SimpleArchiver/file_format.md

File Format

Note that any unused bytes/bits should be zeroed-out before being written.

Format Version 0

File extension is "*.simplearchive"

First 18 bytes of file will be:

SIMPLE_ARCHIVE_VER

Next 2 bytes is 16-bit unsigned integer "version" in big-endian. In this case, it will be zero.

Next 4 bytes are bit-flags.

1. The first byte
   1. The first bit is set if de/compressor is set for this archive.

The remaining unused flags are reserved for future revisions and are currently ignored.

If the previous "de/compressor is set" flag is enabled, then the next section is added:

1. 2 bytes is 16-bit unsigned integer "compressor cmd+args" in big-endian. This does not include the NULL at the end of the string.
2. X bytes of "compressor cmd+args" (length defined by previous value). Is a NULL-terminated string.
3. 2 bytes is 16-bit unsigned integer "decompressor cmd+args" in big-endian. This does not include the NULL at the end of the string.
4. X bytes of "decompressor cmd+args" (length defined by previous value). Is a NULL-terminated string.

The next 4 bytes is 32-bit unsigned integer "file count" in big-endian which will indicate the number of files in this archive.

Following the file-count bytes, the following bytes are added for each file:

1. 2 bytes is 16-bit unsigned integer "filename length" in big-endian. This does not include the NULL at the end of the string.
2. X bytes of filename (length defined by previous value). Is a NULL-terminated string.
3. 4 bytes bit-flags
   1. The first byte
      1. The first bit is set if the file is a symbolic link.
   2. The second byte.
      1. Currently unused.
   3. The third byte.
      1. Currently unused.
   4. The fourth byte.
      1. Currently unused.
4. If this file is a symbolic link:
   1. 2 bytes is 16-bit unsigned integer "link target absolute path" in big-endian. This does not include the NULL at the end of the string.
   2. X bytes of link-target-absolute-path (length defined by previous value). Is a NULL-terminated string. If the previous "size" value is 0, then this entry does not exist and should be skipped.
   3. 2 bytes is 16-bit unsigned integer "link target relative path" in big-endian. This does not include the NULL at the end of the string.
   4. X bytes of link-target-relative-path (length defined by previous value). Is a NULL-terminated string. If the previous "size" value is 0, then this entry does not exist and should be skipped.
5. If this file is NOT a symbolic link:
   1. 8 bytes 64-bit unsigned integer "size of filename in this archive file" in big-endian.
   2. X bytes file data (length defined by previous value).