mirror of
https://github.com/simplex-chat/simplex-chat.git
synced 2026-09-27 20:08:34 +00:00
48 lines
1.7 KiB
TypeScript
48 lines
1.7 KiB
TypeScript
import * as zlib from "zlib"
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const LOCAL_FILE_HEADER = 0x04034b50
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const CENTRAL_DIRECTORY_HEADER = 0x02014b50
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const END_OF_CENTRAL_DIRECTORY = 0x06054b50
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const ZIP_VERSION = 20
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const LOCAL_HEADER_SIZE = 30
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const CENTRAL_ENTRY_SIZE = 46
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const END_RECORD_SIZE = 22
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export function storedZip(files: {[name: string]: string}): Buffer {
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const local: Buffer[] = []
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const central: Buffer[] = []
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let offset = 0
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for (const [name, content] of Object.entries(files)) {
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const nameBuf = Buffer.from(name)
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const data = Buffer.from(content)
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const crc = zlib.crc32(data)
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const header = Buffer.alloc(LOCAL_HEADER_SIZE)
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header.writeUInt32LE(LOCAL_FILE_HEADER, 0)
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header.writeUInt16LE(ZIP_VERSION, 4)
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header.writeUInt32LE(crc, 14)
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header.writeUInt32LE(data.length, 18)
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header.writeUInt32LE(data.length, 22)
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header.writeUInt16LE(nameBuf.length, 26)
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local.push(header, nameBuf, data)
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const entry = Buffer.alloc(CENTRAL_ENTRY_SIZE)
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entry.writeUInt32LE(CENTRAL_DIRECTORY_HEADER, 0)
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entry.writeUInt16LE(ZIP_VERSION, 4)
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entry.writeUInt16LE(ZIP_VERSION, 6)
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entry.writeUInt32LE(crc, 16)
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entry.writeUInt32LE(data.length, 20)
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entry.writeUInt32LE(data.length, 24)
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entry.writeUInt16LE(nameBuf.length, 28)
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entry.writeUInt32LE(offset, 42)
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central.push(entry, nameBuf)
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offset += header.length + nameBuf.length + data.length
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}
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const centralBuf = Buffer.concat(central)
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const end = Buffer.alloc(END_RECORD_SIZE)
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end.writeUInt32LE(END_OF_CENTRAL_DIRECTORY, 0)
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end.writeUInt16LE(Object.keys(files).length, 8)
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end.writeUInt16LE(Object.keys(files).length, 10)
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end.writeUInt32LE(centralBuf.length, 12)
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end.writeUInt32LE(offset, 16)
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return Buffer.concat([...local, centralBuf, end])
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}
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