EXR: support for metadata saved by Photoshop

src/imageformats/photoshop.cpp

@@ -0,0 +1,140 @@
+/*
+    This file is part of the KDE project
+    SPDX-FileCopyrightText: 2026 Mirco Miranda <[email protected]>
+
+    SPDX-License-Identifier: LGPL-2.1-or-later
+*/
+#include "photoshop_p.h"
+#include "util_p.h"
+
+#include <QLoggingCategory>
+
+#ifdef QT_DEBUG
+Q_LOGGING_CATEGORY(LOG_PSDSHARED, "kf.imageformats.plugins.psdshared", QtDebugMsg)
+#else
+Q_LOGGING_CATEGORY(LOG_PSDSHARED, "kf.imageformats.plugins.psdshared", QtWarningMsg)
+#endif
+
+QString readPascalString(QDataStream &s, qint32 alignBytes, qint32 *size)
+{
+    qint32 tmp = 0;
+    if (size == nullptr)
+        size = &tmp;
+
+    quint8 stringSize;
+    s >> stringSize;
+    *size = sizeof(stringSize);
+
+    QString str;
+    if (stringSize > 0) {
+        QByteArray ba;
+        ba.resize(stringSize);
+        auto read = s.readRawData(ba.data(), ba.size());
+        if (read > 0) {
+            *size += read;
+            str = QString::fromLatin1(ba);
+        }
+    }
+
+    // align
+    if (alignBytes > 1)
+        if (auto pad = *size % alignBytes)
+            *size += s.skipRawData(alignBytes - pad);
+
+    return str;
+}
+
+PSDImageResourceSection readImageResourceSection(QDataStream &s, bool *ok)
+{
+    PSDImageResourceSection irs;
+
+    bool tmp = true;
+    if (ok == nullptr)
+        ok = &tmp;
+    *ok = true;
+
+    // Section size
+    quint32 tmpSize;
+    s >> tmpSize;
+    qint64 sectioSize = tmpSize;
+
+    // Reading Image resource block
+    for (auto size = sectioSize; size > 0;) {
+
+#define DEC_SIZE(value) \
+        if ((size -= qint64(value)) < 0) { \
+                *ok = false; \
+                break; }
+
+        // Length      Description
+        // -------------------------------------------------------------------
+        // 4           Signature: '8BIM'
+        // 2           Unique identifier for the resource. Image resource IDs
+        //             contains a list of resource IDs used by Photoshop.
+        // Variable    Name: Pascal string, padded to make the size even
+        //             (a null name consists of two bytes of 0)
+        // 4           Actual size of resource data that follows
+        // Variable    The resource data, described in the sections on the
+        //             individual resource types. It is padded to make the size
+        //             even.
+
+        quint32 signature;
+        s >> signature;
+        DEC_SIZE(sizeof(signature))
+        // NOTE: MeSa signature is not documented but found in some old PSD take from Photoshop 7.0 CD.
+        if (signature != S_8BIM && signature != S_MeSa) { // 8BIM and MeSa
+            qCDebug(LOG_PSDSHARED) << "Invalid Image Resource Block Signature!";
+            *ok = false;
+            break;
+        }
+
+        // id
+        quint16 id;
+        s >> id;
+        DEC_SIZE(sizeof(id))
+
+        // getting data
+        PSDImageResourceBlock irb;
+
+        // name
+        qint32 bytes = 0;
+        irb.name = readPascalString(s, 2, &bytes);
+        DEC_SIZE(bytes)
+
+        // data read
+        quint32 dataSize;
+        s >> dataSize;
+        DEC_SIZE(sizeof(dataSize))
+        if (auto dev = s.device()) {
+            if (dataSize > size) {
+                qCDebug(LOG_PSDSHARED) << "Invalid Image Resource Block Data Size!";
+                *ok = false;
+                break;
+            }
+            irb.data = deviceRead(dev, dataSize);
+        }
+        auto read = irb.data.size();
+        if (read > 0) {
+            DEC_SIZE(read)
+        }
+        if (read != qint64(dataSize)) {
+            qCDebug(LOG_PSDSHARED) << "Image Resource Block Read Error!";
+            *ok = false;
+            break;
+        }
+
+        if (auto pad = dataSize % 2) {
+            auto skipped = s.skipRawData(pad);
+            if (skipped > 0) {
+                DEC_SIZE(skipped);
+            }
+        }
+
+        // insert IRB
+        irs.insert(ImageResourceId(id), irb);
+
+#undef DEC_SIZE
+    }
+
+    return irs;
+}