Using the Setup Toolkit Function StampResource()

The information in this article applies to:

• Microsoft Windows Software Development Kit (SDK) for Windows version 3.1

SUMMARY

The StampResource() subroutine from the Setup toolkit can be used by a Setup script to overwrite a resource in an .EXE or .DLL with the specified data. The subroutine is useful for customizing a file's resources for the current installation.

The syntax of a StampResource() call is:

  StampResource szSection$, szKey$, szDst$, wResType%, wResId%,
                                                     szData$, cbData%

   CURSOR        1
   BITMAP        2
   ICON          3
   MENU          4
   DIALOG        5
   STRING        6
   FONTDIR       7
   FONT          8
   ACCELERATOR   9
   RCDATA        10
   GROUP_CURSOR  12
   GROUP_ICON    14
   VERSION       16

StampResource() finds the resource identified by wResType% and wResId% in the file, and checks the size of the resource. If cbData% is less than or equal to the size of the original resource, StampResource() overwrites the first cbData% bytes of it; otherwise, it fails. Therefore, the script author must make sure that cbData% is less than or equal to the size of the original resource, and that the original resource is large enough to hold the expected data.

MORE INFORMATION

The StampResource() subroutine can be used to overwrite a string resource in a file with a user's name, company, or serial number when the file is installed.

To overwrite a string resource, it is important to understand how string resources are stored.

A string table consists of one or more separate resources (or segments), each containing exactly 16 strings. The maximum length of each string is 255 bytes. One or more strings in a segment can be null or empty. The first byte in the string specifies the number of characters in the string. For null or empty strings, the first byte contains the value zero. The Windows Resource Compiler (RC) allocates 16 strings per segment and uses the identifier value to determine which segment is to contain the string. Strings with the same upper-12 bits in their identifiers are placed in the same segment.

With StampResource(), the wResId% is used to identify the segment; it should be the upper-12 bits of the identifiers in the section plus 1. There is no way to specify a specific string ID to overwrite. StampResource() starts writing data at the beginning of the specified segment and continues until cbData% bytes have been written. Therefore, with each call to StampResource(), one should assume that any of the previous strings in the segment will be overwritten. Because of this, make sure the strings that you "stamp" never share a segment with "read-only" strings. To do this, make the upper-12 bits of your stamp-string string identifiers different from those of your read-only-string string identifiers.

To write the new strings for the segment, fill in szData$ with the strings in the order of their identifiers. For simplicity's sake, it's recommended that the string IDs be consecutive (in the .RC file), starting with one whose lower-4 bits are 0 (zero). The string with 0000 in the lower-4 bits of its identifier should go first. For each string, put its length followed by the string itself in szData$. The length of szData$ should not be longer than the total length of the original strings in the segment.

For example, an application could set up three strings, which would be stamped with the user's name, the serial number, and the user's company name at installation time. The application's .RC file could be arranged as follows:

STRINGTABLE BEGIN 0x4500 "user name ------ Pad if necessary so you have room to use to" 0x4501 "serial number -- overwrite (total length of the new strings" 0x4502 "company name --- written must be less than the originals). " 0x0001 "read-only string1" 0x0004 "read-only string2" 0x1007 "read-only string3" 0x1008 "read-only string4" END

To stamp these strings with information collected from the user at set-up time, call StampResource() from the Setup script with &H451 for wResId%. &H means the number following is in hexadecimal. &H451 is the upper-12 bits of the stamp-string string IDs plus 1.

   szUser$="Jane Doe"
   szSerial$="0123456789"
   szCo$="ACME Corp"
   szDat$=CHR$(LEN(szUser$))+szUser$+CHR$(LEN(szSerial$))+szSerial$
   szDat$=szDat$+CHR$(LEN(szCo$))+szCo$
   StampResource "Files","gen",DEST$,6,&H451,szDat$,LEN(szDat$)