**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
** $Id: expr.c,v 1.44 2002/02/24 03:25:15 drh Exp $
*/
#include "sqliteInt.h"


/*
** Construct a new expression node and return a pointer to it.  Memory
** for this node is obtained from sqliteMalloc().  The calling function
................................................................................
**
** But sometimes we need an expression to persist past the time when
** the input buffer is freed.  (Example: The SELECT clause of a
** CREATE VIEW statement contains expressions that must persist for
** the life of the view.)  When that happens we have to make a
** persistent copy of the input buffer and translate the Expr.token.z
** and Expr.span.z fields to point to the copy rather than the 
** original input buffer.  The following group of routines to that
** translation.
**
** The "offset" parameter is the distance from the original input buffer
** to the persistent copy.  These routines recursively walk the entire
** expression tree and shift all tokens by "offset" amount.
**
** The work of figuring out the appropriate "offset" and making the

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
** $Id: expr.c,v 1.45 2002/02/26 23:55:31 drh Exp $
*/
#include "sqliteInt.h"


/*
** Construct a new expression node and return a pointer to it.  Memory
** for this node is obtained from sqliteMalloc().  The calling function
................................................................................
**
** But sometimes we need an expression to persist past the time when
** the input buffer is freed.  (Example: The SELECT clause of a
** CREATE VIEW statement contains expressions that must persist for
** the life of the view.)  When that happens we have to make a
** persistent copy of the input buffer and translate the Expr.token.z
** and Expr.span.z fields to point to the copy rather than the 
** original input buffer.  The following group of routines handle that
** translation.
**
** The "offset" parameter is the distance from the original input buffer
** to the persistent copy.  These routines recursively walk the entire
** expression tree and shift all tokens by "offset" amount.
**
** The work of figuring out the appropriate "offset" and making the

** This file contains the C functions that implement various SQL
** functions of SQLite.  
**
** There is only one exported symbol in this file - the function
** sqliteRegisterBuildinFunctions() found at the bottom of the file.
** All other code has file scope.
**
** $Id: func.c,v 1.2 2002/02/24 17:12:54 drh Exp $
*/
#include <ctype.h>
#include <math.h>
#include <stdlib.h>
#include "sqlite.h"

/*
................................................................................
  for(i=0; z[i]; i++){
    if( isupper(z[i]) ) z[i] = tolower(z[i]);
  }
}

/*
** An instance of the following structure holds the context of a
** standard deviation computation.
*/
typedef struct StdDevCtx StdDevCtx;
struct StdDevCtx {
  double sum;     /* Sum of terms */
  double sum2;    /* Sum of the squares of terms */
  int n;          /* Number of terms seen so far */
};
................................................................................
    sqlite_set_result_double(context, 
       sqrt((p->sum2 - p->sum*p->sum/rN)/(rN-1.0)));
  }
  if( stddev ) free(stddev);
}

/*
** This file registered all of the above C functions as SQL
** functions.

*/
void sqliteRegisterBuildinFunctions(sqlite *db){
  sqlite_create_function(db, "upper", 1, upperFunc);
  sqlite_create_function(db, "lower", 1, lowerFunc);
  sqlite_create_aggregate(db, "stddev", 1, stdDevStep, stdDevFinalize);
}

** This file contains the C functions that implement various SQL
** functions of SQLite.  
**
** There is only one exported symbol in this file - the function
** sqliteRegisterBuildinFunctions() found at the bottom of the file.
** All other code has file scope.
**
** $Id: func.c,v 1.3 2002/02/26 23:55:31 drh Exp $
*/
#include <ctype.h>
#include <math.h>
#include <stdlib.h>
#include "sqlite.h"

/*
................................................................................
  for(i=0; z[i]; i++){
    if( isupper(z[i]) ) z[i] = tolower(z[i]);
  }
}

/*
** An instance of the following structure holds the context of a
** variance or standard deviation computation.
*/
typedef struct StdDevCtx StdDevCtx;
struct StdDevCtx {
  double sum;     /* Sum of terms */
  double sum2;    /* Sum of the squares of terms */
  int n;          /* Number of terms seen so far */
};
................................................................................
    sqlite_set_result_double(context, 
       sqrt((p->sum2 - p->sum*p->sum/rN)/(rN-1.0)));
  }
  if( stddev ) free(stddev);
}

/*
** This function registered all of the above C functions as SQL
** functions.  This should be the only routine in this file with
** external linkage.
*/
void sqliteRegisterBuildinFunctions(sqlite *db){
  sqlite_create_function(db, "upper", 1, upperFunc);
  sqlite_create_function(db, "lower", 1, lowerFunc);
  sqlite_create_aggregate(db, "stddev", 1, stdDevStep, stdDevFinalize);
}