SQLite

**    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: expr.c,v 1.37 2002/01/06 17:07:40 drh Exp $
*/
#include "sqliteInt.h"

/*
** Walk an expression tree.  Return 1 if the expression is constant
** and 0 if it involves variables.
*/

** Walk the expression tree and process operators of the form:
**
**       expr IN (SELECT ...)
**
** These operators have to be processed before column names are
** resolved because each such operator increments pParse->nTab
** to reserve cursor numbers for its own use.  But pParse->nTab
** needs to be constant once we begin resolving column names.  For
** that reason, this procedure needs to be called on every expression
** before sqliteExprResolveIds() is called on any expression.
**
** Actually, the processing of IN-SELECT is only started by this
** routine.  This routine allocates a cursor number to the IN-SELECT
** and then moves on.  The code generation is done by 
** sqliteExprResolveIds() which must be called afterwards.
*/
void sqliteExprResolveInSelect(Parse *pParse, Expr *pExpr){

  if( sqliteStrICmp(z, "OID")==0 ) return 1;
  return 0;
}

/*
** 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 pParse->nTab value.  This 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 ...)

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This is the implementation of generic hash-tables
** used in SQLite.
**
** $Id: hash.c,v 1.5 2002/01/06 17:07:40 drh Exp $
*/
#include "sqliteInt.h"
#include <assert.h>

/* Turn bulk memory into a hash table object by initializing the
** fields of the Hash structure.
**
** "new" is a pointer to the hash table that is to be initialized.
** keyClass is one of the constants SQLITE_HASH_INT, SQLITE_HASH_POINTER,
** SQLITE_HASH_BINARY, or SQLITE_HASH_STRING.  The value of keyClass 
** determines what kind of key the hash table will use.  "copyKey" is
** true if the hash table should make its own private copy of keys and
** false if it should just use the supplied pointer.  CopyKey only makes
** sense for SQLITE_HASH_STRING and SQLITE_HASH_BINARY and is ignored
** for other key classes.
*/
void sqliteHashInit(Hash *new, int keyClass, int copyKey){
  assert( new!=0 );
  assert( keyClass>=SQLITE_HASH_INT && keyClass<=SQLITE_HASH_BINARY );
  new->keyClass = keyClass;
  new->copyKey = copyKey &&
                (keyClass==SQLITE_HASH_STRING || keyClass==SQLITE_HASH_BINARY);
  new->first = 0;
  new->count = 0;
  new->htsize = 0;
  new->ht = 0;
}

/* Remove all entries from a hash table.  Reclaim all memory.
** Call this routine to delete a hash table or to reset a hash table
** to the empty state.
*/
void sqliteHashClear(Hash *pH){
  HashElem *elem;         /* For looping over all elements of the table */

  assert( pH!=0 );
  elem = pH->first;
  pH->first = 0;

static int binCompare(const void *pKey1, int n1, const void *pKey2, int n2){
  if( n1!=n2 ) return n2-n1;
  return memcmp(pKey1,pKey2,n1);
}

/*
** Return a pointer to the appropriate hash function given the key class.
**
** The C syntax in this function definition may be unfamilar to some 
** programmers, so we provide the following additional explanation:
**
** The name of the function is "hashFunction".  The function takes a
** single parameter "keyClass".  The return value of hashFunction()
** is a pointer to another function.  Specifically, the return value
** of hashFunction() is a pointer to a function that takes two parameters
** with types "const void*" and "int" and returns an "int".
*/
static int (*hashFunction(int keyClass))(const void*,int){
  switch( keyClass ){
    case SQLITE_HASH_INT:     return intHash;
    case SQLITE_HASH_POINTER: return ptrHash;
    case SQLITE_HASH_STRING:  return strHash;
    case SQLITE_HASH_BINARY:  return binHash;;
    default: break;
  }
  return 0;
}

/*
** Return a pointer to the appropriate hash function given the key class.
**
** For help in interpreted the obscure C code in the function definition,
** see the header comment on the previous function.
*/
static int (*compareFunction(int keyClass))(const void*,int,const void*,int){
  switch( keyClass ){
    case SQLITE_HASH_INT:     return intCompare;
    case SQLITE_HASH_POINTER: return ptrCompare;
    case SQLITE_HASH_STRING:  return strCompare;
    case SQLITE_HASH_BINARY:  return binCompare;
    default: break;
  }
  return 0;
}


/* Resize the hash table so that it cantains "new_size" buckets.
** "new_size" must be a power of 2.  The hash table might fail 
** to resize if sqliteMalloc() fails.
*/
static void rehash(Hash *pH, int new_size){
  struct _ht *new_ht;            /* The new hash table */
  HashElem *elem, *next_elem;    /* For looping over existing elements */
  HashElem *x;                   /* Element being copied to new hash table */
  int (*xHash)(const void*,int); /* The hash function */

    }
    new_ht[h].chain = elem;
    new_ht[h].count++;
  }
}

/* This function (for internal use only) locates an element in an
** hash table that matches the given key.  The hash for this key has
** already been computed and is passed as the 4th parameter.
*/
static HashElem *findElementGivenHash(
  const Hash *pH,     /* The pH to be searched */
  const void *pKey,   /* The key we are searching for */
  int nKey,
  int h               /* The hash for this key. */
){

/* Remove a single entry from the hash table given a pointer to that
** element and a hash on the element's key.
*/
static void removeElementGivenHash(
  Hash *pH,         /* The pH containing "elem" */
  HashElem* elem,   /* The element to be removed from the pH */
  int h             /* Hash value for the element */
){
  if( elem->prev ){
    elem->prev->next = elem->next; 
  }else{
    pH->first = elem->next;
  }
  if( elem->next ){

  if( pH->copyKey && elem->pKey ){
    sqliteFree(elem->pKey);
  }
  sqliteFree( elem );
  pH->count--;
}

/* Attempt to locate an element of the hash table pH with a key
** that matches pKey,nKey.  Return the data for this element if it is
** found, or NULL if there is no match.
*/
void *sqliteHashFind(const Hash *pH, const void *pKey, int nKey){
  int h;             /* A hash on key */
  HashElem *elem;    /* The element that matches key */
  int (*xHash)(const void*,int);  /* The hash function */

  if( pH==0 || pH->ht==0 ) return 0;

** If no element exists with a matching key, then a new
** element is created.  A copy of the key is made if the copyKey
** flag is set.  NULL is returned.
**
** If another element already exists with the same key, then the
** new data replaces the old data and the old data is returned.
** The key is not copied in this instance.  If a malloc fails, then
** the new data is returned and the hash table is unchanged.
**
** If the "data" parameter to this function is NULL, then the
** element corresponding to "key" is removed from the hash table.
*/
void *sqliteHashInsert(Hash *pH, void *pKey, int nKey, void *data){
  int hraw;             /* Raw hash value of the key */
  int h;                /* the hash of the key modulo hash table size */

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle INSERT statements in SQLite.
**
** $Id: insert.c,v 1.32 2002/01/06 17:07:40 drh Exp $
*/
#include "sqliteInt.h"

/*
** This routine is call to handle SQL of the following forms:
**
**    insert into TABLE (IDLIST) values(EXPRLIST)

           " has no column named ", pColumn->a[i].zName, 0);
        pParse->nErr++;
        goto insert_cleanup;
      }
    }
  }

  /* If there is no IDLIST term but the table has an integer primary
  ** key, the set the keyColumn variable to the primary key column index
  ** in the original table definition.
  */
  if( pColumn==0 ){
    keyColumn = pTab->iPKey;
  }

  /* If there are indices, we'll need the new record number again, so make
  ** a copy.
  */
  if( pTab->pIndex ){
    sqliteVdbeAddOp(v, OP_Dup, 0, 0);
  }

  /* Push onto the stack, data for all columns of the new entry, beginning
  ** with the first column.
  */
  for(i=0; i<pTab->nCol; i++){
    if( i==pTab->iPKey ){
      /* The value of the INTEGER PRIMARY KEY column is always a NULL.
      ** Whenever this column is read, the record number will be substituted
      ** in its place.  So will fill this column with a NULL to avoid
      ** taking up data space with information that will never be used. */
      sqliteVdbeAddOp(v, OP_String, 0, 0);
      continue;
    }
    if( pColumn==0 ){
      j = i;
    }else{
      for(j=0; j<pColumn->nId; j++){

**
*************************************************************************
** Main file for the SQLite library.  The routines in this file
** implement the programmer interface to the library.  Routines in
** other files are for internal use by SQLite and should not be
** accessed by users of the library.
**
** $Id: main.c,v 1.53 2002/01/06 17:07:40 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"

/*
** This is the callback routine for the code that initializes the
** database.  See sqliteInit() below for additional information.

        sParse.db = db;
        sParse.initFlag = 1;
        sParse.newTnum = atoi(argv[2]);
        sqliteRunParser(&sParse, argv[3], 0);
      }else{
        /* If the SQL column is blank it means this is an index that
        ** was created to be the PRIMARY KEY or to fulfill a UNIQUE
        ** constraint for a CREATE TABLE.  The index should have already
        ** been created when we processed the CREATE TABLE.  All we have
        ** to do here is record the root page number for that index.
        */
        Index *pIndex = sqliteFindIndex(db, argv[1]);
        if( pIndex==0 || pIndex->tnum!=0 ){
          nErr++;
        }else{
          pIndex->tnum = atoi(argv[2]);
        }

     "  name text,\n"
     "  tbl_name text,\n"
     "  rootpage integer,\n"
     "  sql text\n"
     ")"
  ;

  /* The following VDBE program is used to initialize the internal
  ** structure holding the tables and indexes of the database.
  ** The database contains a special table named "sqlite_master"
  ** defined as follows:
  **
  **    CREATE TABLE sqlite_master (
  **        type       text,    --  Either "table" or "index" or "meta"
  **        name       text,    --  Name of table or index

  if( rc==SQLITE_OK && db->nTable==0 ){
    db->file_format = FILE_FORMAT;
  }
  if( rc==SQLITE_OK && db->file_format>FILE_FORMAT ){
    sqliteSetString(pzErrMsg, "unsupported file format", 0);
    rc = SQLITE_ERROR;
  }

  /* The schema for the SQLITE_MASTER table is not stored in the
  ** database itself.  We have to invoke the callback one extra
  ** time to get it to process the SQLITE_MASTER table defintion.
  */
  if( rc==SQLITE_OK ){
    Table *pTab;
    char *azArg[6];
    azArg[0] = "table";
    azArg[1] = MASTER_NAME;
    azArg[2] = "2";
    azArg[3] = master_schema;

  db->nextRowid = sqliteRandomInteger();
  
  /* Open the backend database driver */
  rc = sqliteBtreeOpen(zFilename, mode, MAX_PAGES, &db->pBe);
  if( rc!=SQLITE_OK ){
    switch( rc ){
      default: {

        sqliteSetString(pzErrMsg, "unable to open database: ", zFilename, 0);

      }
    }
    sqliteFree(db);
    sqliteStrRealloc(pzErrMsg);
    return 0;
  }

  /* Attempt to read the schema */
  rc = sqliteInit(db, pzErrMsg);
  if( sqlite_malloc_failed ){
    sqlite_close(db);
    goto no_mem_on_open;
  }else if( rc!=SQLITE_OK && rc!=SQLITE_BUSY ){
    sqlite_close(db);
    sqliteStrRealloc(pzErrMsg);
    return 0;
  }else if( pzErrMsg ){
    sqliteFree(*pzErrMsg);
    *pzErrMsg = 0;
  }
  return db;

no_mem_on_open:
  sqliteSetString(pzErrMsg, "out of memory", 0);
  sqliteStrRealloc(pzErrMsg);
  return 0;
}

/*
** Erase all schema information from the schema hash table.  Except
** tables that are created using CREATE TEMPORARY TABLE are preserved
** if the preserveTemps flag is true.
**
** The database schema is normally read in once when the database
** is first opened and stored in a hash table in the sqlite structure.
** This routine erases the stored schema.  This erasure occurs because
** either the database is being closed or because some other process
** changed the schema and this process needs to reread it.
*/

** The pager is used to access a database disk file.  It implements
** atomic commit and rollback through the use of a journal file that
** is separate from the database file.  The pager also implements file
** locking to prevent two processes from writing the same database
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.35 2002/01/06 17:07:40 drh Exp $
*/
#include "sqliteInt.h"
#include "pager.h"
#include "os.h"
#include <assert.h>
#include <string.h>

  if( pPager->dbSize<pPg->pgno ){
    pPager->dbSize = pPg->pgno;
  }
  return rc;
}

/*
** Return TRUE if the page given in the argument was previously passed
** to sqlitepager_write().  In other words, return TRUE if it is ok
** to change the content of the page.
*/
int sqlitepager_iswriteable(void *pData){
  PgHdr *pPg = DATA_TO_PGHDR(pData);
  return pPg->dirty;
}

**
*************************************************************************
** This file contains SQLite's grammar for SQL.  Process this file
** using the lemon parser generator to generate C code that runs
** the parser.  Lemon will also generate a header file containing
** numeric codes for all of the tokens.
**
** @(#) $Id: parse.y,v 1.42 2002/01/06 17:07:40 drh Exp $
*/
%token_prefix TK_
%token_type {Token}
%default_type {Token}
%extra_argument {Parse *pParse}
%syntax_error {
  sqliteSetString(&pParse->zErrMsg,"syntax error",0);

id(A) ::= BEGIN(X).      {A = X;}
id(A) ::= END(X).        {A = X;}
id(A) ::= PRAGMA(X).     {A = X;}
id(A) ::= CLUSTER(X).    {A = X;}
id(A) ::= ID(X).         {A = X;}
id(A) ::= TEMP(X).       {A = X;}
id(A) ::= OFFSET(X).     {A = X;}
id(A) ::= KEY(X).        {A = X;}

// And "ids" is an identifer-or-string.
//
%type ids {Token}
ids(A) ::= id(X).        {A = X;}
ids(A) ::= STRING(X).    {A = X;}

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains code to implement the "sqlite" command line
** utility for accessing SQLite databases.
**
** $Id: shell.c,v 1.41 2002/01/06 17:07:40 drh Exp $
*/
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "sqlite.h"
#include <ctype.h>
#ifdef OS_UNIX

  return zLine;
}

/*
** Retrieve a single line of input text.  "isatty" is true if text
** is coming from a terminal.  In that case, we issue a prompt and
** attempt to use "readline" for command-line editing.  If "isatty"
** is false, use "getline" instead of "readline" and issue no prompt.
**
** zPrior is a string of prior text retrieved.  If not the empty
** string, then issue a continuation prompt.
*/
static char *one_input_line(const char *zPrior, FILE *in){
  char *zPrompt;
  char *zResult;

/*
** 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.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.75 2002/01/06 17:07:40 drh Exp $
*/
#include "sqlite.h"
#include "hash.h"
#include "vdbe.h"
#include "parse.h"
#include "btree.h"
#include <stdio.h>

*/
#ifdef MEMORY_DEBUG
extern int sqlite_nMalloc;       /* Number of sqliteMalloc() calls */
extern int sqlite_nFree;         /* Number of sqliteFree() calls */
extern int sqlite_iMallocFail;   /* Fail sqliteMalloc() after this many calls */
#endif








/*
** Name of the master database table.  The master database table
** is a special table that holds the names and attributes of all
** user tables and indices.
*/
#define MASTER_NAME   "sqlite_master"

** type to the other occurs as necessary.
** 
** Most of the code in this file is taken up by the sqliteVdbeExec()
** function which does the work of interpreting a VDBE program.
** But other routines are also provided to help in building up
** a program instruction by instruction.
**
** $Id: vdbe.c,v 1.105 2002/01/06 17:07:41 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** The following global variable is incremented every time a cursor
** moves, either by the OP_MoveTo or the OP_Next opcode.  The test

*/
void sqliteVdbeCompressSpace(Vdbe *p, int addr){
  char *z;
  int i, j;
  Op *pOp;
  if( p->aOp==0 || addr<0 || addr>=p->nOp ) return;
  pOp = &p->aOp[addr];
  if( pOp->p3type==P3_POINTER ){
    return;
  }
  if( pOp->p3type!=P3_DYNAMIC ){
    pOp->p3 = sqliteStrDup(pOp->p3);
    pOp->p3type = P3_DYNAMIC;


  }
  z = pOp->p3;
  if( z==0 ) return;
  i = j = 0;
  while( isspace(z[i]) ){ i++; }
  while( z[i] ){
    if( isspace(z[i]) ){
      z[j++] = ' ';
      while( isspace(z[++i]) ){}
    }else{
      z[j++] = z[i++];
    }
  }
  while( j>0 && isspace(z[j-1]) ){ j--; }
  z[j] = 0;


}

/*
** Reset an Agg structure.  Delete all its contents.
*/
static void AggReset(Agg *pAgg){
  int i;

  if( xCallback==0 ) return 0;
  azValue[0] = zAddr;
  azValue[2] = zP1;
  azValue[3] = zP2;
  azValue[5] = 0;
  rc = SQLITE_OK;

  for(i=0; rc==SQLITE_OK && i<p->nOp; i++){
    if( p->db->flags & SQLITE_Interrupt ){
      p->db->flags &= ~SQLITE_Interrupt;
      sqliteSetString(pzErrMsg, "interrupted", 0);
      rc = SQLITE_INTERRUPT;
      break;
    }

/*
** Execute the program in the VDBE.
**
** If an error occurs, an error message is written to memory obtained
** from sqliteMalloc() and *pzErrMsg is made to point to that memory.
** The return parameter is the number of errors.
**
** If the callback ever returns non-zero, then the program exits
** immediately.  There will be no error message but the function
** does return SQLITE_ABORT.
**
** A memory allocation error causes this routine to return SQLITE_NOMEM
** and abandon furture processing.
**
** Other fatal errors return SQLITE_ERROR.
**
** If a database file could not be opened because it is locked by

  rc = SQLITE_OK;
#ifdef MEMORY_DEBUG
  if( access("vdbe_trace",0)==0 ){
    p->trace = stdout;
  }
#endif

  if( sqlite_malloc_failed ) goto no_mem;
  for(pc=0; !sqlite_malloc_failed && rc==SQLITE_OK && pc<p->nOp
             VERIFY(&& pc>=0); pc++){
    pOp = &p->aOp[pc];

    /* Interrupt processing if requested.
    */

**    May you share freely, never taking more than you give.
**
*************************************************************************
** This module contains C code that generates VDBE code used to process
** the WHERE clause of SQL statements.  Also found here are subroutines
** to generate VDBE code to evaluate expressions.
**
** $Id: where.c,v 1.31 2002/01/06 17:07:41 drh Exp $
*/
#include "sqliteInt.h"

/*
** The query generator uses an array of instances of this structure to
** help it analyze the subexpressions of the WHERE clause.  Each WHERE
** clause subexpression is separated from the others by an AND operator.

      sqliteVdbeAddOp(v, OP_Rewind, base+idx, brk);
      start = sqliteVdbeCurrentAddr(v);
      pLevel->op = OP_Next;
      pLevel->p1 = base+idx;
      pLevel->p2 = start;
      haveKey = 0;
    }else{
      /* Case 5: The contraint on the right-most index field is
      **         an inequality.
      */
      int score = pLevel->score;
      int nEqColumn = score/4;
      int start;
      int leFlag, geFlag;
      int testOp;