86 lines
2.8 KiB
C
86 lines
2.8 KiB
C
/*
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* This file is part of the YAP Prolog
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*
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* User Defined Indexing was developed by:
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* David Vaz <davidvaz@dcc.fc.up.pt>
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* Vitor Santos Costa <vsc@dcc.fc.up.pt>
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*
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* UDI Indexing Interface:
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*
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* Each new indexing mechanism should register it self by filling up a
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* UdiControlBlock and calling Yap_UdiRegister(UdiControlBlock).
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*
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* UdiControlBlock has the main declaration that triggers the
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* indexing structure as well as the pointers to the needed functions
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* called at the appropriate times.
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*
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* For now each indexing structure only works with a single argument
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* even when multiple arguments are indexed with the same struture.
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*
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* TODO: think of alternative ways of support both cases, e.g. a rtree
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* does not benefit from multiple rtree indexing, but a hash table do
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*/
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/* This is called upon udi mode spec call, and the purpose is to allow
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* the indexing struture to initialize itself.
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* Should return the need opaque struture to be used in future calls
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*
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* arg is used to track the specific call, on multiple indexing with the
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* same struture
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*/
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typedef void * (* Yap_UdiInit)
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(YAP_Term spec,
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int arg, /* argument regarding this call */
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int arity);
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/* Upon each assert the struture insert method is called to perform
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* its work
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*/
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typedef void * (* Yap_UdiInsert)
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(void *control, /* indexing structure opaque handle */
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YAP_Term term, /* asserted argument */
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int arg, /* argument regarding this call */
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void *data); /* value to return on search */
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/* Callback for each value found in a search
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* if it returns FALSE the search should be immediately aborted
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*/
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typedef int (* Yap_UdiCallback)
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(void *key, /* index key */
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void *data, /* data */
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void *arg); /* auxiliary data to callback */
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/* Called upon search
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*
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* If there is any search to do with this structure should return >= 0
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* corresponding to the values found
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*
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* returns -1 if there is nothing to search with this indexing structure
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* e.g. a Variable as argument
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*/
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typedef int (* Yap_UdiSearch)
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(void * control, /* indexing structure opaque handle */
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int arg, /* argument regarding this call */
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Yap_UdiCallback f, /* callback on each found value */
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void *args); /* auxiliary data to callback */
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/* Called upon abolish of the term
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* to allow for a clean destroy of the indexing structures
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*/
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typedef int (* Yap_UdiDestroy)
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(void * control);
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/*
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* Main structure used in UDI
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*/
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typedef struct udi_control_block {
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YAP_Atom decl; //atom that triggers this indexing structure
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Yap_UdiInit init;
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Yap_UdiInsert insert;
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Yap_UdiSearch search;
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Yap_UdiDestroy destroy;
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} * UdiControlBlock;
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/* Register a new indexing structure */
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void Yap_UdiRegister(UdiControlBlock);
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