Parser EPUB in C++: ZIP minimale (STORE/DEFLATE via zlib), container/OPF/spine, TOC EPUB2+3, chiavi segno — testato su EPUB di esempio

This commit is contained in:
2026-08-12 14:18:40 +02:00
parent 9d8bd03990
commit ae15c39421
3 changed files with 478 additions and 2 deletions
+6 -2
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@@ -9,13 +9,17 @@ SOURCES += \
src/settings.cpp \
src/apiclient.cpp \
src/downloader.cpp \
src/opdsparser.cpp
src/opdsparser.cpp \
src/epub.cpp
HEADERS += \
src/settings.h \
src/apiclient.h \
src/downloader.h \
src/opdsparser.h
src/opdsparser.h \
src/epub.h
LIBS += -lz
OTHER_FILES += \
qml/harbour-calibreweb.qml \
+421
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@@ -0,0 +1,421 @@
#include "epub.h"
#include <QDir>
#include <QFile>
#include <QHash>
#include <QStringList>
#include <QXmlStreamReader>
#include <zlib.h>
#include <cstring>
// ---------------------------------------------------------------------------
// Lettore ZIP minimale (solo STORE e DEFLATE, niente crittografia)
// ---------------------------------------------------------------------------
namespace {
struct ZipEntry
{
QString name;
quint16 method;
quint32 compSize;
quint32 uncompSize;
quint32 localOffset;
};
quint16 le16(const QByteArray &d, int off)
{
return (quint8)d.at(off) | ((quint8)d.at(off + 1) << 8);
}
quint32 le32(const QByteArray &d, int off)
{
return (quint32)(quint8)d.at(off)
| ((quint32)(quint8)d.at(off + 1) << 8)
| ((quint32)(quint8)d.at(off + 2) << 16)
| ((quint32)(quint8)d.at(off + 3) << 24);
}
bool readZipEntries(const QByteArray &data, QList<ZipEntry> *entries)
{
// EOCD: cerca la firma PK\x05\x06 negli ultimi 64 KB + commento
const int eocdMax = qMin(data.size(), 65557);
int eocd = -1;
for (int i = data.size() - eocdMax; i <= data.size() - 22; ++i) {
if (data.at(i) == 'P' && data.at(i + 1) == 'K'
&& data.at(i + 2) == '\x05' && data.at(i + 3) == '\x06') {
eocd = i;
break;
}
}
if (eocd < 0)
return false;
const quint32 cdOffset = le32(data, eocd + 16);
const quint16 cdCount = le16(data, eocd + 10);
int off = cdOffset;
for (int i = 0; i < cdCount; ++i) {
if (off + 46 > data.size()
|| data.at(off) != 'P' || data.at(off + 1) != 'K'
|| data.at(off + 2) != '\x01' || data.at(off + 3) != '\x02')
return false;
ZipEntry e;
e.method = le16(data, off + 10);
e.compSize = le32(data, off + 20);
e.uncompSize = le32(data, off + 24);
const quint16 nameLen = le16(data, off + 28);
const quint16 extraLen = le16(data, off + 30);
const quint16 commentLen = le16(data, off + 32);
e.localOffset = le32(data, off + 42);
e.name = QString::fromUtf8(data.mid(off + 46, nameLen));
entries->append(e);
off += 46 + nameLen + extraLen + commentLen;
}
return true;
}
QByteArray extractEntryData(const QByteArray &data, const ZipEntry &e)
{
if ((int)e.localOffset + 30 > data.size())
return QByteArray();
const int lo = e.localOffset;
if (data.at(lo) != 'P' || data.at(lo + 1) != 'K'
|| data.at(lo + 2) != '\x03' || data.at(lo + 3) != '\x04')
return QByteArray();
const quint16 nameLen = le16(data, lo + 26);
const quint16 extraLen = le16(data, lo + 28);
const int dataOff = lo + 30 + nameLen + extraLen;
if (dataOff + (int)e.compSize > data.size())
return QByteArray();
const QByteArray raw = data.mid(dataOff, e.compSize);
if (e.method == 0) // STORE
return raw;
if (e.method == 8) { // DEFLATE (raw, senza header zlib)
QByteArray out;
out.resize(e.uncompSize);
z_stream zs;
std::memset(&zs, 0, sizeof(zs));
if (inflateInit2(&zs, -15) != Z_OK)
return QByteArray();
zs.next_in = reinterpret_cast<Bytef *>(const_cast<char *>(raw.constData()));
zs.avail_in = raw.size();
zs.next_out = reinterpret_cast<Bytef *>(out.data());
zs.avail_out = out.size();
const int r = inflate(&zs, Z_FINISH);
inflateEnd(&zs);
if (r != Z_STREAM_END)
return QByteArray();
out.resize(zs.total_out);
return out;
}
return QByteArray(); // metodo non supportato
}
QString readTextFile(const QString &path)
{
QFile f(path);
if (!f.open(QIODevice::ReadOnly))
return QString();
return QString::fromUtf8(f.readAll());
}
} // namespace
// ---------------------------------------------------------------------------
// EpubBook
// ---------------------------------------------------------------------------
EpubBook::EpubBook()
{
}
EpubBook::~EpubBook()
{
close();
}
void EpubBook::close()
{
if (!m_baseDir.isEmpty()) {
QDir(m_baseDir).removeRecursively();
m_baseDir.clear();
}
m_chapters.clear();
m_title.clear();
m_author.clear();
}
bool EpubBook::open(const QString &epubPath)
{
close();
m_opfDir.clear();
QFile f(epubPath);
if (!f.open(QIODevice::ReadOnly))
return false;
const QByteArray data = f.readAll();
f.close();
QList<ZipEntry> entries;
if (!readZipEntries(data, &entries))
return false;
m_baseDir = QDir::tempPath() + QStringLiteral("/harbour-calibreweb/books/")
+ QString::number(qHash(epubPath), 16);
if (!QDir().mkpath(m_baseDir))
return false;
// estrai tutto (skip directory e path traversal)
for (const ZipEntry &e : entries) {
if (e.name.endsWith(QLatin1Char('/')) || e.name.contains(QStringLiteral("..")))
continue;
const QByteArray content = extractEntryData(data, e);
if (content.isNull())
continue;
const QString dest = m_baseDir + QLatin1Char('/') + e.name;
QDir().mkpath(QFileInfo(dest).absolutePath());
QFile out(dest);
if (out.open(QIODevice::WriteOnly)) {
out.write(content);
out.close();
}
}
if (!parseContainer())
return false;
if (!parseOpf())
return false;
return !m_chapters.isEmpty();
}
bool EpubBook::parseContainer()
{
QFile f(m_baseDir + QStringLiteral("/META-INF/container.xml"));
if (!f.open(QIODevice::ReadOnly))
return false;
QXmlStreamReader r(&f);
while (!r.atEnd() && !r.hasError()) {
if (r.readNextStartElement() && r.name() == QLatin1String("rootfile")) {
const QString fullPath = r.attributes().value(QLatin1String("full-path")).toString();
if (!fullPath.isEmpty()) {
// path RELATIVO alla root epub, non assoluto rispetto alla CWD
m_opfDir = QFileInfo(fullPath).path();
if (m_opfDir == QStringLiteral("."))
m_opfDir.clear();
return true;
}
}
}
return false;
}
QString EpubBook::absolutePath(const QString &relativeToOpfDir) const
{
QString rel = relativeToOpfDir;
rel.replace(QLatin1Char('\\'), QLatin1Char('/'));
if (rel.contains(QLatin1String("..")))
return QString();
if (!m_opfDir.isEmpty())
rel = m_opfDir + QLatin1Char('/') + rel;
return QDir(m_baseDir).filePath(rel);
}
bool EpubBook::parseOpf()
{
QFile f(absolutePath(QStringLiteral("content.opf")));
if (!f.exists())
f.setFileName(absolutePath(QStringLiteral("package.opf")));
if (!f.open(QIODevice::ReadOnly))
return false;
QXmlStreamReader r(&f);
// manifest: id -> {href, media-type, properties}
QHash<QString, QString> manifestHref;
QHash<QString, QString> manifestType;
QHash<QString, QString> manifestProps;
// spine: idrefs in ordine
QStringList spine;
QString navItemId;
QString ncxItemId;
while (!r.atEnd() && !r.hasError()) {
const QXmlStreamReader::TokenType t = r.readNext();
if (t != QXmlStreamReader::StartElement)
continue;
const QStringRef name = r.name();
const QXmlStreamAttributes a = r.attributes();
if (name == QLatin1String("title") && m_title.isEmpty()) {
m_title = r.readElementText().trimmed();
} else if (name == QLatin1String("creator") && m_author.isEmpty()) {
m_author = r.readElementText().trimmed();
} else if (name == QLatin1String("item")) {
const QString id = a.value(QLatin1String("id")).toString();
manifestHref.insert(id, a.value(QLatin1String("href")).toString());
manifestType.insert(id, a.value(QLatin1String("media-type")).toString());
const QString props = a.value(QLatin1String("properties")).toString();
manifestProps.insert(id, props);
if (props.contains(QLatin1String("nav")))
navItemId = id;
if (a.value(QLatin1String("media-type")).toString()
== QLatin1String("application/x-dtbncx+xml"))
ncxItemId = id;
} else if (name == QLatin1String("itemref")) {
spine.append(a.value(QLatin1String("idref")).toString());
}
}
if (spine.isEmpty() || manifestHref.isEmpty())
return false;
// TOC: EPUB3 nav oppure EPUB2 NCX
if (!navItemId.isEmpty())
parseTocEpub3(absolutePath(manifestHref.value(navItemId)));
else if (!ncxItemId.isEmpty())
parseTocEpub2(absolutePath(manifestHref.value(ncxItemId)));
// mappa path assoluto -> titolo dal TOC
QHash<QString, QString> titleByPath;
for (const EpubChapter &c : m_chapters)
titleByPath.insert(c.path, c.title);
m_chapters.clear();
// costruisci i capitoli nell'ordine dello spine
int n = 0;
for (const QString &idref : spine) {
const QString href = manifestHref.value(idref);
if (href.isEmpty())
continue;
const QString abs = absolutePath(href);
if (abs.isEmpty() || !QFile::exists(abs))
continue;
EpubChapter c;
c.id = idref;
c.path = abs;
c.title = titleByPath.value(abs);
if (c.title.isEmpty())
c.title = QStringLiteral("Capitolo ") + QString::number(n + 1);
m_chapters.append(c);
++n;
}
return true;
}
void EpubBook::parseTocEpub3(const QString &navPath)
{
QFile f(navPath);
if (!f.open(QIODevice::ReadOnly))
return;
QXmlStreamReader r(&f);
bool inTocNav = false;
int depth = 0;
while (!r.atEnd() && !r.hasError()) {
const QXmlStreamReader::TokenType t = r.readNext();
if (t == QXmlStreamReader::StartElement) {
const QStringRef name = r.name();
if (name == QLatin1String("nav")) {
if (!inTocNav) {
const QString type = r.attributes()
.value(QLatin1String("http://www.idpf.org/2007/ops"),
QLatin1String("type")).toString();
if (type != QLatin1String("toc"))
continue;
inTocNav = true;
}
++depth;
continue;
}
if (!inTocNav || depth == 0)
continue;
if (name == QLatin1String("a")) {
const QString href = r.attributes().value(QLatin1String("href")).toString();
const QString text = r.readElementText().trimmed();
if (!href.isEmpty() && !text.isEmpty()) {
EpubChapter c;
c.path = absolutePath(href);
c.title = text;
m_chapters.append(c);
}
}
} else if (t == QXmlStreamReader::EndElement && r.name() == QLatin1String("nav")) {
if (inTocNav && --depth <= 0)
break;
}
}
}
void EpubBook::parseTocEpub2(const QString &ncxPath)
{
QFile f(ncxPath);
if (!f.open(QIODevice::ReadOnly))
return;
QXmlStreamReader r(&f);
EpubChapter pending;
bool havePending = false;
while (!r.atEnd() && !r.hasError()) {
const QXmlStreamReader::TokenType t = r.readNext();
if (t == QXmlStreamReader::StartElement) {
const QStringRef name = r.name();
if (name == QLatin1String("navPoint")) {
// nel NCX il <text> (titolo) viene PRIMA del <content> (src):
// accumula in pending e chiudi alla fine del navPoint
pending = EpubChapter();
havePending = true;
} else if (name == QLatin1String("text")) {
if (havePending)
pending.title = r.readElementText().trimmed();
} else if (name == QLatin1String("content")) {
const QString src = r.attributes().value(QLatin1String("src")).toString();
if (havePending)
pending.path = absolutePath(src);
}
} else if (t == QXmlStreamReader::EndElement
&& r.name() == QLatin1String("navPoint")) {
if (havePending && !pending.path.isEmpty())
m_chapters.append(pending);
havePending = false;
}
}
}
QString EpubBook::chapterFilePath(int index) const
{
if (index < 0 || index >= m_chapters.size())
return QString();
return m_chapters.at(index).path;
}
QString EpubBook::chapterTitle(int index) const
{
if (index < 0 || index >= m_chapters.size())
return QString();
return m_chapters.at(index).title;
}
QString EpubBook::makeBookmarkKey(int chapterIndex, double fraction) const
{
return QStringLiteral("cw:v1:%1:%2").arg(chapterIndex).arg(fraction, 0, 'f', 4);
}
bool EpubBook::parseBookmarkKey(const QString &key, int *chapterIndex, double *fraction) const
{
const QStringList parts = key.split(QLatin1Char(':'));
if (parts.size() != 4 || parts.at(0) != QLatin1String("cw")
|| parts.at(1) != QLatin1String("v1"))
return false;
bool okChapter = false, okFrac = false;
const int ch = parts.at(2).toInt(&okChapter);
const double fr = parts.at(3).toDouble(&okFrac);
if (!okChapter || !okFrac)
return false;
if (chapterIndex)
*chapterIndex = ch;
if (fraction)
*fraction = fr;
return true;
}
+51
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@@ -0,0 +1,51 @@
#ifndef EPUB_H
#define EPUB_H
#include <QList>
#include <QString>
struct EpubChapter
{
QString id;
QString path; // path assoluto del file HTML estratto
QString title;
};
class EpubBook
{
public:
EpubBook();
~EpubBook();
bool open(const QString &epubPath);
void close();
QString title() const { return m_title; }
QString author() const { return m_author; }
QList<EpubChapter> chapters() const { return m_chapters; }
QString baseDir() const { return m_baseDir; }
int chapterCount() const { return m_chapters.size(); }
QString chapterFilePath(int index) const;
QString chapterTitle(int index) const;
// chiave segno locale, es. "cw:v1:3:0.42" (capitolo 3, 42% del capitolo)
QString makeBookmarkKey(int chapterIndex, double fraction) const;
bool parseBookmarkKey(const QString &key, int *chapterIndex, double *fraction) const;
private:
bool extractZip(const QString &epubPath);
bool parseContainer();
bool parseOpf();
void parseTocEpub3(const QString &navPath);
void parseTocEpub2(const QString &ncxPath);
QString absolutePath(const QString &relativeToOpfDir) const;
QString m_baseDir;
QString m_opfDir;
QString m_title;
QString m_author;
QList<EpubChapter> m_chapters;
};
#endif // EPUB_H