New data_buffer() method to get the image buffer.

4 files changed, 58 insertions, 0 deletions

diff --git a/src/exiv2wrapper.cpp b/src/exiv2wrapper.cpp
index a0b6e59..8ee13de 100644
--- a/src/exiv2wrapper.cpp
+++ b/src/exiv2wrapper.cpp
@@ -484,6 +484,51 @@ void Image::copyMetadata(Image& other, bool exif, bool iptc, bool xmp) const
         other._xmpData = _xmpData;
 }
 
+std::string Image::getDataBuffer() const
+{
+    Exiv2::BasicIo& io = _image->io();
+    long size = io.size();
+    long pos = -1;
+
+    if (io.isopen())
+    {
+        // Remember the current position in the stream
+        pos = io.tell();
+        // Go to the beginning of the stream
+        io.seek(0, Exiv2::BasicIo::beg);
+    }
+    else
+    {
+        io.open();
+    }
+
+    // Copy the data buffer in a string. Since the data buffer can contain null
+    // characters ('\x00'), the string cannot be simply constructed like that:
+    //     _data = std::string((char*) previewImage.pData());
+    // because it would be truncated after the first occurence of a null
+    // character. Therefore, it has to be copied character by character.
+    // First allocate the memory for the whole string...
+    std::string buffer(size, ' ');
+    // ... then fill it with the raw data.
+    for (unsigned long i = 0; i < size; ++i)
+    {
+        io.read((Exiv2::byte*) &buffer[i], 1);
+    }
+
+    if (pos == -1)
+    {
+        // The stream was initially closed
+        io.close();
+    }
+    else
+    {
+        // Reset to the initial position in the stream
+        io.seek(pos, Exiv2::BasicIo::beg);
+    }
+
+    return buffer;
+}
+
 
 ExifTag::ExifTag(const std::string& key, Exiv2::Exifdatum* datum, Exiv2::ExifData* data): _key(key)
 {
diff --git a/src/exiv2wrapper.hpp b/src/exiv2wrapper.hpp
index c0fb46c..5443f2b 100644
--- a/src/exiv2wrapper.hpp
+++ b/src/exiv2wrapper.hpp
@@ -225,6 +225,9 @@ public:
     // Copy the metadata to another image.
     void copyMetadata(Image& other, bool exif=true, bool iptc=true, bool xmp=true) const;
 
+    // Return the image data buffer.
+    std::string getDataBuffer() const;
+
 private:
     std::string _filename;
     Exiv2::Image::AutoPtr _image;
diff --git a/src/exiv2wrapper_python.cpp b/src/exiv2wrapper_python.cpp
index aab2925..5a03132 100644
--- a/src/exiv2wrapper_python.cpp
+++ b/src/exiv2wrapper_python.cpp
@@ -148,6 +148,8 @@ BOOST_PYTHON_MODULE(libexiv2python)
         .def("_previews", &Image::previews)
 
         .def("_copyMetadata", &Image::copyMetadata)
+
+        .def("_getDataBuffer", &Image::getDataBuffer)
     ;
 }
 
diff --git a/src/pyexiv2/metadata.py b/src/pyexiv2/metadata.py
index f49f92b..61132ab 100644
--- a/src/pyexiv2/metadata.py
+++ b/src/pyexiv2/metadata.py
@@ -387,3 +387,11 @@ class ImageMetadata(object):
             other._keys['xmp'] = None
             other._tags['xmp'] = {}
 
+    def data_buffer(self):
+        """
+        Return the image data as a string.
+        If metadata has been modified, the data buffer won't be up-to-date until
+        write() is called.
+        """ 
+        return self._image._getDataBuffer()
+