Added helper function Photoshop::locatePreviewIrb() which is needed for native previews of Photoshop EPS files

src/jpgimage.cpp

@@ -88,6 +88,7 @@ namespace Exiv2 {
     const char     Photoshop::ps3Id_[] = "Photoshop 3.0\0";
     const char     Photoshop::bimId_[] = "8BIM";
     const uint16_t Photoshop::iptc_    = 0x0404;
+    const uint16_t Photoshop::preview_ = 0x040c;
 
     bool Photoshop::valid(const byte* pPsData,
                           long        sizePsData)
@@ -197,6 +198,16 @@ namespace Exiv2 {
                          record, sizeHdr, sizeData);
     }
 
+    int Photoshop::locatePreviewIrb(const byte*     pPsData,
+                                    long            sizePsData,
+                                    const byte**    record,
+                                    uint32_t *const sizeHdr,
+                                    uint32_t *const sizeData)
+    {
+        return locateIrb(pPsData, sizePsData, preview_,
+                         record, sizeHdr, sizeData);
+    }
+
     DataBuf Photoshop::setIptcIrb(const byte*     pPsData,
                                   long            sizePsData,
                                   const IptcData& iptcData)

src/jpgimage.hpp

@@ -66,6 +66,7 @@ namespace Exiv2 {
         static const char     ps3Id_[]; //!< %Photoshop marker
         static const char     bimId_[]; //!< %Photoshop marker
         static const uint16_t iptc_;    //!< %Photoshop IPTC marker
+        static const uint16_t preview_; //!< %Photoshop preview marker
 
         /*!
           @brief Validates all IRBs
@@ -108,6 +109,14 @@ namespace Exiv2 {
                                  const byte **record,
                                  uint32_t *const sizeHdr,
                                  uint32_t *const sizeData);
+        /*!
+          @brief Forwards to locatePreviewIrb() with \em psTag = \em preview_
+         */
+        static int locatePreviewIrb(const byte *pPsData,
+                                    long sizePsData,
+                                    const byte **record,
+                                    uint32_t *const sizeHdr,
+                                    uint32_t *const sizeData);
         /*!
           @brief Set the new IPTC IRB, keeps existing IRBs but removes the
                  IPTC block if there is no new IPTC data to write.