Justin Mitchell
d364e54a69
Implements bidirectional conversion between KOReader XPath positions and FreeInkBook character offsets. Uses streaming SAX parsing to match chapter text accounting with ChapterLayout, enabling position sync without requiring DOM or pagination. Handles element ancestry tracking, text offset calculation, and spine index extraction.
40 lines
1.8 KiB
C++
40 lines
1.8 KiB
C++
#pragma once
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// KOReader xpath <-> FreeInkBook character offset, via one streaming SAX pass
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// over the chapter's XHTML (no DOM, no pagination — chapter character offsets
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// are layout-independent, so neither direction needs the page cache).
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//
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// The text accounting mirrors ChapterLayout exactly (suppressed head/style/
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// script/title, body gating, whitespace collapse, <br> newlines, block
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// flushes), so the offsets these functions produce address the same
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// characters the engine's page records anchor on. Known approximation:
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// display:none content is counted here but skipped by layout when the book's
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// CSS hides it — a paragraph-level drift on such books, corrected by the
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// percentage fallback.
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#include <FreeInkBook.h>
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#include <cstdint>
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#include <string>
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namespace BookXPath {
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// Real-ancestry KOReader xpath for a chapter character offset:
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// "/body/DocFragment[N]/body/div[2]/p[4]/text().17". Falls back to the
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// chapter-level "/body/DocFragment[N]" when the offset lies past the text or
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// the parse fails.
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std::string xpathForCharStart(freeink::book::BookSource& source, const freeink::book::ZipCatalog& zip,
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const freeink::book::ZipEntry& entry, int spineIndex, uint32_t charStart);
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// Resolves a KOReader xpath's element ancestry to the chapter character
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// offset where that element's text begins (plus the xpath's text offset).
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// Returns false when the ancestry cannot be matched — caller falls back to
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// the synced percentage.
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bool charStartForXpath(freeink::book::BookSource& source, const freeink::book::ZipCatalog& zip,
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const freeink::book::ZipEntry& entry, const std::string& xpath, uint32_t* charStartOut);
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// The 0-based spine index from "/body/DocFragment[N]/...", or -1.
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int spineIndexForXpath(const std::string& xpath);
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} // namespace BookXPath
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