gistfile1.swift

class PDFViewBitmapCacheKey: Hashable {
    let name: String
    let width: Int
    let height: Int
    let scaleMode: PDFImage.ScaleMode
    let page: PDFImage.Page

    init(name: String, size: CGSize, scaleMode: PDFImage.ScaleMode, page: PDFImage.Page) {
        self.name = name
        // Note that we want to make sure we're using integer values for the size, or we might fall prey to float imprecisions
        self.width = Int(size.width)
        self.height = Int(size.height)
        self.scaleMode = scaleMode
        self.page = page
    }

    var hashValue: Int {
        return name.hashValue |
              width.hashValue << (sizeof(Int) * 1) |
             height.hashValue << (sizeof(Int) * 2) |
          scaleMode.hashValue << (sizeof(Int) * 3) |
               page.hashValue << (sizeof(Int) * 4)
    }
}