src/test_intarray.h

   1 /*
   2 ** 2009 November 10
   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 **
  13 ** This is the C-language interface definition for the "intarray" or
  14 ** integer array virtual table for SQLite.
  15 **
  16 ** The intarray virtual table is designed to facilitate using an
  17 ** array of integers as the right-hand side of an IN operator.  So
  18 ** instead of doing a prepared statement like this:
  19 **
  20 **     SELECT * FROM table WHERE x IN (?,?,?,...,?);
  21 **
  22 ** And then binding indivdual integers to each of ? slots, a C-language
  23 ** application can create an intarray object (named "ex1" in the following
  24 ** example), prepare a statement like this:
  25 **
  26 **     SELECT * FROM table WHERE x IN ex1;
  27 **
  28 ** Then bind an ordinary C/C++ array of integer values to the ex1 object
  29 ** to run the statement.
  30 **
  31 ** USAGE:
  32 **
  33 ** One or more intarray objects can be created as follows:
  34 **
  35 **      sqlite3_intarray *p1, *p2, *p3;
  36 **      sqlite3_intarray_create(db, "ex1", &p1);
  37 **      sqlite3_intarray_create(db, "ex2", &p2);
  38 **      sqlite3_intarray_create(db, "ex3", &p3);
  39 **
  40 ** Each call to sqlite3_intarray_create() generates a new virtual table
  41 ** module and a singleton of that virtual table module in the TEMP
  42 ** database.  Both the module and the virtual table instance use the
  43 ** name given by the second parameter.  The virtual tables can then be
  44 ** used in prepared statements:
  45 **
  46 **      SELECT * FROM t1, t2, t3
  47 **       WHERE t1.x IN ex1
  48 **         AND t2.y IN ex2
  49 **         AND t3.z IN ex3;
  50 **
  51 ** Each integer array is initially empty.  New arrays can be bound to
  52 ** an integer array as follows:
  53 **
  54 **     sqlite3_int64 a1[] = { 1, 2, 3, 4 };
  55 **     sqlite3_int64 a2[] = { 5, 6, 7, 8, 9, 10, 11 };
  56 **     sqlite3_int64 *a3 = sqlite3_malloc( 100*sizeof(sqlite3_int64) );
  57 **     // Fill in content of a3[]
  58 **     sqlite3_intarray_bind(p1, 4, a1, 0);
  59 **     sqlite3_intarray_bind(p2, 7, a2, 0);
  60 **     sqlite3_intarray_bind(p3, 100, a3, sqlite3_free);
  61 **
  62 ** A single intarray object can be rebound multiple times.  But do not
  63 ** attempt to change the bindings of an intarray while it is in the middle
  64 ** of a query.
  65 **
  66 ** The array that holds the integers is automatically freed by the function
  67 ** in the fourth parameter to sqlite3_intarray_bind() when the array is no
  68 ** longer needed.  The application must not change the intarray values
  69 ** while an intarray is in the middle of a query.
  70 **
  71 ** The intarray object is automatically destroyed when its corresponding
  72 ** virtual table is dropped.  Since the virtual tables are created in the
  73 ** TEMP database, they are automatically dropped when the database connection
  74 ** closes so the application does not normally need to take any special
  75 ** action to free the intarray objects.
  76 */
  77 #include "sqlite3.h"
  78
  79 /*
  80 ** An sqlite3_intarray is an abstract type to stores an instance of
  81 ** an integer array.
  82 */
  83 typedef struct sqlite3_intarray sqlite3_intarray;
  84
  85 /*
  86 ** Invoke this routine to create a specific instance of an intarray object.
  87 ** The new intarray object is returned by the 3rd parameter.
  88 **
  89 ** Each intarray object corresponds to a virtual table in the TEMP table
  90 ** with a name of zName.
  91 **
  92 ** Destroy the intarray object by dropping the virtual table.  If not done
  93 ** explicitly by the application, the virtual table will be dropped implicitly
  94 ** by the system when the database connection is closed.
  95 */
  96 int sqlite3_intarray_create(
  97   sqlite3 *db,
  98   const char *zName,
  99   sqlite3_intarray **ppReturn
 100 );
 101
 102 /*
 103 ** Bind a new array array of integers to a specific intarray object.
 104 **
 105 ** The array of integers bound must be unchanged for the duration of
 106 ** any query against the corresponding virtual table.  If the integer
 107 ** array does change or is deallocated undefined behavior will result.
 108 */
 109 int sqlite3_intarray_bind(
 110   sqlite3_intarray *pIntArray,   /* The intarray object to bind to */
 111   int nElements,                 /* Number of elements in the intarray */
 112   sqlite3_int64 *aElements,      /* Content of the intarray */
 113   void (*xFree)(void*)           /* How to dispose of the intarray when done */
 114 );