xapian-applications/omega/cdb.h

   1 /* $Id: cdb.h,v 1.7 2005/04/18 09:46:50 mjt Exp $
   2  * public cdb include file
   3  *
   4  * This file is a part of tinycdb package by Michael Tokarev, mjt@corpit.ru.
   5  * Public domain.
   6  */
   7
   8 #ifndef TINYCDB_VERSION
   9 #define TINYCDB_VERSION 0.75
  10
  11 #ifdef __cplusplus
  12 // extern "C" {
  13 #endif
  14
  15 typedef unsigned int cdbi_t; /* compatibility */
  16
  17 /* common routines */
  18 unsigned cdb_hash(const void *buf, unsigned len);
  19 unsigned cdb_unpack(const unsigned char buf[4]);
  20 void cdb_pack(unsigned num, unsigned char buf[4]);
  21
  22 struct cdb {
  23   int cdb_fd;                   /* file descriptor */
  24   /* private members */
  25   unsigned cdb_fsize;           /* datafile size */
  26   unsigned cdb_dend;            /* end of data ptr */
  27   const unsigned char *cdb_mem; /* mmap'ed file memory */
  28   unsigned cdb_vpos, cdb_vlen;  /* found data */
  29   unsigned cdb_kpos, cdb_klen;  /* found key */
  30 };
  31
  32 #define CDB_STATIC_INIT {0,0,0,0,0,0,0,0}
  33
  34 #define cdb_datapos(c) ((c)->cdb_vpos)
  35 #define cdb_datalen(c) ((c)->cdb_vlen)
  36 #define cdb_keypos(c) ((c)->cdb_kpos)
  37 #define cdb_keylen(c) ((c)->cdb_klen)
  38 #define cdb_fileno(c) ((c)->cdb_fd)
  39
  40 int cdb_init(struct cdb *cdbp, int fd);
  41 void cdb_free(struct cdb *cdbp);
  42
  43 int cdb_read(const struct cdb *cdbp,
  44              void *buf, unsigned len, unsigned pos);
  45 #define cdb_readdata(cdbp, buf) \
  46         cdb_read((cdbp), (buf), cdb_datalen(cdbp), cdb_datapos(cdbp))
  47 #define cdb_readkey(cdbp, buf) \
  48         cdb_read((cdbp), (buf), cdb_keylen(cdbp), cdb_keypos(cdbp))
  49
  50 const void *cdb_get(const struct cdb *cdbp, unsigned len, unsigned pos);
  51 #define cdb_getdata(cdbp) \
  52         cdb_get((cdbp), cdb_datalen(cdbp), cdb_datapos(cdbp))
  53 #define cdb_getkey(cdbp) \
  54         cdb_get((cdbp), cdb_keylen(cdbp), cdb_keypos(cdbp))
  55
  56 int cdb_find(struct cdb *cdbp, const void *key, unsigned klen);
  57
  58 struct cdb_find {
  59   struct cdb *cdb_cdbp;
  60   unsigned cdb_hval;
  61   const unsigned char *cdb_htp, *cdb_htab, *cdb_htend;
  62   unsigned cdb_httodo;
  63   const void *cdb_key;
  64   unsigned cdb_klen;
  65 };
  66
  67 int cdb_findinit(struct cdb_find *cdbfp, struct cdb *cdbp,
  68                  const void *key, unsigned klen);
  69 int cdb_findnext(struct cdb_find *cdbfp);
  70
  71 #define cdb_seqinit(cptr, cdbp) ((*(cptr))=2048)
  72 int cdb_seqnext(unsigned *cptr, struct cdb *cdbp);
  73
  74 /* old simple interface */
  75 /* open file using standard routine, then: */
  76 int cdb_seek(int fd, const void *key, unsigned klen, unsigned *dlenp);
  77 int cdb_bread(int fd, void *buf, int len);
  78
  79 /* cdb_make */
  80
  81 struct cdb_make {
  82   int cdb_fd;                   /* file descriptor */
  83   /* private */
  84   unsigned cdb_dpos;            /* data position so far */
  85   unsigned cdb_rcnt;            /* record count so far */
  86   char cdb_buf[4096];           /* write buffer */
  87   char *cdb_bpos;               /* current buf position */
  88   struct cdb_rl *cdb_rec[256];  /* list of arrays of record infos */
  89 };
  90
  91 enum cdb_put_mode {
  92   CDB_PUT_ADD = 0,      /* add unconditionnaly, like cdb_make_add() */
  93 #define CDB_PUT_ADD     CDB_PUT_ADD
  94   CDB_FIND = CDB_PUT_ADD,
  95   CDB_PUT_REPLACE,      /* replace: do not place to index OLD record */
  96 #define CDB_PUT_REPLACE CDB_PUT_REPLACE
  97   CDB_FIND_REMOVE = CDB_PUT_REPLACE,
  98   CDB_PUT_INSERT,       /* add only if not already exists */
  99 #define CDB_PUT_INSERT  CDB_PUT_INSERT
 100   CDB_PUT_WARN,         /* add unconditionally but ret. 1 if exists */
 101 #define CDB_PUT_WARN    CDB_PUT_WARN
 102   CDB_PUT_REPLACE0,     /* if a record exists, fill old one with zeros */
 103 #define CDB_PUT_REPLACE0 CDB_PUT_REPLACE0
 104   CDB_FIND_FILL0 = CDB_PUT_REPLACE0
 105 };
 106
 107 int cdb_make_start(struct cdb_make *cdbmp, int fd);
 108 int cdb_make_add(struct cdb_make *cdbmp,
 109                  const void *key, unsigned klen,
 110                  const void *val, unsigned vlen);
 111 int cdb_make_exists(struct cdb_make *cdbmp,
 112                     const void *key, unsigned klen);
 113 int cdb_make_find(struct cdb_make *cdbmp,
 114                   const void *key, unsigned klen,
 115                   enum cdb_put_mode mode);
 116 int cdb_make_put(struct cdb_make *cdbmp,
 117                  const void *key, unsigned klen,
 118                  const void *val, unsigned vlen,
 119                  enum cdb_put_mode mode);
 120 int cdb_make_finish(struct cdb_make *cdbmp);
 121
 122 #ifdef __cplusplus
 123 // } /* extern "C" */
 124 #endif
 125
 126 #endif /* include guard */