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| 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 _HASH_H_ | |
| 18 #define _HASH_H_ | |
| 19 | |
| 20 /* Forward declarations of structures. */ | |
| 21 typedef struct Hash Hash; | |
| 22 typedef struct HashElem HashElem; | |
| 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 Hash { | |
| 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 HashElem *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 _ht { /* the hash table */ | |
| 41 int count; /* Number of entries with this hash */ | |
| 42 HashElem *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 HashElem { | |
| 53 HashElem *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 4 different modes of operation for a hash table: | |
| 60 ** | |
| 61 ** HASH_INT nKey is used as the key and pKey is ignored. | |
| 62 ** | |
| 63 ** HASH_POINTER pKey is used as the key and nKey is ignored. | |
| 64 ** | |
| 65 ** HASH_STRING pKey points to a string that is nKey bytes long | |
| 66 ** (including the null-terminator, if any). Case | |
| 67 ** is respected in comparisons. | |
| 68 ** | |
| 69 ** HASH_BINARY pKey points to binary data nKey bytes long. | |
| 70 ** memcmp() is used to compare keys. | |
| 71 ** | |
| 72 ** A copy of the key is made for HASH_STRING and HASH_BINARY | |
| 73 ** if the copyKey parameter to HashInit is 1. | |
| 74 */ | |
| 75 /* #define HASH_INT 1 // NOT USED */ | |
| 76 /* #define HASH_POINTER 2 // NOT USED */ | |
| 77 #define HASH_STRING 3 | |
| 78 #define HASH_BINARY 4 | |
| 79 | |
| 80 /* | |
| 81 ** Access routines. To delete, insert a NULL pointer. | |
| 82 */ | |
| 83 void HashInit(Hash*, int keytype, int copyKey); | |
| 84 void *HashInsert(Hash*, const void *pKey, int nKey, void *pData); | |
| 85 void *HashFind(const Hash*, const void *pKey, int nKey); | |
| 86 void HashClear(Hash*); | |
| 87 | |
| 88 /* | |
| 89 ** Macros for looping over all elements of a hash table. The idiom is | |
| 90 ** like this: | |
| 91 ** | |
| 92 ** Hash h; | |
| 93 ** HashElem *p; | |
| 94 ** ... | |
| 95 ** for(p=HashFirst(&h); p; p=HashNext(p)){ | |
| 96 ** SomeStructure *pData = HashData(p); | |
| 97 ** // do something with pData | |
| 98 ** } | |
| 99 */ | |
| 100 #define HashFirst(H) ((H)->first) | |
| 101 #define HashNext(E) ((E)->next) | |
| 102 #define HashData(E) ((E)->data) | |
| 103 #define HashKey(E) ((E)->pKey) | |
| 104 #define HashKeysize(E) ((E)->nKey) | |
| 105 | |
| 106 /* | |
| 107 ** Number of entries in a hash table | |
| 108 */ | |
| 109 #define HashCount(H) ((H)->count) | |
| 110 | |
| 111 #endif /* _HASH_H_ */ | |
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Chromium Code Reviews
Issue 2363173002:
[sqlite] Remove obsolete reference version 3.8.7.4. (Closed)
