From 4e6861d23da2e05fdeff2fc913e87c1b7b1976c8 Mon Sep 17 00:00:00 2001
From: drh <drh@noemail.net>
Date: Mon, 20 Jul 2020 14:54:36 +0000
Subject: [PATCH] Add the "enlargedb" utility program used to construct very
 large database files for testing.

FossilOrigin-Name: 66858d87507bfdd17bb76c0afb1108ad5dec752438a79bf57f0f51690232e943
---
 manifest         | 14 +++++-----
 manifest.uuid    |  2 +-
 tool/enlargedb.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 75 insertions(+), 9 deletions(-)
 create mode 100644 tool/enlargedb.c

diff --git a/manifest b/manifest
index fb324fa973..3a2e4bcd08 100644
--- a/manifest
+++ b/manifest
@@ -1,6 +1,6 @@
 B 7a876209a678a34c198b54ceef9e3c041f128a14dc73357f6a57cadadaa6cf7b
-C Initial\schanges\sto\sallow\sdatabase\sup\sto\s281TB\sin\ssize.
-D 2020-07-20T12:47:32.233
+C Add\sthe\s"enlargedb"\sutility\sprogram\sused\sto\sconstruct\svery\slarge\sdatabase\nfiles\sfor\stesting.
+D 2020-07-20T14:54:36.782
 F Makefile.in 19374a5db06c3199ec1bab71ab74a103d8abf21053c05e9389255dc58083f806
 F Makefile.msc 48f5a3fc32672c09ad73795749f6253e406a31526935fbbffd8f021108d54574
 F autoconf/Makefile.am a8d1d24affe52ebf8d7ddcf91aa973fa0316618ab95bb68c87cabf8faf527dc8
@@ -66,6 +66,7 @@ F test/upfrom3.test 7dab379d128e8dd7beb2055b295fb113c7ba93e8c2038f5ddb7a4a10f0eb
 F test/upfromfault.test 70ecf8eb85559727a487283f69374e3ae39879e994d8a2437c49d7c05ecb70c9
 F test/wherelimit2.test 657a3f24aadee62d058c5091ea682dc4af4b95ffe32f137155be49799a58e721
 F test/window1.test e52b81fff0c3cb122a1240f336688eb81bea2967a99c4ddb78969adec7aadc2a
+F tool/enlargedb.c 3e8b2612b985cfa7e3e8800031ee191b43ae80de96abb5abbd5eada62651ee21
 F tool/lemon.c 600a58b9d1b8ec5419373982428e927ca208826edacb91ca42ab94514d006039
 F tool/mkautoconfamal.sh f62353eb6c06ab264da027fd4507d09914433dbdcab9cb011cdc18016f1ab3b8
 F tool/mkpragmatab.tcl ae5585ae76ca26e4d6ccd5ea9cdebaf5efefb318bf989497a0e846cd711d9ab1
@@ -73,10 +74,7 @@ F tool/mksqlite3c.tcl f4ef476510eca4124c874a72029f1e01bc54a896b1724e8f9eef0d8bfa
 F tool/mksqlite3h.tcl 1f5e4a1dbbbc43c83cc6e74fe32c6c620502240b66c7c0f33a51378e78fc4edf
 F tool/showlocks.c 9cc5e66d4ebbf2d194f39db2527ece92077e86ae627ddd233ee48e16e8142564
 F tool/speed-check.sh 615cbdf50f1409ef3bbf9f682e396df80f49d97ed93ed3e61c8e91fae6afde58
-P 020dbfa2aef20e5872cc3e785d99f45903843401292114b5092b9c8aa829b9c3
-R ab2ebf91e53f6501695c6ee9adc86286
-T *branch * larger-databases
-T *sym-larger-databases *
-T -sym-trunk *
+P 9cb7da9bdb666ea40771513b89591dca275f1e92092b39190df747e3797178a3
+R 9067d26895bc3a2e17574c32eefe8d76
 U drh
-Z 75b6d7d462ec8aff5320b5004ad4c7b9
+Z a6e9581b3af88e284f742d70fddd747a
diff --git a/manifest.uuid b/manifest.uuid
index 47fb46cd08..e30ffe29d8 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-9cb7da9bdb666ea40771513b89591dca275f1e92092b39190df747e3797178a3
\ No newline at end of file
+66858d87507bfdd17bb76c0afb1108ad5dec752438a79bf57f0f51690232e943
\ No newline at end of file
diff --git a/tool/enlargedb.c b/tool/enlargedb.c
new file mode 100644
index 0000000000..dab5ef1f1c
--- /dev/null
+++ b/tool/enlargedb.c
@@ -0,0 +1,68 @@
+/*
+** Try to enlarge an SQLite database by appending many unused pages.
+** The resulting database will fail PRAGMA integrity_check due to the
+** appended unused pages, but it should work otherwise.
+**
+** Usage:
+**
+**        enlargedb  DATABASE   N
+**
+** Adds N blank pages onto the end of DATABASE.  N can be decimal
+** or hex.  The total number of pages after adding must be no greater
+** than 4294967297
+*/
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+int main(int argc, char **argv){
+  char *zEnd;
+  long long int toAppend;
+  long long int currentSz;
+  long long int newSz;
+  FILE *f;
+  size_t got;
+  int pgsz;
+  char zero = 0;
+  unsigned char buf[100];
+
+  if( argc!=3 ) goto usage_error;
+  toAppend = strtoll(argv[2], &zEnd, 0);
+  if( zEnd==argv[2] || zEnd[0] ) goto usage_error;
+  if( toAppend<1 ){
+    fprintf(stderr, "N must be at least 1\n");
+    exit(1);
+  }
+  f = fopen(argv[1], "r+b");
+  if( f==0 ){
+    fprintf(stderr, "cannot open \"%s\" for reading and writing\n", argv[1]);
+    exit(1);
+  }
+  got = fread(buf, 1, sizeof(buf), f);
+  if( got!=sizeof(buf) ) goto not_valid_db;
+  if( strcmp((char*)buf,"SQLite format 3")!=0 ) goto not_valid_db;
+  pgsz = (buf[16]<<8) + buf[17];
+  if( pgsz==1 ) pgsz = 65536;
+  if( pgsz<512 || pgsz>65536 || (pgsz&(pgsz-1))!=0 ) goto not_valid_db;
+  currentSz = (buf[28]<<24) + (buf[29]<<16) + (buf[30]<<8) + buf[31];
+  newSz = currentSz + toAppend;
+  if( newSz > 0xffffffff ) newSz = 0xffffffff;
+  buf[28] = (newSz>>24) & 0xff;
+  buf[29] = (newSz>>16) & 0xff;
+  buf[30] = (newSz>>8) & 0xff;
+  buf[31] = newSz & 0xff;
+  fseek(f, 28, SEEK_SET);
+  fwrite(&buf[28],4,1,f);
+  fseek(f, (long)(newSz*pgsz - 1), SEEK_SET);
+  fwrite(&zero,1,1,f);
+  fclose(f);
+  return 0;  
+
+not_valid_db:
+  fprintf(stderr,"not a valid database: %s\n", argv[1]);
+  exit(1);  
+
+usage_error:
+  fprintf(stderr,"Usage: %s DATABASE N\n", argv[0]);
+  exit(1);
+}