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Comment:Update the [showdb] program so that the database file is read directly (bypassing the SQLite VFS) only if the --raw option is specified. Otherwise, it is read using the default VFS. Also, the URI syntax may be used on the command line to specify the name of the database file to examine, so an alternative VFS may be requested using a URI parameter.
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SHA1: e3c6d4b6e738c7ea015c0c809a5f7d1a94dda945
User & Date: dan 2015-08-04 15:29:43
Context
2015-08-04
19:06
Improve the usage comment on sqlite3_analyzer: show the available switches. check-in: 783f78e3 user: drh tags: trunk
15:29
Update the [showdb] program so that the database file is read directly (bypassing the SQLite VFS) only if the --raw option is specified. Otherwise, it is read using the default VFS. Also, the URI syntax may be used on the command line to specify the name of the database file to examine, so an alternative VFS may be requested using a URI parameter. check-in: e3c6d4b6 user: dan tags: trunk
15:23
Update the [showdb] program so that the database file is read directly (bypassing the SQLite VFS) only if the --raw option is specified. Otherwise, it is read using the default VFS. An alternative VFS may be specified by specifying the database file to open using the URI syntax. Closed-Leaf check-in: 9699e9bd user: dan tags: showdb-uri-option
14:18
In the sqlite3_analyzer.exe utility, show the depth of each btree and report the average fanout of indexes and WITHOUT ROWID tables. check-in: cd997770 user: drh tags: trunk
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#include <unistd.h>
#else
#include <io.h>
#endif

#include <stdlib.h>
#include <string.h>

#include "sqlite3.h"



static int pagesize = 1024;     /* Size of a database page */
static int db = -1;             /* File descriptor for reading the DB */
static int mxPage = 0;          /* Last page number */
static int perLine = 16;        /* HEX elements to print per line */






typedef long long int i64;      /* Datatype for 64-bit integers */


/*
** Convert the var-int format into i64.  Return the number of bytes
** in the var-int.  Write the var-int value into *pVal.
................................................................................

/* Report an out-of-memory error and die.
*/
static void out_of_memory(void){
  fprintf(stderr,"Out of memory...\n");
  exit(1);
}

/*



































































** Read content from the file.
**
** Space to hold the content is obtained from malloc() and needs to be
** freed by the caller.
*/
static unsigned char *getContent(int ofst, int nByte){
  unsigned char *aData;
  int got;
  aData = malloc(nByte+32);
  if( aData==0 ) out_of_memory();
  memset(aData, 0, nByte+32);







  lseek(db, ofst, SEEK_SET);
  got = read(db, aData, nByte);
  if( got>0 && got<nByte ) memset(aData+got, 0, nByte-got);

  return aData;
}
























/*
** Print a range of bytes as hex and as ascii.
*/
static unsigned char *print_byte_range(
  int ofst,          /* First byte in the range of bytes to print */
  int nByte,         /* Number of bytes to print */
  int printOfst      /* Add this amount to the index on the left column */
................................................................................
    zOfstFmt = " %05x: ";
  }else if( ((printOfst+nByte)&~0xffffff)==0 ){
    zOfstFmt = " %06x: ";
  }else{
    zOfstFmt = " %08x: ";
  }

  aData = getContent(ofst, nByte);
  for(i=0; i<nByte; i += perLine){
    fprintf(stdout, zOfstFmt, i+printOfst);
    for(j=0; j<perLine; j++){
      if( i+j>nByte ){
        fprintf(stdout, "   ");
      }else{
        fprintf(stdout,"%02x ", aData[i+j]);
      }
    }
    for(j=0; j<perLine; j++){
      if( i+j>nByte ){
        fprintf(stdout, " ");
      }else{
        fprintf(stdout,"%c", isprint(aData[i+j]) ? aData[i+j] : '.');
      }
    }
    fprintf(stdout,"\n");
................................................................................

/*
** Print an entire page of content as hex
*/
static void print_page(int iPg){
  int iStart;
  unsigned char *aData;
  iStart = (iPg-1)*pagesize;
  fprintf(stdout, "Page %d:   (offsets 0x%x..0x%x)\n",
          iPg, iStart, iStart+pagesize-1);
  aData = print_byte_range(iStart, pagesize, 0);
  free(aData);
}


/* Print a line of decode output showing a 4-byte integer.
*/
static void print_decode_line(
  unsigned char *aData,      /* Content being decoded */
................................................................................
static i64 localPayload(i64 nPayload, char cType){
  i64 maxLocal;
  i64 minLocal;
  i64 surplus;
  i64 nLocal;
  if( cType==13 ){
    /* Table leaf */
    maxLocal = pagesize-35;
    minLocal = (pagesize-12)*32/255-23;
  }else{
    maxLocal = (pagesize-12)*64/255-23;
    minLocal = (pagesize-12)*32/255-23;
  }
  if( nPayload>maxLocal ){
    surplus = minLocal + (nPayload-minLocal)%(pagesize-4);
    if( surplus<=maxLocal ){
      nLocal = surplus;
    }else{
      nLocal = minLocal;
    }
  }else{
    nLocal = nPayload;
................................................................................
  if( a[0]==2 || a[0]==5 ){
    print_decode_line(a, 8, 4, "Right child");
  }
  if( cellToDecode==(-2) && nCell>0 ){
    printf(" key: lx=left-child n=payload-size r=rowid\n");
  }
  if( showMap ){
    zMap = malloc(pagesize);
    memset(zMap, '.', pagesize);
    memset(zMap, '1', hdrSize);
    memset(&zMap[hdrSize], 'H', iCellPtr);
    memset(&zMap[hdrSize+iCellPtr], 'P', 2*nCell);
  }
  for(i=0; i<nCell; i++){
    int cofst = iCellPtr + i*2;
    char *zDesc;
................................................................................
      printf(" %03x: cell[%d] %s\n", cofst, i, zDesc);
    }else if( cellToDecode==(-1) || cellToDecode==i ){
      decodeCell(a, pgno, i, hdrSize, cofst-hdrSize);
    }
  }
  if( showMap ){
    printf("Page map:  (H=header P=cell-index 1=page-1-header .=free-space)\n");
    for(i=0; i<pagesize; i+=64){
      printf(" %03x: %.64s\n", i, &zMap[i]);
    }
    free(zMap);
  }
}

/*
** Decode a freelist trunk page.
*/
static void decode_trunk_page(
  int pgno,             /* The page number */
  int pagesize,         /* Size of each page */
  int detail,           /* Show leaf pages if true */
  int recursive         /* Follow the trunk change if true */
){
  int n, i;
  unsigned char *a;
  while( pgno>0 ){
    a = getContent((pgno-1)*pagesize, pagesize);
    printf("Decode of freelist trunk page %d:\n", pgno);
    print_decode_line(a, 0, 4, "Next freelist trunk page");
    print_decode_line(a, 4, 4, "Number of entries on this page");
    if( detail ){
      n = (int)decodeInt32(&a[4]);
      for(i=0; i<n; i++){
        unsigned int x = decodeInt32(&a[8+4*i]);
................................................................................
      if( i%5!=0 ) printf("\n");
    }
    if( !recursive ){
      pgno = 0;
    }else{
      pgno = (int)decodeInt32(&a[0]);
    }
    free(a);
  }
}

/*
** A short text comment on the use of each page.
*/
static char **zPageUse;
................................................................................
static void page_usage_msg(int pgno, const char *zFormat, ...){
  va_list ap;
  char *zMsg;

  va_start(ap, zFormat);
  zMsg = sqlite3_vmprintf(zFormat, ap);
  va_end(ap);
  if( pgno<=0 || pgno>mxPage ){
    printf("ERROR: page %d out of range 1..%d: %s\n",
            pgno, mxPage, zMsg);
    sqlite3_free(zMsg);
    return;
  }
  if( zPageUse[pgno]!=0 ){
    printf("ERROR: page %d used multiple times:\n", pgno);
    printf("ERROR:    previous: %s\n", zPageUse[pgno]);
    printf("ERROR:    current:  %s\n", zMsg);
................................................................................
    i = decodeVarint(a, &rowid);
    a += i;
    n += i;
  }
  if( nLocal<nPayload ){
    int ovfl = decodeInt32(a+nLocal);
    int cnt = 0;
    while( ovfl && (cnt++)<mxPage ){
      page_usage_msg(ovfl, "overflow %d from cell %d of page %d",
                     cnt, cellno, pgno);
      a = getContent((ovfl-1)*pagesize, 4);
      ovfl = decodeInt32(a);
      free(a);
    }
  }
}


/*
** Describe the usages of a b-tree page
................................................................................
){
  unsigned char *a;
  const char *zType = "corrupt node";
  int nCell;
  int i;
  int hdr = pgno==1 ? 100 : 0;

  if( pgno<=0 || pgno>mxPage ) return;
  a = getContent((pgno-1)*pagesize, pagesize);
  switch( a[hdr] ){
    case 2:  zType = "interior node of index";  break;
    case 5:  zType = "interior node of table";  break;
    case 10: zType = "leaf of index";           break;
    case 13: zType = "leaf of table";           break;
  }
  if( parent ){
................................................................................
    for(i=0; i<nCell; i++){
      int ofst;
      ofst = cellstart + i*2;
      ofst = a[ofst]*256 + a[ofst+1];
      page_usage_cell(a[hdr], a+ofst, pgno, i);
    }
  }
  free(a);
}

/*
** Determine page usage by the freelist
*/
static void page_usage_freelist(int pgno){
  unsigned char *a;
  int cnt = 0;
  int i;
  int n;
  int iNext;
  int parent = 1;

  while( pgno>0 && pgno<=mxPage && (cnt++)<mxPage ){
    page_usage_msg(pgno, "freelist trunk #%d child of %d", cnt, parent);
    a = getContent((pgno-1)*pagesize, pagesize);
    iNext = decodeInt32(a);
    n = decodeInt32(a+4);
    for(i=0; i<n; i++){
      int child = decodeInt32(a + (i*4+8));
      page_usage_msg(child, "freelist leaf, child %d of trunk page %d",
                     i, pgno);
    }
    free(a);
    parent = pgno;
    pgno = iNext;
  }
}

/*
** Determine pages used as PTRMAP pages
*/
static void page_usage_ptrmap(unsigned char *a){
  if( a[55] ){
    int usable = pagesize - a[20];
    int pgno = 2;
    int perPage = usable/5;
    while( pgno<=mxPage ){
      page_usage_msg(pgno, "PTRMAP page covering %d..%d",
                           pgno+1, pgno+perPage);
      pgno += perPage + 1;
    }
  }
}

/*
** Try to figure out how every page in the database file is being used.
*/
static void page_usage_report(const char *zDbName){
  int i, j;
  int rc;
  sqlite3 *db;
  sqlite3_stmt *pStmt;
  unsigned char *a;
  char zQuery[200];

  /* Avoid the pathological case */
  if( mxPage<1 ){
    printf("empty database\n");
    return;
  }

  /* Open the database file */
  rc = sqlite3_open(zDbName, &db);
  if( rc ){
    printf("cannot open database: %s\n", sqlite3_errmsg(db));
    sqlite3_close(db);
    return;
  }

  /* Set up global variables zPageUse[] and mxPage to record page
  ** usages */
  zPageUse = sqlite3_malloc( sizeof(zPageUse[0])*(mxPage+1) );
  if( zPageUse==0 ) out_of_memory();
  memset(zPageUse, 0, sizeof(zPageUse[0])*(mxPage+1));

  /* Discover the usage of each page */
  a = getContent(0, 100);
  page_usage_freelist(decodeInt32(a+32));
  page_usage_ptrmap(a);
  free(a);
  page_usage_btree(1, 0, 0, "sqlite_master");
  sqlite3_exec(db, "PRAGMA writable_schema=ON", 0, 0, 0);
  for(j=0; j<2; j++){
    sqlite3_snprintf(sizeof(zQuery), zQuery,
             "SELECT type, name, rootpage FROM SQLITE_MASTER WHERE rootpage"
             " ORDER BY rowid %s", j?"DESC":"");
    rc = sqlite3_prepare_v2(db, zQuery, -1, &pStmt, 0);
................................................................................
    }
    rc = sqlite3_finalize(pStmt);
    if( rc==SQLITE_OK ) break;
  }
  sqlite3_close(db);

  /* Print the report and free memory used */
  for(i=1; i<=mxPage; i++){
    printf("%5d: %s\n", i, zPageUse[i] ? zPageUse[i] : "???");
    sqlite3_free(zPageUse[i]);
  }
  sqlite3_free(zPageUse);
  zPageUse = 0;
}

................................................................................
  unsigned char *aHdr;
  unsigned char *a;
  int usable;
  int perPage;
  int i;

  /* Avoid the pathological case */
  if( mxPage<1 ){
    printf("empty database\n");
    return;
  }

  /* Make sure PTRMAPs are used in this database */
  aHdr = getContent(0, 100);
  if( aHdr[55]==0 ){
    printf("database does not use PTRMAP pages\n");
    return;
  }
  usable = pagesize - aHdr[20];
  perPage = usable/5;
  free(aHdr);
  printf("%5d: root of sqlite_master\n", 1);
  for(pgno=2; pgno<=mxPage; pgno += perPage+1){
    printf("%5d: PTRMAP page covering %d..%d\n", pgno,
           pgno+1, pgno+perPage);
    a = getContent((pgno-1)*pagesize, usable);
    for(i=0; i+5<=usable && pgno+1+i/5<=mxPage; i+=5){
      const char *zType = "???";
      unsigned int iFrom = decodeInt32(&a[i+1]);
      switch( a[i] ){
        case 1:  zType = "b-tree root page";        break;
        case 2:  zType = "freelist page";           break;
        case 3:  zType = "first page of overflow";  break;
        case 4:  zType = "later page of overflow";  break;
        case 5:  zType = "b-tree non-root page";    break;
      }
      printf("%5d: %s, parent=%u\n", pgno+1+i/5, zType, iFrom);
    }
    free(a);
  }
}

/*
** Print a usage comment
*/
static void usage(const char *argv0){
  fprintf(stderr, "Usage %s FILENAME ?args...?\n\n", argv0);
  fprintf(stderr,


    "args:\n"
    "    dbheader        Show database header\n"
    "    pgidx           Index of how each page is used\n"
    "    ptrmap          Show all PTRMAP page content\n"
    "    NNN..MMM        Show hex of pages NNN through MMM\n"
    "    NNN..end        Show hex of pages NNN through end of file\n"
    "    NNNb            Decode btree page NNN\n"
................................................................................
    "    NNNt            Decode freelist trunk page NNN\n"
    "    NNNtd           Show leaf freelist pages on the decode\n"
    "    NNNtr           Recursively decode freelist starting at NNN\n"
  );
}

int main(int argc, char **argv){
  struct stat sbuf;
  unsigned char zPgSz[2];
  if( argc<2 ){
    usage(argv[0]);
    exit(1);
  }
  db = open(argv[1], O_RDONLY);
  if( db<0 ){
    fprintf(stderr,"%s: can't open %s\n", argv[0], argv[1]);










    exit(1);
  }
  zPgSz[0] = 0;
  zPgSz[1] = 0;
  lseek(db, 16, SEEK_SET);
  if( read(db, zPgSz, 2)<2 ) memset(zPgSz, 0, 2);





  pagesize = zPgSz[0]*256 + zPgSz[1]*65536;
  if( pagesize==0 ) pagesize = 1024;


  printf("Pagesize: %d\n", pagesize);
  fstat(db, &sbuf);
  mxPage = (sbuf.st_size+pagesize-1)/pagesize;


  printf("Available pages: 1..%d\n", mxPage);
  if( argc==2 ){
    int i;
    for(i=1; i<=mxPage; i++) print_page(i);
  }else{
    int i;
    for(i=2; i<argc; i++){
      int iStart, iEnd;
      char *zLeft;
      if( strcmp(argv[i], "dbheader")==0 ){
        print_db_header();
        continue;
      }
      if( strcmp(argv[i], "pgidx")==0 ){
        page_usage_report(argv[1]);
        continue;
      }
      if( strcmp(argv[i], "ptrmap")==0 ){
        ptrmap_coverage_report(argv[1]);
        continue;
      }
      if( strcmp(argv[i], "help")==0 ){
        usage(argv[0]);
        continue;
      }
      if( !isdigit(argv[i][0]) ){
        fprintf(stderr, "%s: unknown option: [%s]\n", argv[0], argv[i]);
        continue;
      }
      iStart = strtol(argv[i], &zLeft, 0);
      if( zLeft && strcmp(zLeft,"..end")==0 ){
        iEnd = mxPage;
      }else if( zLeft && zLeft[0]=='.' && zLeft[1]=='.' ){
        iEnd = strtol(&zLeft[2], 0, 0);
      }else if( zLeft && zLeft[0]=='b' ){
        int ofst, nByte, hdrSize;
        unsigned char *a;
        if( iStart==1 ){
          ofst = hdrSize = 100;
          nByte = pagesize-100;
        }else{
          hdrSize = 0;
          ofst = (iStart-1)*pagesize;
          nByte = pagesize;
        }
        a = getContent(ofst, nByte);
        decode_btree_page(a, iStart, hdrSize, &zLeft[1]);
        free(a);
        continue;
      }else if( zLeft && zLeft[0]=='t' ){
        int detail = 0;
        int recursive = 0;
        int i;
        for(i=1; zLeft[i]; i++){
          if( zLeft[i]=='r' ) recursive = 1;
          if( zLeft[i]=='d' ) detail = 1;
        }
        decode_trunk_page(iStart, pagesize, detail, recursive);
        continue;
      }else{
        iEnd = iStart;
      }
      if( iStart<1 || iEnd<iStart || iEnd>mxPage ){
        fprintf(stderr,
          "Page argument should be LOWER?..UPPER?.  Range 1 to %d\n",
          mxPage);
        exit(1);
      }
      while( iStart<=iEnd ){
        print_page(iStart);
        iStart++;
      }
    }
  }
  close(db);
  return 0;
}







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#include <unistd.h>
#else
#include <io.h>
#endif

#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include "sqlite3.h"


static struct GlobalData {
  int pagesize;                   /* Size of a database page */
  int dbfd;                       /* File descriptor for reading the DB */
  int mxPage;                     /* Last page number */
  int perLine;                    /* HEX elements to print per line */
  int bRaw;                       /* True to access db file via OS APIs */
  sqlite3_file *pFd;              /* File descriptor for non-raw mode */
  sqlite3 *pDb;                   /* Database handle that owns pFd */
} g = {1024, -1, 0, 16,   0, 0, 0};


typedef long long int i64;      /* Datatype for 64-bit integers */


/*
** Convert the var-int format into i64.  Return the number of bytes
** in the var-int.  Write the var-int value into *pVal.
................................................................................

/* Report an out-of-memory error and die.
*/
static void out_of_memory(void){
  fprintf(stderr,"Out of memory...\n");
  exit(1);
}

/*
** Open a database connection.
*/
static sqlite3 *openDatabase(const char *zPrg, const char *zName){
  sqlite3 *db = 0;
  int flags = SQLITE_OPEN_READWRITE | SQLITE_OPEN_URI;
  int rc = sqlite3_open_v2(zName, &db, flags, 0);
  if( rc!=SQLITE_OK ){
    const char *zErr = sqlite3_errmsg(db);
    fprintf(stderr, "%s: can't open %s (%s)\n", zPrg, zName, zErr);
    sqlite3_close(db);
    exit(1);
  }
  return db;
}

/**************************************************************************
** Beginning of low-level file access functions.
**
** All low-level access to the database file read by this program is
** performed using the following four functions:
**
**   fileOpen()     - open the db file
**   fileClose()    - close the db file
**   fileRead()     - read raw data from the db file
**   fileGetsize()  - return the size of the db file in bytes
*/

/*
** Open the database file.
*/
static void fileOpen(const char *zPrg, const char *zName){
  assert( g.dbfd<0 );
  if( g.bRaw==0 ){
    int rc;
    void *pArg = (void *)(&g.pFd);
    g.pDb = openDatabase(zPrg, zName);
    rc = sqlite3_file_control(g.pDb, "main", SQLITE_FCNTL_FILE_POINTER, pArg);
    if( rc!=SQLITE_OK ){
      fprintf(stderr, 
          "%s: failed to obtain fd for %s (SQLite too old?)\n", zPrg, zName
      );
      exit(1);
    }
  }else{
    g.dbfd = open(zName, O_RDONLY);
    if( g.dbfd<0 ){
      fprintf(stderr,"%s: can't open %s\n", zPrg, zName);
      exit(1);
    }
  }
}

/*
** Close the database file opened by fileOpen()
*/
static void fileClose(){
  if( g.bRaw==0 ){
    sqlite3_close(g.pDb);
    g.pDb = 0;
    g.pFd = 0;
  }else{
    close(g.dbfd);
    g.dbfd = -1;
  }
}

/*
** Read content from the file.
**
** Space to hold the content is obtained from sqlite3_malloc() and needs 
** to be freed by the caller.
*/
static unsigned char *fileRead(sqlite3_int64 ofst, int nByte){
  unsigned char *aData;
  int got;
  aData = sqlite3_malloc(nByte+32);
  if( aData==0 ) out_of_memory();
  memset(aData, 0, nByte+32);
  if( g.bRaw==0 ){
    int rc = g.pFd->pMethods->xRead(g.pFd, (void*)aData, nByte, ofst);
    if( rc!=SQLITE_OK && rc!=SQLITE_IOERR_SHORT_READ ){
      fprintf(stderr, "error in xRead() - %d\n", rc);
      exit(1);
    }
  }else{
    lseek(g.dbfd, ofst, SEEK_SET);
    got = read(g.dbfd, aData, nByte);
    if( got>0 && got<nByte ) memset(aData+got, 0, nByte-got);
  }
  return aData;
}

/*
** Return the size of the file in byte.
*/
static sqlite3_int64 fileGetsize(void){
  sqlite3_int64 res = 0;
  if( g.bRaw==0 ){
    int rc = g.pFd->pMethods->xFileSize(g.pFd, &res);
    if( rc!=SQLITE_OK ){
      fprintf(stderr, "error in xFileSize() - %d\n", rc);
      exit(1);
    }
  }else{
    struct stat sbuf;
    fstat(g.dbfd, &sbuf);
    res = (sqlite3_int64)(sbuf.st_size);
  }
  return res;
}

/*
** End of low-level file access functions.
**************************************************************************/

/*
** Print a range of bytes as hex and as ascii.
*/
static unsigned char *print_byte_range(
  int ofst,          /* First byte in the range of bytes to print */
  int nByte,         /* Number of bytes to print */
  int printOfst      /* Add this amount to the index on the left column */
................................................................................
    zOfstFmt = " %05x: ";
  }else if( ((printOfst+nByte)&~0xffffff)==0 ){
    zOfstFmt = " %06x: ";
  }else{
    zOfstFmt = " %08x: ";
  }

  aData = fileRead(ofst, nByte);
  for(i=0; i<nByte; i += g.perLine){
    fprintf(stdout, zOfstFmt, i+printOfst);
    for(j=0; j<g.perLine; j++){
      if( i+j>nByte ){
        fprintf(stdout, "   ");
      }else{
        fprintf(stdout,"%02x ", aData[i+j]);
      }
    }
    for(j=0; j<g.perLine; j++){
      if( i+j>nByte ){
        fprintf(stdout, " ");
      }else{
        fprintf(stdout,"%c", isprint(aData[i+j]) ? aData[i+j] : '.');
      }
    }
    fprintf(stdout,"\n");
................................................................................

/*
** Print an entire page of content as hex
*/
static void print_page(int iPg){
  int iStart;
  unsigned char *aData;
  iStart = (iPg-1)*g.pagesize;
  fprintf(stdout, "Page %d:   (offsets 0x%x..0x%x)\n",
          iPg, iStart, iStart+g.pagesize-1);
  aData = print_byte_range(iStart, g.pagesize, 0);
  sqlite3_free(aData);
}


/* Print a line of decode output showing a 4-byte integer.
*/
static void print_decode_line(
  unsigned char *aData,      /* Content being decoded */
................................................................................
static i64 localPayload(i64 nPayload, char cType){
  i64 maxLocal;
  i64 minLocal;
  i64 surplus;
  i64 nLocal;
  if( cType==13 ){
    /* Table leaf */
    maxLocal = g.pagesize-35;
    minLocal = (g.pagesize-12)*32/255-23;
  }else{
    maxLocal = (g.pagesize-12)*64/255-23;
    minLocal = (g.pagesize-12)*32/255-23;
  }
  if( nPayload>maxLocal ){
    surplus = minLocal + (nPayload-minLocal)%(g.pagesize-4);
    if( surplus<=maxLocal ){
      nLocal = surplus;
    }else{
      nLocal = minLocal;
    }
  }else{
    nLocal = nPayload;
................................................................................
  if( a[0]==2 || a[0]==5 ){
    print_decode_line(a, 8, 4, "Right child");
  }
  if( cellToDecode==(-2) && nCell>0 ){
    printf(" key: lx=left-child n=payload-size r=rowid\n");
  }
  if( showMap ){
    zMap = sqlite3_malloc(g.pagesize);
    memset(zMap, '.', g.pagesize);
    memset(zMap, '1', hdrSize);
    memset(&zMap[hdrSize], 'H', iCellPtr);
    memset(&zMap[hdrSize+iCellPtr], 'P', 2*nCell);
  }
  for(i=0; i<nCell; i++){
    int cofst = iCellPtr + i*2;
    char *zDesc;
................................................................................
      printf(" %03x: cell[%d] %s\n", cofst, i, zDesc);
    }else if( cellToDecode==(-1) || cellToDecode==i ){
      decodeCell(a, pgno, i, hdrSize, cofst-hdrSize);
    }
  }
  if( showMap ){
    printf("Page map:  (H=header P=cell-index 1=page-1-header .=free-space)\n");
    for(i=0; i<g.pagesize; i+=64){
      printf(" %03x: %.64s\n", i, &zMap[i]);
    }
    sqlite3_free(zMap);
  }
}

/*
** Decode a freelist trunk page.
*/
static void decode_trunk_page(
  int pgno,             /* The page number */

  int detail,           /* Show leaf pages if true */
  int recursive         /* Follow the trunk change if true */
){
  int n, i;
  unsigned char *a;
  while( pgno>0 ){
    a = fileRead((pgno-1)*g.pagesize, g.pagesize);
    printf("Decode of freelist trunk page %d:\n", pgno);
    print_decode_line(a, 0, 4, "Next freelist trunk page");
    print_decode_line(a, 4, 4, "Number of entries on this page");
    if( detail ){
      n = (int)decodeInt32(&a[4]);
      for(i=0; i<n; i++){
        unsigned int x = decodeInt32(&a[8+4*i]);
................................................................................
      if( i%5!=0 ) printf("\n");
    }
    if( !recursive ){
      pgno = 0;
    }else{
      pgno = (int)decodeInt32(&a[0]);
    }
    sqlite3_free(a);
  }
}

/*
** A short text comment on the use of each page.
*/
static char **zPageUse;
................................................................................
static void page_usage_msg(int pgno, const char *zFormat, ...){
  va_list ap;
  char *zMsg;

  va_start(ap, zFormat);
  zMsg = sqlite3_vmprintf(zFormat, ap);
  va_end(ap);
  if( pgno<=0 || pgno>g.mxPage ){
    printf("ERROR: page %d out of range 1..%d: %s\n",
            pgno, g.mxPage, zMsg);
    sqlite3_free(zMsg);
    return;
  }
  if( zPageUse[pgno]!=0 ){
    printf("ERROR: page %d used multiple times:\n", pgno);
    printf("ERROR:    previous: %s\n", zPageUse[pgno]);
    printf("ERROR:    current:  %s\n", zMsg);
................................................................................
    i = decodeVarint(a, &rowid);
    a += i;
    n += i;
  }
  if( nLocal<nPayload ){
    int ovfl = decodeInt32(a+nLocal);
    int cnt = 0;
    while( ovfl && (cnt++)<g.mxPage ){
      page_usage_msg(ovfl, "overflow %d from cell %d of page %d",
                     cnt, cellno, pgno);
      a = fileRead((ovfl-1)*g.pagesize, 4);
      ovfl = decodeInt32(a);
      sqlite3_free(a);
    }
  }
}


/*
** Describe the usages of a b-tree page
................................................................................
){
  unsigned char *a;
  const char *zType = "corrupt node";
  int nCell;
  int i;
  int hdr = pgno==1 ? 100 : 0;

  if( pgno<=0 || pgno>g.mxPage ) return;
  a = fileRead((pgno-1)*g.pagesize, g.pagesize);
  switch( a[hdr] ){
    case 2:  zType = "interior node of index";  break;
    case 5:  zType = "interior node of table";  break;
    case 10: zType = "leaf of index";           break;
    case 13: zType = "leaf of table";           break;
  }
  if( parent ){
................................................................................
    for(i=0; i<nCell; i++){
      int ofst;
      ofst = cellstart + i*2;
      ofst = a[ofst]*256 + a[ofst+1];
      page_usage_cell(a[hdr], a+ofst, pgno, i);
    }
  }
  sqlite3_free(a);
}

/*
** Determine page usage by the freelist
*/
static void page_usage_freelist(int pgno){
  unsigned char *a;
  int cnt = 0;
  int i;
  int n;
  int iNext;
  int parent = 1;

  while( pgno>0 && pgno<=g.mxPage && (cnt++)<g.mxPage ){
    page_usage_msg(pgno, "freelist trunk #%d child of %d", cnt, parent);
    a = fileRead((pgno-1)*g.pagesize, g.pagesize);
    iNext = decodeInt32(a);
    n = decodeInt32(a+4);
    for(i=0; i<n; i++){
      int child = decodeInt32(a + (i*4+8));
      page_usage_msg(child, "freelist leaf, child %d of trunk page %d",
                     i, pgno);
    }
    sqlite3_free(a);
    parent = pgno;
    pgno = iNext;
  }
}

/*
** Determine pages used as PTRMAP pages
*/
static void page_usage_ptrmap(unsigned char *a){
  if( a[55] ){
    int usable = g.pagesize - a[20];
    int pgno = 2;
    int perPage = usable/5;
    while( pgno<=g.mxPage ){
      page_usage_msg(pgno, "PTRMAP page covering %d..%d",
                           pgno+1, pgno+perPage);
      pgno += perPage + 1;
    }
  }
}

/*
** Try to figure out how every page in the database file is being used.
*/
static void page_usage_report(const char *zPrg, const char *zDbName){
  int i, j;
  int rc;
  sqlite3 *db;
  sqlite3_stmt *pStmt;
  unsigned char *a;
  char zQuery[200];

  /* Avoid the pathological case */
  if( g.mxPage<1 ){
    printf("empty database\n");
    return;
  }

  /* Open the database file */
  db = openDatabase(zPrg, zDbName);






  /* Set up global variables zPageUse[] and g.mxPage to record page
  ** usages */
  zPageUse = sqlite3_malloc( sizeof(zPageUse[0])*(g.mxPage+1) );
  if( zPageUse==0 ) out_of_memory();
  memset(zPageUse, 0, sizeof(zPageUse[0])*(g.mxPage+1));

  /* Discover the usage of each page */
  a = fileRead(0, 100);
  page_usage_freelist(decodeInt32(a+32));
  page_usage_ptrmap(a);
  sqlite3_free(a);
  page_usage_btree(1, 0, 0, "sqlite_master");
  sqlite3_exec(db, "PRAGMA writable_schema=ON", 0, 0, 0);
  for(j=0; j<2; j++){
    sqlite3_snprintf(sizeof(zQuery), zQuery,
             "SELECT type, name, rootpage FROM SQLITE_MASTER WHERE rootpage"
             " ORDER BY rowid %s", j?"DESC":"");
    rc = sqlite3_prepare_v2(db, zQuery, -1, &pStmt, 0);
................................................................................
    }
    rc = sqlite3_finalize(pStmt);
    if( rc==SQLITE_OK ) break;
  }
  sqlite3_close(db);

  /* Print the report and free memory used */
  for(i=1; i<=g.mxPage; i++){
    printf("%5d: %s\n", i, zPageUse[i] ? zPageUse[i] : "???");
    sqlite3_free(zPageUse[i]);
  }
  sqlite3_free(zPageUse);
  zPageUse = 0;
}

................................................................................
  unsigned char *aHdr;
  unsigned char *a;
  int usable;
  int perPage;
  int i;

  /* Avoid the pathological case */
  if( g.mxPage<1 ){
    printf("empty database\n");
    return;
  }

  /* Make sure PTRMAPs are used in this database */
  aHdr = fileRead(0, 100);
  if( aHdr[55]==0 ){
    printf("database does not use PTRMAP pages\n");
    return;
  }
  usable = g.pagesize - aHdr[20];
  perPage = usable/5;
  sqlite3_free(aHdr);
  printf("%5d: root of sqlite_master\n", 1);
  for(pgno=2; pgno<=g.mxPage; pgno += perPage+1){
    printf("%5d: PTRMAP page covering %d..%d\n", pgno,
           pgno+1, pgno+perPage);
    a = fileRead((pgno-1)*g.pagesize, usable);
    for(i=0; i+5<=usable && pgno+1+i/5<=g.mxPage; i+=5){
      const char *zType = "???";
      unsigned int iFrom = decodeInt32(&a[i+1]);
      switch( a[i] ){
        case 1:  zType = "b-tree root page";        break;
        case 2:  zType = "freelist page";           break;
        case 3:  zType = "first page of overflow";  break;
        case 4:  zType = "later page of overflow";  break;
        case 5:  zType = "b-tree non-root page";    break;
      }
      printf("%5d: %s, parent=%u\n", pgno+1+i/5, zType, iFrom);
    }
    sqlite3_free(a);
  }
}

/*
** Print a usage comment
*/
static void usage(const char *argv0){
  fprintf(stderr, "Usage %s ?--uri? FILENAME ?args...?\n\n", argv0);
  fprintf(stderr,
    "switches:\n"
    "    --raw           Read db file directly, bypassing SQLite VFS\n"
    "args:\n"
    "    dbheader        Show database header\n"
    "    pgidx           Index of how each page is used\n"
    "    ptrmap          Show all PTRMAP page content\n"
    "    NNN..MMM        Show hex of pages NNN through MMM\n"
    "    NNN..end        Show hex of pages NNN through end of file\n"
    "    NNNb            Decode btree page NNN\n"
................................................................................
    "    NNNt            Decode freelist trunk page NNN\n"
    "    NNNtd           Show leaf freelist pages on the decode\n"
    "    NNNtr           Recursively decode freelist starting at NNN\n"
  );
}

int main(int argc, char **argv){
  sqlite3_int64 szFile;
  unsigned char *zPgSz;
  const char *zPrg = argv[0];     /* Name of this executable */
  char **azArg = argv;
  int nArg = argc;

  /* Check for the "--uri" or "-uri" switch. */
  if( nArg>1 ){
    if( sqlite3_stricmp("-raw", azArg[1])==0 
     || sqlite3_stricmp("--raw", azArg[1])==0
    ){
      g.bRaw = 1;
      azArg++;
      nArg--;
    }
  }

  if( nArg<2 ){
    usage(zPrg);
    exit(1);
  }





  fileOpen(zPrg, azArg[1]);
  szFile = fileGetsize();

  zPgSz = fileRead(16, 2);
  g.pagesize = zPgSz[0]*256 + zPgSz[1]*65536;
  if( g.pagesize==0 ) g.pagesize = 1024;
  sqlite3_free(zPgSz);

  printf("Pagesize: %d\n", g.pagesize);


  g.mxPage = (szFile+g.pagesize-1)/g.pagesize;

  printf("Available pages: 1..%d\n", g.mxPage);
  if( nArg==2 ){
    int i;
    for(i=1; i<=g.mxPage; i++) print_page(i);
  }else{
    int i;
    for(i=2; i<nArg; i++){
      int iStart, iEnd;
      char *zLeft;
      if( strcmp(azArg[i], "dbheader")==0 ){
        print_db_header();
        continue;
      }
      if( strcmp(azArg[i], "pgidx")==0 ){
        page_usage_report(zPrg, azArg[1]);
        continue;
      }
      if( strcmp(azArg[i], "ptrmap")==0 ){
        ptrmap_coverage_report(azArg[1]);
        continue;
      }
      if( strcmp(azArg[i], "help")==0 ){
        usage(zPrg);
        continue;
      }
      if( !isdigit(azArg[i][0]) ){
        fprintf(stderr, "%s: unknown option: [%s]\n", zPrg, azArg[i]);
        continue;
      }
      iStart = strtol(azArg[i], &zLeft, 0);
      if( zLeft && strcmp(zLeft,"..end")==0 ){
        iEnd = g.mxPage;
      }else if( zLeft && zLeft[0]=='.' && zLeft[1]=='.' ){
        iEnd = strtol(&zLeft[2], 0, 0);
      }else if( zLeft && zLeft[0]=='b' ){
        int ofst, nByte, hdrSize;
        unsigned char *a;
        if( iStart==1 ){
          ofst = hdrSize = 100;
          nByte = g.pagesize-100;
        }else{
          hdrSize = 0;
          ofst = (iStart-1)*g.pagesize;
          nByte = g.pagesize;
        }
        a = fileRead(ofst, nByte);
        decode_btree_page(a, iStart, hdrSize, &zLeft[1]);
        sqlite3_free(a);
        continue;
      }else if( zLeft && zLeft[0]=='t' ){
        int detail = 0;
        int recursive = 0;
        int i;
        for(i=1; zLeft[i]; i++){
          if( zLeft[i]=='r' ) recursive = 1;
          if( zLeft[i]=='d' ) detail = 1;
        }
        decode_trunk_page(iStart, detail, recursive);
        continue;
      }else{
        iEnd = iStart;
      }
      if( iStart<1 || iEnd<iStart || iEnd>g.mxPage ){
        fprintf(stderr,
          "Page argument should be LOWER?..UPPER?.  Range 1 to %d\n",
          g.mxPage);
        exit(1);
      }
      while( iStart<=iEnd ){
        print_page(iStart);
        iStart++;
      }
    }
  }
  fileClose();
  return 0;
}