Lift code to traverse interior nodes out of loadSegment().

Refactoring towards prefix searching. (CVS 3882)

FossilOrigin-Name: 25935db73877c0cb132acb30c2fed2544d0e5e32

ext/fts2/fts2.c

@@ -5137,6 +5137,30 @@ static int loadSegmentLeaf(fulltext_vtab *v, const char *pData, int nData,
   return rc;
 }
 
+/* Taking pData/nData as an interior node, find the child node which
+** could include pTerm/nTerm.  Note that the interior node terms
+** logically come between the blocks, so there is one more blockid
+** than there are terms (that block contains terms >= the last
+** interior-node term).
+*/
+static void getNextChild(const char *pData, int nData,
+                         const char *pTerm, int nTerm,
+                         sqlite_int64 *piBlockid){
+  InteriorReader reader;
+
+  assert( nData>1 );
+  assert( *pData!='\0' );
+  interiorReaderInit(pData, nData, &reader);
+
+  while( !interiorReaderAtEnd(&reader) ){
+    if( interiorReaderTermCmp(&reader, pTerm, nTerm)>0 ) break;
+    interiorReaderStep(&reader);
+  }
+  *piBlockid = interiorReaderCurrentBlockid(&reader);
+
+  interiorReaderDestroy(&reader);
+}
+
 /* Traverse the tree represented by pData[nData] looking for
 ** pTerm[nTerm], merging its doclist over *out if found (any duplicate
 ** doclists read from the segment rooted at pData will overwrite those
@@ -5155,24 +5179,7 @@ static int loadSegment(fulltext_vtab *v, const char *pData, int nData,
   /* Process data as an interior node until we reach a leaf. */
   while( *pData!='\0' ){
     sqlite_int64 iBlockid;
-    InteriorReader reader;
-
-    /* Scan the node data until we find a term greater than our term.
-    ** Our target child will be in the blockid under that term, or in
-    ** the last blockid in the node if we never find such a term.
-    */
-    interiorReaderInit(pData, nData, &reader);
-    while( !interiorReaderAtEnd(&reader) ){
-      if( interiorReaderTermCmp(&reader, pTerm, nTerm)>0 ) break;
-      interiorReaderStep(&reader);
-    }
-
-    /* Grab the child blockid before calling sql_get_statement(),
-    ** because sql_get_statement() may reset our data out from under
-    ** us.
-    */
-    iBlockid = interiorReaderCurrentBlockid(&reader);
-    interiorReaderDestroy(&reader);
+    getNextChild(pData, nData, pTerm, nTerm, &iBlockid);
 
     rc = sql_get_statement(v, BLOCK_SELECT_STMT, &s);
     if( rc!=SQLITE_OK ) return rc;

manifest

@@ -1,5 +1,5 @@
-C Refactor\sfts2\sloadSegmentLeaf()\sin\spreparation\sfor\sprefix-searching.\nPrefix-searching\swill\swant\sto\saccumulate\sdata\sacross\smultiple\sleaves\nin\sthe\ssegment,\susing\sLeavesReader\sinstead\sof\sLeafReader\sis\sthe\sfirst\nstep\sin\sthat\sdirection.\s(CVS\s3881)
-D 2007-04-27T21:02:00
+C Lift\scode\sto\straverse\sinterior\snodes\sout\sof\sloadSegment().\nRefactoring\stowards\sprefix\ssearching.\s(CVS\s3882)
+D 2007-04-27T21:24:18
 F Makefile.in 8cab54f7c9f5af8f22fd97ddf1ecfd1e1860de62
 F Makefile.linux-gcc 2d8574d1ba75f129aba2019f0b959db380a90935
 F README 9c4e2d6706bdcc3efdd773ce752a8cdab4f90028
@@ -34,7 +34,7 @@ F ext/fts1/fulltext.h 08525a47852d1d62a0be81d3fc3fe2d23b094efd
 F ext/fts1/simple_tokenizer.c 1844d72f7194c3fd3d7e4173053911bf0661b70d
 F ext/fts1/tokenizer.h 0c53421b832366d20d720d21ea3e1f6e66a36ef9
 F ext/fts2/README.txt 8c18f41574404623b76917b9da66fcb0ab38328d
-F ext/fts2/fts2.c 430ef1093f23691604fb6648c280159bc4465d74
+F ext/fts2/fts2.c c1e7528d9f49f1c982bb0b75f262b115a508d140
 F ext/fts2/fts2.h 591916a822cfb6426518fdbf6069359119bc46eb
 F ext/fts2/fts2_hash.c b3f22116d4ef0bc8f2da6e3fdc435c86d0951a9b
 F ext/fts2/fts2_hash.h e283308156018329f042816eb09334df714e105e
@@ -464,7 +464,7 @@ F www/tclsqlite.tcl bb0d1357328a42b1993d78573e587c6dcbc964b9
 F www/vdbe.tcl 87a31ace769f20d3627a64fa1fade7fed47b90d0
 F www/version3.tcl 890248cf7b70e60c383b0e84d77d5132b3ead42b
 F www/whentouse.tcl fc46eae081251c3c181bd79c5faef8195d7991a5
-P e92bd97a3726bbb7978489e2994747127c4aefcf
-R 5fb6880a5d72930ca95c09c7065e68ee
+P 22ffdae4b6f3d0ea584dafa5268af7aa6fdcdc6e
+R dce6a390ff9ccb534e4d5743da453b5a
 U shess
-Z b6beaad154ccbe5f20864433f88b3cb0
+Z 3d1f65a5bd747e5ae2188d3aea41ae85

manifest.uuid

@@ -1 +1 @@
-22ffdae4b6f3d0ea584dafa5268af7aa6fdcdc6e
+25935db73877c0cb132acb30c2fed2544d0e5e32