/*
** Copyright (c) 1999, 2000 D. Richard Hipp
**
** This program is free software; you can redistribute it and/or
** modify it under the terms of the GNU General Public
** License as published by the Free Software Foundation; either
** version 2 of the License, or (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
** General Public License for more details.
**
** You should have received a copy of the GNU General Public
** License along with this library; if not, write to the
** Free Software Foundation, Inc., 59 Temple Place - Suite 330,
** Boston, MA 02111-1307, USA.
**
** Author contact information:
** drh@hwaci.com
** http://www.hwaci.com/drh/
**
*************************************************************************
** This file contains C code routines used for processing expressions
**
** $Id: expr.c,v 1.4 2000/06/03 19:19:41 drh Exp $
*/
#include "sqliteInt.h"
/*
** This routine walks an expression tree and resolves references to
** table fields. Nodes of the form ID.ID or ID resolve into an
** index to the table in the table list and a field offset. The opcode
** for such nodes is changed to TK_FIELD. The iTable value is changed
** to the index of the referenced table in pTabList, and the iField value
** is changed to the index of the field of the referenced table.
**
** Unknown fields 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, IdList *pTabList, Expr *pExpr){
if( pExpr==0 ) return 0;
switch( pExpr->op ){
/* A lone identifier */
case TK_ID: {
int cnt = 0; /* Number of matches */
int i; /* Loop counter */
char *z = 0;
sqliteSetNString(&z, pExpr->token.z, pExpr->token.n, 0);
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;
pExpr->iField = j;
}
}
}
sqliteFree(z);
if( cnt==0 ){
sqliteSetNString(&pParse->zErrMsg, "no such field: ", -1,
pExpr->token.z, pExpr->token.n, 0);
pParse->nErr++;
return 1;
}else if( cnt>1 ){
sqliteSetNString(&pParse->zErrMsg, "ambiguous field name: ", -1,
pExpr->token.z, pExpr->token.n, 0);
pParse->nErr++;
return 1;
}
pExpr->op = TK_FIELD;
break;
}
/* A table name and field name: ID.ID */
case TK_DOT: {
int cnt = 0; /* Number of matches */
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 );
assert( pRight && pRight->op==TK_ID );
zLeft = 0;
sqliteSetNString(&zLeft, pLeft->token.z, pLeft->token.n, 0);
zRight = 0;
sqliteSetNString(&zRight, pRight->token.z, pRight->token.n, 0);
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;
for(j=0; j<pTab->nCol; j++){
if( sqliteStrICmp(pTab->aCol[j].zName, zRight)==0 ){
cnt++;
pExpr->iTable = i;
pExpr->iField = j;
}
}
}
sqliteFree(zLeft);
sqliteFree(zRight);
if( cnt==0 ){
sqliteSetNString(&pParse->zErrMsg, "no such field: ", -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 field 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_FIELD;
break;
}
/* For all else, just recursively walk the tree */
default: {
if( pExpr->pLeft
&& sqliteExprResolveIds(pParse, pTabList, pExpr->pLeft) ){
return 1;
}
if( pExpr->pRight
&& sqliteExprResolveIds(pParse, pTabList, pExpr->pRight) ){
return 1;
}
if( pExpr->pList ){
int i;
ExprList *pList = pExpr->pList;
for(i=0; i<pList->nExpr; i++){
if( sqliteExprResolveIds(pParse, pTabList, 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 },
};
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;
if( pIsAgg ) *pIsAgg = 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 is_agg = 0;
int i;
switch( id ){
case FN_Unknown: {
no_such_func = 1;
break;
}
case FN_Count: {
no_such_func = !allowAgg;
too_many_args = n>1;
is_agg = 1;
break;
}
case FN_Max:
case FN_Min: {
too_few_args = allowAgg ? n<1 : n<2;
is_agg = n==1;
break;
}
case FN_Sum: {
no_such_func = !allowAgg;
too_many_args = n>1;
too_few_args = n<1;
is_agg = 1;
break;
}
default: break;
}
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++;
}
if( is_agg && pIsAgg ) *pIsAgg = 1;
for(i=0; nErr==0 && i<n; i++){
nErr = sqliteExprCheck(pParse, pExpr->pList->a[i].pExpr, 0, 0);
}
}
default: {
if( pExpr->pLeft ){
nErr = sqliteExprCheck(pParse, pExpr->pLeft, 0, 0);
}
if( nErr==0 && pExpr->pRight ){
nErr = sqliteExprCheck(pParse, pExpr->pRight, 0, 0);
}
break;
}
}
return nErr;
}
/*
** Generate code into the current Vdbe to evaluate the given
** expression and leave the result on the stack.
*/
void sqliteExprCode(Parse *pParse, Expr *pExpr){
Vdbe *v = pParse->pVdbe;
int op;
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;
default: break;
}
switch( pExpr->op ){
case TK_FIELD: {
sqliteVdbeAddOp(v, OP_Field, pExpr->iTable, pExpr->iField, 0, 0);
break;
}
case TK_INTEGER: {
int i = atoi(pExpr->token.z);
sqliteVdbeAddOp(v, OP_Integer, i, 0, 0, 0);
break;
}
case TK_FLOAT: {
int addr = sqliteVdbeAddOp(v, OP_String, 0, 0, 0, 0);
sqliteVdbeChangeP3(v, addr, pExpr->token.z, pExpr->token.n);
break;
}
case TK_STRING: {
int addr = sqliteVdbeAddOp(v, OP_String, 0, 0, 0, 0);
sqliteVdbeChangeP3(v, addr, pExpr->token.z, pExpr->token.n);
sqliteVdbeDequoteP3(v, addr);
break;
}
case TK_NULL: {
sqliteVdbeAddOp(v, OP_String, 0, 0, "", 0);
break;
}
case TK_AND:
case TK_OR:
case TK_PLUS:
case TK_STAR:
case TK_MINUS:
case TK_SLASH: {
sqliteExprCode(pParse, pExpr->pLeft);
sqliteExprCode(pParse, pExpr->pRight);
sqliteVdbeAddOp(v, op, 0, 0, 0, 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, 0, 0);
sqliteExprCode(pParse, pExpr->pLeft);
sqliteExprCode(pParse, pExpr->pRight);
dest = sqliteVdbeCurrentAddr(v) + 2;
sqliteVdbeAddOp(v, op, 0, dest, 0, 0);
sqliteVdbeAddOp(v, OP_AddImm, -1, 0, 0, 0);
break;
}
case TK_NOT:
case TK_UMINUS: {
sqliteExprCode(pParse, pExpr->pLeft);
sqliteVdbeAddOp(v, op, 0, 0, 0, 0);
break;
}
case TK_ISNULL:
case TK_NOTNULL: {
int dest;
sqliteVdbeAddOp(v, OP_Integer, 1, 0, 0, 0);
sqliteExprCode(pParse, pExpr->pLeft);
dest = sqliteVdbeCurrentAddr(v) + 2;
sqliteVdbeAddOp(v, op, 0, dest, 0, 0);
sqliteVdbeAddOp(v, OP_AddImm, -1, 0, 0, 0);
break;
}
case TK_FUNCTION: {
int id = sqliteFuncId(&pExpr->token);
int op;
int i;
ExprList *pList = pExpr->pList;
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, 0, 0);
}
}
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;
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, 0, 0);
break;
}
case TK_ISNULL:
case TK_NOTNULL: {
sqliteExprCode(pParse, pExpr->pLeft);
sqliteVdbeAddOp(v, op, 0, dest, 0, 0);
break;
}
default: {
sqliteExprCode(pParse, pExpr);
sqliteVdbeAddOp(v, OP_If, 0, dest, 0, 0);
break;
}
}
}
/*
** Generate code for 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;
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, 0, 0);
break;
}
case TK_LIKE:
case TK_GLOB: {
sqliteExprCode(pParse, pExpr->pLeft);
sqliteExprCode(pParse, pExpr->pRight);
sqliteVdbeAddOp(v, op, 1, dest, 0, 0);
break;
}
case TK_ISNULL:
case TK_NOTNULL: {
sqliteExprCode(pParse, pExpr->pLeft);
sqliteVdbeAddOp(v, op, 0, dest, 0, 0);
break;
}
default: {
sqliteExprCode(pParse, pExpr);
sqliteVdbeAddOp(v, OP_Not, 0, 0, 0, 0);
sqliteVdbeAddOp(v, OP_If, 0, dest, 0, 0);
break;
}
}
}