelectChild(treeNode x, TagIdSet * tags);
386 /** TaggedFollowingSibling(x,tag): returns the first sibling of node x tagged tag, or
387 * NULLT if there is none. */
389 treeNode SelectFollowingSibling(treeNode x, TagIdSet * tags);
394 treeNode SelectDescendant(treeNode x, TagIdSet * tags) {
395 NULLT_IF (x == NULLT);
397 if (fast_inspect(Par, fc) == CP) return NULLT;
398 treeNode min = NULLT;
401 TagIdSet::const_iterator tagit;
402 for (tagit = tags->begin(); tagit != tags->end(); ++tagit) {
403 aux = TaggedDescendant(x, (TagType) *tagit);
404 if (((unsigned int) aux) < ((unsigned int) min)) min = aux;
409 /** TaggedPrec(x,tag): returns the first node tagged tag with smaller
410 * preorder than x and not an ancestor of x. Returns NULLT if there
412 treeNode TaggedPreceding(treeNode x, TagType tag);
414 /** TaggedFoll(x,tag): returns the first node tagged tag with larger
415 * preorder than x and not in the subtree of x. Returns NULLT if there
417 treeNode TaggedFollowing(treeNode x, TagType tag);
421 treeNode SelectFollowingBelow(treeNode x, TagIdSet * tags, treeNode ancestor);
423 // treeNode TaggedFollowingBefore(treeNode x, TagType tag,treeNode closing);
425 treeNode SelectFollowingBefore(treeNode x, TagIdSet * tags, treeNode ancestor_closing)
430 treeNode close = fast_find_close(Par,x);
433 treeNode min = NULLT;
437 TagIdSet::const_iterator tagit;
438 for (tagit = tags->begin(); tagit != tags->end(); ++tagit) {
440 aux = tagpos2node(Tags->select_next(*tagit, close));
442 if (((unsigned int) aux) < ((unsigned int) min)) min = aux;
446 return (min < ancestor_closing) ? min : NULLT;
450 /** TaggedAncestor(x, tag): returns the closest ancestor of x tagged
451 * tag. Return NULLT is there is none. */
452 treeNode TaggedAncestor(treeNode x, TagType tag);
454 /** PrevText(x): returns the document identifier of the text to the left of
455 * node x, or NULLT if x is the root node. */
456 DocID PrevText(treeNode x);
458 /** NextText(x): returns the document identifier of the text to the right of
459 * node x, or NULLT if x is the root node. */
460 DocID NextText(treeNode x);
462 /** MyText(x): returns the document identifier of the text below node x, or
463 * NULLT if x is not a leaf node. */
464 DocID MyText(treeNode x);
465 DocID MyTextUnsafe(treeNode x);
467 /** TextXMLId(d): returns the preorder of document with identifier d in the
468 * tree consisting of all tree nodes and all text nodes. */
469 int TextXMLId(DocID d);
471 /** NodeXMLId(x): returns the preorder of node x in the tree consisting of
472 * all tree nodes and all text nodes. */
473 int NodeXMLId(treeNode x);
475 /** ParentNode(d): returns the parent node of document identifier d. */
476 treeNode ParentNode(DocID d);
478 treeNode PrevNode(DocID d);
480 /** GetTagId(tagname): returns the tag identifier corresponding to a given
481 * tag name. Returns NULLT in case that the tag name does not exists. */
482 TagType GetTagId(unsigned char *tagname);
484 /** GetTagName(tagid): returns the tag name of a given tag identifier.
485 * Returns NULL in case that the tag identifier is not valid.*/
486 unsigned char *GetTagName(TagType tagid);
488 /** GetTagName(tagid): returns the tag name of a given tag identifier.
489 * The result is just a reference and should not be freed by the caller.
491 const unsigned char *GetTagNameByRef(TagType tagid);
493 /** RegisterTag adds a new tag to the tag collection this is needed
494 * if the query contains a tag which is not in the document, we need
495 * to give this new tag a fresh id and store it somewhere. A logical
497 * We might want to use a hashtable instead of an array though.
499 TagType RegisterTag(unsigned char *tagname);
501 bool EmptyText(DocID i) {
502 return Text->EmptyText(i);
505 /** Prefix(s): search for texts prefixed by string s. */
506 TextCollection::document_result Prefix(uchar const *s) {
507 return Text->Prefix(s);
510 /** Suffix(s): search for texts having string s as a suffix. */
511 TextCollection::document_result Suffix(uchar const *s) {
512 return Text->Suffix(s);
515 /** Equal(s): search for texts equal to string s. */
516 TextCollection::document_result Equals(uchar const *s) {
517 return Text->Equal(s);
520 /** Contains(s): search for texts containing string s. */
521 TextCollection::document_result Contains(uchar const *s) {
522 return Text->Contains(s);
525 /** LessThan(s): returns document identifiers for the texts that
526 * are lexicographically smaller than string s. */
527 TextCollection::document_result LessThan(uchar const *s) {
528 return Text->LessThan(s);
531 /** IsPrefix(x): returns true if there is a text prefixed by string s. */
532 bool IsPrefix(uchar const *s) {
533 return Text->IsPrefix(s);
536 /** IsSuffix(s): returns true if there is a text having string s as a
538 bool IsSuffix(uchar const *s) {
539 return Text->IsSuffix(s);
542 /** IsEqual(s): returns true if there is a text that equals given
544 bool IsEqual(uchar const *s) {
545 return Text->IsEqual(s);
548 /** IsContains(s): returns true if there is a text containing string s. */
549 bool IsContains(uchar const *s) {
550 return Text->IsContains(s);
553 /** IsLessThan(s): returns true if there is at least a text that is
554 * lexicographically smaller than string s. */
555 bool IsLessThan(uchar const *s) {
556 return Text->IsLessThan(s);
559 /** Count(s): Global counting */
560 unsigned Count(uchar const *s) {
561 return Text->Count(s);
564 /** CountPrefix(s): counting version of Prefix(s). */
565 unsigned CountPrefix(uchar const *s) {
566 return Text->CountPrefix(s);
569 /** CountSuffix(s): counting version of Suffix(s). */
570 unsigned CountSuffix(uchar const *s) {
571 return Text->CountSuffix(s);
574 /** CountEqual(s): counting version of Equal(s). */
575 unsigned CountEqual(uchar const *s) {
576 return Text->CountEqual(s);
579 /** CountContains(s): counting version of Contains(s). */
580 unsigned CountContains(uchar const *s) {
581 return Text->CountContains(s);
584 /** CountLessThan(s): counting version of LessThan(s). */
585 unsigned CountLessThan(uchar const *s) {
586 return Text->CountLessThan(s);
589 /** GetText(d): returns the text corresponding to document with
591 uchar* GetText(DocID d) {
593 uchar * s = Text->GetText(d);
594 return (s[0] == 1 ? (s+1) : s);
597 /** GetText(i, j): returns the texts corresponding to documents with
598 * ids i, i+1, ..., j. Texts are separated by '\0' character. */
599 // uchar* GetText(DocID i, DocID j) {
600 // uchar * s = Text->GetText(i, j);
601 // return (s[0] == 1 ? (uchar*)"" : s);
604 TextCollection *getTextCollection() {
608 /** Save: saves XML tree data structure to file. */
611 /** Load: loads XML tree data structure from file. sample_rate_text
612 * indicates the sample rate for the text search data structure. */
613 static XMLTree *Load(int fd, bool load_tc, int sample_factor);
615 void insertTag(TagType tag, uint position);
620 /** Parenthesis functions */
621 treeNode Closing(treeNode x);
623 bool IsOpen(treeNode x);
626 /** Print procedure */
627 void Print(int fd,treeNode x, bool no_text);
628 void Print(int fd,treeNode x) { Print(fd,x,false); }
629 void Flush(int fd){ _flush(fd); }
631 // The following are inlined here for speed
632 /** Tag(x): returns the tag identifier of node x. */
634 inline TagType Tag(treeNode x) const throw () {
636 return (TagType) (((uchar*)tags_fix)[(int) x]);
638 return get_field(tags_fix, tags_blen, x);
641 size_t idxlen = x * tags_blen;
642 size_t j = idxlen % W;
643 size_t i = idxlen / W;
644 size_t offset = W - tags_blen;
645 size_t offset2 = offset - j;
646 size_t w = tags_fix[i];
647 return (offset2 >= 0)
648 ? ( w << offset2 ) >> offset
649 : ( w >> j) | (tags_fix[i+1] << (W+offset2)) >> offset;
654 /** FirstChild(x): returns the first child of node x, or NULLT if the node is a leaf
656 treeNode FirstChild(treeNode x) {
658 return fast_first_child(Par, x);
662 /** FirstElement(x): returns the first non text, non attribute child of node x, or NULLT
665 treeNode FirstElement(treeNode node){
667 NULLT_IF(node == NULLT);
668 treeNode x = fast_first_child(Par, node);
669 NULLT_IF(x == NULLT);
672 case ATTRIBUTE_TAG_ID:
673 x = fast_next_sibling(Par,x);
674 if (x == NULLT || Tag(x) != PCDATA_TAG_ID) return x;
678 return (fast_inspect(Par,x)==OP)? x : NULLT;
686 /** NextSibling(x): returns the next sibling of node x, or NULLT if none
689 treeNode NextSibling(treeNode x) {
691 return fast_next_sibling(Par, x);
694 /** NextElement(x): returns the first non text, non attribute sibling of node x, or NULLT
697 treeNode NextElement(treeNode x)
700 x = fast_next_sibling(Par, x);
701 NULLT_IF(x == NULLT);
702 if (Tag(x) == PCDATA_TAG_ID){
704 return (fast_inspect(Par, y) == OP) ? y : NULLT;
708 /** TaggedDesc(x,tag): returns the first node tagged tag with larger
709 * preorder than x and within the subtree of x. Returns NULT if there
711 inline treeNode TaggedDescendant(treeNode x, TagType tag)
714 int s = (int) Tags->select_next(tag,node2tagpos(x));
717 treeNode y = tagpos2node(s); // transforms the tag position into a node position
719 return (fast_is_ancestor(Par,x,y) ? y : NULLT);
722 inline treeNode TaggedFollowingBelow(treeNode x, TagType tag, treeNode ancestor)
724 treeNode close = fast_find_close(Par, x);
725 treeNode s = tagpos2node(Tags->select_next(tag, close));
727 if (ancestor == Root() || s == NULLT || s < fast_find_close(Par,ancestor)) return s;
731 inline treeNode TaggedFollowingBefore(treeNode x, TagType tag, treeNode ancestor_closing)
733 treeNode close = fast_find_close(Par, x);
734 treeNode s = tagpos2node(Tags->select_next(tag, close));
736 if (ancestor_closing == Root() || s == NULLT || s < ancestor_closing) return s;
740 // TaggedSibling(x,tag): returns the first sibling of node x tagged tag, or NULLT if there is none.
741 treeNode TaggedFollowingSibling(treeNode x, TagType tag)
744 treeNode sibling = x;
746 while ((sibling = fast_next_sibling(Par, sibling)) != NULLT) {
748 if (ctag == tag) return sibling;
753 treeNode TaggedChild(treeNode x, TagType tag)
756 NULLT_IF(x==NULLT || fast_isleaf(Par,x));
758 child = fast_first_child(Par, x);
760 if (Tag(child) == tag)
763 return TaggedFollowingSibling(child, tag);