Make compression level 0-100

CMakeLists.txt

@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.14)
 
-project(libXISF VERSION 0.2.10 LANGUAGES CXX C
+project(libXISF VERSION 0.2.12 LANGUAGES CXX C
     HOMEPAGE_URL https://gitea.nouspiro.space/nou/libXISF
     DESCRIPTION "LibXISF is C++ library that can read and write XISF files produced by PixInsight.")
 

README.md

@@ -9,7 +9,7 @@ To compile simply run these commands
 ```
 cmake -B build -S .
 cmake --build build --parallel
-cmake --install .
+cmake --install build
 ```
 
 By default it use bundled libraries. If you wish to use external libraries you will may add

libxisf.cpp

@@ -23,6 +23,7 @@
 #include <iostream>
 #include <sstream>
 #include <cstdlib>
+#include <cmath>
 #include <lz4.h>
 #include <lz4hc.h>
 #include <pugixml.hpp>
@@ -49,6 +50,7 @@ static std::unordered_map<Image::ColorSpace, String> colorSpaceToString;
 static DataBlock::CompressionCodec compressionCodecOverride = DataBlock::None;
 static bool byteShuffleOverride = false;
 static int compressionLevelOverride = -1;
+const size_t GiB = 1073741824;
 
 static const std::unordered_map<String, std::pair<String, Variant::Type>> fitsNameToPropertyIdTypeConvert = {
     {"OBSERVER", {"Observer:Name", Variant::Type::String}},
@@ -86,12 +88,12 @@ static void byteShuffle(ByteArray &data, int itemSize)
     {
         ByteArray &input = data;
         ByteArray output(input.size());
-        int num = input.size() / itemSize;
+        size_t num = input.size() / itemSize;
         char *s = output.data();
         for(int i=0; i<itemSize; i++)
         {
             const char *u = input.constData() + i;
-            for(int o=0; o<num; o++, s++, u += itemSize)
+            for(size_t o=0; o<num; o++, s++, u += itemSize)
                 *s = *u;
         }
         memcpy(s, input.constData() + num * itemSize, input.size() % itemSize);
@@ -105,12 +107,12 @@ static void byteUnshuffle(ByteArray &data, int itemSize)
     {
         ByteArray &input = data;
         ByteArray output(input.size());
-        int num = input.size() / itemSize;
+        size_t num = input.size() / itemSize;
         const char *s = input.constData();
         for(int i=0; i<itemSize; i++)
         {
             char *u = output.data() + i;
-            for(int o=0; o<num; o++, s++, u += itemSize)
+            for(size_t o=0; o<num; o++, s++, u += itemSize)
                 *u = *s;
         }
         memcpy(output.data() + num * itemSize, s, input.size() % itemSize);
@@ -127,6 +129,9 @@ void DataBlock::decompress(const ByteArray &input, const String &encoding)
     else if(encoding == "base16")
         tmp.decodeHex();
 
+    if(subblocks.size() == 0)
+        subblocks.push_back({tmp.size(), uncompressedSize});
+
     switch(codec)
     {
     case None:
@@ -135,27 +140,55 @@ void DataBlock::decompress(const ByteArray &input, const String &encoding)
     case Zlib:
     {
         data.resize(uncompressedSize);
-        uLongf size = uncompressedSize;
+        const char *srcPtr = tmp.constData();
-        ::uncompress((Bytef*)data.data(), &size, (Bytef*)tmp.data(), tmp.size());
+        char *dstPtr = data.data();
+        for(auto &block : subblocks)
+        {
+            uLongf size = block.second;
+            ::uncompress((Bytef*)dstPtr, &size, (const Bytef*)srcPtr, block.first);
+            srcPtr += block.first;
+            dstPtr += block.second;
+        }
         break;
     }
     case LZ4:
     case LZ4HC:
+    {
         data.resize(uncompressedSize);
-        if(LZ4_decompress_safe(tmp.constData(), data.data(), tmp.size(), data.size()) < 0)
+        const char *srcPtr = tmp.constData();
-            throw Error("LZ4 decompression failed");
+        char *dstPtr = data.data();
+        for(auto &block : subblocks)
+        {
+            if(LZ4_decompress_safe(srcPtr, dstPtr, block.first, block.second) < 0)
+                throw Error("LZ4 decompression failed");
+            srcPtr += block.first;
+            dstPtr += block.second;
+        }
         break;
+    }
     case ZSTD:
 #ifdef HAVE_ZSTD
+    {
         data.resize(uncompressedSize);
-        if(ZSTD_isError(ZSTD_decompress(data.data(), data.size(), tmp.constData(), tmp.size())))
+        const char *srcPtr = tmp.constData();
-            throw Error("ZSTD decompression failed");
+        char *dstPtr = data.data();
+        for(auto &block : subblocks)
+        {
+            if(ZSTD_isError(ZSTD_decompress(dstPtr, block.second, srcPtr, block.first)))
+                throw Error("ZSTD decompression failed");
+            srcPtr += block.first;
+            dstPtr += block.second;
+        }
+
+    }
 #else
         throw Error("ZSTD support not compiled");
 #endif
         break;
     }
 
+    subblocks.clear();
+
     byteUnshuffle(data, byteShuffling);
     attachmentPos = 0;
 }
@@ -181,26 +214,48 @@ void DataBlock::compress(int sampleFormatSize)
         break;
     case Zlib:
     {
-        data.resize(compressBound(uncompressedSize));
+        int64_t size = tmp.size();
-        uLongf compressedSize = data.size();
+        int64_t compSize = 0;
-        if(::compress2((Bytef*)data.data(), &compressedSize, (Bytef*)tmp.data(), tmp.size(), compressLevel) != Z_OK)
+        int64_t inPtr = 0;
-            throw Error("Zlib compression failed");
+        while(inPtr < size)
-        data.resize(compressedSize);
+        {
+            int64_t inSize = UINT32_MAX < size - inPtr ? UINT32_MAX : size - inPtr;
+            data.resize(compSize + compressBound(inSize));
+            uLongf outSize = data.size() - compSize;
+            if(::compress2((Bytef*)data.data() + compSize, &outSize, (const Bytef*)tmp.constData() + inPtr, inSize, compressLevel) != Z_OK)
+                throw Error("Zlib compression failed");
+
+            compSize += outSize;
+            inPtr += inSize;
+            subblocks.push_back({outSize, inSize});
+        }
+        data.resize(compSize);
         break;
     }
     case LZ4:
     case LZ4HC:
     {
-        int compSize = 0;
+        int64_t size = tmp.size();
-        data.resize(LZ4_compressBound(tmp.size()));
+        int64_t compSize = 0;
-        if(codec == LZ4)
+        int64_t inPtr = 0;
-            compSize = LZ4_compress_default(tmp.constData(), data.data(), tmp.size(), data.size());
+        while(inPtr < size)
-        else
+        {
-            compSize = LZ4_compress_HC(tmp.constData(), data.data(), tmp.size(), data.size(), compressLevel < 0 ? LZ4HC_CLEVEL_DEFAULT : compressLevel);
+            int64_t inSize = LZ4_MAX_INPUT_SIZE < size - inPtr ? LZ4_MAX_INPUT_SIZE : size - inPtr;
+            data.resize(compSize + LZ4_compressBound(inSize));
+            int outSize = 0;
 
-        if(compSize <= 0)
+            if(codec == LZ4)
-            throw Error("LZ4 compression failed");
+                outSize = LZ4_compress_default(tmp.constData() + inPtr, data.data() + compSize, inSize, data.size() - compSize);
+            else
+                outSize = LZ4_compress_HC(tmp.constData() + inPtr, data.data() + compSize, inSize, data.size() - compSize, compressLevel < 0 ? LZ4HC_CLEVEL_DEFAULT : compressLevel);
 
+            if(outSize <= 0)
+                throw Error("LZ4 compression failed");
+
+            compSize += outSize;
+            inPtr += inSize;
+            subblocks.push_back({outSize, inSize});
+        }
         data.resize(compSize);
         break;
     }
@@ -389,6 +444,10 @@ bool Image::addFITSKeywordAsProperty(const String &name, const String &value)
     {
         auto &c = fitsNameToPropertyIdTypeConvert.at(name);
         Property prop(c.first, variantFromString(c.second, value));
+
+        if(name == "APTDIA" || name == "FOCALLEN")
+            prop.value.value<LibXISF::Float32>() /= 1000.0f;
+
         updateProperty(prop);
         return true;
     }
@@ -428,7 +487,38 @@ DataBlock::CompressionCodec Image::compression() const
 void Image::setCompression(DataBlock::CompressionCodec compression, int level)
 {
     _dataBlock.codec = compression;
-    _dataBlock.compressLevel = level;
+    _dataBlock.compressLevel = -1;
+
+    level = std::min(std::max(level, -1), 100);
+
+    auto percentToRange = [](int val, int min, int max)
+    {
+        double slope = (max - min) / 100.0;
+        return std::round(min + slope * val);
+    };
+
+    if(level >= 0)
+    {
+        switch(compression)
+        {
+        case DataBlock::CompressionCodec::Zlib:
+            _dataBlock.compressLevel = percentToRange(level, Z_BEST_SPEED, Z_BEST_COMPRESSION);
+            break;
+        case DataBlock::CompressionCodec::LZ4:
+        case DataBlock::CompressionCodec::LZ4HC:
+            _dataBlock.compressLevel = percentToRange(level, 1, LZ4HC_CLEVEL_MAX);
+            break;
+        case DataBlock::CompressionCodec::ZSTD:
+#ifdef HAVE_ZSTD
+            _dataBlock.compressLevel = percentToRange(level, ZSTD_minCLevel(), ZSTD_maxCLevel());
+#endif
+            break;
+        default:
+            //nothing
+            break;
+        }
+    }
+
 }
 
 bool Image::byteShuffling() const
@@ -707,7 +797,7 @@ void XISFReaderPrivate::parseCompression(const pugi::xml_node &node, DataBlock &
         else
             throw Error("Unknown compression codec");
 
-        dataBlock.uncompressedSize = std::stoul(compression[1]);
+        dataBlock.uncompressedSize = std::stoull(compression[1]);
 
         if(compression[0].find("+sh") != std::string::npos)
         {
@@ -716,6 +806,18 @@ void XISFReaderPrivate::parseCompression(const pugi::xml_node &node, DataBlock &
             else
                 throw Error("Missing byte shuffling size");
         }
+
+        if(node.attribute("subblocks"))
+        {
+            std::vector<std::string> subblocks = splitString(node.attribute("subblocks").as_string(), ':');
+            for(auto &block : subblocks)
+            {
+                size_t pos = 0;
+                size_t comp = std::stoull(block, &pos);
+                size_t deco = std::stoull(block.substr(pos+1));
+                dataBlock.subblocks.push_back({comp, deco});
+            }
+        }
     }
 }
 
@@ -737,8 +839,8 @@ DataBlock XISFReaderPrivate::parseDataBlock(const pugi::xml_node &node)
     }
     else if(location.size() >= 3 && location[0] == "attachment")
     {
-        dataBlock.attachmentPos = std::stoul(location[1]);
+        dataBlock.attachmentPos = std::stoull(location[1]);
-        dataBlock.attachmentSize = std::stoul(location[2]);
+        dataBlock.attachmentSize = std::stoull(location[2]);
     }
     else
     {
@@ -814,9 +916,9 @@ Image XISFReaderPrivate::parseImage(const pugi::xml_node &node)
 
     std::vector<std::string> geometry = splitString(node.attribute("geometry").as_string(), ':');
     if(geometry.size() != 3)throw Error("We support only 2D images");
-    image._width = std::stoul(geometry[0]);
+    image._width = std::stoull(geometry[0]);
-    image._height = std::stoul(geometry[1]);
+    image._height = std::stoull(geometry[1]);
-    image._channelCount = std::stoul(geometry[2]);
+    image._channelCount = std::stoull(geometry[2]);
     if(!image._width || !image._height || !image._channelCount)throw Error("Invalid image geometry");
 
     std::vector<std::string> bounds = splitString(node.attribute("bounds").as_string(), ':');
@@ -860,7 +962,15 @@ void XISFReaderPrivate::readAttachment(DataBlock &dataBlock)
 {
     ByteArray data(dataBlock.attachmentSize);
     _io->seekg(dataBlock.attachmentPos);
-    _io->read(data.data(), dataBlock.attachmentSize);
+    size_t size = dataBlock.attachmentSize;
+    char *ptr = data.data();
+    while(size > 0)
+    {
+        size_t s = std::min(size, GiB);
+        _io->read(ptr, s);
+        size -= s;
+        ptr += s;
+    }
     dataBlock.decompress(data);
 }
 
@@ -871,13 +981,14 @@ public:
     void save(ByteArray &data);
     void save(std::ostream &io);
     void writeImage(const Image &image);
+    static void writeFITSKeyword(pugi::xml_node &node, const FITSKeyword &keyword);
 private:
     void writeHeader();
     void writeImageElement(pugi::xml_node &node, const Image &image);
     void writeDataBlockAttributes(pugi::xml_node &image_node, const DataBlock &dataBlock);
     void writePropertyElement(pugi::xml_node &node, const Property &property);
-    void writeFITSKeyword(pugi::xml_node &node, const FITSKeyword &keyword);
     void writeMetadata(pugi::xml_node &node);
+    void updateImageAttachmentPos(pugi::xml_node &root, size_t offset);
     ByteArray _xisfHeader;
     ByteArray _attachmentsData;
     std::vector<Image> _images;
@@ -909,7 +1020,15 @@ void XISFWriterPrivate::save(std::ostream &io)
 
     for(auto &image : _images)
     {
-        io.write(image._dataBlock.data.constData(), image._dataBlock.data.size());
+        const char *ptr = image._dataBlock.data.constData();
+        size_t size = image._dataBlock.data.size();
+        while(size > 0)
+        {
+            size_t s = std::min(size, GiB);
+            io.write(ptr, s);
+            ptr += s;
+            size -= s;
+        }
     }
 }
 
@@ -940,25 +1059,26 @@ void XISFWriterPrivate::writeHeader()
 
     writeMetadata(root);
 
-    std::stringstream xml;
+    uint32_t size = 0;
-    xml.write(signature, sizeof(signature));
+    std::string header;
-    doc.save(xml, "", pugi::format_raw);
+    while(true)
-
-    std::string header = xml.str();
-    uint32_t size = header.size();
-
-    uint32_t offset = 0;
-    std::string replace = "attachment:2147483648";
-    for(auto &image : _images)
     {
-        std::string blockPos = std::string("attachment:") + std::to_string(size + offset);
+        std::stringstream xml;
-        size_t pos = header.find(replace, 32);
+        xml.write(signature, sizeof(signature));
-        header.replace(pos, replace.size(), blockPos);
+        doc.save(xml, "", pugi::format_raw);
-        offset += image._dataBlock.data.size();
+        header = xml.str();
+        if(size != header.size())
+        {
+            size = header.size();
+            updateImageAttachmentPos(root, size);
+        }
+        else
+        {
+            break;
+        }
     }
 
     uint32_t headerSize = header.size() - sizeof(signature);
-    header.resize(size, 0);
     header.replace(8, sizeof(uint32_t), (const char*)&headerSize, sizeof(uint32_t));
 
     _xisfHeader = ByteArray(header.c_str(), header.size());
@@ -998,7 +1118,8 @@ void XISFWriterPrivate::writeImageElement(pugi::xml_node &node, const Image &ima
     if(image._iccProfile.size())
     {
         ByteArray base64 = image._iccProfile;
-        base64.decodeBase64();
+        base64.encodeBase64();
+        base64.append('\0');
         pugi::xml_node icc_node = image_node.append_child("ICCProfile");
         icc_node.append_attribute("location").set_value("inline:base64");
         icc_node.append_child(pugi::node_pcdata).set_value(base64.data());
@@ -1017,7 +1138,10 @@ void XISFWriterPrivate::writeDataBlockAttributes(pugi::xml_node &image_node, con
     }
     else
     {
-        std::string attachment = "attachment:2147483648:" + std::to_string(dataBlock.data.size());
+        std::string attachment = "attachment:";
+        if(dataBlock.attachmentPos == 0) attachment += "99999";
+        else attachment += std::to_string(dataBlock.attachmentPos);
+        attachment += ":" + std::to_string(dataBlock.data.size());
         image_node.append_attribute("location").set_value(attachment.c_str());
     }
 
@@ -1047,6 +1171,19 @@ void XISFWriterPrivate::writeDataBlockAttributes(pugi::xml_node &image_node, con
 
         image_node.append_attribute("compression").set_value(codec.c_str());
     }
+
+    if(!dataBlock.subblocks.empty())
+    {
+        std::string subblocks;
+        for(auto i = dataBlock.subblocks.begin(); i != dataBlock.subblocks.end(); i++)
+        {
+            if(i != dataBlock.subblocks.begin())
+                subblocks += ":";
+
+            subblocks += std::to_string(i->first) + "," + std::to_string(i->second);
+        }
+        image_node.append_attribute("subblocks").set_value(subblocks.c_str());
+    }
 }
 
 void XISFWriterPrivate::writePropertyElement(pugi::xml_node &node, const Property &property)
@@ -1077,6 +1214,19 @@ void XISFWriterPrivate::writeMetadata(pugi::xml_node &node)
     writePropertyElement(metadata, Property("XISF:CreatorApplication", "LibXISF"));
 }
 
+void XISFWriterPrivate::updateImageAttachmentPos(pugi::xml_node &root, size_t offset)
+{
+    pugi::xpath_node_set imageNodes = root.select_nodes("//Image");
+    int i = 0;
+    for(auto &image : _images)
+    {
+        pugi::xml_node node = imageNodes[i++].node();
+        std::string location = "attachment:" + std::to_string(offset) + ":" + std::to_string(image._dataBlock.data.size());
+        offset += image._dataBlock.data.size();
+        node.attribute("location").set_value(location.c_str());
+    }
+}
+
 XISFReader::XISFReader()
 {
     p = new XISFReaderPrivate;
@@ -1152,6 +1302,321 @@ void XISFWriter::writeImage(const Image &image)
     p->writeImage(image);
 }
 
+class XISFModifyPrivate
+{
+public:
+    void open(const String &name);
+    void open(const ByteArray &data);
+    /** Open image from istream. This method takes ownership of *io pointer */
+    void open(std::istream *io);
+    /** Close opended file release all data. */
+    void close();
+
+    void save(const String &name);
+    void save(ByteArray &data);
+    void save(std::ostream &io);
+
+    void addFITSKeyword(uint32_t image, const FITSKeyword &keyword);
+    void updateFITSKeyword(uint32_t image, const FITSKeyword &keyword, bool add);
+    void removeFITSKeyword(uint32_t image, const String &name);
+private:
+    void readXISFHeader();
+    void parseAttachmentPos(pugi::xml_node &root);
+    void updateAttachmentPos(pugi::xml_node &root, size_t offset);
+
+    std::unique_ptr<std::istream> _io;
+    std::unique_ptr<StreamBuffer> _buffer;
+
+    pugi::xml_document _doc;
+    pugi::xml_node _root;
+    std::map<int, std::pair<uint64_t, uint64_t>> _attachmentPos;// pair contain position and size
+    std::map<int, std::pair<uint64_t, uint64_t>> _attachmentPosNew;
+};
+
+
+void XISFModifyPrivate::open(const String &name)
+{
+    close();
+    _io = std::make_unique<std::ifstream>(name.c_str(), std::ios_base::in | std::ios_base::binary);
+    readXISFHeader();
+}
+
+void XISFModifyPrivate::open(const ByteArray &data)
+{
+    close();
+    _buffer = std::make_unique<StreamBuffer>(data);
+    _io = std::make_unique<std::istream>(_buffer.get());
+    readXISFHeader();
+}
+
+void XISFModifyPrivate::open(std::istream *io)
+{
+    close();
+    _io.reset(io);
+    readXISFHeader();
+}
+
+void XISFModifyPrivate::close()
+{
+    _io.reset();
+    _buffer.reset();
+    _root = pugi::xml_node();
+    _doc.reset();
+}
+
+void XISFModifyPrivate::save(const String &name)
+{
+    std::ofstream fw(name.c_str(), std::ios_base::out | std::ios_base::binary);
+
+    if(fw.fail())
+        throw Error("Failed to open file");
+
+    save(fw);
+}
+
+void XISFModifyPrivate::save(ByteArray &data)
+{
+    StreamBuffer buffer;
+    std::ostream oss(&buffer);
+    save(oss);
+    data = buffer.byteArray();
+}
+
+void XISFModifyPrivate::save(std::ostream &io)
+{
+    if(!_io || !_root)
+        throw Error("No input file opened");
+
+    const char signature[16] = {'X', 'I', 'S', 'F', '0', '1', '0', '0', 0, 0, 0, 0, 0, 0, 0, 0};
+
+    pugi::xml_document doc;
+    doc.append_child(pugi::node_comment).set_value("\nExtensible Image Serialization Format - XISF version 1.0\nCreated with libXISF - https://nouspiro.space\n");
+    pugi::xml_node root_copy = doc.append_copy(_root);
+
+    uint32_t size = 0;
+    std::string header;
+    while(true)
+    {
+        std::stringstream xml;
+        xml.write(signature, sizeof(signature));
+        doc.save(xml, "", pugi::format_raw);
+        header = xml.str();
+        if(size != header.size())
+        {
+            size = header.size();
+            updateAttachmentPos(root_copy, size);
+        }
+        else
+        {
+            break;
+        }
+    }
+
+    uint32_t headerSize = header.size() - sizeof(signature);
+    header.replace(8, sizeof(uint32_t), (const char*)&headerSize, sizeof(uint32_t));
+
+    io.write(header.c_str(), header.size());
+    const uint64_t BLOCK_SIZE = 1024*1024*4;
+    std::vector<char> data(BLOCK_SIZE);
+    for(auto &pos : _attachmentPos)
+    {
+        uint64_t oldPos = pos.second.first;
+        uint64_t size = pos.second.second;
+
+        _io->seekg(oldPos);
+        while(size)
+        {
+            _io->read(&data[0], std::min(size, BLOCK_SIZE));
+            io.write(&data[0], std::min(size, BLOCK_SIZE));
+            size -= std::min(size, BLOCK_SIZE);
+        }
+    }
+}
+
+void XISFModifyPrivate::addFITSKeyword(uint32_t image, const FITSKeyword &keyword)
+{
+    if(!_root)
+        throw Error("No input file opened");
+
+    pugi::xpath_node_set images = _root.select_nodes("//Image");
+
+    if(image >= images.size())
+        throw Error("Out of bounds");
+
+    pugi::xml_node imageNode = images[image].node();
+    XISFWriterPrivate::writeFITSKeyword(imageNode, keyword);
+}
+
+void XISFModifyPrivate::updateFITSKeyword(uint32_t image, const FITSKeyword &keyword, bool add)
+{
+    if(!_root)
+        throw Error("No input file opened");
+
+    pugi::xpath_node_set images = _root.select_nodes("//Image");
+
+    if(image >= images.size())
+        throw Error("Out of bounds");
+
+    pugi::xpath_variable_set variables;
+    variables.set("name", keyword.name.c_str());
+    pugi::xml_node imageNode = images[image].node();
+    pugi::xml_node keywordNode = imageNode.select_node("FITSKeyword[@name=string($name)]", &variables).node();
+
+    if(keywordNode)
+    {
+        if(keywordNode.attribute("value"))
+            keywordNode.attribute("value").set_value(keyword.value.c_str());
+        else
+            keywordNode.append_attribute("value").set_value(keyword.value.c_str());
+
+        if(keywordNode.attribute("comment"))
+            keywordNode.attribute("comment").set_value(keyword.comment.c_str());
+        else
+            keywordNode.append_attribute("comment").set_value(keyword.comment.c_str());
+    }
+    else if(add)
+    {
+        XISFWriterPrivate::writeFITSKeyword(imageNode, keyword);
+    }
+}
+
+void XISFModifyPrivate::removeFITSKeyword(uint32_t image, const String &name)
+{
+    if(!_root)
+        throw Error("No input file opened");
+
+    pugi::xpath_node_set images = _root.select_nodes("//Image");
+
+    if(image >= images.size())
+        throw Error("Out of bounds");
+
+    pugi::xpath_variable_set variables;
+    variables.set("name", name.c_str());
+    pugi::xml_node imageNode = images[image].node();
+    pugi::xml_node keywordNode = imageNode.select_node("FITSKeyword[@name=string($name)]", &variables).node();
+
+    if(keywordNode)
+        imageNode.remove_child(keywordNode);
+}
+
+void XISFModifyPrivate::readXISFHeader()
+{
+    char signature[8];
+    _io->read(signature, sizeof(signature));
+    if(_io->fail())
+        throw Error("Failed to read from file");
+
+    if(memcmp(signature, "XISF0100", sizeof(signature)) != 0)
+        throw Error("Not valid XISF 1.0 file");
+
+    uint32_t headerLen[2] = {0};
+    _io->read((char*)&headerLen, sizeof(headerLen));
+
+    ByteArray xisfHeader(headerLen[0]);
+    _io->read(xisfHeader.data(), headerLen[0]);
+
+    _doc.load_buffer(xisfHeader.data(), xisfHeader.size());
+
+    _root = _doc.child("xisf");
+
+    parseAttachmentPos(_root);
+
+    if(!_root || _root.attribute("version").as_string() != std::string("1.0"))
+        throw Error("Unknown root XML element");
+}
+
+void XISFModifyPrivate::parseAttachmentPos(pugi::xml_node &root)
+{
+    pugi::xpath_node_set locationAttributes = root.select_nodes("//@location");
+    int i = 0;
+    for(auto &attr : locationAttributes)
+    {
+        std::string locationStr = attr.attribute().as_string();
+        std::vector<std::string> location = splitString(locationStr, ':');
+        if(location.size() >= 3 && location[0] == "attachment")
+        {
+            uint64_t attachmentPos = std::stoull(location[1]);
+            uint64_t attachmentSize = std::stoull(location[2]);
+            _attachmentPos[i] = {attachmentPos, attachmentSize};
+        }
+        i++;
+    }
+}
+
+void XISFModifyPrivate::updateAttachmentPos(pugi::xml_node &root, size_t offset)
+{
+    pugi::xpath_node_set locationAttributes = root.select_nodes("//@location");
+    for(auto &pos : _attachmentPos)
+    {
+        pugi::xml_attribute attr = locationAttributes[pos.first].attribute();
+        uint64_t attachmentSize = pos.second.second;
+        std::string locationStr = "attachment:" + std::to_string(offset) + ":" + std::to_string(attachmentSize);
+        _attachmentPosNew[pos.first] = pos.second;
+        offset += attachmentSize;
+        attr.set_value(locationStr.c_str());
+    }
+}
+
+XISFModify::XISFModify()
+{
+    p = new XISFModifyPrivate();
+}
+
+XISFModify::~XISFModify()
+{
+    delete p;
+}
+
+void XISFModify::open(const String &name)
+{
+    p->open(name);
+}
+
+void XISFModify::open(const ByteArray &data)
+{
+    p->open(data);
+}
+
+void XISFModify::open(std::istream *io)
+{
+    p->open(io);
+}
+
+void XISFModify::close()
+{
+    p->close();
+}
+
+void XISFModify::save(const String &name)
+{
+    p->save(name);
+}
+
+void XISFModify::save(ByteArray &data)
+{
+    p->save(data);
+}
+
+void XISFModify::save(std::ostream &io)
+{
+    p->save(io);
+}
+
+void XISFModify::addFITSKeyword(uint32_t image, const FITSKeyword &keyword)
+{
+    p->addFITSKeyword(image, keyword);
+}
+
+void XISFModify::updateFITSKeyword(uint32_t image, const FITSKeyword &keyword, bool add)
+{
+    p->updateFITSKeyword(image, keyword, add);
+}
+
+void XISFModify::removeFITSKeyword(uint32_t image, const String &name)
+{
+    p->removeFITSKeyword(image, name);
+}
+
 #define STRING_ENUM(map, map2, c, e) { map.insert({#e, c::e}); map2.insert({c::e, #e}); }
 
 struct Init

libxisf.h

@@ -35,6 +35,7 @@ namespace LibXISF
 
 class XISFReaderPrivate;
 class XISFWriterPrivate;
+class XISFModifyPrivate;
 
 class LIBXISF_EXPORT ByteArray
 {
@@ -180,6 +181,7 @@ struct LIBXISF_EXPORT DataBlock
     uint64_t attachmentPos = 0;
     uint64_t attachmentSize = 0;
     uint64_t uncompressedSize = 0;
+    std::vector<std::pair<uint64_t, uint64_t>> subblocks;
     CompressionCodec codec = None;
     int compressLevel = -1;
     ByteArray data;
@@ -315,6 +317,11 @@ public:
     const T* imageData() const { return static_cast<T*>(imageData()); }
     size_t imageDataSize() const;
     DataBlock::CompressionCodec compression() const;
+    /** Set compression type and level.
+     *  @param compression define which compression algorithm to use.
+     *  @param level number between 0 and 100. Zero means lowest compression and maximum speed. Hundred means maximum compression speed.
+     *  -1 means default compression level defined by compression library.
+     */
     void setCompression(DataBlock::CompressionCodec compression, int level = -1);
     bool byteShuffling() const;
     void setByteshuffling(bool enable);
@@ -404,6 +411,42 @@ public:
     const char* what() const noexcept { return _msg.c_str(); }
 };
 
+class LIBXISF_EXPORT XISFModify
+{
+public:
+    XISFModify();
+    virtual ~XISFModify();
+    void open(const String &name);
+    void open(const ByteArray &data);
+    void open(std::istream *io);
+    void close();
+    void save(const String &name);
+    void save(ByteArray &data);
+    void save(std::ostream &io);
+
+    /**
+     * @brief addFITSKeyword append new keyword to image
+     * @param image index of image to update
+     * @param keyword that will be added
+     */
+    void addFITSKeyword(uint32_t image, const FITSKeyword &keyword);
+    /**
+     * @brief updateFITSKeyword update keyword with same name
+     * @param image index of image to update
+     * @param keyword that will be updated
+     * @param add if true then it will add new keyword in case that it doesn't exists
+     */
+    void updateFITSKeyword(uint32_t image, const FITSKeyword &keyword, bool add);
+    /**
+     * @brief removeFITSKeyword remove keyword with name from image
+     * @param image index of image to update
+     * @param name of keyword that will be removed
+     */
+    void removeFITSKeyword(uint32_t image, const String &name);
+private:
+    XISFModifyPrivate *p;
+};
+
 template<typename T>
 constexpr Image::SampleFormat Image::sampleFormatEnum()
 {

streambuffer.cpp

@@ -1,3 +1,21 @@
+/************************************************************************
+ * LibXISF - library to load and save XISF files                        *
+ * Copyright (C) 2024 Dušan Poizl                                       *
+ *                                                                      *
+ * This program is free software: you can redistribute it and/or modify *
+ * it under the terms of the GNU General Public License as published by *
+ * the Free Software Foundation, either version 3 of the License, or    *
+ * (at your option) any later version.                                  *
+ *                                                                      *
+ * This program is distributed in the hope that it will be useful,      *
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of       *
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the        *
+ * GNU General Public License for more details.                         *
+ *                                                                      *
+ * You should have received a copy of the GNU General Public License    *
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.*
+ ************************************************************************/
+
 #include "streambuffer.h"
 
 namespace LibXISF
@@ -89,7 +107,7 @@ std::streamsize StreamBuffer::xsgetn(char_type *s, std::streamsize n)
     std::streamsize len = egptr() - gptr();
     if(len > 0)
     {
-        std::streamsize c = std::min(n, len);
+        std::streamsize c = n < len ? n : len;
         std::memcpy(s, gptr(), c);
         gbump(c);
         ret = c;

streambuffer.h

@@ -1,3 +1,21 @@
+/************************************************************************
+ * LibXISF - library to load and save XISF files                        *
+ * Copyright (C) 2024 Dušan Poizl                                       *
+ *                                                                      *
+ * This program is free software: you can redistribute it and/or modify *
+ * it under the terms of the GNU General Public License as published by *
+ * the Free Software Foundation, either version 3 of the License, or    *
+ * (at your option) any later version.                                  *
+ *                                                                      *
+ * This program is distributed in the hope that it will be useful,      *
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of       *
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the        *
+ * GNU General Public License for more details.                         *
+ *                                                                      *
+ * You should have received a copy of the GNU General Public License    *
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.*
+ ************************************************************************/
+
 #ifndef STREAMBUFFER_H
 #define STREAMBUFFER_H
 

utils.cpp

@@ -52,7 +52,7 @@ void sha1(uint8_t *data, size_t len, uint8_t *hash)
     nlen += 64 - nlen % 64;
     tmp.resize(nlen, 0);
 
-    size_t ml = len * 8;
+    uint64_t ml = len * 8;
     tmp[nlen - 1] = ml & 0xff;
     tmp[nlen - 2] = ml >>  8 & 0xff;
     tmp[nlen - 3] = ml >> 16 & 0xff;

variant.cpp

@@ -108,8 +108,8 @@ static std::map<Variant::Type, const char*> idToType = {
     {Variant::Type::UI32Matrix,    "UI32Matrix"},
     {Variant::Type::I64Matrix,     "I64Matrix"},
     {Variant::Type::UI64Matrix,    "UI64Matrix"},
-    {Variant::Type::F32Matrix,     "I8Matrix"},
+    {Variant::Type::F32Matrix,     "F32Matrix"},
-    {Variant::Type::F64Matrix,     "UI8Matrix"},
+    {Variant::Type::F64Matrix,     "F64Matrix"},
 };
 
 template<typename T>
@@ -196,9 +196,12 @@ void deserializeVariant(const pugi::xml_node &node, Variant &variant, const Byte
     std::string type = node.attribute("type").as_string();
     Variant::Type typeId = typeToId[type];
 
-    if(typeId == Variant::Type::String && !node.attribute("location"))
+    if(typeId == Variant::Type::String)
     {
-        variant.setValue(node.text().as_string());
+        if(!node.attribute("location"))
+            variant.setValue(node.text().as_string());
+        else
+            variant.setValue(String(data.constData(), data.size()));
     }
     else if(node.attribute("value"))
     {
@@ -400,6 +403,7 @@ Variant variantFromString(Variant::Type type, const String &str)
 
 Variant::Type Variant::type() const
 {
+    int idx = _value.index();
     return (Variant::Type)_value.index();
 }
 
@@ -430,6 +434,32 @@ String Variant::toString() const
         return ss.str();
     };
 
+    auto matrixString = [](auto matrix) {
+        std::stringstream ss;
+        ss << "{";
+        for(int i=0; i<matrix.rows(); i++)
+        {
+            ss << "{";
+            for(int o=0; o<matrix.cols(); o++)
+            {
+#if __GNUC__ >= 11 || __clang__
+                char str[128] = {0};
+                char *end = str + sizeof(str);
+                std::to_chars(str, end, matrix(i, o));
+                ss << str;
+#else
+                ss << std::to_string(matrix(i, o));
+#endif
+                if(o < matrix.cols() - 1)
+                    ss << ",";
+            }
+            ss << "}";
+            if(i < matrix.rows() - 1)
+                ss << ",";
+        }
+        return ss.str();
+    };
+
     switch(type())
     {
     case Variant::Type::Int8: toChars<Int8>(_value, str, end); break;
@@ -454,6 +484,8 @@ String Variant::toString() const
     case Variant::Type::UI64Vector: string = vectorString(std::get<UI64Vector>(_value)); break;
     case Variant::Type::F32Vector: string = vectorString(std::get<F32Vector>(_value)); break;
     case Variant::Type::F64Vector: string = vectorString(std::get<F64Vector>(_value)); break;
+    case Variant::Type::F32Matrix: string = matrixString(std::get<F32Matrix>(_value)); break;
+    case Variant::Type::F64Matrix: string = matrixString(std::get<F64Matrix>(_value)); break;
     case Variant::Type::String: string = std::get<String>(_value); break;
     case Variant::Type::TimePoint:
     {