SQLite

** Option:
**
**     --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
**     --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
**     --nosync             Use PRAGMA synchronous=OFF
**     --journal MMMM       Use PRAGMA journal_mode=MMMM
**
** Modes:
**
** Insert mode means:
**    (1) INSERT OR IGNORE INTO wordcount VALUES($new,1)
**    (2) UPDATE wordcount SET cnt=cnt+1 WHERE word=$new -- if (1) is a noop
**
** Update mode means:
**    (1) INSERT OR IGNORE INTO wordcount VALUES($new,0)
**    (2) UPDATE wordcount SET cnt=cnt+1 WHERE word=$new
**
** Replace mode means:
**    (1) REPLACE INTO wordcount
**        VALUES($new,ifnull((SELECT cnt FROM wordcount WHERE word=$new),0)+1);
**
** Select mode means:
**    (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
**
** Note that delete mode is 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
**
** Or:

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

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 */
  int doTrace = 0;              /* True for --trace */
  int showStats = 0;            /* True for --stats */
  int showSummary = 0;          /* True for --summary */
  int cacheSize = 0;            /* Desired cache size.  0 means default */
  int pageSize = 0;             /* Desired page size.  0 means default */
  int commitInterval = 0;       /* How often to commit.  0 means never */
  int noSync = 0;               /* True for --nosync */
  const char *zJMode = 0;       /* Journal mode */
  int nOp = 0;                  /* Operation counter */
  int i, j;                     /* Loop counters */
  sqlite3 *db;                  /* The SQLite database connection */
  char *zSql;                   /* Constructed SQL statement */
  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" */
  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,"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 ){
        showStats = 1;
      }else if( strcmp(z,"summary")==0 ){
        showSummary = 1;
      }else if( strcmp(z,"cachesize")==0 && i<argc-1 ){
        i++;
        cacheSize = atoi(argv[i]);
      }else if( strcmp(z,"pagesize")==0 && i<argc-1 ){
        i++;
        pageSize = atoi(argv[i]);
      }else if( strcmp(z,"commit")==0 && i<argc-1 ){
        i++;
        commitInterval = atoi(argv[i]);
      }else if( strcmp(z,"journal")==0 && i<argc-1 ){
        zJMode = argv[++i];
      }else{
        fatal_error("unknown option: %s\n", argv[i]);
      }
    }else if( zDbName==0 ){
      zDbName = argv[i];
    }else if( zFileToRead==0 ){
      zFileToRead = argv[i];

    if( in==0 ){
      fatal_error("Could not open input file \"%s\"\n", zFileToRead);
    }
  }else{
    in = stdin;
  }

  /* Set database connection options */
  if( doTrace ) sqlite3_trace(db, traceCallback, 0);
  if( pageSize ){
    zSql = sqlite3_mprintf("PRAGMA page_size=%d", pageSize);
    sqlite3_exec(db, zSql, 0, 0, 0);
    sqlite3_free(zSql);
  }
  if( cacheSize ){
    zSql = sqlite3_mprintf("PRAGMA cache_size=%d", cacheSize);
    sqlite3_exec(db, zSql, 0, 0, 0);
    sqlite3_free(zSql);
  }
  if( noSync ) sqlite3_exec(db, "PRAGMA synchronous=OFF", 0, 0, 0);
  if( zJMode ){
    zSql = sqlite3_mprintf("PRAGMA journal_mode=%s", zJMode);
    sqlite3_exec(db, zSql, 0, 0, 0);
    sqlite3_free(zSql);
  }


  /* Construct the "wordcount" table into which to put the words */
  if( sqlite3_exec(db, "BEGIN IMMEDIATE", 0, 0, 0) ){
    fatal_error("Could not start a transaction\n");
  }
  zSql = sqlite3_mprintf(
     "CREATE TABLE IF NOT EXISTS wordcount(\n"
     "  word TEXT PRIMARY KEY COLLATE %s,\n"
     "  cnt INTEGER\n"
     ")%s",
     useNocase ? "nocase" : "binary",
     useWithoutRowid ? " WITHOUT ROWID" : ""
  );
  if( zSql==0 ) fatal_error("out of memory\n");

    rc = sqlite3_prepare_v2(db,
          "REPLACE INTO wordcount(word,cnt)"
          "VALUES(?1,coalesce((SELECT cnt FROM wordcount WHERE word=?1),0)+1)",
          -1, &pInsert, 0);
    if( rc ) fatal_error("Could not prepare the REPLACE statement: %s\n",
                          sqlite3_errmsg(db));
  }
  if( iMode==MODE_DELETE ){
    rc = sqlite3_prepare_v2(db,
          "DELETE FROM wordcount WHERE word=?1",
          -1, &pDelete, 0);
    if( rc ) fatal_error("Could not prepare the DELETE statement: %s\n",
                         sqlite3_errmsg(db));
  }

  /* Process the input file */
  while( fgets(zInput, sizeof(zInput), in) ){
    for(i=0; zInput[i]; i++){
      if( !isalpha(zInput[i]) ) continue;
      for(j=i+1; isalpha(zInput[j]); j++){}

      /* Found a new word at zInput[i] that is j-i bytes long. 
      ** Process it into the wordcount table.  */
      if( iMode==MODE_DELETE ){
        sqlite3_bind_text(pDelete, 1, zInput+i, j-i, SQLITE_STATIC);
        if( sqlite3_step(pDelete)!=SQLITE_DONE ){
          fatal_error("DELETE failed: %s\n", sqlite3_errmsg(db));
        }
        sqlite3_reset(pDelete);
      }else if( iMode==MODE_SELECT ){
        sqlite3_bind_text(pSelect, 1, zInput+i, j-i, SQLITE_STATIC);
        rc = sqlite3_step(pSelect);
        sqlite3_reset(pSelect);
        if( rc==SQLITE_ROW ){
          sqlite3_bind_text(pUpdate, 1, zInput+i, j-i, SQLITE_STATIC);
          if( sqlite3_step(pUpdate)!=SQLITE_DONE ){
            fatal_error("UPDATE failed: %s\n", sqlite3_errmsg(db));

          if( sqlite3_step(pUpdate)!=SQLITE_DONE ){
            fatal_error("UPDATE failed: %s\n", sqlite3_errmsg(db));
          }
          sqlite3_reset(pUpdate);
        }
      }
      i = j-1;

      /* Increment the operation counter.  Do a COMMIT if it is time. */
      nOp++;
      if( commitInterval>0 && (nOp%commitInterval)==0 ){
        sqlite3_exec(db, "COMMIT; BEGIN IMMEDIATE", 0, 0, 0);
      }
    }
  }
  sqlite3_exec(db, "COMMIT", 0, 0, 0);
  if( zFileToRead ) fclose(in);
  sqlite3_finalize(pInsert);
  sqlite3_finalize(pUpdate);
  sqlite3_finalize(pSelect);
  sqlite3_finalize(pDelete);

  if( showSummary ){
    sqlite3_exec(db, 
      "SELECT '-- count(*):  ', count(*) FROM wordcount;\n"
      "SELECT '-- sum(cnt):  ', sum(cnt) FROM wordcount;\n"
      "SELECT '-- avg(cnt):  ', avg(cnt) FROM wordcount;\n"
      "SELECT '-- sum(cnt=1):', sum(cnt=1) FROM wordcount;\n"