diff options
Diffstat (limited to 'src/expr.c')
| -rw-r--r-- | src/expr.c | 103 |
1 files changed, 1 insertions, 102 deletions
diff --git a/src/expr.c b/src/expr.c index 7373fdc57..84acbb1f6 100644 --- a/src/expr.c +++ b/src/expr.c @@ -12,7 +12,7 @@ ** This file contains routines used for analyzing expressions and ** for generating VDBE code that evaluates expressions in SQLite. ** -** $Id: expr.c,v 1.200 2005/05/23 17:26:51 drh Exp $ +** $Id: expr.c,v 1.201 2005/05/24 12:01:02 danielk1977 Exp $ */ #include "sqliteInt.h" #include <ctype.h> @@ -2049,104 +2049,3 @@ int sqlite3ExprAnalyzeAggregates(NameContext *pNC, Expr *pExpr){ walkExprTree(pExpr, analyzeAggregate, pNC); return pNC->pParse->nErr - 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; - if( pBest==sqlite3HashInsert(&db->aFunc,pBest->zName,nName,(void*)pBest) ){ - sqliteFree(pBest); - return 0; - } - } - - if( pBest && (pBest->xStep || pBest->xFunc || createFlag) ){ - return pBest; - } - return 0; -} |