| /* |
| ** 2012 April 10 |
| ** |
| ** The author disclaims copyright to this source code. In place of |
| ** a legal notice, here is a blessing: |
| ** |
| ** May you do good and not evil. |
| ** May you find forgiveness for yourself and forgive others. |
| ** May you share freely, never taking more than you give. |
| ** |
| ************************************************************************* |
| ** |
| ** This module implements a VIRTUAL TABLE that can be used to search |
| ** a large vocabulary for close matches. For example, this virtual |
| ** table can be used to suggest corrections to misspelled words. Or, |
| ** it could be used with FTS4 to do full-text search using potentially |
| ** misspelled words. |
| ** |
| ** Create an instance of the virtual table this way: |
| ** |
| ** CREATE VIRTUAL TABLE demo USING spellfix1; |
| ** |
| ** The "spellfix1" term is the name of this module. The "demo" is the |
| ** name of the virtual table you will be creating. The table is initially |
| ** empty. You have to populate it with your vocabulary. Suppose you |
| ** have a list of words in a table named "big_vocabulary". Then do this: |
| ** |
| ** INSERT INTO demo(word) SELECT word FROM big_vocabulary; |
| ** |
| ** If you intend to use this virtual table in cooperation with an FTS4 |
| ** table (for spelling correctly of search terms) then you can extract |
| ** the vocabulary using an fts3aux table: |
| ** |
| ** INSERT INTO demo(word) SELECT term FROM search_aux WHERE col='*'; |
| ** |
| ** You can also provide the virtual table with a "rank" for each word. |
| ** The "rank" is an estimate of how common the word is. Larger numbers |
| ** mean the word is more common. If you omit the rank when populating |
| ** the table, then a rank of 1 is assumed. But if you have rank |
| ** information, you can supply it and the virtual table will show a |
| ** slight preference for selecting more commonly used terms. To |
| ** populate the rank from an fts4aux table "search_aux" do something |
| ** like this: |
| ** |
| ** INSERT INTO demo(word,rank) |
| ** SELECT term, documents FROM search_aux WHERE col='*'; |
| ** |
| ** To query the virtual table, include a MATCH operator in the WHERE |
| ** clause. For example: |
| ** |
| ** SELECT word FROM demo WHERE word MATCH 'kennasaw'; |
| ** |
| ** Using a dataset of American place names (derived from |
| ** http://geonames.usgs.gov/domestic/download_data.htm) the query above |
| ** returns 20 results beginning with: |
| ** |
| ** kennesaw |
| ** kenosha |
| ** kenesaw |
| ** kenaga |
| ** keanak |
| ** |
| ** If you append the character '*' to the end of the pattern, then |
| ** a prefix search is performed. For example: |
| ** |
| ** SELECT word FROM demo WHERE word MATCH 'kennes*'; |
| ** |
| ** Yields 20 results beginning with: |
| ** |
| ** kennesaw |
| ** kennestone |
| ** kenneson |
| ** kenneys |
| ** keanes |
| ** keenes |
| ** |
| ** The virtual table actually has a unique rowid with five columns plus three |
| ** extra hidden columns. The columns are as follows: |
| ** |
| ** rowid A unique integer number associated with each |
| ** vocabulary item in the table. This can be used |
| ** as a foreign key on other tables in the database. |
| ** |
| ** word The text of the word that matches the pattern. |
| ** Both word and pattern can contains unicode characters |
| ** and can be mixed case. |
| ** |
| ** rank This is the rank of the word, as specified in the |
| ** original INSERT statement. |
| ** |
| ** distance This is an edit distance or Levensthein distance going |
| ** from the pattern to the word. |
| ** |
| ** langid This is the language-id of the word. All queries are |
| ** against a single language-id, which defaults to 0. |
| ** For any given query this value is the same on all rows. |
| ** |
| ** score The score is a combination of rank and distance. The |
| ** idea is that a lower score is better. The virtual table |
| ** attempts to find words with the lowest score and |
| ** by default (unless overridden by ORDER BY) returns |
| ** results in order of increasing score. |
| ** |
| ** top (HIDDEN) For any query, this value is the same on all |
| ** rows. It is an integer which is the maximum number of |
| ** rows that will be output. The actually number of rows |
| ** output might be less than this number, but it will never |
| ** be greater. The default value for top is 20, but that |
| ** can be changed for each query by including a term of |
| ** the form "top=N" in the WHERE clause of the query. |
| ** |
| ** scope (HIDDEN) For any query, this value is the same on all |
| ** rows. The scope is a measure of how widely the virtual |
| ** table looks for matching words. Smaller values of |
| ** scope cause a broader search. The scope is normally |
| ** choosen automatically and is capped at 4. Applications |
| ** can change the scope by including a term of the form |
| ** "scope=N" in the WHERE clause of the query. Increasing |
| ** the scope will make the query run faster, but will reduce |
| ** the possible corrections. |
| ** |
| ** srchcnt (HIDDEN) For any query, this value is the same on all |
| ** rows. This value is an integer which is the number of |
| ** of words examined using the edit-distance algorithm to |
| ** find the top matches that are ultimately displayed. This |
| ** value is for diagnostic use only. |
| ** |
| ** soundslike (HIDDEN) When inserting vocabulary entries, this field |
| ** can be set to an spelling that matches what the word |
| ** sounds like. See the DEALING WITH UNUSUAL AND DIFFICULT |
| ** SPELLINGS section below for details. |
| ** |
| ** When inserting into or updating the virtual table, only the rowid, word, |
| ** rank, and langid may be changes. Any attempt to set or modify the values |
| ** of distance, score, top, scope, or srchcnt is silently ignored. |
| ** |
| ** ALGORITHM |
| ** |
| ** A shadow table named "%_vocab" (where the % is replaced by the name of |
| ** the virtual table; Ex: "demo_vocab" for the "demo" virtual table) is |
| ** constructed with these columns: |
| ** |
| ** id The unique id (INTEGER PRIMARY KEY) |
| ** |
| ** rank The rank of word. |
| ** |
| ** langid The language id for this entry. |
| ** |
| ** word The original UTF8 text of the vocabulary word |
| ** |
| ** k1 The word transliterated into lower-case ASCII. |
| ** There is a standard table of mappings from non-ASCII |
| ** characters into ASCII. Examples: "æ" -> "ae", |
| ** "þ" -> "th", "ß" -> "ss", "á" -> "a", ... The |
| ** accessory function spellfix1_translit(X) will do |
| ** the non-ASCII to ASCII mapping. The built-in lower(X) |
| ** function will convert to lower-case. Thus: |
| ** k1 = lower(spellfix1_translit(word)). |
| ** |
| ** k2 This field holds a phonetic code derived from k1. Letters |
| ** that have similar sounds are mapped into the same symbol. |
| ** For example, all vowels and vowel clusters become the |
| ** single symbol "A". And the letters "p", "b", "f", and |
| ** "v" all become "B". All nasal sounds are represented |
| ** as "N". And so forth. The mapping is base on |
| ** ideas found in Soundex, Metaphone, and other |
| ** long-standing phonetic matching systems. This key can |
| ** be generated by the function spellfix1_charclass(X). |
| ** Hence: k2 = spellfix1_charclass(k1) |
| ** |
| ** There is also a function for computing the Wagner edit distance or the |
| ** Levenshtein distance between a pattern and a word. This function |
| ** is exposed as spellfix1_editdist(X,Y). The edit distance function |
| ** returns the "cost" of converting X into Y. Some transformations |
| ** cost more than others. Changing one vowel into a different vowel, |
| ** for example is relatively cheap, as is doubling a constant, or |
| ** omitting the second character of a double-constant. Other transformations |
| ** or more expensive. The idea is that the edit distance function returns |
| ** a low cost of words that are similar and a higher cost for words |
| ** that are futher apart. In this implementation, the maximum cost |
| ** of any single-character edit (delete, insert, or substitute) is 100, |
| ** with lower costs for some edits (such as transforming vowels). |
| ** |
| ** The "score" for a comparison is the edit distance between the pattern |
| ** and the word, adjusted down by the base-2 logorithm of the word rank. |
| ** For example, a match with distance 100 but rank 1000 would have a |
| ** score of 122 (= 100 - log2(1000) + 32) where as a match with distance |
| ** 100 with a rank of 1 would have a score of 131 (100 - log2(1) + 32). |
| ** (NB: The constant 32 is added to each score to keep it from going |
| ** negative in case the edit distance is zero.) In this way, frequently |
| ** used words get a slightly lower cost which tends to move them toward |
| ** the top of the list of alternative spellings. |
| ** |
| ** A straightforward implementation of a spelling corrector would be |
| ** to compare the search term against every word in the vocabulary |
| ** and select the 20 with the lowest scores. However, there will |
| ** typically be hundreds of thousands or millions of words in the |
| ** vocabulary, and so this approach is not fast enough. |
| ** |
| ** Suppose the term that is being spell-corrected is X. To limit |
| ** the search space, X is converted to a k2-like key using the |
| ** equivalent of: |
| ** |
| ** key = spellfix1_charclass(lower(spellfix1_translit(X))) |
| ** |
| ** This key is then limited to "scope" characters. The default scope |
| ** value is 4, but an alternative scope can be specified using the |
| ** "scope=N" term in the WHERE clause. After the key has been truncated, |
| ** the edit distance is run against every term in the vocabulary that |
| ** has a k2 value that begins with the abbreviated key. |
| ** |
| ** For example, suppose the input word is "Paskagula". The phonetic |
| ** key is "BACACALA" which is then truncated to 4 characters "BACA". |
| ** The edit distance is then run on the 4980 entries (out of |
| ** 272,597 entries total) of the vocabulary whose k2 values begin with |
| ** BACA, yielding "Pascagoula" as the best match. |
| ** |
| ** Only terms of the vocabulary with a matching langid are searched. |
| ** Hence, the same table can contain entries from multiple languages |
| ** and only the requested language will be used. The default langid |
| ** is 0. |
| ** |
| ** DEALING WITH UNUSUAL AND DIFFICULT SPELLINGS |
| ** |
| ** The algorithm above works quite well for most cases, but there are |
| ** exceptions. These exceptions can be dealt with by making additional |
| ** entries in the virtual table using the "soundslike" column. |
| ** |
| ** For example, many words of Greek origin begin with letters "ps" where |
| ** the "p" is silent. Ex: psalm, pseudonym, psoriasis, psyche. In |
| ** another example, many Scottish surnames can be spelled with an |
| ** initial "Mac" or "Mc". Thus, "MacKay" and "McKay" are both pronounced |
| ** the same. |
| ** |
| ** Accommodation can be made for words that are not spelled as they |
| ** sound by making additional entries into the virtual table for the |
| ** same word, but adding an alternative spelling in the "soundslike" |
| ** column. For example, the canonical entry for "psalm" would be this: |
| ** |
| ** INSERT INTO demo(word) VALUES('psalm'); |
| ** |
| ** To enhance the ability to correct the spelling of "salm" into |
| ** "psalm", make an addition entry like this: |
| ** |
| ** INSERT INTO demo(word,soundslike) VALUES('psalm','salm'); |
| ** |
| ** It is ok to make multiple entries for the same word as long as |
| ** each entry has a different soundslike value. Note that if no |
| ** soundslike value is specified, the soundslike defaults to the word |
| ** itself. |
| ** |
| ** Listed below are some cases where it might make sense to add additional |
| ** soundslike entries. The specific entries will depend on the application |
| ** and the target language. |
| ** |
| ** * Silent "p" in words beginning with "ps": psalm, psyche |
| ** |
| ** * Silent "p" in words beginning with "pn": pneumonia, pneumatic |
| ** |
| ** * Silent "p" in words beginning with "pt": pterodactyl, ptolemaic |
| ** |
| ** * Silent "d" in words beginning with "dj": djinn, Djikarta |
| ** |
| ** * Silent "k" in words beginning with "kn": knight, Knuthson |
| ** |
| ** * Silent "g" in words beginning with "gn": gnarly, gnome, gnat |
| ** |
| ** * "Mac" versus "Mc" beginning Scottish surnames |
| ** |
| ** * "Tch" sounds in Slavic words: Tchaikovsky vs. Chaykovsky |
| ** |
| ** * The letter "j" pronounced like "h" in Spanish: LaJolla |
| ** |
| ** * Words beginning with "wr" versus "r": write vs. rite |
| ** |
| ** * Miscellanous problem words such as "debt", "tsetse", |
| ** "Nguyen", "Van Nuyes". |
| */ |
| #if SQLITE_CORE |
| # include "sqliteInt.h" |
| #else |
| # include <string.h> |
| # include <stdio.h> |
| # include <stdlib.h> |
| # include "sqlite3ext.h" |
| SQLITE_EXTENSION_INIT1 |
| #endif /* !SQLITE_CORE */ |
| |
| /* |
| ** Character classes for ASCII characters: |
| ** |
| ** 0 '' Silent letters: H W |
| ** 1 'A' Any vowel: A E I O U (Y) |
| ** 2 'B' A bilabeal stop or fricative: B F P V |
| ** 3 'C' Other fricatives or back stops: C G J K Q S X Z |
| ** 4 'D' Alveolar stops: D T |
| ** 5 'H' Letter H at the beginning of a word |
| ** 6 'L' Glides: L R |
| ** 7 'M' Nasals: M N |
| ** 8 'W' Letter W at the beginning of a word |
| ** 9 'Y' Letter Y at the beginning of a word. |
| ** 10 '9' A digit: 0 1 2 3 4 5 6 7 8 9 |
| ** 11 ' ' White space |
| ** 12 '?' Other. |
| */ |
| #define CCLASS_SILENT 0 |
| #define CCLASS_VOWEL 1 |
| #define CCLASS_B 2 |
| #define CCLASS_C 3 |
| #define CCLASS_D 4 |
| #define CCLASS_H 5 |
| #define CCLASS_L 6 |
| #define CCLASS_M 7 |
| #define CCLASS_W 8 |
| #define CCLASS_Y 9 |
| #define CCLASS_DIGIT 10 |
| #define CCLASS_SPACE 11 |
| #define CCLASS_OTHER 12 |
| |
| /* |
| ** The following table gives the character class for non-initial ASCII |
| ** characters. |
| */ |
| static const unsigned char midClass[] = { |
| /* x0 x1 x2 x3 x4 x5 x6 x7 x8 x9 xa xb xc xd xe xf */ |
| /* 0x */ 12, 12, 12, 12, 12, 12, 12, 12, 12, 11, 11, 12, 11, 12, 12, 12, |
| /* 1x */ 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, |
| /* 2x */ 11, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, |
| /* 3x */ 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 12, 12, 12, 12, 12, 12, |
| /* 4x */ 12, 1, 2, 3, 4, 1, 2, 3, 0, 1, 3, 3, 6, 7, 7, 1, |
| /* 5x */ 2, 3, 6, 3, 4, 1, 2, 0, 3, 1, 3, 12, 12, 12, 12, 12, |
| /* 6x */ 12, 1, 2, 3, 4, 1, 2, 3, 0, 1, 3, 3, 6, 7, 7, 1, |
| /* 7x */ 2, 3, 6, 3, 4, 1, 2, 0, 3, 1, 3, 12, 12, 12, 12, 12, |
| }; |
| |
| /* |
| ** This tables gives the character class for ASCII characters that form the |
| ** initial character of a word. The only difference from midClass is with |
| ** the letters H, W, and Y. |
| */ |
| static const unsigned char initClass[] = { |
| /* x0 x1 x2 x3 x4 x5 x6 x7 x8 x9 xa xb xc xd xe xf */ |
| /* 0x */ 12, 12, 12, 12, 12, 12, 12, 12, 12, 11, 11, 12, 11, 12, 12, 12, |
| /* 1x */ 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, |
| /* 2x */ 11, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, |
| /* 3x */ 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 12, 12, 12, 12, 12, 12, |
| /* 4x */ 12, 1, 2, 3, 4, 1, 2, 3, 5, 1, 3, 3, 6, 7, 7, 1, |
| /* 5x */ 2, 3, 6, 3, 4, 1, 2, 8, 3, 9, 3, 12, 12, 12, 12, 12, |
| /* 6x */ 12, 1, 2, 3, 4, 1, 2, 3, 5, 1, 3, 3, 6, 7, 7, 1, |
| /* 7x */ 2, 3, 6, 3, 4, 1, 2, 8, 3, 9, 3, 12, 12, 12, 12, 12, |
| }; |
| |
| /* |
| ** Mapping from the character class number (0-12) to a symbol for each |
| ** character class. Note that initClass[] can be used to map the class |
| ** symbol back into the class number. |
| */ |
| static const unsigned char className[] = ".ABCDHLMWY9 ?"; |
| |
| /* |
| ** Generate a string of character classes corresponding to the |
| ** ASCII characters in the input string zIn. If the input is not |
| ** ASCII then the behavior is undefined. |
| ** |
| ** Space to hold the result is obtained from sqlite3_malloc() |
| ** |
| ** Return NULL if memory allocation fails. |
| */ |
| static unsigned char *characterClassString(const unsigned char *zIn, int nIn){ |
| unsigned char *zOut = sqlite3_malloc( nIn + 1 ); |
| int i; |
| int nOut = 0; |
| char cPrev = 0x77; |
| const unsigned char *aClass = initClass; |
| |
| if( zOut==0 ) return 0; |
| for(i=0; i<nIn; i++){ |
| unsigned char c = zIn[i]; |
| c = aClass[c&0x7f]; |
| if( c==CCLASS_OTHER && cPrev!=CCLASS_DIGIT ) continue; |
| cPrev = c; |
| if( c==CCLASS_SILENT ) continue; |
| if( c==CCLASS_SPACE ) continue; |
| aClass = midClass; |
| c = className[c]; |
| if( c!=zOut[nOut-1] ) zOut[nOut++] = c; |
| } |
| zOut[nOut] = 0; |
| return zOut; |
| } |
| |
| /* |
| ** This is an SQL function wrapper around characterClassString(). See |
| ** the description of characterClassString() for additional information. |
| */ |
| static void characterClassSqlFunc( |
| sqlite3_context *context, |
| int argc, |
| sqlite3_value **argv |
| ){ |
| const unsigned char *zIn; |
| unsigned char *zOut; |
| |
| zIn = sqlite3_value_text(argv[0]); |
| if( zIn==0 ) return; |
| zOut = characterClassString(zIn, sqlite3_value_bytes(argv[0])); |
| if( zOut==0 ){ |
| sqlite3_result_error_nomem(context); |
| }else{ |
| sqlite3_result_text(context, (char*)zOut, -1, sqlite3_free); |
| } |
| } |
| |
| /* |
| ** Return the character class number for a character given its |
| ** context. |
| */ |
| static char characterClass(char cPrev, char c){ |
| return cPrev==0 ? initClass[c&0x7f] : midClass[c&0x7f]; |
| } |
| |
| /* |
| ** Return the cost of inserting or deleting character c immediately |
| ** following character cPrev. If cPrev==0, that means c is the first |
| ** character of the word. |
| */ |
| static int insertOrDeleteCost(char cPrev, char c){ |
| char classC = characterClass(cPrev, c); |
| char classCprev; |
| |
| if( classC==CCLASS_SILENT ){ |
| /* Insert or delete "silent" characters such as H or W */ |
| return 1; |
| } |
| if( cPrev==c ){ |
| /* Repeated characters, or miss a repeat */ |
| return 10; |
| } |
| classCprev = characterClass(cPrev, cPrev); |
| if( classC==classCprev ){ |
| if( classC==CCLASS_VOWEL ){ |
| /* Remove or add a new vowel to a vowel cluster */ |
| return 15; |
| }else{ |
| /* Remove or add a consonant not in the same class */ |
| return 50; |
| } |
| } |
| |
| /* any other character insertion or deletion */ |
| return 100; |
| } |
| |
| /* |
| ** Divide the insertion cost by this factor when appending to the |
| ** end of the word. |
| */ |
| #define FINAL_INS_COST_DIV 4 |
| |
| /* |
| ** Return the cost of substituting cTo in place of cFrom assuming |
| ** the previous character is cPrev. If cPrev==0 then cTo is the first |
| ** character of the word. |
| */ |
| static int substituteCost(char cPrev, char cFrom, char cTo){ |
| char classFrom, classTo; |
| if( cFrom==cTo ){ |
| /* Exact match */ |
| return 0; |
| } |
| if( cFrom==(cTo^0x20) && ((cTo>='A' && cTo<='Z') || (cTo>='a' && cTo<='z')) ){ |
| /* differ only in case */ |
| return 0; |
| } |
| classFrom = characterClass(cPrev, cFrom); |
| classTo = characterClass(cPrev, cTo); |
| if( classFrom==classTo ){ |
| /* Same character class */ |
| return classFrom=='A' ? 25 : 40; |
| } |
| if( classFrom>=CCLASS_B && classFrom<=CCLASS_Y |
| && classTo>=CCLASS_B && classTo<=CCLASS_Y ){ |
| /* Convert from one consonant to another, but in a different class */ |
| return 75; |
| } |
| /* Any other subsitution */ |
| return 100; |
| } |
| |
| /* |
| ** Given two strings zA and zB which are pure ASCII, return the cost |
| ** of transforming zA into zB. If zA ends with '*' assume that it is |
| ** a prefix of zB and give only minimal penalty for extra characters |
| ** on the end of zB. |
| ** |
| ** Smaller numbers mean a closer match. |
| ** |
| ** Negative values indicate an error: |
| ** -1 One of the inputs is NULL |
| ** -2 Non-ASCII characters on input |
| ** -3 Unable to allocate memory |
| */ |
| static int editdist(const char *zA, const char *zB){ |
| int nA, nB; /* Number of characters in zA[] and zB[] */ |
| int xA, xB; /* Loop counters for zA[] and zB[] */ |
| char cA, cB; /* Current character of zA and zB */ |
| char cAprev, cBprev; /* Previous character of zA and zB */ |
| int d; /* North-west cost value */ |
| int dc = 0; /* North-west character value */ |
| int res; /* Final result */ |
| int *m; /* The cost matrix */ |
| char *cx; /* Corresponding character values */ |
| int *toFree = 0; /* Malloced space */ |
| int mStack[60+15]; /* Stack space to use if not too much is needed */ |
| |
| /* Early out if either input is NULL */ |
| if( zA==0 || zB==0 ) return -1; |
| |
| /* Skip any common prefix */ |
| while( zA[0] && zA[0]==zB[0] ){ dc = zA[0]; zA++; zB++; } |
| if( zA[0]==0 && zB[0]==0 ) return 0; |
| |
| #if 0 |
| printf("A=\"%s\" B=\"%s\" dc=%c\n", zA, zB, dc?dc:' '); |
| #endif |
| |
| /* Verify input strings and measure their lengths */ |
| for(nA=0; zA[nA]; nA++){ |
| if( zA[nA]>127 ) return -2; |
| } |
| for(nB=0; zB[nB]; nB++){ |
| if( zB[nB]>127 ) return -2; |
| } |
| |
| /* Special processing if either string is empty */ |
| if( nA==0 ){ |
| cBprev = dc; |
| for(xB=res=0; (cB = zB[xB])!=0; xB++){ |
| res += insertOrDeleteCost(cBprev, cB)/FINAL_INS_COST_DIV; |
| cBprev = cB; |
| } |
| return res; |
| } |
| if( nB==0 ){ |
| cAprev = dc; |
| for(xA=res=0; (cA = zA[xA])!=0; xA++){ |
| res += insertOrDeleteCost(cAprev, cA); |
| cAprev = cA; |
| } |
| return res; |
| } |
| |
| /* A is a prefix of B */ |
| if( zA[0]=='*' && zA[1]==0 ) return 0; |
| |
| /* Allocate and initialize the Wagner matrix */ |
| if( nB<(sizeof(mStack)*4)/(sizeof(mStack[0])*5) ){ |
| m = mStack; |
| }else{ |
| m = toFree = sqlite3_malloc( (nB+1)*5*sizeof(m[0])/4 ); |
| if( m==0 ) return -3; |
| } |
| cx = (char*)&m[nB+1]; |
| |
| /* Compute the Wagner edit distance */ |
| m[0] = 0; |
| cx[0] = dc; |
| cBprev = dc; |
| for(xB=1; xB<=nB; xB++){ |
| cB = zB[xB-1]; |
| cx[xB] = cB; |
| m[xB] = m[xB-1] + insertOrDeleteCost(cBprev, cB); |
| cBprev = cB; |
| } |
| cAprev = dc; |
| for(xA=1; xA<=nA; xA++){ |
| int lastA = (xA==nA); |
| cA = zA[xA-1]; |
| if( cA=='*' && lastA ) break; |
| d = m[0]; |
| dc = cx[0]; |
| m[0] = d + insertOrDeleteCost(cAprev, cA); |
| cBprev = 0; |
| for(xB=1; xB<=nB; xB++){ |
| int totalCost, insCost, delCost, subCost, ncx; |
| cB = zB[xB-1]; |
| |
| /* Cost to insert cB */ |
| insCost = insertOrDeleteCost(cx[xB-1], cB); |
| if( lastA ) insCost /= FINAL_INS_COST_DIV; |
| |
| /* Cost to delete cA */ |
| delCost = insertOrDeleteCost(cx[xB], cA); |
| |
| /* Cost to substitute cA->cB */ |
| subCost = substituteCost(cx[xB-1], cA, cB); |
| |
| /* Best cost */ |
| totalCost = insCost + m[xB-1]; |
| ncx = cB; |
| if( (delCost + m[xB])<totalCost ){ |
| totalCost = delCost + m[xB]; |
| ncx = cA; |
| } |
| if( (subCost + d)<totalCost ){ |
| totalCost = subCost + d; |
| } |
| |
| #if 0 |
| printf("%d,%d d=%4d u=%4d r=%4d dc=%c cA=%c cB=%c" |
| " ins=%4d del=%4d sub=%4d t=%4d ncx=%c\n", |
| xA, xB, d, m[xB], m[xB-1], dc?dc:' ', cA, cB, |
| insCost, delCost, subCost, totalCost, ncx?ncx:' '); |
| #endif |
| |
| /* Update the matrix */ |
| d = m[xB]; |
| dc = cx[xB]; |
| m[xB] = totalCost; |
| cx[xB] = ncx; |
| cBprev = cB; |
| } |
| cAprev = cA; |
| } |
| |
| /* Free the wagner matrix and return the result */ |
| if( cA=='*' && nB>nA ){ |
| res = m[nA]; |
| for(xB=nA+1; xB<=nB; xB++){ |
| if( m[xB]<res ) res = m[xB]; |
| } |
| }else{ |
| res = m[nB]; |
| } |
| sqlite3_free(toFree); |
| return res; |
| } |
| |
| /* |
| ** Function: editdist(A,B) |
| ** |
| ** Return the cost of transforming string A into string B. Both strings |
| ** must be pure ASCII text. If A ends with '*' then it is assumed to be |
| ** a prefix of B and extra characters on the end of B have minimal additional |
| ** cost. |
| */ |
| static void editdistSqlFunc( |
| sqlite3_context *context, |
| int argc, |
| sqlite3_value **argv |
| ){ |
| int res = editdist((const char*)sqlite3_value_text(argv[0]), |
| (const char*)sqlite3_value_text(argv[1])); |
| if( res<0 ){ |
| if( res==(-3) ){ |
| sqlite3_result_error_nomem(context); |
| }else if( res==(-2) ){ |
| sqlite3_result_error(context, "non-ASCII input to editdist()", -1); |
| }else{ |
| sqlite3_result_error(context, "NULL input to editdist()", -1); |
| } |
| }else{ |
| sqlite3_result_int(context, res); |
| } |
| } |
| |
| #if !SQLITE_CORE |
| /* |
| ** This lookup table is used to help decode the first byte of |
| ** a multi-byte UTF8 character. |
| */ |
| static const unsigned char sqlite3Utf8Trans1[] = { |
| 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, |
| 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, |
| 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, |
| 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, |
| 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, |
| 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, |
| 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, |
| 0x00, 0x01, 0x02, 0x03, 0x00, 0x01, 0x00, 0x00, |
| }; |
| #endif |
| |
| /* |
| ** Return the value of the first UTF-8 character in the string. |
| */ |
| static int utf8Read(const unsigned char *z, int n, int *pSize){ |
| int c, i; |
| |
| if( n==0 ){ |
| c = i = 0; |
| }else{ |
| c = z[0]; |
| i = 1; |
| if( c>=0xc0 ){ |
| c = sqlite3Utf8Trans1[c-0xc0]; |
| while( i<n && (z[i] & 0xc0)==0x80 ){ |
| c = (c<<6) + (0x3f & z[i++]); |
| } |
| } |
| } |
| *pSize = i; |
| return c; |
| } |
| |
| /* |
| ** Table of translations from unicode characters into ASCII. |
| */ |
| static const struct { |
| unsigned short int cFrom; |
| unsigned char cTo0, cTo1; |
| } translit[] = { |
| { 0x00A0, 0x20, 0x00 }, /* to */ |
| { 0x00B5, 0x75, 0x00 }, /* µ to u */ |
| { 0x00C0, 0x41, 0x00 }, /* À to A */ |
| { 0x00C1, 0x41, 0x00 }, /* Á to A */ |
| { 0x00C2, 0x41, 0x00 }, /* Â to A */ |
| { 0x00C3, 0x41, 0x00 }, /* Ã to A */ |
| { 0x00C4, 0x41, 0x65 }, /* Ä to Ae */ |
| { 0x00C5, 0x41, 0x61 }, /* Å to Aa */ |
| { 0x00C6, 0x41, 0x45 }, /* Æ to AE */ |
| { 0x00C7, 0x43, 0x00 }, /* Ç to C */ |
| { 0x00C8, 0x45, 0x00 }, /* È to E */ |
| { 0x00C9, 0x45, 0x00 }, /* É to E */ |
| { 0x00CA, 0x45, 0x00 }, /* Ê to E */ |
| { 0x00CB, 0x45, 0x00 }, /* Ë to E */ |
| { 0x00CC, 0x49, 0x00 }, /* Ì to I */ |
| { 0x00CD, 0x49, 0x00 }, /* Í to I */ |
| { 0x00CE, 0x49, 0x00 }, /* Î to I */ |
| { 0x00CF, 0x49, 0x00 }, /* Ï to I */ |
| { 0x00D0, 0x44, 0x00 }, /* Ð to D */ |
| { 0x00D1, 0x4E, 0x00 }, /* Ñ to N */ |
| { 0x00D2, 0x4F, 0x00 }, /* Ò to O */ |
| { 0x00D3, 0x4F, 0x00 }, /* Ó to O */ |
| { 0x00D4, 0x4F, 0x00 }, /* Ô to O */ |
| { 0x00D5, 0x4F, 0x00 }, /* Õ to O */ |
| { 0x00D6, 0x4F, 0x65 }, /* Ö to Oe */ |
| { 0x00D7, 0x78, 0x00 }, /* × to x */ |
| { 0x00D8, 0x4F, 0x00 }, /* Ø to O */ |
| { 0x00D9, 0x55, 0x00 }, /* Ù to U */ |
| { 0x00DA, 0x55, 0x00 }, /* Ú to U */ |
| { 0x00DB, 0x55, 0x00 }, /* Û to U */ |
| { 0x00DC, 0x55, 0x65 }, /* Ü to Ue */ |
| { 0x00DD, 0x59, 0x00 }, /* Ý to Y */ |
| { 0x00DE, 0x54, 0x68 }, /* Þ to Th */ |
| { 0x00DF, 0x73, 0x73 }, /* ß to ss */ |
| { 0x00E0, 0x61, 0x00 }, /* à to a */ |
| { 0x00E1, 0x61, 0x00 }, /* á to a */ |
| { 0x00E2, 0x61, 0x00 }, /* â to a */ |
| { 0x00E3, 0x61, 0x00 }, /* ã to a */ |
| { 0x00E4, 0x61, 0x65 }, /* ä to ae */ |
| { 0x00E5, 0x61, 0x61 }, /* å to aa */ |
| { 0x00E6, 0x61, 0x65 }, /* æ to ae */ |
| { 0x00E7, 0x63, 0x00 }, /* ç to c */ |
| { 0x00E8, 0x65, 0x00 }, /* è to e */ |
| { 0x00E9, 0x65, 0x00 }, /* é to e */ |
| { 0x00EA, 0x65, 0x00 }, /* ê to e */ |
| { 0x00EB, 0x65, 0x00 }, /* ë to e */ |
| { 0x00EC, 0x69, 0x00 }, /* ì to i */ |
| { 0x00ED, 0x69, 0x00 }, /* í to i */ |
| { 0x00EE, 0x69, 0x00 }, /* î to i */ |
| { 0x00EF, 0x69, 0x00 }, /* ï to i */ |
| { 0x00F0, 0x64, 0x00 }, /* ð to d */ |
| { 0x00F1, 0x6E, 0x00 }, /* ñ to n */ |
| { 0x00F2, 0x6F, 0x00 }, /* ò to o */ |
| { 0x00F3, 0x6F, 0x00 }, /* ó to o */ |
| { 0x00F4, 0x6F, 0x00 }, /* ô to o */ |
| { 0x00F5, 0x6F, 0x00 }, /* õ to o */ |
| { 0x00F6, 0x6F, 0x65 }, /* ö to oe */ |
| { 0x00F7, 0x3A, 0x00 }, /* ÷ to : */ |
| { 0x00F8, 0x6F, 0x00 }, /* ø to o */ |
| { 0x00F9, 0x75, 0x00 }, /* ù to u */ |
| { 0x00FA, 0x75, 0x00 }, /* ú to u */ |
| { 0x00FB, 0x75, 0x00 }, /* û to u */ |
| { 0x00FC, 0x75, 0x65 }, /* ü to ue */ |
| { 0x00FD, 0x79, 0x00 }, /* ý to y */ |
| { 0x00FE, 0x74, 0x68 }, /* þ to th */ |
| { 0x00FF, 0x79, 0x00 }, /* ÿ to y */ |
| { 0x0100, 0x41, 0x00 }, /* Ā to A */ |
| { 0x0101, 0x61, 0x00 }, /* ā to a */ |
| { 0x0102, 0x41, 0x00 }, /* Ă to A */ |
| { 0x0103, 0x61, 0x00 }, /* ă to a */ |
| { 0x0104, 0x41, 0x00 }, /* Ą to A */ |
| { 0x0105, 0x61, 0x00 }, /* ą to a */ |
| { 0x0106, 0x43, 0x00 }, /* Ć to C */ |
| { 0x0107, 0x63, 0x00 }, /* ć to c */ |
| { 0x0108, 0x43, 0x68 }, /* Ĉ to Ch */ |
| { 0x0109, 0x63, 0x68 }, /* ĉ to ch */ |
| { 0x010A, 0x43, 0x00 }, /* Ċ to C */ |
| { 0x010B, 0x63, 0x00 }, /* ċ to c */ |
| { 0x010C, 0x43, 0x00 }, /* Č to C */ |
| { 0x010D, 0x63, 0x00 }, /* č to c */ |
| { 0x010E, 0x44, 0x00 }, /* Ď to D */ |
| { 0x010F, 0x64, 0x00 }, /* ď to d */ |
| { 0x0110, 0x44, 0x00 }, /* Đ to D */ |
| { 0x0111, 0x64, 0x00 }, /* đ to d */ |
| { 0x0112, 0x45, 0x00 }, /* Ē to E */ |
| { 0x0113, 0x65, 0x00 }, /* ē to e */ |
| { 0x0114, 0x45, 0x00 }, /* Ĕ to E */ |
| { 0x0115, 0x65, 0x00 }, /* ĕ to e */ |
| { 0x0116, 0x45, 0x00 }, /* Ė to E */ |
| { 0x0117, 0x65, 0x00 }, /* ė to e */ |
| { 0x0118, 0x45, 0x00 }, /* Ę to E */ |
| { 0x0119, 0x65, 0x00 }, /* ę to e */ |
| { 0x011A, 0x45, 0x00 }, /* Ě to E */ |
| { 0x011B, 0x65, 0x00 }, /* ě to e */ |
| { 0x011C, 0x47, 0x68 }, /* Ĝ to Gh */ |
| { 0x011D, 0x67, 0x68 }, /* ĝ to gh */ |
| { 0x011E, 0x47, 0x00 }, /* Ğ to G */ |
| { 0x011F, 0x67, 0x00 }, /* ğ to g */ |
| { 0x0120, 0x47, 0x00 }, /* Ġ to G */ |
| { 0x0121, 0x67, 0x00 }, /* ġ to g */ |
| { 0x0122, 0x47, 0x00 }, /* Ģ to G */ |
| { 0x0123, 0x67, 0x00 }, /* ģ to g */ |
| { 0x0124, 0x48, 0x68 }, /* Ĥ to Hh */ |
| { 0x0125, 0x68, 0x68 }, /* ĥ to hh */ |
| { 0x0126, 0x48, 0x00 }, /* Ħ to H */ |
| { 0x0127, 0x68, 0x00 }, /* ħ to h */ |
| { 0x0128, 0x49, 0x00 }, /* Ĩ to I */ |
| { 0x0129, 0x69, 0x00 }, /* ĩ to i */ |
| { 0x012A, 0x49, 0x00 }, /* Ī to I */ |
| { 0x012B, 0x69, 0x00 }, /* ī to i */ |
| { 0x012C, 0x49, 0x00 }, /* Ĭ to I */ |
| { 0x012D, 0x69, 0x00 }, /* ĭ to i */ |
| { 0x012E, 0x49, 0x00 }, /* Į to I */ |
| { 0x012F, 0x69, 0x00 }, /* į to i */ |
| { 0x0130, 0x49, 0x00 }, /* İ to I */ |
| { 0x0131, 0x69, 0x00 }, /* ı to i */ |
| { 0x0132, 0x49, 0x4A }, /* IJ to IJ */ |
| { 0x0133, 0x69, 0x6A }, /* ij to ij */ |
| { 0x0134, 0x4A, 0x68 }, /* Ĵ to Jh */ |
| { 0x0135, 0x6A, 0x68 }, /* ĵ to jh */ |
| { 0x0136, 0x4B, 0x00 }, /* Ķ to K */ |
| { 0x0137, 0x6B, 0x00 }, /* ķ to k */ |
| { 0x0138, 0x6B, 0x00 }, /* ĸ to k */ |
| { 0x0139, 0x4C, 0x00 }, /* Ĺ to L */ |
| { 0x013A, 0x6C, 0x00 }, /* ĺ to l */ |
| { 0x013B, 0x4C, 0x00 }, /* Ļ to L */ |
| { 0x013C, 0x6C, 0x00 }, /* ļ to l */ |
| { 0x013D, 0x4C, 0x00 }, /* Ľ to L */ |
| { 0x013E, 0x6C, 0x00 }, /* ľ to l */ |
| { 0x013F, 0x4C, 0x2E }, /* Ŀ to L. */ |
| { 0x0140, 0x6C, 0x2E }, /* ŀ to l. */ |
| { 0x0141, 0x4C, 0x00 }, /* Ł to L */ |
| { 0x0142, 0x6C, 0x00 }, /* ł to l */ |
| { 0x0143, 0x4E, 0x00 }, /* Ń to N */ |
| { 0x0144, 0x6E, 0x00 }, /* ń to n */ |
| { 0x0145, 0x4E, 0x00 }, /* Ņ to N */ |
| { 0x0146, 0x6E, 0x00 }, /* ņ to n */ |
| { 0x0147, 0x4E, 0x00 }, /* Ň to N */ |
| { 0x0148, 0x6E, 0x00 }, /* ň to n */ |
| { 0x0149, 0x27, 0x6E }, /* ʼn to 'n */ |
| { 0x014A, 0x4E, 0x47 }, /* Ŋ to NG */ |
| { 0x014B, 0x6E, 0x67 }, /* ŋ to ng */ |
| { 0x014C, 0x4F, 0x00 }, /* Ō to O */ |
| { 0x014D, 0x6F, 0x00 }, /* ō to o */ |
| { 0x014E, 0x4F, 0x00 }, /* Ŏ to O */ |
| { 0x014F, 0x6F, 0x00 }, /* ŏ to o */ |
| { 0x0150, 0x4F, 0x00 }, /* Ő to O */ |
| { 0x0151, 0x6F, 0x00 }, /* ő to o */ |
| { 0x0152, 0x4F, 0x45 }, /* Œ to OE */ |
| { 0x0153, 0x6F, 0x65 }, /* œ to oe */ |
| { 0x0154, 0x52, 0x00 }, /* Ŕ to R */ |
| { 0x0155, 0x72, 0x00 }, /* ŕ to r */ |
| { 0x0156, 0x52, 0x00 }, /* Ŗ to R */ |
| { 0x0157, 0x72, 0x00 }, /* ŗ to r */ |
| { 0x0158, 0x52, 0x00 }, /* Ř to R */ |
| { 0x0159, 0x72, 0x00 }, /* ř to r */ |
| { 0x015A, 0x53, 0x00 }, /* Ś to S */ |
| { 0x015B, 0x73, 0x00 }, /* ś to s */ |
| { 0x015C, 0x53, 0x68 }, /* Ŝ to Sh */ |
| { 0x015D, 0x73, 0x68 }, /* ŝ to sh */ |
| { 0x015E, 0x53, 0x00 }, /* Ş to S */ |
| { 0x015F, 0x73, 0x00 }, /* ş to s */ |
| { 0x0160, 0x53, 0x00 }, /* Š to S */ |
| { 0x0161, 0x73, 0x00 }, /* š to s */ |
| { 0x0162, 0x54, 0x00 }, /* Ţ to T */ |
| { 0x0163, 0x74, 0x00 }, /* ţ to t */ |
| { 0x0164, 0x54, 0x00 }, /* Ť to T */ |
| { 0x0165, 0x74, 0x00 }, /* ť to t */ |
| { 0x0166, 0x54, 0x00 }, /* Ŧ to T */ |
| { 0x0167, 0x74, 0x00 }, /* ŧ to t */ |
| { 0x0168, 0x55, 0x00 }, /* Ũ to U */ |
| { 0x0169, 0x75, 0x00 }, /* ũ to u */ |
| { 0x016A, 0x55, 0x00 }, /* Ū to U */ |
| { 0x016B, 0x75, 0x00 }, /* ū to u */ |
| { 0x016C, 0x55, 0x00 }, /* Ŭ to U */ |
| { 0x016D, 0x75, 0x00 }, /* ŭ to u */ |
| { 0x016E, 0x55, 0x00 }, /* Ů to U */ |
| { 0x016F, 0x75, 0x00 }, /* ů to u */ |
| { 0x0170, 0x55, 0x00 }, /* Ű to U */ |
| { 0x0171, 0x75, 0x00 }, /* ű to u */ |
| { 0x0172, 0x55, 0x00 }, /* Ų to U */ |
| { 0x0173, 0x75, 0x00 }, /* ų to u */ |
| { 0x0174, 0x57, 0x00 }, /* Ŵ to W */ |
| { 0x0175, 0x77, 0x00 }, /* ŵ to w */ |
| { 0x0176, 0x59, 0x00 }, /* Ŷ to Y */ |
| { 0x0177, 0x79, 0x00 }, /* ŷ to y */ |
| { 0x0178, 0x59, 0x00 }, /* Ÿ to Y */ |
| { 0x0179, 0x5A, 0x00 }, /* Ź to Z */ |
| { 0x017A, 0x7A, 0x00 }, /* ź to z */ |
| { 0x017B, 0x5A, 0x00 }, /* Ż to Z */ |
| { 0x017C, 0x7A, 0x00 }, /* ż to z */ |
| { 0x017D, 0x5A, 0x00 }, /* Ž to Z */ |
| { 0x017E, 0x7A, 0x00 }, /* ž to z */ |
| { 0x017F, 0x73, 0x00 }, /* ſ to s */ |
| { 0x0192, 0x66, 0x00 }, /* ƒ to f */ |
| { 0x0218, 0x53, 0x00 }, /* Ș to S */ |
| { 0x0219, 0x73, 0x00 }, /* ș to s */ |
| { 0x021A, 0x54, 0x00 }, /* Ț to T */ |
| { 0x021B, 0x74, 0x00 }, /* ț to t */ |
| { 0x0386, 0x41, 0x00 }, /* Ά to A */ |
| { 0x0388, 0x45, 0x00 }, /* Έ to E */ |
| { 0x0389, 0x49, 0x00 }, /* Ή to I */ |
| { 0x038A, 0x49, 0x00 }, /* Ί to I */ |
| { 0x038C, 0x4f, 0x00 }, /* Ό to O */ |
| { 0x038E, 0x59, 0x00 }, /* Ύ to Y */ |
| { 0x038F, 0x4f, 0x00 }, /* Ώ to O */ |
| { 0x0390, 0x69, 0x00 }, /* ΐ to i */ |
| { 0x0391, 0x41, 0x00 }, /* Α to A */ |
| { 0x0392, 0x42, 0x00 }, /* Β to B */ |
| { 0x0393, 0x47, 0x00 }, /* Γ to G */ |
| { 0x0394, 0x44, 0x00 }, /* Δ to D */ |
| { 0x0395, 0x45, 0x00 }, /* Ε to E */ |
| { 0x0396, 0x5a, 0x00 }, /* Ζ to Z */ |
| { 0x0397, 0x49, 0x00 }, /* Η to I */ |
| { 0x0398, 0x54, 0x68 }, /* Θ to Th */ |
| { 0x0399, 0x49, 0x00 }, /* Ι to I */ |
| { 0x039A, 0x4b, 0x00 }, /* Κ to K */ |
| { 0x039B, 0x4c, 0x00 }, /* Λ to L */ |
| { 0x039C, 0x4d, 0x00 }, /* Μ to M */ |
| { 0x039D, 0x4e, 0x00 }, /* Ν to N */ |
| { 0x039E, 0x58, 0x00 }, /* Ξ to X */ |
| { 0x039F, 0x4f, 0x00 }, /* Ο to O */ |
| { 0x03A0, 0x50, 0x00 }, /* Π to P */ |
| { 0x03A1, 0x52, 0x00 }, /* Ρ to R */ |
| { 0x03A3, 0x53, 0x00 }, /* Σ to S */ |
| { 0x03A4, 0x54, 0x00 }, /* Τ to T */ |
| { 0x03A5, 0x59, 0x00 }, /* Υ to Y */ |
| { 0x03A6, 0x46, 0x00 }, /* Φ to F */ |
| { 0x03A7, 0x43, 0x68 }, /* Χ to Ch */ |
| { 0x03A8, 0x50, 0x73 }, /* Ψ to Ps */ |
| { 0x03A9, 0x4f, 0x00 }, /* Ω to O */ |
| { 0x03AA, 0x49, 0x00 }, /* Ϊ to I */ |
| { 0x03AB, 0x59, 0x00 }, /* Ϋ to Y */ |
| { 0x03AC, 0x61, 0x00 }, /* ά to a */ |
| { 0x03AD, 0x65, 0x00 }, /* έ to e */ |
| { 0x03AE, 0x69, 0x00 }, /* ή to i */ |
| { 0x03AF, 0x69, 0x00 }, /* ί to i */ |
| { 0x03B1, 0x61, 0x00 }, /* α to a */ |
| { 0x03B2, 0x62, 0x00 }, /* β to b */ |
| { 0x03B3, 0x67, 0x00 }, /* γ to g */ |
| { 0x03B4, 0x64, 0x00 }, /* δ to d */ |
| { 0x03B5, 0x65, 0x00 }, /* ε to e */ |
| { 0x03B6, 0x7a, 0x00 }, /* ζ to z */ |
| { 0x03B7, 0x69, 0x00 }, /* η to i */ |
| { 0x03B8, 0x74, 0x68 }, /* θ to th */ |
| { 0x03B9, 0x69, 0x00 }, /* ι to i */ |
| { 0x03BA, 0x6b, 0x00 }, /* κ to k */ |
| { 0x03BB, 0x6c, 0x00 }, /* λ to l */ |
| { 0x03BC, 0x6d, 0x00 }, /* μ to m */ |
| { 0x03BD, 0x6e, 0x00 }, /* ν to n */ |
| { 0x03BE, 0x78, 0x00 }, /* ξ to x */ |
| { 0x03BF, 0x6f, 0x00 }, /* ο to o */ |
| { 0x03C0, 0x70, 0x00 }, /* π to p */ |
| { 0x03C1, 0x72, 0x00 }, /* ρ to r */ |
| { 0x03C3, 0x73, 0x00 }, /* σ to s */ |
| { 0x03C4, 0x74, 0x00 }, /* τ to t */ |
| { 0x03C5, 0x79, 0x00 }, /* υ to y */ |
| { 0x03C6, 0x66, 0x00 }, /* φ to f */ |
| { 0x03C7, 0x63, 0x68 }, /* χ to ch */ |
| { 0x03C8, 0x70, 0x73 }, /* ψ to ps */ |
| { 0x03C9, 0x6f, 0x00 }, /* ω to o */ |
| { 0x03CA, 0x69, 0x00 }, /* ϊ to i */ |
| { 0x03CB, 0x79, 0x00 }, /* ϋ to y */ |
| { 0x03CC, 0x6f, 0x00 }, /* ό to o */ |
| { 0x03CD, 0x79, 0x00 }, /* ύ to y */ |
| { 0x03CE, 0x69, 0x00 }, /* ώ to i */ |
| { 0x0400, 0x45, 0x00 }, /* Ѐ to E */ |
| { 0x0401, 0x45, 0x00 }, /* Ё to E */ |
| { 0x0402, 0x44, 0x00 }, /* Ђ to D */ |
| { 0x0403, 0x47, 0x00 }, /* Ѓ to G */ |
| { 0x0404, 0x45, 0x00 }, /* Є to E */ |
| { 0x0405, 0x5a, 0x00 }, /* Ѕ to Z */ |
| { 0x0406, 0x49, 0x00 }, /* І to I */ |
| { 0x0407, 0x49, 0x00 }, /* Ї to I */ |
| { 0x0408, 0x4a, 0x00 }, /* Ј to J */ |
| { 0x0409, 0x49, 0x00 }, /* Љ to I */ |
| { 0x040A, 0x4e, 0x00 }, /* Њ to N */ |
| { 0x040B, 0x44, 0x00 }, /* Ћ to D */ |
| { 0x040C, 0x4b, 0x00 }, /* Ќ to K */ |
| { 0x040D, 0x49, 0x00 }, /* Ѝ to I */ |
| { 0x040E, 0x55, 0x00 }, /* Ў to U */ |
| { 0x040F, 0x44, 0x00 }, /* Џ to D */ |
| { 0x0410, 0x41, 0x00 }, /* А to A */ |
| { 0x0411, 0x42, 0x00 }, /* Б to B */ |
| { 0x0412, 0x56, 0x00 }, /* В to V */ |
| { 0x0413, 0x47, 0x00 }, /* Г to G */ |
| { 0x0414, 0x44, 0x00 }, /* Д to D */ |
| { 0x0415, 0x45, 0x00 }, /* Е to E */ |
| { 0x0416, 0x5a, 0x68 }, /* Ж to Zh */ |
| { 0x0417, 0x5a, 0x00 }, /* З to Z */ |
| { 0x0418, 0x49, 0x00 }, /* И to I */ |
| { 0x0419, 0x49, 0x00 }, /* Й to I */ |
| { 0x041A, 0x4b, 0x00 }, /* К to K */ |
| { 0x041B, 0x4c, 0x00 }, /* Л to L */ |
| { 0x041C, 0x4d, 0x00 }, /* М to M */ |
| { 0x041D, 0x4e, 0x00 }, /* Н to N */ |
| { 0x041E, 0x4f, 0x00 }, /* О to O */ |
| { 0x041F, 0x50, 0x00 }, /* П to P */ |
| { 0x0420, 0x52, 0x00 }, /* Р to R */ |
| { 0x0421, 0x53, 0x00 }, /* С to S */ |
| { 0x0422, 0x54, 0x00 }, /* Т to T */ |
| { 0x0423, 0x55, 0x00 }, /* У to U */ |
| { 0x0424, 0x46, 0x00 }, /* Ф to F */ |
| { 0x0425, 0x4b, 0x68 }, /* Х to Kh */ |
| { 0x0426, 0x54, 0x63 }, /* Ц to Tc */ |
| { 0x0427, 0x43, 0x68 }, /* Ч to Ch */ |
| { 0x0428, 0x53, 0x68 }, /* Ш to Sh */ |
| { 0x0429, 0x53, 0x68 }, /* Щ to Shch */ |
| { 0x042B, 0x59, 0x00 }, /* Ы to Y */ |
| { 0x042D, 0x45, 0x00 }, /* Э to E */ |
| { 0x042E, 0x49, 0x75 }, /* Ю to Iu */ |
| { 0x042F, 0x49, 0x61 }, /* Я to Ia */ |
| { 0x0430, 0x61, 0x00 }, /* а to a */ |
| { 0x0431, 0x62, 0x00 }, /* б to b */ |
| { 0x0432, 0x76, 0x00 }, /* в to v */ |
| { 0x0433, 0x67, 0x00 }, /* г to g */ |
| { 0x0434, 0x64, 0x00 }, /* д to d */ |
| { 0x0435, 0x65, 0x00 }, /* е to e */ |
| { 0x0436, 0x7a, 0x68 }, /* ж to zh */ |
| { 0x0437, 0x7a, 0x00 }, /* з to z */ |
| { 0x0438, 0x69, 0x00 }, /* и to i */ |
| { 0x0439, 0x69, 0x00 }, /* й to i */ |
| { 0x043A, 0x6b, 0x00 }, /* к to k */ |
| { 0x043B, 0x6c, 0x00 }, /* л to l */ |
| { 0x043C, 0x6d, 0x00 }, /* м to m */ |
| { 0x043D, 0x6e, 0x00 }, /* н to n */ |
| { 0x043E, 0x6f, 0x00 }, /* о to o */ |
| { 0x043F, 0x70, 0x00 }, /* п to p */ |
| { 0x0440, 0x72, 0x00 }, /* р to r */ |
| { 0x0441, 0x73, 0x00 }, /* с to s */ |
| { 0x0442, 0x74, 0x00 }, /* т to t */ |
| { 0x0443, 0x75, 0x00 }, /* у to u */ |
| { 0x0444, 0x66, 0x00 }, /* ф to f */ |
| { 0x0445, 0x6b, 0x68 }, /* х to kh */ |
| { 0x0446, 0x74, 0x63 }, /* ц to tc */ |
| { 0x0447, 0x63, 0x68 }, /* ч to ch */ |
| { 0x0448, 0x73, 0x68 }, /* ш to sh */ |
| { 0x0449, 0x73, 0x68 }, /* щ to shch */ |
| { 0x044B, 0x79, 0x00 }, /* ы to y */ |
| { 0x044D, 0x65, 0x00 }, /* э to e */ |
| { 0x044E, 0x69, 0x75 }, /* ю to iu */ |
| { 0x044F, 0x69, 0x61 }, /* я to ia */ |
| { 0x0450, 0x65, 0x00 }, /* ѐ to e */ |
| { 0x0451, 0x65, 0x00 }, /* ё to e */ |
| { 0x0452, 0x64, 0x00 }, /* ђ to d */ |
| { 0x0453, 0x67, 0x00 }, /* ѓ to g */ |
| { 0x0454, 0x65, 0x00 }, /* є to e */ |
| { 0x0455, 0x7a, 0x00 }, /* ѕ to z */ |
| { 0x0456, 0x69, 0x00 }, /* і to i */ |
| { 0x0457, 0x69, 0x00 }, /* ї to i */ |
| { 0x0458, 0x6a, 0x00 }, /* ј to j */ |
| { 0x0459, 0x69, 0x00 }, /* љ to i */ |
| { 0x045A, 0x6e, 0x00 }, /* њ to n */ |
| { 0x045B, 0x64, 0x00 }, /* ћ to d */ |
| { 0x045C, 0x6b, 0x00 }, /* ќ to k */ |
| { 0x045D, 0x69, 0x00 }, /* ѝ to i */ |
| { 0x045E, 0x75, 0x00 }, /* ў to u */ |
| { 0x045F, 0x64, 0x00 }, /* џ to d */ |
| { 0x1E02, 0x42, 0x00 }, /* Ḃ to B */ |
| { 0x1E03, 0x62, 0x00 }, /* ḃ to b */ |
| { 0x1E0A, 0x44, 0x00 }, /* Ḋ to D */ |
| { 0x1E0B, 0x64, 0x00 }, /* ḋ to d */ |
| { 0x1E1E, 0x46, 0x00 }, /* Ḟ to F */ |
| { 0x1E1F, 0x66, 0x00 }, /* ḟ to f */ |
| { 0x1E40, 0x4D, 0x00 }, /* Ṁ to M */ |
| { 0x1E41, 0x6D, 0x00 }, /* ṁ to m */ |
| { 0x1E56, 0x50, 0x00 }, /* Ṗ to P */ |
| { 0x1E57, 0x70, 0x00 }, /* ṗ to p */ |
| { 0x1E60, 0x53, 0x00 }, /* Ṡ to S */ |
| { 0x1E61, 0x73, 0x00 }, /* ṡ to s */ |
| { 0x1E6A, 0x54, 0x00 }, /* Ṫ to T */ |
| { 0x1E6B, 0x74, 0x00 }, /* ṫ to t */ |
| { 0x1E80, 0x57, 0x00 }, /* Ẁ to W */ |
| { 0x1E81, 0x77, 0x00 }, /* ẁ to w */ |
| { 0x1E82, 0x57, 0x00 }, /* Ẃ to W */ |
| { 0x1E83, 0x77, 0x00 }, /* ẃ to w */ |
| { 0x1E84, 0x57, 0x00 }, /* Ẅ to W */ |
| { 0x1E85, 0x77, 0x00 }, /* ẅ to w */ |
| { 0x1EF2, 0x59, 0x00 }, /* Ỳ to Y */ |
| { 0x1EF3, 0x79, 0x00 }, /* ỳ to y */ |
| { 0xFB00, 0x66, 0x66 }, /* ff to ff */ |
| { 0xFB01, 0x66, 0x69 }, /* fi to fi */ |
| { 0xFB02, 0x66, 0x6C }, /* fl to fl */ |
| { 0xFB05, 0x73, 0x74 }, /* ſt to st */ |
| { 0xFB06, 0x73, 0x74 }, /* st to st */ |
| }; |
| |
| /* |
| ** Convert the input string from UTF-8 into pure ASCII by converting |
| ** all non-ASCII characters to some combination of characters in the |
| ** ASCII subset. |
| ** |
| ** The returned string might contain more characters than the input. |
| ** |
| ** Space to hold the returned string comes from sqlite3_malloc() and |
| ** should be freed by the caller. |
| */ |
| static unsigned char *transliterate(const unsigned char *zIn, int nIn){ |
| unsigned char *zOut = sqlite3_malloc( nIn*4 + 1 ); |
| int i, c, sz, nOut; |
| if( zOut==0 ) return 0; |
| i = nOut = 0; |
| while( i<nIn ){ |
| c = utf8Read(zIn, nIn, &sz); |
| zIn += sz; |
| nIn -= sz; |
| if( c<=127 ){ |
| zOut[nOut++] = c; |
| }else{ |
| int xTop, xBtm, x; |
| xTop = sizeof(translit)/sizeof(translit[0]) - 1; |
| xBtm = 0; |
| while( xTop>=xBtm ){ |
| x = (xTop + xBtm)/2; |
| if( translit[x].cFrom==c ){ |
| zOut[nOut++] = translit[x].cTo0; |
| if( translit[x].cTo1 ){ |
| zOut[nOut++] = translit[x].cTo1; |
| /* Add an extra "ch" after the "sh" for Щ and щ */ |
| if( c==0x0429 || c== 0x0449 ){ |
| zOut[nOut++] = 'c'; |
| zOut[nOut++] = 'h'; |
| } |
| } |
| c = 0; |
| break; |
| }else if( translit[x].cFrom>c ){ |
| xTop = x-1; |
| }else{ |
| xBtm = x+1; |
| } |
| } |
| if( c ) zOut[nOut++] = '?'; |
| } |
| } |
| zOut[nOut] = 0; |
| return zOut; |
| } |
| |
| /* |
| ** spellfix1_translit(X) |
| ** |
| ** Convert a string that contains non-ASCII Roman characters into |
| ** pure ASCII. |
| */ |
| static void transliterateSqlFunc( |
| sqlite3_context *context, |
| int argc, |
| sqlite3_value **argv |
| ){ |
| const unsigned char *zIn = sqlite3_value_text(argv[0]); |
| int nIn = sqlite3_value_bytes(argv[0]); |
| unsigned char *zOut = transliterate(zIn, nIn); |
| if( zOut==0 ){ |
| sqlite3_result_error_nomem(context); |
| }else{ |
| sqlite3_result_text(context, (char*)zOut, -1, sqlite3_free); |
| } |
| } |
| |
| /* |
| ** spellfix1_scriptcode(X) |
| ** |
| ** Try to determine the dominant script used by the word X and return |
| ** its ISO 15924 numeric code. |
| ** |
| ** The current implementation only understands the following scripts: |
| ** |
| ** 215 (Latin) |
| ** 220 (Cyrillic) |
| ** 200 (Greek) |
| ** |
| ** This routine will return 998 if the input X contains characters from |
| ** two or more of the above scripts or 999 if X contains no characters |
| ** from any of the above scripts. |
| */ |
| static void scriptCodeSqlFunc( |
| sqlite3_context *context, |
| int argc, |
| sqlite3_value **argv |
| ){ |
| const unsigned char *zIn = sqlite3_value_text(argv[0]); |
| int nIn = sqlite3_value_bytes(argv[0]); |
| int c, sz; |
| int scriptMask = 0; |
| int res; |
| # define SCRIPT_LATIN 0x0001 |
| # define SCRIPT_CYRILLIC 0x0002 |
| # define SCRIPT_GREEK 0x0004 |
| |
| while( nIn>0 ){ |
| c = utf8Read(zIn, nIn, &sz); |
| zIn += sz; |
| nIn -= sz; |
| if( c<0x02af ){ |
| scriptMask |= SCRIPT_LATIN; |
| }else if( c>=0x0400 && c<=0x04ff ){ |
| scriptMask |= SCRIPT_CYRILLIC; |
| }else if( c>=0x0386 && c<=0x03ce ){ |
| scriptMask |= SCRIPT_GREEK; |
| } |
| } |
| switch( scriptMask ){ |
| case 0: res = 999; break; |
| case SCRIPT_LATIN: res = 215; break; |
| case SCRIPT_CYRILLIC: res = 220; break; |
| case SCRIPT_GREEK: res = 200; break; |
| default: res = 998; break; |
| } |
| sqlite3_result_int(context, res); |
| } |
| |
| /***************************************************************************** |
| ** Fuzzy-search virtual table |
| *****************************************************************************/ |
| |
| typedef struct spellfix1_vtab spellfix1_vtab; |
| typedef struct spellfix1_cursor spellfix1_cursor; |
| |
| /* Fuzzy-search virtual table object */ |
| struct spellfix1_vtab { |
| sqlite3_vtab base; /* Base class - must be first */ |
| sqlite3 *db; /* Database connection */ |
| char *zDbName; /* Name of database holding this table */ |
| char *zTableName; /* Name of the virtual table */ |
| }; |
| |
| /* Fuzzy-search cursor object */ |
| struct spellfix1_cursor { |
| sqlite3_vtab_cursor base; /* Base class - must be first */ |
| spellfix1_vtab *pVTab; /* The table to which this cursor belongs */ |
| int nRow; /* Number of rows of content */ |
| int nAlloc; /* Number of allocated rows */ |
| int iRow; /* Current row of content */ |
| int iLang; /* Value of the lang= constraint */ |
| int iTop; /* Value of the top= constraint */ |
| int iScope; /* Value of the scope= constraint */ |
| int nSearch; /* Number of vocabulary items checked */ |
| struct spellfix1_row { /* For each row of content */ |
| sqlite3_int64 iRowid; /* Rowid for this row */ |
| char *zWord; /* Text for this row */ |
| int iRank; /* Rank for this row */ |
| int iDistance; /* Distance from pattern for this row */ |
| int iScore; /* Score for sorting */ |
| } *a; |
| }; |
| |
| /* |
| ** Construct one or more SQL statements from the format string given |
| ** and then evaluate those statements. The success code is written |
| ** into *pRc. |
| ** |
| ** If *pRc is initially non-zero then this routine is a no-op. |
| */ |
| static void spellfix1DbExec( |
| int *pRc, /* Success code */ |
| sqlite3 *db, /* Database in which to run SQL */ |
| const char *zFormat, /* Format string for SQL */ |
| ... /* Arguments to the format string */ |
| ){ |
| va_list ap; |
| char *zSql; |
| if( *pRc ) return; |
| va_start(ap, zFormat); |
| zSql = sqlite3_vmprintf(zFormat, ap); |
| va_end(ap); |
| if( zSql==0 ){ |
| *pRc = SQLITE_NOMEM; |
| }else{ |
| *pRc = sqlite3_exec(db, zSql, 0, 0, 0); |
| sqlite3_free(zSql); |
| } |
| } |
| |
| /* |
| ** xDisconnect/xDestroy method for the fuzzy-search module. |
| */ |
| static int spellfix1Uninit(int isDestroy, sqlite3_vtab *pVTab){ |
| spellfix1_vtab *p = (spellfix1_vtab*)pVTab; |
| int rc = SQLITE_OK; |
| if( isDestroy ){ |
| sqlite3 *db = p->db; |
| spellfix1DbExec(&rc, db, "DROP TABLE IF EXISTS \"%w\".\"%w_vocab\"", |
| p->zDbName, p->zTableName); |
| } |
| if( rc==SQLITE_OK ){ |
| sqlite3_free(p->zTableName); |
| sqlite3_free(p); |
| } |
| return rc; |
| } |
| static int spellfix1Disconnect(sqlite3_vtab *pVTab){ |
| return spellfix1Uninit(0, pVTab); |
| } |
| static int spellfix1Destroy(sqlite3_vtab *pVTab){ |
| return spellfix1Uninit(1, pVTab); |
| } |
| |
| /* |
| ** xConnect/xCreate method for the spellfix1 module. Arguments are: |
| ** |
| ** argv[0] -> module name ("spellfix1") |
| ** argv[1] -> database name |
| ** argv[2] -> table name |
| ** argv[3].. -> optional arguments (currently ignored) |
| */ |
| static int spellfix1Init( |
| int isCreate, |
| sqlite3 *db, |
| void *pAux, |
| int argc, const char *const*argv, |
| sqlite3_vtab **ppVTab, |
| char **pzErr |
| ){ |
| spellfix1_vtab *pNew = 0; |
| const char *zModule = argv[0]; |
| const char *zDbName = argv[1]; |
| const char *zTableName = argv[2]; |
| int nDbName; |
| int rc = SQLITE_OK; |
| |
| if( argc<3 ){ |
| *pzErr = sqlite3_mprintf( |
| "%s: wrong number of CREATE VIRTUAL TABLE arguments", argv[0] |
| ); |
| rc = SQLITE_ERROR; |
| }else{ |
| nDbName = strlen(zDbName); |
| pNew = sqlite3_malloc( sizeof(*pNew) + nDbName + 1); |
| if( pNew==0 ){ |
| rc = SQLITE_NOMEM; |
| }else{ |
| memset(pNew, 0, sizeof(*pNew)); |
| pNew->zDbName = (char*)&pNew[1]; |
| memcpy(pNew->zDbName, zDbName, nDbName+1); |
| pNew->zTableName = sqlite3_mprintf("%s", zTableName); |
| pNew->db = db; |
| if( pNew->zTableName==0 ){ |
| rc = SQLITE_NOMEM; |
| }else{ |
| rc = sqlite3_declare_vtab(db, |
| "CREATE TABLE x(word,rank,distance,langid," |
| "score,top HIDDEN,scope HIDDEN,srchcnt HIDDEN," |
| "soundslike HIDDEN)" |
| ); |
| } |
| if( rc==SQLITE_OK && isCreate ){ |
| sqlite3_uint64 r; |
| spellfix1DbExec(&rc, db, |
| "CREATE TABLE IF NOT EXISTS \"%w\".\"%w_vocab\"(\n" |
| " id INTEGER PRIMARY KEY,\n" |
| " rank INT,\n" |
| " langid INT,\n" |
| " word TEXT,\n" |
| " k1 TEXT,\n" |
| " k2 TEXT\n" |
| ");\n", |
| zDbName, zTableName |
| ); |
| sqlite3_randomness(sizeof(r), &r); |
| spellfix1DbExec(&rc, db, |
| "CREATE INDEX IF NOT EXISTS \"%w\".\"%w_index_%llx\" " |
| "ON \"%w_vocab\"(langid,k2);", |
| zDbName, zModule, r, zTableName |
| ); |
| } |
| } |
| } |
| |
| *ppVTab = (sqlite3_vtab *)pNew; |
| return rc; |
| } |
| |
| /* |
| ** The xConnect and xCreate methods |
| */ |
| static int spellfix1Connect( |
| sqlite3 *db, |
| void *pAux, |
| int argc, const char *const*argv, |
| sqlite3_vtab **ppVTab, |
| char **pzErr |
| ){ |
| return spellfix1Init(0, db, pAux, argc, argv, ppVTab, pzErr); |
| } |
| static int spellfix1Create( |
| sqlite3 *db, |
| void *pAux, |
| int argc, const char *const*argv, |
| sqlite3_vtab **ppVTab, |
| char **pzErr |
| ){ |
| return spellfix1Init(1, db, pAux, argc, argv, ppVTab, pzErr); |
| } |
| |
| /* |
| ** Reset a cursor so that it contains zero rows of content but holds |
| ** space for N rows. |
| */ |
| static void spellfix1ResetCursor(spellfix1_cursor *pCur, int N){ |
| int i; |
| for(i=0; i<pCur->nRow; i++){ |
| sqlite3_free(pCur->a[i].zWord); |
| } |
| pCur->a = sqlite3_realloc(pCur->a, sizeof(pCur->a[0])*N); |
| pCur->nAlloc = N; |
| pCur->nRow = 0; |
| pCur->iRow = 0; |
| pCur->nSearch = 0; |
| } |
| |
| /* |
| ** Close a fuzzy-search cursor. |
| */ |
| static int spellfix1Close(sqlite3_vtab_cursor *cur){ |
| spellfix1_cursor *pCur = (spellfix1_cursor *)cur; |
| spellfix1ResetCursor(pCur, 0); |
| sqlite3_free(pCur); |
| return SQLITE_OK; |
| } |
| |
| /* |
| ** Search for terms of these forms: |
| ** |
| ** (A) word MATCH $str |
| ** (B) langid == $langid |
| ** (C) top = $top |
| ** (D) scope = $scope |
| ** |
| ** The plan number is a bit mask formed with these bits: |
| ** |
| ** 0x01 (A) is found |
| ** 0x02 (B) is found |
| ** 0x04 (C) is found |
| ** 0x08 (D) is found |
| ** |
| ** filter.argv[*] values contains $str, $langid, $top, and $scope, |
| ** if specified and in that order. |
| */ |
| static int spellfix1BestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){ |
| int iPlan = 0; |
| int iLangTerm = -1; |
| int iTopTerm = -1; |
| int iScopeTerm = -1; |
| int i; |
| const struct sqlite3_index_constraint *pConstraint; |
| pConstraint = pIdxInfo->aConstraint; |
| for(i=0; i<pIdxInfo->nConstraint; i++, pConstraint++){ |
| if( pConstraint->usable==0 ) continue; |
| |
| /* Terms of the form: word MATCH $str */ |
| if( (iPlan & 1)==0 |
| && pConstraint->iColumn==0 |
| && pConstraint->op==SQLITE_INDEX_CONSTRAINT_MATCH |
| ){ |
| iPlan |= 1; |
| pIdxInfo->aConstraintUsage[i].argvIndex = 1; |
| pIdxInfo->aConstraintUsage[i].omit = 1; |
| } |
| |
| /* Terms of the form: langid = $langid */ |
| if( (iPlan & 2)==0 |
| && pConstraint->iColumn==3 |
| && pConstraint->op==SQLITE_INDEX_CONSTRAINT_EQ |
| ){ |
| iPlan |= 2; |
| iLangTerm = i; |
| } |
| |
| /* Terms of the form: top = $top */ |
| if( (iPlan & 4)==0 |
| && pConstraint->iColumn==5 |
| && pConstraint->op==SQLITE_INDEX_CONSTRAINT_EQ |
| ){ |
| iPlan |= 4; |
| iTopTerm = i; |
| } |
| |
| /* Terms of the form: scope = $scope */ |
| if( (iPlan & 8)==0 |
| && pConstraint->iColumn==6 |
| && pConstraint->op==SQLITE_INDEX_CONSTRAINT_EQ |
| ){ |
| iPlan |= 8; |
| iScopeTerm = i; |
| } |
| } |
| if( iPlan&1 ){ |
| int idx = 2; |
| pIdxInfo->idxNum = iPlan; |
| if( pIdxInfo->nOrderBy==1 |
| && pIdxInfo->aOrderBy[0].iColumn==4 |
| && pIdxInfo->aOrderBy[0].desc==0 |
| ){ |
| pIdxInfo->orderByConsumed = 1; /* Default order by iScore */ |
| } |
| if( iPlan&2 ){ |
| pIdxInfo->aConstraintUsage[iLangTerm].argvIndex = idx++; |
| pIdxInfo->aConstraintUsage[iLangTerm].omit = 1; |
| } |
| if( iPlan&4 ){ |
| pIdxInfo->aConstraintUsage[iTopTerm].argvIndex = idx++; |
| pIdxInfo->aConstraintUsage[iTopTerm].omit = 1; |
| } |
| if( iPlan&8 ){ |
| pIdxInfo->aConstraintUsage[iScopeTerm].argvIndex = idx++; |
| pIdxInfo->aConstraintUsage[iScopeTerm].omit = 1; |
| } |
| pIdxInfo->estimatedCost = (double)10000; |
| }else{ |
| pIdxInfo->idxNum = 0; |
| pIdxInfo->estimatedCost = (double)10000000; |
| } |
| return SQLITE_OK; |
| } |
| |
| /* |
| ** Open a new fuzzy-search cursor. |
| */ |
| static int spellfix1Open(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){ |
| spellfix1_vtab *p = (spellfix1_vtab*)pVTab; |
| spellfix1_cursor *pCur; |
| pCur = sqlite3_malloc( sizeof(*pCur) ); |
| if( pCur==0 ) return SQLITE_NOMEM; |
| memset(pCur, 0, sizeof(*pCur)); |
| pCur->pVTab = p; |
| *ppCursor = &pCur->base; |
| return SQLITE_OK; |
| } |
| |
| /* |
| ** Adjust a distance measurement by the words rank in order to show |
| ** preference to common words. |
| */ |
| static int spellfix1Score(int iDistance, int iRank){ |
| int iLog2; |
| for(iLog2=0; iRank>0; iLog2++, iRank>>=1){} |
| return iDistance + 32 - iLog2; |
| } |
| |
| /* |
| ** Compare two spellfix1_row objects for sorting purposes in qsort() such |
| ** that they sort in order of increasing distance. |
| */ |
| static int spellfix1RowCompare(const void *A, const void *B){ |
| const struct spellfix1_row *a = (const struct spellfix1_row*)A; |
| const struct spellfix1_row *b = (const struct spellfix1_row*)B; |
| return a->iScore - b->iScore; |
| } |
| |
| /* |
| ** This version of the xFilter method work if the MATCH term is present |
| ** and we are doing a scan. |
| */ |
| static int spellfix1FilterForMatch( |
| spellfix1_cursor *pCur, |
| int idxNum, |
| int argc, |
| sqlite3_value **argv |
| ){ |
| const unsigned char *zPatternIn; |
| char *zPattern; |
| int nPattern; |
| char *zClass; |
| int nClass; |
| int iLimit = 20; |
| int iScope = 4; |
| int iLang = 0; |
| char *zSql; |
| int rc; |
| sqlite3_stmt *pStmt; |
| int idx = 1; |
| spellfix1_vtab *p = pCur->pVTab; |
| |
| if( idxNum&2 ){ |
| iLang = sqlite3_value_int(argv[idx++]); |
| } |
| if( idxNum&4 ){ |
| iLimit = sqlite3_value_int(argv[idx++]); |
| if( iLimit<1 ) iLimit = 1; |
| } |
| if( idxNum&8 ){ |
| iScope = sqlite3_value_int(argv[idx++]); |
| if( iScope<1 ) iScope = 1; |
| } |
| spellfix1ResetCursor(pCur, iLimit); |
| zPatternIn = sqlite3_value_text(argv[0]); |
| if( zPatternIn==0 ) return SQLITE_OK; |
| zPattern = (char*)transliterate(zPatternIn, sqlite3_value_bytes(argv[0])); |
| if( zPattern==0 ) return SQLITE_NOMEM; |
| nPattern = strlen(zPattern); |
| if( zPattern[nPattern-1]=='*' ) nPattern--; |
| if( nPattern<iScope ) iScope = nPattern; |
| zClass = (char*)characterClassString((unsigned char*)zPattern, |
| strlen(zPattern)); |
| nClass = strlen(zClass); |
| if( nClass>iScope ){ |
| zClass[iScope] = 0; |
| nClass = iScope; |
| } |
| zSql = sqlite3_mprintf( |
| "SELECT id, word, rank, k1" |
| " FROM \"%w\".\"%w_vocab\"" |
| " WHERE langid=%d AND k2 GLOB '%q*'", |
| p->zDbName, p->zTableName, iLang, zClass |
| ); |
| rc = sqlite3_prepare_v2(p->db, zSql, -1, &pStmt, 0); |
| sqlite3_free(zSql); |
| if( rc==SQLITE_OK ){ |
| const char *zK1; |
| int iDist; |
| int iRank; |
| int iScore; |
| int iWorst = 999999999; |
| int idx; |
| int idxWorst; |
| int i; |
| |
| while( sqlite3_step(pStmt)==SQLITE_ROW ){ |
| zK1 = (const char*)sqlite3_column_text(pStmt, 3); |
| if( zK1==0 ) continue; |
| pCur->nSearch++; |
| iRank = sqlite3_column_int(pStmt, 2); |
| iDist = editdist(zPattern, zK1); |
| iScore = spellfix1Score(iDist,iRank); |
| if( pCur->nRow<pCur->nAlloc ){ |
| idx = pCur->nRow; |
| }else if( iScore<iWorst ){ |
| idx = idxWorst; |
| sqlite3_free(pCur->a[idx].zWord); |
| }else{ |
| continue; |
| } |
| pCur->a[idx].zWord = sqlite3_mprintf("%s", sqlite3_column_text(pStmt, 1)); |
| pCur->a[idx].iRowid = sqlite3_column_int64(pStmt, 0); |
| pCur->a[idx].iRank = iRank; |
| pCur->a[idx].iDistance = iDist; |
| pCur->a[idx].iScore = iScore; |
| if( pCur->nRow<pCur->nAlloc ) pCur->nRow++; |
| if( pCur->nRow==pCur->nAlloc ){ |
| iWorst = pCur->a[0].iScore; |
| idxWorst = 0; |
| for(i=1; i<pCur->nRow; i++){ |
| iScore = pCur->a[i].iScore; |
| if( iWorst<iScore ){ |
| iWorst = iScore; |
| idxWorst = i; |
| } |
| } |
| } |
| } |
| } |
| qsort(pCur->a, pCur->nRow, sizeof(pCur->a[0]), spellfix1RowCompare); |
| pCur->iTop = iLimit; |
| pCur->iScope = iScope; |
| sqlite3_finalize(pStmt); |
| sqlite3_free(zPattern); |
| sqlite3_free(zClass); |
| return SQLITE_OK; |
| } |
| |
| /* |
| ** This version of xFilter handles a full-table scan case |
| */ |
| static int spellfix1FilterForFullScan( |
| spellfix1_cursor *pCur, |
| int idxNum, |
| int argc, |
| sqlite3_value **argv |
| ){ |
| spellfix1ResetCursor(pCur, 0); |
| return SQLITE_OK; |
| } |
| |
| |
| /* |
| ** Called to "rewind" a cursor back to the beginning so that |
| ** it starts its output over again. Always called at least once |
| ** prior to any spellfix1Column, spellfix1Rowid, or spellfix1Eof call. |
| */ |
| static int spellfix1Filter( |
| sqlite3_vtab_cursor *cur, |
| int idxNum, const char *idxStr, |
| int argc, sqlite3_value **argv |
| ){ |
| spellfix1_cursor *pCur = (spellfix1_cursor *)cur; |
| int rc; |
| if( idxNum & 1 ){ |
| rc = spellfix1FilterForMatch(pCur, idxNum, argc, argv); |
| }else{ |
| rc = spellfix1FilterForFullScan(pCur, idxNum, argc, argv); |
| } |
| return rc; |
| } |
| |
| |
| /* |
| ** Advance a cursor to its next row of output |
| */ |
| static int spellfix1Next(sqlite3_vtab_cursor *cur){ |
| spellfix1_cursor *pCur = (spellfix1_cursor *)cur; |
| if( pCur->iRow < pCur->nRow ) pCur->iRow++; |
| return SQLITE_OK; |
| } |
| |
| /* |
| ** Return TRUE if we are at the end-of-file |
| */ |
| static int spellfix1Eof(sqlite3_vtab_cursor *cur){ |
| spellfix1_cursor *pCur = (spellfix1_cursor *)cur; |
| return pCur->iRow>=pCur->nRow; |
| } |
| |
| /* |
| ** Return columns from the current row. |
| */ |
| static int spellfix1Column(sqlite3_vtab_cursor *cur, sqlite3_context *ctx, int i){ |
| spellfix1_cursor *pCur = (spellfix1_cursor*)cur; |
| switch( i ){ |
| case 0: { |
| sqlite3_result_text(ctx, pCur->a[pCur->iRow].zWord, -1, SQLITE_STATIC); |
| break; |
| } |
| case 1: { |
| sqlite3_result_int(ctx, pCur->a[pCur->iRow].iRank); |
| break; |
| } |
| case 2: { |
| sqlite3_result_int(ctx, pCur->a[pCur->iRow].iDistance); |
| break; |
| } |
| case 3: { |
| sqlite3_result_int(ctx, pCur->iLang); |
| break; |
| } |
| case 4: { |
| sqlite3_result_int(ctx, pCur->a[pCur->iRow].iScore); |
| break; |
| } |
| case 5: { |
| sqlite3_result_int(ctx, pCur->iTop); |
| break; |
| } |
| case 6: { |
| sqlite3_result_int(ctx, pCur->iScope); |
| break; |
| } |
| case 7: { |
| sqlite3_result_int(ctx, pCur->nSearch); |
| break; |
| } |
| default: { |
| sqlite3_result_null(ctx); |
| break; |
| } |
| } |
| return SQLITE_OK; |
| } |
| |
| /* |
| ** The rowid. |
| */ |
| static int spellfix1Rowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){ |
| spellfix1_cursor *pCur = (spellfix1_cursor*)cur; |
| *pRowid = pCur->a[pCur->iRow].iRowid; |
| return SQLITE_OK; |
| } |
| |
| /* |
| ** The xUpdate() method. |
| */ |
| static int spellfix1Update( |
| sqlite3_vtab *pVTab, |
| int argc, |
| sqlite3_value **argv, |
| sqlite_int64 *pRowid |
| ){ |
| int rc = SQLITE_OK; |
| sqlite3_int64 rowid, newRowid; |
| spellfix1_vtab *p = (spellfix1_vtab*)pVTab; |
| sqlite3 *db = p->db; |
| |
| if( argc==1 ){ |
| /* A delete operation on the rowid given by argv[0] */ |
| rowid = *pRowid = sqlite3_value_int64(argv[0]); |
| spellfix1DbExec(&rc, db, "DELETE FROM \"%w\".\"%w_vocab\" " |
| " WHERE id=%lld", |
| p->zDbName, p->zTableName, rowid); |
| }else{ |
| const unsigned char *zWord = sqlite3_value_text(argv[2]); |
| int nWord = sqlite3_value_bytes(argv[2]); |
| int iLang = sqlite3_value_int(argv[5]); |
| int iRank = sqlite3_value_int(argv[3]); |
| const unsigned char *zSoundslike = sqlite3_value_text(argv[10]); |
| int nSoundslike = sqlite3_value_bytes(argv[10]); |
| char *zK1, *zK2; |
| int i; |
| char c; |
| |
| if( zWord==0 ){ |
| pVTab->zErrMsg = sqlite3_mprintf("%w.word may not be NULL", |
| p->zTableName); |
| return SQLITE_CONSTRAINT; |
| } |
| if( iRank<1 ) iRank = 1; |
| if( zSoundslike ){ |
| zK1 = (char*)transliterate(zSoundslike, nSoundslike); |
| }else{ |
| zK1 = (char*)transliterate(zWord, nWord); |
| } |
| if( zK1==0 ) return SQLITE_NOMEM; |
| for(i=0; (c = zK1[i])!=0; i++){ |
| if( c>='A' && c<='Z' ) zK1[i] += 'a' - 'A'; |
| } |
| zK2 = (char*)characterClassString((const unsigned char*)zK1, i); |
| if( zK2==0 ){ |
| sqlite3_free(zK1); |
| return SQLITE_NOMEM; |
| } |
| if( sqlite3_value_type(argv[0])==SQLITE_NULL ){ |
| spellfix1DbExec(&rc, db, |
| "INSERT INTO \"%w\".\"%w_vocab\"(rank,langid,word,k1,k2) " |
| "VALUES(%d,%d,%Q,%Q,%Q)", |
| p->zDbName, p->zTableName, |
| iRank, iLang, zWord, zK1, zK2 |
| ); |
| *pRowid = sqlite3_last_insert_rowid(db); |
| }else{ |
| rowid = sqlite3_value_int64(argv[0]); |
| newRowid = *pRowid = sqlite3_value_int64(argv[1]); |
| spellfix1DbExec(&rc, db, |
| "UPDATE \"%w\".\"%w_vocab\" SET id=%lld, rank=%d, lang=%d," |
| " word=%Q, rank=%d, k1=%Q, k2=%Q WHERE id=%lld", |
| p->zDbName, p->zTableName, newRowid, iRank, iLang, |
| zWord, zK1, zK2, rowid |
| ); |
| } |
| sqlite3_free(zK1); |
| sqlite3_free(zK2); |
| } |
| return rc; |
| } |
| |
| /* |
| ** Rename the spellfix1 table. |
| */ |
| static int spellfix1Rename(sqlite3_vtab *pVTab, const char *zNew){ |
| spellfix1_vtab *p = (spellfix1_vtab*)pVTab; |
| sqlite3 *db = p->db; |
| int rc = SQLITE_OK; |
| char *zNewName = sqlite3_mprintf("%s", zNew); |
| if( zNewName==0 ){ |
| return SQLITE_NOMEM; |
| } |
| spellfix1DbExec(&rc, db, |
| "ALTER TABLE \"%w\".\"%w_vocab\" RENAME TO \"%w_vocab\"", |
| p->zDbName, p->zTableName, zNewName |
| ); |
| if( rc==SQLITE_OK ){ |
| sqlite3_free(p->zTableName); |
| p->zTableName = zNewName; |
| } |
| return rc; |
| } |
| |
| |
| /* |
| ** A virtual table module that provides fuzzy search. |
| */ |
| static sqlite3_module spellfix1Module = { |
| 0, /* iVersion */ |
| spellfix1Create, /* xCreate - handle CREATE VIRTUAL TABLE */ |
| spellfix1Connect, /* xConnect - reconnected to an existing table */ |
| spellfix1BestIndex, /* xBestIndex - figure out how to do a query */ |
| spellfix1Disconnect, /* xDisconnect - close a connection */ |
| spellfix1Destroy, /* xDestroy - handle DROP TABLE */ |
| spellfix1Open, /* xOpen - open a cursor */ |
| spellfix1Close, /* xClose - close a cursor */ |
| spellfix1Filter, /* xFilter - configure scan constraints */ |
| spellfix1Next, /* xNext - advance a cursor */ |
| spellfix1Eof, /* xEof - check for end of scan */ |
| spellfix1Column, /* xColumn - read data */ |
| spellfix1Rowid, /* xRowid - read data */ |
| spellfix1Update, /* xUpdate */ |
| 0, /* xBegin */ |
| 0, /* xSync */ |
| 0, /* xCommit */ |
| 0, /* xRollback */ |
| 0, /* xFindMethod */ |
| spellfix1Rename, /* xRename */ |
| }; |
| |
| /* |
| ** Register the various functions and the virtual table. |
| */ |
| static int spellfix1Register(sqlite3 *db){ |
| int nErr = 0; |
| int i; |
| nErr += sqlite3_create_function(db, "spellfix1_translit", 1, SQLITE_UTF8, 0, |
| transliterateSqlFunc, 0, 0); |
| nErr += sqlite3_create_function(db, "spellfix1_editdist", 2, SQLITE_UTF8, 0, |
| editdistSqlFunc, 0, 0); |
| nErr += sqlite3_create_function(db, "spellfix1_charclass", 1, SQLITE_UTF8, 0, |
| characterClassSqlFunc, 0, 0); |
| nErr += sqlite3_create_function(db, "spellfix1_scriptcode", 1, SQLITE_UTF8, 0, |
| scriptCodeSqlFunc, 0, 0); |
| nErr += sqlite3_create_module(db, "spellfix1", &spellfix1Module, 0); |
| |
| /* Verify sanity of the translit[] table */ |
| for(i=0; i<sizeof(translit)/sizeof(translit[0])-1; i++){ |
| assert( translit[i].cFrom<translit[i+1].cFrom ); |
| } |
| |
| return nErr ? SQLITE_ERROR : SQLITE_OK; |
| } |
| |
| #if SQLITE_CORE || defined(SQLITE_TEST) |
| /* |
| ** Register the spellfix1 virtual table and its associated functions. |
| */ |
| int sqlite3Spellfix1Register(sqlite3 *db){ |
| return spellfix1Register(db); |
| } |
| #endif |
| |
| |
| #if !SQLITE_CORE |
| /* |
| ** Extension load function. |
| */ |
| int sqlite3_extension_init( |
| sqlite3 *db, |
| char **pzErrMsg, |
| const sqlite3_api_routines *pApi |
| ){ |
| SQLITE_EXTENSION_INIT2(pApi); |
| return spellfix1Register(db); |
| } |
| #endif /* !SQLITE_CORE */ |