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Overview
Comment:Add the columns=N parameter to the CSV extension.
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SHA1: 28ebeadd6a4c9ff2ce9fc86a0f0fe2f6cf94d3ac
User & Date: drh 2016-05-31 18:44:33
Context
2016-06-01
05:02
Fix compilation issues with the VFS stat extension. check-in: f6e95652 user: mistachkin tags: trunk
2016-05-31
21:18
An experimental branch with code that allows virtual tables to be declared as WITHOUT ROWID tables. This might be useful for virtual tables that model external data sources that do not have a convenient way of computing a unique rowid. The current check-in almost works, but there are still serious issues. check-in: 49638f18 user: drh tags: without-rowid-vtab
18:44
Add the columns=N parameter to the CSV extension. check-in: 28ebeadd user: drh tags: trunk
18:08
Add the testflags parameter to the csv extension. check-in: b93fb2fe user: drh tags: trunk
Changes
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Changes to ext/misc/csv.c.

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  return -1;
}


/*
** Parameters:
**    filename=FILENAME          Required
**    schema=SCHEMA              Optional
**    header=YES|NO              First row of CSV defines the names of
**                               columns if "yes".  Default "no".

**    testflags=N                Bitmask of test flags.  Optional
**
** If header=no and not columns are listed, then the columns are named
** "c0", "c1", "c2", and so forth.



*/
static int csvtabConnect(
  sqlite3 *db,
  void *pAux,
  int argc, const char *const*argv,
  sqlite3_vtab **ppVtab,
  char **pzErr
){
  CsvTable *pNew = 0;
  int bHeader = -1;
  int rc = SQLITE_OK;
  int i;
  char *zFilename = 0;
  char *zSchema = 0;
  int tstFlags = 0;
  CsvReader sRdr;



  memset(&sRdr, 0, sizeof(sRdr));
  for(i=3; i<argc; i++){
    const char *z = argv[i];
    const char *zValue;
    if( (zValue = csv_parameter("filename",8,z))!=0 ){
      if( zFilename ){
................................................................................
        csv_errmsg(&sRdr, "unrecognized argument to 'header': %s", zValue);
        goto csvtab_connect_error;
      }
    }else
    if( (zValue = csv_parameter("testflags",9,z))!=0 ){
      tstFlags = (unsigned int)atoi(zValue);
    }else











    {
      csv_errmsg(&sRdr, "unrecognized parameter '%s'", z);
      goto csvtab_connect_error;
    }
  }
  if( zFilename==0 ){
    csv_errmsg(&sRdr, "missing 'filename' parameter");
    goto csvtab_connect_error;
  }
  if( csv_reader_open(&sRdr, zFilename) ){
    goto csvtab_connect_error;
  }
  pNew = sqlite3_malloc( sizeof(*pNew) );
  *ppVtab = (sqlite3_vtab*)pNew;
  if( pNew==0 ) goto csvtab_connect_oom;
  memset(pNew, 0, sizeof(*pNew));



  do{
    const char *z = csv_read_one_field(&sRdr);
    if( z==0 ) goto csvtab_connect_oom;
    pNew->nCol++;
  }while( sRdr.cTerm==',' );

  pNew->zFilename = zFilename;
  pNew->tstFlags = tstFlags;
  zFilename = 0;
  pNew->iStart = bHeader==1 ? ftell(sRdr.in) : 0;
  csv_reader_reset(&sRdr);
  if( zSchema==0 ){
    char *zSep = "";
................................................................................
*/
static int csvtabBestIndex(
  sqlite3_vtab *tab,
  sqlite3_index_info *pIdxInfo
){
  CsvTable *pTab = (CsvTable*)tab;
  int i;

  pIdxInfo->estimatedCost = 1000000;
  if( (pTab->tstFlags & CSVTEST_FIDX)==0 ){
    return SQLITE_OK;
  }




  for(i=0; i<pIdxInfo->nConstraint; i++){

    if( pIdxInfo->aConstraint[i].usable==0 ) continue;

    if( pIdxInfo->aConstraint[i].op==SQLITE_INDEX_CONSTRAINT_EQ ){



      pIdxInfo->estimatedCost = 10;
      break;


    }
  }
  return SQLITE_OK;
}


static sqlite3_module CsvModule = {







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  return -1;
}


/*
** Parameters:
**    filename=FILENAME          Required
**    schema=SCHEMA              Alternative CSV schema.
**    header=YES|NO              First row of CSV defines the names of
**                               columns if "yes".  Default "no".
**    columns=N                  Assum the CSV file contains N columns.
**    testflags=N                Bitmask of test flags.  Optional
**
** If schema= is omitted, then the columns are named "c0", "c1", "c2",

** and so forth.  If columns=N is omitted, then the file is opened and
** the number of columns in the first row is counted to determine the
** column count.  If header=YES, then the first row is skipped.
*/
static int csvtabConnect(
  sqlite3 *db,
  void *pAux,
  int argc, const char *const*argv,
  sqlite3_vtab **ppVtab,
  char **pzErr
){
  CsvTable *pNew = 0;        /* The CsvTable object to construct */
  int bHeader = -1;          /* header= flags.  -1 means not seen yet */
  int rc = SQLITE_OK;        /* Result code from this routine */
  int i;                     /* Loop counter */
  char *zFilename = 0;       /* Value of the filename= parameter */
  char *zSchema = 0;         /* Value of the schema= parameter */
  int tstFlags = 0;          /* Value of the testflags= parameter */
  int nCol = -99;            /* Value of the columns= parameter */
  CsvReader sRdr;            /* A CSV file reader used to store an error
                             ** message and/or to count the number of columns */

  memset(&sRdr, 0, sizeof(sRdr));
  for(i=3; i<argc; i++){
    const char *z = argv[i];
    const char *zValue;
    if( (zValue = csv_parameter("filename",8,z))!=0 ){
      if( zFilename ){
................................................................................
        csv_errmsg(&sRdr, "unrecognized argument to 'header': %s", zValue);
        goto csvtab_connect_error;
      }
    }else
    if( (zValue = csv_parameter("testflags",9,z))!=0 ){
      tstFlags = (unsigned int)atoi(zValue);
    }else
    if( (zValue = csv_parameter("columns",7,z))!=0 ){
      if( nCol>0 ){
        csv_errmsg(&sRdr, "more than one 'columns' parameter");
        goto csvtab_connect_error;
      }
      nCol = atoi(zValue);
      if( nCol<=0 ){
        csv_errmsg(&sRdr, "must have at least one column");
        goto csvtab_connect_error;
      }
    }else
    {
      csv_errmsg(&sRdr, "unrecognized parameter '%s'", z);
      goto csvtab_connect_error;
    }
  }
  if( zFilename==0 ){
    csv_errmsg(&sRdr, "missing 'filename' parameter");
    goto csvtab_connect_error;
  }
  if( nCol<=0 && csv_reader_open(&sRdr, zFilename) ){
    goto csvtab_connect_error;
  }
  pNew = sqlite3_malloc( sizeof(*pNew) );
  *ppVtab = (sqlite3_vtab*)pNew;
  if( pNew==0 ) goto csvtab_connect_oom;
  memset(pNew, 0, sizeof(*pNew));
  if( nCol>0 ){
    pNew->nCol = nCol;
  }else{
    do{
      const char *z = csv_read_one_field(&sRdr);
      if( z==0 ) goto csvtab_connect_oom;
      pNew->nCol++;
    }while( sRdr.cTerm==',' );
  }
  pNew->zFilename = zFilename;
  pNew->tstFlags = tstFlags;
  zFilename = 0;
  pNew->iStart = bHeader==1 ? ftell(sRdr.in) : 0;
  csv_reader_reset(&sRdr);
  if( zSchema==0 ){
    char *zSep = "";
................................................................................
*/
static int csvtabBestIndex(
  sqlite3_vtab *tab,
  sqlite3_index_info *pIdxInfo
){
  CsvTable *pTab = (CsvTable*)tab;
  int i;
  int nConst = 0;
  pIdxInfo->estimatedCost = 1000000;
  if( (pTab->tstFlags & CSVTEST_FIDX)==0 ){
    return SQLITE_OK;
  }
  /* The usual (an sensible) case is to take the "return SQLITE_OK" above.
  ** The code below only runs when testflags=1.  The following code
  ** generates an artifical and unrealistic plan which is useful
  ** for testing virtual table logic but is useless for real applications. */
  for(i=0; i<pIdxInfo->nConstraint; i++){
    unsigned char op;
    if( pIdxInfo->aConstraint[i].usable==0 ) continue;
    op = pIdxInfo->aConstraint[i].op;
    if( op==SQLITE_INDEX_CONSTRAINT_EQ 
     || op==SQLITE_INDEX_CONSTRAINT_LIKE
     || op==SQLITE_INDEX_CONSTRAINT_GLOB
    ){
      pIdxInfo->estimatedCost = 10;

      pIdxInfo->aConstraintUsage[nConst].argvIndex = nConst+1;
      nConst++;
    }
  }
  return SQLITE_OK;
}


static sqlite3_module CsvModule = {