Bump minor version and add new api to get if archive has alias.

Fix #844

include/zim/archive.h

@@ -462,6 +462,20 @@ namespace zim
        */
       bool hasNewNamespaceScheme() const;
 
+      /** Get if the zim archive may have alias entries.
+       *
+       * Alias entries are entries (two at least) pointing to the same
+       * content (same cluster/blob id).
+       *
+       * This method is just a hint.
+       * If true, its means that zim archive has been created with a implementation
+       * allowing alias creation.
+       * If false, it means that zim archive has been created before we
+       * formalize alias concept. But it would be still valid (from the spec)
+       * to have alias in the archive.
+       */
+      bool mayHaveAliasEntry() const;
+
       /** Get a shared ptr on the FileImpl
        *
        *  @internal

src/archive.cpp

@@ -487,6 +487,11 @@ namespace zim
     return m_impl->hasNewNamespaceScheme();
   }
 
+  bool Archive::mayHaveAliasEntry() const
+  {
+    return m_impl->mayHaveAliasEntry();
+  }
+
   cluster_index_type Archive::getClusterCount() const
   {
     return cluster_index_type(m_impl->getCountClusters());

src/fileheader.cpp

@@ -41,7 +41,7 @@ namespace zim
   const uint32_t Fileheader::zimMagic = 0x044d495a; // ="ZIM^d"
   const uint16_t Fileheader::zimOldMajorVersion = 5;
   const uint16_t Fileheader::zimMajorVersion = 6;
-  const uint16_t Fileheader::zimMinorVersion = 1;
+  const uint16_t Fileheader::zimMinorVersion = 2;
   const offset_type Fileheader::size = 80; // This is also mimeListPos (so an offset)
 
   void Fileheader::write(int out_fd) const

src/fileimpl.cpp

@@ -599,6 +599,10 @@ class Grouping
     return zimReader->size();
   }
 
+  bool FileImpl::mayHaveAliasEntry() const {
+    return header.getMinorVersion() >= 2;
+  }
+
   bool FileImpl::is_multiPart() const {
     return zimFile->is_multiPart();
   }

src/fileimpl.h

@@ -115,6 +115,7 @@ namespace zim
       zsize_t getFilesize() const;
       bool hasNewNamespaceScheme() const { return m_newNamespaceScheme; }
       bool hasFrontArticlesIndex() const { return m_hasFrontArticlesIndex; }
+      bool mayHaveAliasEntry() const;
 
       FileCompound::PartRange getFileParts(offset_t offset, zsize_t size);
       std::shared_ptr<const Dirent> getDirent(entry_index_t idx);