db4.c

/*
 * Copyright (C) 2005-2015 Christoph Rupp (chris@crupp.de).
 * All Rights Reserved.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * See the file COPYING for License information.
 */

/**
 * This sample uses hamsterdb to read data from stdin into a "record number"
 * database; every word is inserted into the database in the order of
 * its processing. Then a cursor is used to print all words in the
 * original order.
 */

#include <stdio.h>
#include <string.h>
#include <ups/upscaledb.h>

#define DATABASE_NAME       1

int
main(int argc, char **argv) {
  ups_status_t st;    /* status variable */
  ups_env_t *env;     /* hamsterdb environment object */
  ups_db_t *db;       /* hamsterdb database object */
  ups_cursor_t *cursor;   /* a database cursor */
  char line[1024 * 4];  /* a buffer for reading lines */
  ups_key_t key;
  ups_record_t record;

  memset(&key, 0, sizeof(key));
  memset(&record, 0, sizeof(record));

  printf("This sample uses hamsterdb to list all words in the "
      "original order.\n");
  printf("Reading from stdin...\n");

  /*
   * Create a new hamsterdb "record number" Database.
   * We could create an in-memory-Environment to speed up the sorting.
   */
  st = ups_env_create(&env, "test.db", 0, 0664, 0);
  if (st != UPS_SUCCESS) {
    printf("ups_env_create() failed with error %d\n", st);
    return (-1);
  }

  st = ups_env_create_db(env, &db, DATABASE_NAME, UPS_RECORD_NUMBER32, 0);
  if (st != UPS_SUCCESS) {
    printf("ups_env_create_db() failed with error %d\n", st);
    return (-1);
  }

  /*
   * Now read each line from stdin and split it in words; then each
   * word is inserted into the database
   */
  while (fgets(line, sizeof(line), stdin)) {
    char *start = line, *p;

    /*
     * strtok is not the best function because it's not threadsafe
     * and not flexible, but it's good enough for this example.
     */
    while ((p = strtok(start, " \t\r\n"))) {
      uint32_t recno;

      key.flags = UPS_KEY_USER_ALLOC;
      key.data = &recno;
      key.size = sizeof(recno);

      record.data = p;
      record.size = (uint32_t)strlen(p) + 1; /* also store
                            * terminating 0 */

      st = ups_db_insert(db, 0, &key, &record, 0);
      if (st != UPS_SUCCESS && st != UPS_DUPLICATE_KEY) {
        printf("ups_db_insert() failed with error %d\n", st);
        return (-1);
      }
      printf(".");

      start = 0;
    }
  }

  /* Create a cursor */
  st = ups_cursor_create(&cursor, db, 0, 0);
  if (st != UPS_SUCCESS) {
    printf("ups_cursor_create() failed with error %d\n", st);
    return (-1);
  }

  memset(&key, 0, sizeof(key));

  /* Iterate over all items and print the records */
  while (1) {
    st = ups_cursor_move(cursor, &key, &record, UPS_CURSOR_NEXT);
    if (st != UPS_SUCCESS) {
      /* reached end of the database? */
      if (st == UPS_KEY_NOT_FOUND)
        break;
      else {
        printf("ups_cursor_next() failed with error %d\n", st);
        return (-1);
      }
    }

    /* print the record number and the word */
    printf("%u: %s\n", *(uint32_t *)key.data, (const char *)record.data);
  }

  /*
   * Then close the handles; the flag UPS_AUTO_CLEANUP will automatically 
   * close all databases and cursors and we do not need to
   * call ups_cursor_close and ups_db_close
   */
  st = ups_env_close(env, UPS_AUTO_CLEANUP);
  if (st != UPS_SUCCESS) {
    printf("ups_env_close() failed with error %d\n", st);
    return (-1);
  }

  /* success! */
  return (0);
}