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Revise file_format
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The changes should allow for the .simplearchive file to be directly
outputted to standard out in a single pass.

Resolves #10 .
This commit is contained in:
Stephen Seo 2024-07-02 14:02:38 +09:00
parent 3172920c9c
commit eb1f09b551
1 changed files with 23 additions and 19 deletions
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file_format.md
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@ -9,26 +9,30 @@ First 18 bytes of file will be:
SIMPLE_ARCHIVE_VER SIMPLE_ARCHIVE_VER
Next 2 bytes is 16-bit unsigned integer "version" in big-endian. In this case, Next 2 bytes is 16-bit unsigned integer "version" in big-endian. In this case,
will be zero. it will be zero.
Next 4 bytes is 32-bit unsigned integer "file count" in big-endian which will Next 4 bytes are bit-flags.
indicate the number of files in this archive.
For each file: 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.
2. X bytes of "compressor cmd+args" (length defined by previous value).
3. 2 bytes is 16-bit unsigned integer "decompressor cmd+args" in big-endian.
4. X bytes of "decompressor cmd+args" (length defined by previous value).
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. 1. 2 bytes is 16-bit unsigned integer "filename length" in big-endian.
2. X bytes of filename (defined by previous value). 2. X bytes of filename (length defined by previous value).
3. 2 bytes is 16-bit unsigned integer "compressor cmd+args" in big-endian. 3. 8 bytes 64-bit unsigned integer "size of filename in this archive file".
4. X bytes of "compressor cmd+args" (defined by previous value). 4. X bytes file data (length defined by previous value).
5. 2 bytes is 16-bit unsigned integer "decompressor cmd+args" in big-endian.
6. X bytes of "decompressor cmd+args" (defined by previous value).
7. 8 bytes 64-bit unsigned integer "location of filename in this archive file".
8. 8 bytes 64-bit unsigned integer "size of filename in this archive file".
Note that if archiving without compressor/decompressor, the byte values for
them will be 0 and there will be no strings for the compressor/decompressor
commands (lines 4 and 6 in previous per-file entry will not exist).
The remaining bytes in the file are the files to be included in the archive file
concatenated together. Their locations and sizes should match what was listed
before.