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Move a few things around to make building without the parser easier. (CVS 2479)
FossilOrigin-Name: 5fadb464eb77b4b998d8555f83401769960ea904
This commit is contained in:
danielk1977
190
src/callback.c
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190
src/callback.c
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/*
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** 2005 May 23
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**
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** The author disclaims copyright to this source code. In place of
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** a legal notice, here is a blessing:
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**
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** May you do good and not evil.
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** May you find forgiveness for yourself and forgive others.
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** May you share freely, never taking more than you give.
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**
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*************************************************************************
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**
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** This file contains functions used to access the internal hash tables
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** of user defined functions and collation sequences.
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**
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** $Id: callback.c,v 1.1 2005/05/24 12:01:02 danielk1977 Exp $
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*/
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#include "sqliteInt.h"
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/*
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** Locate and return an entry from the db.aCollSeq hash table. If the entry
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** specified by zName and nName is not found and parameter 'create' is
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** true, then create a new entry. Otherwise return NULL.
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**
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** Each pointer stored in the sqlite3.aCollSeq hash table contains an
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** array of three CollSeq structures. The first is the collation sequence
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** prefferred for UTF-8, the second UTF-16le, and the third UTF-16be.
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**
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** Stored immediately after the three collation sequences is a copy of
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** the collation sequence name. A pointer to this string is stored in
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** each collation sequence structure.
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*/
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static CollSeq * findCollSeqEntry(
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sqlite3 *db,
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const char *zName,
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int nName,
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int create
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){
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CollSeq *pColl;
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if( nName<0 ) nName = strlen(zName);
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pColl = sqlite3HashFind(&db->aCollSeq, zName, nName);
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if( 0==pColl && create ){
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pColl = sqliteMalloc( 3*sizeof(*pColl) + nName + 1 );
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if( pColl ){
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CollSeq *pDel = 0;
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pColl[0].zName = (char*)&pColl[3];
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pColl[0].enc = SQLITE_UTF8;
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pColl[1].zName = (char*)&pColl[3];
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pColl[1].enc = SQLITE_UTF16LE;
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pColl[2].zName = (char*)&pColl[3];
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pColl[2].enc = SQLITE_UTF16BE;
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memcpy(pColl[0].zName, zName, nName);
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pColl[0].zName[nName] = 0;
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pDel = sqlite3HashInsert(&db->aCollSeq, pColl[0].zName, nName, pColl);
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/* If a malloc() failure occured in sqlite3HashInsert(), it will
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** return the pColl pointer to be deleted (because it wasn't added
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** to the hash table).
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*/
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assert( !pDel || (sqlite3_malloc_failed && pDel==pColl) );
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sqliteFree(pDel);
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}
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}
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return pColl;
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}
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/*
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** Parameter zName points to a UTF-8 encoded string nName bytes long.
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** Return the CollSeq* pointer for the collation sequence named zName
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** for the encoding 'enc' from the database 'db'.
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**
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** If the entry specified is not found and 'create' is true, then create a
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** new entry. Otherwise return NULL.
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*/
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CollSeq *sqlite3FindCollSeq(
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sqlite3 *db,
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u8 enc,
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const char *zName,
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int nName,
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int create
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){
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CollSeq *pColl = findCollSeqEntry(db, zName, nName, create);
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assert( SQLITE_UTF8==1 && SQLITE_UTF16LE==2 && SQLITE_UTF16BE==3 );
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assert( enc>=SQLITE_UTF8 && enc<=SQLITE_UTF16BE );
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if( pColl ) pColl += enc-1;
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return pColl;
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}
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/*
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** Locate a user function given a name, a number of arguments and a flag
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** indicating whether the function prefers UTF-16 over UTF-8. Return a
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** pointer to the FuncDef structure that defines that function, or return
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** NULL if the function does not exist.
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**
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** If the createFlag argument is true, then a new (blank) FuncDef
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** structure is created and liked into the "db" structure if a
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** no matching function previously existed. When createFlag is true
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** and the nArg parameter is -1, then only a function that accepts
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** any number of arguments will be returned.
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**
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** If createFlag is false and nArg is -1, then the first valid
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** function found is returned. A function is valid if either xFunc
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** or xStep is non-zero.
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**
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** If createFlag is false, then a function with the required name and
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** number of arguments may be returned even if the eTextRep flag does not
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** match that requested.
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*/
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FuncDef *sqlite3FindFunction(
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sqlite3 *db, /* An open database */
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const char *zName, /* Name of the function. Not null-terminated */
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int nName, /* Number of characters in the name */
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int nArg, /* Number of arguments. -1 means any number */
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u8 enc, /* Preferred text encoding */
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int createFlag /* Create new entry if true and does not otherwise exist */
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){
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FuncDef *p; /* Iterator variable */
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FuncDef *pFirst; /* First function with this name */
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FuncDef *pBest = 0; /* Best match found so far */
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int bestmatch = 0;
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assert( enc==SQLITE_UTF8 || enc==SQLITE_UTF16LE || enc==SQLITE_UTF16BE );
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if( nArg<-1 ) nArg = -1;
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pFirst = (FuncDef*)sqlite3HashFind(&db->aFunc, zName, nName);
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for(p=pFirst; p; p=p->pNext){
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/* During the search for the best function definition, bestmatch is set
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** as follows to indicate the quality of the match with the definition
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** pointed to by pBest:
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**
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** 0: pBest is NULL. No match has been found.
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** 1: A variable arguments function that prefers UTF-8 when a UTF-16
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** encoding is requested, or vice versa.
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** 2: A variable arguments function that uses UTF-16BE when UTF-16LE is
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** requested, or vice versa.
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** 3: A variable arguments function using the same text encoding.
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** 4: A function with the exact number of arguments requested that
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** prefers UTF-8 when a UTF-16 encoding is requested, or vice versa.
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** 5: A function with the exact number of arguments requested that
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** prefers UTF-16LE when UTF-16BE is requested, or vice versa.
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** 6: An exact match.
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**
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** A larger value of 'matchqual' indicates a more desirable match.
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*/
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if( p->nArg==-1 || p->nArg==nArg || nArg==-1 ){
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int match = 1; /* Quality of this match */
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if( p->nArg==nArg || nArg==-1 ){
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match = 4;
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}
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if( enc==p->iPrefEnc ){
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match += 2;
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}
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else if( (enc==SQLITE_UTF16LE && p->iPrefEnc==SQLITE_UTF16BE) ||
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(enc==SQLITE_UTF16BE && p->iPrefEnc==SQLITE_UTF16LE) ){
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match += 1;
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}
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if( match>bestmatch ){
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pBest = p;
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bestmatch = match;
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}
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}
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}
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/* If the createFlag parameter is true, and the seach did not reveal an
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** exact match for the name, number of arguments and encoding, then add a
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** new entry to the hash table and return it.
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*/
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if( createFlag && bestmatch<6 &&
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(pBest = sqliteMalloc(sizeof(*pBest)+nName+1)) ){
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pBest->nArg = nArg;
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pBest->pNext = pFirst;
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pBest->zName = (char*)&pBest[1];
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pBest->iPrefEnc = enc;
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memcpy(pBest->zName, zName, nName);
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pBest->zName[nName] = 0;
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if( pBest==sqlite3HashInsert(&db->aFunc,pBest->zName,nName,(void*)pBest) ){
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sqliteFree(pBest);
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return 0;
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}
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}
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if( pBest && (pBest->xStep || pBest->xFunc || createFlag) ){
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return pBest;
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}
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return 0;
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}
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