ext/misc/noop.c

   1 /*
   2 ** 2020-01-08
   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 SQLite extension implements a noop() function used for testing.
  14 **
  15 ** Variants:
  16 **
  17 **    noop(X)           The default.  Deterministic.
  18 **    noop_i(X)         Deterministic and innocuous.
  19 **    noop_do(X)        Deterministic and direct-only.
  20 **    noop_nd(X)        Non-deterministic.
  21 */
  22 #include "sqlite3ext.h"
  23 SQLITE_EXTENSION_INIT1
  24 #include <assert.h>
  25 #include <string.h>
  26
  27 /*
  28 ** Implementation of the noop() function.
  29 **
  30 ** The function returns its argument, unchanged.
  31 */
  32 static void noopfunc(
  33   sqlite3_context *context,
  34   int argc,
  35   sqlite3_value **argv
  36 ){
  37   assert( argc==1 );
  38   sqlite3_result_value(context, argv[0]);
  39 }
  40
  41 /*
  42 ** Implementation of the multitype_text() function.
  43 **
  44 ** The function returns its argument.  The result will always have a
  45 ** TEXT value.  But if the original input is numeric, it will also
  46 ** have that numeric value.
  47 */
  48 static void multitypeTextFunc(
  49   sqlite3_context *context,
  50   int argc,
  51   sqlite3_value **argv
  52 ){
  53   assert( argc==1 );
  54   (void)argc;
  55   (void)sqlite3_value_text(argv[0]);
  56   sqlite3_result_value(context, argv[0]);
  57 }
  58
  59 #ifdef _WIN32
  60 __declspec(dllexport)
  61 #endif
  62 int sqlite3_noop_init(
  63   sqlite3 *db,
  64   char **pzErrMsg,
  65   const sqlite3_api_routines *pApi
  66 ){
  67   int rc = SQLITE_OK;
  68   SQLITE_EXTENSION_INIT2(pApi);
  69   (void)pzErrMsg;  /* Unused parameter */
  70   rc = sqlite3_create_function(db, "noop", 1,
  71                      SQLITE_UTF8 | SQLITE_DETERMINISTIC,
  72                      0, noopfunc, 0, 0);
  73   if( rc ) return rc;
  74   rc = sqlite3_create_function(db, "noop_i", 1,
  75                      SQLITE_UTF8 | SQLITE_DETERMINISTIC | SQLITE_INNOCUOUS,
  76                      0, noopfunc, 0, 0);
  77   if( rc ) return rc;
  78   rc = sqlite3_create_function(db, "noop_do", 1,
  79                      SQLITE_UTF8 | SQLITE_DETERMINISTIC | SQLITE_DIRECTONLY,
  80                      0, noopfunc, 0, 0);
  81   if( rc ) return rc;
  82   rc = sqlite3_create_function(db, "noop_nd", 1,
  83                      SQLITE_UTF8,
  84                      0, noopfunc, 0, 0);
  85   if( rc ) return rc;
  86   rc = sqlite3_create_function(db, "multitype_text", 1,
  87                      SQLITE_UTF8,
  88                      0, multitypeTextFunc, 0, 0);
  89   return rc;
  90 }