db5.c

Go to the documentation of this file.

#include <stdio.h>
#include <string.h>
#include <ham/hamsterdb.h>

#define DATABASE_NAME     1

int
main(int argc, char **argv) {
  ham_status_t st;          /* status variable */
  ham_env_t *env;           /* hamsterdb environment object */
  ham_db_t *db;             /* hamsterdb database object */
  ham_cursor_t *cursor;     /* a database cursor */
  char line[1024 * 4];      /* a buffer for reading lines */
  unsigned lineno = 0;      /* the current line number */
  ham_key_t key;
  ham_record_t record;

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

  printf("This sample uses hamsterdb and duplicate keys to list all words "
      "in the\noriginal order, together with their line number.\n");
  printf("Reading from stdin...\n");

  /* Create a new Database with support for duplicate keys */
  st = ham_env_create(&env, 0, HAM_IN_MEMORY, 0664, 0);
  if (st != HAM_SUCCESS) {
    printf("ham_env_create() failed with error %d\n", st);
    return (-1);
  }
  st = ham_env_create_db(env, &db, DATABASE_NAME,
          HAM_ENABLE_EXTENDED_KEYS | HAM_ENABLE_DUPLICATES, 0);
  if (st != HAM_SUCCESS) {
    printf("ham_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;
    lineno++;

    /*
     * 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"))) {
      key.data = p;
      key.size = (ham_size_t)strlen(p) + 1; /* also store the terminating
                                             * 0-byte */
      record.data = &lineno;
      record.size = sizeof(lineno);

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

      start = 0;
    }
  }

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

  /* Iterate over all items and print them */
  while (1) {
    st = ham_cursor_move(cursor, &key, &record, HAM_CURSOR_NEXT);
    if (st != HAM_SUCCESS) {
      /* reached end of the database? */
      if (st == HAM_KEY_NOT_FOUND)
        break;
      else {
        printf("ham_cursor_next() failed with error %d\n", st);
        return (-1);
      }
    }

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

  /*
   * Then close the handles; the flag HAM_AUTO_CLEANUP will automatically
   * close all cursors and we do not need to call ham_cursor_close and
   * ham_db_close
   */
  st = ham_env_close(env, HAM_AUTO_CLEANUP);
  if (st != HAM_SUCCESS) {
    printf("ham_env_close() failed with error %d\n", st);
    return (-1);
  }

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