SQLite

Lemon also implements features that can be used
to eliminate resource leaks, making is suitable for use
in long-running programs such as graphical user interfaces
or embedded controllers.</p>

<p>This document is an introduction to the Lemon
parser generator.</p>

<h2>Security Note</h2>

<p>The language parser code created by Lemon is very robust and
is well-suited for use in internet-facing applications that need to
safely process maliciously crafted inputs.

<p>The "lemon.exe" command-line tool itself works great when given a valid
input grammar file and almost always gives helpful
error messages for malformed inputs.  However,  it is possible for
a malicious user to craft a grammar file that will cause 
lemon.exe to crash.
We do not see this as a problem, as lemon.exe is not intended to be used
with hostile inputs.
To summarize:</p>

<ul>
<li>Parser code generated by lemon &rarr; Robust and secure
<li>The "lemon.exe" command line tool itself &rarr; Not so much
</ul>

<h2>Theory of Operation</h2>

<p>The main goal of Lemon is to translate a context free grammar (CFG)
for a particular language into C code that implements a parser for
that language.
The program has two inputs:

** Integers 20 through 29.
**
** HOW IT WORKS
**
** The generate_series "function" is really a virtual table with the
** following schema:
**
**     CREATE TABLE generate_series(
**       value,
**       start HIDDEN,
**       stop HIDDEN,
**       step HIDDEN
**     );
**
** Function arguments in queries against this virtual table are translated

    pParse->nErr++;
    goto begin_table_error;
  }
  pTable->zName = zName;
  pTable->iPKey = -1;
  pTable->pSchema = db->aDb[iDb].pSchema;
  pTable->nTabRef = 1;
#ifdef SQLITE_DEFAULT_ROWEST
  pTable->nRowLogEst = sqlite3LogEst(SQLITE_DEFAULT_ROWEST);
#else
  pTable->nRowLogEst = 200; assert( 200==sqlite3LogEst(1048576) );
#endif
  assert( pParse->pNewTable==0 );
  pParse->pNewTable = pTable;

  /* If this is the magic sqlite_sequence table used by autoincrement,
  ** then record a pointer to this table in the main database structure
  ** so that INSERT can find the table easily.
  */

        iKey = ++pParse->nMem;
        nKey = 0;   /* Zero tells OP_Found to use a composite key */
        sqlite3VdbeAddOp4(v, OP_MakeRecord, iPk, nPk, iKey,
            sqlite3IndexAffinityStr(pParse->db, pPk), nPk);
        sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iEphCur, iKey, iPk, nPk);
      }else{
        /* Add the rowid of the row to be deleted to the RowSet */
        nKey = 1;  /* OP_DeferredSeek always uses a single rowid */
        sqlite3VdbeAddOp2(v, OP_RowSetAdd, iRowSet, iKey);
      }
    }
  
    /* If this DELETE cannot use the ONEPASS strategy, this is the 
    ** end of the WHERE loop */
    if( eOnePass!=ONEPASS_OFF ){

  int tmask;                  /* Mask of trigger times */
#endif

  db = pParse->db;
  if( pParse->nErr || db->mallocFailed ){
    goto insert_cleanup;
  }
  dest.iSDParm = 0;  /* Suppress a harmless compiler warning */

  /* If the Select object is really just a simple VALUES() list with a
  ** single row (the common case) then keep that one row of values
  ** and discard the other (unused) parts of the pSelect object
  */
  if( pSelect && (pSelect->selFlags & SF_Values)!=0 && pSelect->pPrior==0 ){
    pList = pSelect->pEList;

** lower 30 bits of a 32-bit signed integer.
*/
static int strlen30(const char *z){
  const char *z2 = z;
  while( *z2 ){ z2++; }
  return 0x3fffffff & (int)(z2 - z);
}

/*
** Return the length of a string in characters.  Multibyte UTF8 characters
** count as a single character.
*/
static int strlenChar(const char *z){
  int n = 0;
  while( *z ){
    if( (0xc0&*(z++))!=0x80 ) n++;
  }
  return n;
}

/*
** This routine reads a line of text from FILE in, stores
** the text in memory obtained from malloc() and returns a pointer
** to the text.  NULL is returned at end of file, or if malloc()
** fails.
**

          int w, n;
          if( i<ArraySize(p->colWidth) ){
            w = colWidth[i];
          }else{
            w = 0;
          }
          if( w==0 ){
            w = strlenChar(azCol[i] ? azCol[i] : "");
            if( w<10 ) w = 10;
            n = strlenChar(azArg && azArg[i] ? azArg[i] : p->nullValue);
            if( w<n ) w = n;
          }
          if( i<ArraySize(p->actualWidth) ){
            p->actualWidth[i] = w;
          }
          if( showHdr ){
            utf8_width_print(p->out, w, azCol[i]);

      for(i=0; i<nArg; i++){
        int w;
        if( i<ArraySize(p->actualWidth) ){
           w = p->actualWidth[i];
        }else{
           w = 10;
        }
        if( p->cMode==MODE_Explain && azArg[i] && strlenChar(azArg[i])>w ){
          w = strlenChar(azArg[i]);
        }
        if( i==1 && p->aiIndent && p->pStmt ){
          if( p->iIndent<p->nIndent ){
            utf8_printf(p->out, "%*.s", p->aiIndent[p->iIndent], "");
          }
          p->iIndent++;
        }

      for(i=nPrefix; zQuery[i]; i++){
        if( zQuery[i]==aWild[0] || zQuery[i]==aWild[1] ) break;
        if( zQuery[i]=='/' ) nDir = i;
      }
      zDir = zQuery;
    }
  }
  if( nDir==0 ) nDir = 1;

  sqlite3_bind_text(pCsr->pStmt, 1, zDir, nDir, SQLITE_TRANSIENT);
  sqlite3_bind_text(pCsr->pStmt, 2, zRoot, nRoot, SQLITE_TRANSIENT);
  sqlite3_bind_text(pCsr->pStmt, 3, zPrefix, nPrefix, SQLITE_TRANSIENT);

#if SQLITE_OS_WIN
  sqlite3_free(zPrefix);

  u32 avail;         /* Number of bytes of available data */
  u32 t;             /* A type code from the record header */
  Mem *pReg;         /* PseudoTable input register */

  pC = p->apCsr[pOp->p1];
  p2 = pOp->p2;

  /* If the cursor cache is stale (meaning it is not currently point at
  ** the correct row) then bring it up-to-date by doing the necessary 
  ** B-Tree seek. */
  rc = sqlite3VdbeCursorMoveto(&pC, &p2);
  if( rc ) goto abort_due_to_error;

  assert( pOp->p3>0 && pOp->p3<=(p->nMem+1 - p->nCursor) );
  pDest = &aMem[pOp->p3];
  memAboutToChange(p, pDest);
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );

  }
  assert( pC->deferredMoveto==0 );
  pC->cacheStatus = CACHE_STALE;
  pC->seekResult = 0;
  break;
}

/* Opcode: DeferredSeek P1 * P3 P4 *
** Synopsis: Move P3 to P1.rowid if needed
**
** P1 is an open index cursor and P3 is a cursor on the corresponding
** table.  This opcode does a deferred seek of the P3 table cursor
** to the row that corresponds to the current row of P1.
**
** This is a deferred seek.  Nothing actually happens until
** the cursor is used to read a record.  That way, if no reads

**
** Write into register P2 an integer which is the last entry in the record at
** the end of the index key pointed to by cursor P1.  This integer should be
** the rowid of the table entry to which this index entry points.
**
** See also: Rowid, MakeRecord.
*/
case OP_DeferredSeek:
case OP_IdxRowid: {           /* out2 */
  VdbeCursor *pC;             /* The P1 index cursor */
  VdbeCursor *pTabCur;        /* The P2 table cursor (OP_DeferredSeek only) */
  i64 rowid;                  /* Rowid that P1 current points to */

  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  assert( pC->eCurType==CURTYPE_BTREE );
  assert( pC->uc.pCursor!=0 );
  assert( pC->isTable==0 );

  if( !pC->nullRow ){
    rowid = 0;  /* Not needed.  Only used to silence a warning. */
    rc = sqlite3VdbeIdxRowid(db, pC->uc.pCursor, &rowid);
    if( rc!=SQLITE_OK ){
      goto abort_due_to_error;
    }
    if( pOp->opcode==OP_DeferredSeek ){
      assert( pOp->p3>=0 && pOp->p3<p->nCursor );
      pTabCur = p->apCsr[pOp->p3];
      assert( pTabCur!=0 );
      assert( pTabCur->eCurType==CURTYPE_BTREE );
      assert( pTabCur->uc.pCursor!=0 );
      assert( pTabCur->isTable );
      pTabCur->nullRow = 0;

** Cursor iCur is open on an intkey b-tree (a table). Register iRowid contains
** a rowid value just read from cursor iIdxCur, open on index pIdx. This
** function generates code to do a deferred seek of cursor iCur to the 
** rowid stored in register iRowid.
**
** Normally, this is just:
**
**   OP_DeferredSeek $iCur $iRowid
**
** However, if the scan currently being coded is a branch of an OR-loop and
** the statement currently being coded is a SELECT, then P3 of OP_DeferredSeek
** is set to iIdxCur and P4 is set to point to an array of integers
** containing one entry for each column of the table cursor iCur is open 
** on. For each table column, if the column is the i'th column of the 
** index, then the corresponding array entry is set to (i+1). If the column
** does not appear in the index at all, the array entry is set to 0.
*/
static void codeDeferredSeek(
  WhereInfo *pWInfo,              /* Where clause context */
  Index *pIdx,                    /* Index scan is using */
  int iCur,                       /* Cursor for IPK b-tree */
  int iIdxCur                     /* Index cursor */
){
  Parse *pParse = pWInfo->pParse; /* Parse context */
  Vdbe *v = pParse->pVdbe;        /* Vdbe to generate code within */

  assert( iIdxCur>0 );
  assert( pIdx->aiColumn[pIdx->nColumn-1]==-1 );
  
  sqlite3VdbeAddOp3(v, OP_DeferredSeek, iIdxCur, 0, iCur);
  if( (pWInfo->wctrlFlags & WHERE_OR_SUBCLAUSE)
   && DbMaskAllZero(sqlite3ParseToplevel(pParse)->writeMask)
  ){
    int i;
    Table *pTab = pIdx->pTable;
    int *ai = (int*)sqlite3DbMallocZero(pParse->db, sizeof(int)*(pTab->nCol+1));
    if( ai ){

"\n"
"        Generate a new test database file named DBFILE containing N\n"
"        BLOBs each of size M bytes.  The page size of the new database\n"
"        file will be X.  Additional options:\n"
"\n"
"           --variance V           Randomly vary M by plus or minus V\n"
"\n"
"   kvtest export DBFILE DIRECTORY [--tree]\n"
"\n"
"        Export all the blobs in the kv table of DBFILE into separate\n"
"        files in DIRECTORY.  DIRECTORY is created if it does not previously\n"
"        exist.  If the --tree option is used, then the blobs are written\n"
"        into a hierarchy of directories, using names like 00/00/00,\n"
"        00/00/01, 00/00/02, and so forth.  Without the --tree option, all\n"
"        files are in the top-level directory with names like 000000, 000001,\n"
"        000002, and so forth.\n"
"\n"
"   kvtest stat DBFILE [options]\n"
"\n"
"        Display summary information about DBFILE.  Options:\n"
"\n"
"           --vacuum               Run VACUUM on the database file\n"
"\n"
"   kvtest run DBFILE [options]\n"
"\n"
"        Run a performance test.  DBFILE can be either the name of a\n"
"        database or a directory containing sample files.  Options:\n"
"\n"
"           --asc                  Read blobs in ascending order\n"
"           --blob-api             Use the BLOB API\n"
"           --cache-size N         Database cache size\n"
"           --count N              Read N blobs\n"
"           --desc                 Read blobs in descending order\n"
"           --fsync                Synchronous file writes\n"
"           --integrity-check      Run \"PRAGMA integrity_check\" after test\n"
"           --max-id N             Maximum blob key to use\n"
"           --mmap N               Mmap as much as N bytes of DBFILE\n"
"           --multitrans           Each read or write in its own transaction\n"
"           --nocheckpoint         Omit the checkpoint on WAL mode writes\n"
"           --nosync               Set \"PRAGMA synchronous=OFF\"\n"
"           --jmode MODE           Set MODE journal mode prior to starting\n"
"           --random               Read blobs in a random order\n"
"           --start N              Start reading with this blob key\n"
"           --stats                Output operating stats before exiting\n"
"           --update               Do an overwrite test\n"
;

/* Reference resources used */
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <assert.h>
#include <string.h>
#include "sqlite3.h"

#ifndef _WIN32
# include <unistd.h>
#else
  /* Provide Windows equivalent for the needed parts of unistd.h */
# include <direct.h>
# include <io.h>
# define R_OK 2
# define S_ISREG(m) (((m) & S_IFMT) == S_IFREG)
# define S_ISDIR(m) (((m) & S_IFMT) == S_IFDIR)
# define access _access
#endif

#include <stdint.h>

/*
** The following macros are used to cast pointers to integers and
** integers to pointers.  The way you do this varies from one compiler
** to the next, so we have developed the following set of #if statements
** to generate appropriate macros for a wide range of compilers.
**
** The correct "ANSI" way to do this is to use the intptr_t type.
** Unfortunately, that typedef is not available on all compilers, or
** if it is available, it requires an #include of specific headers
** that vary from one machine to the next.
**
** Ticket #3860:  The llvm-gcc-4.2 compiler from Apple chokes on
** the ((void*)&((char*)0)[X]) construct.  But MSVC chokes on ((void*)(X)).
** So we have to define the macros in different ways depending on the
** compiler.
*/
#if defined(__PTRDIFF_TYPE__)  /* This case should work for GCC */
# define SQLITE_INT_TO_PTR(X)  ((void*)(__PTRDIFF_TYPE__)(X))
# define SQLITE_PTR_TO_INT(X)  ((sqlite3_int64)(__PTRDIFF_TYPE__)(X))
#else
# define SQLITE_INT_TO_PTR(X)  ((void*)(intptr_t)(X))
# define SQLITE_PTR_TO_INT(X)  ((sqlite3_int64)(intptr_t)(X))
#endif

/*
** Show thqe help text and quit.
*/
static void showHelp(void){
  fprintf(stdout, "%s", zHelp);
  exit(1);

  return isNeg? -v : v;
}


/*
** Check the filesystem object zPath.  Determine what it is:
**
**    PATH_DIR     A single directory holding many files
**    PATH_TREE    A directory hierarchy with files at the leaves
**    PATH_DB      An SQLite database
**    PATH_NEXIST  Does not exist
**    PATH_OTHER   Something else
**
** PATH_DIR means all of the separate files are grouped together
** into a single directory with names like 000000, 000001, 000002, and
** so forth.  PATH_TREE means there is a hierarchy of directories so
** that no single directory has too many entries.  The files have names
** like 00/00/00, 00/00/01, 00/00/02 and so forth.  The decision between
** PATH_DIR and PATH_TREE is determined by the presence of a subdirectory
** named "00" at the top-level.
*/
#define PATH_DIR     1
#define PATH_TREE    2
#define PATH_DB      3
#define PATH_NEXIST  0
#define PATH_OTHER   99
static int pathType(const char *zPath){
  struct stat x;
  int rc;
  if( access(zPath,R_OK) ) return PATH_NEXIST;
  memset(&x, 0, sizeof(x));
  rc = stat(zPath, &x);
  if( rc<0 ) return PATH_OTHER;
  if( S_ISDIR(x.st_mode) ){
    char *zLayer1 = sqlite3_mprintf("%s/00", zPath);
    memset(&x, 0, sizeof(x));
    rc = stat(zLayer1, &x);
    sqlite3_free(zLayer1);
    if( rc<0 ) return PATH_DIR;
    if( S_ISDIR(x.st_mode) ) return PATH_TREE;
    return PATH_DIR;
  }
  if( (x.st_size%512)==0 ) return PATH_DB;
  return PATH_OTHER;
}

/*
** Return the size of a file in bytes.  Or return -1 if the
** named object is not a regular file or does not exist.

*/
static int statMain(int argc, char **argv){
  char *zDb;
  int i, rc;
  sqlite3 *db;
  char *zSql;
  sqlite3_stmt *pStmt;
  int doVacuum = 0;

  assert( strcmp(argv[1],"stat")==0 );
  assert( argc>=3 );
  zDb = argv[2];
  for(i=3; i<argc; i++){
    char *z = argv[i];
    if( z[0]!='-' ) fatalError("unknown argument: \"%s\"", z);
    if( z[1]=='-' ) z++;
    if( strcmp(z, "-vacuum")==0 ){
      doVacuum = 1;
      continue;
    }
    fatalError("unknown option: \"%s\"", argv[i]);
  }
  rc = sqlite3_open(zDb, &db);
  if( rc ){
    fatalError("cannot open database \"%s\": %s", zDb, sqlite3_errmsg(db));
  }
  if( doVacuum ){
    printf("Vacuuming...."); fflush(stdout);
    sqlite3_exec(db, "VACUUM", 0, 0, 0);
    printf("       done\n");
  }
  zSql = sqlite3_mprintf(
    "SELECT count(*), min(length(v)), max(length(v)), avg(length(v))"
    "  FROM kv"
  );
  rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0);
  if( rc ) fatalError("cannot prepare SQL [%s]: %s", zSql, sqlite3_errmsg(db));
  sqlite3_free(zSql);

  zSql = sqlite3_mprintf("PRAGMA page_count");
  rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0);
  if( rc ) fatalError("cannot prepare SQL [%s]: %s", zSql, sqlite3_errmsg(db));
  sqlite3_free(zSql);
  if( sqlite3_step(pStmt)==SQLITE_ROW ){
    printf("Page-count:         %8d\n", sqlite3_column_int(pStmt, 0));
  }
  sqlite3_finalize(pStmt);
  zSql = sqlite3_mprintf("PRAGMA freelist_count");
  rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0);
  if( rc ) fatalError("cannot prepare SQL [%s]: %s", zSql, sqlite3_errmsg(db));
  sqlite3_free(zSql);
  if( sqlite3_step(pStmt)==SQLITE_ROW ){
    printf("Freelist-count:     %8d\n", sqlite3_column_int(pStmt, 0));
  }
  sqlite3_finalize(pStmt);
  rc = sqlite3_prepare_v2(db, "PRAGMA integrity_check(10)", -1, &pStmt, 0);
  if( rc ) fatalError("cannot prepare integrity check: %s", sqlite3_errmsg(db));
  while( sqlite3_step(pStmt)==SQLITE_ROW ){
    printf("Integrity-check:    %s\n", sqlite3_column_text(pStmt, 0));
  }
  sqlite3_finalize(pStmt);
  sqlite3_close(db);
  return 0;
}

/*
**      remember(V,PTR)
**
** Return the integer value V.  Also save the value of V in a
** C-language variable whose address is PTR.
*/
static void rememberFunc(
  sqlite3_context *pCtx,
  int argc,
  sqlite3_value **argv
){
  sqlite3_int64 v;

  sqlite3_int64 ptr;

  assert( argc==2 );
  v = sqlite3_value_int64(argv[0]);



  ptr = sqlite3_value_int64(argv[1]);

  *(sqlite3_int64*)SQLITE_INT_TO_PTR(ptr) = v;

  sqlite3_result_int64(pCtx, v);
}

/*
** Make sure a directory named zDir exists.
*/
static void kvtest_mkdir(const char *zDir){
#if defined(_WIN32)
  (void)mkdir(zDir);
#else
  (void)mkdir(zDir, 0755);
#endif
}

/*
** Export the kv table to individual files in the filesystem
*/
static int exportMain(int argc, char **argv){
  char *zDb;
  char *zDir;
  sqlite3 *db;
  sqlite3_stmt *pStmt;
  int rc;
  int ePathType;
  int nFN;
  char *zFN;
  char *zTail;
  size_t nWrote;
  int i;

  assert( strcmp(argv[1],"export")==0 );
  assert( argc>=3 );
  if( argc<4 ) fatalError("Usage: kvtest export DATABASE DIRECTORY [OPTIONS]");
  zDb = argv[2];

  zDir = argv[3];
  kvtest_mkdir(zDir);
  for(i=4; i<argc; i++){
    const char *z = argv[i];
    if( z[0]=='-' && z[1]=='-' ) z++;
    if( strcmp(z,"-tree")==0 ){
      zFN = sqlite3_mprintf("%s/00", zDir);
      kvtest_mkdir(zFN);
      sqlite3_free(zFN);
      continue;
    }
    fatalError("unknown argument: \"%s\"\n", argv[i]);
  }
  ePathType = pathType(zDir);
  if( ePathType!=PATH_DIR && ePathType!=PATH_TREE ){
    fatalError("object \"%s\" is not a directory", zDir);
  }
  rc = sqlite3_open(zDb, &db);
  if( rc ){
    fatalError("cannot open database \"%s\": %s", zDb, sqlite3_errmsg(db));
  }
  rc = sqlite3_prepare_v2(db, "SELECT k, v FROM kv ORDER BY k", -1, &pStmt, 0);
  if( rc ){
    fatalError("prepare_v2 failed: %s\n", sqlite3_errmsg(db));
  }
  nFN = (int)strlen(zDir);
  zFN = sqlite3_mprintf("%s/00/00/00.extra---------------------", zDir);
  if( zFN==0 ){
    fatalError("malloc failed\n");
  }
  zTail = zFN + nFN + 1;
  while( sqlite3_step(pStmt)==SQLITE_ROW ){
    int iKey = sqlite3_column_int(pStmt, 0);
    sqlite3_int64 nData = sqlite3_column_bytes(pStmt, 1);
    const void *pData = sqlite3_column_blob(pStmt, 1);
    FILE *out;
    if( ePathType==PATH_DIR ){
      sqlite3_snprintf(20, zTail, "%06d", iKey);
    }else{
      sqlite3_snprintf(20, zTail, "%02d", iKey/10000);
      kvtest_mkdir(zFN);
      sqlite3_snprintf(20, zTail, "%02d/%02d", iKey/10000, (iKey/100)%100);
      kvtest_mkdir(zFN);
      sqlite3_snprintf(20, zTail, "%02d/%02d/%02d",
                       iKey/10000, (iKey/100)%100, iKey%100);
    }
    out = fopen(zFN, "wb");      
    nWrote = fwrite(pData, 1, nData, out);
    fclose(out);
    printf("\r%s   ", zTail); fflush(stdout);
    if( nWrote!=nData ){
      fatalError("Wrote only %d of %d bytes to %s\n",
                  (int)nWrote, nData, zFN);
    }
  }
  sqlite3_finalize(pStmt);
  sqlite3_close(db);
  sqlite3_free(zFN);
  printf("\n");
  return 0;
}

/*
** Read the content of file zName into memory obtained from sqlite3_malloc64()
** and return a pointer to the buffer. The caller is responsible for freeing 
** the memory. 
**
** If parameter pnByte is not NULL, (*pnByte) is set to the number of bytes
** read.
**
** For convenience, a nul-terminator byte is always appended to the data read
** from the file before the buffer is returned. This byte is not included in
** the final value of (*pnByte), if applicable.
**
** NULL is returned if any error is encountered. The final value of *pnByte
** is undefined in this case.
*/
static unsigned char *readFile(const char *zName, sqlite3_int64 *pnByte){
  FILE *in;               /* FILE from which to read content of zName */
  sqlite3_int64 nIn;      /* Size of zName in bytes */
  size_t nRead;           /* Number of bytes actually read */
  unsigned char *pBuf;    /* Content read from disk */

  nIn = fileSize(zName);
  if( nIn<0 ) return 0;
  in = fopen(zName, "rb");
  if( in==0 ) return 0;
  pBuf = sqlite3_malloc64( nIn );
  if( pBuf==0 ) return 0;
  nRead = fread(pBuf, (size_t)nIn, 1, in);
  fclose(in);
  if( nRead!=1 ){
    sqlite3_free(pBuf);
    return 0;
  }
  if( pnByte ) *pnByte = nIn;
  return pBuf;
}

/*
** Overwrite a file with randomness.  Do not change the size of the
** file.
*/
static void updateFile(const char *zName, sqlite3_int64 *pnByte, int doFsync){
  FILE *out;              /* FILE from which to read content of zName */
  sqlite3_int64 sz;       /* Size of zName in bytes */
  size_t nWritten;        /* Number of bytes actually read */
  unsigned char *pBuf;    /* Content to store on disk */
  const char *zMode = "wb";   /* Mode for fopen() */

  sz = fileSize(zName);
  if( sz<0 ){
    fatalError("No such file: \"%s\"", zName);
  }
  *pnByte = sz;
  if( sz==0 ) return;
  pBuf = sqlite3_malloc64( sz );
  if( pBuf==0 ){
    fatalError("Cannot allocate %lld bytes\n", sz);
  }
  sqlite3_randomness((int)sz, pBuf); 
#if defined(_WIN32)
  if( doFsync ) zMode = "wbc";
#endif
  out = fopen(zName, zMode);
  if( out==0 ){
    fatalError("Cannot open \"%s\" for writing\n", zName);
  }
  nWritten = fwrite(pBuf, 1, (size_t)sz, out);
  if( doFsync ){
#if defined(_WIN32)
    fflush(out);
#else
    fsync(fileno(out));
#endif
  }
  fclose(out);
  if( nWritten!=(size_t)sz ){
    fatalError("Wrote only %d of %d bytes to \"%s\"\n",
               (int)nWritten, (int)sz, zName);
  }
  sqlite3_free(pBuf);
}

/*
** Return the current time in milliseconds since the beginning of
** the Julian epoch.
*/
static sqlite3_int64 timeOfDay(void){
  static sqlite3_vfs *clockVfs = 0;

  int iKey = 1;               /* Next blob key */
  int iMax = 0;               /* Largest allowed key */
  int iPagesize = 0;          /* Database page size */
  int iCache = 1000;          /* Database cache size in kibibytes */
  int bBlobApi = 0;           /* Use the incremental blob I/O API */
  int bStats = 0;             /* Print stats before exiting */
  int eOrder = ORDER_ASC;     /* Access order */
  int isUpdateTest = 0;       /* Do in-place updates rather than reads */
  int doIntegrityCk = 0;      /* Run PRAGMA integrity_check after the test */
  int noSync = 0;             /* Disable synchronous mode */
  int doFsync = 0;            /* Update disk files synchronously */
  int doMultiTrans = 0;       /* Each operation in its own transaction */
  int noCheckpoint = 0;       /* Omit the checkpoint in WAL mode */
  sqlite3 *db = 0;            /* Database connection */
  sqlite3_stmt *pStmt = 0;    /* Prepared statement for SQL access */
  sqlite3_blob *pBlob = 0;    /* Handle for incremental Blob I/O */
  sqlite3_int64 tmStart;      /* Start time */
  sqlite3_int64 tmElapsed;    /* Elapsed time */
  int mmapSize = 0;           /* --mmap N argument */
  sqlite3_int64 nData = 0;    /* Bytes of data */
  sqlite3_int64 nTotal = 0;   /* Total data read */
  unsigned char *pData = 0;   /* Content of the blob */
  sqlite3_int64 nAlloc = 0;   /* Space allocated for pData[] */
  const char *zJMode = 0;     /* Journal mode */
  

  assert( strcmp(argv[1],"run")==0 );
  assert( argc>=3 );
  zDb = argv[2];
  eType = pathType(zDb);
  if( eType==PATH_OTHER ) fatalError("unknown object type: \"%s\"", zDb);
  if( eType==PATH_NEXIST ) fatalError("object does not exist: \"%s\"", zDb);
  for(i=3; i<argc; i++){
    char *z = argv[i];
    if( z[0]!='-' ) fatalError("unknown argument: \"%s\"", z);
    if( z[1]=='-' ) z++;
    if( strcmp(z, "-asc")==0 ){
      eOrder = ORDER_ASC;
      continue;
    }
    if( strcmp(z, "-blob-api")==0 ){
      bBlobApi = 1;
      continue;
    }
    if( strcmp(z, "-cache-size")==0 ){
      if( i==argc-1 ) fatalError("missing argument on \"%s\"", argv[i]);
      iCache = integerValue(argv[++i]);
      continue;
    }
    if( strcmp(z, "-count")==0 ){
      if( i==argc-1 ) fatalError("missing argument on \"%s\"", argv[i]);
      nCount = integerValue(argv[++i]);
      if( nCount<1 ) fatalError("the --count must be positive");
      continue;
    }
    if( strcmp(z, "-desc")==0 ){
      eOrder = ORDER_DESC;
      continue;
    }
    if( strcmp(z, "-fsync")==0 ){
      doFsync = 1;
      continue;
    }
    if( strcmp(z, "-integrity-check")==0 ){
      doIntegrityCk = 1;
      continue;
    }
    if( strcmp(z, "-jmode")==0 ){
      if( i==argc-1 ) fatalError("missing argument on \"%s\"", argv[i]);
      zJMode = argv[++i];
      continue;
    }
    if( strcmp(z, "-mmap")==0 ){
      if( i==argc-1 ) fatalError("missing argument on \"%s\"", argv[i]);
      mmapSize = integerValue(argv[++i]);
      if( nCount<0 ) fatalError("the --mmap must be non-negative");
      continue;
    }
    if( strcmp(z, "-max-id")==0 ){
      if( i==argc-1 ) fatalError("missing argument on \"%s\"", argv[i]);
      iMax = integerValue(argv[++i]);
      continue;
    }
    if( strcmp(z, "-multitrans")==0 ){

      doMultiTrans = 1;

      continue;
    }
    if( strcmp(z, "-nocheckpoint")==0 ){

      noCheckpoint = 1;
      continue;
    }
    if( strcmp(z, "-nosync")==0 ){

      noSync = 1;
      continue;
    }
    if( strcmp(z, "-random")==0 ){
      eOrder = ORDER_RANDOM;
      continue;
    }
    if( strcmp(z, "-start")==0 ){
      if( i==argc-1 ) fatalError("missing argument on \"%s\"", argv[i]);
      iKey = integerValue(argv[++i]);

      if( iKey<1 ) fatalError("the --start must be positive");





      continue;
    }
    if( strcmp(z, "-stats")==0 ){
      bStats = 1;
      continue;
    }
    if( strcmp(z, "-update")==0 ){
      isUpdateTest = 1;
      continue;
    }
    fatalError("unknown option: \"%s\"", argv[i]);
  }
  if( eType==PATH_DB ){
    /* Recover any prior crashes prior to starting the timer */
    sqlite3_open(zDb, &db);
    sqlite3_exec(db, "SELECT rowid FROM sqlite_master LIMIT 1", 0, 0, 0);
    sqlite3_close(db);
    db = 0;
  }
  tmStart = timeOfDay();
  if( eType==PATH_DB ){
    char *zSql;
    rc = sqlite3_open(zDb, &db);
    if( rc ){
      fatalError("cannot open database \"%s\": %s", zDb, sqlite3_errmsg(db));
    }
    zSql = sqlite3_mprintf("PRAGMA mmap_size=%d", mmapSize);
    sqlite3_exec(db, zSql, 0, 0, 0);
    sqlite3_free(zSql);
    zSql = sqlite3_mprintf("PRAGMA cache_size=%d", iCache);
    sqlite3_exec(db, zSql, 0, 0, 0);
    sqlite3_free(zSql);
    if( noSync ){
      sqlite3_exec(db, "PRAGMA synchronous=OFF", 0, 0, 0);
    }
    pStmt = 0;
    sqlite3_prepare_v2(db, "PRAGMA page_size", -1, &pStmt, 0);
    if( sqlite3_step(pStmt)==SQLITE_ROW ){
      iPagesize = sqlite3_column_int(pStmt, 0);
    }
    sqlite3_finalize(pStmt);
    sqlite3_prepare_v2(db, "PRAGMA cache_size", -1, &pStmt, 0);
    if( sqlite3_step(pStmt)==SQLITE_ROW ){
      iCache = sqlite3_column_int(pStmt, 0);
    }else{
      iCache = 0;
    }
    sqlite3_finalize(pStmt);
    pStmt = 0;
    if( zJMode ){
      zSql = sqlite3_mprintf("PRAGMA journal_mode=%Q", zJMode);
      sqlite3_exec(db, zSql, 0, 0, 0);
      sqlite3_free(zSql);
      if( noCheckpoint ){
        sqlite3_exec(db, "PRAGMA wal_autocheckpoint=0", 0, 0, 0);
      }
    }
    sqlite3_prepare_v2(db, "PRAGMA journal_mode", -1, &pStmt, 0);
    if( sqlite3_step(pStmt)==SQLITE_ROW ){
      zJMode = sqlite3_mprintf("%s", sqlite3_column_text(pStmt, 0));
    }else{
      zJMode = "???";
    }
    sqlite3_finalize(pStmt);
    if( iMax<=0 ){
      sqlite3_prepare_v2(db, "SELECT max(k) FROM kv", -1, &pStmt, 0);
      if( sqlite3_step(pStmt)==SQLITE_ROW ){
        iMax = sqlite3_column_int(pStmt, 0);
      }
      sqlite3_finalize(pStmt);
    }
    pStmt = 0;
    if( !doMultiTrans ) sqlite3_exec(db, "BEGIN", 0, 0, 0);
  }
  if( iMax<=0 ) iMax = 1000;
  for(i=0; i<nCount; i++){
    if( eType==PATH_DIR || eType==PATH_TREE ){
      /* CASE 1: Reading or writing blobs out of separate files */
      char *zKey;
      if( eType==PATH_DIR ){
        zKey = sqlite3_mprintf("%s/%06d", zDb, iKey);
      }else{
        zKey = sqlite3_mprintf("%s/%02d/%02d/%02d", zDb, iKey/10000,
                               (iKey/100)%100, iKey%100);
      }
      nData = 0;
      if( isUpdateTest ){
        updateFile(zKey, &nData, doFsync);
      }else{
        pData = readFile(zKey, &nData);
        sqlite3_free(pData);
      }
      sqlite3_free(zKey);
    }else if( bBlobApi ){
      /* CASE 2: Reading from database using the incremental BLOB I/O API */
      if( pBlob==0 ){
        rc = sqlite3_blob_open(db, "main", "kv", "v", iKey,
                               isUpdateTest, &pBlob);
        if( rc ){
          fatalError("could not open sqlite3_blob handle: %s",
                     sqlite3_errmsg(db));
        }
      }else{
        rc = sqlite3_blob_reopen(pBlob, iKey);
      }
      if( rc==SQLITE_OK ){
        nData = sqlite3_blob_bytes(pBlob);
        if( nAlloc<nData+1 ){
          nAlloc = nData+100;
          pData = sqlite3_realloc64(pData, nAlloc);
        }
        if( pData==0 ) fatalError("cannot allocate %d bytes", nData+1);
        if( isUpdateTest ){
          sqlite3_randomness((int)nData, pData);
          rc = sqlite3_blob_write(pBlob, pData, (int)nData, 0);
          if( rc!=SQLITE_OK ){
            fatalError("could not write the blob at %d: %s", iKey,
                      sqlite3_errmsg(db));
          }
        }else{
          rc = sqlite3_blob_read(pBlob, pData, (int)nData, 0);
          if( rc!=SQLITE_OK ){
            fatalError("could not read the blob at %d: %s", iKey,
                      sqlite3_errmsg(db));
          }
        }
      }
    }else{
      /* CASE 3: Reading from database using SQL */
      if( pStmt==0 ){
        if( isUpdateTest ){
          sqlite3_create_function(db, "remember", 2, SQLITE_UTF8, 0,
                                  rememberFunc, 0, 0);

          rc = sqlite3_prepare_v2(db, 
            "UPDATE kv SET v=randomblob(remember(length(v),?2))"
            " WHERE k=?1", -1, &pStmt, 0);
          sqlite3_bind_int64(pStmt, 2, SQLITE_PTR_TO_INT(&nData));
        }else{
          rc = sqlite3_prepare_v2(db, 
                 "SELECT v FROM kv WHERE k=?1", -1, &pStmt, 0);
        }
        if( rc ){
          fatalError("cannot prepare query: %s", sqlite3_errmsg(db));
        }
      }else{
        sqlite3_reset(pStmt);
      }
      sqlite3_bind_int(pStmt, 1, iKey);
      nData = 0;
      rc = sqlite3_step(pStmt);
      if( rc==SQLITE_ROW ){
        nData = sqlite3_column_bytes(pStmt, 0);
        pData = (unsigned char*)sqlite3_column_blob(pStmt, 0);


      }
    }
    if( eOrder==ORDER_ASC ){
      iKey++;
      if( iKey>iMax ) iKey = 1;
    }else if( eOrder==ORDER_DESC ){
      iKey--;
      if( iKey<=0 ) iKey = iMax;
    }else{
      iKey = (randInt()%iMax)+1;
    }
    nTotal += nData;
    if( nData==0 ){ nCount++; nExtra++; }
  }
  if( nAlloc ) sqlite3_free(pData);
  if( pStmt ) sqlite3_finalize(pStmt);
  if( pBlob ) sqlite3_blob_close(pBlob);
  if( bStats ){
    display_stats(db, 0);
  }
  if( db ){
    if( !doMultiTrans ) sqlite3_exec(db, "COMMIT", 0, 0, 0);
    if( !noCheckpoint ){
      sqlite3_close(db);
      db = 0;
    }
  }
  tmElapsed = timeOfDay() - tmStart;
  if( db && noCheckpoint ){
    sqlite3_close(db);
    db = 0;
  }
  if( nExtra ){
    printf("%d cycles due to %d misses\n", nCount, nExtra);
  }
  if( eType==PATH_DB ){
    printf("SQLite version: %s\n", sqlite3_libversion());
    if( doIntegrityCk ){
      sqlite3_open(zDb, &db);
      sqlite3_prepare_v2(db, "PRAGMA integrity_check", -1, &pStmt, 0);
      while( sqlite3_step(pStmt)==SQLITE_ROW ){
        printf("integrity-check: %s\n", sqlite3_column_text(pStmt, 0));
      }
      sqlite3_finalize(pStmt);
      sqlite3_close(db);
      db = 0;
    }
  }
  printf("--count %d --max-id %d", nCount-nExtra, iMax);
  switch( eOrder ){
    case ORDER_RANDOM:  printf(" --random\n");  break;
    case ORDER_DESC:    printf(" --desc\n");    break;
    default:            printf(" --asc\n");     break;
  }
  if( eType==PATH_DB ){
    printf("--cache-size %d --jmode %s\n", iCache, zJMode);
    printf("--mmap %d%s\n", mmapSize, bBlobApi ? " --blob-api" : "");
    if( noSync ) printf("--nosync\n");
  }
  if( iPagesize ) printf("Database page size: %d\n", iPagesize);
  printf("Total elapsed time: %.3f\n", tmElapsed/1000.0);
  if( isUpdateTest ){
    printf("Microseconds per BLOB write: %.3f\n", tmElapsed*1000.0/nCount);
    printf("Content write rate: %.1f MB/s\n", nTotal/(1000.0*tmElapsed));
  }else{
    printf("Microseconds per BLOB read: %.3f\n", tmElapsed*1000.0/nCount);
    printf("Content read rate: %.1f MB/s\n", nTotal/(1000.0*tmElapsed));
  }
  return 0;
}


int main(int argc, char **argv){
  if( argc<3 ) showHelp();
  if( strcmp(argv[1],"init")==0 ){

      set fd [open $path w]
      puts -nonewline $fd [string repeat 1 $sz]
      close $fd
    }
  } {}

  set pwd [pwd]
  if {![string match {*[_%]*} $pwd]} {
    do_execsql_test 3.5 {
      SELECT path, size FROM fstree 
       WHERE path GLOB $pwd || '/subdir/*' ORDER BY 1
    } [list \
      "$pwd/subdir/x1.txt" 143 \
      "$pwd/subdir/x2.txt" 153 \
    ]
    do_execsql_test 3.6 {
      SELECT path, size FROM fstree
       WHERE path LIKE $pwd || '/subdir/%' ORDER BY 1
    } [list \
      "$pwd/subdir/x1.txt" 143 \
      "$pwd/subdir/x2.txt" 153 \
    ]
    do_execsql_test 3.7 {
      SELECT sum(size) FROM fstree WHERE path LIKE $pwd || '/subdir/%'
    } 296
    do_execsql_test 3.8 {
      SELECT size FROM fstree WHERE path = $pwd || '/subdir/x1.txt'
    } 143
  }

}


finish_test