bdb.c

来自「常用软件包,可以保存,做为日常函数调用,比较通用」· C语言 代码 · 共 102 行

#include "bdb.h"
#include <pthread.h>

#define min(a, b) ((a < b)? a : b)

pthread_mutex_t waitht_mutex;

////////////////////////////////////////
//////////////
//
//  Berkeley DB manupilation functions
//
////////////////////////////////////////
DB *bdbCreateOpen(char *filename) 
{
  DB *dbp;

  pthread_mutex_lock(&waitht_mutex);
  if ((dbp = dbopen(filename, O_CREAT | O_RDWR, 0666, DB_BTREE, NULL)) == NULL)
  {
	pthread_mutex_unlock(&waitht_mutex);
    return NULL;
  }
  pthread_mutex_unlock(&waitht_mutex);
  return dbp;
}

int Bdb_get(DB *dbp, char *name, int name_len, char *value, int value_len) {
  DBT db_key, db_data;
  int err;

  pthread_mutex_lock(&waitht_mutex);
  db_key.data = name;
  db_key.size = name_len;

  if ((err = dbp->get(dbp, &db_key, &db_data, 0)))
  {
	pthread_mutex_unlock(&waitht_mutex);
    return err;
  }
  else
    memcpy(value, db_data.data, min(value_len, db_data.size));

  pthread_mutex_unlock(&waitht_mutex);
  return 0;
}

int Bdb_del(DB *dbp, char *name, int name_len) 
{
  DBT db_key;
  int err;

  flock(dbp->fd(dbp),LOCK_SH);
  pthread_mutex_lock(&waitht_mutex);
  db_key.data = name;
  db_key.size = name_len;

  if ((err = dbp->del(dbp, &db_key, 0)))
  {
	pthread_mutex_unlock(&waitht_mutex);
    return err;
  }
  pthread_mutex_unlock(&waitht_mutex);
  flock(dbp->fd(dbp),LOCK_UN);

  return 0;
}


int Bdb_put(DB *dbp, char *name, int name_len, char *value, int value_len) {
  DBT db_key, db_data;
  int rtn;

  flock(dbp->fd(dbp),LOCK_SH);
  pthread_mutex_lock(&waitht_mutex);
  db_key.data = name;
  db_key.size = name_len;
  db_data.data = value;
  db_data.size = value_len;
  
  rtn = dbp->put(dbp, &db_key, &db_data, 0);
  pthread_mutex_unlock(&waitht_mutex);
  flock(dbp->fd(dbp),LOCK_UN);
  return rtn;

} 


int Bdb_close(DB *dbp) {
  int rtn;
  flock(dbp->fd(dbp),LOCK_SH);
  pthread_mutex_lock(&waitht_mutex);
  dbp->sync(dbp, 0);
  rtn = dbp->close(dbp);
  pthread_mutex_unlock(&waitht_mutex);
  flock(dbp->fd(dbp),LOCK_UN);
  return rtn;
}