Add the "remove_diacritics" option to the fts5 trigram tokenizer.

FossilOrigin-Name: 83da80135b6105f47d1de560232449562ae8ac176c8011a6f75589f62bc9b1db

ext/fts5/fts5_tokenize.c

@@ -227,6 +227,12 @@ static const unsigned char sqlite3Utf8Trans1[] = {
   }                                                    \
 }
 
+#define SKIP_UTF8(zIn) {                               \
+  if( ((unsigned char)(*(zIn++)))>=0xc0 ){                              \
+    while( (((unsigned char)*zIn) & 0xc0)==0x80 ){ zIn++; }             \
+  }                                                    \
+}
+
 #endif /* ifndef SQLITE_AMALGAMATION */
 
 typedef struct Unicode61Tokenizer Unicode61Tokenizer;
@@ -1264,6 +1270,7 @@ static int fts5PorterTokenize(
 typedef struct TrigramTokenizer TrigramTokenizer;
 struct TrigramTokenizer {
   int bFold;                      /* True to fold to lower-case */
+  int iFoldParam;                 /* Parameter to pass to Fts5UnicodeFold() */
 };
 
 /*
@@ -1298,10 +1305,21 @@ static int fts5TriCreate(
         }else{
           pNew->bFold = (zArg[0]=='0');
         }
+      }else if( 0==sqlite3_stricmp(azArg[i], "remove_diacritics") ){
+        if( (zArg[0]!='0' && zArg[0]!='1' && zArg[0]!='2') || zArg[1] ){
+          rc = SQLITE_ERROR;
+        }else{
+          pNew->iFoldParam = (zArg[0]!='0') ? 2 : 0;
+        }
       }else{
         rc = SQLITE_ERROR;
       }
     }
+
+    if( pNew->iFoldParam!=0 && pNew->bFold==0 ){
+      rc = SQLITE_ERROR;
+    }
+
     if( rc!=SQLITE_OK ){
       fts5TriDelete((Fts5Tokenizer*)pNew);
       pNew = 0;
@@ -1324,40 +1342,62 @@ static int fts5TriTokenize(
   TrigramTokenizer *p = (TrigramTokenizer*)pTok;
   int rc = SQLITE_OK;
   char aBuf[32];
+  char *zOut = aBuf;
+  int ii;
   const unsigned char *zIn = (const unsigned char*)pText;
   const unsigned char *zEof = &zIn[nText];
   u32 iCode;
+  int aStart[3];                  /* Input offset of each character in aBuf[] */
 
   UNUSED_PARAM(unusedFlags);
-  while( 1 ){
-    char *zOut = aBuf;
-    int iStart = zIn - (const unsigned char*)pText;
-    const unsigned char *zNext; 
 
-    READ_UTF8(zIn, zEof, iCode);
-    if( iCode==0 ) break;
-    zNext = zIn;
-    if( zIn<zEof ){
-      if( p->bFold ) iCode = sqlite3Fts5UnicodeFold(iCode, 0);
-      WRITE_UTF8(zOut, iCode);
+  /* Populate aBuf[] with the characters for the first trigram. */
+  for(ii=0; ii<3; ii++){
+    do {
+      aStart[ii] = zIn - (const unsigned char*)pText;
+      READ_UTF8(zIn, zEof, iCode);
+      if( iCode==0 ) return SQLITE_OK;
+      if( p->bFold ) iCode = sqlite3Fts5UnicodeFold(iCode, p->iFoldParam);
+    }while( iCode==0 );
+    WRITE_UTF8(zOut, iCode);
+  }
+
+  /* At the start of each iteration of this loop:
+  **
+  **  aBuf:      Contains 3 characters. The 3 characters of the next trigram.
+  **  zOut:      Points to the byte following the last character in aBuf.
+  **  aStart[3]: Contains the byte offset in the input text corresponding
+  **             to the start of each of the three characters in the buffer.
+  */
+  assert( zIn<=zEof );
+  while( 1 ){
+    int iNext;                    /* Start of character following current tri */
+    const char *z1;
+
+    /* Read characters from the input up until the first non-diacritic */
+    do {
+      iNext = zIn - (const unsigned char*)pText;
       READ_UTF8(zIn, zEof, iCode);
       if( iCode==0 ) break;
-    }else{
-      break;
-    }
-    if( zIn<zEof ){
-      if( p->bFold ) iCode = sqlite3Fts5UnicodeFold(iCode, 0);
-      WRITE_UTF8(zOut, iCode);
-      READ_UTF8(zIn, zEof, iCode);
-      if( iCode==0 ) break;
-      if( p->bFold ) iCode = sqlite3Fts5UnicodeFold(iCode, 0);
-      WRITE_UTF8(zOut, iCode);
-    }else{
-      break;
-    }
-    rc = xToken(pCtx, 0, aBuf, zOut-aBuf, iStart, iStart + zOut-aBuf);
-    if( rc!=SQLITE_OK ) break;
-    zIn = zNext;
+      if( p->bFold ) iCode = sqlite3Fts5UnicodeFold(iCode, p->iFoldParam);
+    }while( iCode==0 );
+
+    /* Pass the current trigram back to fts5 */
+    rc = xToken(pCtx, 0, aBuf, zOut-aBuf, aStart[0], iNext);
+    if( iCode==0 || rc!=SQLITE_OK ) break;
+
+    /* Remove the first character from buffer aBuf[]. Append the character
+    ** with codepoint iCode.  */
+    z1 = aBuf;
+    SKIP_UTF8(z1);
+    memmove(aBuf, z1, zOut - z1);
+    zOut -= (z1 - aBuf);
+    WRITE_UTF8(zOut, iCode);
+
+    /* Update the aStart[] array */
+    aStart[0] = aStart[1];
+    aStart[1] = aStart[2];
+    aStart[2] = iNext;
   }
 
   return rc;
@@ -1380,7 +1420,9 @@ int sqlite3Fts5TokenizerPattern(
 ){
   if( xCreate==fts5TriCreate ){
     TrigramTokenizer *p = (TrigramTokenizer*)pTok;
-    return p->bFold ? FTS5_PATTERN_LIKE : FTS5_PATTERN_GLOB;
+    if( p->iFoldParam==0 ){
+      return p->bFold ? FTS5_PATTERN_LIKE : FTS5_PATTERN_GLOB;
+    }
   }
   return FTS5_PATTERN_NONE;
 }

ext/fts5/test/fts5trigram2.test

@@ -0,0 +1,109 @@
+# 2023 October 24
+#
+# 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.
+#
+#*************************************************************************
+#
+# Tests for the fts5 "trigram" tokenizer.
+#
+
+source [file join [file dirname [info script]] fts5_common.tcl]
+ifcapable !fts5 { finish_test ; return }
+set ::testprefix fts5trigram2
+
+do_execsql_test 1.0 "
+  CREATE VIRTUAL TABLE t1 USING fts5(y, tokenize='trigram remove_diacritics 1');
+  INSERT INTO t1 VALUES('abc\u0303defghijklm');
+  INSERT INTO t1 VALUES('a\u0303b\u0303c\u0303defghijklm');
+"
+
+do_execsql_test 1.1 {
+  SELECT highlight(t1, 0, '(', ')') FROM t1('abc');
+} [list \
+  "(abc\u0303)defghijklm"                          \
+  "(a\u0303b\u0303c\u0303)defghijklm"              \
+]
+
+do_execsql_test 1.2 {
+  SELECT highlight(t1, 0, '(', ')') FROM t1('bcde');
+} [list \
+  "a(bc\u0303de)fghijklm"                          \
+  "a\u0303(b\u0303c\u0303de)fghijklm"              \
+]
+
+do_execsql_test 1.3 {
+  SELECT highlight(t1, 0, '(', ')') FROM t1('cdef');
+} [list \
+  "ab(c\u0303def)ghijklm"                          \
+  "a\u0303b\u0303(c\u0303def)ghijklm"              \
+]
+
+do_execsql_test 1.4 {
+  SELECT highlight(t1, 0, '(', ')') FROM t1('def');
+} [list \
+  "abc\u0303(def)ghijklm"                          \
+  "a\u0303b\u0303c\u0303(def)ghijklm"              \
+]
+
+
+#-------------------------------------------------------------------------
+do_catchsql_test 2.0 {
+  CREATE VIRTUAL TABLE t2 USING fts5(
+      z, tokenize='trigram case_sensitive 1 remove_diacritics 1'
+  );
+} {1 {error in tokenizer constructor}}
+
+do_execsql_test 2.1 {
+  CREATE VIRTUAL TABLE t2 USING fts5(
+      z, tokenize='trigram case_sensitive 0 remove_diacritics 1'
+  );
+}
+do_execsql_test 2.2 "
+  INSERT INTO t2 VALUES('\u00E3bcdef');
+  INSERT INTO t2 VALUES('b\u00E3cdef');
+  INSERT INTO t2 VALUES('bc\u00E3def');
+  INSERT INTO t2 VALUES('bcd\u00E3ef');
+"
+
+do_execsql_test 2.3 {
+  SELECT highlight(t2, 0, '(', ')') FROM t2('abc');
+} "(\u00E3bc)def"
+do_execsql_test 2.4 {
+  SELECT highlight(t2, 0, '(', ')') FROM t2('bac');
+} "(b\u00E3c)def"
+do_execsql_test 2.5 {
+  SELECT highlight(t2, 0, '(', ')') FROM t2('bca');
+} "(bc\u00E3)def"
+do_execsql_test 2.6 "
+  SELECT highlight(t2, 0, '(', ')') FROM t2('\u00E3bc');
+" "(\u00E3bc)def"
+
+#-------------------------------------------------------------------------
+do_execsql_test 3.0 {
+  CREATE VIRTUAL TABLE t3 USING fts5(
+      z, tokenize='trigram remove_diacritics 1'
+  );
+} {}
+do_execsql_test 3.1 "
+  INSERT INTO t3 VALUES ('\u0303abc\u0303');
+"
+do_execsql_test 3.2 {
+  SELECT highlight(t3, 0, '(', ')') FROM t3('abc');
+} "\u0303(abc\u0303)"
+
+#-------------------------------------------------------------------------
+do_execsql_test 4.0 {
+  CREATE VIRTUAL TABLE t4 USING fts5(z, tokenize=trigram);
+} {}
+
+breakpoint
+do_execsql_test 4.1 {
+  INSERT INTO t4 VALUES('ABCD');
+} {}
+
+finish_test

manifest

@@ -1,5 +1,5 @@
-C One\smore\stweak\sto\stool/srctree-check.tcl\sso\sthat\sa\scomplete\sbuild\scan\sbe\naccomplished\sfrom\sa\sread-only\ssource\stree.
-D 2023-11-02T13:10:16.285
+C Add\sthe\s"remove_diacritics"\soption\sto\sthe\sfts5\strigram\stokenizer.
+D 2023-11-02T17:31:06.153
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -100,7 +100,7 @@ F ext/fts5/fts5_storage.c 5d10b9bdcce5b90656cad13c7d12ad4148677d4b9e3fca0481fca5
 F ext/fts5/fts5_tcl.c b1445cbe69908c411df8084a10b2485500ac70a9c747cdc8cda175a3da59d8ae
 F ext/fts5/fts5_test_mi.c 08c11ec968148d4cb4119d96d819f8c1f329812c568bac3684f5464be177d3ee
 F ext/fts5/fts5_test_tok.c 3cb0a9b508b30d17ef025ccddd26ae3dc8ddffbe76c057616e59a9aa85d36f3b
-F ext/fts5/fts5_tokenize.c 5e251efb0f1af99a25ed50010ba6b1ad1250aca5921af1988fdcabe5ebc3cb43
+F ext/fts5/fts5_tokenize.c 5a895f3bf366a87cb8c0812445736248c236e7ea664a10125021662acd6b0ba4
 F ext/fts5/fts5_unicode2.c eca63dbc797f8ff0572e97caf4631389c0ab900d6364861b915bdd4735973f00
 F ext/fts5/fts5_varint.c e64d2113f6e1bfee0032972cffc1207b77af63319746951bf1d09885d1dadf80
 F ext/fts5/fts5_vocab.c aed56169ae5c1aa9b8189c779ffeef04ed516d3c712c06914e6d91a6759f4e4a
@@ -217,6 +217,7 @@ F ext/fts5/test/fts5tok1.test 1f7817499f5971450d8c4a652114b3d833393c8134e32422d0
 F ext/fts5/test/fts5tok2.test dcacb32d4a2a3f0dd3215d4a3987f78ae4be21a2
 F ext/fts5/test/fts5tokenizer.test ac3c9112b263a639fb0508ae73a3ee886bf4866d2153771a8e8a20c721305a43
 F ext/fts5/test/fts5trigram.test 6c4e37864f3e7d90673db5563d9736d7e40080ab94d10ebdffa94c1b77941da0
+F ext/fts5/test/fts5trigram2.test 9fe4207f8a4241747aff1005258b564958588d21bfd240d6cd4c2e955d31c156
 F ext/fts5/test/fts5ubsan.test 783d5a8d13ebfa169e634940228db54540780e3ba7a87ad1e4510e61440bf64b
 F ext/fts5/test/fts5umlaut.test a42fe2fe6387c40c49ab27ccbd070e1ae38e07f38d05926482cc0bccac9ad602
 F ext/fts5/test/fts5unicode.test 17056f4efe6b0a5d4f41fdf7a7dc9af2873004562eaa899d40633b93dc95f5a9
@@ -2139,8 +2140,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
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-U drh
-Z 72328c40506425c913ea7fab75e23b19
+P cba9f0601ca995ac6952aa3a83f7264f6d25aaaa2ea36b19e90cbf591077de72
+R 91c6db43050bc1c48384df29a062813f
+U dan
+Z e9e46724e46ba97d1a7a1bb71106fcd0
 # Remove this line to create a well-formed Fossil manifest.

manifest.uuid

@@ -1 +1 @@
-cba9f0601ca995ac6952aa3a83f7264f6d25aaaa2ea36b19e90cbf591077de72
+83da80135b6105f47d1de560232449562ae8ac176c8011a6f75589f62bc9b1db