Streamreader

src/bufferstreamer.h

@@ -0,0 +1,78 @@
+/*
+ * Copyright (C) 2020 Veloman Yunkan
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * is provided AS IS, WITHOUT ANY WARRANTY; without even the implied
+ * warranty of MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, and
+ * NON-INFRINGEMENT.  See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+ *
+ */
+
+#ifndef ZIM_BUFFERSTREAMER_H
+#define ZIM_BUFFERSTREAMER_H
+
+#include "debug.h"
+
+#include <string.h>
+
+namespace zim
+{
+
+class BufferStreamer
+{
+public: // functions
+  explicit BufferStreamer(const Buffer& buffer, zsize_t size)
+    : m_buffer(buffer),
+      m_current(buffer.data()),
+      m_size(size)
+  {}
+
+  explicit BufferStreamer(const Buffer& buffer)
+    : BufferStreamer(buffer, buffer.size())
+  {}
+
+  // Reads a value of the said type from the stream
+  //
+  // For best portability this function should be used with types of known
+  // bit-width (int32_t, uint16_t, etc) rather than builtin types with
+  // unknown bit-width (int, unsigned, etc).
+  template<typename T> T read()
+  {
+    const size_t N(sizeof(T));
+    char buf[N];
+    memcpy(buf, m_current, N);
+    skip(zsize_t(N));
+    return fromLittleEndian<T>(buf); // XXX: This handles only integral types
+  }
+
+  const char* current() const {
+    return m_current;
+  }
+
+  zsize_t left() const {
+    return m_size;
+  }
+
+  void skip(zsize_t nbBytes) {
+    m_current += nbBytes.v;
+    m_size -= nbBytes;
+  }
+
+private: // data
+  const Buffer m_buffer;
+  const char* m_current;
+  zsize_t m_size;
+};
+
+} // namespace zim
+
+#endif // ZIM_BUFDATASTREAM_H

src/istreamreader.cpp

@@ -19,7 +19,6 @@
 
 #include "istreamreader.h"
 #include "file_reader.h"
-#include "bufdatastream.h"
 
 namespace zim
 {
@@ -36,38 +35,4 @@ IStreamReader::sub_reader(zsize_t size)
   return std::unique_ptr<Reader>(new BufferReader(buffer));
 }
 
-////////////////////////////////////////////////////////////////////////////////
-// 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

test/bufferstreamer.cpp

@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) 2020 Veloman Yunkan
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * is provided AS IS, WITHOUT ANY WARRANTY; without even the implied
+ * warranty of MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, and
+ * NON-INFRINGEMENT.  See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+ *
+ */
+
+#include "buffer.h"
+#include "bufferstreamer.h"
+#include "endian_tools.h"
+
+#include "gtest/gtest.h"
+
+namespace
+{
+
+using namespace zim;
+
+////////////////////////////////////////////////////////////////////////////////
+// BufferStreamer
+////////////////////////////////////////////////////////////////////////////////
+
+std::string toString(const Buffer& buffer)
+{
+  return std::string(buffer.data(), buffer.size().v);
+}
+
+TEST(BufferStreamer, shouldJustWork)
+{
+  char data[] = "abcdefghijklmnopqrstuvwxyz";
+  zim::toLittleEndian(uint32_t(1234), data);
+  zim::toLittleEndian(int64_t(-987654321), data+18);
+
+  auto buffer = Buffer::makeBuffer(data, zsize_t(sizeof(data)));
+  zim::BufferStreamer bds(buffer, zsize_t(sizeof(data)));
+
+  ASSERT_EQ(1234, bds.read<uint32_t>());
+
+  ASSERT_EQ(data + 4, bds.current());
+  const auto blob1 = std::string(bds.current(), 4);
+  bds.skip(zsize_t(4));
+  ASSERT_EQ("efgh", blob1);
+
+  ASSERT_EQ(data + 8, bds.current());
+  const auto blob2 = std::string(bds.current(), 10);
+  bds.skip(zsize_t(10));
+  ASSERT_EQ("ijklmnopqr", blob2);
+
+  ASSERT_EQ(-987654321,   bds.read<int64_t>());
+}
+
+} // unnamed namespace

test/istreamreader.cpp

@@ -18,15 +18,14 @@
  */
 
 #include "istreamreader.h"
-#include "bufdatastream.h"
 #include "endian_tools.h"
 
 #include "gtest/gtest.h"
 
 namespace
 {
 
-using zim::IStreamReader;
+using namespace zim;
 
 ////////////////////////////////////////////////////////////////////////////////
 // IDataStream
@@ -64,35 +63,4 @@ TEST(IStreamReader, sub_reader)
   EXPECT_EQ(0, memcmp(buffer.data(), zerobuf, N));
 }
 
-////////////////////////////////////////////////////////////////////////////////
-// BufDataStream
-////////////////////////////////////////////////////////////////////////////////
-
-std::string toString(const IDataStream::Blob& blob)
-{
-  return std::string(blob.data(), blob.size());
-}
-
-TEST(BufDataStream, shouldJustWork)
-{
-  char data[] = "abcdefghijklmnopqrstuvwxyz";
-  zim::toLittleEndian(uint32_t(1234), data);
-  zim::toLittleEndian(int64_t(-987654321), data+18);
-
-  zim::BufDataStream bds(data, sizeof(data));
-  IDataStream& ids = bds;
-
-  ASSERT_EQ(1234,         ids.read<uint32_t>());
-
-  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>());
-}
-
 } // unnamed namespace

test/meson.build

@@ -14,7 +14,8 @@ tests = [
     'impl_find',
     'istreamreader',
     'decoderstreamreader',
-    'rawstreamreader'
+    'rawstreamreader',
+    'bufferstreamer'
 ]
 
 if gtest_dep.found() and not meson.is_cross_build()