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 <libcds/includes/static_bitsequence.h>
37 #include <libcds/includes/alphabet_mapper.h>
38 #include <libcds/includes/static_sequence.h>
40 using SXSI::TextCollection;
41 using SXSI::TextCollectionBuilder;
44 // this constant is used to efficiently compute the child operation in the tree
49 #define PERM_SAMPLE 10
61 // Encoding of the XML Document :
62 // The following TAGs and IDs are fixed, "" is the tag of the root.
63 // a TextNode is represented by a leaf <<$>></<$>> The DocId in the TextCollection
64 // of that leaf is kept in a bit sequence.
65 // a TextNode below an attribute is likewise represented by a leaf <<@$>><</@$>>
66 // An element <e a1="v1" a2="v2" ... an="vn" > ...</e> the representation is:
67 // <e><<@>> <<@>a1> <<$@>>DocID(v1)</<$@>></<@>a1> ... </<@>> .... </e>
68 // Hence the attributes (if any) are always below the first child of their element,
69 // as the children of a fake node <@>.
72 #define DOCUMENT_OPEN_TAG ""
73 #define DOCUMENT_TAG_ID 0
74 #define ATTRIBUTE_OPEN_TAG "<@>"
75 #define ATTRIBUTE_TAG_ID 1
76 #define PCDATA_OPEN_TAG "<$>"
77 #define PCDATA_TAG_ID 2
78 #define ATTRIBUTE_DATA_OPEN_TAG "<@$>"
79 #define ATTRIBUTE_DATA_TAG_ID 3
80 #define CLOSING_TAG "</>"
81 #define CLOSING_TAG_ID 4
82 #define DOCUMENT_CLOSE_TAG "/"
83 #define ATTRIBUTE_CLOSE_TAG "/<@>"
84 #define PCDATA_CLOSE_TAG "/<$>"
85 #define ATTRIBUTE_DATA_CLOSE_TAG "/<@$>"
88 typedef std::unordered_set<int> TagIdSet;
89 typedef std::unordered_map<std::string,int> TagIdMap;
90 typedef TagIdMap::const_iterator TagIdMapIT;
92 #define REGISTER_TAG(v,h,t) do { (h)->insert(std::make_pair((t),(v)->size()));\
93 (v)->push_back(t); } while (false)
95 // returns NULLT if the test is true
96 #define NULLT_IF(x) do { if (x) return NULLT; } while (0)
98 // Direct calls to sarray library
100 #define BUFFER_ALLOC (8192 * 2)
101 #define BUFFER_SIZE (BUFFER_ALLOC / 2)
102 static inline int fast_find_open(bp *b,int s)
105 r = bwd_excess(b,s,0);
106 if (r >= -1) return r+1;
110 static inline int fast_find_close(bp *b,int s)
112 return fwd_excess(b,s,-1);
115 static inline int fast_find_parent_close(bp *b,int s)
117 return fwd_excess(b,s,-2);
121 static inline int fast_inspect(bp* Par,treeNode i)
126 return (Par->B[j] >> (D-1-l)) & 1;
129 static bool fast_isleaf(bp* Par,treeNode x){
130 return (fast_inspect(Par, x+1) == CP);
133 static treeNode fast_first_child(bp *Par, treeNode x)
136 return (fast_inspect(Par,x) == OP) ? x : NULLT;
139 inline static treeNode fast_next_sibling(bp* Par,treeNode x)
141 treeNode y = fast_find_close(Par,x)+1;
142 return (fast_inspect(Par, y) == OP) ? y : NULLT;
145 inline static bool fast_is_ancestor(bp * Par,treeNode x,treeNode y){
146 return (x <= y) && ((x==0) || (y <= fast_find_close(Par,x)));
149 // tag position -> tree node
150 static treeNode tagpos2node(int t)
154 // tree node -> tag position
155 static int node2tagpos(treeNode x)
161 class XMLTreeBuilder;
165 // Only the builder can access the constructor
166 friend class XMLTreeBuilder;
169 /** Balanced parentheses representation of the tree */
172 /** Mapping from tag identifer to tag name */
173 std::vector<std::string> *TagName;
176 /** Bit vector indicating with a 1 the positions of the non-empty texts. */
177 static_bitsequence *EBVector;
179 /** Tag sequence represented with a data structure for rank and select */
180 static_sequence *Tags;
182 uint tags_blen, tags_len;
184 /** The texts in the XML document */
185 TextCollection *Text;
187 // Allows to disable the TextCollection for benchmarkin purposes
189 SXSI::TextCollectionBuilder::index_type_t text_index_type;
192 std::vector<std::string *> *print_stack;
195 void _real_flush(int fd, size_t size) {
196 if (size == 0) return;
199 written = write(fd, buffer->data(), size);
200 if ((written < 0) && (errno == EAGAIN || errno == EINTR))
209 size_t size = buffer->size();
210 if (size < BUFFER_SIZE) return;
211 _real_flush(fd, size);
214 void _dput_str(std::string s, int fd){
219 void _dputs(const char* s, int fd){
224 void _dputc(const char c, int fd){
225 buffer->push_back(c);
228 size_t _dprintf(const char* s, int fd){
229 if (s == NULL) return 0;
232 for (i = 0; (c = s[i]); i++) {
235 _dputs(""", fd);
241 _dputs("'", fd);
257 void PrintNode(treeNode n, int fd);
258 /** Data structure constructors */
259 XMLTree(){ buffer = 0;};
261 // non const pointer are freed by this method.
262 XMLTree( pb * const par,
264 std::vector<std::string> * const TN,
265 TagIdMap * const tim, uint *empty_texts_bmp,
267 TextCollection * const TC, bool dis_tc,
268 TextCollectionBuilder::index_type_t _index_type );
271 /** Data structure destructor */
274 /** root(): returns the tree root. */
275 treeNode Root() { return 0; }
277 /** Size() : Number of parenthesis */
283 /** NumTags() : Number of distinct tags */
284 unsigned int NumTags() {
285 return TagName->size();
288 int TagsBinaryLength(){ return tags_blen; };
289 unsigned int TagStructLength(){ return uint_len(tags_blen,tags_len); };
290 unsigned int * TagStruct() { return tags_fix; };
293 /** SubtreeSize(x): the number of nodes (and attributes) in the subtree of
295 int SubtreeSize(treeNode x) { return subtree_size(Par, x); }
297 /** SubtreeTags(x,tag): the number of occurrences of tag within the subtree
299 int SubtreeTags(treeNode x, TagType tag){
300 //int s = x + 2*subtree_size(Par, x) - 1;
301 treeNode y = fast_find_close(Par, x);
305 for(int i = x; i < y; i++)
306 count += (Tag(i) == tag);
310 return (Tags->rank(tag, y) - Tags->rank(tag, x));
313 /** SubtreeElements(x) of element nodes in the subtree of x
315 int SubtreeElements(treeNode x);
317 /** IsLeaf(x): returns whether node x is leaf or not. In the succinct
318 * representation this is just a bit inspection. */
320 bool IsLeaf(treeNode x);
322 /** IsAncestor(x,y): returns whether node x is ancestor of node y. */
324 bool IsAncestor(treeNode x, treeNode y);
327 /** IsRigthDescendant returns true if y is a descendant of x and y is
328 not a descendant of the first child of x */
329 bool IsRightDescendant(treeNode x, treeNode y) {
330 if (x <= Root()) return false;
331 treeNode z = fast_find_parent_close(Par, x);
332 treeNode c = fast_find_close(Par, x);
333 return (y > c && y < z );
337 /** IsChild(x,y): returns whether node x is parent of node y. */
338 bool IsChild(treeNode x, treeNode y);
340 /** IsFirstChild(x): returns whether node x is the first child of its parent. */
342 bool IsFirstChild(treeNode x) {
343 return ((x != NULLT)&&(x==Root() || prev_sibling(Par,x) == (treeNode)-1));
346 /** NumChildren(x): number of children of node x. Constant time with the
347 * data structure of Sadakane. */
348 int NumChildren(treeNode x);
350 /** ChildNumber(x): returns i if node x is the i-th children of its
352 int ChildNumber(treeNode x);
354 /** Depth(x): depth of node x, a simple binary rank on the parentheses
356 int Depth(treeNode x);
358 /** Preorder(x): returns the preorder number of node x, just regarding tree
359 * nodes (and not texts). */
360 int Preorder(treeNode x);
362 /** Postorder(x): returns the postorder number of node x, just regarding
363 * tree nodes (and not texts). */
364 int Postorder(treeNode x);
367 /** DocIds(x): returns the range (i.e., a pair of integers) of document
368 * identifiers that descend from node x. */
369 range DocIds(treeNode x);
371 /** Parent(x): returns the parent node of node x. */
372 treeNode Parent(treeNode x) {
376 return parent(Par, x);
379 treeNode BinaryParent(treeNode x){
383 treeNode prev = x - 1;
384 return (fast_inspect(Par, prev) == OP) ? prev : fast_find_open(Par, prev);
388 /* Assumes x is neither 0 nor -1 */
390 /** Child(x,i): returns the i-th child of node x, assuming it exists. */
391 treeNode Child(treeNode x, int i);
395 /** LastChild(x): returns the last child of node x. */
396 treeNode LastChild(treeNode x) {
397 NULLT_IF(x == NULLT || fast_isleaf(Par,x));
398 return fast_find_open(Par, fast_find_close(Par, x)-1);
401 /** PrevSibling(x): returns the previous sibling of node x, assuming it
404 treeNode PrevSibling(treeNode x)
407 return prev_sibling(Par, x);
411 /** TaggedChild(x,tag): returns the first child of node x tagged tag, or
412 * NULLT if there is none. Because of the balanced-parentheses representation
413 * of the tree, this operation is not supported efficiently, just iterating
414 * among the children of node x until finding the desired child. */
417 treeNode SelectChild(treeNode x, TagIdSet * tags);
419 /** TaggedFollowingSibling(x,tag): returns the first sibling of node x tagged tag, or
420 * NULLT if there is none. */
422 treeNode SelectFollowingSibling(treeNode x, TagIdSet * tags);
427 treeNode SelectDescendant(treeNode x, TagIdSet * tags) {
428 NULLT_IF (x == NULLT);
430 if (fast_inspect(Par, fc) == CP) return NULLT;
431 treeNode min = NULLT;
434 TagIdSet::const_iterator tagit;
435 for (tagit = tags->begin(); tagit != tags->end(); ++tagit) {
436 aux = TaggedDescendant(x, (TagType) *tagit);
437 if (((unsigned int) aux) < ((unsigned int) min)) min = aux;
442 /** TaggedPrec(x,tag): returns the first node tagged tag with smaller
443 * preorder than x and not an ancestor of x. Returns NULLT if there
445 treeNode TaggedPreceding(treeNode x, TagType tag);
447 /** TaggedFoll(x,tag): returns the first node tagged tag with larger
448 * preorder than x and not in the subtree of x. Returns NULLT if there
450 treeNode TaggedFollowing(treeNode x, TagType tag);
454 treeNode SelectFollowingBelow(treeNode x, TagIdSet * tags, treeNode ancestor);
456 // treeNode TaggedFollowingBefore(treeNode x, TagType tag,treeNode closing);
458 treeNode SelectFollowingBefore(treeNode x, TagIdSet * tags, treeNode ancestor_closing)
463 treeNode close = fast_find_close(Par,x);
466 treeNode min = NULLT;
470 TagIdSet::const_iterator tagit;
471 for (tagit = tags->begin(); tagit != tags->end(); ++tagit) {
473 aux = tagpos2node(Tags->select_next(*tagit, close));
475 if (((unsigned int) aux) < ((unsigned int) min)) min = aux;
479 return (min < ancestor_closing) ? min : NULLT;
483 /** TaggedAncestor(x, tag): returns the closest ancestor of x tagged
484 * tag. Return NULLT is there is none. */
485 treeNode TaggedAncestor(treeNode x, TagType tag);
487 /** PrevText(x): returns the document identifier of the text to the left of
488 * node x, or NULLT if x is the root node. */
489 DocID PrevText(treeNode x);
491 /** NextText(x): returns the document identifier of the text to the right of
492 * node x, or NULLT if x is the root node. */
493 DocID NextText(treeNode x);
495 /** MyText(x): returns the document identifier of the text below node x, or
496 * NULLT if x is not a leaf node. */
497 DocID MyText(treeNode x);
498 DocID MyTextUnsafe(treeNode x);
500 /** TextXMLId(d): returns the preorder of document with identifier d in the
501 * tree consisting of all tree nodes and all text nodes. */
502 int TextXMLId(DocID d);
504 /** NodeXMLId(x): returns the preorder of node x in the tree consisting of
505 * all tree nodes and all text nodes. */
506 int NodeXMLId(treeNode x);
508 /** ParentNode(d): returns the parent node of document identifier d. */
509 treeNode ParentNode(DocID d);
511 treeNode PrevNode(DocID d);
513 /** GetTagId(tagname): returns the tag identifier corresponding to a given
514 * tag name. Returns NULLT in case that the tag name does not exists. */
515 TagType GetTagId(unsigned char *tagname);
517 /** GetTagName(tagid): returns the tag name of a given tag identifier.
518 * Returns NULL in case that the tag identifier is not valid.*/
519 unsigned char *GetTagName(TagType tagid);
521 /** GetTagName(tagid): returns the tag name of a given tag identifier.
522 * The result is just a reference and should not be freed by the caller.
524 const unsigned char *GetTagNameByRef(TagType tagid);
526 /** RegisterTag adds a new tag to the tag collection this is needed
527 * if the query contains a tag which is not in the document, we need
528 * to give this new tag a fresh id and store it somewhere. A logical
530 * We might want to use a hashtable instead of an array though.
532 TagType RegisterTag(unsigned char *tagname);
534 bool EmptyText(DocID i) {
535 return Text->EmptyText(i);
538 /** Prefix(s): search for texts prefixed by string s. */
539 TextCollection::document_result Prefix(uchar const *s) {
540 return Text->Prefix(s);
543 /** Suffix(s): search for texts having string s as a suffix. */
544 TextCollection::document_result Suffix(uchar const *s) {
545 return Text->Suffix(s);
548 /** Equal(s): search for texts equal to string s. */
549 TextCollection::document_result Equals(uchar const *s) {
550 return Text->Equal(s);
553 /** Contains(s): search for texts containing string s. */
554 TextCollection::document_result Contains(uchar const *s) {
555 return Text->Contains(s);
558 /** LessThan(s): returns document identifiers for the texts that
559 * are lexicographically smaller than string s. */
560 TextCollection::document_result LessThan(uchar const *s) {
561 return Text->LessThan(s);
564 /** IsPrefix(x): returns true if there is a text prefixed by string s. */
565 bool IsPrefix(uchar const *s) {
566 return Text->IsPrefix(s);
569 /** IsSuffix(s): returns true if there is a text having string s as a
571 bool IsSuffix(uchar const *s) {
572 return Text->IsSuffix(s);
575 /** IsEqual(s): returns true if there is a text that equals given
577 bool IsEqual(uchar const *s) {
578 return Text->IsEqual(s);
581 /** IsContains(s): returns true if there is a text containing string s. */
582 bool IsContains(uchar const *s) {
583 return Text->IsContains(s);
586 /** IsLessThan(s): returns true if there is at least a text that is
587 * lexicographically smaller than string s. */
588 bool IsLessThan(uchar const *s) {
589 return Text->IsLessThan(s);
592 /** Count(s): Global counting */
593 unsigned Count(uchar const *s) {
594 return Text->Count(s);
597 /** CountPrefix(s): counting version of Prefix(s). */
598 unsigned CountPrefix(uchar const *s) {
599 return Text->CountPrefix(s);
602 /** CountSuffix(s): counting version of Suffix(s). */
603 unsigned CountSuffix(uchar const *s) {
604 return Text->CountSuffix(s);
607 /** CountEqual(s): counting version of Equal(s). */
608 unsigned CountEqual(uchar const *s) {
609 return Text->CountEqual(s);
612 /** CountContains(s): counting version of Contains(s). */
613 unsigned CountContains(uchar const *s) {
614 return Text->CountContains(s);
617 /** CountLessThan(s): counting version of LessThan(s). */
618 unsigned CountLessThan(uchar const *s) {
619 return Text->CountLessThan(s);
622 /** GetText(d): returns the text corresponding to document with
624 uchar* GetText(DocID d) {
626 uchar * s = Text->GetText(d);
627 return (s[0] == 1 ? (s+1) : s);
630 /** GetText(i, j): returns the texts corresponding to documents with
631 * ids i, i+1, ..., j. Texts are separated by '\0' character. */
632 // uchar* GetText(DocID i, DocID j) {
633 // uchar * s = Text->GetText(i, j);
634 // return (s[0] == 1 ? (uchar*)"" : s);
637 TextCollection *getTextCollection() {
641 /** Save: saves XML tree data structure to file. */
642 void Save(int fd, char* name );
644 /** Load: loads XML tree data structure from file. sample_rate_text
645 * indicates the sample rate for the text search data structure. */
646 static XMLTree *Load(int fd, bool load_tc, int sample_factor, char * name);
648 void insertTag(TagType tag, uint position);
653 /** Parenthesis functions */
654 treeNode Closing(treeNode x);
656 bool IsOpen(treeNode x);
659 /** Print procedure */
660 void Print(int fd,treeNode x, bool no_text);
661 void Print(int fd,treeNode x) { Print(fd,x,false); }
662 void Flush(int fd){ if (buffer) _real_flush(fd, buffer->size()); }
664 // The following are inlined here for speed
665 /** Tag(x): returns the tag identifier of node x. */
667 inline TagType Tag(treeNode x) const throw () {
669 return (TagType) (((uchar*)tags_fix)[(int) x]);
671 return get_field(tags_fix, tags_blen, x);
674 size_t idxlen = x * tags_blen;
675 size_t j = idxlen % W;
676 size_t i = idxlen / W;
677 size_t offset = W - tags_blen;
678 size_t offset2 = offset - j;
679 size_t w = tags_fix[i];
680 return (offset2 >= 0)
681 ? ( w << offset2 ) >> offset
682 : ( w >> j) | (tags_fix[i+1] << (W+offset2)) >> offset;
687 /** FirstChild(x): returns the first child of node x, or NULLT if the node is a leaf
689 treeNode FirstChild(treeNode x) {
691 return fast_first_child(Par, x);
695 /** FirstElement(x): returns the first non text, non attribute child of node x, or NULLT
698 treeNode FirstElement(treeNode node){
700 NULLT_IF(node == NULLT);
701 treeNode x = fast_first_child(Par, node);
702 NULLT_IF(x == NULLT);
705 case ATTRIBUTE_TAG_ID:
706 x = fast_next_sibling(Par,x);
707 if (x == NULLT || Tag(x) != PCDATA_TAG_ID) return x;
711 return (fast_inspect(Par,x)==OP)? x : NULLT;
719 /** NextSibling(x): returns the next sibling of node x, or NULLT if none
722 treeNode NextSibling(treeNode x) {
724 return fast_next_sibling(Par, x);
727 /** NextElement(x): returns the first non text, non attribute sibling of node x, or NULLT
730 treeNode NextElement(treeNode x)
733 x = fast_next_sibling(Par, x);
734 NULLT_IF(x == NULLT);
735 if (Tag(x) == PCDATA_TAG_ID){
737 return (fast_inspect(Par, y) == OP) ? y : NULLT;
741 /** TaggedDesc(x,tag): returns the first node tagged tag with larger
742 * preorder than x and within the subtree of x. Returns NULT if there
744 inline treeNode TaggedNext(treeNode x, TagType tag)
746 return tagpos2node(Tags->select_next(tag,node2tagpos(x)));
748 inline treeNode TaggedDescendant(treeNode x, TagType tag)
751 int s = (int) Tags->select_next(tag,node2tagpos(x));
754 treeNode y = tagpos2node(s); // transforms the tag position into a node position
756 return (fast_is_ancestor(Par,x,y) ? y : NULLT);
759 inline treeNode TaggedFollowingBelow(treeNode x, TagType tag, treeNode ancestor)
761 treeNode close = fast_find_close(Par, x);
762 treeNode s = tagpos2node(Tags->select_next(tag, close));
764 if (ancestor == Root() || s == NULLT || s < fast_find_close(Par,ancestor)) return s;
768 inline treeNode TaggedFollowingBefore(treeNode x, TagType tag, treeNode ancestor_closing)
770 treeNode close = fast_find_close(Par, x);
771 treeNode s = tagpos2node(Tags->select_next(tag, close));
773 if (ancestor_closing == Root() || s == NULLT || s < ancestor_closing) return s;
777 inline treeNode NextNodeBefore(treeNode x, treeNode ancestor_closing)
779 treeNode close = fast_find_close(Par, x);
780 int rank = rank_open(Par, close);
781 treeNode y = select_open(Par, rank+1);
782 return (y < ancestor_closing) ? y : NULLT;
785 // TaggedSibling(x,tag): returns the first sibling of node x tagged tag, or NULLT if there is none.
786 treeNode TaggedFollowingSibling(treeNode x, TagType tag)
789 treeNode sibling = x;
791 while ((sibling = fast_next_sibling(Par, sibling)) != NULLT) {
793 if (ctag == tag) return sibling;
798 treeNode TaggedChild(treeNode x, TagType tag)
801 NULLT_IF(x==NULLT || fast_isleaf(Par,x));
803 child = fast_first_child(Par, x);
805 if (Tag(child) == tag)
808 return TaggedFollowingSibling(child, tag);