modernc.org/cc@v1.0.1/v2/testdata/_sqlite/ext/fts1/fts1_hash.h (about)

     1  /*
     2  ** 2001 September 22
     3  **
     4  ** The author disclaims copyright to this source code.  In place of
     5  ** a legal notice, here is a blessing:
     6  **
     7  **    May you do good and not evil.
     8  **    May you find forgiveness for yourself and forgive others.
     9  **    May you share freely, never taking more than you give.
    10  **
    11  *************************************************************************
    12  ** This is the header file for the generic hash-table implementation
    13  ** used in SQLite.  We've modified it slightly to serve as a standalone
    14  ** hash table implementation for the full-text indexing module.
    15  **
    16  */
    17  #ifndef _FTS1_HASH_H_
    18  #define _FTS1_HASH_H_
    19  
    20  /* Forward declarations of structures. */
    21  typedef struct fts1Hash fts1Hash;
    22  typedef struct fts1HashElem fts1HashElem;
    23  
    24  /* A complete hash table is an instance of the following structure.
    25  ** The internals of this structure are intended to be opaque -- client
    26  ** code should not attempt to access or modify the fields of this structure
    27  ** directly.  Change this structure only by using the routines below.
    28  ** However, many of the "procedures" and "functions" for modifying and
    29  ** accessing this structure are really macros, so we can't really make
    30  ** this structure opaque.
    31  */
    32  struct fts1Hash {
    33    char keyClass;          /* HASH_INT, _POINTER, _STRING, _BINARY */
    34    char copyKey;           /* True if copy of key made on insert */
    35    int count;              /* Number of entries in this table */
    36    fts1HashElem *first;    /* The first element of the array */
    37    void *(*xMalloc)(int);  /* malloc() function to use */
    38    void (*xFree)(void *);  /* free() function to use */
    39    int htsize;             /* Number of buckets in the hash table */
    40    struct _fts1ht {        /* the hash table */
    41      int count;               /* Number of entries with this hash */
    42      fts1HashElem *chain;     /* Pointer to first entry with this hash */
    43    } *ht;
    44  };
    45  
    46  /* Each element in the hash table is an instance of the following 
    47  ** structure.  All elements are stored on a single doubly-linked list.
    48  **
    49  ** Again, this structure is intended to be opaque, but it can't really
    50  ** be opaque because it is used by macros.
    51  */
    52  struct fts1HashElem {
    53    fts1HashElem *next, *prev; /* Next and previous elements in the table */
    54    void *data;                /* Data associated with this element */
    55    void *pKey; int nKey;      /* Key associated with this element */
    56  };
    57  
    58  /*
    59  ** There are 2 different modes of operation for a hash table:
    60  **
    61  **   FTS1_HASH_STRING        pKey points to a string that is nKey bytes long
    62  **                           (including the null-terminator, if any).  Case
    63  **                           is respected in comparisons.
    64  **
    65  **   FTS1_HASH_BINARY        pKey points to binary data nKey bytes long. 
    66  **                           memcmp() is used to compare keys.
    67  **
    68  ** A copy of the key is made if the copyKey parameter to fts1HashInit is 1.  
    69  */
    70  #define FTS1_HASH_STRING    1
    71  #define FTS1_HASH_BINARY    2
    72  
    73  /*
    74  ** Access routines.  To delete, insert a NULL pointer.
    75  */
    76  void sqlite3Fts1HashInit(fts1Hash*, int keytype, int copyKey);
    77  void *sqlite3Fts1HashInsert(fts1Hash*, const void *pKey, int nKey, void *pData);
    78  void *sqlite3Fts1HashFind(const fts1Hash*, const void *pKey, int nKey);
    79  void sqlite3Fts1HashClear(fts1Hash*);
    80  
    81  /*
    82  ** Shorthand for the functions above
    83  */
    84  #define fts1HashInit   sqlite3Fts1HashInit
    85  #define fts1HashInsert sqlite3Fts1HashInsert
    86  #define fts1HashFind   sqlite3Fts1HashFind
    87  #define fts1HashClear  sqlite3Fts1HashClear
    88  
    89  /*
    90  ** Macros for looping over all elements of a hash table.  The idiom is
    91  ** like this:
    92  **
    93  **   fts1Hash h;
    94  **   fts1HashElem *p;
    95  **   ...
    96  **   for(p=fts1HashFirst(&h); p; p=fts1HashNext(p)){
    97  **     SomeStructure *pData = fts1HashData(p);
    98  **     // do something with pData
    99  **   }
   100  */
   101  #define fts1HashFirst(H)  ((H)->first)
   102  #define fts1HashNext(E)   ((E)->next)
   103  #define fts1HashData(E)   ((E)->data)
   104  #define fts1HashKey(E)    ((E)->pKey)
   105  #define fts1HashKeysize(E) ((E)->nKey)
   106  
   107  /*
   108  ** Number of entries in a hash table
   109  */
   110  #define fts1HashCount(H)  ((H)->count)
   111  
   112  #endif /* _FTS1_HASH_H_ */