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-rw-r--r--kopete/plugins/statistics/sqlite/expr.c1927
1 files changed, 1927 insertions, 0 deletions
diff --git a/kopete/plugins/statistics/sqlite/expr.c b/kopete/plugins/statistics/sqlite/expr.c
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+++ b/kopete/plugins/statistics/sqlite/expr.c
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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.
+**
+** $Id$
+*/
+#include "sqliteInt.h"
+#include <ctype.h>
+
+/*
+** Return the 'affinity' of the expression pExpr if any.
+**
+** If pExpr is a column, a reference to a column via an 'AS' alias,
+** or a sub-select with a column as the return value, then the
+** affinity of that column is returned. Otherwise, 0x00 is returned,
+** indicating no affinity for the expression.
+**
+** i.e. the WHERE clause expresssions in the following statements all
+** have an affinity:
+**
+** CREATE TABLE t1(a);
+** SELECT * FROM t1 WHERE a;
+** SELECT a AS b FROM t1 WHERE b;
+** SELECT * FROM t1 WHERE (select a from t1);
+*/
+char sqlite3ExprAffinity(Expr *pExpr){
+ if( pExpr->op==TK_AS ){
+ return sqlite3ExprAffinity(pExpr->pLeft);
+ }
+ if( pExpr->op==TK_SELECT ){
+ return sqlite3ExprAffinity(pExpr->pSelect->pEList->a[0].pExpr);
+ }
+ return pExpr->affinity;
+}
+
+/*
+** Return the default collation sequence for the expression pExpr. If
+** there is no default collation type, return 0.
+*/
+CollSeq *sqlite3ExprCollSeq(Parse *pParse, Expr *pExpr){
+ CollSeq *pColl = 0;
+ if( pExpr ){
+ pColl = pExpr->pColl;
+ if( pExpr->op==TK_AS && !pColl ){
+ return sqlite3ExprCollSeq(pParse, pExpr->pLeft);
+ }
+ }
+ if( sqlite3CheckCollSeq(pParse, pColl) ){
+ pColl = 0;
+ }
+ return pColl;
+}
+
+/*
+** pExpr is the left operand of a comparison operator. aff2 is the
+** type affinity of the right operand. This routine returns the
+** type affinity that should be used for the comparison operator.
+*/
+char sqlite3CompareAffinity(Expr *pExpr, char aff2){
+ char aff1 = sqlite3ExprAffinity(pExpr);
+ if( aff1 && aff2 ){
+ /* Both sides of the comparison are columns. If one has numeric or
+ ** integer affinity, use that. Otherwise use no affinity.
+ */
+ if( aff1==SQLITE_AFF_INTEGER || aff2==SQLITE_AFF_INTEGER ){
+ return SQLITE_AFF_INTEGER;
+ }else if( aff1==SQLITE_AFF_NUMERIC || aff2==SQLITE_AFF_NUMERIC ){
+ return SQLITE_AFF_NUMERIC;
+ }else{
+ return SQLITE_AFF_NONE;
+ }
+ }else if( !aff1 && !aff2 ){
+ /* Neither side of the comparison is a column. Compare the
+ ** results directly.
+ */
+ /* return SQLITE_AFF_NUMERIC; // Ticket #805 */
+ return SQLITE_AFF_NONE;
+ }else{
+ /* One side is a column, the other is not. Use the columns affinity. */
+ return (aff1 + aff2);
+ }
+}
+
+/*
+** pExpr is a comparison operator. Return the type affinity that should
+** be applied to both operands prior to doing the comparison.
+*/
+static char comparisonAffinity(Expr *pExpr){
+ char aff;
+ assert( pExpr->op==TK_EQ || pExpr->op==TK_IN || pExpr->op==TK_LT ||
+ pExpr->op==TK_GT || pExpr->op==TK_GE || pExpr->op==TK_LE ||
+ pExpr->op==TK_NE );
+ assert( pExpr->pLeft );
+ aff = sqlite3ExprAffinity(pExpr->pLeft);
+ if( pExpr->pRight ){
+ aff = sqlite3CompareAffinity(pExpr->pRight, aff);
+ }
+ else if( pExpr->pSelect ){
+ aff = sqlite3CompareAffinity(pExpr->pSelect->pEList->a[0].pExpr, aff);
+ }
+ else if( !aff ){
+ aff = SQLITE_AFF_NUMERIC;
+ }
+ return aff;
+}
+
+/*
+** pExpr is a comparison expression, eg. '=', '<', IN(...) etc.
+** idx_affinity is the affinity of an indexed column. Return true
+** if the index with affinity idx_affinity may be used to implement
+** the comparison in pExpr.
+*/
+int sqlite3IndexAffinityOk(Expr *pExpr, char idx_affinity){
+ char aff = comparisonAffinity(pExpr);
+ return
+ (aff==SQLITE_AFF_NONE) ||
+ (aff==SQLITE_AFF_NUMERIC && idx_affinity==SQLITE_AFF_INTEGER) ||
+ (aff==SQLITE_AFF_INTEGER && idx_affinity==SQLITE_AFF_NUMERIC) ||
+ (aff==idx_affinity);
+}
+
+/*
+** Return the P1 value that should be used for a binary comparison
+** opcode (OP_Eq, OP_Ge etc.) used to compare pExpr1 and pExpr2.
+** If jumpIfNull is true, then set the low byte of the returned
+** P1 value to tell the opcode to jump if either expression
+** evaluates to NULL.
+*/
+static int binaryCompareP1(Expr *pExpr1, Expr *pExpr2, int jumpIfNull){
+ char aff = sqlite3ExprAffinity(pExpr2);
+ return (((int)sqlite3CompareAffinity(pExpr1, aff))<<8)+(jumpIfNull?1:0);
+}
+
+/*
+** Return a pointer to the collation sequence that should be used by
+** a binary comparison operator comparing pLeft and pRight.
+**
+** If the left hand expression has a collating sequence type, then it is
+** used. Otherwise the collation sequence for the right hand expression
+** is used, or the default (BINARY) if neither expression has a collating
+** type.
+*/
+static CollSeq* binaryCompareCollSeq(Parse *pParse, Expr *pLeft, Expr *pRight){
+ CollSeq *pColl = sqlite3ExprCollSeq(pParse, pLeft);
+ if( !pColl ){
+ pColl = sqlite3ExprCollSeq(pParse, pRight);
+ }
+ return pColl;
+}
+
+/*
+** Generate code for a comparison operator.
+*/
+static int codeCompare(
+ Parse *pParse, /* The parsing (and code generating) context */
+ Expr *pLeft, /* The left operand */
+ Expr *pRight, /* The right operand */
+ int opcode, /* The comparison opcode */
+ int dest, /* Jump here if true. */
+ int jumpIfNull /* If true, jump if either operand is NULL */
+){
+ int p1 = binaryCompareP1(pLeft, pRight, jumpIfNull);
+ CollSeq *p3 = binaryCompareCollSeq(pParse, pLeft, pRight);
+ return sqlite3VdbeOp3(pParse->pVdbe, opcode, p1, dest, (void*)p3, P3_COLLSEQ);
+}
+
+/*
+** 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 *sqlite3Expr(int op, Expr *pLeft, Expr *pRight, Token *pToken){
+ Expr *pNew;
+ pNew = sqliteMalloc( sizeof(Expr) );
+ if( pNew==0 ){
+ /* When malloc fails, we leak memory from pLeft and pRight */
+ return 0;
+ }
+ pNew->op = op;
+ pNew->pLeft = pLeft;
+ pNew->pRight = pRight;
+ if( pToken ){
+ assert( pToken->dyn==0 );
+ pNew->span = pNew->token = *pToken;
+ }else if( pLeft && pRight ){
+ sqlite3ExprSpan(pNew, &pLeft->span, &pRight->span);
+ }
+ return pNew;
+}
+
+/*
+** Join two expressions using an AND operator. If either expression is
+** NULL, then just return the other expression.
+*/
+Expr *sqlite3ExprAnd(Expr *pLeft, Expr *pRight){
+ if( pLeft==0 ){
+ return pRight;
+ }else if( pRight==0 ){
+ return pLeft;
+ }else{
+ return sqlite3Expr(TK_AND, pLeft, pRight, 0);
+ }
+}
+
+/*
+** Set the Expr.span field of the given expression to span all
+** text between the two given tokens.
+*/
+void sqlite3ExprSpan(Expr *pExpr, Token *pLeft, Token *pRight){
+ assert( pRight!=0 );
+ assert( pLeft!=0 );
+ if( !sqlite3_malloc_failed && pRight->z && pLeft->z ){
+ assert( pLeft->dyn==0 || pLeft->z[pLeft->n]==0 );
+ if( pLeft->dyn==0 && pRight->dyn==0 ){
+ pExpr->span.z = pLeft->z;
+ pExpr->span.n = pRight->n + Addr(pRight->z) - Addr(pLeft->z);
+ }else{
+ pExpr->span.z = 0;
+ }
+ }
+}
+
+/*
+** Construct a new expression node for a function with multiple
+** arguments.
+*/
+Expr *sqlite3ExprFunction(ExprList *pList, Token *pToken){
+ Expr *pNew;
+ pNew = sqliteMalloc( sizeof(Expr) );
+ if( pNew==0 ){
+ /* sqlite3ExprListDelete(pList); // Leak pList when malloc fails */
+ return 0;
+ }
+ pNew->op = TK_FUNCTION;
+ pNew->pList = pList;
+ if( pToken ){
+ assert( pToken->dyn==0 );
+ pNew->token = *pToken;
+ }else{
+ pNew->token.z = 0;
+ }
+ pNew->span = pNew->token;
+ return pNew;
+}
+
+/*
+** Assign a variable number to an expression that encodes a wildcard
+** in the original SQL statement.
+**
+** Wildcards consisting of a single "?" are assigned the next sequential
+** variable number.
+**
+** Wildcards of the form "?nnn" are assigned the number "nnn". We make
+** sure "nnn" is not too be to avoid a denial of service attack when
+** the SQL statement comes from an external source.
+**
+** Wildcards of the form ":aaa" or "$aaa" are assigned the same number
+** as the previous instance of the same wildcard. Or if this is the first
+** instance of the wildcard, the next sequenial variable number is
+** assigned.
+*/
+void sqlite3ExprAssignVarNumber(Parse *pParse, Expr *pExpr){
+ Token *pToken;
+ if( pExpr==0 ) return;
+ pToken = &pExpr->token;
+ assert( pToken->n>=1 );
+ assert( pToken->z!=0 );
+ assert( pToken->z[0]!=0 );
+ if( pToken->n==1 ){
+ /* Wildcard of the form "?". Assign the next variable number */
+ pExpr->iTable = ++pParse->nVar;
+ }else if( pToken->z[0]=='?' ){
+ /* Wildcard of the form "?nnn". Convert "nnn" to an integer and
+ ** use it as the variable number */
+ int i;
+ pExpr->iTable = i = atoi(&pToken->z[1]);
+ if( i<1 || i>SQLITE_MAX_VARIABLE_NUMBER ){
+ sqlite3ErrorMsg(pParse, "variable number must be between ?1 and ?%d",
+ SQLITE_MAX_VARIABLE_NUMBER);
+ }
+ if( i>pParse->nVar ){
+ pParse->nVar = i;
+ }
+ }else{
+ /* Wildcards of the form ":aaa" or "$aaa". Reuse the same variable
+ ** number as the prior appearance of the same name, or if the name
+ ** has never appeared before, reuse the same variable number
+ */
+ int i, n;
+ n = pToken->n;
+ for(i=0; i<pParse->nVarExpr; i++){
+ Expr *pE;
+ if( (pE = pParse->apVarExpr[i])!=0
+ && pE->token.n==n
+ && memcmp(pE->token.z, pToken->z, n)==0 ){
+ pExpr->iTable = pE->iTable;
+ break;
+ }
+ }
+ if( i>=pParse->nVarExpr ){
+ pExpr->iTable = ++pParse->nVar;
+ if( pParse->nVarExpr>=pParse->nVarExprAlloc-1 ){
+ pParse->nVarExprAlloc += pParse->nVarExprAlloc + 10;
+ pParse->apVarExpr = sqliteRealloc(pParse->apVarExpr,
+ pParse->nVarExprAlloc*sizeof(pParse->apVarExpr[0]) );
+ }
+ if( !sqlite3_malloc_failed ){
+ assert( pParse->apVarExpr!=0 );
+ pParse->apVarExpr[pParse->nVarExpr++] = pExpr;
+ }
+ }
+ }
+}
+
+/*
+** Recursively delete an expression tree.
+*/
+void sqlite3ExprDelete(Expr *p){
+ if( p==0 ) return;
+ if( p->span.dyn ) sqliteFree((char*)p->span.z);
+ if( p->token.dyn ) sqliteFree((char*)p->token.z);
+ sqlite3ExprDelete(p->pLeft);
+ sqlite3ExprDelete(p->pRight);
+ sqlite3ExprListDelete(p->pList);
+ sqlite3SelectDelete(p->pSelect);
+ sqliteFree(p);
+}
+
+
+/*
+** 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.
+**
+** The expression list, ID, and source lists return by sqlite3ExprListDup(),
+** sqlite3IdListDup(), and sqlite3SrcListDup() can not be further expanded
+** by subsequent calls to sqlite*ListAppend() routines.
+**
+** Any tables that the SrcList might point to are not duplicated.
+*/
+Expr *sqlite3ExprDup(Expr *p){
+ Expr *pNew;
+ if( p==0 ) return 0;
+ pNew = sqliteMallocRaw( sizeof(*p) );
+ if( pNew==0 ) return 0;
+ memcpy(pNew, p, sizeof(*pNew));
+ if( p->token.z!=0 ){
+ pNew->token.z = sqliteStrDup(p->token.z);
+ pNew->token.dyn = 1;
+ }else{
+ assert( pNew->token.z==0 );
+ }
+ pNew->span.z = 0;
+ pNew->pLeft = sqlite3ExprDup(p->pLeft);
+ pNew->pRight = sqlite3ExprDup(p->pRight);
+ pNew->pList = sqlite3ExprListDup(p->pList);
+ pNew->pSelect = sqlite3SelectDup(p->pSelect);
+ return pNew;
+}
+void sqlite3TokenCopy(Token *pTo, Token *pFrom){
+ if( pTo->dyn ) sqliteFree((char*)pTo->z);
+ if( pFrom->z ){
+ pTo->n = pFrom->n;
+ pTo->z = sqliteStrNDup(pFrom->z, pFrom->n);
+ pTo->dyn = 1;
+ }else{
+ pTo->z = 0;
+ }
+}
+ExprList *sqlite3ExprListDup(ExprList *p){
+ ExprList *pNew;
+ struct ExprList_item *pItem, *pOldItem;
+ int i;
+ if( p==0 ) return 0;
+ pNew = sqliteMalloc( sizeof(*pNew) );
+ if( pNew==0 ) return 0;
+ pNew->nExpr = pNew->nAlloc = p->nExpr;
+ pNew->a = pItem = sqliteMalloc( p->nExpr*sizeof(p->a[0]) );
+ if( pItem==0 ){
+ sqliteFree(pNew);
+ return 0;
+ }
+ pOldItem = p->a;
+ for(i=0; i<p->nExpr; i++, pItem++, pOldItem++){
+ Expr *pNewExpr, *pOldExpr;
+ pItem->pExpr = pNewExpr = sqlite3ExprDup(pOldExpr = pOldItem->pExpr);
+ if( pOldExpr->span.z!=0 && pNewExpr ){
+ /* Always make a copy of the span for top-level expressions in the
+ ** expression list. The logic in SELECT processing that determines
+ ** the names of columns in the result set needs this information */
+ sqlite3TokenCopy(&pNewExpr->span, &pOldExpr->span);
+ }
+ assert( pNewExpr==0 || pNewExpr->span.z!=0
+ || pOldExpr->span.z==0 || sqlite3_malloc_failed );
+ pItem->zName = sqliteStrDup(pOldItem->zName);
+ pItem->sortOrder = pOldItem->sortOrder;
+ pItem->isAgg = pOldItem->isAgg;
+ pItem->done = 0;
+ }
+ return pNew;
+}
+SrcList *sqlite3SrcListDup(SrcList *p){
+ SrcList *pNew;
+ int i;
+ int nByte;
+ if( p==0 ) return 0;
+ nByte = sizeof(*p) + (p->nSrc>0 ? sizeof(p->a[0]) * (p->nSrc-1) : 0);
+ pNew = sqliteMallocRaw( nByte );
+ if( pNew==0 ) return 0;
+ pNew->nSrc = pNew->nAlloc = p->nSrc;
+ for(i=0; i<p->nSrc; i++){
+ struct SrcList_item *pNewItem = &pNew->a[i];
+ struct SrcList_item *pOldItem = &p->a[i];
+ pNewItem->zDatabase = sqliteStrDup(pOldItem->zDatabase);
+ pNewItem->zName = sqliteStrDup(pOldItem->zName);
+ pNewItem->zAlias = sqliteStrDup(pOldItem->zAlias);
+ pNewItem->jointype = pOldItem->jointype;
+ pNewItem->iCursor = pOldItem->iCursor;
+ pNewItem->pTab = 0;
+ pNewItem->pSelect = sqlite3SelectDup(pOldItem->pSelect);
+ pNewItem->pOn = sqlite3ExprDup(pOldItem->pOn);
+ pNewItem->pUsing = sqlite3IdListDup(pOldItem->pUsing);
+ }
+ return pNew;
+}
+IdList *sqlite3IdListDup(IdList *p){
+ IdList *pNew;
+ int i;
+ if( p==0 ) return 0;
+ pNew = sqliteMallocRaw( sizeof(*pNew) );
+ if( pNew==0 ) return 0;
+ pNew->nId = pNew->nAlloc = p->nId;
+ pNew->a = sqliteMallocRaw( p->nId*sizeof(p->a[0]) );
+ if( pNew->a==0 ) return 0;
+ for(i=0; i<p->nId; i++){
+ struct IdList_item *pNewItem = &pNew->a[i];
+ struct IdList_item *pOldItem = &p->a[i];
+ pNewItem->zName = sqliteStrDup(pOldItem->zName);
+ pNewItem->idx = pOldItem->idx;
+ }
+ return pNew;
+}
+Select *sqlite3SelectDup(Select *p){
+ Select *pNew;
+ if( p==0 ) return 0;
+ pNew = sqliteMallocRaw( sizeof(*p) );
+ if( pNew==0 ) return 0;
+ pNew->isDistinct = p->isDistinct;
+ pNew->pEList = sqlite3ExprListDup(p->pEList);
+ pNew->pSrc = sqlite3SrcListDup(p->pSrc);
+ pNew->pWhere = sqlite3ExprDup(p->pWhere);
+ pNew->pGroupBy = sqlite3ExprListDup(p->pGroupBy);
+ pNew->pHaving = sqlite3ExprDup(p->pHaving);
+ pNew->pOrderBy = sqlite3ExprListDup(p->pOrderBy);
+ pNew->op = p->op;
+ pNew->pPrior = sqlite3SelectDup(p->pPrior);
+ pNew->nLimit = p->nLimit;
+ pNew->nOffset = p->nOffset;
+ pNew->zSelect = 0;
+ pNew->iLimit = -1;
+ pNew->iOffset = -1;
+ pNew->ppOpenTemp = 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 *sqlite3ExprListAppend(ExprList *pList, Expr *pExpr, Token *pName){
+ if( pList==0 ){
+ pList = sqliteMalloc( sizeof(ExprList) );
+ if( pList==0 ){
+ /* sqlite3ExprDelete(pExpr); // Leak memory if malloc fails */
+ return 0;
+ }
+ assert( pList->nAlloc==0 );
+ }
+ if( pList->nAlloc<=pList->nExpr ){
+ pList->nAlloc = pList->nAlloc*2 + 4;
+ pList->a = sqliteRealloc(pList->a, pList->nAlloc*sizeof(pList->a[0]));
+ if( pList->a==0 ){
+ /* sqlite3ExprDelete(pExpr); // Leak memory if malloc fails */
+ pList->nExpr = pList->nAlloc = 0;
+ return pList;
+ }
+ }
+ assert( pList->a!=0 );
+ if( pExpr || pName ){
+ struct ExprList_item *pItem = &pList->a[pList->nExpr++];
+ memset(pItem, 0, sizeof(*pItem));
+ pItem->pExpr = pExpr;
+ pItem->zName = sqlite3NameFromToken(pName);
+ }
+ return pList;
+}
+
+/*
+** Delete an entire expression list.
+*/
+void sqlite3ExprListDelete(ExprList *pList){
+ int i;
+ struct ExprList_item *pItem;
+ if( pList==0 ) return;
+ assert( pList->a!=0 || (pList->nExpr==0 && pList->nAlloc==0) );
+ assert( pList->nExpr<=pList->nAlloc );
+ for(pItem=pList->a, i=0; i<pList->nExpr; i++, pItem++){
+ sqlite3ExprDelete(pItem->pExpr);
+ sqliteFree(pItem->zName);
+ }
+ sqliteFree(pList->a);
+ sqliteFree(pList);
+}
+
+/*
+** Walk an expression tree. Return 1 if the expression is constant
+** and 0 if it involves variables.
+**
+** For the purposes of this function, a double-quoted string (ex: "abc")
+** is considered a variable but a single-quoted string (ex: 'abc') is
+** a constant.
+*/
+int sqlite3ExprIsConstant(Expr *p){
+ switch( p->op ){
+ case TK_ID:
+ case TK_COLUMN:
+ case TK_DOT:
+ case TK_FUNCTION:
+ return 0;
+ case TK_NULL:
+ case TK_STRING:
+ case TK_BLOB:
+ case TK_INTEGER:
+ case TK_FLOAT:
+ case TK_VARIABLE:
+ return 1;
+ default: {
+ if( p->pLeft && !sqlite3ExprIsConstant(p->pLeft) ) return 0;
+ if( p->pRight && !sqlite3ExprIsConstant(p->pRight) ) return 0;
+ if( p->pList ){
+ int i;
+ for(i=0; i<p->pList->nExpr; i++){
+ if( !sqlite3ExprIsConstant(p->pList->a[i].pExpr) ) return 0;
+ }
+ }
+ return p->pLeft!=0 || p->pRight!=0 || (p->pList && p->pList->nExpr>0);
+ }
+ }
+ return 0;
+}
+
+/*
+** If the given expression codes a constant integer that is small enough
+** to fit in a 32-bit integer, return 1 and put the value of the integer
+** in *pValue. If the expression is not an integer or if it is too big
+** to fit in a signed 32-bit integer, return 0 and leave *pValue unchanged.
+*/
+int sqlite3ExprIsInteger(Expr *p, int *pValue){
+ switch( p->op ){
+ case TK_INTEGER: {
+ if( sqlite3GetInt32(p->token.z, pValue) ){
+ return 1;
+ }
+ break;
+ }
+ case TK_STRING: {
+ const u8 *z = (u8*)p->token.z;
+ int n = p->token.n;
+ if( n>0 && z[0]=='-' ){ z++; n--; }
+ while( n>0 && *z && isdigit(*z) ){ z++; n--; }
+ if( n==0 && sqlite3GetInt32(p->token.z, pValue) ){
+ return 1;
+ }
+ break;
+ }
+ case TK_UPLUS: {
+ return sqlite3ExprIsInteger(p->pLeft, pValue);
+ }
+ case TK_UMINUS: {
+ int v;
+ if( sqlite3ExprIsInteger(p->pLeft, &v) ){
+ *pValue = -v;
+ return 1;
+ }
+ break;
+ }
+ default: break;
+ }
+ return 0;
+}
+
+/*
+** Return TRUE if the given string is a row-id column name.
+*/
+int sqlite3IsRowid(const char *z){
+ if( sqlite3StrICmp(z, "_ROWID_")==0 ) return 1;
+ if( sqlite3StrICmp(z, "ROWID")==0 ) return 1;
+ if( sqlite3StrICmp(z, "OID")==0 ) return 1;
+ return 0;
+}
+
+/*
+** Given the name of a column of the form X.Y.Z or Y.Z or just Z, look up
+** that name in the set of source tables in pSrcList and make the pExpr
+** expression node refer back to that source column. The following changes
+** are made to pExpr:
+**
+** pExpr->iDb Set the index in db->aDb[] of the database holding
+** the table.
+** pExpr->iTable Set to the cursor number for the table obtained
+** from pSrcList.
+** pExpr->iColumn Set to the column number within the table.
+** pExpr->op Set to TK_COLUMN.
+** pExpr->pLeft Any expression this points to is deleted
+** pExpr->pRight Any expression this points to is deleted.
+**
+** The pDbToken is the name of the database (the "X"). This value may be
+** NULL meaning that name is of the form Y.Z or Z. Any available database
+** can be used. The pTableToken is the name of the table (the "Y"). This
+** value can be NULL if pDbToken is also NULL. If pTableToken is NULL it
+** means that the form of the name is Z and that columns from any table
+** can be used.
+**
+** If the name cannot be resolved unambiguously, leave an error message
+** in pParse and return non-zero. Return zero on success.
+*/
+static int lookupName(
+ Parse *pParse, /* The parsing context */
+ Token *pDbToken, /* Name of the database containing table, or NULL */
+ Token *pTableToken, /* Name of table containing column, or NULL */
+ Token *pColumnToken, /* Name of the column. */
+ SrcList *pSrcList, /* List of tables used to resolve column names */
+ ExprList *pEList, /* List of expressions used to resolve "AS" */
+ Expr *pExpr /* Make this EXPR node point to the selected column */
+){
+ char *zDb = 0; /* Name of the database. The "X" in X.Y.Z */
+ char *zTab = 0; /* Name of the table. The "Y" in X.Y.Z or Y.Z */
+ char *zCol = 0; /* Name of the column. The "Z" */
+ int i, j; /* Loop counters */
+ int cnt = 0; /* Number of matching column names */
+ int cntTab = 0; /* Number of matching table names */
+ sqlite3 *db = pParse->db; /* The database */
+
+ assert( pColumnToken && pColumnToken->z ); /* The Z in X.Y.Z cannot be NULL */
+ zDb = sqlite3NameFromToken(pDbToken);
+ zTab = sqlite3NameFromToken(pTableToken);
+ zCol = sqlite3NameFromToken(pColumnToken);
+ if( sqlite3_malloc_failed ){
+ return 1; /* Leak memory (zDb and zTab) if malloc fails */
+ }
+ assert( zTab==0 || pEList==0 );
+
+ pExpr->iTable = -1;
+ for(i=0; i<pSrcList->nSrc; i++){
+ struct SrcList_item *pItem = &pSrcList->a[i];
+ Table *pTab = pItem->pTab;
+ Column *pCol;
+
+ if( pTab==0 ) continue;
+ assert( pTab->nCol>0 );
+ if( zTab ){
+ if( pItem->zAlias ){
+ char *zTabName = pItem->zAlias;
+ if( sqlite3StrICmp(zTabName, zTab)!=0 ) continue;
+ }else{
+ char *zTabName = pTab->zName;
+ if( zTabName==0 || sqlite3StrICmp(zTabName, zTab)!=0 ) continue;
+ if( zDb!=0 && sqlite3StrICmp(db->aDb[pTab->iDb].zName, zDb)!=0 ){
+ continue;
+ }
+ }
+ }
+ if( 0==(cntTab++) ){
+ pExpr->iTable = pItem->iCursor;
+ pExpr->iDb = pTab->iDb;
+ }
+ for(j=0, pCol=pTab->aCol; j<pTab->nCol; j++, pCol++){
+ if( sqlite3StrICmp(pCol->zName, zCol)==0 ){
+ cnt++;
+ pExpr->iTable = pItem->iCursor;
+ pExpr->iDb = pTab->iDb;
+ /* Substitute the rowid (column -1) for the INTEGER PRIMARY KEY */
+ pExpr->iColumn = j==pTab->iPKey ? -1 : j;
+ pExpr->affinity = pTab->aCol[j].affinity;
+ pExpr->pColl = pTab->aCol[j].pColl;
+ break;
+ }
+ }
+ }
+
+ /* If we have not already resolved the name, then maybe
+ ** it is a new.* or old.* trigger argument reference
+ */
+ if( zDb==0 && zTab!=0 && cnt==0 && pParse->trigStack!=0 ){
+ TriggerStack *pTriggerStack = pParse->trigStack;
+ Table *pTab = 0;
+ if( pTriggerStack->newIdx != -1 && sqlite3StrICmp("new", zTab) == 0 ){
+ pExpr->iTable = pTriggerStack->newIdx;
+ assert( pTriggerStack->pTab );
+ pTab = pTriggerStack->pTab;
+ }else if( pTriggerStack->oldIdx != -1 && sqlite3StrICmp("old", zTab) == 0 ){
+ pExpr->iTable = pTriggerStack->oldIdx;
+ assert( pTriggerStack->pTab );
+ pTab = pTriggerStack->pTab;
+ }
+
+ if( pTab ){
+ int j;
+ Column *pCol = pTab->aCol;
+
+ pExpr->iDb = pTab->iDb;
+ cntTab++;
+ for(j=0; j < pTab->nCol; j++, pCol++) {
+ if( sqlite3StrICmp(pCol->zName, zCol)==0 ){
+ cnt++;
+ pExpr->iColumn = j==pTab->iPKey ? -1 : j;
+ pExpr->affinity = pTab->aCol[j].affinity;
+ pExpr->pColl = pTab->aCol[j].pColl;
+ break;
+ }
+ }
+ }
+ }
+
+ /*
+ ** Perhaps the name is a reference to the ROWID
+ */
+ if( cnt==0 && cntTab==1 && sqlite3IsRowid(zCol) ){
+ cnt = 1;
+ pExpr->iColumn = -1;
+ pExpr->affinity = SQLITE_AFF_INTEGER;
+ }
+
+ /*
+ ** If the input is of the form Z (not Y.Z or X.Y.Z) then the name Z
+ ** might refer to an result-set alias. This happens, for example, when
+ ** we are resolving names in the WHERE clause of the following command:
+ **
+ ** SELECT a+b AS x FROM table WHERE x<10;
+ **
+ ** In cases like this, replace pExpr with a copy of the expression that
+ ** forms the result set entry ("a+b" in the example) and return immediately.
+ ** Note that the expression in the result set should have already been
+ ** resolved by the time the WHERE clause is resolved.
+ */
+ if( cnt==0 && pEList!=0 ){
+ for(j=0; j<pEList->nExpr; j++){
+ char *zAs = pEList->a[j].zName;
+ if( zAs!=0 && sqlite3StrICmp(zAs, zCol)==0 ){
+ assert( pExpr->pLeft==0 && pExpr->pRight==0 );
+ pExpr->op = TK_AS;
+ pExpr->iColumn = j;
+ pExpr->pLeft = sqlite3ExprDup(pEList->a[j].pExpr);
+ sqliteFree(zCol);
+ assert( zTab==0 && zDb==0 );
+ return 0;
+ }
+ }
+ }
+
+ /*
+ ** If X and Y are NULL (in other words if only the column name Z is
+ ** supplied) and the value of Z is enclosed in double-quotes, then
+ ** Z is a string literal if it doesn't match any column names. In that
+ ** case, we need to return right away and not make any changes to
+ ** pExpr.
+ */
+ if( cnt==0 && zTab==0 && pColumnToken->z[0]=='"' ){
+ sqliteFree(zCol);
+ return 0;
+ }
+
+ /*
+ ** cnt==0 means there was not match. cnt>1 means there were two or
+ ** more matches. Either way, we have an error.
+ */
+ if( cnt!=1 ){
+ char *z = 0;
+ char *zErr;
+ zErr = cnt==0 ? "no such column: %s" : "ambiguous column name: %s";
+ if( zDb ){
+ sqlite3SetString(&z, zDb, ".", zTab, ".", zCol, 0);
+ }else if( zTab ){
+ sqlite3SetString(&z, zTab, ".", zCol, 0);
+ }else{
+ z = sqliteStrDup(zCol);
+ }
+ sqlite3ErrorMsg(pParse, zErr, z);
+ sqliteFree(z);
+ }
+
+ /* Clean up and return
+ */
+ sqliteFree(zDb);
+ sqliteFree(zTab);
+ sqliteFree(zCol);
+ sqlite3ExprDelete(pExpr->pLeft);
+ pExpr->pLeft = 0;
+ sqlite3ExprDelete(pExpr->pRight);
+ pExpr->pRight = 0;
+ pExpr->op = TK_COLUMN;
+ sqlite3AuthRead(pParse, pExpr, pSrcList);
+ return cnt!=1;
+}
+
+/*
+** 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 "base" value. The base 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 sqlite3ExprResolveIds(
+ Parse *pParse, /* The parser context */
+ SrcList *pSrcList, /* List of tables used to resolve column names */
+ ExprList *pEList, /* List of expressions used to resolve "AS" */
+ Expr *pExpr /* The expression to be analyzed. */
+){
+ int i;
+
+ if( pExpr==0 || pSrcList==0 ) return 0;
+ for(i=0; i<pSrcList->nSrc; i++){
+ assert( pSrcList->a[i].iCursor>=0 && pSrcList->a[i].iCursor<pParse->nTab );
+ }
+ switch( pExpr->op ){
+ /* Double-quoted strings (ex: "abc") are used as identifiers if
+ ** possible. Otherwise they remain as strings. Single-quoted
+ ** strings (ex: 'abc') are always string literals.
+ */
+ case TK_STRING: {
+ if( pExpr->token.z[0]=='\'' ) break;
+ /* Fall thru into the TK_ID case if this is a double-quoted string */
+ }
+ /* A lone identifier is the name of a columnd.
+ */
+ case TK_ID: {
+ if( lookupName(pParse, 0, 0, &pExpr->token, pSrcList, pEList, pExpr) ){
+ return 1;
+ }
+ break;
+ }
+
+ /* A table name and column name: ID.ID
+ ** Or a database, table and column: ID.ID.ID
+ */
+ case TK_DOT: {
+ Token *pColumn;
+ Token *pTable;
+ Token *pDb;
+ Expr *pRight;
+
+ pRight = pExpr->pRight;
+ if( pRight->op==TK_ID ){
+ pDb = 0;
+ pTable = &pExpr->pLeft->token;
+ pColumn = &pRight->token;
+ }else{
+ assert( pRight->op==TK_DOT );
+ pDb = &pExpr->pLeft->token;
+ pTable = &pRight->pLeft->token;
+ pColumn = &pRight->pRight->token;
+ }
+ if( lookupName(pParse, pDb, pTable, pColumn, pSrcList, 0, pExpr) ){
+ return 1;
+ }
+ break;
+ }
+
+ case TK_IN: {
+ char affinity;
+ Vdbe *v = sqlite3GetVdbe(pParse);
+ KeyInfo keyInfo;
+ int addr; /* Address of OP_OpenTemp instruction */
+
+ if( v==0 ) return 1;
+ if( sqlite3ExprResolveIds(pParse, pSrcList, pEList, pExpr->pLeft) ){
+ return 1;
+ }
+ affinity = sqlite3ExprAffinity(pExpr->pLeft);
+
+ /* Whether this is an 'x IN(SELECT...)' or an 'x IN(<exprlist>)'
+ ** expression it is handled the same way. A temporary table is
+ ** filled with single-field index keys representing the results
+ ** from the SELECT or the <exprlist>.
+ **
+ ** If the 'x' expression is a column value, or the SELECT...
+ ** statement returns a column value, then the affinity of that
+ ** column is used to build the index keys. If both 'x' and the
+ ** SELECT... statement are columns, then numeric affinity is used
+ ** if either column has NUMERIC or INTEGER affinity. If neither
+ ** 'x' nor the SELECT... statement are columns, then numeric affinity
+ ** is used.
+ */
+ pExpr->iTable = pParse->nTab++;
+ addr = sqlite3VdbeAddOp(v, OP_OpenTemp, pExpr->iTable, 0);
+ memset(&keyInfo, 0, sizeof(keyInfo));
+ keyInfo.nField = 1;
+ sqlite3VdbeAddOp(v, OP_SetNumColumns, pExpr->iTable, 1);
+
+ if( pExpr->pSelect ){
+ /* Case 1: expr IN (SELECT ...)
+ **
+ ** Generate code to write the results of the select into the temporary
+ ** table allocated and opened above.
+ */
+ int iParm = pExpr->iTable + (((int)affinity)<<16);
+ ExprList *pEList;
+ assert( (pExpr->iTable&0x0000FFFF)==pExpr->iTable );
+ sqlite3Select(pParse, pExpr->pSelect, SRT_Set, iParm, 0, 0, 0, 0);
+ pEList = pExpr->pSelect->pEList;
+ if( pEList && pEList->nExpr>0 ){
+ keyInfo.aColl[0] = binaryCompareCollSeq(pParse, pExpr->pLeft,
+ pEList->a[0].pExpr);
+ }
+ }else if( pExpr->pList ){
+ /* Case 2: expr IN (exprlist)
+ **
+ ** For each expression, build an index key from the evaluation and
+ ** store it in the temporary table. If <expr> is a column, then use
+ ** that columns affinity when building index keys. If <expr> is not
+ ** a column, use numeric affinity.
+ */
+ int i;
+ if( !affinity ){
+ affinity = SQLITE_AFF_NUMERIC;
+ }
+ keyInfo.aColl[0] = pExpr->pLeft->pColl;
+
+ /* Loop through each expression in <exprlist>. */
+ for(i=0; i<pExpr->pList->nExpr; i++){
+ Expr *pE2 = pExpr->pList->a[i].pExpr;
+
+ /* Check that the expression is constant and valid. */
+ if( !sqlite3ExprIsConstant(pE2) ){
+ sqlite3ErrorMsg(pParse,
+ "right-hand side of IN operator must be constant");
+ return 1;
+ }
+ if( sqlite3ExprCheck(pParse, pE2, 0, 0) ){
+ return 1;
+ }
+
+ /* Evaluate the expression and insert it into the temp table */
+ sqlite3ExprCode(pParse, pE2);
+ sqlite3VdbeOp3(v, OP_MakeRecord, 1, 0, &affinity, 1);
+ sqlite3VdbeAddOp(v, OP_String8, 0, 0);
+ sqlite3VdbeAddOp(v, OP_PutStrKey, pExpr->iTable, 0);
+ }
+ }
+ sqlite3VdbeChangeP3(v, addr, (void *)&keyInfo, P3_KEYINFO);
+
+ 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(sqlite3Select(pParse, pExpr->pSelect, SRT_Mem,pExpr->iColumn,0,0,0,0)){
+ return 1;
+ }
+ break;
+ }
+
+ /* For all else, just recursively walk the tree */
+ default: {
+ if( pExpr->pLeft
+ && sqlite3ExprResolveIds(pParse, pSrcList, pEList, pExpr->pLeft) ){
+ return 1;
+ }
+ if( pExpr->pRight
+ && sqlite3ExprResolveIds(pParse, pSrcList, pEList, pExpr->pRight) ){
+ return 1;
+ }
+ if( pExpr->pList ){
+ int i;
+ ExprList *pList = pExpr->pList;
+ for(i=0; i<pList->nExpr; i++){
+ Expr *pArg = pList->a[i].pExpr;
+ if( sqlite3ExprResolveIds(pParse, pSrcList, pEList, pArg) ){
+ return 1;
+ }
+ }
+ }
+ }
+ }
+ return 0;
+}
+
+/*
+** pExpr is a node that defines a function of some kind. It might
+** be a syntactic function like "count(x)" or it might be a function
+** that implements an operator, like "a LIKE b".
+**
+** This routine makes *pzName point to the name of the function and
+** *pnName hold the number of characters in the function name.
+*/
+static void getFunctionName(Expr *pExpr, const char **pzName, int *pnName){
+ switch( pExpr->op ){
+ case TK_FUNCTION: {
+ *pzName = pExpr->token.z;
+ *pnName = pExpr->token.n;
+ break;
+ }
+ case TK_LIKE: {
+ *pzName = "like";
+ *pnName = 4;
+ break;
+ }
+ case TK_GLOB: {
+ *pzName = "glob";
+ *pnName = 4;
+ break;
+ }
+ default: {
+ *pzName = "can't happen";
+ *pnName = 12;
+ break;
+ }
+ }
+}
+
+/*
+** 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 sqlite3ExprCheck(Parse *pParse, Expr *pExpr, int allowAgg, int *pIsAgg){
+ int nErr = 0;
+ if( pExpr==0 ) return 0;
+ switch( pExpr->op ){
+ case TK_GLOB:
+ case TK_LIKE:
+ case TK_FUNCTION: {
+ int n = pExpr->pList ? pExpr->pList->nExpr : 0; /* Number of arguments */
+ int no_such_func = 0; /* True if no such function exists */
+ int wrong_num_args = 0; /* True if wrong number of arguments */
+ int is_agg = 0; /* True if is an aggregate function */
+ int i;
+ int nId; /* Number of characters in function name */
+ const char *zId; /* The function name. */
+ FuncDef *pDef;
+ int enc = pParse->db->enc;
+
+ getFunctionName(pExpr, &zId, &nId);
+ pDef = sqlite3FindFunction(pParse->db, zId, nId, n, enc, 0);
+ if( pDef==0 ){
+ pDef = sqlite3FindFunction(pParse->db, zId, nId, -1, enc, 0);
+ if( pDef==0 ){
+ no_such_func = 1;
+ }else{
+ wrong_num_args = 1;
+ }
+ }else{
+ is_agg = pDef->xFunc==0;
+ }
+ if( is_agg && !allowAgg ){
+ sqlite3ErrorMsg(pParse, "misuse of aggregate function %.*s()", nId, zId);
+ nErr++;
+ is_agg = 0;
+ }else if( no_such_func ){
+ sqlite3ErrorMsg(pParse, "no such function: %.*s", nId, zId);
+ nErr++;
+ }else if( wrong_num_args ){
+ sqlite3ErrorMsg(pParse,"wrong number of arguments to function %.*s()",
+ nId, zId);
+ nErr++;
+ }
+ if( is_agg ){
+ pExpr->op = TK_AGG_FUNCTION;
+ if( pIsAgg ) *pIsAgg = 1;
+ }
+ for(i=0; nErr==0 && i<n; i++){
+ nErr = sqlite3ExprCheck(pParse, pExpr->pList->a[i].pExpr,
+ allowAgg && !is_agg, pIsAgg);
+ }
+ /* FIX ME: Compute pExpr->affinity based on the expected return
+ ** type of the function
+ */
+ }
+ default: {
+ if( pExpr->pLeft ){
+ nErr = sqlite3ExprCheck(pParse, pExpr->pLeft, allowAgg, pIsAgg);
+ }
+ if( nErr==0 && pExpr->pRight ){
+ nErr = sqlite3ExprCheck(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 = sqlite3ExprCheck(pParse, pE2, allowAgg, pIsAgg);
+ }
+ }
+ break;
+ }
+ }
+ return nErr;
+}
+
+/*
+** Call sqlite3ExprResolveIds() followed by sqlite3ExprCheck().
+**
+** This routine is provided as a convenience since it is very common
+** to call ResolveIds() and Check() back to back.
+*/
+int sqlite3ExprResolveAndCheck(
+ Parse *pParse, /* The parser context */
+ SrcList *pSrcList, /* List of tables used to resolve column names */
+ ExprList *pEList, /* List of expressions used to resolve "AS" */
+ Expr *pExpr, /* The expression to be analyzed. */
+ int allowAgg, /* True to allow aggregate expressions */
+ int *pIsAgg /* Set to TRUE if aggregates are found */
+){
+ if( pExpr==0 ) return 0;
+ if( sqlite3ExprResolveIds(pParse,pSrcList,pEList,pExpr) ){
+ return 1;
+ }
+ return sqlite3ExprCheck(pParse, pExpr, allowAgg, pIsAgg);
+}
+
+/*
+** Generate an instruction that will put the integer describe by
+** text z[0..n-1] on the stack.
+*/
+static void codeInteger(Vdbe *v, const char *z, int n){
+ int i;
+ if( sqlite3GetInt32(z, &i) ){
+ sqlite3VdbeAddOp(v, OP_Integer, i, 0);
+ }else if( sqlite3FitsIn64Bits(z) ){
+ sqlite3VdbeOp3(v, OP_Integer, 0, 0, z, n);
+ }else{
+ sqlite3VdbeOp3(v, OP_Real, 0, 0, z, n);
+ }
+}
+
+/*
+** Generate code into the current Vdbe to evaluate the given
+** expression and leave the result on the top of stack.
+**
+** This code depends on the fact that certain token values (ex: TK_EQ)
+** are the same as opcode values (ex: OP_Eq) that implement the corresponding
+** operation. Special comments in vdbe.c and the mkopcodeh.awk script in
+** the make process cause these values to align. Assert()s in the code
+** below verify that the numbers are aligned correctly.
+*/
+void sqlite3ExprCode(Parse *pParse, Expr *pExpr){
+ Vdbe *v = pParse->pVdbe;
+ int op;
+ if( v==0 || pExpr==0 ) return;
+ op = pExpr->op;
+ switch( op ){
+ case TK_COLUMN: {
+ if( pParse->useAgg ){
+ sqlite3VdbeAddOp(v, OP_AggGet, 0, pExpr->iAgg);
+ }else if( pExpr->iColumn>=0 ){
+ sqlite3VdbeAddOp(v, OP_Column, pExpr->iTable, pExpr->iColumn);
+#ifndef NDEBUG
+ if( pExpr->span.z && pExpr->span.n>0 && pExpr->span.n<100 ){
+ VdbeComment((v, "# %T", &pExpr->span));
+ }
+#endif
+ }else{
+ sqlite3VdbeAddOp(v, OP_Recno, pExpr->iTable, 0);
+ }
+ break;
+ }
+ case TK_INTEGER: {
+ codeInteger(v, pExpr->token.z, pExpr->token.n);
+ break;
+ }
+ case TK_FLOAT:
+ case TK_STRING: {
+ assert( TK_FLOAT==OP_Real );
+ assert( TK_STRING==OP_String8 );
+ sqlite3VdbeOp3(v, op, 0, 0, pExpr->token.z, pExpr->token.n);
+ sqlite3VdbeDequoteP3(v, -1);
+ break;
+ }
+ case TK_BLOB: {
+ assert( TK_BLOB==OP_HexBlob );
+ sqlite3VdbeOp3(v, op, 0, 0, pExpr->token.z+1, pExpr->token.n-1);
+ sqlite3VdbeDequoteP3(v, -1);
+ break;
+ }
+ case TK_NULL: {
+ sqlite3VdbeAddOp(v, OP_String8, 0, 0);
+ break;
+ }
+ case TK_VARIABLE: {
+ sqlite3VdbeAddOp(v, OP_Variable, pExpr->iTable, 0);
+ if( pExpr->token.n>1 ){
+ sqlite3VdbeChangeP3(v, -1, pExpr->token.z, pExpr->token.n);
+ }
+ break;
+ }
+ case TK_LT:
+ case TK_LE:
+ case TK_GT:
+ case TK_GE:
+ case TK_NE:
+ case TK_EQ: {
+ assert( TK_LT==OP_Lt );
+ assert( TK_LE==OP_Le );
+ assert( TK_GT==OP_Gt );
+ assert( TK_GE==OP_Ge );
+ assert( TK_EQ==OP_Eq );
+ assert( TK_NE==OP_Ne );
+ sqlite3ExprCode(pParse, pExpr->pLeft);
+ sqlite3ExprCode(pParse, pExpr->pRight);
+ codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op, 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:
+ case TK_LSHIFT:
+ case TK_RSHIFT:
+ case TK_CONCAT: {
+ assert( TK_AND==OP_And );
+ assert( TK_OR==OP_Or );
+ assert( TK_PLUS==OP_Add );
+ assert( TK_MINUS==OP_Subtract );
+ assert( TK_REM==OP_Remainder );
+ assert( TK_BITAND==OP_BitAnd );
+ assert( TK_BITOR==OP_BitOr );
+ assert( TK_SLASH==OP_Divide );
+ assert( TK_LSHIFT==OP_ShiftLeft );
+ assert( TK_RSHIFT==OP_ShiftRight );
+ assert( TK_CONCAT==OP_Concat );
+ sqlite3ExprCode(pParse, pExpr->pLeft);
+ sqlite3ExprCode(pParse, pExpr->pRight);
+ sqlite3VdbeAddOp(v, op, 0, 0);
+ break;
+ }
+ case TK_UMINUS: {
+ Expr *pLeft = pExpr->pLeft;
+ assert( pLeft );
+ if( pLeft->op==TK_FLOAT || pLeft->op==TK_INTEGER ){
+ Token *p = &pLeft->token;
+ char *z = sqliteMalloc( p->n + 2 );
+ sprintf(z, "-%.*s", p->n, p->z);
+ if( pLeft->op==TK_FLOAT ){
+ sqlite3VdbeOp3(v, OP_Real, 0, 0, z, p->n+1);
+ }else{
+ codeInteger(v, z, p->n+1);
+ }
+ sqliteFree(z);
+ break;
+ }
+ /* Fall through into TK_NOT */
+ }
+ case TK_BITNOT:
+ case TK_NOT: {
+ assert( TK_BITNOT==OP_BitNot );
+ assert( TK_NOT==OP_Not );
+ sqlite3ExprCode(pParse, pExpr->pLeft);
+ sqlite3VdbeAddOp(v, op, 0, 0);
+ break;
+ }
+ case TK_ISNULL:
+ case TK_NOTNULL: {
+ int dest;
+ assert( TK_ISNULL==OP_IsNull );
+ assert( TK_NOTNULL==OP_NotNull );
+ sqlite3VdbeAddOp(v, OP_Integer, 1, 0);
+ sqlite3ExprCode(pParse, pExpr->pLeft);
+ dest = sqlite3VdbeCurrentAddr(v) + 2;
+ sqlite3VdbeAddOp(v, op, 1, dest);
+ sqlite3VdbeAddOp(v, OP_AddImm, -1, 0);
+ break;
+ }
+ case TK_AGG_FUNCTION: {
+ sqlite3VdbeAddOp(v, OP_AggGet, 0, pExpr->iAgg);
+ break;
+ }
+ case TK_GLOB:
+ case TK_LIKE:
+ case TK_FUNCTION: {
+ ExprList *pList = pExpr->pList;
+ int nExpr = pList ? pList->nExpr : 0;
+ FuncDef *pDef;
+ int nId;
+ const char *zId;
+ int p2 = 0;
+ int i;
+ u8 enc = pParse->db->enc;
+ CollSeq *pColl = 0;
+ getFunctionName(pExpr, &zId, &nId);
+ pDef = sqlite3FindFunction(pParse->db, zId, nId, nExpr, enc, 0);
+ assert( pDef!=0 );
+ nExpr = sqlite3ExprCodeExprList(pParse, pList);
+ for(i=0; i<nExpr && i<32; i++){
+ if( sqlite3ExprIsConstant(pList->a[i].pExpr) ){
+ p2 |= (1<<i);
+ }
+ if( pDef->needCollSeq && !pColl ){
+ pColl = sqlite3ExprCollSeq(pParse, pList->a[i].pExpr);
+ }
+ }
+ if( pDef->needCollSeq ){
+ if( !pColl ) pColl = pParse->db->pDfltColl;
+ sqlite3VdbeOp3(v, OP_CollSeq, 0, 0, (char *)pColl, P3_COLLSEQ);
+ }
+ sqlite3VdbeOp3(v, OP_Function, nExpr, p2, (char*)pDef, P3_FUNCDEF);
+ break;
+ }
+ case TK_SELECT: {
+ sqlite3VdbeAddOp(v, OP_MemLoad, pExpr->iColumn, 0);
+ VdbeComment((v, "# load subquery result"));
+ break;
+ }
+ case TK_IN: {
+ int addr;
+ char affinity;
+
+ /* Figure out the affinity to use to create a key from the results
+ ** of the expression. affinityStr stores a static string suitable for
+ ** P3 of OP_MakeRecord.
+ */
+ affinity = comparisonAffinity(pExpr);
+
+ sqlite3VdbeAddOp(v, OP_Integer, 1, 0);
+
+ /* Code the <expr> from "<expr> IN (...)". The temporary table
+ ** pExpr->iTable contains the values that make up the (...) set.
+ */
+ sqlite3ExprCode(pParse, pExpr->pLeft);
+ addr = sqlite3VdbeCurrentAddr(v);
+ sqlite3VdbeAddOp(v, OP_NotNull, -1, addr+4); /* addr + 0 */
+ sqlite3VdbeAddOp(v, OP_Pop, 2, 0);
+ sqlite3VdbeAddOp(v, OP_String8, 0, 0);
+ sqlite3VdbeAddOp(v, OP_Goto, 0, addr+7);
+ sqlite3VdbeOp3(v, OP_MakeRecord, 1, 0, &affinity, 1); /* addr + 4 */
+ sqlite3VdbeAddOp(v, OP_Found, pExpr->iTable, addr+7);
+ sqlite3VdbeAddOp(v, OP_AddImm, -1, 0); /* addr + 6 */
+
+ break;
+ }
+ case TK_BETWEEN: {
+ Expr *pLeft = pExpr->pLeft;
+ struct ExprList_item *pLItem = pExpr->pList->a;
+ Expr *pRight = pLItem->pExpr;
+ sqlite3ExprCode(pParse, pLeft);
+ sqlite3VdbeAddOp(v, OP_Dup, 0, 0);
+ sqlite3ExprCode(pParse, pRight);
+ codeCompare(pParse, pLeft, pRight, OP_Ge, 0, 0);
+ sqlite3VdbeAddOp(v, OP_Pull, 1, 0);
+ pLItem++;
+ pRight = pLItem->pExpr;
+ sqlite3ExprCode(pParse, pRight);
+ codeCompare(pParse, pLeft, pRight, OP_Le, 0, 0);
+ sqlite3VdbeAddOp(v, OP_And, 0, 0);
+ break;
+ }
+ case TK_UPLUS:
+ case TK_AS: {
+ sqlite3ExprCode(pParse, pExpr->pLeft);
+ break;
+ }
+ case TK_CASE: {
+ int expr_end_label;
+ int jumpInst;
+ int addr;
+ int nExpr;
+ int i;
+ ExprList *pEList;
+ struct ExprList_item *aListelem;
+
+ assert(pExpr->pList);
+ assert((pExpr->pList->nExpr % 2) == 0);
+ assert(pExpr->pList->nExpr > 0);
+ pEList = pExpr->pList;
+ aListelem = pEList->a;
+ nExpr = pEList->nExpr;
+ expr_end_label = sqlite3VdbeMakeLabel(v);
+ if( pExpr->pLeft ){
+ sqlite3ExprCode(pParse, pExpr->pLeft);
+ }
+ for(i=0; i<nExpr; i=i+2){
+ sqlite3ExprCode(pParse, aListelem[i].pExpr);
+ if( pExpr->pLeft ){
+ sqlite3VdbeAddOp(v, OP_Dup, 1, 1);
+ jumpInst = codeCompare(pParse, pExpr->pLeft, aListelem[i].pExpr,
+ OP_Ne, 0, 1);
+ sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
+ }else{
+ jumpInst = sqlite3VdbeAddOp(v, OP_IfNot, 1, 0);
+ }
+ sqlite3ExprCode(pParse, aListelem[i+1].pExpr);
+ sqlite3VdbeAddOp(v, OP_Goto, 0, expr_end_label);
+ addr = sqlite3VdbeCurrentAddr(v);
+ sqlite3VdbeChangeP2(v, jumpInst, addr);
+ }
+ if( pExpr->pLeft ){
+ sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
+ }
+ if( pExpr->pRight ){
+ sqlite3ExprCode(pParse, pExpr->pRight);
+ }else{
+ sqlite3VdbeAddOp(v, OP_String8, 0, 0);
+ }
+ sqlite3VdbeResolveLabel(v, expr_end_label);
+ break;
+ }
+ case TK_RAISE: {
+ if( !pParse->trigStack ){
+ sqlite3ErrorMsg(pParse,
+ "RAISE() may only be used within a trigger-program");
+ return;
+ }
+ if( pExpr->iColumn!=OE_Ignore ){
+ assert( pExpr->iColumn==OE_Rollback ||
+ pExpr->iColumn == OE_Abort ||
+ pExpr->iColumn == OE_Fail );
+ sqlite3VdbeOp3(v, OP_Halt, SQLITE_CONSTRAINT, pExpr->iColumn,
+ pExpr->token.z, pExpr->token.n);
+ sqlite3VdbeDequoteP3(v, -1);
+ } else {
+ assert( pExpr->iColumn == OE_Ignore );
+ sqlite3VdbeAddOp(v, OP_ContextPop, 0, 0);
+ sqlite3VdbeAddOp(v, OP_Goto, 0, pParse->trigStack->ignoreJump);
+ VdbeComment((v, "# raise(IGNORE)"));
+ }
+ }
+ break;
+ }
+}
+
+/*
+** Generate code that pushes the value of every element of the given
+** expression list onto the stack.
+**
+** Return the number of elements pushed onto the stack.
+*/
+int sqlite3ExprCodeExprList(
+ Parse *pParse, /* Parsing context */
+ ExprList *pList /* The expression list to be coded */
+){
+ struct ExprList_item *pItem;
+ int i, n;
+ Vdbe *v;
+ if( pList==0 ) return 0;
+ v = sqlite3GetVdbe(pParse);
+ n = pList->nExpr;
+ for(pItem=pList->a, i=0; i<n; i++, pItem++){
+ sqlite3ExprCode(pParse, pItem->pExpr);
+ }
+ return n;
+}
+
+/*
+** 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.
+**
+** If the expression evaluates to NULL (neither true nor false), then
+** take the jump if the jumpIfNull flag is true.
+**
+** This code depends on the fact that certain token values (ex: TK_EQ)
+** are the same as opcode values (ex: OP_Eq) that implement the corresponding
+** operation. Special comments in vdbe.c and the mkopcodeh.awk script in
+** the make process cause these values to align. Assert()s in the code
+** below verify that the numbers are aligned correctly.
+*/
+void sqlite3ExprIfTrue(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
+ Vdbe *v = pParse->pVdbe;
+ int op = 0;
+ if( v==0 || pExpr==0 ) return;
+ op = pExpr->op;
+ switch( op ){
+ case TK_AND: {
+ int d2 = sqlite3VdbeMakeLabel(v);
+ sqlite3ExprIfFalse(pParse, pExpr->pLeft, d2, !jumpIfNull);
+ sqlite3ExprIfTrue(pParse, pExpr->pRight, dest, jumpIfNull);
+ sqlite3VdbeResolveLabel(v, d2);
+ break;
+ }
+ case TK_OR: {
+ sqlite3ExprIfTrue(pParse, pExpr->pLeft, dest, jumpIfNull);
+ sqlite3ExprIfTrue(pParse, pExpr->pRight, dest, jumpIfNull);
+ break;
+ }
+ case TK_NOT: {
+ sqlite3ExprIfFalse(pParse, pExpr->pLeft, dest, jumpIfNull);
+ break;
+ }
+ case TK_LT:
+ case TK_LE:
+ case TK_GT:
+ case TK_GE:
+ case TK_NE:
+ case TK_EQ: {
+ assert( TK_LT==OP_Lt );
+ assert( TK_LE==OP_Le );
+ assert( TK_GT==OP_Gt );
+ assert( TK_GE==OP_Ge );
+ assert( TK_EQ==OP_Eq );
+ assert( TK_NE==OP_Ne );
+ sqlite3ExprCode(pParse, pExpr->pLeft);
+ sqlite3ExprCode(pParse, pExpr->pRight);
+ codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op, dest, jumpIfNull);
+ break;
+ }
+ case TK_ISNULL:
+ case TK_NOTNULL: {
+ assert( TK_ISNULL==OP_IsNull );
+ assert( TK_NOTNULL==OP_NotNull );
+ sqlite3ExprCode(pParse, pExpr->pLeft);
+ sqlite3VdbeAddOp(v, op, 1, dest);
+ break;
+ }
+ case TK_BETWEEN: {
+ /* The expression "x BETWEEN y AND z" is implemented as:
+ **
+ ** 1 IF (x < y) GOTO 3
+ ** 2 IF (x <= z) GOTO <dest>
+ ** 3 ...
+ */
+ int addr;
+ Expr *pLeft = pExpr->pLeft;
+ Expr *pRight = pExpr->pList->a[0].pExpr;
+ sqlite3ExprCode(pParse, pLeft);
+ sqlite3VdbeAddOp(v, OP_Dup, 0, 0);
+ sqlite3ExprCode(pParse, pRight);
+ addr = codeCompare(pParse, pLeft, pRight, OP_Lt, 0, !jumpIfNull);
+
+ pRight = pExpr->pList->a[1].pExpr;
+ sqlite3ExprCode(pParse, pRight);
+ codeCompare(pParse, pLeft, pRight, OP_Le, dest, jumpIfNull);
+
+ sqlite3VdbeAddOp(v, OP_Integer, 0, 0);
+ sqlite3VdbeChangeP2(v, addr, sqlite3VdbeCurrentAddr(v));
+ sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
+ break;
+ }
+ default: {
+ sqlite3ExprCode(pParse, pExpr);
+ sqlite3VdbeAddOp(v, OP_If, jumpIfNull, 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.
+**
+** If the expression evaluates to NULL (neither true nor false) then
+** jump if jumpIfNull is true or fall through if jumpIfNull is false.
+*/
+void sqlite3ExprIfFalse(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
+ Vdbe *v = pParse->pVdbe;
+ int op = 0;
+ if( v==0 || pExpr==0 ) return;
+
+ /* The value of pExpr->op and op are related as follows:
+ **
+ ** pExpr->op op
+ ** --------- ----------
+ ** TK_ISNULL OP_NotNull
+ ** TK_NOTNULL OP_IsNull
+ ** TK_NE OP_Eq
+ ** TK_EQ OP_Ne
+ ** TK_GT OP_Le
+ ** TK_LE OP_Gt
+ ** TK_GE OP_Lt
+ ** TK_LT OP_Ge
+ **
+ ** For other values of pExpr->op, op is undefined and unused.
+ ** The value of TK_ and OP_ constants are arranged such that we
+ ** can compute the mapping above using the following expression.
+ ** Assert()s verify that the computation is correct.
+ */
+ op = ((pExpr->op+(TK_ISNULL&1))^1)-(TK_ISNULL&1);
+
+ /* Verify correct alignment of TK_ and OP_ constants
+ */
+ assert( pExpr->op!=TK_ISNULL || op==OP_NotNull );
+ assert( pExpr->op!=TK_NOTNULL || op==OP_IsNull );
+ assert( pExpr->op!=TK_NE || op==OP_Eq );
+ assert( pExpr->op!=TK_EQ || op==OP_Ne );
+ assert( pExpr->op!=TK_LT || op==OP_Ge );
+ assert( pExpr->op!=TK_LE || op==OP_Gt );
+ assert( pExpr->op!=TK_GT || op==OP_Le );
+ assert( pExpr->op!=TK_GE || op==OP_Lt );
+
+ switch( pExpr->op ){
+ case TK_AND: {
+ sqlite3ExprIfFalse(pParse, pExpr->pLeft, dest, jumpIfNull);
+ sqlite3ExprIfFalse(pParse, pExpr->pRight, dest, jumpIfNull);
+ break;
+ }
+ case TK_OR: {
+ int d2 = sqlite3VdbeMakeLabel(v);
+ sqlite3ExprIfTrue(pParse, pExpr->pLeft, d2, !jumpIfNull);
+ sqlite3ExprIfFalse(pParse, pExpr->pRight, dest, jumpIfNull);
+ sqlite3VdbeResolveLabel(v, d2);
+ break;
+ }
+ case TK_NOT: {
+ sqlite3ExprIfTrue(pParse, pExpr->pLeft, dest, jumpIfNull);
+ break;
+ }
+ case TK_LT:
+ case TK_LE:
+ case TK_GT:
+ case TK_GE:
+ case TK_NE:
+ case TK_EQ: {
+ sqlite3ExprCode(pParse, pExpr->pLeft);
+ sqlite3ExprCode(pParse, pExpr->pRight);
+ codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op, dest, jumpIfNull);
+ break;
+ }
+ case TK_ISNULL:
+ case TK_NOTNULL: {
+ sqlite3ExprCode(pParse, pExpr->pLeft);
+ sqlite3VdbeAddOp(v, op, 1, dest);
+ break;
+ }
+ case TK_BETWEEN: {
+ /* The expression is "x BETWEEN y AND z". It is implemented as:
+ **
+ ** 1 IF (x >= y) GOTO 3
+ ** 2 GOTO <dest>
+ ** 3 IF (x > z) GOTO <dest>
+ */
+ int addr;
+ Expr *pLeft = pExpr->pLeft;
+ Expr *pRight = pExpr->pList->a[0].pExpr;
+ sqlite3ExprCode(pParse, pLeft);
+ sqlite3VdbeAddOp(v, OP_Dup, 0, 0);
+ sqlite3ExprCode(pParse, pRight);
+ addr = sqlite3VdbeCurrentAddr(v);
+ codeCompare(pParse, pLeft, pRight, OP_Ge, addr+3, !jumpIfNull);
+
+ sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
+ sqlite3VdbeAddOp(v, OP_Goto, 0, dest);
+ pRight = pExpr->pList->a[1].pExpr;
+ sqlite3ExprCode(pParse, pRight);
+ codeCompare(pParse, pLeft, pRight, OP_Gt, dest, jumpIfNull);
+ break;
+ }
+ default: {
+ sqlite3ExprCode(pParse, pExpr);
+ sqlite3VdbeAddOp(v, OP_IfNot, jumpIfNull, 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 sqlite3ExprCompare(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( !sqlite3ExprCompare(pA->pLeft, pB->pLeft) ) return 0;
+ if( !sqlite3ExprCompare(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( !sqlite3ExprCompare(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->iTable!=pB->iTable || pA->iColumn!=pB->iColumn ) return 0;
+ if( pA->token.z ){
+ if( pB->token.z==0 ) return 0;
+ if( pB->token.n!=pA->token.n ) return 0;
+ if( sqlite3StrNICmp(pA->token.z, pB->token.z, pB->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 sqlite3ExprResolveIds() and sqlite3ExprCheck().
+**
+** If errors are seen, leave an error message in zErrMsg and return
+** the number of errors.
+*/
+int sqlite3ExprAnalyzeAggregates(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: {
+ aAgg = pParse->aAgg;
+ for(i=0; i<pParse->nAgg; i++){
+ if( !aAgg[i].isAgg ) continue;
+ if( sqlite3ExprCompare(aAgg[i].pExpr, pExpr) ){
+ break;
+ }
+ }
+ if( i>=pParse->nAgg ){
+ u8 enc = pParse->db->enc;
+ i = appendAggInfo(pParse);
+ if( i<0 ) return 1;
+ pParse->aAgg[i].isAgg = 1;
+ pParse->aAgg[i].pExpr = pExpr;
+ pParse->aAgg[i].pFunc = sqlite3FindFunction(pParse->db,
+ pExpr->token.z, pExpr->token.n,
+ pExpr->pList ? pExpr->pList->nExpr : 0, enc, 0);
+ }
+ pExpr->iAgg = i;
+ break;
+ }
+ default: {
+ if( pExpr->pLeft ){
+ nErr = sqlite3ExprAnalyzeAggregates(pParse, pExpr->pLeft);
+ }
+ if( nErr==0 && pExpr->pRight ){
+ nErr = sqlite3ExprAnalyzeAggregates(pParse, pExpr->pRight);
+ }
+ if( nErr==0 && pExpr->pList ){
+ int n = pExpr->pList->nExpr;
+ int i;
+ for(i=0; nErr==0 && i<n; i++){
+ nErr = sqlite3ExprAnalyzeAggregates(pParse, pExpr->pList->a[i].pExpr);
+ }
+ }
+ break;
+ }
+ }
+ return nErr;
+}
+
+/*
+** Locate a user function given a name, a number of arguments and a flag
+** indicating whether the function prefers UTF-16 over UTF-8. Return a
+** pointer to the FuncDef structure that defines that function, or return
+** NULL if the function does not exist.
+**
+** If the createFlag argument is true, then a new (blank) FuncDef
+** 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.
+**
+** If createFlag is false, then a function with the required name and
+** number of arguments may be returned even if the eTextRep flag does not
+** match that requested.
+*/
+FuncDef *sqlite3FindFunction(
+ sqlite3 *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 */
+ u8 enc, /* Preferred text encoding */
+ int createFlag /* Create new entry if true and does not otherwise exist */
+){
+ FuncDef *p; /* Iterator variable */
+ FuncDef *pFirst; /* First function with this name */
+ FuncDef *pBest = 0; /* Best match found so far */
+ int bestmatch = 0;
+
+
+ assert( enc==SQLITE_UTF8 || enc==SQLITE_UTF16LE || enc==SQLITE_UTF16BE );
+ if( nArg<-1 ) nArg = -1;
+
+ pFirst = (FuncDef*)sqlite3HashFind(&db->aFunc, zName, nName);
+ for(p=pFirst; p; p=p->pNext){
+ /* During the search for the best function definition, bestmatch is set
+ ** as follows to indicate the quality of the match with the definition
+ ** pointed to by pBest:
+ **
+ ** 0: pBest is NULL. No match has been found.
+ ** 1: A variable arguments function that prefers UTF-8 when a UTF-16
+ ** encoding is requested, or vice versa.
+ ** 2: A variable arguments function that uses UTF-16BE when UTF-16LE is
+ ** requested, or vice versa.
+ ** 3: A variable arguments function using the same text encoding.
+ ** 4: A function with the exact number of arguments requested that
+ ** prefers UTF-8 when a UTF-16 encoding is requested, or vice versa.
+ ** 5: A function with the exact number of arguments requested that
+ ** prefers UTF-16LE when UTF-16BE is requested, or vice versa.
+ ** 6: An exact match.
+ **
+ ** A larger value of 'matchqual' indicates a more desirable match.
+ */
+ if( p->nArg==-1 || p->nArg==nArg || nArg==-1 ){
+ int match = 1; /* Quality of this match */
+ if( p->nArg==nArg || nArg==-1 ){
+ match = 4;
+ }
+ if( enc==p->iPrefEnc ){
+ match += 2;
+ }
+ else if( (enc==SQLITE_UTF16LE && p->iPrefEnc==SQLITE_UTF16BE) ||
+ (enc==SQLITE_UTF16BE && p->iPrefEnc==SQLITE_UTF16LE) ){
+ match += 1;
+ }
+
+ if( match>bestmatch ){
+ pBest = p;
+ bestmatch = match;
+ }
+ }
+ }
+
+ /* If the createFlag parameter is true, and the seach did not reveal an
+ ** exact match for the name, number of arguments and encoding, then add a
+ ** new entry to the hash table and return it.
+ */
+ if( createFlag && bestmatch<6 &&
+ (pBest = sqliteMalloc(sizeof(*pBest)+nName+1)) ){
+ pBest->nArg = nArg;
+ pBest->pNext = pFirst;
+ pBest->zName = (char*)&pBest[1];
+ pBest->iPrefEnc = enc;
+ memcpy(pBest->zName, zName, nName);
+ pBest->zName[nName] = 0;
+ sqlite3HashInsert(&db->aFunc, pBest->zName, nName, (void*)pBest);
+ }
+
+ if( pBest && (pBest->xStep || pBest->xFunc || createFlag) ){
+ return pBest;
+ }
+ return 0;
+}