Initial commit

Signed-off-by: Mavridis Philippe <[email protected]>

1 files changed, 306 insertions, 0 deletions

diff --git a/src/sqlite/callback.c b/src/sqlite/callback.c
new file mode 100644
index 0000000..a90fdf6
--- /dev/null
+++ b/src/sqlite/callback.c
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+/*
+** 2005 May 23 
+**
+** 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 functions used to access the internal hash tables
+** of user defined functions and collation sequences.
+**
+** $Id: callback.c,v 1.1.1.1 2006/02/03 20:35:09 hoganrobert Exp $
+*/
+
+#include "sqliteInt.h"
+
+/*
+** Invoke the 'collation needed' callback to request a collation sequence
+** in the database text encoding of name zName, length nName.
+** If the collation sequence
+*/
+static void callCollNeeded(sqlite3 *db, const char *zName, int nName){
+  assert( !db->xCollNeeded || !db->xCollNeeded16 );
+  if( nName<0 ) nName = strlen(zName);
+  if( db->xCollNeeded ){
+    char *zExternal = sqliteStrNDup(zName, nName);
+    if( !zExternal ) return;
+    db->xCollNeeded(db->pCollNeededArg, db, (int)db->enc, zExternal);
+    sqliteFree(zExternal);
+  }
+#ifndef SQLITE_OMIT_UTF16
+  if( db->xCollNeeded16 ){
+    char const *zExternal;
+    sqlite3_value *pTmp = sqlite3GetTransientValue(db);
+    sqlite3ValueSetStr(pTmp, -1, zName, SQLITE_UTF8, SQLITE_STATIC);
+    zExternal = sqlite3ValueText(pTmp, SQLITE_UTF16NATIVE);
+    if( !zExternal ) return;
+    db->xCollNeeded16(db->pCollNeededArg, db, (int)db->enc, zExternal);
+  }
+#endif
+}
+
+/*
+** This routine is called if the collation factory fails to deliver a
+** collation function in the best encoding but there may be other versions
+** of this collation function (for other text encodings) available. Use one
+** of these instead if they exist. Avoid a UTF-8 <-> UTF-16 conversion if
+** possible.
+*/
+static int synthCollSeq(sqlite3 *db, CollSeq *pColl){
+  CollSeq *pColl2;
+  char *z = pColl->zName;
+  int n = strlen(z);
+  int i;
+  static const u8 aEnc[] = { SQLITE_UTF16BE, SQLITE_UTF16LE, SQLITE_UTF8 };
+  for(i=0; i<3; i++){
+    pColl2 = sqlite3FindCollSeq(db, aEnc[i], z, n, 0);
+    if( pColl2->xCmp!=0 ){
+      memcpy(pColl, pColl2, sizeof(CollSeq));
+      return SQLITE_OK;
+    }
+  }
+  return SQLITE_ERROR;
+}
+
+/*
+** This function is responsible for invoking the collation factory callback
+** or substituting a collation sequence of a different encoding when the
+** requested collation sequence is not available in the database native
+** encoding.
+** 
+** If it is not NULL, then pColl must point to the database native encoding 
+** collation sequence with name zName, length nName.
+**
+** The return value is either the collation sequence to be used in database
+** db for collation type name zName, length nName, or NULL, if no collation
+** sequence can be found.
+*/
+CollSeq *sqlite3GetCollSeq(
+  sqlite3* db, 
+  CollSeq *pColl, 
+  const char *zName, 
+  int nName
+){
+  CollSeq *p;
+
+  p = pColl;
+  if( !p ){
+    p = sqlite3FindCollSeq(db, db->enc, zName, nName, 0);
+  }
+  if( !p || !p->xCmp ){
+    /* No collation sequence of this type for this encoding is registered.
+    ** Call the collation factory to see if it can supply us with one.
+    */
+    callCollNeeded(db, zName, nName);
+    p = sqlite3FindCollSeq(db, db->enc, zName, nName, 0);
+  }
+  if( p && !p->xCmp && synthCollSeq(db, p) ){
+    p = 0;
+  }
+  assert( !p || p->xCmp );
+  return p;
+}
+
+/*
+** This routine is called on a collation sequence before it is used to
+** check that it is defined. An undefined collation sequence exists when
+** a database is loaded that contains references to collation sequences
+** that have not been defined by sqlite3_create_collation() etc.
+**
+** If required, this routine calls the 'collation needed' callback to
+** request a definition of the collating sequence. If this doesn't work, 
+** an equivalent collating sequence that uses a text encoding different
+** from the main database is substituted, if one is available.
+*/
+int sqlite3CheckCollSeq(Parse *pParse, CollSeq *pColl){
+  if( pColl ){
+    const char *zName = pColl->zName;
+    CollSeq *p = sqlite3GetCollSeq(pParse->db, pColl, zName, -1);
+    if( !p ){
+      if( pParse->nErr==0 ){
+        sqlite3ErrorMsg(pParse, "no such collation sequence: %s", zName);
+      }
+      pParse->nErr++;
+      return SQLITE_ERROR;
+    }
+  }
+  return SQLITE_OK;
+}
+
+
+
+/*
+** Locate and return an entry from the db.aCollSeq hash table. If the entry
+** specified by zName and nName is not found and parameter 'create' is
+** true, then create a new entry. Otherwise return NULL.
+**
+** Each pointer stored in the sqlite3.aCollSeq hash table contains an
+** array of three CollSeq structures. The first is the collation sequence
+** prefferred for UTF-8, the second UTF-16le, and the third UTF-16be.
+**
+** Stored immediately after the three collation sequences is a copy of
+** the collation sequence name. A pointer to this string is stored in
+** each collation sequence structure.
+*/
+static CollSeq * findCollSeqEntry(
+  sqlite3 *db,
+  const char *zName,
+  int nName,
+  int create
+){
+  CollSeq *pColl;
+  if( nName<0 ) nName = strlen(zName);
+  pColl = sqlite3HashFind(&db->aCollSeq, zName, nName);
+
+  if( 0==pColl && create ){
+    pColl = sqliteMalloc( 3*sizeof(*pColl) + nName + 1 );
+    if( pColl ){
+      CollSeq *pDel = 0;
+      pColl[0].zName = (char*)&pColl[3];
+      pColl[0].enc = SQLITE_UTF8;
+      pColl[1].zName = (char*)&pColl[3];
+      pColl[1].enc = SQLITE_UTF16LE;
+      pColl[2].zName = (char*)&pColl[3];
+      pColl[2].enc = SQLITE_UTF16BE;
+      memcpy(pColl[0].zName, zName, nName);
+      pColl[0].zName[nName] = 0;
+      pDel = sqlite3HashInsert(&db->aCollSeq, pColl[0].zName, nName, pColl);
+
+      /* If a malloc() failure occured in sqlite3HashInsert(), it will 
+      ** return the pColl pointer to be deleted (because it wasn't added
+      ** to the hash table).
+      */
+      assert( !pDel || (sqlite3_malloc_failed && pDel==pColl) );
+      sqliteFree(pDel);
+    }
+  }
+  return pColl;
+}
+
+/*
+** Parameter zName points to a UTF-8 encoded string nName bytes long.
+** Return the CollSeq* pointer for the collation sequence named zName
+** for the encoding 'enc' from the database 'db'.
+**
+** If the entry specified is not found and 'create' is true, then create a
+** new entry.  Otherwise return NULL.
+*/
+CollSeq *sqlite3FindCollSeq(
+  sqlite3 *db,
+  u8 enc,
+  const char *zName,
+  int nName,
+  int create
+){
+  CollSeq *pColl = findCollSeqEntry(db, zName, nName, create);
+  assert( SQLITE_UTF8==1 && SQLITE_UTF16LE==2 && SQLITE_UTF16BE==3 );
+  assert( enc>=SQLITE_UTF8 && enc<=SQLITE_UTF16BE );
+  if( pColl ) pColl += enc-1;
+  return pColl;
+}
+
+/*
+** 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;
+}