SQLite

      z = z2;
    }
    if( z==0 ) *pRc = SQLITE_NOMEM;
    sqlite3_free(*pz);
    *pz = z;
  }
}

/*
** Return a copy of input string zInput enclosed in double-quotes (") and
** with all double quote characters escaped. For example:
**
**     fts3QuoteId("un \"zip\"")   ->    "un \"\"zip\"\""
**
** The pointer returned points to memory obtained from sqlite3_malloc(). It
** is the callers responsibility to call sqlite3_free() to release this
** memory.
*/
static char *fts3QuoteId(char const *zInput){
  int nRet;
  char *zRet;
  nRet = 2 + strlen(zInput)*2 + 1;
  zRet = sqlite3_malloc(nRet);
  if( zRet ){
    int i;
    char *z = zRet;
    *(z++) = '"';
    for(i=0; zInput[i]; i++){
      if( zInput[i]=='"' ) *(z++) = '"';
      *(z++) = zInput[i];
    }
    *(z++) = '"';
    *(z++) = '\0';
  }
  return zRet;
}

/*
** Return a list of comma separated SQL expressions that could be used
** in a SELECT statement such as the following:
**
**     SELECT <list of expressions> FROM %_content AS x ...
**

** If *pRc is not SQLITE_OK when this function is called, it is a no-op (and
** a NULL pointer is returned). Otherwise, if an OOM error is encountered
** by this function, NULL is returned and *pRc is set to SQLITE_NOMEM. If
** no error occurs, *pRc is left unmodified.
*/
static char *fts3ReadExprList(Fts3Table *p, const char *zFunc, int *pRc){
  char *zRet = 0;
  char *zFree = 0;
  char *zFunction;
  int i;

  if( !zFunc ){
    zFunction = "";
  }else{
    zFree = zFunction = fts3QuoteId(zFunc);
  }
  fts3Appendf(pRc, &zRet, "docid");
  for(i=0; i<p->nColumn; i++){
    fts3Appendf(pRc, &zRet, ",%s(x.'c%d%q')", zFunction, i, p->azColumn[i]);
  }
  sqlite3_free(zFree);
  return zRet;
}

/*
** Return a list of N comma separated question marks, where N is the number
** of columns in the %_content table (one for the docid plus one for each
** user-defined text column).

** If *pRc is not SQLITE_OK when this function is called, it is a no-op (and
** a NULL pointer is returned). Otherwise, if an OOM error is encountered
** by this function, NULL is returned and *pRc is set to SQLITE_NOMEM. If
** no error occurs, *pRc is left unmodified.
*/
static char *fts3WriteExprList(Fts3Table *p, const char *zFunc, int *pRc){
  char *zRet = 0;
  char *zFree = 0;
  char *zFunction;
  int i;

  if( !zFunc ){
    zFunction = "";
  }else{
    zFree = zFunction = fts3QuoteId(zFunc);
  }
  fts3Appendf(pRc, &zRet, "?");
  for(i=0; i<p->nColumn; i++){
    fts3Appendf(pRc, &zRet, ",%s(?)", zFunction);
  }
  sqlite3_free(zFree);
  return zRet;
}

/*
** This function is the implementation of both the xConnect and xCreate
** methods of the FTS3 virtual table.
**

    sqlite3Fts3Dequote(zCsr);
    p->azColumn[iCol] = zCsr;
    zCsr += n+1;
    assert( zCsr <= &((char *)p)[nByte] );
  }

  if( (zCompress==0)!=(zUncompress==0) ){
    char const *zMiss = (zCompress==0 ? "compress" : "uncompress");
    rc = SQLITE_ERROR;
    *pzErr = sqlite3_mprintf("missing %s parameter in fts4 constructor", zMiss);
  }
  p->zReadExprlist = fts3ReadExprList(p, zUncompress, &rc);
  p->zWriteExprlist = fts3WriteExprList(p, zCompress, &rc);
  if( rc!=SQLITE_OK ) goto fts3_init_out;

  /* If this is an xCreate call, create the underlying tables in the 
  ** database. TODO: For xConnect(), it could verify that said tables exist.

#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
ifcapable !fts3 { finish_test ; return }
set ::testprefix fts3comp1

# Create a pretend compression system. 
#
# Each time the [zip] function is called, an entry is added to the ::strings
# array mapping from an integer key to the string argument to zip. The key
# is returned. Later on, when the key is passed to [unzip], the original
# string is retrieved from the ::strings array and returned.
#
set next_x 0
proc zip {x} {
 incr ::next_x
 set ::strings($::next_x) $x
 return $::next_x
}
proc unzip {x} {
  return $::strings($x)
}

foreach {tn zip unzip} {
  1   zip   unzip
  2   {z.i.p!!}    {un "zip"}
} {

  set next_x 0
  catch {db close}
  forcedelete test.db
  sqlite3 db test.db
  db func $zip zip
  db func $unzip unzip
  
  # Create a table that uses zip/unzip. Check that content inserted into
  # the table can be read back (using a full-scan query). Check that the
  # underlying %_content table contains the compressed (integer) values.
  #
  do_execsql_test 1.$tn.0 "
    CREATE VIRTUAL TABLE t1 USING fts4(
      a, b, 
      compress='$zip', uncompress='$unzip'
    );


  "
  do_execsql_test 1.$tn.1 {
    INSERT INTO t1 VALUES('one two three', 'two four six');
    SELECT a, b FROM t1;
  } {{one two three} {two four six}}

  do_execsql_test 1.$tn.2 {
    SELECT c0a, c1b FROM t1_content;
  } {1 2}
  
  # Insert another row and check that it can be read back. Also that the
  # %_content table still contains all compressed content. This time, try
  # full-text index and by-docid queries too.
  #
  do_execsql_test 1.$tn.3 {
    INSERT INTO t1 VALUES('three six nine', 'four eight twelve');
    SELECT a, b FROM t1;
  } {{one two three} {two four six} {three six nine} {four eight twelve}}

  do_execsql_test 1.$tn.4 {
    SELECT c0a, c1b FROM t1_content;
  } {1 2 3 4}
  
  do_execsql_test 1.$tn.5 {
    SELECT a, b FROM t1 WHERE docid = 2
  } {{three six nine} {four eight twelve}}
  do_execsql_test 1.$tn.6 {
    SELECT a, b FROM t1 WHERE t1 MATCH 'two'
  } {{one two three} {two four six}}
  
  # Delete a row and check that the full-text index is correctly updated.
  # Inspect the full-text index using an fts4aux table.
  #
  do_execsql_test 1.$tn.7 {
    CREATE VIRTUAL TABLE terms USING fts4aux(t1);
    SELECT * FROM terms;
  } {
    eight 1 1    four 2 2    nine 1 1    one 1 1 
    six 2 2      three 2 2   twelve 1 1  two 1 2
  }

  do_execsql_test 1.$tn.8 {
    DELETE FROM t1 WHERE docid = 1;
    SELECT * FROM terms;
  } {
    eight 1 1   four 1 1    nine 1 1 
    six 1 1     three 1 1   twelve 1 1
  }
  do_execsql_test 1.$tn.9 { SELECT c0a, c1b FROM t1_content } {3 4}
}

# Test that is an error to specify just one of compress and uncompress.
#
do_catchsql_test 2.1 {

  CREATE VIRTUAL TABLE t2 USING fts4(x, compress=zip)
} {1 {missing uncompress parameter in fts4 constructor}}
do_catchsql_test 2.2 {
  CREATE VIRTUAL TABLE t2 USING fts4(x, uncompress=unzip)
} {1 {missing compress parameter in fts4 constructor}}

finish_test