/*
** 2002 February 23
**
** The author disclaims copyright to this source code. In place of
** a legal notice, here is a blessing:
**
** May you do good and not evil.
** May you find forgiveness for yourself and forgive others.
** May you share freely, never taking more than you give.
**
*************************************************************************
** 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 1.57 2004/05/26 16:54:43 drh Exp $
*/
#include <ctype.h>
#include <math.h>
#include <stdlib.h>
#include <assert.h>
#include "sqliteInt.h"
#include "vdbeInt.h"
#include "os.h"
/*
** Implementation of the non-aggregate min() and max() functions
*/
static void minmaxFunc(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
int i;
int mask; /* 0 for min() or 0xffffffff for max() */
int iBest;
if( argc==0 ) return;
mask = (int)sqlite3_user_data(context);
iBest = 0;
for(i=1; i<argc; i++){
if( (sqlite3MemCompare(argv[iBest], argv[i], 0)^mask)<0 ){
iBest = i;
}
}
sqlite3_result(context, argv[iBest]);
}
/*
** Return the type of the argument.
*/
static void typeofFunc(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
const char *z = 0;
switch( sqlite3_value_type(argv[0]) ){
case SQLITE3_NULL: z = "null"; break;
case SQLITE3_INTEGER: z = "integer"; break;
case SQLITE3_TEXT: z = "text"; break;
case SQLITE3_FLOAT: z = "real"; break;
case SQLITE3_BLOB: z = "blob"; break;
}
sqlite3_result_text(context, z, -1, 0);
}
/*
** Implementation of the length() function
*/
static void lengthFunc(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
const char *z;
int len;
assert( argc==1 );
switch( sqlite3_value_type(argv[0]) ){
case SQLITE3_BLOB:
case SQLITE3_INTEGER:
case SQLITE3_FLOAT: {
sqlite3_result_int32(context, sqlite3_value_bytes(argv[0]));
break;
}
case SQLITE3_TEXT: {
const char *z = sqlite3_value_data(argv[0]);
for(len=0; *z; z++){ if( (0xc0&*z)!=0x80 ) len++; }
sqlite3_result_int32(context, len);
break;
}
default: {
sqlite3_result_null(context);
break;
}
}
}
/*
** Implementation of the abs() function
*/
static void absFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
const char *z;
assert( argc==1 );
switch( sqlite3_value_type(argv[0]) ){
case SQLITE3_INTEGER: {
sqlite3_result_int64(context, -sqlite3_value_int(argv[0]));
break;
}
case SQLITE3_NULL: {
sqlite3_result_null(context);
break;
}
default: {
sqlite3_result_double(context, -sqlite3_value_float(argv[0]));
break;
}
}
}
/*
** Implementation of the substr() function
*/
static void substrFunc(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
const char *z;
const char *z2;
int i;
int p1, p2, len;
assert( argc==3 );
z = sqlite3_value_data(argv[0]);
if( z==0 ) return;
p1 = sqlite3_value_int(argv[1]);
p2 = sqlite3_value_int(argv[2]);
for(len=0, z2=z; *z2; z2++){ if( (0xc0&*z2)!=0x80 ) len++; }
if( p1<0 ){
p1 += len;
if( p1<0 ){
p2 += p1;
p1 = 0;
}
}else if( p1>0 ){
p1--;
}
if( p1+p2>len ){
p2 = len-p1;
}
for(i=0; i<p1 && z[i]; i++){
if( (z[i]&0xc0)==0x80 ) p1++;
}
while( z[i] && (z[i]&0xc0)==0x80 ){ i++; p1++; }
for(; i<p1+p2 && z[i]; i++){
if( (z[i]&0xc0)==0x80 ) p2++;
}
while( z[i] && (z[i]&0xc0)==0x80 ){ i++; p2++; }
if( p2<0 ) p2 = 0;
sqlite3_result_text(context, &z[p1], p2, 1);
}
/*
** Implementation of the round() function
*/
static void roundFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
int n = 0;
double r;
char zBuf[100];
assert( argc==1 || argc==2 );
if( argc==2 ){
if( SQLITE3_NULL==sqlite3_value_type(argv[1]) ) return;
n = sqlite3_value_int(argv[1]);
if( n>30 ) n = 30;
if( n<0 ) n = 0;
}
if( SQLITE3_NULL==sqlite3_value_type(argv[0]) ) return;
r = sqlite3_value_float(argv[0]);
sprintf(zBuf,"%.*f",n,r);
sqlite3_result_text(context, zBuf, -1, 1);
}
/*
** Implementation of the upper() and lower() SQL functions.
*/
static void upperFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
char *z;
int i;
if( argc<1 || SQLITE3_NULL==sqlite3_value_type(argv[0]) ) return;
z = sqliteMalloc(sqlite3_value_bytes(argv[0]));
if( z==0 ) return;
strcpy(z, sqlite3_value_data(argv[0]));
for(i=0; z[i]; i++){
if( islower(z[i]) ) z[i] = toupper(z[i]);
}
sqlite3_result_text(context, z, -1, 1);
sqliteFree(z);
}
static void lowerFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
char *z;
int i;
if( argc<1 || SQLITE3_NULL==sqlite3_value_type(argv[0]) ) return;
z = sqliteMalloc(sqlite3_value_bytes(argv[0]));
if( z==0 ) return;
strcpy(z, sqlite3_value_data(argv[0]));
for(i=0; z[i]; i++){
if( isupper(z[i]) ) z[i] = tolower(z[i]);
}
sqlite3_result_text(context, z, -1, 1);
sqliteFree(z);
}
/*
** Implementation of the IFNULL(), NVL(), and COALESCE() functions.
** All three do the same thing. They return the first non-NULL
** argument.
*/
static void ifnullFunc(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
int i;
for(i=0; i<argc; i++){
if( SQLITE3_NULL!=sqlite3_value_type(argv[i]) ){
sqlite3_result(context, argv[i]);
break;
}
}
}
/*
** Implementation of random(). Return a random integer.
*/
static void randomFunc(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
int r;
sqlite3Randomness(sizeof(r), &r);
sqlite3_result_int32(context, r);
}
/*
** Implementation of the last_insert_rowid() SQL function. The return
** value is the same as the sqlite3_last_insert_rowid() API function.
*/
static void last_insert_rowid(
sqlite3_context *context,
int arg,
sqlite3_value **argv
){
sqlite *db = sqlite3_user_data(context);
sqlite3_result_int64(context, sqlite3_last_insert_rowid(db));
}
/*
** Implementation of the change_count() SQL function. The return
** value is the same as the sqlite3_changes() API function.
*/
static void change_count(
sqlite3_context *context,
int arg,
sqlite3_value **argv
){
sqlite *db = sqlite3_user_data(context);
sqlite3_result_int32(context, sqlite3_changes(db));
}
/*
** Implementation of the last_statement_change_count() SQL function. The
** return value is the same as the sqlite3_last_statement_changes() API
** function.
*/
static void last_statement_change_count(
sqlite3_context *context,
int arg,
sqlite3_value **argv
){
sqlite *db = sqlite3_user_data(context);
sqlite3_result_int32(context, sqlite3_last_statement_changes(db));
}
/*
** Implementation of the like() SQL function. This function implements
** the build-in LIKE operator. The first argument to the function is the
** string and the second argument is the pattern. So, the SQL statements:
**
** A LIKE B
**
** is implemented as like(A,B).
*/
static void likeFunc(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
const unsigned char *zA = sqlite3_value_data(argv[0]);
const unsigned char *zB = sqlite3_value_data(argv[1]);
if( zA && zB ){
sqlite3_result_int32(context, sqlite3LikeCompare(zA, zB));
}
}
/*
** Implementation of the glob() SQL function. This function implements
** the build-in GLOB operator. The first argument to the function is the
** string and the second argument is the pattern. So, the SQL statements:
**
** A GLOB B
**
** is implemented as glob(A,B).
*/
static void globFunc(sqlite3_context *context, int arg, sqlite3_value **argv){
const unsigned char *zA = sqlite3_value_data(argv[0]);
const unsigned char *zB = sqlite3_value_data(argv[1]);
if( zA && zB ){
sqlite3_result_int32(context, sqlite3GlobCompare(zA, zB));
}
}
/*
** Implementation of the NULLIF(x,y) function. The result is the first
** argument if the arguments are different. The result is NULL if the
** arguments are equal to each other.
*/
static void nullifFunc(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
if( sqlite3MemCompare(argv[0], argv[1], 0)!=0 ){
sqlite3_result(context, argv[0]);
}
}
/*
** Implementation of the VERSION(*) function. The result is the version
** of the SQLite library that is running.
*/
static void versionFunc(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
sqlite3_result_text(context, sqlite3_version, -1, 0);
}
/*
** EXPERIMENTAL - This is not an official function. The interface may
** change. This function may disappear. Do not write code that depends
** on this function.
**
** Implementation of the QUOTE() function. This function takes a single
** argument. If the argument is numeric, the return value is the same as
** the argument. If the argument is NULL, the return value is the string
** "NULL". Otherwise, the argument is enclosed in single quotes with
** single-quote escapes.
*/
static void quoteFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
const char *zArg = sqlite3_value_data(argv[0]);
if( argc<1 ) return;
switch( sqlite3_value_type(argv[0]) ){
case SQLITE3_NULL: {
sqlite3_result_text(context, "NULL", 4, 0);
break;
}
case SQLITE3_INTEGER:
case SQLITE3_FLOAT: {
sqlite3_result(context, argv[0]);
break;
}
case SQLITE3_BLOB: /*** FIX ME. Use a BLOB encoding ***/
case SQLITE3_TEXT: {
int i,j,n;
const char *zArg = sqlite3_value_data(argv[0]);
char *z;
for(i=n=0; zArg[i]; i++){ if( zArg[i]=='\'' ) n++; }
z = sqliteMalloc( i+n+3 );
if( z==0 ) return;
z[0] = '\'';
for(i=0, j=1; zArg[i]; i++){
z[j++] = zArg[i];
if( zArg[i]=='\'' ){
z[j++] = '\'';
}
}
z[j++] = '\'';
z[j] = 0;
sqlite3_result_text(context, z, j, 1);
sqliteFree(z);
}
}
}
#ifdef SQLITE_SOUNDEX
/*
** Compute the soundex encoding of a word.
*/
static void soundexFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
char zResult[8];
const char *zIn;
int i, j;
static const unsigned char iCode[] = {
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 1, 2, 3, 0, 1, 2, 0, 0, 2, 2, 4, 5, 5, 0,
1, 2, 6, 2, 3, 0, 1, 0, 2, 0, 2, 0, 0, 0, 0, 0,
0, 0, 1, 2, 3, 0, 1, 2, 0, 0, 2, 2, 4, 5, 5, 0,
1, 2, 6, 2, 3, 0, 1, 0, 2, 0, 2, 0, 0, 0, 0, 0,
};
assert( argc==1 );
zIn = sqlite3_value_data(argv[0]);
for(i=0; zIn[i] && !isalpha(zIn[i]); i++){}
if( zIn[i] ){
zResult[0] = toupper(zIn[i]);
for(j=1; j<4 && zIn[i]; i++){
int code = iCode[zIn[i]&0x7f];
if( code>0 ){
zResult[j++] = code + '0';
}
}
while( j<4 ){
zResult[j++] = '0';
}
zResult[j] = 0;
sqlite3_result_text(context, zResult, 4, 1);
}else{
sqlite3_result_text(context, "?000", 4, 0);
}
}
#endif
#ifdef SQLITE_TEST
/*
** This function generates a string of random characters. Used for
** generating test data.
*/
static void randStr(sqlite3_context *context, int argc, sqlite3_value **argv){
static const unsigned char zSrc[] =
"abcdefghijklmnopqrstuvwxyz"
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"0123456789"
".-!,:*^+=_|?/<> ";
int iMin, iMax, n, r, i;
unsigned char zBuf[1000];
if( argc>=1 ){
iMin = sqlite3_value_int(argv[0]);
if( iMin<0 ) iMin = 0;
if( iMin>=sizeof(zBuf) ) iMin = sizeof(zBuf)-1;
}else{
iMin = 1;
}
if( argc>=2 ){
iMax = sqlite3_value_int(argv[1]);
if( iMax<iMin ) iMax = iMin;
if( iMax>=sizeof(zBuf) ) iMax = sizeof(zBuf)-1;
}else{
iMax = 50;
}
n = iMin;
if( iMax>iMin ){
sqlite3Randomness(sizeof(r), &r);
r &= 0x7fffffff;
n += r%(iMax + 1 - iMin);
}
assert( n<sizeof(zBuf) );
sqlite3Randomness(n, zBuf);
for(i=0; i<n; i++){
zBuf[i] = zSrc[zBuf[i]%(sizeof(zSrc)-1)];
}
zBuf[n] = 0;
sqlite3_result_text(context, zBuf, n, 1);
}
#endif
/*
** An instance of the following structure holds the context of a
** sum() or avg() aggregate computation.
*/
typedef struct SumCtx SumCtx;
struct SumCtx {
double sum; /* Sum of terms */
int cnt; /* Number of elements summed */
};
/*
** Routines used to compute the sum or average.
*/
static void sumStep(sqlite3_context *context, int argc, sqlite3_value **argv){
SumCtx *p;
if( argc<1 ) return;
p = sqlite3_get_context(context, sizeof(*p));
if( p && SQLITE3_NULL!=sqlite3_value_type(argv[0]) ){
p->sum += sqlite3_value_float(argv[0]);
p->cnt++;
}
}
static void sumFinalize(sqlite3_context *context){
SumCtx *p;
p = sqlite3_get_context(context, sizeof(*p));
sqlite3_result_double(context, p ? p->sum : 0.0);
}
static void avgFinalize(sqlite3_context *context){
SumCtx *p;
p = sqlite3_get_context(context, sizeof(*p));
if( p && p->cnt>0 ){
sqlite3_result_double(context, p->sum/(double)p->cnt);
}
}
/*
** 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 cnt; /* Number of terms counted */
};
#if 0 /* Omit because math library is required */
/*
** Routines used to compute the standard deviation as an aggregate.
*/
static void stdDevStep(sqlite3_context *context, int argc, const char **argv){
StdDevCtx *p;
double x;
if( argc<1 ) return;
p = sqlite3_aggregate_context(context, sizeof(*p));
if( p && argv[0] ){
x = sqlite3AtoF(argv[0], 0);
p->sum += x;
p->sum2 += x*x;
p->cnt++;
}
}
static void stdDevFinalize(sqlite3_context *context){
double rN = sqlite3_aggregate_count(context);
StdDevCtx *p = sqlite3_aggregate_context(context, sizeof(*p));
if( p && p->cnt>1 ){
double rCnt = cnt;
sqlite3_set_result_double(context,
sqrt((p->sum2 - p->sum*p->sum/rCnt)/(rCnt-1.0)));
}
}
#endif
/*
** The following structure keeps track of state information for the
** count() aggregate function.
*/
typedef struct CountCtx CountCtx;
struct CountCtx {
int n;
};
/*
** Routines to implement the count() aggregate function.
*/
static void countStep(sqlite3_context *context, int argc, sqlite3_value **argv){
CountCtx *p;
p = sqlite3_get_context(context, sizeof(*p));
if( (argc==0 || SQLITE3_NULL!=sqlite3_value_type(argv[0])) && p ){
p->n++;
}
}
static void countFinalize(sqlite3_context *context){
CountCtx *p;
p = sqlite3_get_context(context, sizeof(*p));
sqlite3_result_int32(context, p ? p->n : 0);
}
/*
** This function tracks state information for the min() and max()
** aggregate functions.
*/
typedef struct MinMaxCtx MinMaxCtx;
struct MinMaxCtx {
char *z; /* The best so far */
char zBuf[28]; /* Space that can be used for storage */
};
/*
** Routines to implement min() and max() aggregate functions.
*/
static void minmaxStep(sqlite3_context *context, int argc, sqlite3_value **argv){
int max = 0;
int cmp = 0;
Mem *pArg = (Mem *)argv[0];
Mem *pBest = (Mem *)sqlite3_get_context(context, sizeof(*pBest));
if( SQLITE3_NULL==sqlite3_value_type(argv[0]) ) return;
if( pBest->flags ){
/* This step function is used for both the min() and max() aggregates,
** the only difference between the two being that the sense of the
** comparison is inverted. For the max() aggregate, the
** sqlite3_user_data() function returns (void *)-1. For min() it
** returns (void *)db, where db is the sqlite3* database pointer.
** Therefore the next statement sets variable 'max' to 1 for the max()
** aggregate, or 0 for min().
*/
max = ((sqlite3_user_data(context)==(void *)-1)?1:0);
cmp = sqlite3MemCompare(pBest, pArg, 0);
if( (max && cmp<0) || (!max && cmp>0) ){
sqlite3VdbeMemCopy(pBest, pArg);
}
}else{
sqlite3VdbeMemCopy(pBest, pArg);
}
}
static void minMaxFinalize(sqlite3_context *context){
sqlite3_value *pRes;
pRes = (sqlite3_value *)sqlite3_get_context(context, sizeof(Mem));
if( pRes->flags ){
sqlite3_result(context, pRes);
}
}
/*
** 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 sqlite3RegisterBuiltinFunctions(sqlite *db){
static struct {
char *zName;
signed char nArg;
u8 argType; /* 0: none. 1: db 2: (-1) */
void (*xFunc)(sqlite3_context*,int,sqlite3_value **);
} aFuncs[] = {
{ "min", -1, 0, minmaxFunc },
{ "min", 0, 0, 0 },
{ "max", -1, 2, minmaxFunc },
{ "max", 0, 2, 0 },
{ "typeof", 1, 0, typeofFunc },
{ "classof", 1, 0, typeofFunc }, /* FIX ME: hack */
{ "length", 1, 0, lengthFunc },
{ "substr", 3, 0, substrFunc },
{ "abs", 1, 0, absFunc },
{ "round", 1, 0, roundFunc },
{ "round", 2, 0, roundFunc },
{ "upper", 1, 0, upperFunc },
{ "lower", 1, 0, lowerFunc },
{ "coalesce", -1, 0, ifnullFunc },
{ "coalesce", 0, 0, 0 },
{ "coalesce", 1, 0, 0 },
{ "ifnull", 2, 0, ifnullFunc },
{ "random", -1, 0, randomFunc },
{ "like", 2, 0, likeFunc },
{ "glob", 2, 0, globFunc },
{ "nullif", 2, 0, nullifFunc },
{ "sqlite_version", 0, 0, versionFunc},
{ "quote", 1, 0, quoteFunc },
{ "last_insert_rowid", 0, 1, last_insert_rowid },
{ "change_count", 0, 1, change_count },
{ "last_statement_change_count", 0, 1, last_statement_change_count },
#ifdef SQLITE_SOUNDEX
{ "soundex", 1, 0, soundexFunc},
#endif
#ifdef SQLITE_TEST
{ "randstr", 2, 0, randStr },
#endif
};
static struct {
char *zName;
signed char nArg;
u8 argType;
void (*xStep)(sqlite3_context*,int,sqlite3_value**);
void (*xFinalize)(sqlite3_context*);
} aAggs[] = {
{ "min", 1, 0, minmaxStep, minMaxFinalize },
{ "max", 1, 2, minmaxStep, minMaxFinalize },
{ "sum", 1, 0, sumStep, sumFinalize },
{ "avg", 1, 0, sumStep, avgFinalize },
{ "count", 0, 0, countStep, countFinalize },
{ "count", 1, 0, countStep, countFinalize },
#if 0
{ "stddev", 1, 0, stdDevStep, stdDevFinalize },
#endif
};
int i;
for(i=0; i<sizeof(aFuncs)/sizeof(aFuncs[0]); i++){
void *pArg = aFuncs[i].argType==2 ? (void*)(-1) : db;
sqlite3_create_function(db, aFuncs[i].zName, aFuncs[i].nArg, 0, 0,
pArg, aFuncs[i].xFunc, 0, 0);
}
for(i=0; i<sizeof(aAggs)/sizeof(aAggs[0]); i++){
void *pArg = aAggs[i].argType==2 ? (void*)(-1) : db;
sqlite3_create_function(db, aAggs[i].zName, aAggs[i].nArg, 0, 0, pArg,
0, aAggs[i].xStep, aAggs[i].xFinalize);
}
sqlite3RegisterDateTimeFunctions(db);
}