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ff78bd2f07647a60c45d80af11687e7d32122a98
sqlite/src/expr.c
drh ff78bd2f07 Bug fixes in the VIEW implementation. (CVS 396) 
FossilOrigin-Name: 668ef6380eba256ef82477b63aef850249a619a0
2002-02-27 01:47:11 +00:00

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/*
** 2001 September 15
**
** 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 routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
** $Id: expr.c,v 1.46 2002/02/27 01:47:12 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
** is responsible for making sure the node eventually gets freed.
*/
Expr *sqliteExpr(int op, Expr *pLeft, Expr *pRight, Token *pToken){
Expr *pNew;
pNew = sqliteMalloc( sizeof(Expr) );
if( pNew==0 ){
sqliteExprDelete(pLeft);
sqliteExprDelete(pRight);
return 0;
}
pNew->op = op;
pNew->pLeft = pLeft;
pNew->pRight = pRight;
if( pToken ){
pNew->token = *pToken;
}else{
pNew->token.z = 0;
pNew->token.n = 0;
}
if( pLeft && pRight ){
sqliteExprSpan(pNew, &pLeft->span, &pRight->span);
}else{
pNew->span = pNew->token;
}
return pNew;
}
/*
** Set the Expr.token field of the given expression to span all
** text between the two given tokens.
*/
void sqliteExprSpan(Expr *pExpr, Token *pLeft, Token *pRight){
if( pExpr ){
pExpr->span.z = pLeft->z;
pExpr->span.n = pRight->n + Addr(pRight->z) - Addr(pLeft->z);
}
}
/*
** Construct a new expression node for a function with multiple
** arguments.
*/
Expr *sqliteExprFunction(ExprList *pList, Token *pToken){
Expr *pNew;
pNew = sqliteMalloc( sizeof(Expr) );
if( pNew==0 ){
sqliteExprListDelete(pList);
return 0;
}
pNew->op = TK_FUNCTION;
pNew->pList = pList;
if( pToken ){
pNew->token = *pToken;
}else{
pNew->token.z = 0;
pNew->token.n = 0;
}
return pNew;
}
/*
** Recursively delete an expression tree.
*/
void sqliteExprDelete(Expr *p){
if( p==0 ) return;
if( p->op!=TK_AS ){
if( p->pLeft ) sqliteExprDelete(p->pLeft);
if( p->pRight ) sqliteExprDelete(p->pRight);
}
if( p->pList ) sqliteExprListDelete(p->pList);
if( p->pSelect ) sqliteSelectDelete(p->pSelect);
sqliteFree(p);
}
/*
** The following group of functions are used to translate the string
** pointers of tokens in expression from one buffer to another.
**
** Normally, the Expr.token.z and Expr.span.z fields point into the
** original input buffer of an SQL statement. This is usually OK
** since the SQL statement is executed and the expression is deleted
** before the input buffer is freed. Making the tokens point to the
** original input buffer saves many calls to malloc() and thus helps
** the library to run faster.
**
** 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
** presistent copy of the input buffer is done by the calling routine.
*/
void sqliteExprMoveStrings(Expr *p, int offset){
if( p==0 ) return;
if( p->token.z ) p->token.z += offset;
if( p->span.z ) p->span.z += offset;
if( p->pLeft ) sqliteExprMoveStrings(p->pLeft, offset);
if( p->pRight ) sqliteExprMoveStrings(p->pRight, offset);
if( p->pList ) sqliteExprListMoveStrings(p->pList, offset);
if( p->pSelect ) sqliteSelectMoveStrings(p->pSelect, offset);
}
void sqliteExprListMoveStrings(ExprList *pList, int offset){
int i;
if( pList==0 ) return;
for(i=0; i<pList->nExpr; i++){
sqliteExprMoveStrings(pList->a[i].pExpr, offset);
}
}
void sqliteSelectMoveStrings(Select *pSelect, int offset){
if( pSelect==0 ) return;
sqliteExprListMoveStrings(pSelect->pEList, offset);
sqliteExprMoveStrings(pSelect->pWhere, offset);
sqliteExprListMoveStrings(pSelect->pGroupBy, offset);
sqliteExprMoveStrings(pSelect->pHaving, offset);
sqliteExprListMoveStrings(pSelect->pOrderBy, offset);
sqliteSelectMoveStrings(pSelect->pPrior, offset);
}
/*
** The following group of routines make deep copies of expressions,
** expression lists, ID lists, and select statements. The copies can
** be deleted (by being passed to their respective ...Delete() routines)
** without effecting the originals.
**
** Note, however, that the Expr.token.z and Expr.span.z fields point to
** string space that is allocated separately from the expression tree
** itself. These routines do NOT duplicate that string space.
**
** The expression list and ID list return by sqliteExprListDup() and
** sqliteIdListDup() can not be further expanded by subsequent calls
** to sqliteExprListAppend() or sqliteIdListAppend().
**
** Any tables that the ID list might point to are not duplicated.
*/
Expr *sqliteExprDup(Expr *p){
Expr *pNew;
if( p==0 ) return 0;
pNew = sqliteMalloc( sizeof(*p) );
if( pNew==0 ) return 0;
pNew->op = p->op;
pNew->pLeft = sqliteExprDup(p->pLeft);
pNew->pRight = sqliteExprDup(p->pRight);
pNew->pList = sqliteExprListDup(p->pList);
pNew->token = p->token;
pNew->span = p->span;
pNew->pSelect = sqliteSelectDup(p->pSelect);
return pNew;
}
ExprList *sqliteExprListDup(ExprList *p){
ExprList *pNew;
int i;
if( p==0 ) return 0;
pNew = sqliteMalloc( sizeof(*pNew) );
if( pNew==0 ) return 0;
pNew->nExpr = p->nExpr;
pNew->a = sqliteMalloc( p->nExpr*sizeof(p->a[0]) );
for(i=0; i<p->nExpr; i++){
pNew->a[i].pExpr = sqliteExprDup(p->a[i].pExpr);
pNew->a[i].zName = sqliteStrDup(p->a[i].zName);
pNew->a[i].sortOrder = p->a[i].sortOrder;
pNew->a[i].isAgg = p->a[i].isAgg;
pNew->a[i].done = 0;
}
return pNew;
}
IdList *sqliteIdListDup(IdList *p){
IdList *pNew;
int i;
if( p==0 ) return 0;
pNew = sqliteMalloc( sizeof(*pNew) );
if( pNew==0 ) return 0;
pNew->nId = p->nId;
pNew->a = sqliteMalloc( p->nId*sizeof(p->a[0]) );
for(i=0; i<p->nId; i++){
pNew->a[i].zName = sqliteStrDup(p->a[i].zName);
pNew->a[i].zAlias = sqliteStrDup(p->a[i].zAlias);
pNew->a[i].idx = p->a[i].idx;
pNew->a[i].pTab = 0;
pNew->a[i].pSelect = sqliteSelectDup(p->a[i].pSelect);
}
return pNew;
}
Select *sqliteSelectDup(Select *p){
Select *pNew;
if( p==0 ) return 0;
pNew = sqliteMalloc( sizeof(*p) );
if( pNew==0 ) return 0;
pNew->isDistinct = p->isDistinct;
pNew->pEList = sqliteExprListDup(p->pEList);
pNew->pSrc = sqliteIdListDup(p->pSrc);
pNew->pWhere = sqliteExprDup(p->pWhere);
pNew->pGroupBy = sqliteExprListDup(p->pGroupBy);
pNew->pHaving = sqliteExprDup(p->pHaving);
pNew->pOrderBy = sqliteExprListDup(p->pOrderBy);
pNew->op = p->op;
pNew->pPrior = sqliteSelectDup(p->pPrior);
pNew->nLimit = p->nLimit;
pNew->nOffset = p->nOffset;
pNew->zSelect = 0;
return pNew;
}
/*
** Add a new element to the end of an expression list. If pList is
** initially NULL, then create a new expression list.
*/
ExprList *sqliteExprListAppend(ExprList *pList, Expr *pExpr, Token *pName){
int i;
if( pList==0 ){
pList = sqliteMalloc( sizeof(ExprList) );
if( pList==0 ){
sqliteExprDelete(pExpr);
return 0;
}
}
if( (pList->nExpr & 7)==0 ){
int n = pList->nExpr + 8;
struct ExprList_item *a;
a = sqliteRealloc(pList->a, n*sizeof(pList->a[0]));
if( a==0 ){
sqliteExprDelete(pExpr);
return pList;
}
pList->a = a;
}
if( pExpr || pName ){
i = pList->nExpr++;
pList->a[i].pExpr = pExpr;
pList->a[i].zName = 0;
if( pName ){
sqliteSetNString(&pList->a[i].zName, pName->z, pName->n, 0);
sqliteDequote(pList->a[i].zName);
}
}
return pList;
}
/*
** Delete an entire expression list.
*/
void sqliteExprListDelete(ExprList *pList){
int i;
if( pList==0 ) return;
for(i=0; i<pList->nExpr; i++){
sqliteExprDelete(pList->a[i].pExpr);
sqliteFree(pList->a[i].zName);
}
sqliteFree(pList->a);
sqliteFree(pList);
}
/*
** Walk an expression tree. Return 1 if the expression is constant
** and 0 if it involves variables.
*/
int sqliteExprIsConstant(Expr *p){
switch( p->op ){
case TK_ID:
case TK_COLUMN:
case TK_DOT:
return 0;
case TK_INTEGER:
case TK_FLOAT:
case TK_STRING:
return 1;
default: {
if( p->pLeft && !sqliteExprIsConstant(p->pLeft) ) return 0;
if( p->pRight && !sqliteExprIsConstant(p->pRight) ) return 0;
if( p->pList ){
int i;
for(i=0; i<p->pList->nExpr; i++){
if( !sqliteExprIsConstant(p->pList->a[i].pExpr) ) return 0;
}
}
return p->pLeft!=0 || p->pRight!=0 || (p->pList && p->pList->nExpr>0);
}
}
return 0;
}
/*
** Walk the expression tree and process operators of the form:
**
** expr IN (SELECT ...)
**
** These operators have to be processed before column names are
** resolved because each such operator increments pParse->nTab
** to reserve cursor numbers for its own use. But pParse->nTab
** needs to be constant once we begin resolving column names. For
** that reason, this procedure needs to be called on every expression
** before sqliteExprResolveIds() is called on any expression.
**
** Actually, the processing of IN-SELECT is only started by this
** routine. This routine allocates a cursor number to the IN-SELECT
** and then moves on. The code generation is done by
** sqliteExprResolveIds() which must be called afterwards.
*/
void sqliteExprResolveInSelect(Parse *pParse, Expr *pExpr){
if( pExpr==0 ) return;
if( pExpr->op==TK_IN && pExpr->pSelect!=0 ){
pExpr->iTable = pParse->nTab++;
}else{
if( pExpr->pLeft ) sqliteExprResolveInSelect(pParse, pExpr->pLeft);
if( pExpr->pRight ) sqliteExprResolveInSelect(pParse, pExpr->pRight);
if( pExpr->pList ){
int i;
ExprList *pList = pExpr->pList;
for(i=0; i<pList->nExpr; i++){
sqliteExprResolveInSelect(pParse, pList->a[i].pExpr);
}
}
}
}
/*
** Return TRUE if the given string is a row-id column name.
*/
static int sqliteIsRowid(const char *z){
if( sqliteStrICmp(z, "_ROWID_")==0 ) return 1;
if( sqliteStrICmp(z, "ROWID")==0 ) return 1;
if( sqliteStrICmp(z, "OID")==0 ) return 1;
return 0;
}
/*
** This routine walks an expression tree and resolves references to
** table columns. Nodes of the form ID.ID or ID resolve into an
** index to the table in the table list and a column offset. The
** Expr.opcode for such nodes is changed to TK_COLUMN. The Expr.iTable
** value is changed to the index of the referenced table in pTabList
** plus the pParse->nTab value. This value will ultimately become the
** VDBE cursor number for a cursor that is pointing into the referenced
** table. The Expr.iColumn value is changed to the index of the column
** of the referenced table. The Expr.iColumn value for the special
** ROWID column is -1. Any INTEGER PRIMARY KEY column is tried as an
** alias for ROWID.
**
** We also check for instances of the IN operator. IN comes in two
** forms:
**
** expr IN (exprlist)
** and
** expr IN (SELECT ...)
**
** The first form is handled by creating a set holding the list
** of allowed values. The second form causes the SELECT to generate
** a temporary table.
**
** This routine also looks for scalar SELECTs that are part of an expression.
** If it finds any, it generates code to write the value of that select
** into a memory cell.
**
** Unknown columns or tables provoke an error. The function returns
** the number of errors seen and leaves an error message on pParse->zErrMsg.
*/
int sqliteExprResolveIds(
Parse *pParse, /* The parser context */
IdList *pTabList, /* List of tables used to resolve column names */
ExprList *pEList, /* List of expressions used to resolve "AS" */
Expr *pExpr /* The expression to be analyzed. */
){
if( pExpr==0 || pTabList==0 ) return 0;
switch( pExpr->op ){
/* A lone identifier. Try and match it as follows:
**
** 1. To the name of a column of one of the tables in pTabList
**
** 2. To the right side of an AS keyword in the column list of
** a SELECT statement. (For example, match against 'x' in
** "SELECT a+b AS 'x' FROM t1".)
**
** 3. One of the special names "ROWID", "OID", or "_ROWID_".
*/
case TK_ID: {
int cnt = 0; /* Number of matches */
int i; /* Loop counter */
char *z;
assert( pExpr->token.z );
z = sqliteStrNDup(pExpr->token.z, pExpr->token.n);
sqliteDequote(z);
if( z==0 ) return 1;
for(i=0; i<pTabList->nId; i++){
int j;
Table *pTab = pTabList->a[i].pTab;
if( pTab==0 ) continue;
for(j=0; j<pTab->nCol; j++){
if( sqliteStrICmp(pTab->aCol[j].zName, z)==0 ){
cnt++;
pExpr->iTable = i + pParse->nTab;
if( j==pTab->iPKey ){
/* Substitute the record number for the INTEGER PRIMARY KEY */
pExpr->iColumn = -1;
}else{
pExpr->iColumn = j;
}
pExpr->op = TK_COLUMN;
}
}
}
if( cnt==0 && pEList!=0 ){
int j;
for(j=0; j<pEList->nExpr; j++){
char *zAs = pEList->a[j].zName;
if( zAs!=0 && sqliteStrICmp(zAs, z)==0 ){
cnt++;
assert( pExpr->pLeft==0 && pExpr->pRight==0 );
pExpr->op = TK_AS;
pExpr->iColumn = j;
pExpr->pLeft = pEList->a[j].pExpr;
}
}
}
if( cnt==0 && sqliteIsRowid(z) ){
pExpr->iColumn = -1;
pExpr->iTable = pParse->nTab;
cnt = 1 + (pTabList->nId>1);
pExpr->op = TK_COLUMN;
}
sqliteFree(z);
if( cnt==0 ){
sqliteSetNString(&pParse->zErrMsg, "no such column: ", -1,
pExpr->token.z, pExpr->token.n, 0);
pParse->nErr++;
return 1;
}else if( cnt>1 ){
sqliteSetNString(&pParse->zErrMsg, "ambiguous column name: ", -1,
pExpr->token.z, pExpr->token.n, 0);
pParse->nErr++;
return 1;
}
break;
}
/* A table name and column name: ID.ID */
case TK_DOT: {
int cnt = 0; /* Number of matches */
int cntTab = 0; /* Number of matching tables */
int i; /* Loop counter */
Expr *pLeft, *pRight; /* Left and right subbranches of the expr */
char *zLeft, *zRight; /* Text of an identifier */
pLeft = pExpr->pLeft;
pRight = pExpr->pRight;
assert( pLeft && pLeft->op==TK_ID && pLeft->token.z );
assert( pRight && pRight->op==TK_ID && pRight->token.z );
zLeft = sqliteStrNDup(pLeft->token.z, pLeft->token.n);
zRight = sqliteStrNDup(pRight->token.z, pRight->token.n);
if( zLeft==0 || zRight==0 ){
sqliteFree(zLeft);
sqliteFree(zRight);
return 1;
}
sqliteDequote(zLeft);
sqliteDequote(zRight);
pExpr->iTable = -1;
for(i=0; i<pTabList->nId; i++){
int j;
char *zTab;
Table *pTab = pTabList->a[i].pTab;
if( pTab==0 ) continue;
if( pTabList->a[i].zAlias ){
zTab = pTabList->a[i].zAlias;
}else{
zTab = pTab->zName;
}
if( sqliteStrICmp(zTab, zLeft)!=0 ) continue;
if( 0==(cntTab++) ) pExpr->iTable = i + pParse->nTab;
for(j=0; j<pTab->nCol; j++){
if( sqliteStrICmp(pTab->aCol[j].zName, zRight)==0 ){
cnt++;
pExpr->iTable = i + pParse->nTab;
if( j==pTab->iPKey ){
/* Substitute the record number for the INTEGER PRIMARY KEY */
pExpr->iColumn = -1;
}else{
pExpr->iColumn = j;
}
}
}
}
if( cnt==0 && cntTab==1 && sqliteIsRowid(zRight) ){
cnt = 1;
pExpr->iColumn = -1;
}
sqliteFree(zLeft);
sqliteFree(zRight);
if( cnt==0 ){
sqliteSetNString(&pParse->zErrMsg, "no such column: ", -1,
pLeft->token.z, pLeft->token.n, ".", 1,
pRight->token.z, pRight->token.n, 0);
pParse->nErr++;
return 1;
}else if( cnt>1 ){
sqliteSetNString(&pParse->zErrMsg, "ambiguous column name: ", -1,
pLeft->token.z, pLeft->token.n, ".", 1,
pRight->token.z, pRight->token.n, 0);
pParse->nErr++;
return 1;
}
sqliteExprDelete(pLeft);
pExpr->pLeft = 0;
sqliteExprDelete(pRight);
pExpr->pRight = 0;
pExpr->op = TK_COLUMN;
break;
}
case TK_IN: {
Vdbe *v = sqliteGetVdbe(pParse);
if( v==0 ) return 1;
if( sqliteExprResolveIds(pParse, pTabList, pEList, pExpr->pLeft) ){
return 1;
}
if( pExpr->pSelect ){
/* Case 1: expr IN (SELECT ...)
**
** Generate code to write the results of the select into a temporary
** table. The cursor number of the temporary table has already
** been put in iTable by sqliteExprResolveInSelect().
*/
sqliteVdbeAddOp(v, OP_OpenTemp, pExpr->iTable, 1);
if( sqliteSelect(pParse, pExpr->pSelect, SRT_Set, pExpr->iTable) );
}else if( pExpr->pList ){
/* Case 2: expr IN (exprlist)
**
** Create a set to put the exprlist values in. The Set id is stored
** in iTable.
*/
int i, iSet;
for(i=0; i<pExpr->pList->nExpr; i++){
Expr *pE2 = pExpr->pList->a[i].pExpr;
if( !sqliteExprIsConstant(pE2) ){
sqliteSetString(&pParse->zErrMsg,
"right-hand side of IN operator must be constant", 0);
pParse->nErr++;
return 1;
}
if( sqliteExprCheck(pParse, pE2, 0, 0) ){
return 1;
}
}
iSet = pExpr->iTable = pParse->nSet++;
for(i=0; i<pExpr->pList->nExpr; i++){
Expr *pE2 = pExpr->pList->a[i].pExpr;
switch( pE2->op ){
case TK_FLOAT:
case TK_INTEGER:
case TK_STRING: {
int addr = sqliteVdbeAddOp(v, OP_SetInsert, iSet, 0);
assert( pE2->token.z );
sqliteVdbeChangeP3(v, addr, pE2->token.z, pE2->token.n);
sqliteVdbeDequoteP3(v, addr);
break;
}
default: {
sqliteExprCode(pParse, pE2);
sqliteVdbeAddOp(v, OP_SetInsert, iSet, 0);
break;
}
}
}
}
break;
}
case TK_SELECT: {
/* This has to be a scalar SELECT. Generate code to put the
** value of this select in a memory cell and record the number
** of the memory cell in iColumn.
*/
pExpr->iColumn = pParse->nMem++;
if( sqliteSelect(pParse, pExpr->pSelect, SRT_Mem, pExpr->iColumn) ){
return 1;
}
break;
}
/* For all else, just recursively walk the tree */
default: {
if( pExpr->pLeft
&& sqliteExprResolveIds(pParse, pTabList, pEList, pExpr->pLeft) ){
return 1;
}
if( pExpr->pRight
&& sqliteExprResolveIds(pParse, pTabList, pEList, pExpr->pRight) ){
return 1;
}
if( pExpr->pList ){
int i;
ExprList *pList = pExpr->pList;
for(i=0; i<pList->nExpr; i++){
if( sqliteExprResolveIds(pParse,pTabList,pEList,pList->a[i].pExpr) ){
return 1;
}
}
}
}
}
return 0;
}
#if 0 /* NOT USED */
/*
** Compare a token against a string. Return TRUE if they match.
*/
static int sqliteTokenCmp(Token *pToken, const char *zStr){
int n = strlen(zStr);
if( n!=pToken->n ) return 0;
return sqliteStrNICmp(pToken->z, zStr, n)==0;
}
#endif
/*
** Convert a function name into its integer identifier. Return the
** identifier. Return FN_Unknown if the function name is unknown.
*/
int sqliteFuncId(Token *pToken){
static const struct {
char *zName;
int len;
int id;
} aFunc[] = {
{ "count", 5, FN_Count },
{ "min", 3, FN_Min },
{ "max", 3, FN_Max },
{ "sum", 3, FN_Sum },
{ "avg", 3, FN_Avg },
{ "length", 6, FN_Length },
{ "substr", 6, FN_Substr },
{ "abs", 3, FN_Abs },
{ "round", 5, FN_Round },
};
int i;
for(i=0; i<ArraySize(aFunc); i++){
if( aFunc[i].len==pToken->n
&& sqliteStrNICmp(pToken->z, aFunc[i].zName, aFunc[i].len)==0 ){
return aFunc[i].id;
}
}
return FN_Unknown;
}
/*
** Error check the functions in an expression. Make sure all
** function names are recognized and all functions have the correct
** number of arguments. Leave an error message in pParse->zErrMsg
** if anything is amiss. Return the number of errors.
**
** if pIsAgg is not null and this expression is an aggregate function
** (like count(*) or max(value)) then write a 1 into *pIsAgg.
*/
int sqliteExprCheck(Parse *pParse, Expr *pExpr, int allowAgg, int *pIsAgg){
int nErr = 0;
if( pExpr==0 ) return 0;
switch( pExpr->op ){
case TK_FUNCTION: {
int id = sqliteFuncId(&pExpr->token);
int n = pExpr->pList ? pExpr->pList->nExpr : 0;
int no_such_func = 0;
int too_many_args = 0;
int too_few_args = 0;
int wrong_num_args = 0;
int is_agg = 0;
int i;
pExpr->iColumn = id;
switch( id ){
case FN_Unknown: {
UserFunc *pUser = sqliteFindUserFunction(pParse->db,
pExpr->token.z, pExpr->token.n, n, 0);
if( pUser==0 ){
pUser = sqliteFindUserFunction(pParse->db,
pExpr->token.z, pExpr->token.n, -1, 0);
if( pUser==0 ){
no_such_func = 1;
}else{
wrong_num_args = 1;
}
}else{
is_agg = pUser->xFunc==0;
}
break;
}
case FN_Count: {
too_many_args = n>1;
is_agg = 1;
break;
}
case FN_Max:
case FN_Min: {
too_few_args = n<1;
is_agg = n==1;
break;
}
case FN_Avg:
case FN_Sum: {
too_many_args = n>1;
too_few_args = n<1;
is_agg = 1;
break;
}
case FN_Abs:
case FN_Length: {
too_few_args = n<1;
too_many_args = n>1;
break;
}
case FN_Round: {
too_few_args = n<1;
too_many_args = n>2;
break;
}
case FN_Substr: {
too_few_args = n<3;
too_many_args = n>3;
break;
}
default: break;
}
if( is_agg && !allowAgg ){
sqliteSetNString(&pParse->zErrMsg, "misuse of aggregate function ", -1,
pExpr->token.z, pExpr->token.n, "()", 2, 0);
pParse->nErr++;
nErr++;
is_agg = 0;
}else if( no_such_func ){
sqliteSetNString(&pParse->zErrMsg, "no such function: ", -1,
pExpr->token.z, pExpr->token.n, 0);
pParse->nErr++;
nErr++;
}else if( too_many_args ){
sqliteSetNString(&pParse->zErrMsg, "too many arguments to function ",-1,
pExpr->token.z, pExpr->token.n, "()", 2, 0);
pParse->nErr++;
nErr++;
}else if( too_few_args ){
sqliteSetNString(&pParse->zErrMsg, "too few arguments to function ",-1,
pExpr->token.z, pExpr->token.n, "()", 2, 0);
pParse->nErr++;
nErr++;
}else if( wrong_num_args ){
sqliteSetNString(&pParse->zErrMsg,
"wrong number of arguments to function ",-1,
pExpr->token.z, pExpr->token.n, "()", 2, 0);
pParse->nErr++;
nErr++;
}
if( is_agg ) pExpr->op = TK_AGG_FUNCTION;
if( is_agg && pIsAgg ) *pIsAgg = 1;
for(i=0; nErr==0 && i<n; i++){
nErr = sqliteExprCheck(pParse, pExpr->pList->a[i].pExpr,
allowAgg && !is_agg, pIsAgg);
}
}
default: {
if( pExpr->pLeft ){
nErr = sqliteExprCheck(pParse, pExpr->pLeft, allowAgg, pIsAgg);
}
if( nErr==0 && pExpr->pRight ){
nErr = sqliteExprCheck(pParse, pExpr->pRight, allowAgg, pIsAgg);
}
if( nErr==0 && pExpr->pList ){
int n = pExpr->pList->nExpr;
int i;
for(i=0; nErr==0 && i<n; i++){
Expr *pE2 = pExpr->pList->a[i].pExpr;
nErr = sqliteExprCheck(pParse, pE2, allowAgg, pIsAgg);
}
}
break;
}
}
return nErr;
}
/*
** Generate code into the current Vdbe to evaluate the given
** expression and leave the result on the top of stack.
*/
void sqliteExprCode(Parse *pParse, Expr *pExpr){
Vdbe *v = pParse->pVdbe;
int op;
if( v==0 || pExpr==0 ) return;
switch( pExpr->op ){
case TK_PLUS: op = OP_Add; break;
case TK_MINUS: op = OP_Subtract; break;
case TK_STAR: op = OP_Multiply; break;
case TK_SLASH: op = OP_Divide; break;
case TK_AND: op = OP_And; break;
case TK_OR: op = OP_Or; break;
case TK_LT: op = OP_Lt; break;
case TK_LE: op = OP_Le; break;
case TK_GT: op = OP_Gt; break;
case TK_GE: op = OP_Ge; break;
case TK_NE: op = OP_Ne; break;
case TK_EQ: op = OP_Eq; break;
case TK_LIKE: op = OP_Like; break;
case TK_GLOB: op = OP_Glob; break;
case TK_ISNULL: op = OP_IsNull; break;
case TK_NOTNULL: op = OP_NotNull; break;
case TK_NOT: op = OP_Not; break;
case TK_UMINUS: op = OP_Negative; break;
case TK_BITAND: op = OP_BitAnd; break;
case TK_BITOR: op = OP_BitOr; break;
case TK_BITNOT: op = OP_BitNot; break;
case TK_LSHIFT: op = OP_ShiftLeft; break;
case TK_RSHIFT: op = OP_ShiftRight; break;
case TK_REM: op = OP_Remainder; break;
default: break;
}
switch( pExpr->op ){
case TK_COLUMN: {
if( pParse->useAgg ){
sqliteVdbeAddOp(v, OP_AggGet, 0, pExpr->iAgg);
}else if( pExpr->iColumn>=0 ){
sqliteVdbeAddOp(v, OP_Column, pExpr->iTable, pExpr->iColumn);
}else{
sqliteVdbeAddOp(v, OP_Recno, pExpr->iTable, 0);
}
break;
}
case TK_FLOAT:
case TK_INTEGER: {
sqliteVdbeAddOp(v, OP_String, 0, 0);
assert( pExpr->token.z );
sqliteVdbeChangeP3(v, -1, pExpr->token.z, pExpr->token.n);
break;
}
case TK_STRING: {
int addr = sqliteVdbeAddOp(v, OP_String, 0, 0);
assert( pExpr->token.z );
sqliteVdbeChangeP3(v, addr, pExpr->token.z, pExpr->token.n);
sqliteVdbeDequoteP3(v, addr);
break;
}
case TK_NULL: {
sqliteVdbeAddOp(v, OP_String, 0, 0);
break;
}
case TK_AND:
case TK_OR:
case TK_PLUS:
case TK_STAR:
case TK_MINUS:
case TK_REM:
case TK_BITAND:
case TK_BITOR:
case TK_SLASH: {
sqliteExprCode(pParse, pExpr->pLeft);
sqliteExprCode(pParse, pExpr->pRight);
sqliteVdbeAddOp(v, op, 0, 0);
break;
}
case TK_LSHIFT:
case TK_RSHIFT: {
sqliteExprCode(pParse, pExpr->pRight);
sqliteExprCode(pParse, pExpr->pLeft);
sqliteVdbeAddOp(v, op, 0, 0);
break;
}
case TK_CONCAT: {
sqliteExprCode(pParse, pExpr->pLeft);
sqliteExprCode(pParse, pExpr->pRight);
sqliteVdbeAddOp(v, OP_Concat, 2, 0);
break;
}
case TK_LT:
case TK_LE:
case TK_GT:
case TK_GE:
case TK_NE:
case TK_EQ:
case TK_LIKE:
case TK_GLOB: {
int dest;
sqliteVdbeAddOp(v, OP_Integer, 1, 0);
sqliteExprCode(pParse, pExpr->pLeft);
sqliteExprCode(pParse, pExpr->pRight);
dest = sqliteVdbeCurrentAddr(v) + 2;
sqliteVdbeAddOp(v, op, 0, dest);
sqliteVdbeAddOp(v, OP_AddImm, -1, 0);
break;
}
case TK_UMINUS: {
assert( pExpr->pLeft );
if( pExpr->pLeft->op==TK_FLOAT || pExpr->pLeft->op==TK_INTEGER ){
Token *p = &pExpr->pLeft->token;
char *z = sqliteMalloc( p->n + 2 );
sprintf(z, "-%.*s", p->n, p->z);
sqliteVdbeAddOp(v, OP_String, 0, 0);
sqliteVdbeChangeP3(v, -1, z, p->n+1);
sqliteFree(z);
break;
}
/* Fall through into TK_NOT */
}
case TK_BITNOT:
case TK_NOT: {
sqliteExprCode(pParse, pExpr->pLeft);
sqliteVdbeAddOp(v, op, 0, 0);
break;
}
case TK_ISNULL:
case TK_NOTNULL: {
int dest;
sqliteVdbeAddOp(v, OP_Integer, 1, 0);
sqliteExprCode(pParse, pExpr->pLeft);
dest = sqliteVdbeCurrentAddr(v) + 2;
sqliteVdbeAddOp(v, op, 0, dest);
sqliteVdbeAddOp(v, OP_AddImm, -1, 0);
break;
}
case TK_AGG_FUNCTION: {
sqliteVdbeAddOp(v, OP_AggGet, 0, pExpr->iAgg);
if( pExpr->iColumn==FN_Avg ){
assert( pParse->iAggCount>=0 && pParse->iAggCount<pParse->nAgg );
sqliteVdbeAddOp(v, OP_AggGet, 0, pParse->iAggCount);
sqliteVdbeAddOp(v, OP_Divide, 0, 0);
}
break;
}
case TK_FUNCTION: {
int id = pExpr->iColumn;
int op;
int i;
ExprList *pList = pExpr->pList;
switch( id ){
case FN_Min:
case FN_Max: {
op = id==FN_Min ? OP_Min : OP_Max;
for(i=0; i<pList->nExpr; i++){
sqliteExprCode(pParse, pList->a[i].pExpr);
if( i>0 ){
sqliteVdbeAddOp(v, op, 0, 0);
}
}
break;
}
case FN_Abs: {
sqliteExprCode(pParse, pList->a[0].pExpr);
sqliteVdbeAddOp(v, OP_AbsValue, 0, 0);
break;
}
case FN_Round: {
if( pList->nExpr==2 ){
sqliteExprCode(pParse, pList->a[1].pExpr);
}else{
sqliteVdbeAddOp(v, OP_Integer, 0, 0);
}
sqliteExprCode(pParse, pList->a[0].pExpr);
sqliteVdbeAddOp(v, OP_Precision, 0, 0);
break;
}
case FN_Length: {
sqliteExprCode(pParse, pList->a[0].pExpr);
sqliteVdbeAddOp(v, OP_Strlen, 0, 0);
break;
}
case FN_Substr: {
for(i=0; i<pList->nExpr; i++){
sqliteExprCode(pParse, pList->a[i].pExpr);
}
sqliteVdbeAddOp(v, OP_Substr, 0, 0);
break;
}
case FN_Unknown: {
UserFunc *pUser;
pUser = sqliteFindUserFunction(pParse->db,
pExpr->token.z, pExpr->token.n, pList->nExpr, 0);
assert( pUser!=0 );
for(i=0; i<pList->nExpr; i++){
sqliteExprCode(pParse, pList->a[i].pExpr);
}
sqliteVdbeAddOp(v, OP_UserFunc, pList->nExpr, 0);
sqliteVdbeChangeP3(v, -1, (char*)pUser->xFunc, P3_POINTER);
break;
}
default: {
/* Can't happen! */
break;
}
}
break;
}
case TK_SELECT: {
sqliteVdbeAddOp(v, OP_MemLoad, pExpr->iColumn, 0);
break;
}
case TK_IN: {
int addr;
sqliteVdbeAddOp(v, OP_Integer, 1, 0);
sqliteExprCode(pParse, pExpr->pLeft);
addr = sqliteVdbeCurrentAddr(v);
if( pExpr->pSelect ){
sqliteVdbeAddOp(v, OP_Found, pExpr->iTable, addr+2);
}else{
sqliteVdbeAddOp(v, OP_SetFound, pExpr->iTable, addr+2);
}
sqliteVdbeAddOp(v, OP_AddImm, -1, 0);
break;
}
case TK_BETWEEN: {
int lbl = sqliteVdbeMakeLabel(v);
sqliteVdbeAddOp(v, OP_Integer, 0, 0);
sqliteExprIfFalse(pParse, pExpr, lbl);
sqliteVdbeAddOp(v, OP_AddImm, 1, 0);
sqliteVdbeResolveLabel(v, lbl);
break;
}
case TK_AS: {
sqliteExprCode(pParse, pExpr->pLeft);
break;
}
}
return;
}
/*
** Generate code for a boolean expression such that a jump is made
** to the label "dest" if the expression is true but execution
** continues straight thru if the expression is false.
*/
void sqliteExprIfTrue(Parse *pParse, Expr *pExpr, int dest){
Vdbe *v = pParse->pVdbe;
int op = 0;
if( v==0 || pExpr==0 ) return;
switch( pExpr->op ){
case TK_LT: op = OP_Lt; break;
case TK_LE: op = OP_Le; break;
case TK_GT: op = OP_Gt; break;
case TK_GE: op = OP_Ge; break;
case TK_NE: op = OP_Ne; break;
case TK_EQ: op = OP_Eq; break;
case TK_LIKE: op = OP_Like; break;
case TK_GLOB: op = OP_Glob; break;
case TK_ISNULL: op = OP_IsNull; break;
case TK_NOTNULL: op = OP_NotNull; break;
default: break;
}
switch( pExpr->op ){
case TK_AND: {
int d2 = sqliteVdbeMakeLabel(v);
sqliteExprIfFalse(pParse, pExpr->pLeft, d2);
sqliteExprIfTrue(pParse, pExpr->pRight, dest);
sqliteVdbeResolveLabel(v, d2);
break;
}
case TK_OR: {
sqliteExprIfTrue(pParse, pExpr->pLeft, dest);
sqliteExprIfTrue(pParse, pExpr->pRight, dest);
break;
}
case TK_NOT: {
sqliteExprIfFalse(pParse, pExpr->pLeft, dest);
break;
}
case TK_LT:
case TK_LE:
case TK_GT:
case TK_GE:
case TK_NE:
case TK_EQ:
case TK_LIKE:
case TK_GLOB: {
sqliteExprCode(pParse, pExpr->pLeft);
sqliteExprCode(pParse, pExpr->pRight);
sqliteVdbeAddOp(v, op, 0, dest);
break;
}
case TK_ISNULL:
case TK_NOTNULL: {
sqliteExprCode(pParse, pExpr->pLeft);
sqliteVdbeAddOp(v, op, 0, dest);
break;
}
case TK_IN: {
sqliteExprCode(pParse, pExpr->pLeft);
if( pExpr->pSelect ){
sqliteVdbeAddOp(v, OP_Found, pExpr->iTable, dest);
}else{
sqliteVdbeAddOp(v, OP_SetFound, pExpr->iTable, dest);
}
break;
}
case TK_BETWEEN: {
int lbl = sqliteVdbeMakeLabel(v);
sqliteExprCode(pParse, pExpr->pLeft);
sqliteVdbeAddOp(v, OP_Dup, 0, 0);
sqliteExprCode(pParse, pExpr->pList->a[0].pExpr);
sqliteVdbeAddOp(v, OP_Lt, 0, lbl);
sqliteExprCode(pParse, pExpr->pList->a[1].pExpr);
sqliteVdbeAddOp(v, OP_Le, 0, dest);
sqliteVdbeAddOp(v, OP_Integer, 0, 0);
sqliteVdbeResolveLabel(v, lbl);
sqliteVdbeAddOp(v, OP_Pop, 1, 0);
break;
}
default: {
sqliteExprCode(pParse, pExpr);
sqliteVdbeAddOp(v, OP_If, 0, dest);
break;
}
}
}
/*
** Generate code for a boolean expression such that a jump is made
** to the label "dest" if the expression is false but execution
** continues straight thru if the expression is true.
*/
void sqliteExprIfFalse(Parse *pParse, Expr *pExpr, int dest){
Vdbe *v = pParse->pVdbe;
int op = 0;
if( v==0 || pExpr==0 ) return;
switch( pExpr->op ){
case TK_LT: op = OP_Ge; break;
case TK_LE: op = OP_Gt; break;
case TK_GT: op = OP_Le; break;
case TK_GE: op = OP_Lt; break;
case TK_NE: op = OP_Eq; break;
case TK_EQ: op = OP_Ne; break;
case TK_LIKE: op = OP_Like; break;
case TK_GLOB: op = OP_Glob; break;
case TK_ISNULL: op = OP_NotNull; break;
case TK_NOTNULL: op = OP_IsNull; break;
default: break;
}
switch( pExpr->op ){
case TK_AND: {
sqliteExprIfFalse(pParse, pExpr->pLeft, dest);
sqliteExprIfFalse(pParse, pExpr->pRight, dest);
break;
}
case TK_OR: {
int d2 = sqliteVdbeMakeLabel(v);
sqliteExprIfTrue(pParse, pExpr->pLeft, d2);
sqliteExprIfFalse(pParse, pExpr->pRight, dest);
sqliteVdbeResolveLabel(v, d2);
break;
}
case TK_NOT: {
sqliteExprIfTrue(pParse, pExpr->pLeft, dest);
break;
}
case TK_LT:
case TK_LE:
case TK_GT:
case TK_GE:
case TK_NE:
case TK_EQ: {
sqliteExprCode(pParse, pExpr->pLeft);
sqliteExprCode(pParse, pExpr->pRight);
sqliteVdbeAddOp(v, op, 0, dest);
break;
}
case TK_LIKE:
case TK_GLOB: {
sqliteExprCode(pParse, pExpr->pLeft);
sqliteExprCode(pParse, pExpr->pRight);
sqliteVdbeAddOp(v, op, 1, dest);
break;
}
case TK_ISNULL:
case TK_NOTNULL: {
sqliteExprCode(pParse, pExpr->pLeft);
sqliteVdbeAddOp(v, op, 0, dest);
break;
}
case TK_IN: {
sqliteExprCode(pParse, pExpr->pLeft);
if( pExpr->pSelect ){
sqliteVdbeAddOp(v, OP_NotFound, pExpr->iTable, dest);
}else{
sqliteVdbeAddOp(v, OP_SetNotFound, pExpr->iTable, dest);
}
break;
}
case TK_BETWEEN: {
int addr;
sqliteExprCode(pParse, pExpr->pLeft);
sqliteVdbeAddOp(v, OP_Dup, 0, 0);
sqliteExprCode(pParse, pExpr->pList->a[0].pExpr);
addr = sqliteVdbeCurrentAddr(v);
sqliteVdbeAddOp(v, OP_Ge, 0, addr+3);
sqliteVdbeAddOp(v, OP_Pop, 1, 0);
sqliteVdbeAddOp(v, OP_Goto, 0, dest);
sqliteExprCode(pParse, pExpr->pList->a[1].pExpr);
sqliteVdbeAddOp(v, OP_Gt, 0, dest);
break;
}
default: {
sqliteExprCode(pParse, pExpr);
sqliteVdbeAddOp(v, OP_Not, 0, 0);
sqliteVdbeAddOp(v, OP_If, 0, dest);
break;
}
}
}
/*
** Do a deep comparison of two expression trees. Return TRUE (non-zero)
** if they are identical and return FALSE if they differ in any way.
*/
int sqliteExprCompare(Expr *pA, Expr *pB){
int i;
if( pA==0 ){
return pB==0;
}else if( pB==0 ){
return 0;
}
if( pA->op!=pB->op ) return 0;
if( !sqliteExprCompare(pA->pLeft, pB->pLeft) ) return 0;
if( !sqliteExprCompare(pA->pRight, pB->pRight) ) return 0;
if( pA->pList ){
if( pB->pList==0 ) return 0;
if( pA->pList->nExpr!=pB->pList->nExpr ) return 0;
for(i=0; i<pA->pList->nExpr; i++){
if( !sqliteExprCompare(pA->pList->a[i].pExpr, pB->pList->a[i].pExpr) ){
return 0;
}
}
}else if( pB->pList ){
return 0;
}
if( pA->pSelect || pB->pSelect ) return 0;
if( pA->token.z ){
if( pB->token.z==0 ) return 0;
if( pB->token.n!=pA->token.n ) return 0;
if( sqliteStrNICmp(pA->token.z, pB->token.z, pA->token.n)!=0 ) return 0;
}
return 1;
}
/*
** Add a new element to the pParse->aAgg[] array and return its index.
*/
static int appendAggInfo(Parse *pParse){
if( (pParse->nAgg & 0x7)==0 ){
int amt = pParse->nAgg + 8;
AggExpr *aAgg = sqliteRealloc(pParse->aAgg, amt*sizeof(pParse->aAgg[0]));
if( aAgg==0 ){
return -1;
}
pParse->aAgg = aAgg;
}
memset(&pParse->aAgg[pParse->nAgg], 0, sizeof(pParse->aAgg[0]));
return pParse->nAgg++;
}
/*
** Analyze the given expression looking for aggregate functions and
** for variables that need to be added to the pParse->aAgg[] array.
** Make additional entries to the pParse->aAgg[] array as necessary.
**
** This routine should only be called after the expression has been
** analyzed by sqliteExprResolveIds() and sqliteExprCheck().
**
** If errors are seen, leave an error message in zErrMsg and return
** the number of errors.
*/
int sqliteExprAnalyzeAggregates(Parse *pParse, Expr *pExpr){
int i;
AggExpr *aAgg;
int nErr = 0;
if( pExpr==0 ) return 0;
switch( pExpr->op ){
case TK_COLUMN: {
aAgg = pParse->aAgg;
for(i=0; i<pParse->nAgg; i++){
if( aAgg[i].isAgg ) continue;
if( aAgg[i].pExpr->iTable==pExpr->iTable
&& aAgg[i].pExpr->iColumn==pExpr->iColumn ){
break;
}
}
if( i>=pParse->nAgg ){
i = appendAggInfo(pParse);
if( i<0 ) return 1;
pParse->aAgg[i].isAgg = 0;
pParse->aAgg[i].pExpr = pExpr;
}
pExpr->iAgg = i;
break;
}
case TK_AGG_FUNCTION: {
if( pExpr->iColumn==FN_Count || pExpr->iColumn==FN_Avg ){
if( pParse->iAggCount>=0 ){
i = pParse->iAggCount;
}else{
i = appendAggInfo(pParse);
if( i<0 ) return 1;
pParse->aAgg[i].isAgg = 1;
pParse->aAgg[i].pExpr = 0;
pParse->iAggCount = i;
}
if( pExpr->iColumn==FN_Count ){
pExpr->iAgg = i;
break;
}
}
aAgg = pParse->aAgg;
for(i=0; i<pParse->nAgg; i++){
if( !aAgg[i].isAgg ) continue;
if( sqliteExprCompare(aAgg[i].pExpr, pExpr) ){
break;
}
}
if( i>=pParse->nAgg ){
i = appendAggInfo(pParse);
if( i<0 ) return 1;
pParse->aAgg[i].isAgg = 1;
pParse->aAgg[i].pExpr = pExpr;
if( pExpr->iColumn==FN_Unknown ){
pParse->aAgg[i].pUser = sqliteFindUserFunction(pParse->db,
pExpr->token.z, pExpr->token.n, pExpr->pList->nExpr, 0);
}else{
pParse->aAgg[i].pUser = 0;
}
}
pExpr->iAgg = i;
break;
}
default: {
if( pExpr->pLeft ){
nErr = sqliteExprAnalyzeAggregates(pParse, pExpr->pLeft);
}
if( nErr==0 && pExpr->pRight ){
nErr = sqliteExprAnalyzeAggregates(pParse, pExpr->pRight);
}
if( nErr==0 && pExpr->pList ){
int n = pExpr->pList->nExpr;
int i;
for(i=0; nErr==0 && i<n; i++){
nErr = sqliteExprAnalyzeAggregates(pParse, pExpr->pList->a[i].pExpr);
}
}
break;
}
}
return nErr;
}
/*
** Locate a user function given a name and a number of arguments.
** Return a pointer to the UserFunc structure that defines that
** function, or return NULL if the function does not exist.
**
** If the createFlag argument is true, then a new (blank) UserFunc
** structure is created and liked into the "db" structure if a
** no matching function previously existed. When createFlag is true
** and the nArg parameter is -1, then only a function that accepts
** any number of arguments will be returned.
**
** If createFlag is false and nArg is -1, then the first valid
** function found is returned. A function is valid if either xFunc
** or xStep is non-zero.
*/
UserFunc *sqliteFindUserFunction(
sqlite *db, /* An open database */
const char *zName, /* Name of the function. Not null-terminated */
int nName, /* Number of characters in the name */
int nArg, /* Number of arguments. -1 means any number */
int createFlag /* Create new entry if true and does not otherwise exist */
){
UserFunc *pFirst, *p, *pMaybe;
pFirst = p = (UserFunc*)sqliteHashFind(&db->userFunc, zName, nName);
if( !createFlag && nArg<0 ){
while( p && p->xFunc==0 && p->xStep==0 ){ p = p->pNext; }
return p;
}
pMaybe = 0;
while( p && p->nArg!=nArg ){
if( p->nArg<0 && !createFlag && (p->xFunc || p->xStep) ) pMaybe = p;
p = p->pNext;
}
if( p && !createFlag && p->xFunc==0 && p->xStep==0 ){
return 0;
}
if( p==0 && pMaybe ){
assert( createFlag==0 );
return pMaybe;
}
if( p==0 && createFlag ){
p = sqliteMalloc( sizeof(*p) );
p->nArg = nArg;
p->pNext = pFirst;
sqliteHashInsert(&db->userFunc, zName, nName, (void*)p);
}
return p;
}
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