luau-unzip/scripts/generate_invalid_version_zip.luau

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local fs = require("@lune/fs")
local stdio = require("@lune/stdio")
local process = require("@lune/process")
-- stylua: ignore
local function createZip(version: number): buffer
version = version or math.random(63, 100)
print("Using version:", version)
local data = buffer.create(98)
local pos = 0
-- Local file header (30 bytes)
buffer.writeu32(data, pos, 0x04034b50); pos += 4
print("Local header starts at:", 0)
-- Track rest of local header position
buffer.writeu16(data, pos, version); pos += 2
buffer.writeu16(data, pos, 0); pos += 2 -- flags
buffer.writeu16(data, pos, 0); pos += 2 -- compression method
buffer.writeu32(data, pos, 0); pos += 4 -- timestamp
buffer.writeu32(data, pos, 0); pos += 4 -- crc32
buffer.writeu32(data, pos, 0); pos += 4 -- compressed size
buffer.writeu32(data, pos, 0); pos += 4 -- uncompressed size
buffer.writeu16(data, pos, 0); pos += 2 -- filename length
buffer.writeu16(data, pos, 0); pos += 2 -- extra field length
-- Central directory
local cdOffset = pos
print("CD fields:")
buffer.writeu32(data, pos, 0x02014b50); pos += 4 -- signature
print("- signature:", buffer.readu32(data, cdOffset))
buffer.writeu16(data, pos, 20); pos += 2 -- version made by
print("- version made by:", buffer.readu16(data, cdOffset + 4))
buffer.writeu16(data, pos, version); pos += 2 -- version needed
print("- version needed:", buffer.readu16(data, cdOffset + 6))
print("CD additional fields:")
print("- flags:", buffer.readu16(data, cdOffset + 8))
print("- compression:", buffer.readu16(data, cdOffset + 10))
print("- local header offset:", buffer.readu32(data, cdOffset + 42))
buffer.writeu16(data, pos, 0); pos += 2 -- flags
buffer.writeu16(data, pos, 0); pos += 2 -- compression
buffer.writeu32(data, pos, 0); pos += 4 -- timestamp
buffer.writeu32(data, pos, 0); pos += 4 -- crc32
buffer.writeu32(data, pos, 0); pos += 4 -- compressed size
buffer.writeu32(data, pos, 0); pos += 4 -- uncompressed size
buffer.writeu16(data, pos, 0); pos += 2 -- filename length
buffer.writeu16(data, pos, 0); pos += 2 -- extra field length
buffer.writeu16(data, pos, 0); pos += 2 -- comment length
buffer.writeu16(data, pos, 0); pos += 2 -- disk number
buffer.writeu16(data, pos, 0); pos += 2 -- internal attrs
buffer.writeu32(data, pos, 0); pos += 4 -- external attrs
buffer.writeu32(data, pos, 0); pos += 4 -- local header offset
-- End of central directory
print("EoCD fields:")
buffer.writeu32(data, pos, 0x06054b50); pos += 4 -- signature
buffer.writeu16(data, pos, 0); pos += 2 -- disk number
buffer.writeu16(data, pos, 0); pos += 2 -- disk with cd
buffer.writeu16(data, pos, 1); pos += 2 -- disk entries (1 file)
print("- disk entries:", buffer.readu16(data, pos - 18))
buffer.writeu16(data, pos, 1); pos += 2 -- total entries (1 file)
print("- total entries:", buffer.readu16(data, pos - 16))
buffer.writeu32(data, pos, 46); pos += 4 -- cd size (fixed size)
print("- cd size:", buffer.readu32(data, pos - 14))
buffer.writeu32(data, pos, 30); pos += 4 -- cd offset (fixed offset)
print("- cd offset:", buffer.readu32(data, pos - 10))
buffer.writeu16(data, pos, 0); pos += 2 -- comment length
print("Final buffer size:", pos)
local result = buffer.create(pos)
buffer.copy(result, 0, data, 0, pos)
return result
end
-- Write the invalid ZIP file
local versionNum = assert(tonumber(process.args[1] or stdio.prompt("text", "Version number:")))
local zip = createZip(versionNum)
fs.writeFile("tests/data/invalid_version.zip", zip)
print(`Generated invalid_version.zip with version requirement {versionNum // 10}.{versionNum % 10}`)