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Extract EPUB TOC into temp file before parsing (#85)

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## Summary

* Extract EPUB TOC into temp file before parsing
* Streaming ZIP -> XML parser uses up a lot of memory as we're
allocating inflation buffers while also holding a few copies of the
buffer in different forms
* Instead, but streaming the inflated file down to the SD card (like we
do for HTML parsing, we can lower memory usage)

## Additional Context

* This should help with
https://github.com/daveallie/crosspoint-reader/issues/60 and
https://github.com/daveallie/crosspoint-reader/issues/10. It won't
remove those class of issues completely, but will allow for many more
books to be opened.
This commit is contained in:
Dave Allie
2025-12-21 17:08:34 +11:00
committed by GitHub
parent 0d32d21d75
commit f264efdb12
4 changed files with 31 additions and 16 deletions
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36
lib/Epub/Epub.cpp
View File

@@ -93,24 +93,42 @@ bool Epub::parseTocNcxFile() {
Serial.printf("[%lu] [EBP] Parsing toc ncx file: %s\n", millis(), tocNcxItem.c_str());
size_t tocSize;
if (!getItemSize(tocNcxItem, &tocSize)) {
Serial.printf("[%lu] [EBP] Could not get size of toc ncx\n", millis());
return false;
}
const auto tmpNcxPath = getCachePath() + "/toc.ncx";
File tempNcxFile = SD.open(tmpNcxPath.c_str(), FILE_WRITE);
readItemContentsToStream(tocNcxItem, tempNcxFile, 1024);
tempNcxFile.close();
tempNcxFile = SD.open(tmpNcxPath.c_str(), FILE_READ);
const auto ncxSize = tempNcxFile.size();
TocNcxParser ncxParser(contentBasePath, tocSize);
TocNcxParser ncxParser(contentBasePath, ncxSize);
if (!ncxParser.setup()) {
Serial.printf("[%lu] [EBP] Could not setup toc ncx parser\n", millis());
return false;
}
if (!readItemContentsToStream(tocNcxItem, ncxParser, 1024)) {
Serial.printf("[%lu] [EBP] Could not read toc ncx stream\n", millis());
const auto ncxBuffer = static_cast<uint8_t*>(malloc(1024));
if (!ncxBuffer) {
Serial.printf("[%lu] [EBP] Could not allocate memory for toc ncx parser\n", millis());
return false;
}
while (tempNcxFile.available()) {
const auto readSize = tempNcxFile.read(ncxBuffer, 1024);
const auto processedSize = ncxParser.write(ncxBuffer, readSize);
if (processedSize != readSize) {
Serial.printf("[%lu] [EBP] Could not process all toc ncx data\n", millis());
free(ncxBuffer);
tempNcxFile.close();
return false;
}
}
free(ncxBuffer);
tempNcxFile.close();
SD.remove(tmpNcxPath.c_str());
this->toc = std::move(ncxParser.toc);
Serial.printf("[%lu] [EBP] Parsed %d TOC items\n", millis(), this->toc.size());
@@ -293,7 +311,7 @@ std::string& Epub::getSpineItem(const int spineIndex) {
}
EpubTocEntry& Epub::getTocItem(const int tocTndex) {
static EpubTocEntry emptyEntry("", "", "", 0);
static EpubTocEntry emptyEntry = {};
if (toc.empty()) {
Serial.printf("[%lu] [EBP] getTocItem called but toc is empty\n", millis());
return emptyEntry;