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diff --git a/doc/devel/pkgformat b/doc/devel/pkgformat new file mode 100644 index 0000000..69a2513 --- /dev/null +++ b/doc/devel/pkgformat @@ -0,0 +1,174 @@ +The .pkg/.ndx format as used for Starcon.pkg on the 3DO cd. +Acquired directly from the source. + +This format is used both in the file and is memory. There are some +little differences; where this is this is the case, this is +mentioned below in square brackets. + +Everything is stored LSB first. + +This document talks about packaged files. +Packaged files have multiple resources stored in one file. All the resources +in one package are stored in a single file, whose name is specified in +p.packmem. The name may be '\0', in which case the package file itself +is used. +Non-packaged files have one resource per file. The name is specified +in each resource instance info field. + +Main header: (resinit.c, _GetResFileData()) +position length meaning +0x00 2 Whether or not the file is packaged (res_flags) + bit 0: 0 - the .pkg file is not packaged + 1 - the .pkg file is packaged +0x02 4 offset from the beginning of the file where the list + of package information is stored (packmem_list_offs) +0x06 4 offset from the beginning of the file where the list + of pathnames is stored (path_list_offs) +0x0a 4 offset from the beginning of the file where the list + of file names is stored (file_list_offs) +0x0e 2 number of packages in the file (num_packages) +0x10 2 number of types of packages present in the file (num_types) +0x12 4 length of this header. (index_info.header_len) + (unused if the .pkg file is not packaged) +0x16 8*num_packages: + On position i the information for package i + 1 is + stored. There is no package 0. + 4 p.packmem_info + bits 0-7: number of resource types + bits 8-20: number of resource instances + bits 21-31: + For packaged files: index in file_list_offs of the + file name for this resource + For non-packaged files: unused (0) + 4 p.flags_and_data_loc + MSB is flags, rest is data_loc, + if MSB == 0, then of the data_loc only the low 16 bits + are used as a MEM_HANDLE [only in memory], + if MSB == 0xff, then the data_loc is an offset in the + file to the actual data +0x16+8*num_packages Type information + 2*num_types + t.instance_count + The number of instances there are of this type. + On position i the instance count for type i + 1 is + stored. There's no type 0. +packmem_list_offs (should be directly after the index info): + for each of the num_packages packages: + for each of the resource types for this package + (as in p.packmem_info): + 4 bits 0-7: The type number for this type. What that + number means isn't specified, and may + vary per .pkg file. + For the 3DO SC2 starcon.pkg file these are: + 0 - not a type + 1 - Graphics data (GFXRES) + 2 - String data (STRTAB) + 3 - Music data (MUSICRES) + 4 - Resource index (RES_INDEX) + 5 - Code (CODE) + bits 8-20: The instance number of the first instance + of this type in this package. Every + following instance has a number 1 higher + than the one before. + bits 21-31: number of resources of this type in the + package + for each of the resource instances for this package + (as in p.packmem_info): + 2 if this is a packaged file: multiply by 4 to get + the length of this resource. [1] + if this is a file that is not packaged: + index in file_list_offs of the file name for + this resource. + [the same position is in memory used as a MEM_HANDLE + to the actual data] +path_list_offs (should be directly after the packmem list) + ? null terminated path strings, indexed from the file list + table +file_list_offs (should be directly after the path list) + ? A number of file info structures. For packaged files, + these are indexed from the p.packmem_info (so (at most) + one per package). For non-packaged files, these are + indexed from an entry for an instance from + p.packmem_list (so possibly more per package) + These structures are in this form: + 13 file info: + 2 location relative to path_list_offs of the + the path to this file, or 0xffff if no path. + 8 file name (8 chars or null-terminated) + 3 extension (3 chars or null-terminated) + +The following section is present in the package only for packaged files. +For non-packaged files, the fields below exist in the external file indicated +by p.packmem_info.file_index. +For each package p: +p.data_loc for each type p.t: + for each instance p.t.i: + p.t.i.length + the data for the resource + As the length always is a multiple of 4, the last + few bytes may not belong to the resource itself. + Their content is unspecified. + + +Resources with type 'resource index' (type 4 in the 3DO sc2 starcon.pkg file) +are files with the same format as this .pkg file itself. + + +The information above, about the format used on the 3DO, is gathered from +the resource library sources itself. +The information below, about the format used on the PC, and for SC1, +is induced from the packed files themselves. + + +The format used in SC1 is somewhat different. The differences are listed +here: +0x02 4 offset from the beginning of the file where the list + of pathnames is stored (path_list_offs) +0x06 4 offset from the beginning of the file where the list + of file names is stored (file_list_offs) +0x0a 4 offset from the beginning of the file where the list + of package information is stored (packmem_list_offs) +0x0e 2 number of types of packages present in the file (num_types) +0x10 2 ? +0x12 2 number of packages in the file (num_packages) +0x14 2 ? +packmem_list_offs + 4 as for the 3DO + 2 if this is a packaged file: the length of this resource. + No multiplication by 2 or 4 as on other platforms. [1] + + +The format used in the DOS version of SC2 is different yet again. +The differences to the 3DO version are listed here: +0x10 1 number of types of packages present in the file (num_types) +0x11 1 unknown +packmem_list_offs + 4 as for the 3DO + 2 if this is a packaged file: multiply by 2 to get + the length of this resource. [1] + + +[1]. In some of the packaged .pkg files used in the Toys For Bob games, +the length field of a resource instance is overflowed for some resources, +even though the use of a multiplier will have had the purpose of preventing +this. The actual size is a multiple of 0x10000 times the multiplier larger. +This occurs in 18 packages in the PC version of Star Control II, in +1 package of the Amiga version of Star Control 1, and in 2 packages of +the PC version of The Horde. The PC version of Star Control 1, and the 3DO +version of Star Control II don't have such overflows. +The actual size of a package can be determined by looking at the +difference in offset between two subsequent packages. +Where the package contains only one resource instance, the extra data can +only belong to that instance. Where a package contains more than one +resource instance, the extra data most likely belongs to the last resource, +as an incorrect size results in an incorrect offset for all subsequent +instances in the package, which would most likely have been noticed due to +corruption in the game. + + +The part pointed to by file_list_offs is frequently followed by a bit of +unused space, which may contain garbage. + + +Initial version of this file 2002-10-10 by Serge van den Boom. + |