iff: Support ILBM (PBM)

It's another variant of IFF where the pixel data is stored
contiguously rather than interleaved.

CMakeLists.txt

@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.16)
 
-set(KF_VERSION "6.16.0") # handled by release scripts
+set(KF_VERSION "6.17.0") # handled by release scripts
 set(KF_DEP_VERSION "6.16.0") # handled by release scripts
 project(KImageFormats VERSION ${KF_VERSION})
 

src/imageformats/chunks.cpp

@@ -10,6 +10,8 @@
 
 #include <QDebug>
 
+#define RECURSION_PROTECTION 10
+
 IFFChunk::~IFFChunk()
 {
 
@@ -20,6 +22,7 @@ IFFChunk::IFFChunk()
     , _size{0}
     , _align{2}
     , _dataPos{0}
+    , _recursionCnt{0}
 {
 }
 
@@ -49,12 +52,16 @@ qint32 IFFChunk::alignBytes() const
 bool IFFChunk::readStructure(QIODevice *d)
 {
     auto ok = readInfo(d);
-    ok = ok && innerReadStructure(d);
+    if (recursionCounter() > RECURSION_PROTECTION - 1) {
+        ok = ok && IFFChunk::innerReadStructure(d); // force default implementation (no more recursion)
+    } else {
+        ok = ok && innerReadStructure(d);
+    }
     if (ok) {
         auto pos = _dataPos + _size;
         if (auto align = pos % alignBytes())
             pos += alignBytes() - align;
-        ok = d->seek(pos);
+        ok = pos < d->pos() ? false : d->seek(pos);
     }
     return ok;
 }
@@ -169,7 +176,17 @@ void IFFChunk::setChunks(const ChunkList &chunks)
     _chunks = chunks;
 }
 
-IFFChunk::ChunkList IFFChunk::innerFromDevice(QIODevice *d, bool *ok, qint32 alignBytes)
+qint32 IFFChunk::recursionCounter() const
+{
+    return _recursionCnt;
+}
+
+void IFFChunk::setRecursionCounter(qint32 cnt)
+{
+    _recursionCnt = cnt;
+}
+
+IFFChunk::ChunkList IFFChunk::innerFromDevice(QIODevice *d, bool *ok, qint32 alignBytes, qint32 recursionCnt)
 {
     auto tmp = false;
     if (ok == nullptr) {
@@ -181,6 +198,10 @@ IFFChunk::ChunkList IFFChunk::innerFromDevice(QIODevice *d, bool *ok, qint32 ali
         return {};
     }
 
+    if (recursionCnt > RECURSION_PROTECTION) {
+        return {};
+    }
+
     IFFChunk::ChunkList list;
     for (; !d->atEnd();) {
         auto cid = d->peek(4);
@@ -229,6 +250,7 @@ IFFChunk::ChunkList IFFChunk::innerFromDevice(QIODevice *d, bool *ok, qint32 ali
             chunk->setAlignBytes(alignBytes);
         }
 
+        chunk->setRecursionCounter(recursionCnt + 1);
         if (!chunk->readStructure(d)) {
             *ok = false;
             return {};
@@ -243,7 +265,7 @@ IFFChunk::ChunkList IFFChunk::innerFromDevice(QIODevice *d, bool *ok, qint32 ali
 
 IFFChunk::ChunkList IFFChunk::fromDevice(QIODevice *d, bool *ok)
 {
-    return innerFromDevice(d, ok, 2);
+    return innerFromDevice(d, ok, 2, 0);
 }
 
 
@@ -525,9 +547,9 @@ bool BODYChunk::isValid() const
     return chunkId() == BODYChunk::defaultChunkId();
 }
 
-QByteArray BODYChunk::strideRead(QIODevice *d, const BMHDChunk *header, const CAMGChunk *camg, const CMAPChunk *cmap) const
+QByteArray BODYChunk::strideRead(QIODevice *d, const FORMChunk *form, const BMHDChunk *header, const CAMGChunk *camg, const CMAPChunk *cmap) const
 {
-    if (!isValid() || header == nullptr) {
+    if (!isValid() || form == nullptr || header == nullptr) {
         return {};
     }
 
@@ -549,7 +571,11 @@ QByteArray BODYChunk::strideRead(QIODevice *d, const BMHDChunk *header, const CA
 
     auto planes = _readBuffer.left(readSize);
     _readBuffer.remove(0, readSize);
-    return BODYChunk::deinterleave(planes, header, camg, cmap);
+    if (form->formType() == FORMChunk::FormType::Pbm) {
+        return planes;
+    } else {
+        return BODYChunk::deinterleave(planes, header, camg, cmap);
+    }
 }
 
 bool BODYChunk::resetStrideRead(QIODevice *d) const
@@ -751,15 +777,21 @@ bool FORMChunk::innerReadStructure(QIODevice *d)
     if (bytes() < 4) {
         return false;
     }
-    _type = d->read(4);
+    const auto type = d->read(4);
-    auto ok = true;
+    auto ok = false;
-    if (_type == QByteArray("ILBM")) {
+    if (type == QByteArrayLiteral("ILBM")) {
-        setChunks(IFFChunk::innerFromDevice(d, &ok, alignBytes()));
+        _type = FormType::Ilbm;
+    } else if (type == QByteArrayLiteral("PBM ")) {
+        _type = FormType::Pbm;
+    }
+
+    if (_type != FormType::Unknown) {
+        setChunks(IFFChunk::innerFromDevice(d, &ok, alignBytes(), recursionCounter()));
     }
     return ok;
 }
 
-QByteArray FORMChunk::formType() const
+FORMChunk::FormType FORMChunk::formType() const
 {
     return _type;
 }
@@ -857,9 +889,9 @@ bool FOR4Chunk::innerReadStructure(QIODevice *d)
     _type = d->read(4);
     auto ok = true;
     if (_type == QByteArray("CIMG")) {
-        setChunks(IFFChunk::innerFromDevice(d, &ok, alignBytes()));
+        setChunks(IFFChunk::innerFromDevice(d, &ok, alignBytes(), recursionCounter()));
     } else if (_type == QByteArray("TBMP")) {
-        setChunks(IFFChunk::innerFromDevice(d, &ok, alignBytes()));
+        setChunks(IFFChunk::innerFromDevice(d, &ok, alignBytes(), recursionCounter()));
     }
     return ok;
 }

src/imageformats/chunks_p.h

@@ -256,6 +256,14 @@ protected:
      */
     void setChunks(const ChunkList &chunks);
 
+    /*!
+     * \brief recursionCounter
+     * Protection against stack overflow due to broken data.
+     * \return The current recursion counter.
+     */
+    qint32 recursionCounter() const;
+    void setRecursionCounter(qint32 cnt);
+
     inline quint16 ui16(quint8 c1, quint8 c2) const {
         return (quint16(c2) << 8) | quint16(c1);
     }
@@ -272,7 +280,7 @@ protected:
         return qint32(ui32(c1, c2, c3, c4));
     }
 
-    static ChunkList innerFromDevice(QIODevice *d, bool *ok, qint32 alignBytes);
+    static ChunkList innerFromDevice(QIODevice *d, bool *ok, qint32 alignBytes, qint32 recursionCnt);
 
 private:
     char _chunkId[4];
@@ -287,6 +295,8 @@ private:
 
     ChunkList _chunks;
 
+    qint32 _recursionCnt;
+
 
 };
 
@@ -441,6 +451,7 @@ protected:
     virtual bool innerReadStructure(QIODevice *d) override;
 };
 
+class FORMChunk;
 
 /*!
  * \brief The BODYChunk class
@@ -466,7 +477,7 @@ public:
      * \return The scanline as requested for QImage.
      * \warning Call resetStrideRead() once before this one.
      */
-    QByteArray strideRead(QIODevice *d, const BMHDChunk *header, const CAMGChunk *camg = nullptr, const CMAPChunk *cmap = nullptr) const;
+    QByteArray strideRead(QIODevice *d, const FORMChunk *form, const BMHDChunk *header, const CAMGChunk *camg = nullptr, const CMAPChunk *cmap = nullptr) const;
 
     /*!
      * \brief resetStrideRead
@@ -490,9 +501,13 @@ private:
  */
 class FORMChunk : public IFFChunk
 {
-    QByteArray _type;
-
 public:
+    enum class FormType {
+        Unknown,
+        Ilbm,
+        Pbm,
+    };
+
     virtual ~FORMChunk() override;
     FORMChunk();
     FORMChunk(const FORMChunk& other) = default;
@@ -502,7 +517,7 @@ public:
 
     bool isSupported() const;
 
-    QByteArray formType() const;
+    FormType formType() const;
 
     QImage::Format format() const;
 
@@ -512,8 +527,10 @@ public:
 
 protected:
     virtual bool innerReadStructure(QIODevice *d) override;
-};
 
+private:
+    FormType _type = FormType::Unknown;
+};
 
 /*!
  * \brief The FOR4Chunk class

src/imageformats/iff.cpp

@@ -74,7 +74,7 @@ IFFHandler::IFFHandler()
 bool IFFHandler::canRead() const
 {
     if (canRead(device())) {
-        setFormat("iff");
+        setFormat("iff"); // TODO ilbm based on header?
         return true;
     }
     return false;
@@ -192,7 +192,7 @@ bool IFFHandler::readStandardImage(QImage *image)
         }
         for (auto y = 0, h = img.height(); y < h; ++y) {
             auto line = reinterpret_cast<char*>(img.scanLine(y));
-            auto ba = body->strideRead(device(), header, camg, cmap);
+            auto ba = body->strideRead(device(), form, header, camg, cmap);
             if (ba.isEmpty()) {
                 qCWarning(LOG_IFFPLUGIN) << "IFFHandler::readStandardImage() error while reading image scanline";
                 return false;
@@ -334,7 +334,7 @@ QVariant IFFHandler::option(ImageOption option) const
 
 QImageIOPlugin::Capabilities IFFPlugin::capabilities(QIODevice *device, const QByteArray &format) const
 {
-    if (format == "iff") {
+    if (format == "iff" || format == "ilbm") {
         return Capabilities(CanRead);
     }
     if (!format.isEmpty()) {

src/imageformats/iff.json

@@ -1,4 +1,4 @@
 {
-    "Keys": [ "iff" ],
+    "Keys": [ "iff", "ilbm" ],
-    "MimeTypes": [ "application/x-iff" ]
+    "MimeTypes": [ "application/x-iff", "application/x-ilbm" ]
 }