BufDataStream::readBlobImpl

openzim · Aug 30, 2020 · b850bfd · b850bfd
1 parent ae53b8a
commit b850bfd
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Showing 3 changed files with 52 additions and 9 deletions.
diff --git a/src/bufdatastream.h b/src/bufdatastream.h
@@ -36,13 +36,10 @@ class BufDataStream : public IDataStream
     , size_(size)
   {}
 
-  void readImpl(void* buf, size_t nbytes) override
-  {
-    ASSERT(nbytes, <=, size_);
-    memcpy(buf, data_, nbytes);
-    data_ += nbytes;
-    size_ -= nbytes;
-  }
+protected:
+  void readImpl(void* buf, size_t nbytes) override;
+  Blob readBlobImpl(size_t size) override;
+
 
 private: // data
   const char* data_;

diff --git a/src/idatastream.cpp b/src/idatastream.cpp
@@ -18,10 +18,15 @@
  */
 
 #include "idatastream.h"
+#include "bufdatastream.h"
 
 namespace zim
 {
 
+////////////////////////////////////////////////////////////////////////////////
+// IDataStream
+////////////////////////////////////////////////////////////////////////////////
+
 IDataStream::Blob
 IDataStream::readBlobImpl(size_t size)
 {
@@ -30,4 +35,38 @@ IDataStream::readBlobImpl(size_t size)
   return Blob(buf, size);
 }
 
+////////////////////////////////////////////////////////////////////////////////
+// BufDataStream
+////////////////////////////////////////////////////////////////////////////////
+
+void
+BufDataStream::readImpl(void* buf, size_t nbytes)
+{
+  ASSERT(nbytes, <=, size_);
+  memcpy(buf, data_, nbytes);
+  data_ += nbytes;
+  size_ -= nbytes;
+}
+
+namespace
+{
+
+struct NoDelete
+{
+  template<class T> void operator()(T*) {}
+};
+
+} // unnamed namespace
+
+IDataStream::Blob
+BufDataStream::readBlobImpl(size_t nbytes)
+{
+  ASSERT(nbytes, <=, size_);
+  const IDataStream::Blob::DataPtr dataPtr(data_, NoDelete());
+  const IDataStream::Blob blob(dataPtr, nbytes);
+  data_ += nbytes;
+  size_ -= nbytes;
+  return blob;
+}
+
 } // namespace zim
diff --git a/test/idatastream.cpp b/test/idatastream.cpp
@@ -80,8 +80,15 @@ TEST(BufDataStream, shouldJustWork)
   IDataStream& ids = bds;
 
   ASSERT_EQ(1234,         ids.read<uint32_t>());
-  ASSERT_EQ("efgh",       toString(ids.readBlob(4)));
-  ASSERT_EQ("ijklmnopqr", toString(ids.readBlob(10)));
+
+  const auto blob1 = ids.readBlob(4);
+  ASSERT_EQ("efgh", toString(blob1));
+  ASSERT_EQ(data + 4, blob1.data());
+
+  const auto blob2 = ids.readBlob(10);
+  ASSERT_EQ("ijklmnopqr", toString(blob2));
+  ASSERT_EQ(data + 8, blob2.data());
+
   ASSERT_EQ(-987654321,   ids.read<int64_t>());
 }