SQLite

** Synopsis:  r[P3]=r[P2]-r[P1]
**
** Subtract the value in register P1 from the value in register P2
** and store the result in register P3.
** If either input is NULL, the result is NULL.
*/
/* Opcode: Divide P1 P2 P3 * *
** Synopsis:  r[P3]=r[P2]/r[P1]
**
** Divide the value in register P1 by the value in register P2
** and store the result in register P3 (P3=P2/P1). If the value in 
** register P1 is zero, then the result is NULL. If either input is 
** NULL, the result is NULL.
*/
/* Opcode: Remainder P1 P2 P3 * *
** Synopsis:  r[P3]=r[P2]%r[P1]
**
** Compute the remainder after integer register P2 is divided by 
** register P1 and store the result in register P3. 
** If the value in register P1 is zero the result is NULL.
** If either operand is NULL, the result is NULL.
*/
case OP_Add:                   /* same as TK_PLUS, in1, in2, out3 */
case OP_Subtract:              /* same as TK_MINUS, in1, in2, out3 */
case OP_Multiply:              /* same as TK_STAR, in1, in2, out3 */
case OP_Divide:                /* same as TK_SLASH, in1, in2, out3 */
case OP_Remainder: {           /* same as TK_REM, in1, in2, out3 */

**
**     --without-rowid      Use a WITHOUT ROWID table to store the words.
**     --insert             Use INSERT mode (the default)
**     --replace            Use REPLACE mode
**     --select             Use SELECT mode
**     --update             Use UPDATE mode
**     --delete             Use DELETE mode
**     --query              Use QUERY mode
**     --nocase             Add the NOCASE collating sequence to the words.
**     --trace              Enable sqlite3_trace() output.
**     --summary            Show summary information on the collected data.
**     --stats              Show sqlite3_status() results at the end.
**     --pagesize NNN       Use a page size of NNN
**     --cachesize NNN      Use a cache size of NNN
**     --commit NNN         Commit after every NNN operations

**    (1) SELECT 1 FROM wordcount WHERE word=$new
**    (2) INSERT INTO wordcount VALUES($new,1) -- if (1) returns nothing
**    (3) UPDATE wordcount SET cnt=cnt+1 WHERE word=$new  --if (1) return TRUE
**
** Delete mode means:
**    (1) DELETE FROM wordcount WHERE word=$new
**
** Query mode means:
**    (1) SELECT cnt FROM wordcount WHERE word=$new
**
** Note that delete mode and query mode are only useful for preexisting
** databases.  The wordcount table is created using IF NOT EXISTS so this
** utility can be run multiple times on the same database file.  The
** --without-rowid, --nocase, and --pagesize parameters are only effective
** when creating a new database and are harmless no-ops on preexisting
** databases.
**
******************************************************************************
**
** Compile as follows:
**
**    gcc -I. wordcount.c sqlite3.c -ldl -lpthreads
**

/* Define operating modes */
#define MODE_INSERT     0
#define MODE_REPLACE    1
#define MODE_SELECT     2
#define MODE_UPDATE     3
#define MODE_DELETE     4
#define MODE_QUERY      5

int main(int argc, char **argv){
  const char *zFileToRead = 0;  /* Input file.  NULL for stdin */
  const char *zDbName = 0;      /* Name of the database file to create */
  int useWithoutRowid = 0;      /* True for --without-rowid */
  int iMode = MODE_INSERT;      /* One of MODE_xxxxx */
  int useNocase = 0;            /* True for --nocase */

  sqlite3_stmt *pInsert = 0;    /* The INSERT statement */
  sqlite3_stmt *pUpdate = 0;    /* The UPDATE statement */
  sqlite3_stmt *pSelect = 0;    /* The SELECT statement */
  sqlite3_stmt *pDelete = 0;    /* The DELETE statement */
  FILE *in;                     /* The open input file */
  int rc;                       /* Return code from an SQLite interface */
  int iCur, iHiwtr;             /* Statistics values, current and "highwater" */
  sqlite3_int64 sumCnt = 0;     /* Sum in QUERY mode */
  char zInput[2000];            /* A single line of input */

  /* Process command-line arguments */
  for(i=1; i<argc; i++){
    const char *z = argv[i];
    if( z[0]=='-' ){
      do{ z++; }while( z[0]=='-' );
      if( strcmp(z,"without-rowid")==0 ){
        useWithoutRowid = 1;
      }else if( strcmp(z,"replace")==0 ){
        iMode = MODE_REPLACE;
      }else if( strcmp(z,"select")==0 ){
        iMode = MODE_SELECT;
      }else if( strcmp(z,"insert")==0 ){
        iMode = MODE_INSERT;
      }else if( strcmp(z,"update")==0 ){
        iMode = MODE_UPDATE;
      }else if( strcmp(z,"delete")==0 ){
        iMode = MODE_DELETE;
      }else if( strcmp(z,"query")==0 ){
        iMode = MODE_QUERY;
      }else if( strcmp(z,"nocase")==0 ){
        useNocase = 1;
      }else if( strcmp(z,"trace")==0 ){
        doTrace = 1;
      }else if( strcmp(z,"nosync")==0 ){
        noSync = 1;
      }else if( strcmp(z,"stats")==0 ){

  if( zSql==0 ) fatal_error("out of memory\n");
  rc = sqlite3_exec(db, zSql, 0, 0, 0);
  if( rc ) fatal_error("Could not create the wordcount table: %s.\n",
                       sqlite3_errmsg(db));
  sqlite3_free(zSql);

  /* Prepare SQL statements that will be needed */
  if( iMode==MODE_QUERY ){
    rc = sqlite3_prepare_v2(db,
          "SELECT cnt FROM wordcount WHERE word=?1",
          -1, &pSelect, 0);
    if( rc ) fatal_error("Could not prepare the SELECT statement: %s\n",
                          sqlite3_errmsg(db));
  }
  if( iMode==MODE_SELECT ){
    rc = sqlite3_prepare_v2(db,
          "SELECT 1 FROM wordcount WHERE word=?1",
          -1, &pSelect, 0);
    if( rc ) fatal_error("Could not prepare the SELECT statement: %s\n",
                          sqlite3_errmsg(db));
    rc = sqlite3_prepare_v2(db,

          if( sqlite3_step(pInsert)!=SQLITE_DONE ){
            fatal_error("Insert failed: %s\n", sqlite3_errmsg(db));
          }
          sqlite3_reset(pInsert);
        }else{
          fatal_error("SELECT failed: %s\n", sqlite3_errmsg(db));
        }
      }else if( iMode==MODE_QUERY ){
        sqlite3_bind_text(pSelect, 1, zInput+i, j-i, SQLITE_STATIC);
        if( sqlite3_step(pSelect)==SQLITE_ROW ){
          sumCnt += sqlite3_column_int64(pSelect, 0);
        }
        sqlite3_reset(pSelect);
      }else{
        sqlite3_bind_text(pInsert, 1, zInput+i, j-i, SQLITE_STATIC);
        if( sqlite3_step(pInsert)!=SQLITE_DONE ){
          fatal_error("INSERT failed: %s\n", sqlite3_errmsg(db));
        }
        sqlite3_reset(pInsert);
        if( iMode==MODE_UPDATE

  }
  sqlite3_exec(db, "COMMIT", 0, 0, 0);
  if( zFileToRead ) fclose(in);
  sqlite3_finalize(pInsert);
  sqlite3_finalize(pUpdate);
  sqlite3_finalize(pSelect);
  sqlite3_finalize(pDelete);

  if( iMode==MODE_QUERY ){
    printf("sum of cnt: %lld\n", sumCnt);
    rc = sqlite3_prepare_v2(db,"SELECT sum(cnt*cnt) FROM wordcount", -1,
                            &pSelect, 0);
    if( rc==SQLITE_OK && sqlite3_step(pSelect)==SQLITE_ROW ){
      printf("double-check: %lld\n", sqlite3_column_int64(pSelect, 0));
    }
    sqlite3_finalize(pSelect);
  }

  if( showSummary ){
    sqlite3_create_function(db, "checksum", -1, SQLITE_UTF8, 0,
                            0, checksumStep, checksumFinalize);
    sqlite3_exec(db, 
      "SELECT 'count(*):  ', count(*) FROM wordcount;\n"
      "SELECT 'sum(cnt):  ', sum(cnt) FROM wordcount;\n"