fortune.c

CFL是Unix下的通用抽象库,以简化Unix下的系统软件开发,CFL库中包含几个分组的函数和宏

/* ----------------------------------------------------------------------------
   CFL - A C Foundation Library
   Copyright (C) 1994-2003  Mark A Lindner

   This file is part of CFL.
   
   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public
   License as published by the Free Software Foundation; either
   version 2 of the License, or (at your option) any later version.
   
   This library 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
   Library General Public License for more details.
   
   You should have received a copy of the GNU Library General Public
   License along with this library; if not, write to the Free
   Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
   ----------------------------------------------------------------------------
   $Log: fortune.c,v $
   Revision 1.2  2003/06/22 09:42:03  markl
   Fixed compatiblity probems with int??_t types.

   Revision 1.1  2003/03/03 08:20:07  markl
   Initial checkin (clean compile on Solaris & OS X)

   ----------------------------------------------------------------------------
*/

/* Feature test switches */

#include "config.h"

/* System headers */

#include <sys/types.h>
#include <netinet/in.h>
#include <string.h>

/* Local headers */

#include "cfl/defs.h"
#include "cfl/system.h"
#include "cfl/util.h"
#include "cfl/fortune.h"

/* Macros */

#define C_FORTUNE_SEPARATOR "%"
#define C_FORTUNE_INDEX_EXT "idx"

/* Functions */

c_bool_t C_fortune_indexdb(const char *basename)
  {
  char *buf, databuf[128];
  FILE *fp, *ip;
  long offset = 0;

  if(!(fp = fopen(basename, "r")))
    return(FALSE);

  buf = C_newstr(strlen(basename) + strlen(C_FORTUNE_INDEX_EXT) + 2);  
  snprintf(buf, sizeof(buf) - 1, "%s.%s", basename, C_FORTUNE_INDEX_EXT);

  if(!(ip = fopen(buf, "w+")))
    {
    fclose(fp);
    C_free(buf);
    return(FALSE);
    }

  fwrite(&offset, sizeof(offset), 1, ip);
  
  while(C_io_gets(fp, databuf, sizeof(databuf), '\n') != EOF)
    {
    if(!strcmp(databuf, C_FORTUNE_SEPARATOR))
      {
      offset = htonl(ftell(fp));
      fwrite(&offset, sizeof(offset), 1, ip);
      }
    }

  C_free(buf);

  fclose(fp);
  fclose(ip);
  return(TRUE);
  }

/*
 */

c_fortune_db_t *C_fortune_opendb(const char *basename)
  {
  c_fortune_db_t *db;
  struct stat stbuf;
  char *buf;
  size_t len;

  len = strlen(basename) + strlen(C_FORTUNE_INDEX_EXT) + 2;
  
  buf = C_newstr(len);
  snprintf(buf, len, "%s.%s", basename, C_FORTUNE_INDEX_EXT);

  if(access(basename, (F_OK | R_OK)) || access(buf, (F_OK | R_OK)))
    {
    C_free(buf);
    return(NULL);
    }

  db = C_new(c_fortune_db_t);

  db->data = fopen(basename, "r");
  db->index = fopen(buf, "r");

  stat(basename, &stbuf);
  db->filelen = stbuf.st_size;
  
  stat(buf, &stbuf);
  db->count = (stbuf.st_size / sizeof(long));

  C_free(buf);
  
  return(db);
  }

/*
 */

c_bool_t C_fortune_closedb(c_fortune_db_t *db)
  {
  if(!db)
    return(FALSE);

  fclose(db->data);
  fclose(db->index);

  C_free(db);

  return(TRUE);
  }

/*
 */

const char *C_fortune_select(c_fortune_db_t *db)
  {
  char *buf;
  int idx;
  unsigned long offset, end, fsize;
  
  if(!db)
    return(NULL);

  idx = C_random(db->count);

  fseek(db->index, (idx * sizeof(unsigned long)), SEEK_SET);
  fread(&offset, sizeof(unsigned long), 1, db->index);
  offset = ntohl(offset);

  if(idx == (db->count - 1))
    fsize = db->filelen - offset;
  else
    {
    fread(&end, sizeof(unsigned long), 1, db->index);
    fsize = ntohl(end) - offset - 2;
    }
  
  fseek(db->data, offset, SEEK_SET);

  buf = C_newb(fsize + 1);
  fread(buf, fsize, 1, db->data);

  return(buf);
  }

/* end of source file */