86 lines
2.7 KiB
Swift
86 lines
2.7 KiB
Swift
import Foundation
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struct RDEPUBChapterWindowSnapshot {
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/// 窗口中的章节（有序：prev, current, next）
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let chapters: [RDEPUBRuntimeChapter]
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/// 展平后的连续页数组（供 RDReaderView 消费）
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/// 窗口内页码不写回 RDEPUBTextPage 模型；
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/// flattenedPages 的数组下标就是窗口内连续页码（从 0 开始）。
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let flattenedPages: [RDEPUBTextPage]
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/// 当前章在 chapters 数组中的索引
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let anchorChapterIndex: Int
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/// 当前章在 flattenedPages 中的起始页码（从 0 开始，窗口内编号）
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let anchorPageOffset: Int
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/// 当前窗口首章的 spineIndex，用于调试日志和跨窗口映射
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let windowStartSpineIndex: Int
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// MARK: - 构建
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/// 从章节窗口构建快照
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static func from(
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currentChapter: RDEPUBRuntimeChapter,
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previousChapter: RDEPUBRuntimeChapter?,
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nextChapter: RDEPUBRuntimeChapter?
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) -> RDEPUBChapterWindowSnapshot {
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var chapters: [RDEPUBRuntimeChapter] = []
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var anchorIndex = 0
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var pageOffset = 0
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if let prev = previousChapter {
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chapters.append(prev)
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anchorIndex = 1
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pageOffset = prev.pages.count
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}
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chapters.append(currentChapter)
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if let next = nextChapter {
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chapters.append(next)
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}
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// 展平页数组
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var allPages: [RDEPUBTextPage] = []
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for (chIdx, ch) in chapters.enumerated() {
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for var page in ch.pages {
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page.chapterIndex = chIdx
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allPages.append(page)
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}
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}
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let windowStartSpineIndex = chapters.first?.spineIndex ?? currentChapter.spineIndex
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return RDEPUBChapterWindowSnapshot(
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chapters: chapters,
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flattenedPages: allPages,
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anchorChapterIndex: anchorIndex,
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anchorPageOffset: pageOffset,
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windowStartSpineIndex: windowStartSpineIndex
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)
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}
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// MARK: - 查询
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/// 窗口内页码（即 flattenedPages 下标）-> 所属章节
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func chapterForPage(flattenedPageIndex: Int) -> RDEPUBRuntimeChapter? {
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var offset = 0
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for ch in chapters {
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if flattenedPageIndex < offset + ch.pages.count {
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return ch
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}
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offset += ch.pages.count
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}
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return nil
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}
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/// 窗口内页码（即 flattenedPages 下标）-> 所属章节的 spineIndex
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func spineIndexForPage(flattenedPageIndex: Int) -> Int? {
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return chapterForPage(flattenedPageIndex: flattenedPageIndex)?.spineIndex
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}
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/// 总页数（窗口内）
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var pageCount: Int { flattenedPages.count }
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} |