Add `Buffer::data()`, `empty()`, and `size()` methods with unit tests

Introduce new methods: `data()` to access buffer content, `empty()` to check buffer state, and `size()` to retrieve buffer size. Update unit tests to validate the behavior of these methods alongside existing functionality.

Add `Buffer::data()`, `empty()`, and `size()` methods with unit tests
Introduce new methods: `data()` to access buffer content, `empty()` to check buffer state, and `size()` to retrieve buffer size. Update unit tests to validate the behavior of these methods alongside existing functionality.
m-holger
1 parent 388719d4
Showing 4 changed files with 73 additions and 4 deletions
include/qpdf/Buffer.hh
libqpdf/Buffer.cc
libtests/buffer.cc
manual/release-notes.rst
@@ -76,6 +76,22 @@ class Buffer
     QPDF_DLL
     std::string_view view() const;
  
+    // Return a pointer to the data. NB: Unlike getBuffer, this method returns a valid pointer even
+    // if the Buffer is empty.
+    QPDF_DLL
+    char const* data() const;
+
+    // Return a pointer to the data. NB: Unlike getBuffer, this method returns a valid pointer even
+    // if the Buffer is empty.
+    QPDF_DLL
+    char* data();
+
+    QPDF_DLL
+    bool empty() const;
+
+    QPDF_DLL
+    size_t size() const;
+
   private:
     class Members;
  
@@ -117,3 +117,27 @@ Buffer::view() const
     }
     return {m->buf, m->size};
 }
+
+char const*
+Buffer::data() const
+{
+    return m->buf ? m->buf : m->str.data();
+}
+
+char*
+Buffer::data()
+{
+    return m->buf ? m->buf : m->str.data();
+}
+
+bool
+Buffer::empty() const
+{
+    return m->size == 0;
+}
+
+size_t
+Buffer::size() const
+{
+    return m->size;
+}
@@ -35,13 +35,36 @@ main()
     assert(bc2p[0] == 'R');
     assert(bc2p[1] == 'W');
  
-    // Test move and view method
+    // Test move, view, data, empty and size methods
     assert(bc1.view() == "RW");
+    assert(std::string_view(bc1.data(), bc1.getSize()) == "RW");
+    *bc1.data() = 'Z';
+    assert(!bc1.empty());
+    assert(bc1.size() == 2);
     auto s1 = bc1.move();
-    assert(bc1.getBuffer() == nullptr);
+    assert(bc1.empty());
+    assert(bc1.size() == 0);
+    assert(!bc1.getBuffer());
     assert(bc1.getSize() == 0);
-    assert(s1 == "RW");
+    assert(s1 == "ZW");
     assert(bc1.view().empty());
+    assert(bc1.data());
+    assert(Buffer(s1).move() == "ZW");
+    assert(s1 == "ZW");
+
+    // Test const methods
+    const Buffer cb(s1);
+    assert(*cb.data() == 'Z');
+    assert(*(cb.getBuffer() + 1) == 'W');
+
+    // Test constructors
+    assert(Buffer().empty());
+    assert(Buffer().copy().empty());
+    assert(!Buffer().getBuffer());
+    assert(Buffer().data());
+    assert(Buffer().move().empty());
+    assert(Buffer(s1).size() == 2);
+    assert(*Buffer(s1).data() == 'Z');
  
     // Test Buffer(std:string&&)
     Buffer bc3("QW");
@@ -38,9 +38,15 @@ more detail.
       overhead of repeatedly validating the underlying document structure
       and/or building internal caches. If the underlying document structure
       is directly modified (without the use of DocumentHelpers), the
-      ``validate`` methods revalidates the structure and resynchronizes any
+      ``validate`` methods revalidate the structure and resynchronize any
       internal caches.
  
+    - Add new ``Buffer`` methods ``move``, ``view``, ``data``, ``size`` and
+      ``empty``. The new methods present the ``Buffer`` as a ``char`` (rather
+      than ``unsigned char``) container and facilitate the efficient moving
+      of its content into a `std::string``.
+
+
   - CLI Enhancements
  
    - Disallow option :qpdf:ref:`--deterministic-id` to be used together